fix(ai): preserve Gemini agent loop parity (#41109)

Co-authored-by: Aiden Cline <rekram1-node@users.noreply.github.com>

bun.lock

@@ -395,6 +395,7 @@
         "ignore": "7.0.5",
         "immer": "11.1.4",
         "jsonc-parser": "3.3.1",
+        "mime-types": "3.0.2",
         "tree-sitter-bash": "0.25.0",
         "tree-sitter-powershell": "0.25.10",
         "turndown": "7.2.0",

packages/ai/src/protocols/gemini.ts

@@ -25,8 +25,20 @@ import { ToolSchemaProjection } from "./utils/tool-schema"
 
 const ADAPTER = "gemini"
 const MEDIA_MIMES = new Set<string>(ProviderShared.MEDIA_MIMES)
+// Google documents this sentinel for replaying Gemini 3 function calls after their original signature was lost.
+const SKIP_THOUGHT_SIGNATURE_VALIDATOR = "skip_thought_signature_validator"
 export const DEFAULT_BASE_URL = "https://generativelanguage.googleapis.com/v1beta"
 
+// Gemini 3 rejects replayed function calls without a thought signature. Google's SDKs avoid that in normal chats by
+// retaining complete model responses, but OpenCode reconstructs durable history and may encounter an unsigned call
+// from an older or external session. Model IDs are open-ended, so unknown Gemini aliases inherit current behavior.
+const requiresThoughtSignatureFallback = (modelID: string) => {
+  if (!/(^|\/)gemini-/i.test(modelID)) return false
+  if (/(^|\/)gemini-(?:1|2)(?:[.-]|$)/i.test(modelID)) return false
+  if (/(^|\/)gemini-pro(?:-vision)?$/i.test(modelID)) return false
+  return !/(^|\/)gemini-robotics-er-1\.5(?:[.-]|$)/i.test(modelID)
+}
+
 export interface OptionsInput {
   readonly [key: string]: unknown
   readonly cachedContent?: string
@@ -145,6 +157,9 @@ const GeminiGenerationConfig = Schema.Struct({
   temperature: Schema.optional(Schema.Number),
   topP: Schema.optional(Schema.Number),
   topK: Schema.optional(Schema.Number),
+  frequencyPenalty: Schema.optional(Schema.Number),
+  presencePenalty: Schema.optional(Schema.Number),
+  seed: Schema.optional(Schema.Number),
   stopSequences: optionalArray(Schema.String),
   thinkingConfig: Schema.optional(GeminiThinkingConfig),
 })
@@ -202,11 +217,13 @@ interface ParserState {
 //    keys on non-object scalars. Mirrors OpenCode's historical Gemini rules.
 //
 // 2. Project — lossy mapping from JSON Schema to Gemini's schema dialect:
-//    drop empty objects, derive `nullable: true` from `type: [..., "null"]`,
-//    coerce `const` to `[const]` enum, recurse properties/items, propagate
+//    drop empty root parameter schemas while preserving nested empty objects,
+//    expand type arrays into `anyOf`, derive `nullable: true` from null members,
+//    coerce `const` to `[const]` enum, recurse properties/items, and propagate
 //    only an allowlisted set of keys (description, required, format, type,
-//    properties, items, allOf, anyOf, oneOf, minLength). Anything outside the
-//    allowlist (e.g. `additionalProperties`, `$ref`) is silently dropped.
+//    nullable, enum, properties, items, allOf, anyOf, oneOf, minLength).
+//    Anything outside the allowlist (e.g. `additionalProperties`, `$ref`) is
+//    silently dropped.
 //
 // Sanitize runs first, then project. The implementation lives in
 // `utils/gemini-tool-schema` so this protocol keeps the same shape as the other
@@ -282,6 +299,8 @@ const lowerMessages = Effect.fn("Gemini.lowerMessages")(function* (request: LLMR
 
     if (message.role === "assistant") {
       const parts: Array<Schema.Schema.Type<typeof GeminiContentPart>> = []
+      // Parallel Gemini 3 calls may carry one signature on the first call; unsigned sibling calls are valid.
+      let hasSignedToolCall = false
       for (const part of message.content) {
         if (!ProviderShared.supportsContent(part, ["text", "reasoning", "tool-call"]))
           return yield* ProviderShared.unsupportedContent("Gemini", "assistant", ["text", "reasoning", "tool-call"])
@@ -294,7 +313,17 @@ const lowerMessages = Effect.fn("Gemini.lowerMessages")(function* (request: LLMR
           continue
         }
         if (part.type === "tool-call") {
-          parts.push(lowerToolCall(part))
+          const lowered = lowerToolCall(part)
+          const signature = lowered.thoughtSignature
+          parts.push({
+            ...lowered,
+            thoughtSignature:
+              signature ??
+              (requiresThoughtSignatureFallback(request.model.id) && !hasSignedToolCall
+                ? SKIP_THOUGHT_SIGNATURE_VALIDATOR
+                : undefined),
+          })
+          if (signature !== undefined) hasSignedToolCall = true
           continue
         }
       }
@@ -388,6 +417,9 @@ const fromRequest = Effect.fn("Gemini.fromRequest")(function* (request: LLMReque
     temperature: generation?.temperature,
     topP: generation?.topP,
     topK: generation?.topK,
+    frequencyPenalty: generation?.frequencyPenalty,
+    presencePenalty: generation?.presencePenalty,
+    seed: generation?.seed,
     stopSequences: generation?.stop,
     thinkingConfig: options.thinkingConfig,
   }

packages/ai/src/protocols/utils/gemini-tool-schema.ts

@@ -61,37 +61,57 @@ const emptyObjectSchema = (schema: Record<string, unknown>) =>
   (!isRecord(schema.properties) || Object.keys(schema.properties).length === 0) &&
   !schema.additionalProperties
 
-const projectNode = (schema: unknown): Record<string, unknown> | undefined => {
+const projectNode = (schema: unknown, nested = false): Record<string, unknown> | undefined => {
   if (!isRecord(schema)) return undefined
-  if (emptyObjectSchema(schema)) return undefined
-  return Object.fromEntries(
+  if (!nested && emptyObjectSchema(schema)) return undefined
+  const types = Array.isArray(schema.type) ? schema.type.filter((type) => type !== "null") : undefined
+  const anyOf = Array.isArray(schema.anyOf) ? schema.anyOf : undefined
+  const hasNullAnyOf = anyOf?.some((item) => isRecord(item) && item.type === "null") ?? false
+  const anyOfTypes = hasNullAnyOf ? anyOf?.filter((item) => !isRecord(item) || item.type !== "null") : anyOf
+  const flattenedAnyOf = hasNullAnyOf && anyOfTypes?.length === 1 ? projectNode(anyOfTypes[0], true) : undefined
+  const result = Object.fromEntries(
     [
       ["description", schema.description],
       ["required", schema.required],
       ["format", schema.format],
-      ["type", Array.isArray(schema.type) ? schema.type.filter((type) => type !== "null")[0] : schema.type],
-      ["nullable", Array.isArray(schema.type) && schema.type.includes("null") ? true : undefined],
+      ["type", types ? (types.length === 0 ? "null" : undefined) : schema.type],
+      [
+        "nullable",
+        (Array.isArray(schema.type) && schema.type.includes("null") && types && types.length > 0) || hasNullAnyOf
+          ? true
+          : undefined,
+      ],
       ["enum", schema.const !== undefined ? [schema.const] : schema.enum],
       [
         "properties",
         isRecord(schema.properties)
-          ? Object.fromEntries(Object.entries(schema.properties).map(([key, value]) => [key, projectNode(value)]))
+          ? Object.fromEntries(Object.entries(schema.properties).map(([key, value]) => [key, projectNode(value, true)]))
           : undefined,
       ],
       [
         "items",
         Array.isArray(schema.items)
-          ? schema.items.map(projectNode)
+          ? schema.items.map((item) => projectNode(item, true))
           : schema.items === undefined
             ? undefined
-            : projectNode(schema.items),
+            : projectNode(schema.items, true),
       ],
-      ["allOf", Array.isArray(schema.allOf) ? schema.allOf.map(projectNode) : undefined],
-      ["anyOf", Array.isArray(schema.anyOf) ? schema.anyOf.map(projectNode) : undefined],
-      ["oneOf", Array.isArray(schema.oneOf) ? schema.oneOf.map(projectNode) : undefined],
+      ["allOf", Array.isArray(schema.allOf) ? schema.allOf.map((item) => projectNode(item, true)) : undefined],
+      [
+        "anyOf",
+        anyOfTypes
+          ? hasNullAnyOf && anyOfTypes.length === 1
+            ? undefined
+            : anyOfTypes.map((item) => projectNode(item, true))
+          : types && types.length > 0
+            ? types.map((type) => ({ type }))
+            : undefined,
+      ],
+      ["oneOf", Array.isArray(schema.oneOf) ? schema.oneOf.map((item) => projectNode(item, true)) : undefined],
       ["minLength", schema.minLength],
     ].filter((entry) => entry[1] !== undefined),
   )
+  return flattenedAnyOf ? { ...result, ...flattenedAnyOf } : result
 }
 
 export const convert = (schema: unknown) => projectNode(sanitizeNode(schema))

packages/ai/test/provider/gemini.test.ts

@@ -16,6 +16,13 @@ const model = Gemini.route
   })
   .model({ id: "gemini-2.5-flash" })
 
+const gemini3 = Gemini.route
+  .with({
+    endpoint: { baseURL: "https://generativelanguage.test/v1beta/" },
+    auth: Auth.header("x-goog-api-key", "test"),
+  })
+  .model({ id: "gemini-3-flash-preview" })
+
 const request = LLM.request({
   id: "req_1",
   model,
@@ -86,6 +93,39 @@ describe("Gemini route", () => {
     }),
   )
 
+  it.effect("forwards standard Gemini generation options", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model,
+          prompt: "Say hello.",
+          generation: {
+            maxTokens: 40,
+            temperature: 0.2,
+            topP: 0.8,
+            topK: 12,
+            frequencyPenalty: 0.3,
+            presencePenalty: 0.4,
+            seed: 42,
+            stop: ["done"],
+          },
+        }),
+      )
+
+      expect(prepared.body.generationConfig).toEqual({
+        maxOutputTokens: 40,
+        temperature: 0.2,
+        topP: 0.8,
+        topK: 12,
+        frequencyPenalty: 0.3,
+        presencePenalty: 0.4,
+        seed: 42,
+        stopSequences: ["done"],
+        thinkingConfig: undefined,
+      })
+    }),
+  )
+
   it.effect("lowers chronological system updates to wrapped user text in order", () =>
     Effect.gen(function* () {
       const prepared = yield* compileRequest(
@@ -350,6 +390,100 @@ describe("Gemini route", () => {
     }),
   )
 
+  it.effect("preserves nested empty object tool schemas", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model,
+          prompt: "Use the tool.",
+          tools: [
+            {
+              name: "configure",
+              description: "Configure the operation",
+              inputSchema: {
+                type: "object",
+                required: ["options"],
+                properties: {
+                  options: { type: "object", description: "Optional provider settings", properties: {} },
+                },
+              },
+            },
+          ],
+        }),
+      )
+
+      expect(prepared.body.tools).toEqual([
+        {
+          functionDeclarations: [
+            {
+              name: "configure",
+              description: "Configure the operation",
+              parameters: {
+                type: "object",
+                required: ["options"],
+                properties: {
+                  options: { type: "object", description: "Optional provider settings", properties: {} },
+                },
+              },
+            },
+          ],
+        },
+      ])
+    }),
+  )
+
+  it.effect("projects Gemini type arrays without narrowing their allowed values", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model,
+          prompt: "Use the tool.",
+          tools: [
+            {
+              name: "filter",
+              description: "Filter values",
+              inputSchema: {
+                type: "object",
+                properties: {
+                  status: { type: ["number", "string"], description: "Status filter" },
+                  maybe: { type: ["string", "null"] },
+                  nothing: { type: ["null"] },
+                  explicit: { anyOf: [{ type: "string" }, { type: "null" }] },
+                  choice: { anyOf: [{ type: "string" }, { type: "number" }, { type: "null" }] },
+                },
+              },
+            },
+          ],
+        }),
+      )
+
+      expect(prepared.body.tools?.[0]?.functionDeclarations[0]?.parameters).toEqual({
+        type: "object",
+        properties: {
+          status: {
+            description: "Status filter",
+            anyOf: [{ type: "number" }, { type: "string" }],
+          },
+          maybe: {
+            nullable: true,
+            anyOf: [{ type: "string" }],
+          },
+          nothing: {
+            type: "null",
+          },
+          explicit: {
+            type: "string",
+            nullable: true,
+          },
+          choice: {
+            anyOf: [{ type: "string" }, { type: "number" }],
+            nullable: true,
+          },
+        },
+      })
+    }),
+  )
+
   it.effect("parses text, reasoning, and usage stream fixtures", () =>
     Effect.gen(function* () {
       const body = sseEvents(
@@ -536,6 +670,44 @@ describe("Gemini route", () => {
     }),
   )
 
+  it.effect("replays unsigned Gemini 3 tool calls with the validator bypass sentinel", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model: gemini3,
+          messages: [
+            Message.assistant([ToolCallPart.make({ id: "tool_0", name: "lookup", input: { query: "weather" } })]),
+            Message.tool({ id: "tool_0", name: "lookup", result: "done", resultType: "text" }),
+          ],
+        }),
+      )
+
+      expect(prepared.body.contents).toEqual([
+        {
+          role: "model",
+          parts: [
+            {
+              functionCall: { id: undefined, name: "lookup", args: { query: "weather" } },
+              thoughtSignature: "skip_thought_signature_validator",
+            },
+          ],
+        },
+        {
+          role: "user",
+          parts: [
+            {
+              functionResponse: {
+                id: undefined,
+                name: "lookup",
+                response: { name: "lookup", content: "done" },
+              },
+            },
+          ],
+        },
+      ])
+    }),
+  )
+
   it.effect("emits streamed tool calls and maps finish reason", () =>
     Effect.gen(function* () {
       const body = sseEvents({

packages/app/src/pages/session.tsx

@@ -688,6 +688,8 @@ export default function Page() {
     return {
       queryKey: [...vcsKey(), mode] as const,
       enabled,
+      refetchOnMount: "always" as const,
+      refetchOnWindowFocus: true,
       queryFn: mode
         ? () =>
             sdk()
@@ -701,6 +703,16 @@ export default function Page() {
     }
   })
   const refreshVcs = debounce(() => void queryClient.invalidateQueries({ queryKey: vcsKey() }), 100)
+  createEffect(
+    on(
+      () => desktopReviewOpen() || mobileChanges(),
+      (open, previous) => {
+        if (!open || previous || !desktopFileTreeOpen() || vcsQuery.isFetching) return
+        refreshVcs()
+      },
+      { defer: true },
+    ),
+  )
   const reviewDiffs = () => {
     if (reviewMode() === "git" || reviewMode() === "branch")
       // avoids suspense
@@ -947,19 +959,6 @@ export default function Page() {
     ),
   )
 
-  const stopVcs = sdk().event.listen((evt) => {
-    const details = evt.details as { type: string; properties?: unknown }
-    if (details.type !== "file.watcher.updated" && details.type !== "filesystem.changed") return
-    const props =
-      typeof details.properties === "object" && details.properties
-        ? (details.properties as Record<string, unknown>)
-        : undefined
-    const file = typeof props?.file === "string" ? props.file : undefined
-    if (!file || file.startsWith(".git/")) return
-    refreshVcs()
-  })
-  onCleanup(stopVcs)
-
   createEffect(
     on(
       () => sdk().directory,

packages/core/package.json

@@ -118,6 +118,7 @@
     "immer": "11.1.4",
     "ignore": "7.0.5",
     "jsonc-parser": "3.3.1",
+    "mime-types": "3.0.2",
     "turndown": "7.2.0",
     "tree-sitter-bash": "0.25.0",
     "tree-sitter-powershell": "0.25.10",

packages/core/src/config/plugin/provider.ts

@@ -13,12 +13,14 @@ export const Plugin = define({
     const config = yield* Config.Service
     const loaded = { entries: yield* config.entries() }
     yield* ctx.integration.transform((integrations) => {
-      const configuredIntegrations = new Set(
-        configuredProviders(loaded.entries).flatMap(([id, provider]) => (provider.env === undefined ? [] : [id])),
-      )
       for (const [id, provider] of configuredProviders(loaded.entries)) {
         const integrationID = id
-        if (!configuredIntegrations.has(id) && !integrations.get(integrationID)) continue
+        if (!integrations.get(integrationID)) {
+          integrations.method.update({
+            integrationID,
+            method: { type: "key", label: "Manually enter API Key" },
+          })
+        }
         integrations.update(integrationID, (integration) => {
           integration.name = provider.name ?? integration.name
         })

packages/core/src/environment/environment.ts

@@ -0,0 +1,26 @@
+import { CrossSpawnSpawner } from "@opencode-ai/util/cross-spawn-spawner"
+import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
+import { Context, Effect, Layer } from "effect"
+import { ChildProcessSpawner } from "effect/unstable/process/ChildProcessSpawner"
+import type { Files } from "./files"
+import { makeFiles } from "./index"
+import { makeLocalDriver } from "./local"
+
+export interface Interface {
+  readonly files: Files
+  readonly spawner: ChildProcessSpawner["Service"]
+}
+
+export class Service extends Context.Service<Service, Interface>()("@opencode/Environment") {}
+
+const layer = Layer.effect(
+  Service,
+  Effect.gen(function* () {
+    const spawner = yield* ChildProcessSpawner
+    return Service.of({ files: makeFiles(makeLocalDriver(spawner)), spawner })
+  }),
+)
+
+export const node = makeLocationNode({ service: Service, layer, deps: [CrossSpawnSpawner.node] })
+
+export * as EnvironmentService from "./environment"

packages/core/src/environment/exec-defaults.ts

@@ -50,13 +50,13 @@ fi
 `
 
 const listScript = `
-${loadMetadata()}
+${loadMetadata("-L")}
 kind=\${metadata%%${TAB}*}
 if [ "$kind" != directory ]; then
   printf '%s' "$kind" >&2
   exit ${WRONG_KIND}
 fi
-find "$1" -mindepth 1 -maxdepth 1 -printf '%y\\0%f\\0'
+find -H "$1" -mindepth 1 -maxdepth 1 -printf '%y\\0%f\\0'
 `
 
 const moveScript = `

packages/core/src/environment/files.ts

@@ -30,7 +30,8 @@ export class Failed extends Schema.TaggedErrorClass<Failed>()("Environment.Faile
 
 export interface FilesImpl {
   /**
-   * Reads a file, following a final symlink so `info` describes the target whose bytes are returned.
+   * Content operations (`read`, `list`) follow final symlinks; metadata operations (`stat` and entry
+   * tags returned by `list`) do not. `info` describes the target file whose bytes are returned.
    * The process-backed default caps collected output at 64 MiB; larger whole-file reads fail with
    * `Failed`, so callers must use ranges for larger files.
    */
@@ -41,7 +42,7 @@ export interface FilesImpl {
   readonly write: (path: string, bytes: Uint8Array) => Effect.Effect<void, Failed>
   /** Describes the path entry itself, so a final symlink is reported as `symlink` rather than followed. */
   readonly stat: (path: string) => Effect.Effect<FileInfo, NotFound | Failed>
-  /** Lists a directory entry without following a final symlink; intermediate symlinks are traversed. */
+  /** Follows a final symlink to the listed directory while preserving each returned entry's own type. */
   readonly list: (path: string) => Effect.Effect<ReadonlyArray<DirEntry>, NotFound | WrongKind | Failed>
   readonly remove: (path: string) => Effect.Effect<void, Failed>
   readonly move: (from: string, to: string) => Effect.Effect<void, NotFound | Failed>
@@ -50,4 +51,20 @@ export interface FilesImpl {
 
 export interface Files extends FilesImpl {}
 
+/**
+ * Derives a follow-stat kind from the lstat-like Files contract. A dangling
+ * symlink fails with `NotFound`.
+ */
+export const typeFollowing = (files: Files, path: string) =>
+  files.stat(path).pipe(
+    Effect.flatMap((info) =>
+      info.type === "symlink"
+        ? files.read(path, { offset: 0, length: 0 }).pipe(
+            Effect.map((result) => result.info.type),
+            Effect.catchTag("Environment.WrongKind", (error) => Effect.succeed(error.actual)),
+          )
+        : Effect.succeed(info.type),
+    ),
+  )
+
 export * as EnvironmentFiles from "./files"

packages/core/src/environment/index.ts

@@ -9,10 +9,13 @@ export {
   type FilesImpl,
   type FileType,
   NotFound,
+  typeFollowing,
   WrongKind,
 } from "./files"
 export { execDefaults } from "./exec-defaults"
+export { makeLocalDriver } from "./local"
 export { makeMemoryDriver, type MemoryDriver } from "./memory"
+export { type Interface, node, Service } from "./environment"
 
 import type { Driver } from "./driver"
 import { execDefaults } from "./exec-defaults"

packages/core/src/environment/local.ts

@@ -0,0 +1,103 @@
+import fs from "node:fs/promises"
+import path from "node:path"
+import { Effect } from "effect"
+import type { ChildProcessSpawner } from "effect/unstable/process/ChildProcessSpawner"
+import type { Driver } from "./driver"
+import { Failed, NotFound, WrongKind, type FileInfo, type FilesImpl, type FileType } from "./files"
+
+/**
+ * The host filesystem binding. Deliberately raw node:fs rather than effect's
+ * FileSystem service or FSUtil: the contract needs lstat semantics (stat
+ * reports "symlink") and typed directory entries, and effect's node
+ * FileSystem provides neither — its stat always follows symlinks and
+ * readDirectory returns names only. FSUtil hits the same gap and its
+ * readDirectoryEntries already bypasses to raw node readdir internally.
+ * Nothing above the environment seam touches node:fs.
+ */
+export const makeLocalDriver = (spawner: ChildProcessSpawner["Service"]): Driver => {
+  const overrides: FilesImpl = {
+    read: (value, range) =>
+      Effect.gen(function* () {
+        const info = yield* stat(value, true)
+        if (info.type !== "file") return yield* new WrongKind({ path: value, actual: info.type })
+        if (range === undefined) {
+          const bytes = yield* attempt(value, () => fs.readFile(value), true)
+          return { info, bytes }
+        }
+        const bytes = yield* attempt(
+          value,
+          async () => {
+            const handle = await fs.open(value, "r")
+            try {
+              const buffer = new Uint8Array(range.length)
+              const result = await handle.read(buffer, 0, range.length, range.offset)
+              return buffer.subarray(0, result.bytesRead)
+            } finally {
+              await handle.close()
+            }
+          },
+          true,
+        )
+        return { info, bytes }
+      }),
+    stat: (value) => stat(value, false),
+    list: (value) =>
+      Effect.gen(function* () {
+        const info = yield* stat(value, true)
+        if (info.type !== "directory") return yield* new WrongKind({ path: value, actual: info.type })
+        const entries = yield* attempt(value, () => fs.readdir(value, { withFileTypes: true }), true)
+        return entries.map((entry) => ({ name: entry.name, type: fileType(entry) }))
+      }),
+    write: (value, bytes) =>
+      attempt(value, async () => {
+        await fs.mkdir(path.dirname(value), { recursive: true })
+        await fs.writeFile(value, bytes)
+      }),
+    remove: (value) => attempt(value, () => fs.rm(value, { recursive: true, force: true })),
+    move: (from, to) =>
+      Effect.gen(function* () {
+        yield* stat(from, false)
+        const destination = yield* stat(to, false).pipe(
+          Effect.map((info) => (info.type === "directory" ? path.join(to, path.basename(from)) : to)),
+          Effect.catchIf(
+            (error) => error instanceof NotFound,
+            () => Effect.succeed(to),
+          ),
+        )
+        yield* attempt(from, () => fs.rename(from, destination))
+      }),
+    mkdir: (value) => attempt(value, () => fs.mkdir(value, { recursive: true }).then(() => undefined)),
+  }
+
+  return { spawner, overrides }
+}
+
+const stat = (value: string, follow: boolean) =>
+  attempt(value, () => (follow ? fs.stat(value) : fs.lstat(value)), true).pipe(
+    Effect.map((stats): FileInfo => ({ type: fileType(stats), size: stats.size, mtimeMs: stats.mtimeMs })),
+  )
+
+const fileType = (entry: { isFile(): boolean; isDirectory(): boolean; isSymbolicLink(): boolean }): FileType => {
+  if (entry.isFile()) return "file"
+  if (entry.isDirectory()) return "directory"
+  if (entry.isSymbolicLink()) return "symlink"
+  return "other"
+}
+
+function attempt<A>(value: string, run: () => Promise<A>): Effect.Effect<A, Failed>
+function attempt<A>(value: string, run: () => Promise<A>, missing: true): Effect.Effect<A, NotFound | Failed>
+function attempt<A>(value: string, run: () => Promise<A>, missing = false) {
+  return Effect.tryPromise({
+    try: run,
+    catch: (cause) =>
+      missing && isMissing(cause) ? new NotFound({ path: value }) : new Failed({ path: value, cause }),
+  })
+}
+
+const isMissing = (cause: unknown) =>
+  cause !== null &&
+  typeof cause === "object" &&
+  "code" in cause &&
+  (cause.code === "ENOENT" || cause.code === "ENOTDIR")
+
+export * as EnvironmentLocal from "./local"

packages/core/src/environment/memory.ts

@@ -90,7 +90,7 @@ export const makeMemoryDriver = (): MemoryDriver => {
         catch: (cause) => failed(value, cause),
       }),
     list: (value) => {
-      const target = resolveKey(value, false) ?? key(value)
+      const target = resolveKey(value, true) ?? key(value)
       const node = nodes.get(target)
       if (!node) return Effect.fail(new NotFound({ path: value }))
       if (node.type !== "directory") return Effect.fail(new WrongKind({ path: value, actual: node.type }))

packages/core/src/file-mutation.ts

@@ -5,6 +5,8 @@ import { Context, Effect, Layer } from "effect"
 import { KeyedMutex } from "./effect/keyed-mutex"
 import { FSUtil } from "@opencode-ai/util/fs-util"
 import { Bom } from "@opencode-ai/util/bom"
+import { Environment } from "./environment"
+import type { Files } from "./environment"
 
 export interface Target {
   readonly absolute: string
@@ -29,13 +31,36 @@ export interface WriteResult {
 }
 
 export interface Interface {
-  readonly write: (input: WriteInput) => Effect.Effect<WriteResult, FSUtil.Error>
+  /** Serialize a complete read/prepare/write mutation transaction by resolved path. */
+  readonly withLock: (
+    targets: ReadonlyArray<string>,
+  ) => <A, E, R>(effect: Effect.Effect<A, E, R>) => Effect.Effect<A, E, R>
+  readonly write: (input: WriteInput) => Effect.Effect<WriteResult, Environment.Failed>
   /** Write text while retaining an existing UTF-8 BOM and emitting at most one BOM. */
-  readonly writeTextPreservingBom: (input: TextWriteInput) => Effect.Effect<WriteResult, FSUtil.Error>
+  readonly writeTextPreservingBom: (
+    input: TextWriteInput,
+  ) => Effect.Effect<WriteResult, Environment.WrongKind | Environment.Failed>
 }
 
 export class Service extends Context.Service<Service, Interface>()("@opencode/FileMutation") {}
 
+export const readText = Effect.fn("FileMutation.readText")(function* (files: Files, target: string) {
+  return Bom.decodeBytes((yield* files.read(target)).bytes)
+})
+
+export const syncTextBom = Effect.fn("FileMutation.syncTextBom")(function* (
+  files: Files,
+  target: string,
+  bom: boolean,
+) {
+  const synced = Bom.syncBytes((yield* files.read(target)).bytes, bom)
+  if (synced.bytes) yield* files.write(target, synced.bytes)
+  return synced.text
+})
+
+/** Share transaction locks across Location graphs that address the same file. */
+const transactionLocks = KeyedMutex.makeUnsafe<string>()
+
 /**
  * Serialize file changes by absolute target. Conditional writes compare and
  * write under the same process-local lock so cooperating OpenCode mutations do
@@ -44,8 +69,12 @@ export class Service extends Context.Service<Service, Interface>()("@opencode/Fi
 const layer = Layer.effect(
   Service,
   Effect.gen(function* () {
-    const fs = yield* FSUtil.Service
+    const environment = yield* Environment.Service
     const locks = KeyedMutex.makeUnsafe<string>()
+    const withLock: Interface["withLock"] = (targets) => (effect) =>
+      [...new Set(targets.map(FSUtil.resolve))]
+        .sort()
+        .reduceRight((result, target) => transactionLocks.withLock(target)(result), effect)
     const withTargetLock =
       (target: Target) =>
       <A, E, R>(effect: Effect.Effect<A, E, R>) =>
@@ -61,8 +90,14 @@ const layer = Layer.effect(
     const write = Effect.fn("FileMutation.write")((input: WriteInput) =>
       withTargetLock(input.target)(
         Effect.gen(function* () {
-          const existed = yield* fs.exists(input.target.absolute)
-          yield* fs.writeWithDirs(input.target.absolute, input.content)
+          const existed = yield* environment.files.stat(input.target.absolute).pipe(
+            Effect.as(true),
+            Effect.catchTag("Environment.NotFound", () => Effect.succeed(false)),
+          )
+          yield* environment.files.write(
+            input.target.absolute,
+            typeof input.content === "string" ? new TextEncoder().encode(input.content) : input.content,
+          )
           return writeResult(input.target, existed)
         }),
       ),
@@ -72,23 +107,24 @@ const layer = Layer.effect(
       withTargetLock(input.target)(
         Effect.gen(function* () {
           const next = Bom.split(input.content)
-          const current = yield* fs
-            .readFile(input.target.absolute)
-            .pipe(Effect.catchReason("PlatformError", "NotFound", () => Effect.succeed(undefined)))
-          yield* fs.writeWithDirs(
+          const current = yield* environment.files.read(input.target.absolute, { offset: 0, length: 3 }).pipe(
+            Effect.map((result) => result.bytes),
+            Effect.catchTag("Environment.NotFound", () => Effect.succeed(undefined)),
+          )
+          yield* environment.files.write(
             input.target.absolute,
-            Bom.join(next.text, Boolean(current && Bom.has(current)) || next.bom),
+            new TextEncoder().encode(Bom.join(next.text, Boolean(current && Bom.has(current)) || next.bom)),
           )
           return writeResult(input.target, current !== undefined)
         }),
       ),
     )
 
-    return Service.of({ write, writeTextPreservingBom })
+    return Service.of({ withLock, write, writeTextPreservingBom })
   }),
 )
 
-export const node = makeLocationNode({ service: Service, layer, deps: [FSUtil.node] })
+export const node = makeLocationNode({ service: Service, layer, deps: [Environment.node] })
 
 /**
  * Deferred until the corresponding integrations exist.

packages/core/src/filesystem/location-watcher.ts

@@ -11,15 +11,6 @@ import { FSUtil } from "@opencode-ai/util/fs-util"
 import { Git } from "../git"
 import { Location } from "../location"
 import { Watcher } from "./watcher"
-import { Ignore } from "./ignore"
-import { Protected } from "./protected"
-
-function protecteds(dir: string) {
-  return Protected.paths().filter((item) => {
-    const relative = path.relative(dir, item)
-    return relative !== "" && !relative.startsWith("..") && !path.isAbsolute(relative)
-  })
-}
 
 export interface Interface {}
 
@@ -44,19 +35,6 @@ const layer = Layer.effect(
       const config = (yield* configService.entries())
         .filter((entry): entry is Document => entry.type === "document")
         .flatMap((item) => item.info.watcher?.ignore ?? [])
-      const home = Protected.isHome(location.directory)
-
-      if (!home && location.vcs) {
-        const updates = yield* watcher.subscribe({
-          path: location.directory,
-          type: "directory",
-          ignore: [...Ignore.PATTERNS, ...config, ...protecteds(location.directory)],
-        })
-        yield* updates.pipe(Stream.runForEach(publish), Effect.forkScoped)
-      }
-      if (home) {
-        yield* Effect.logInfo("location watcher skipped home directory", { directory: location.directory })
-      }
 
       if (location.vcs?.type === "git") {
         const resolved = (yield* git.repo.discover(location.directory))?.gitDirectory
@@ -64,10 +42,7 @@ const layer = Layer.effect(
           ? yield* fs.realPath(resolved).pipe(Effect.catch(() => Effect.succeed(resolved)))
           : undefined
         if (vcs && !config.includes(".git") && !config.includes(vcs) && (!resolved || !config.includes(resolved))) {
-          const ignore = (yield* fs.readDirectoryEntries(vcs).pipe(Effect.catch(() => Effect.succeed([])))).flatMap(
-            (entry) => (entry.name === "HEAD" ? [] : [entry.name]),
-          )
-          const updates = yield* watcher.subscribe({ path: vcs, type: "directory", ignore })
+          const updates = yield* watcher.subscribe({ path: path.join(vcs, "HEAD"), type: "file" })
           yield* updates.pipe(Stream.runForEach(publish), Effect.forkScoped)
         }
       }

packages/core/src/location-services.ts

@@ -8,6 +8,7 @@ import { LayerNode } from "@opencode-ai/util/effect/layer-node"
 import { Node } from "@opencode-ai/util/effect/app-node"
 import { Bus } from "./bus"
 import { FileMutation } from "./file-mutation"
+import { Environment } from "./environment"
 import { Formatter } from "./formatter"
 import { FileSystem } from "./filesystem"
 import { FileSystemSearch } from "./filesystem/search"
@@ -53,6 +54,7 @@ export { LocationServiceMap } from "./location-service-map"
 
 const locationServiceNodes = [
   Location.node,
+  Environment.node,
   Config.node,
   Agent.node,
   Command.node,

packages/core/src/plugin/internal.ts

@@ -16,6 +16,7 @@ import { ConfigReferencePlugin } from "../config/plugin/reference"
 import { ConfigSkillPlugin } from "../config/plugin/skill"
 import { ConfigWebSearchPlugin } from "../config/plugin/websearch"
 import { Bus } from "../bus"
+import { Environment } from "../environment"
 import { FileMutation } from "../file-mutation"
 import { Formatter } from "../formatter"
 import { Form } from "../form"
@@ -70,6 +71,7 @@ const services = Effect.fn("PluginInternal.services")(function* () {
   const config = yield* Config.Service
   const credential = yield* Credential.Service
   const bus = yield* Bus.Service
+  const environment = yield* Environment.Service
   const mutation = yield* FileMutation.Service
   const formatter = yield* Formatter.Service
   const filesystem = yield* FileSystem.Service
@@ -102,6 +104,7 @@ const services = Effect.fn("PluginInternal.services")(function* () {
     Context.make(Config.Service, config),
     Context.make(Credential.Service, credential),
     Context.make(Bus.Service, bus),
+    Context.make(Environment.Service, environment),
     Context.make(FileMutation.Service, mutation),
     Context.make(Formatter.Service, formatter),
     Context.make(FileSystem.Service, filesystem),

packages/core/src/plugin/supervisor.ts

@@ -14,6 +14,7 @@ import { Credential } from "../credential"
 import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
 import { httpClient } from "@opencode-ai/util/effect/app-node-platform"
 import { Bus } from "../bus"
+import { Environment } from "../environment"
 import { FileMutation } from "../file-mutation"
 import { Formatter } from "../formatter"
 import { FileSystem } from "../filesystem"
@@ -282,7 +283,9 @@ const layer = Layer.effect(
     })
     const updates = Stream.merge(
       config.changes().pipe(
-        Stream.filterEffect((update) => Effect.map(config.entries(), (entries) => isPluginSource(entries, update.path))),
+        Stream.filterEffect((update) =>
+          Effect.map(config.entries(), (entries) => isPluginSource(entries, update.path)),
+        ),
         Stream.merge(Stream.fromPubSub(configuredChanges)),
       ),
       bus.subscribe([Event.Updated, SdkPlugins.Updated]),
@@ -320,6 +323,7 @@ export const node = makeLocationNode({
     Config.node,
     Credential.node,
     Bus.node,
+    Environment.node,
     FileMutation.node,
     Formatter.node,
     FileSystem.node,

packages/core/src/ripgrep.ts

@@ -3,8 +3,9 @@ export * as Ripgrep from "./ripgrep"
 import { Context, Effect, Fiber, Layer, Schema, Stream } from "effect"
 import { ChildProcess } from "effect/unstable/process"
 import { Entry, Match } from "@opencode-ai/schema/filesystem"
-import { makeGlobalNode } from "@opencode-ai/util/effect/app-node"
-import { AppProcess, collectStream, waitForAbort } from "@opencode-ai/util/process"
+import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
+import { collectStream, waitForAbort } from "@opencode-ai/util/process"
+import { Environment } from "./environment"
 import { NonNegativeInt, PositiveInt, RelativePath } from "./schema"
 import { RipgrepBinary } from "./ripgrep/binary"
 
@@ -93,7 +94,7 @@ const isInvalidPattern = (stderr: string) =>
 const layer = Layer.effect(
   Service,
   Effect.gen(function* () {
-    const process = yield* AppProcess.Service
+    const environment = yield* Environment.Service
     const binary = yield* RipgrepBinary.Service
 
     const run = <A>(input: {
@@ -107,7 +108,8 @@ const layer = Layer.effect(
     }) => {
       const program = Effect.scoped(
         Effect.gen(function* () {
-          const handle = yield* process.spawn(
+          // Hosted environments will resolve rg through their driver image; the spawner is the execution seam.
+          const handle = yield* environment.spawner.spawn(
             ChildProcess.make(yield* binary.filepath, input.args, { cwd: input.cwd, extendEnv: true, stdin: "ignore" }),
           )
           const stderrFiber = yield* collectStream(handle.stderr, ERROR_BYTES).pipe(
@@ -275,4 +277,4 @@ const layer = Layer.effect(
   }),
 )
 
-export const node = makeGlobalNode({ service: Service, layer: layer, deps: [RipgrepBinary.node, AppProcess.node] })
+export const node = makeLocationNode({ service: Service, layer, deps: [Environment.node, RipgrepBinary.node] })

packages/core/src/session/execution/restart.ts

@@ -2,9 +2,14 @@ export * as SessionRestart from "./restart"
 
 import { Context, Effect, Layer } from "effect"
 import { makeGlobalNode } from "@opencode-ai/util/effect/app-node"
+import { Bus } from "../../bus"
+import { SessionEvent } from "../event"
 import { SessionExecution } from "../execution"
 import { SessionStore } from "../store"
 
+const CONTINUE_AFTER_SERVER_RESTART =
+  "The server restarted while you were working. Continue from where you left off without repeating completed work."
+
 export interface Interface {
   /**
    * Marks every execution active in this process for resumption by the next server start.
@@ -26,6 +31,7 @@ export const layer = Layer.effect(
   Effect.gen(function* () {
     const store = yield* SessionStore.Service
     const execution = yield* SessionExecution.Service
+    const bus = yield* Bus.Service
     return Service.of({
       suspendActiveSessions: Effect.gen(function* () {
         yield* store.suspend(yield* execution.active)
@@ -37,6 +43,11 @@ export const layer = Layer.effect(
           (sessionID) =>
             Effect.gen(function* () {
               if (!(yield* store.consumeSuspended(sessionID))) return
+              yield* bus.publish(SessionEvent.Synthetic, {
+                sessionID,
+                text: CONTINUE_AFTER_SERVER_RESTART,
+                description: "Continuing after restart",
+              })
               // Drain failures are already logged and durably recorded by the execution layer.
               yield* Effect.ignore(execution.resume(sessionID))
             }),
@@ -47,4 +58,8 @@ export const layer = Layer.effect(
   }),
 )
 
-export const node = makeGlobalNode({ service: Service, layer, deps: [SessionStore.node, SessionExecution.node] })
+export const node = makeGlobalNode({
+  service: Service,
+  layer,
+  deps: [SessionStore.node, SessionExecution.node, Bus.node],
+})

packages/core/src/shell.ts

@@ -6,9 +6,9 @@ import { ChildProcess } from "effect/unstable/process"
 import { produce } from "immer"
 import { Shell } from "@opencode-ai/schema/shell"
 import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
-import { AppProcess } from "@opencode-ai/util/process"
 import { Config } from "./config"
 import { Bus } from "./bus"
+import { Environment } from "./environment"
 import { Location } from "./location"
 import { Global } from "@opencode-ai/util/global"
 import { ShellSelect } from "./shell/select"
@@ -65,285 +65,284 @@ export interface Interface {
 
 export class Service extends Context.Service<Service, Interface>()("@opencode/Shell") {}
 
-export const layer = (options?: ShellSelect.Options) => Layer.effect(
-  Service,
-  Effect.gen(function* () {
-    const bus = yield* Bus.Service
-    const location = yield* Location.Service
-    const config = yield* Config.Service
-    const global = yield* Global.Service
-    const appProcess = yield* AppProcess.Service
-    const hooks = yield* PluginHooks.Service
-    const context = yield* Effect.context()
-    const runFork = Effect.runForkWith(context)
-    const sessions = new Map<string, Active>()
-    const exitOrder: string[] = []
+export const layer = (options?: ShellSelect.Options) =>
+  Layer.effect(
+    Service,
+    Effect.gen(function* () {
+      const bus = yield* Bus.Service
+      const location = yield* Location.Service
+      const config = yield* Config.Service
+      const global = yield* Global.Service
+      const environment = yield* Environment.Service
+      const hooks = yield* PluginHooks.Service
+      const context = yield* Effect.context()
+      const runFork = Effect.runForkWith(context)
+      const sessions = new Map<string, Active>()
+      const exitOrder: string[] = []
 
-    const outputDir = path.join(global.data, "shell", location.project.id)
-    const { mkdir, unlink } = yield* Effect.promise(() => import("fs/promises"))
-    const { createWriteStream, createReadStream } = yield* Effect.promise(() => import("fs"))
-    yield* Effect.promise(() => mkdir(outputDir, { recursive: true }))
+      const outputDir = path.join(global.data, "shell", location.project.id)
+      const { mkdir, unlink } = yield* Effect.promise(() => import("fs/promises"))
+      const { createWriteStream, createReadStream } = yield* Effect.promise(() => import("fs"))
+      yield* Effect.promise(() => mkdir(outputDir, { recursive: true }))
 
-    yield* Effect.addFinalizer(() =>
-      Effect.gen(function* () {
-        for (const session of sessions.values()) {
-          if (session.timeoutFiber) yield* Fiber.interrupt(session.timeoutFiber)
-          // Unblock waiters still pending at teardown; succeed is a no-op once already resolved.
-          yield* Deferred.fail(session.done, new NotFoundError({ id: Shell.ID.make(session.info.id) }))
+      yield* Effect.addFinalizer(() =>
+        Effect.gen(function* () {
+          for (const session of sessions.values()) {
+            if (session.timeoutFiber) yield* Fiber.interrupt(session.timeoutFiber)
+            // Unblock waiters still pending at teardown; succeed is a no-op once already resolved.
+            yield* Deferred.fail(session.done, new NotFoundError({ id: Shell.ID.make(session.info.id) }))
+          }
+          sessions.clear()
+          exitOrder.length = 0
+        }),
+      )
+
+      const require = Effect.fn("Shell.require")(function* (id: Shell.ID) {
+        const session = sessions.get(id)
+        if (!session) return yield* new NotFoundError({ id })
+        return session
+      })
+
+      const removeSession = Effect.fnUntraced(function* (id: Shell.ID) {
+        const session = sessions.get(id)
+        if (!session) return
+        sessions.delete(id)
+        const index = exitOrder.indexOf(id)
+        if (index !== -1) exitOrder.splice(index, 1)
+        if (session.timeoutFiber) yield* Fiber.interrupt(session.timeoutFiber)
+        // Unblock any wait still pending when the command is removed before it terminated.
+        yield* Deferred.fail(session.done, new NotFoundError({ id }))
+        yield* Effect.promise(() => unlink(session.file).catch(() => {}))
+        yield* bus.publish(Shell.Event.Deleted, { id })
+      })
+
+      const remove = Effect.fn("Shell.remove")(function* (id: Shell.ID) {
+        yield* require(id)
+        yield* removeSession(id)
+      })
+
+      const list = Effect.fn("Shell.list")(function* () {
+        return Array.from(sessions.values())
+          .filter((session) => session.info.status === "running")
+          .map((session) => session.info)
+      })
+
+      const get = Effect.fn("Shell.get")(function* (id: Shell.ID) {
+        return (yield* require(id)).info
+      })
+
+      const wait = Effect.fn("Shell.wait")(function* (id: Shell.ID) {
+        return yield* Deferred.await((yield* require(id)).done)
+      })
+
+      const timeout = Effect.fn("Shell.timeout")(function* (id: Shell.ID, duration: number) {
+        const session = yield* require(id)
+        if (session.info.status !== "running" || !session.timeout) return session.info
+        yield* session.timeout(duration)
+        return session.info
+      })
+
+      const resolve = () =>
+        config.entries().pipe(Effect.map((entries) => ShellSelect.preferred(Config.latest(entries, "shell"), options)))
+
+      const name = () => resolve().pipe(Effect.map(ShellSelect.name))
+
+      const output = Effect.fn("Shell.output")(function* (id: Shell.ID, input?: Shell.OutputInput) {
+        const session = yield* require(id)
+        const cursor = input?.cursor ?? 0
+        const limit = input?.limit ?? 65536
+        if (cursor >= session.size) return { output: "", cursor: session.size, size: session.size, truncated: false }
+        const start = Math.max(0, cursor)
+        const length = Math.min(limit, session.size - start)
+        const buffer = Buffer.alloc(length)
+        const bytesRead = yield* Effect.promise(
+          () =>
+            new Promise<number>((resolve) => {
+              const stream = createReadStream(session.file, { start, end: start + length - 1 })
+              let offset = 0
+              stream.on("data", (chunk: string | Buffer) => {
+                const bytes = Buffer.from(chunk)
+                bytes.copy(buffer, offset)
+                offset += bytes.length
+              })
+              stream.on("end", () => resolve(offset))
+              stream.on("error", () => resolve(0))
+            }),
+        )
+        return {
+          output: buffer.subarray(0, bytesRead).toString("utf8"),
+          cursor: start + bytesRead,
+          size: session.size,
+          truncated: false,
         }
-        sessions.clear()
-        exitOrder.length = 0
-      }),
-    )
+      })
 
-    const require = Effect.fn("Shell.require")(function* (id: Shell.ID) {
-      const session = sessions.get(id)
-      if (!session) return yield* new NotFoundError({ id })
-      return session
-    })
+      const create = Effect.fn("Shell.create")(function* <E = never, R = never>(
+        input: Shell.CreateInput,
+        before?: (input: ShellCreateBefore) => Effect.Effect<void, E, R>,
+      ) {
+        const invocation: ShellCreateBefore = {
+          command: input.command,
+          cwd: input.cwd ?? location.directory,
+          timeout: input.timeout,
+          shell: yield* resolve(),
+          env: {
+            ...process.env,
+            TERM: "xterm-256color",
+            OPENCODE_TERMINAL: "1",
+          },
+        }
+        yield* hooks.trigger("shell", "create.before", invocation)
+        if (before) yield* before(invocation)
 
-    const removeSession = Effect.fnUntraced(function* (id: Shell.ID) {
-      const session = sessions.get(id)
-      if (!session) return
-      sessions.delete(id)
-      const index = exitOrder.indexOf(id)
-      if (index !== -1) exitOrder.splice(index, 1)
-      if (session.timeoutFiber) yield* Fiber.interrupt(session.timeoutFiber)
-      // Unblock any wait still pending when the command is removed before it terminated.
-      yield* Deferred.fail(session.done, new NotFoundError({ id }))
-      yield* Effect.promise(() => unlink(session.file).catch(() => {}))
-      yield* bus.publish(Shell.Event.Deleted, { id })
-    })
+        const id = Shell.ID.ascending()
+        const args = ShellSelect.args(invocation.shell, invocation.command)
+        const file = path.join(outputDir, `${id}.out`)
 
-    const remove = Effect.fn("Shell.remove")(function* (id: Shell.ID) {
-      yield* require(id)
-      yield* removeSession(id)
-    })
+        const info: Info = {
+          id,
+          status: "running",
+          command: invocation.command,
+          cwd: invocation.cwd,
+          shell: invocation.shell,
+          file,
+          metadata: input.metadata ?? {},
+          time: { started: Date.now() },
+        }
 
-    const list = Effect.fn("Shell.list")(function* () {
-      return Array.from(sessions.values())
-        .filter((session) => session.info.status === "running")
-        .map((session) => session.info)
-    })
-
-    const get = Effect.fn("Shell.get")(function* (id: Shell.ID) {
-      return (yield* require(id)).info
-    })
-
-    const wait = Effect.fn("Shell.wait")(function* (id: Shell.ID) {
-      return yield* Deferred.await((yield* require(id)).done)
-    })
-
-    const timeout = Effect.fn("Shell.timeout")(function* (id: Shell.ID, duration: number) {
-      const session = yield* require(id)
-      if (session.info.status !== "running" || !session.timeout) return session.info
-      yield* session.timeout(duration)
-      return session.info
-    })
-
-    const resolve = () =>
-      config
-        .entries()
-        .pipe(Effect.map((entries) => ShellSelect.preferred(Config.latest(entries, "shell"), options)))
-
-    const name = () => resolve().pipe(Effect.map(ShellSelect.name))
-
-    const output = Effect.fn("Shell.output")(function* (id: Shell.ID, input?: Shell.OutputInput) {
-      const session = yield* require(id)
-      const cursor = input?.cursor ?? 0
-      const limit = input?.limit ?? 65536
-      if (cursor >= session.size) return { output: "", cursor: session.size, size: session.size, truncated: false }
-      const start = Math.max(0, cursor)
-      const length = Math.min(limit, session.size - start)
-      const buffer = Buffer.alloc(length)
-      const bytesRead = yield* Effect.promise(
-        () =>
-          new Promise<number>((resolve) => {
-            const stream = createReadStream(session.file, { start, end: start + length - 1 })
-            let offset = 0
-            stream.on("data", (chunk: string | Buffer) => {
-              const bytes = Buffer.from(chunk)
-              bytes.copy(buffer, offset)
-              offset += bytes.length
-            })
-            stream.on("end", () => resolve(offset))
-            stream.on("error", () => resolve(0))
-          }),
-      )
-      return {
-        output: buffer.subarray(0, bytesRead).toString("utf8"),
-        cursor: start + bytesRead,
-        size: session.size,
-        truncated: false,
-      }
-    })
-
-    const create = Effect.fn("Shell.create")(function* <E = never, R = never>(
-      input: Shell.CreateInput,
-      before?: (input: ShellCreateBefore) => Effect.Effect<void, E, R>,
-    ) {
-      const invocation: ShellCreateBefore = {
-        command: input.command,
-        cwd: input.cwd ?? location.directory,
-        timeout: input.timeout,
-        shell: yield* resolve(),
-        env: {
-          ...process.env,
-          TERM: "xterm-256color",
-          OPENCODE_TERMINAL: "1",
-        },
-      }
-      yield* hooks.trigger("shell", "create.before", invocation)
-      if (before) yield* before(invocation)
-
-      const id = Shell.ID.ascending()
-      const args = ShellSelect.args(invocation.shell, invocation.command)
-      const file = path.join(outputDir, `${id}.out`)
-
-      const info: Info = {
-        id,
-        status: "running",
-        command: invocation.command,
-        cwd: invocation.cwd,
-        shell: invocation.shell,
-        file,
-        metadata: input.metadata ?? {},
-        time: { started: Date.now() },
-      }
-
-      // Spawn via AppProcess and stream combined output to the file. The handle is scope-bound, so
-      // the managing fiber keeps its scope open until the command terminates (it awaits `done` at the
-      // end). `create` returns once `ready` resolves with the registered session.
-      const ready = Deferred.makeUnsafe<Active>()
-      runFork(
-        Effect.scoped(
-          Effect.gen(function* () {
-            const handle = yield* appProcess.spawn(
-              ChildProcess.make(invocation.shell, args, {
-                cwd: invocation.cwd,
-                env: invocation.env,
-                stdin: "ignore",
-                detached: process.platform !== "win32",
-                forceKillAfter: Duration.seconds(3),
-              }),
-            )
-            const session: Active = {
-              info: produce(info, (draft) => {
-                draft.pid = handle.pid
-              }),
-              file,
-              size: 0,
-              done: Deferred.makeUnsafe<Info, NotFoundError>(),
-            }
-            sessions.set(id, session)
-
-            const stream = createWriteStream(file)
-            const outputDone = Deferred.makeUnsafe<void>()
-            const pump = handle.all.pipe(
-              Stream.runForEach((chunk: Uint8Array) =>
-                Effect.sync(() => {
-                  stream.write(chunk)
-                  session.size += chunk.length
+        // Spawn through the Environment and stream combined output to the file. The handle is scope-bound, so
+        // the managing fiber keeps its scope open until the command terminates (it awaits `done` at the
+        // end). `create` returns once `ready` resolves with the registered session.
+        const ready = Deferred.makeUnsafe<Active>()
+        runFork(
+          Effect.scoped(
+            Effect.gen(function* () {
+              const handle = yield* environment.spawner.spawn(
+                ChildProcess.make(invocation.shell, args, {
+                  cwd: invocation.cwd,
+                  env: invocation.env,
+                  stdin: "ignore",
+                  detached: process.platform !== "win32",
+                  forceKillAfter: Duration.seconds(3),
                 }),
-              ),
-            )
-            runFork(
-              Effect.gen(function* () {
-                yield* pump.pipe(Effect.catch(() => Effect.void))
-                yield* Effect.promise(
-                  () =>
-                    new Promise<void>((resolve) => {
-                      stream.end(() => resolve())
-                    }),
-                )
-                yield* Deferred.succeed(outputDone, undefined)
-              }).pipe(Effect.catch(() => Deferred.succeed(outputDone, undefined))),
-            )
-            yield* Effect.promise(
-              () =>
-                new Promise<void>((resolve) => {
-                  stream.once("open", () => resolve())
-                  stream.once("error", () => resolve())
+              )
+              const session: Active = {
+                info: produce(info, (draft) => {
+                  draft.pid = handle.pid
                 }),
-            )
+                file,
+                size: 0,
+                done: Deferred.makeUnsafe<Info, NotFoundError>(),
+              }
+              sessions.set(id, session)
 
-            const finish = (status: Info["status"], exit?: number, beforeWait = Effect.void) =>
-              Effect.gen(function* () {
-                if (session.info.status !== "running") return
-                session.info = produce(session.info, (draft) => {
-                  draft.status = status
-                  if (exit !== undefined) draft.exit = exit
-                  draft.time.completed = Date.now()
-                })
-                yield* beforeWait
-                yield* Deferred.await(outputDone)
-                // Resolve waiters with the terminal Info before any retention eviction, so an evicted
-                // session still reports success rather than the removal NotFoundError. This runs before
-                // the timeout-fiber interrupt below, which on the timeout path would otherwise cancel
-                // this very fiber (finish is invoked by the timeout fiber) before waiters are resolved.
-                yield* Deferred.succeed(session.done, session.info)
-                yield* bus.publish(Shell.Event.Exited, {
-                  id,
-                  ...(exit !== undefined ? { exit } : {}),
-                  status,
-                })
-                exitOrder.push(id)
-                while (exitOrder.length > EXITED_LIMIT) {
-                  const oldest = exitOrder[0]
-                  if (!oldest) break
-                  yield* removeSession(Shell.ID.make(oldest))
-                }
-                // Cancel a pending timeout once the command exits on its own. Interrupting last avoids
-                // aborting finish when finish itself runs on the timeout fiber.
-                if (session.timeoutFiber) yield* Fiber.interrupt(session.timeoutFiber)
-              })
+              const stream = createWriteStream(file)
+              const outputDone = Deferred.makeUnsafe<void>()
+              const pump = handle.all.pipe(
+                Stream.runForEach((chunk: Uint8Array) =>
+                  Effect.sync(() => {
+                    stream.write(chunk)
+                    session.size += chunk.length
+                  }),
+                ),
+              )
+              runFork(
+                Effect.gen(function* () {
+                  yield* pump.pipe(Effect.catch(() => Effect.void))
+                  yield* Effect.promise(
+                    () =>
+                      new Promise<void>((resolve) => {
+                        stream.end(() => resolve())
+                      }),
+                  )
+                  yield* Deferred.succeed(outputDone, undefined)
+                }).pipe(Effect.catch(() => Deferred.succeed(outputDone, undefined))),
+              )
+              yield* Effect.promise(
+                () =>
+                  new Promise<void>((resolve) => {
+                    stream.once("open", () => resolve())
+                    stream.once("error", () => resolve())
+                  }),
+              )
 
-            session.timeout = (duration) =>
-              Effect.gen(function* () {
-                if (session.timeoutFiber) yield* Fiber.interrupt(session.timeoutFiber)
-                session.timeoutFiber = undefined
-                if (duration === 0 || session.info.status !== "running") return
-                session.timeoutFiber = runFork(
-                  Effect.sleep(Duration.millis(duration)).pipe(
-                    Effect.flatMap(() =>
-                      finish("timeout", undefined, handle.kill().pipe(Effect.catch(() => Effect.void))),
+              const finish = (status: Info["status"], exit?: number, beforeWait = Effect.void) =>
+                Effect.gen(function* () {
+                  if (session.info.status !== "running") return
+                  session.info = produce(session.info, (draft) => {
+                    draft.status = status
+                    if (exit !== undefined) draft.exit = exit
+                    draft.time.completed = Date.now()
+                  })
+                  yield* beforeWait
+                  yield* Deferred.await(outputDone)
+                  // Resolve waiters with the terminal Info before any retention eviction, so an evicted
+                  // session still reports success rather than the removal NotFoundError. This runs before
+                  // the timeout-fiber interrupt below, which on the timeout path would otherwise cancel
+                  // this very fiber (finish is invoked by the timeout fiber) before waiters are resolved.
+                  yield* Deferred.succeed(session.done, session.info)
+                  yield* bus.publish(Shell.Event.Exited, {
+                    id,
+                    ...(exit !== undefined ? { exit } : {}),
+                    status,
+                  })
+                  exitOrder.push(id)
+                  while (exitOrder.length > EXITED_LIMIT) {
+                    const oldest = exitOrder[0]
+                    if (!oldest) break
+                    yield* removeSession(Shell.ID.make(oldest))
+                  }
+                  // Cancel a pending timeout once the command exits on its own. Interrupting last avoids
+                  // aborting finish when finish itself runs on the timeout fiber.
+                  if (session.timeoutFiber) yield* Fiber.interrupt(session.timeoutFiber)
+                })
+
+              session.timeout = (duration) =>
+                Effect.gen(function* () {
+                  if (session.timeoutFiber) yield* Fiber.interrupt(session.timeoutFiber)
+                  session.timeoutFiber = undefined
+                  if (duration === 0 || session.info.status !== "running") return
+                  session.timeoutFiber = runFork(
+                    Effect.sleep(Duration.millis(duration)).pipe(
+                      Effect.flatMap(() =>
+                        finish("timeout", undefined, handle.kill().pipe(Effect.catch(() => Effect.void))),
+                      ),
+                      Effect.catch(() => Effect.void),
                     ),
-                    Effect.catch(() => Effect.void),
-                  ),
-                )
-              })
+                  )
+                })
 
-            yield* session.timeout(invocation.timeout)
+              yield* session.timeout(invocation.timeout)
 
-            runFork(
-              handle.exitCode.pipe(
-                Effect.flatMap((code) => finish("exited", code)),
-                Effect.catch(() => Effect.void),
-              ),
-            )
+              runFork(
+                handle.exitCode.pipe(
+                  Effect.flatMap((code) => finish("exited", code)),
+                  Effect.catch(() => Effect.void),
+                ),
+              )
 
-            yield* bus.publish(Shell.Event.Created, { info })
-            yield* Deferred.succeed(ready, session)
-            // Hold the handle's scope open until the command terminates; closing it earlier would
-            // release (kill) the process before its exit is observed.
-            yield* Deferred.await(session.done).pipe(Effect.catch(() => Effect.void))
-          }),
-        ).pipe(Effect.catch(() => Effect.void)),
-      )
+              yield* bus.publish(Shell.Event.Created, { info })
+              yield* Deferred.succeed(ready, session)
+              // Hold the handle's scope open until the command terminates; closing it earlier would
+              // release (kill) the process before its exit is observed.
+              yield* Deferred.await(session.done).pipe(Effect.catch(() => Effect.void))
+            }),
+          ).pipe(Effect.catch(() => Effect.void)),
+        )
 
-      const session = yield* Deferred.await(ready)
-      return session.info
-    })
+        const session = yield* Deferred.await(ready)
+        return session.info
+      })
 
-    return Service.of({ name, create, list, get, wait, timeout, output, remove })
-  }),
-)
+      return Service.of({ name, create, list, get, wait, timeout, output, remove })
+    }),
+  )
 
 export function configured(options?: ShellSelect.Options) {
   return makeLocationNode({
     service: Service,
     layer: layer(options),
-    deps: [Bus.node, Location.node, Config.node, Global.node, AppProcess.node, PluginHooks.node],
+    deps: [Bus.node, Location.node, Config.node, Global.node, Environment.node, PluginHooks.node],
   })
 }
 

packages/core/src/skill.ts

@@ -2,8 +2,7 @@ export * as Skill from "./skill"
 
 import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
 import path from "path"
-import { Context, Effect, Layer, Schema, Stream, Types } from "effect"
-import { FileSystem } from "@opencode-ai/schema/filesystem"
+import { Context, Effect, FiberMap, Layer, PubSub, Schema, Semaphore, Stream, Types } from "effect"
 import { Skill } from "@opencode-ai/schema/skill"
 import { Agent } from "./agent"
 import { ConfigMarkdown } from "./config/markdown"
@@ -13,6 +12,7 @@ import { Permission } from "./permission"
 import { AbsolutePath } from "./schema"
 import { SkillDiscovery } from "./skill/discovery"
 import { State } from "./state"
+import { Watcher } from "./filesystem/watcher"
 
 export const DirectorySource = Skill.DirectorySource
 export type DirectorySource = Skill.DirectorySource
@@ -81,6 +81,82 @@ const layer = Layer.effect(
     const discovery = yield* SkillDiscovery.Service
     const fs = yield* FSUtil.Service
     const bus = yield* Bus.Service
+    const watcher = yield* Watcher.Service
+    const cache = new Map<string, { skills: Info[]; paths: readonly string[] }>()
+    const watches = yield* FiberMap.make<string>()
+    const lock = Semaphore.makeUnsafe(1)
+    const changes = yield* PubSub.unbounded<string>()
+
+    const invalidate = Effect.fn("Skill.invalidateFromWatcher")(function* (file: string) {
+      const changed = yield* lock.withPermit(
+        Effect.gen(function* () {
+          const invalidated = Array.from(cache.entries()).filter(([, loaded]) =>
+            loaded.paths.some((item) => FSUtil.overlaps(item, file)),
+          )
+          if (invalidated.length === 0) return false
+          cache.clear()
+          yield* FiberMap.clear(watches)
+          yield* Effect.logInfo("skill cache invalidated", {
+            file,
+            sources: invalidated.map(([key]) => key),
+            skills: invalidated.flatMap(([, loaded]) => loaded.skills.map((skill) => skill.id)),
+          })
+          return true
+        }),
+      )
+      if (!changed) return
+      yield* bus.publish(Skill.Event.Updated, {}).pipe(Effect.asVoid)
+    })
+
+    yield* Stream.fromPubSub(changes).pipe(Stream.runForEach(invalidate), Effect.forkScoped({ startImmediately: true }))
+
+    const watch = Effect.fn("Skill.watch")(function* (directory: string, type: Watcher.WatchInput["type"]) {
+      const target = path.resolve(directory)
+      const updates = yield* watcher.subscribe(
+        type === "file" ? { path: target, type: "file" } : { path: target, type: "directory" },
+      )
+      yield* FiberMap.run(
+        watches,
+        `${type}:${target}`,
+        updates.pipe(Stream.runForEach((update) => PubSub.publish(changes, update.path).pipe(Effect.asVoid))),
+        {
+          onlyIfMissing: true,
+          startImmediately: true,
+        },
+      )
+    })
+
+    function firstMissing(target: string): Effect.Effect<string | undefined> {
+      const parent = path.dirname(target)
+      if (parent === target) return Effect.succeed(undefined)
+      return fs.isDir(parent).pipe(Effect.flatMap((exists) => (exists ? Effect.succeed(target) : firstMissing(parent))))
+    }
+
+    const watchDirectory: (directory: string) => Effect.Effect<string[]> = Effect.fn("Skill.watchDirectory")(function* (
+      directory: string,
+    ) {
+      const target = path.resolve(directory)
+      const resolved = yield* fs.realPath(directory).pipe(Effect.catch(() => Effect.succeed(undefined)))
+      if (resolved) {
+        yield* watch(resolved, "directory")
+        if (resolved !== target) {
+          yield* watch(target, "file")
+        }
+        return resolved === target ? [target] : [target, resolved]
+      }
+      const missing = yield* firstMissing(target)
+      if (missing) yield* watch(missing, "file")
+      if (
+        yield* fs.realPath(directory).pipe(
+          Effect.as(true),
+          Effect.catch(() => Effect.succeed(false)),
+        )
+      ) {
+        if (missing) yield* FiberMap.remove(watches, `file:${path.resolve(missing)}`)
+        return yield* watchDirectory(directory)
+      }
+      return [target]
+    })
 
     const state = State.create<Data, Draft>({
       name: "skill",
@@ -92,7 +168,10 @@ const layer = Layer.effect(
         },
         list: () => draft.sources as Source[],
       }),
-      finalize: () => bus.publish(Skill.Event.Updated, {}).pipe(Effect.asVoid),
+      finalize: () =>
+        lock
+          .withPermit(FiberMap.clear(watches).pipe(Effect.andThen(Effect.sync(() => cache.clear())), Effect.asVoid))
+          .pipe(Effect.andThen(bus.publish(Skill.Event.Updated, {})), Effect.asVoid),
     })
 
     const load = Effect.fn("Skill.load")(function* (source: Source) {
@@ -104,14 +183,22 @@ const layer = Layer.effect(
           directories: [],
           skills: [source.skill.id],
         })
-        return { skills: [source.skill], directories: [] }
+        return { skills: [source.skill], paths: [] }
       }
       const directories = source.type === "directory" ? [source.path] : yield* discovery.pull(source.url)
+      const roots = (yield* Effect.forEach(directories, watchDirectory)).flat()
+      const paths = [...roots]
       for (const directory of directories) {
         const files = yield* fs
           .scan("{*.md,**/SKILL.md}", { cwd: directory, absolute: true, include: "file", symlink: true, dot: true })
           .pipe(Effect.catch(() => Effect.succeed([] as string[])))
         for (const filepath of files.toSorted()) {
+          const resolved = yield* fs.realPath(filepath).pipe(Effect.catch(() => Effect.succeed(filepath)))
+          if (!roots.some((root) => FSUtil.contains(root, resolved))) {
+            const external = path.dirname(resolved)
+            paths.push(external)
+            yield* watch(external, "directory")
+          }
           const content = yield* fs.readFileStringSafe(filepath).pipe(Effect.catch(() => Effect.succeed(undefined)))
           if (!content) continue
           const markdown = ConfigMarkdown.parseOption(content)
@@ -139,38 +226,22 @@ const layer = Layer.effect(
         directories,
         skills: skills.map((skill) => skill.id),
       })
-      return { skills, directories }
+      return { skills, paths }
     })
 
-    const cache = new Map<string, { skills: Info[]; directories: readonly string[] }>()
-    const invalidate = Effect.fn("Skill.invalidateFromWatcher")(function* (file: string) {
-      const invalidated = Array.from(cache.entries()).filter(([, loaded]) =>
-        loaded.directories.some((directory) => FSUtil.contains(directory, file)),
-      )
-      if (invalidated.length === 0) return
-      for (const [key] of invalidated) cache.delete(key)
-      yield* Effect.logInfo("skill cache invalidated", {
-        file,
-        sources: invalidated.map(([key]) => key),
-        skills: invalidated.flatMap(([, loaded]) => loaded.skills.map((skill) => skill.id)),
-      })
-      yield* bus.publish(Skill.Event.Updated, {}).pipe(Effect.asVoid)
-    })
-
-    yield* bus.subscribe(FileSystem.Event.Changed).pipe(
-      Stream.runForEach((event) => invalidate(event.data.file)),
-      Effect.forkScoped({ startImmediately: true }),
-    )
-
     const list = Effect.fn("Skill.list")(function* () {
-      const skills = new Map<ID, Info>()
-      for (const source of state.get().sources) {
-        const key = Source.key(source)
-        const loaded = cache.get(key) ?? (yield* load(source))
-        cache.set(key, loaded)
-        for (const skill of loaded.skills) skills.set(skill.id, skill)
-      }
-      return Array.from(skills.values())
+      return yield* lock.withPermit(
+        Effect.gen(function* () {
+          const skills = new Map<ID, Info>()
+          for (const source of state.get().sources) {
+            const key = Source.key(source)
+            const loaded = cache.get(key) ?? (yield* load(source))
+            cache.set(key, loaded)
+            for (const skill of loaded.skills) skills.set(skill.id, skill)
+          }
+          return Array.from(skills.values())
+        }),
+      )
     })
 
     return Service.of({
@@ -187,5 +258,5 @@ const layer = Layer.effect(
 export const node = makeLocationNode({
   service: Service,
   layer,
-  deps: [SkillDiscovery.node, FSUtil.node, Bus.node],
+  deps: [SkillDiscovery.node, FSUtil.node, Bus.node, Watcher.node],
 })

packages/core/src/tool.ts

@@ -118,13 +118,12 @@ const layer = Layer.effect(
         yield* hooks.trigger("tool", "execute.after", afterEvent)
         return yield* afterEvent.error
       }
-      const content = yield* normalizeImages(execution.value.content)
       const afterEvent: PluginHooks.Domains["tool"]["execute.after"] = {
         ...base,
         status: "completed",
         result: {
           ...(execution.value.output === undefined ? {} : { output: execution.value.output }),
-          content: content.length > 0 ? content : execution.value.content,
+          content: execution.value.content,
           ...(execution.value.metadata === undefined ? {} : { metadata: execution.value.metadata }),
         },
       }

packages/core/src/tool/plugin/edit.ts

@@ -11,9 +11,11 @@ import { ToolFailure } from "@opencode-ai/ai"
 import { FileDiff } from "@opencode-ai/schema/file-diff"
 import { Bom } from "@opencode-ai/util/bom"
 import { Effect, Schema } from "effect"
+import path from "path"
+import { Environment } from "../../environment"
 import { FileMutation } from "../../file-mutation"
 import { Formatter } from "../../formatter"
-import { FSUtil } from "@opencode-ai/util/fs-util"
+import { Location } from "../../location"
 import { LocationMutation } from "../../location-mutation"
 import { Permission } from "../../permission"
 import { fileDiff } from "./file-diff"
@@ -109,9 +111,10 @@ export const Plugin = {
   id: "opencode.tool.edit",
   effect: Effect.fn("EditTool.Plugin")(function* (ctx: PluginContext) {
     const mutation = yield* LocationMutation.Service
-    const files = yield* FileMutation.Service
+    const fileMutation = yield* FileMutation.Service
+    const environment = yield* Environment.Service
     const formatter = yield* Formatter.Service
-    const fs = yield* FSUtil.Service
+    const location = yield* Location.Service
     const permission = yield* Permission.Service
 
     yield* ctx.tool
@@ -152,17 +155,16 @@ export const Plugin = {
                 })
               }
 
-              const info = yield* fs
-                .stat(target.absolute)
-                .pipe(
-                  Effect.catchReason("PlatformError", "NotFound", () =>
-                    Effect.fail(new ToolFailure({ message: `File not found: ${input.path}` })),
-                  ),
-                )
-              if (info.type === "Directory") {
-                return yield* new ToolFailure({ message: `Path is a directory, not a file: ${input.path}` })
-              }
-              const original = yield* Bom.readFile(fs, target.absolute)
+              const original = yield* FileMutation.readText(environment.files, target.absolute).pipe(
+                Effect.catchTag("Environment.NotFound", () =>
+                  Effect.fail(new ToolFailure({ message: `File not found: ${input.path}` })),
+                ),
+                Effect.catchTag("Environment.WrongKind", (error) =>
+                  error.actual === "directory"
+                    ? Effect.fail(new ToolFailure({ message: `Path is a directory, not a file: ${input.path}` }))
+                    : Effect.fail(new ToolFailure({ message: `Unable to edit ${input.path}`, error })),
+                ),
+              )
               const source = original.text
               const ending = source.includes(crlf) ? crlf : "\n"
               const oldString = input.oldString.replaceAll(crlf, "\n").replaceAll("\n", ending)
@@ -204,19 +206,20 @@ export const Plugin = {
                 })
               }
               const replacementBom = replaced.startsWith("\uFEFF")
-              const result = yield* files.write({
+              const result = yield* fileMutation.write({
                 target,
                 content: Bom.join(replaced, original.bom || replacementBom),
               })
               const bom = original.bom || replacementBom
               const formatted = (yield* formatter.file(target.absolute))
-                ? yield* Bom.syncFile(fs, target.absolute, bom)
-                : (yield* Bom.readFile(fs, target.absolute)).text
+                ? yield* FileMutation.syncTextBom(environment.files, target.absolute, bom)
+                : (yield* FileMutation.readText(environment.files, target.absolute)).text
               return {
                 files: [fileDiff(result.resource, source, formatted)],
                 replacements,
               } satisfies Output
             }).pipe(
+              fileMutation.withLock([path.resolve(location.directory, input.path)]),
               Effect.map((output) => ({
                 output,
                 content: `Edited ${output.files[0]?.file} (${output.replacements} replacement${output.replacements === 1 ? "" : "s"})`,

packages/core/src/tool/plugin/glob.ts

@@ -4,8 +4,8 @@ import { ToolFailure } from "@opencode-ai/ai"
 import type { Context as PluginContext } from "@opencode-ai/plugin/effect/plugin"
 import { Effect, Schema } from "effect"
 import path from "path"
+import { Environment } from "../../environment"
 import { FileSystem } from "../../filesystem"
-import { FSUtil } from "@opencode-ai/util/fs-util"
 import { Location } from "../../location"
 import { LocationMutation } from "../../location-mutation"
 import { Ripgrep } from "../../ripgrep"
@@ -42,7 +42,7 @@ export const toModelContent = (entries: EncodedOutput, truncated = false) => {
 export const Plugin = {
   id: "opencode.tool.glob",
   effect: Effect.fn("GlobTool.Plugin")(function* (ctx: PluginContext) {
-    const fs = yield* FSUtil.Service
+    const environment = yield* Environment.Service
     const ripgrep = yield* Ripgrep.Service
     const location = yield* Location.Service
     const mutation = yield* LocationMutation.Service
@@ -82,22 +82,20 @@ export const Plugin = {
                 agent: context.agent,
                 source,
               })
-              const info = yield* fs
-                .stat(target.absolute)
-                .pipe(
-                  Effect.catchReason("PlatformError", "NotFound", () =>
-                    Effect.fail(new ToolFailure({ message: `Search path does not exist: ${searchPath ?? "."}` })),
-                  ),
-                )
-              if (info.type !== "Directory")
+              const type = yield* Environment.typeFollowing(environment.files, target.absolute).pipe(
+                Effect.catchTag("Environment.NotFound", () =>
+                  Effect.fail(new ToolFailure({ message: `Search path does not exist: ${searchPath ?? "."}` })),
+                ),
+              )
+              if (type !== "directory")
                 return yield* Effect.fail(
                   new ToolFailure({ message: `Search path is not a directory: ${searchPath ?? "."}` }),
                 )
-              const root = path.resolve(location.directory, searchPath ?? ".")
+              const root = target.absolute
               const limit = input.limit ?? FileSystem.DEFAULT_SEARCH_LIMIT
               const entries = yield* ripgrep
                 .glob({
-                  cwd: target.absolute,
+                  cwd: root,
                   pattern: input.pattern,
                   limit: limit + 1,
                 })

packages/core/src/tool/plugin/grep.ts

@@ -4,8 +4,8 @@ import type { Context as PluginContext } from "@opencode-ai/plugin/effect/plugin
 import { ToolFailure } from "@opencode-ai/ai"
 import { Effect, Schema } from "effect"
 import path from "path"
+import { Environment } from "../../environment"
 import { FileSystem } from "../../filesystem"
-import { FSUtil } from "@opencode-ai/util/fs-util"
 import { Location } from "../../location"
 import { LocationMutation } from "../../location-mutation"
 import { Permission } from "../../permission"
@@ -15,11 +15,11 @@ import { RelativePath } from "../../schema"
 export const name = "grep"
 
 export const Input = Schema.Struct({
-  pattern: FileSystem.GrepInput.fields.pattern.check(
-    Schema.isMinLength(1, { message: "Pattern must not be empty" }),
-  ).annotate({
-    description: "Regular expression to search for in file contents (ripgrep syntax)",
-  }),
+  pattern: FileSystem.GrepInput.fields.pattern
+    .check(Schema.isMinLength(1, { message: "Pattern must not be empty" }))
+    .annotate({
+      description: "Regular expression to search for in file contents (ripgrep syntax)",
+    }),
   path: Schema.optionalKey(RelativePath).annotate({
     description: "File or directory to search. Defaults to the current working directory.",
   }),
@@ -58,7 +58,7 @@ export const toModelContent = (matches: EncodedOutput, truncated = false) => {
 export const Plugin = {
   id: "opencode.tool.grep",
   effect: Effect.fn("GrepTool.Plugin")(function* (ctx: PluginContext) {
-    const fs = yield* FSUtil.Service
+    const environment = yield* Environment.Service
     const ripgrep = yield* Ripgrep.Service
     const location = yield* Location.Service
     const mutation = yield* LocationMutation.Service
@@ -66,104 +66,100 @@ export const Plugin = {
 
     yield* ctx.tool
       .transform((draft) =>
-        draft.add(
-          ({
-            name,
-            options: { codemode: false },
-            description:
-              "Search file contents using regular expressions. Use it to locate specific code, symbols, or text patterns, and narrow searches with `path` or `include`. Returns matching file paths, line numbers, and line previews.",
-            input: Input,
-            output: Output,
-            execute: (input, context) =>
-              Effect.gen(function* () {
-                const source = { type: "tool" as const, messageID: context.messageID, id: context.id }
-                const target = yield* mutation.resolve({ path: input.path ?? "." })
-                if (target.externalDirectory)
-                  yield* permission.assert({
-                    ...LocationMutation.externalDirectoryPermission(target.externalDirectory),
-                    sessionID: context.sessionID,
-                    agent: context.agent,
-                    source,
-                  })
+        draft.add({
+          name,
+          options: { codemode: false },
+          description:
+            "Search file contents using regular expressions. Use it to locate specific code, symbols, or text patterns, and narrow searches with `path` or `include`. Returns matching file paths, line numbers, and line previews.",
+          input: Input,
+          output: Output,
+          execute: (input, context) =>
+            Effect.gen(function* () {
+              const source = { type: "tool" as const, messageID: context.messageID, id: context.id }
+              const target = yield* mutation.resolve({ path: input.path ?? "." })
+              if (target.externalDirectory)
                 yield* permission.assert({
-                  action: name,
-                  resources: [input.pattern],
-                  save: ["*"],
-                  metadata: {
-                    root: ".",
-                    path: input.path,
-                    include: input.include,
-                    limit: input.limit,
-                  },
+                  ...LocationMutation.externalDirectoryPermission(target.externalDirectory),
                   sessionID: context.sessionID,
                   agent: context.agent,
                   source,
                 })
-                const root = path.resolve(location.directory, input.path ?? ".")
-                const info = yield* fs
-                  .stat(root)
-                  .pipe(
-                    Effect.catchReason("PlatformError", "NotFound", () =>
-                      Effect.fail(new ToolFailure({ message: `Search path does not exist: ${input.path ?? "."}` })),
-                    ),
-                  )
-                const cwd = info?.type === "Directory" ? root : path.dirname(root)
-                const limit = input.limit ?? FileSystem.DEFAULT_SEARCH_LIMIT
-                const matches = yield* ripgrep
-                  .grep({
-                    cwd,
-                    pattern: input.pattern,
-                    file: info?.type === "File" ? path.basename(root) : undefined,
-                    include: input.include,
-                    limit: limit + 1,
-                  })
-                  .pipe(
-                    Effect.timeoutOrElse({
-                      duration: FileSystem.DEFAULT_SEARCH_TIMEOUT_MS,
-                      orElse: () =>
-                        Effect.fail(
-                          new ToolFailure({
-                            message: `Search timed out after ${FileSystem.DEFAULT_SEARCH_TIMEOUT_MS / 1_000} seconds. Consider using a more specific path or pattern.`,
-                          }),
-                        ),
-                    }),
-                    Effect.map((result) =>
-                      result.map((match) =>
-                        FileSystem.Match.make({
-                          ...match,
-                          entry: FileSystem.Entry.make({
-                            ...match.entry,
-                            path: RelativePath.make(
-                              path.relative(location.directory, path.resolve(cwd, match.entry.path)),
-                            ),
-                          }),
+              yield* permission.assert({
+                action: name,
+                resources: [input.pattern],
+                save: ["*"],
+                metadata: {
+                  root: ".",
+                  path: input.path,
+                  include: input.include,
+                  limit: input.limit,
+                },
+                sessionID: context.sessionID,
+                agent: context.agent,
+                source,
+              })
+              const root = target.absolute
+              const type = yield* Environment.typeFollowing(environment.files, root).pipe(
+                Effect.catchTag("Environment.NotFound", () =>
+                  Effect.fail(new ToolFailure({ message: `Search path does not exist: ${input.path ?? "."}` })),
+                ),
+              )
+              const cwd = type === "directory" ? root : path.dirname(root)
+              const limit = input.limit ?? FileSystem.DEFAULT_SEARCH_LIMIT
+              const matches = yield* ripgrep
+                .grep({
+                  cwd,
+                  pattern: input.pattern,
+                  file: type === "file" ? path.basename(root) : undefined,
+                  include: input.include,
+                  limit: limit + 1,
+                })
+                .pipe(
+                  Effect.timeoutOrElse({
+                    duration: FileSystem.DEFAULT_SEARCH_TIMEOUT_MS,
+                    orElse: () =>
+                      Effect.fail(
+                        new ToolFailure({
+                          message: `Search timed out after ${FileSystem.DEFAULT_SEARCH_TIMEOUT_MS / 1_000} seconds. Consider using a more specific path or pattern.`,
                         }),
                       ),
+                  }),
+                  Effect.map((result) =>
+                    result.map((match) =>
+                      FileSystem.Match.make({
+                        ...match,
+                        entry: FileSystem.Entry.make({
+                          ...match.entry,
+                          path: RelativePath.make(
+                            path.relative(location.directory, path.resolve(cwd, match.entry.path)),
+                          ),
+                        }),
+                      }),
                     ),
-                  )
-                return { matches: matches.slice(0, limit), truncated: matches.length > limit }
-              }).pipe(
-                Effect.map((result) => ({
-                  output: result.matches,
-                  content: toModelContent(
-                    result.matches.map((match) => ({
-                      ...match,
-                      entry: { ...match.entry, path: path.resolve(location.directory, match.entry.path) },
-                    })),
-                    result.truncated,
                   ),
-                  metadata: { matches: result.matches.length, truncated: result.truncated },
-                })),
-                Effect.mapError((error) =>
-                  error instanceof ToolFailure
-                    ? error
-                    : error instanceof Ripgrep.InvalidPatternError
-                      ? new ToolFailure({ message: `Invalid regex pattern: ${error.message}` })
-                    : new ToolFailure({ message: `Unable to grep for ${input.pattern}`, error }),
+                )
+              return { matches: matches.slice(0, limit), truncated: matches.length > limit }
+            }).pipe(
+              Effect.map((result) => ({
+                output: result.matches,
+                content: toModelContent(
+                  result.matches.map((match) => ({
+                    ...match,
+                    entry: { ...match.entry, path: path.resolve(location.directory, match.entry.path) },
+                  })),
+                  result.truncated,
                 ),
+                metadata: { matches: result.matches.length, truncated: result.truncated },
+              })),
+              Effect.mapError((error) =>
+                error instanceof ToolFailure
+                  ? error
+                  : error instanceof Ripgrep.InvalidPatternError
+                    ? new ToolFailure({ message: `Invalid regex pattern: ${error.message}` })
+                    : new ToolFailure({ message: `Unable to grep for ${input.pattern}`, error }),
               ),
-          }),
-        ),
+            ),
+        }),
       )
       .pipe(Effect.orDie)
   }),

packages/core/src/tool/plugin/patch.ts

@@ -4,12 +4,13 @@ import type { Context as PluginContext } from "@opencode-ai/plugin/effect/plugin
 import { ToolFailure } from "@opencode-ai/ai"
 import { FileDiff } from "@opencode-ai/schema/file-diff"
 import { createTwoFilesPatch, diffLines } from "diff"
-import { Effect, Schema } from "effect"
-import { PlatformError } from "effect/PlatformError"
+import { Effect, Result, Schema } from "effect"
 import path from "path"
 import { Bom } from "@opencode-ai/util/bom"
 import { FSUtil } from "@opencode-ai/util/fs-util"
+import { Environment } from "../../environment"
 import { Formatter } from "../../formatter"
+import { FileMutation } from "../../file-mutation"
 import { Location } from "../../location"
 import { Patch } from "@opencode-ai/util/patch"
 import { Permission } from "../../permission"
@@ -44,7 +45,13 @@ export const toModelOutput = (output: Output) =>
   ].join("\n")
 
 type Prepared =
-  | (Extract<Patch.Hunk, { readonly type: "add" | "delete" }> & {
+  | (Extract<Patch.Hunk, { readonly type: "add" }> & {
+      readonly target: Target
+      readonly content: string
+      readonly before: string
+      readonly after: string
+    })
+  | (Extract<Patch.Hunk, { readonly type: "delete" }> & {
       readonly target: Target
       readonly before: string
       readonly after: string
@@ -69,7 +76,8 @@ interface Target {
 export const Plugin = {
   id: "opencode.tool.patch",
   effect: Effect.fn("PatchTool.Plugin")(function* (ctx: PluginContext) {
-    const fs = yield* FSUtil.Service
+    const environment = yield* Environment.Service
+    const mutation = yield* FileMutation.Service
     const formatter = yield* Formatter.Service
     const location = yield* Location.Service
     const permission = yield* Permission.Service
@@ -84,6 +92,13 @@ export const Plugin = {
           output: Output,
           execute: (input, context) => {
             const applied: Array<typeof Applied.Type> = []
+            const parsed = Patch.parse(input.patchText)
+            const lockTargets = Result.isSuccess(parsed)
+              ? parsed.success.flatMap((hunk) => [
+                  path.resolve(location.directory, hunk.path),
+                  ...(hunk.type === "update" && hunk.movePath ? [path.resolve(location.directory, hunk.movePath)] : []),
+                ])
+              : []
             const fail = (operation: string, error: unknown) => {
               const completed = applied.map((item) => item.resource).join(", ")
               return new ToolFailure({
@@ -97,7 +112,7 @@ export const Plugin = {
                 id: context.id,
               }
               if (!input.patchText) return yield* new ToolFailure({ message: "patchText is required" })
-              const hunks = yield* Effect.fromResult(Patch.parse(input.patchText)).pipe(
+              const hunks = yield* Effect.fromResult(parsed).pipe(
                 Effect.mapError((error) => new ToolFailure({ message: `patch verification failed: ${error.message}` })),
               )
               if (hunks.length === 0) {
@@ -125,18 +140,19 @@ export const Plugin = {
                     })
                   }
                   if (hunk.type === "add") {
+                    const content =
+                      hunk.contents.endsWith("\n") || hunk.contents === "" ? hunk.contents : `${hunk.contents}\n`
                     prepared.push({
                       ...hunk,
                       target,
+                      content,
                       before: "",
-                      after: Bom.split(
-                        hunk.contents.endsWith("\n") || hunk.contents === "" ? hunk.contents : `${hunk.contents}\n`,
-                      ).text,
+                      after: Bom.split(content).text,
                     })
                     return
                   }
                   if (hunk.type === "delete") {
-                    const content = yield* Bom.readFile(fs, target.absolute).pipe(
+                    const content = yield* FileMutation.readText(environment.files, target.absolute).pipe(
                       Effect.mapError(
                         (error) =>
                           new ToolFailure({
@@ -151,20 +167,7 @@ export const Plugin = {
                   const original =
                     previous ??
                     (yield* Effect.gen(function* () {
-                      const stats = yield* fs.stat(target.absolute).pipe(
-                        Effect.mapError(
-                          (error) =>
-                            new ToolFailure({
-                              message: `patch verification failed: Failed to read file to update ${target.absolute}: ${errorMessage(error)}`,
-                            }),
-                        ),
-                      )
-                      if (stats.type === "Directory") {
-                        return yield* new ToolFailure({
-                          message: `patch verification failed: Failed to read file to update ${target.absolute}: path is a directory`,
-                        })
-                      }
-                      const content = yield* Bom.readFile(fs, target.absolute).pipe(
+                      const content = yield* FileMutation.readText(environment.files, target.absolute).pipe(
                         Effect.mapError(
                           (error) =>
                             new ToolFailure({
@@ -233,13 +236,8 @@ export const Plugin = {
                 (change) =>
                   Effect.gen(function* () {
                     if (change.type === "add") {
-                      yield* fs
-                        .writeWithDirs(
-                          change.target.absolute,
-                          change.contents.endsWith("\n") || change.contents === ""
-                            ? change.contents
-                            : `${change.contents}\n`,
-                        )
+                      yield* environment.files
+                        .write(change.target.absolute, new TextEncoder().encode(change.content))
                         .pipe(Effect.mapError((error) => fail(`Failed to write ${change.target.resource}`, error)))
                       applied.push({
                         type: change.type,
@@ -249,7 +247,7 @@ export const Plugin = {
                       return
                     }
                     if (change.type === "delete") {
-                      yield* fs
+                      yield* environment.files
                         .remove(change.target.absolute)
                         .pipe(Effect.mapError((error) => fail(`Failed to delete ${change.target.resource}`, error)))
                       applied.push({
@@ -261,10 +259,10 @@ export const Plugin = {
                     }
                     if (change.moveTarget) {
                       const moveTarget = change.moveTarget
-                      yield* fs
-                        .writeWithDirs(moveTarget.absolute, change.content)
+                      yield* environment.files
+                        .write(moveTarget.absolute, new TextEncoder().encode(change.content))
                         .pipe(Effect.mapError((error) => fail(`Failed to write ${moveTarget.resource}`, error)))
-                      yield* fs
+                      yield* environment.files
                         .remove(change.target.absolute)
                         .pipe(
                           Effect.mapError((error) =>
@@ -278,8 +276,8 @@ export const Plugin = {
                       })
                       return
                     }
-                    yield* fs
-                      .writeWithDirs(change.target.absolute, change.content)
+                    yield* environment.files
+                      .write(change.target.absolute, new TextEncoder().encode(change.content))
                       .pipe(Effect.mapError((error) => fail(`Failed to write ${change.target.resource}`, error)))
                     applied.push({
                       type: change.type,
@@ -294,13 +292,13 @@ export const Plugin = {
                 [...new Set(applied.filter((item) => item.type !== "delete").map((item) => item.target))],
                 (target) =>
                   Effect.gen(function* () {
-                    const current = yield* Bom.readFile(fs, target).pipe(
+                    const current = yield* FileMutation.readText(environment.files, target).pipe(
                       Effect.mapError((error) => fail(`Failed to read ${target}`, error)),
                     )
                     formatted.set(
                       target,
                       (yield* formatter.file(target))
-                        ? yield* Bom.syncFile(fs, target, current.bom).pipe(
+                        ? yield* FileMutation.syncTextBom(environment.files, target, current.bom).pipe(
                             Effect.mapError((error) => fail(`Failed to sync ${target}`, error)),
                           )
                         : current.text,
@@ -315,6 +313,7 @@ export const Plugin = {
               })
               return { applied, files }
             }).pipe(
+              mutation.withLock(lockTargets),
               Effect.map((output) => ({
                 output,
                 content: toModelOutput(output),
@@ -345,10 +344,10 @@ export const Plugin = {
 }
 
 function errorMessage(error: unknown) {
-  if (error instanceof PlatformError) {
-    if (error.reason._tag === "NotFound") return "file does not exist"
-    return error.reason.description ?? error.reason.message
-  }
+  if (error instanceof Environment.NotFound) return "file does not exist"
+  if (error instanceof Environment.WrongKind)
+    return error.actual === "directory" ? "path is a directory" : `path is ${error.actual}`
+  if (error instanceof Environment.Failed) return errorMessage(error.cause)
   return error instanceof Error ? error.message : String(error)
 }
 

packages/core/src/tool/plugin/read.ts

@@ -11,6 +11,7 @@ import { Permission } from "../../permission"
 import { SessionInstructions } from "../../session/instructions"
 import { AbsolutePath } from "../../schema"
 import { ReadToolFileSystem } from "../read-filesystem"
+import { Environment } from "../../environment"
 
 export const name = "read"
 const FILENAME = "AGENTS.md"
@@ -72,16 +73,12 @@ export const Plugin = {
                 agent: context.agent,
                 source,
               })
-              const type = yield* reader
-                .inspect(absolute)
-                .pipe(Effect.catchReason("PlatformError", "NotFound", () => missing(input.path, target.absolute)))
-              const content =
-                type === "directory"
-                  ? yield* reader.list(absolute, { offset: input.offset, limit: input.limit })
-                  : yield* reader.read(absolute, resource, {
-                      offset: input.offset,
-                      limit: input.limit,
-                    })
+              const content = yield* reader.read(absolute, resource, { offset: input.offset, limit: input.limit }).pipe(
+                Effect.catchIf(
+                  (error) => error instanceof Environment.NotFound,
+                  () => missing(input.path, target.absolute),
+                ),
+              )
               // After a successful read, discover nearby AGENTS.md walking up to the Location
               // root exclusive and inject them as durable synthetic instructions. For a
               // directory listing the walk starts at the directory itself (so its own AGENTS.md
@@ -95,7 +92,7 @@ export const Plugin = {
                 // supplied by core initial instructions) is dropped by the dirname filter.
                 const discovered = yield* fs.up({
                   targets: [FILENAME],
-                  start: type === "directory" ? resolved : dirname(resolved),
+                  start: content.type === "list-page" ? resolved : dirname(resolved),
                   stop: root,
                 })
                 const candidates = (yield* Effect.forEach(discovered, fs.resolve)).filter(

packages/core/src/tool/plugin/shell.ts

@@ -5,8 +5,8 @@ import { ToolFailure } from "@opencode-ai/ai"
 import type { Content } from "@opencode-ai/schema/tool"
 import type { Context as PluginContext } from "@opencode-ai/plugin/effect/plugin"
 import { Deferred, Effect, Schema, Scope } from "effect"
-import { FSUtil } from "@opencode-ai/util/fs-util"
 import { Config } from "../../config"
+import { Environment } from "../../environment"
 import { LocationMutation } from "../../location-mutation"
 import { Permission } from "../../permission"
 import { PluginRuntime } from "../../plugin/runtime"
@@ -83,7 +83,7 @@ export const Plugin = {
   effect: Effect.fn("ShellTool.Plugin")(function* (ctx: PluginContext) {
     const runtime = yield* PluginRuntime.Service
     const scope = yield* Scope.Scope
-    const fsUtil = yield* FSUtil.Service
+    const environment = yield* Environment.Service
     const mutation = yield* LocationMutation.Service
     const shell = yield* Shell.Service
     const permission = yield* Permission.Service
@@ -179,14 +179,12 @@ export const Plugin = {
                         agent: context.agent,
                         source,
                       })
-                    const workdir = yield* fsUtil
-                      .stat(target.absolute)
-                      .pipe(
-                        Effect.catchReason("PlatformError", "NotFound", () =>
-                          Effect.fail(new Error(`Working directory does not exist: ${target.absolute}`)),
-                        ),
-                      )
-                    if (workdir.type !== "Directory")
+                    const workdir = yield* Environment.typeFollowing(environment.files, target.absolute).pipe(
+                      Effect.catchTag("Environment.NotFound", () =>
+                        Effect.fail(new Error(`Working directory does not exist: ${target.absolute}`)),
+                      ),
+                    )
+                    if (workdir !== "directory")
                       return yield* Effect.fail(new Error(`Working directory is not a directory: ${target.absolute}`))
                   }),
               )

packages/core/src/tool/plugin/write.ts

@@ -10,7 +10,7 @@ import type { Context as PluginContext } from "@opencode-ai/plugin/effect/plugin
 import { ToolFailure } from "@opencode-ai/ai"
 import { Effect, Schema } from "effect"
 import { Bom } from "@opencode-ai/util/bom"
-import { FSUtil } from "@opencode-ai/util/fs-util"
+import { Environment } from "../../environment"
 import { FileMutation } from "../../file-mutation"
 import { Formatter } from "../../formatter"
 import { LocationMutation } from "../../location-mutation"
@@ -47,9 +47,9 @@ export const Plugin = {
   id: "opencode.tool.write",
   effect: Effect.fn("WriteTool.Plugin")(function* (ctx: PluginContext) {
     const mutation = yield* LocationMutation.Service
-    const files = yield* FileMutation.Service
+    const fileMutation = yield* FileMutation.Service
+    const environment = yield* Environment.Service
     const formatter = yield* Formatter.Service
-    const fs = yield* FSUtil.Service
     const permission = yield* Permission.Service
 
     yield* ctx.tool
@@ -77,8 +77,8 @@ export const Plugin = {
                   agent: context.agent,
                   source,
                 })
-              const current = yield* Bom.readFile(fs, target.absolute).pipe(
-                Effect.catchReason("PlatformError", "NotFound", () => Effect.succeed(undefined)),
+              const current = yield* FileMutation.readText(environment.files, target.absolute).pipe(
+                Effect.catchTag("Environment.NotFound", () => Effect.succeed(undefined)),
               )
               const next = Bom.split(input.content)
               const preview = fileDiff(target.resource, current?.text ?? "", next.text, current ? "modified" : "added")
@@ -91,9 +91,11 @@ export const Plugin = {
                 agent: context.agent,
                 source,
               })
-              const result = yield* files.writeTextPreservingBom({ target, content: input.content })
-              const bom = (yield* Bom.readFile(fs, target.absolute)).bom
-              if (yield* formatter.file(target.absolute)) yield* Bom.syncFile(fs, target.absolute, bom)
+              const result = yield* fileMutation.writeTextPreservingBom({ target, content: input.content })
+              const bom = (yield* FileMutation.readText(environment.files, target.absolute)).bom
+              if (yield* formatter.file(target.absolute)) {
+                yield* FileMutation.syncTextBom(environment.files, target.absolute, bom)
+              }
               return result
             }).pipe(
               Effect.map((output) => ({ output, content: toModelOutput(output) })),

packages/core/src/tool/read-filesystem.ts

@@ -2,17 +2,22 @@ export * as ReadToolFileSystem from "./read-filesystem"
 
 import path from "path"
 import { pathToFileURL } from "url"
-import { Context, Effect, Layer, Option, Schema } from "effect"
-import { FileSystem } from "../filesystem"
-import { FSUtil } from "@opencode-ai/util/fs-util"
 import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
+import { Context, Effect, Layer, Schema } from "effect"
+import { lookup } from "mime-types"
+import { Environment } from "../environment"
+import type { Files } from "../environment"
+import { FileSystem } from "../filesystem"
+import { Mime } from "../mime"
 import { AbsolutePath, NonNegativeInt, PositiveInt, RelativePath } from "../schema"
 
 export const MAX_READ_LINES = 2_000
 export const MAX_READ_BYTES = 50 * 1024
 export const MAX_MEDIA_INGEST_BYTES = 20 * 1024 * 1024
+const FIRST_CHUNK = 256 * 1024
 const MAX_LINE_LENGTH = 2_000
 const MAX_LINE_SUFFIX = `... (line truncated to ${MAX_LINE_LENGTH} chars)`
+const MEDIA_MIMES = new Set(["image/png", "image/jpeg", "image/gif", "image/webp", "application/pdf"])
 
 export class BinaryFileError extends Schema.TaggedErrorClass<BinaryFileError>()("ReadTool.BinaryFileError", {
   resource: Schema.String,
@@ -52,8 +57,13 @@ export class PathKindError extends Schema.TaggedErrorClass<PathKindError>()("Rea
   }
 }
 
-export type InspectError = FSUtil.Error | PathKindError
-export type ReadError = FSUtil.Error | BinaryFileError | MediaIngestLimitError | OffsetOutOfRangeError | PathKindError
+export type ReadError =
+  | Environment.NotFound
+  | Environment.Failed
+  | BinaryFileError
+  | MediaIngestLimitError
+  | OffsetOutOfRangeError
+  | PathKindError
 
 export const PageInput = Schema.Struct({
   offset: Schema.optionalKey(NonNegativeInt),
@@ -90,202 +100,113 @@ export class ListPage extends Schema.Class<ListPage>("ReadTool.ListPage")({
 }) {}
 
 export interface Interface {
-  readonly inspect: (path: AbsolutePath) => Effect.Effect<"file" | "directory", InspectError>
   readonly read: (
     path: AbsolutePath,
     resource: string,
     page?: PageInput,
-  ) => Effect.Effect<FileContent | TextPage, ReadError>
-  readonly list: (path: AbsolutePath, page?: PageInput) => Effect.Effect<ListPage, FSUtil.Error>
+  ) => Effect.Effect<FileContent | TextPage | ListPage, ReadError>
 }
 
 export class Service extends Context.Service<Service, Interface>()("@opencode/ReadToolFileSystem") {}
 
-const startsWith = (bytes: Uint8Array, prefix: number[]) => prefix.every((value, index) => bytes[index] === value)
-const mediaMime = (bytes: Uint8Array) => {
-  if (startsWith(bytes, [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a])) return "image/png"
-  if (startsWith(bytes, [0xff, 0xd8, 0xff])) return "image/jpeg"
-  if (startsWith(bytes, [0x47, 0x49, 0x46, 0x38])) return "image/gif"
-  if (startsWith(bytes, [0x52, 0x49, 0x46, 0x46]) && startsWith(bytes.subarray(8), [0x57, 0x45, 0x42, 0x50]))
-    return "image/webp"
-  if (startsWith(bytes, [0x25, 0x50, 0x44, 0x46, 0x2d])) return "application/pdf"
-}
-const binary = (bytes: Uint8Array) => {
-  if (bytes.length === 0) return false
-  let nonPrintable = 0
-  for (const byte of bytes) {
-    if (byte === 0) return true
-    if (byte < 9 || (byte > 13 && byte < 32)) nonPrintable++
-  }
-  return nonPrintable / bytes.length > 0.3
-}
-const decodeUtf8 = (decoder: TextDecoder, bytes?: Uint8Array) => decoder.decode(bytes, { stream: bytes !== undefined })
-const decodeChunk = (resource: string, decoder: TextDecoder, bytes: Uint8Array) =>
-  bytes.includes(0) ? Effect.fail(new BinaryFileError({ resource })) : Effect.succeed(decodeUtf8(decoder, bytes))
-
-export const inspect = Effect.fn("ReadTool.inspect")(function* (fs: FSUtil.Interface, input: string) {
-  const info = yield* fs.stat(input)
-  const type = info.type === "File" ? "file" : info.type === "Directory" ? "directory" : undefined
-  if (!type) return yield* Effect.fail(new PathKindError({ resource: input, expected: "a file or directory" }))
-  return type
-})
+const mimeType = (value: string) => lookup(value) || "application/octet-stream"
 
 export const read = Effect.fn("ReadTool.read")(function* (
-  fs: FSUtil.Interface,
-  input: string,
+  files: Files,
+  input: AbsolutePath,
   resource: string,
   page: PageInput = {},
 ) {
-  const real = yield* fs.realPath(input)
-  return yield* Effect.scoped(
-    Effect.gen(function* () {
-      const file = yield* fs.open(real, { flag: "r" })
-      const info = yield* file.stat
-      if (info.type !== "File") return yield* Effect.fail(new PathKindError({ resource, expected: "a file" }))
-      const first = Option.getOrElse(
-        yield* file.readAlloc(Math.min(64 * 1024, Number(info.size) || 4 * 1024)),
-        () => new Uint8Array(),
+  const first = yield* files.read(input, { offset: 0, length: FIRST_CHUNK }).pipe(
+    Effect.catchTag("Environment.WrongKind", (error) => {
+      if (error.actual !== "directory")
+        return Effect.fail(new PathKindError({ resource, expected: "a file or directory" }))
+      return files.list(input).pipe(
+        Effect.map((entries) => list(entries, page)),
+        Effect.catchTag("Environment.WrongKind", () =>
+          Effect.fail(new PathKindError({ resource, expected: "a file or directory" })),
+        ),
       )
-      const mime = mediaMime(first)
-      if (mime) {
-        if (info.size > MAX_MEDIA_INGEST_BYTES)
-          return yield* Effect.fail(new MediaIngestLimitError({ resource, maximumBytes: MAX_MEDIA_INGEST_BYTES }))
-        const chunks = [first]
-        let total = first.length
-        while (total <= MAX_MEDIA_INGEST_BYTES) {
-          const chunk = yield* file.readAlloc(Math.min(64 * 1024, MAX_MEDIA_INGEST_BYTES + 1 - total))
-          if (Option.isNone(chunk)) break
-          chunks.push(chunk.value)
-          total += chunk.value.length
-        }
-        if (total > MAX_MEDIA_INGEST_BYTES)
-          return yield* Effect.fail(new MediaIngestLimitError({ resource, maximumBytes: MAX_MEDIA_INGEST_BYTES }))
-        return {
-          type: "file" as const,
-          uri: pathToFileURL(real).href,
-          name: path.basename(real),
-          content: Buffer.concat(
-            chunks.map((chunk) => Buffer.from(chunk)),
-            total,
-          ).toString("base64"),
-          encoding: "base64" as const,
-          mime,
-        }
-      }
-      const paged = info.size > MAX_READ_BYTES || page.offset !== undefined || page.limit !== undefined
-      if (!paged) {
-        if (binary(first)) return yield* Effect.fail(new BinaryFileError({ resource }))
-        const decoder = new TextDecoder()
-        const text = [decodeUtf8(decoder, first)]
-        while (true) {
-          const chunk = yield* file.readAlloc(64 * 1024)
-          if (Option.isNone(chunk)) break
-          text.push(yield* decodeChunk(resource, decoder, chunk.value))
-        }
-        text.push(decodeUtf8(decoder))
-        return {
-          type: "file" as const,
-          uri: pathToFileURL(real).href,
-          name: path.basename(real),
-          content: text.join(""),
-          encoding: "utf8" as const,
-          mime: FSUtil.mimeType(real),
-        }
-      }
-      const offset = page.offset || 1
-      const limit = Math.min(page.limit || MAX_READ_LINES, MAX_READ_LINES)
-      const lines: string[] = []
-      const decoder = new TextDecoder()
-      let pending = ""
-      let discard = false
-      let line = 1
-      let bytes = 0
-      let next: number | undefined
-      const append = (input: string) => {
-        if (line < offset) {
-          line++
-          return true
-        }
-        if (lines.length >= limit || bytes >= MAX_READ_BYTES) {
-          next = line
-          return false
-        }
-        const text = input.length > MAX_LINE_LENGTH ? input.slice(0, MAX_LINE_LENGTH) + MAX_LINE_SUFFIX : input
-        const size = Buffer.byteLength(text, "utf-8") + (lines.length > 0 ? 1 : 0)
-        if (bytes + size > MAX_READ_BYTES) {
-          next = line
-          return false
-        }
-        lines.push(text)
-        bytes += size
-        line++
-        return true
-      }
-      const consume = (input: string) => {
-        let text = input
-        while (true) {
-          const index = text.indexOf("\n")
-          if (index === -1) {
-            if (!discard) {
-              pending += text
-              if (pending.length > MAX_LINE_LENGTH) {
-                pending = pending.slice(0, MAX_LINE_LENGTH + 1)
-                discard = true
-              }
-            }
-            break
-          }
-          const current = pending + (discard ? "" : text.slice(0, index))
-          pending = ""
-          discard = false
-          text = text.slice(index + 1)
-          if (!append(current.endsWith("\r") ? current.slice(0, -1) : current)) return false
-        }
-        return true
-      }
-      const consumeChunk = Effect.fnUntraced(function* (chunk: Uint8Array) {
-        let start = 0
-        while (start < chunk.length) {
-          if (lines.length >= limit || bytes >= MAX_READ_BYTES) {
-            next = line
-            return false
-          }
-          const newline = chunk.indexOf(10, start)
-          const end = newline === -1 ? chunk.length : newline + 1
-          const segment = chunk.subarray(start, end)
-          if (binary(segment)) return yield* Effect.fail(new BinaryFileError({ resource }))
-          if (!consume(decodeUtf8(decoder, segment))) return false
-          start = end
-        }
-        return true
-      })
-      let done = !(yield* consumeChunk(first))
-      while (!done) {
-        const chunk = yield* file.readAlloc(64 * 1024)
-        if (Option.isNone(chunk)) break
-        done = !(yield* consumeChunk(chunk.value))
-      }
-      if (!done) {
-        const tail = decodeUtf8(decoder)
-        if (!discard) pending += tail
-        if (pending) append(pending.endsWith("\r") ? pending.slice(0, -1) : pending)
-      }
-      if (lines.length === 0 && offset !== 1) return yield* Effect.fail(new OffsetOutOfRangeError({ offset }))
-      return new TextPage({
-        type: "text-page",
-        content: lines.join("\n"),
-        mime: FSUtil.mimeType(real),
-        offset,
-        truncated: next !== undefined,
-        ...(next === undefined ? {} : { next }),
-      })
     }),
   )
+  if (first instanceof ListPage) return first
+
+  const media = Mime.detect(first.bytes)
+  if (MEDIA_MIMES.has(media)) {
+    if (first.info.size > MAX_MEDIA_INGEST_BYTES)
+      return yield* new MediaIngestLimitError({ resource, maximumBytes: MAX_MEDIA_INGEST_BYTES })
+    const whole = yield* readFile(files, input, resource)
+    return {
+      type: "file" as const,
+      uri: pathToFileURL(input).href,
+      name: path.basename(input),
+      content: Buffer.from(whole.bytes).toString("base64"),
+      encoding: "base64" as const,
+      mime: media,
+    }
+  }
+
+  const paged = first.info.size > MAX_READ_BYTES || page.offset !== undefined || page.limit !== undefined
+  if (!paged) {
+    if (first.bytes.includes(0)) return yield* new BinaryFileError({ resource })
+    return {
+      type: "file" as const,
+      uri: pathToFileURL(input).href,
+      name: path.basename(input),
+      content: new TextDecoder().decode(first.bytes),
+      encoding: "utf8" as const,
+      mime: mimeType(input),
+    }
+  }
+
+  const chunks = [first.bytes]
+  while (true) {
+    const bytes = Buffer.concat(chunks)
+    const eof = bytes.length >= first.info.size
+    const result = textPage(bytes, eof, page)
+    if (result !== undefined) return yield* makeTextPage(bytes, input, resource, result)
+    const next = yield* readFile(files, input, resource, { offset: bytes.length, length: FIRST_CHUNK })
+    if (next.bytes.length === 0) {
+      const result = textPage(bytes, true, page)
+      if (result === undefined) return yield* Effect.die("Read page did not settle at EOF")
+      return yield* makeTextPage(bytes, input, resource, result)
+    }
+    chunks.push(next.bytes)
+  }
 })
 
-export const list = Effect.fn("ReadTool.list")(function* (fs: FSUtil.Interface, input: string, page: PageInput = {}) {
-  const real = yield* fs.realPath(input)
-  const items = yield* fs.readDirectoryEntries(real)
+const readFile = (
+  files: Files,
+  input: AbsolutePath,
+  resource: string,
+  range?: { readonly offset: number; readonly length: number },
+) =>
+  files
+    .read(input, range)
+    .pipe(
+      Effect.catchTag("Environment.WrongKind", () => Effect.fail(new PathKindError({ resource, expected: "a file" }))),
+    )
+
+const makeTextPage = Effect.fnUntraced(function* (
+  bytes: Uint8Array,
+  input: AbsolutePath,
+  resource: string,
+  result: NonNullable<ReturnType<typeof textPage>>,
+) {
+  if (bytes.subarray(0, result.consumed).includes(0)) return yield* new BinaryFileError({ resource })
+  if (result.entries.length === 0 && result.offset !== 1)
+    return yield* new OffsetOutOfRangeError({ offset: result.offset })
+  return new TextPage({
+    type: "text-page",
+    content: result.entries.join("\n"),
+    mime: mimeType(input),
+    offset: result.offset,
+    truncated: result.next !== undefined,
+    ...(result.next === undefined ? {} : { next: result.next }),
+  })
+})
+
+const list = (items: ReadonlyArray<Environment.DirEntry>, page: PageInput) => {
   const offset = page.offset || 1
   const limit = Math.min(page.limit || MAX_READ_LINES, MAX_READ_LINES)
   const visible = items
@@ -316,18 +237,58 @@ export const list = Effect.fn("ReadTool.list")(function* (fs: FSUtil.Interface,
     truncated,
     ...(truncated ? { next: offset + selected.length } : {}),
   })
-})
+}
+
+const textPage = (bytes: Uint8Array, eof: boolean, page: PageInput) => {
+  const offset = page.offset || 1
+  const limit = Math.min(page.limit || MAX_READ_LINES, MAX_READ_LINES)
+  const decoded = new TextDecoder().decode(bytes)
+  const split = decoded.split("\n")
+  const complete = eof ? (split.at(-1) === "" ? split.slice(0, -1) : split) : split.slice(0, -1)
+  const available = complete.map((line) => (line.endsWith("\r") ? line.slice(0, -1) : line))
+
+  const entries: string[] = []
+  let size = 0
+  let next: number | undefined
+  for (const [index, value] of available.slice(offset - 1).entries()) {
+    const line = offset + index
+    if (entries.length >= limit || size >= MAX_READ_BYTES) {
+      next = line
+      break
+    }
+    const text = value.length > MAX_LINE_LENGTH ? value.slice(0, MAX_LINE_LENGTH) + MAX_LINE_SUFFIX : value
+    const lineSize = Buffer.byteLength(text, "utf-8") + (entries.length > 0 ? 1 : 0)
+    if (size + lineSize > MAX_READ_BYTES) {
+      next = line
+      break
+    }
+    entries.push(text)
+    size += lineSize
+  }
+  if (next === undefined && entries.length >= limit && (!eof || offset - 1 + entries.length < available.length))
+    next = offset + entries.length
+  if (!eof && next === undefined) return
+
+  const consumedLines = next === undefined ? available.length : next - 1
+  const consumed = consumedLines === 0 ? 0 : (nthNewline(bytes, consumedLines) ?? bytes.length)
+  return { entries, offset, next, consumed }
+}
+
+const nthNewline = (bytes: Uint8Array, count: number) => {
+  let found = 0
+  for (const [index, byte] of bytes.entries()) {
+    if (byte !== 10) continue
+    found++
+    if (found === count) return index + 1
+  }
+}
 
 const layer = Layer.effect(
   Service,
   Effect.gen(function* () {
-    const fs = yield* FSUtil.Service
-    return Service.of({
-      inspect: (path) => inspect(fs, path),
-      read: (path, resource, page) => read(fs, path, resource, page),
-      list: (path, page) => list(fs, path, page),
-    })
+    const environment = yield* Environment.Service
+    return Service.of({ read: (path, resource, page) => read(environment.files, path, resource, page) })
   }),
 )
 
-export const node = makeLocationNode({ service: Service, layer, deps: [FSUtil.node] })
+export const node = makeLocationNode({ service: Service, layer, deps: [Environment.node] })

packages/core/test/config/provider.test.ts

@@ -50,6 +50,33 @@ function withEnv<A, E, R>(vars: Record<string, string | undefined>, effect: () =
 const decode = Schema.decodeUnknownSync(Info)
 
 describe("ConfigProviderPlugin.Plugin", () => {
+  it.effect("adds key auth for custom providers without env credentials", () =>
+    Effect.gen(function* () {
+      const integrations = yield* Integration.Service
+      const entries = [
+        new Document({
+          type: "document",
+          info: decode({
+            providers: {
+              litellm: {
+                package: "aisdk:@ai-sdk/openai-compatible",
+                models: { chat: {} },
+              },
+            },
+          }),
+        }),
+      ]
+
+      yield* addPlugin(entries)
+
+      expect(yield* integrations.get(Integration.ID.make("litellm"))).toMatchObject({
+        id: "litellm",
+        name: "litellm",
+        methods: [{ type: "key", label: "Manually enter API Key" }],
+      })
+    }),
+  )
+
   it.effect("defaults custom models to agent capabilities", () =>
     Effect.gen(function* () {
       const catalog = yield* Catalog.Service

packages/core/test/environment.test.ts

@@ -1,11 +1,39 @@
 import fs from "node:fs/promises"
+import { describe, expect } from "bun:test"
 import { Effect } from "effect"
 import { ChildProcessSpawner } from "effect/unstable/process"
 import { CrossSpawnSpawner } from "@opencode-ai/util/cross-spawn-spawner"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
-import { execDefaults, Failed, makeFiles, makeMemoryDriver } from "../src/environment/index"
+import {
+  execDefaults,
+  Failed,
+  makeFiles,
+  makeLocalDriver,
+  makeMemoryDriver,
+  NotFound,
+  typeFollowing,
+} from "../src/environment/index"
 import { tmpdir } from "./fixture/tmpdir"
 import { environmentConformance } from "./lib/environment-conformance"
+import { it } from "./lib/effect"
+
+describe("typeFollowing", () => {
+  it.effect("follows symlinks without changing stat semantics", () =>
+    Effect.gen(function* () {
+      const driver = makeMemoryDriver()
+      const files = makeFiles(driver)
+      yield* files.mkdir("/directory")
+      yield* files.write("/file", new Uint8Array())
+      yield* driver.symlink("/directory", "/directory-link")
+      yield* driver.symlink("/file", "/file-link")
+      yield* driver.symlink("/missing", "/dangling-link")
+
+      expect(yield* typeFollowing(files, "/directory-link")).toBe("directory")
+      expect(yield* typeFollowing(files, "/file-link")).toBe("file")
+      expect(yield* typeFollowing(files, "/dangling-link").pipe(Effect.flip)).toBeInstanceOf(NotFound)
+    }),
+  )
+})
 
 environmentConformance("memory environment", () =>
   Effect.sync(() => {
@@ -18,6 +46,27 @@ environmentConformance("memory environment", () =>
   }),
 )
 
+environmentConformance("local environment", () =>
+  Effect.gen(function* () {
+    const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
+    const tmp = yield* Effect.promise(() => tmpdir("opencode-local-environment-"))
+    return {
+      files: makeFiles(makeLocalDriver(spawner)),
+      root: tmp.path,
+      ...(process.platform === "win32"
+        ? {}
+        : {
+            symlink: (target: string, link: string) =>
+              Effect.tryPromise({
+                try: () => fs.symlink(target, link),
+                catch: (cause) => new Failed({ path: link, cause }),
+              }),
+          }),
+      dispose: Effect.promise(() => tmp[Symbol.asyncDispose]()),
+    }
+  }).pipe(Effect.provide(LayerNode.compile(CrossSpawnSpawner.node))),
+)
+
 environmentConformance(
   "GNU exec environment",
   () =>

packages/core/test/file-mutation.test.ts

@@ -5,7 +5,7 @@ import { Deferred, Effect, Fiber, Layer } from "effect"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
 import { FileMutation } from "@opencode-ai/core/file-mutation"
-import { FSUtil } from "@opencode-ai/util/fs-util"
+import { Environment } from "@opencode-ai/core/environment"
 import { Location } from "@opencode-ai/core/location"
 import { LocationMutation } from "@opencode-ai/core/location-mutation"
 import { AbsolutePath } from "@opencode-ai/core/schema"
@@ -13,7 +13,7 @@ import { location } from "./fixture/location"
 import { tmpdir } from "./fixture/tmpdir"
 import { it } from "./lib/effect"
 
-function provide(directory: string, filesystemLayer = LayerNode.compile(FSUtil.node)) {
+function provide(directory: string, environmentLayer = LayerNode.compile(Environment.node)) {
   const activeLocation = Layer.succeed(
     Location.Service,
     Location.Service.of(location({ directory: AbsolutePath.make(directory) })),
@@ -21,7 +21,7 @@ function provide(directory: string, filesystemLayer = LayerNode.compile(FSUtil.n
   return Effect.provide(
     AppNodeBuilder.build(LayerNode.group([LocationMutation.node, FileMutation.node]), [
       [Location.node, activeLocation],
-      [FSUtil.node, filesystemLayer],
+      [Environment.node, environmentLayer],
     ]),
   )
 }
@@ -152,6 +152,57 @@ describe("FileMutation", () => {
     ),
   )
 
+  it.live("shares transaction locks across Location service instances", () =>
+    withTmp((directory) =>
+      Effect.gen(function* () {
+        const firstStarted = yield* Deferred.make<void>()
+        const releaseFirst = yield* Deferred.make<void>()
+        const secondStarted = yield* Deferred.make<void>()
+        const target = path.join(directory, "shared.txt")
+        const first = yield* Effect.gen(function* () {
+          const files = yield* FileMutation.Service
+          yield* files.withLock([target])(
+            Deferred.succeed(firstStarted, undefined).pipe(Effect.andThen(Deferred.await(releaseFirst))),
+          )
+        }).pipe(provide(directory), Effect.forkChild)
+        yield* Deferred.await(firstStarted)
+        const second = yield* Effect.gen(function* () {
+          const files = yield* FileMutation.Service
+          yield* files.withLock([target])(Deferred.succeed(secondStarted, undefined))
+        }).pipe(provide(directory), Effect.forkChild)
+        yield* Effect.yieldNow
+        expect(yield* Deferred.isDone(secondStarted)).toBe(false)
+
+        yield* Deferred.succeed(releaseFirst, undefined)
+        yield* Deferred.await(secondStarted)
+        yield* Fiber.join(first)
+        yield* Fiber.join(second)
+      }),
+    ),
+  )
+
+  it.live("allows transaction locks for distinct resolved paths to proceed independently", () =>
+    withTmp((directory) =>
+      Effect.gen(function* () {
+        const firstStarted = yield* Deferred.make<void>()
+        const releaseFirst = yield* Deferred.make<void>()
+        const secondFinished = yield* Deferred.make<void>()
+        const files = yield* FileMutation.Service
+        const first = yield* files
+          .withLock([path.join(directory, "first.txt")])(
+            Deferred.succeed(firstStarted, undefined).pipe(Effect.andThen(Deferred.await(releaseFirst))),
+          )
+          .pipe(Effect.forkChild)
+        yield* Deferred.await(firstStarted)
+        yield* files.withLock([path.join(directory, "second.txt")])(Deferred.succeed(secondFinished, undefined))
+        expect(yield* Deferred.isDone(secondFinished)).toBe(true)
+
+        yield* Deferred.succeed(releaseFirst, undefined)
+        yield* Fiber.join(first)
+      }).pipe(provide(directory)),
+    ),
+  )
+
   it.live("allows distinct absolute targets to proceed independently", () =>
     withTmp((directory) =>
       Effect.gen(function* () {
@@ -191,16 +242,16 @@ describe("FileMutation", () => {
 
 function instrumentWrites(run: <E>(write: Effect.Effect<void, E>, target: string) => Effect.Effect<void, E>) {
   return Layer.effect(
-    FSUtil.Service,
+    Environment.Service,
     Effect.gen(function* () {
-      const filesystem = yield* FSUtil.Service
-      return FSUtil.Service.of({
-        ...filesystem,
-        writeWithDirs: (target, content, mode) => run(filesystem.writeWithDirs(target, content, mode), target),
-        writeFile: (target, content, options) => run(filesystem.writeFile(target, content, options), target),
-        writeFileString: (target, content, options) =>
-          run(filesystem.writeFileString(target, content, options), target),
+      const environment = yield* Environment.Service
+      return Environment.Service.of({
+        ...environment,
+        files: {
+          ...environment.files,
+          write: (target, content) => run(environment.files.write(target, content), target),
+        },
       })
     }),
-  ).pipe(Layer.provide(LayerNode.compile(FSUtil.node)))
+  ).pipe(Layer.provide(LayerNode.compile(Environment.node)))
 }

packages/core/test/filesystem/watcher.test.ts

@@ -17,9 +17,8 @@ import { location } from "../fixture/location"
 import { tmpdir } from "../fixture/tmpdir"
 import { testEffect } from "../lib/effect"
 
-const describeWatcher = Watcher.hasNativeBinding() && !process.env.CI ? describe : describe.skip
-
 type WatcherEvent = { file: string; event: "add" | "change" | "unlink" }
+const describeNative = process.env.CI ? describe.skip : describe
 
 const it = testEffect(AppNodeBuilder.build(LayerNode.group([FSUtil.node, Bus.node])))
 
@@ -75,10 +74,9 @@ describe("Watcher lifecycle", () => {
       const interrupted = yield* Deferred.make<void>()
       yield* Effect.gen(function* () {
         const watcher = yield* Watcher.Service
-        const consumer = yield* watcher.subscribe({ path: "/pending", type: "directory" }).pipe(
-          Effect.flatMap(Stream.runDrain),
-          Effect.forkScoped({ startImmediately: true }),
-        )
+        const consumer = yield* watcher
+          .subscribe({ path: "/pending", type: "directory" })
+          .pipe(Effect.flatMap(Stream.runDrain), Effect.forkScoped({ startImmediately: true }))
         yield* Deferred.await(started)
         yield* Fiber.interrupt(consumer)
         expect(yield* Deferred.isDone(interrupted)).toBe(true)
@@ -99,10 +97,9 @@ describe("Watcher lifecycle", () => {
     return Effect.gen(function* () {
       const watcher = yield* Watcher.Service
       const consume = () =>
-        watcher.subscribe({ path: "/shared", type: "directory" }).pipe(
-          Effect.flatMap(Stream.runDrain),
-          Effect.forkScoped({ startImmediately: true }),
-        )
+        watcher
+          .subscribe({ path: "/shared", type: "directory" })
+          .pipe(Effect.flatMap(Stream.runDrain), Effect.forkScoped({ startImmediately: true }))
       const first = yield* consume()
       const second = yield* consume()
       yield* Effect.yieldNow
@@ -138,22 +135,26 @@ describe("Watcher lifecycle", () => {
   })
 })
 
-function provide(directory: string, vcs?: Location.Interface["vcs"]) {
+function provide(directory: string, vcs?: Location.Interface["vcs"], watcher?: Layer.Layer<Watcher.Service>) {
   const locationLayer = Layer.succeed(
     Location.Service,
     Location.Service.of(location({ directory: AbsolutePath.make(directory) }, { vcs })),
   )
-  return Effect.provide(
-    AppNodeBuilder.build(LocationWatcher.node, [
-      [Config.node, configLayer],
-      [Location.node, locationLayer],
-    ]),
-  )
+  const built = AppNodeBuilder.build(LocationWatcher.node, [
+    [Config.node, configLayer],
+    [Location.node, locationLayer],
+    ...(watcher ? ([[Watcher.node, watcher]] as const) : []),
+  ])
+  return Effect.provide(built)
 }
 
 function withTmp<A, E, R>(
   f: (directory: string, vcs?: Location.Interface["vcs"]) => Effect.Effect<A, E, R>,
-  options?: { vcs?: "git" | "hg"; init?: (directory: string) => Promise<void> },
+  options?: {
+    vcs?: "git" | "hg"
+    init?: (directory: string) => Promise<void>
+    watcher?: Layer.Layer<Watcher.Service>
+  },
 ) {
   return Effect.acquireRelease(
     Effect.promise(async () => {
@@ -173,9 +174,57 @@ function withTmp<A, E, R>(
       return { tmp, vcs: { type: "git" as const, store: AbsolutePath.make(path.join(tmp.path, ".git")) } }
     }),
     ({ tmp }) => Effect.promise(() => tmp[Symbol.asyncDispose]()),
-  ).pipe(Effect.flatMap(({ tmp, vcs }) => f(tmp.path, vcs).pipe(provide(tmp.path, vcs))))
+  ).pipe(Effect.flatMap(({ tmp, vcs }) => f(tmp.path, vcs).pipe(provide(tmp.path, vcs, options?.watcher))))
 }
 
+describe("LocationWatcher subscriptions", () => {
+  it.live("watches only exact Git branch metadata", () => {
+    const subscriptions: Watcher.WatchInput[] = []
+    const watcher = Layer.succeed(
+      Watcher.Service,
+      Watcher.Service.of({
+        subscribe: (input) => Effect.sync(() => subscriptions.push(input)).pipe(Effect.as(Stream.empty)),
+      }),
+    )
+    return withTmp(
+      (directory) =>
+        Effect.gen(function* () {
+          yield* LocationWatcher.Service
+          yield* Effect.sync(() => subscriptions.length).pipe(
+            Effect.filterOrFail((count) => count > 0),
+            Effect.retry(Schedule.spaced("10 millis")),
+          )
+          yield* Effect.sleep("10 millis")
+          expect(subscriptions).toEqual([{ path: path.join(directory, ".git", "HEAD"), type: "file" }])
+        }),
+      { vcs: "git", watcher },
+    )
+  })
+
+  it.live("watches only exact Hg branch metadata", () => {
+    const subscriptions: Watcher.WatchInput[] = []
+    const watcher = Layer.succeed(
+      Watcher.Service,
+      Watcher.Service.of({
+        subscribe: (input) => Effect.sync(() => subscriptions.push(input)).pipe(Effect.as(Stream.empty)),
+      }),
+    )
+    return withTmp(
+      (directory) =>
+        Effect.gen(function* () {
+          yield* LocationWatcher.Service
+          yield* Effect.sync(() => subscriptions.length).pipe(
+            Effect.filterOrFail((count) => count > 0),
+            Effect.retry(Schedule.spaced("10 millis")),
+          )
+          yield* Effect.sleep("10 millis")
+          expect(subscriptions).toEqual([{ path: path.join(directory, ".hg", "branch"), type: "file" }])
+        }),
+      { vcs: "hg", watcher },
+    )
+  })
+})
+
 function wait(check: (event: WatcherEvent) => boolean) {
   return Effect.gen(function* () {
     const bus = yield* Bus.Service
@@ -226,31 +275,18 @@ function eventuallyUpdate<E>(check: (event: WatcherEvent) => boolean, trigger: (
   )
 }
 
-function noUpdate<E>(check: (event: WatcherEvent) => boolean, trigger: Effect.Effect<void, E>, timeout = 500) {
-  return Effect.acquireUseRelease(
-    wait(check),
-    ({ deferred }) =>
-      trigger.pipe(
-        Effect.andThen(Deferred.await(deferred)),
-        Effect.timeoutOption(`${timeout} millis`),
-        Effect.tap((result) => Effect.sync(() => expect(result).toEqual(Option.none()))),
-      ),
-    ({ fiber }) => Fiber.interrupt(fiber),
-  )
-}
-
-function ready(directory: string) {
-  const file = path.join(directory, `.watcher-${Math.random().toString(36).slice(2)}`)
+function ready(file: string, eventFile = file) {
   return Effect.gen(function* () {
     const fs = yield* FSUtil.Service
+    const content = (yield* fs.readFileStringSafe(file)) ?? `ready-${Math.random()}`
     yield* eventuallyUpdate(
-      (event) => event.file === file,
-      () => fs.writeFileString(file, `ready-${Math.random()}`),
-    ).pipe(Effect.ensuring(fs.remove(file, { force: true }).pipe(Effect.ignore)), Effect.asVoid)
+      (event) => event.file === eventFile,
+      () => fs.writeFileString(file, content),
+    ).pipe(Effect.asVoid)
   })
 }
 
-describeWatcher("LocationWatcher", () => {
+describeNative("LocationWatcher", () => {
   it.live("limits file watches to the exact target", () =>
     withTmp((directory) =>
       Effect.gen(function* () {
@@ -276,94 +312,25 @@ describeWatcher("LocationWatcher", () => {
     ),
   )
 
-  it.live("publishes root create, update, and delete events", () =>
-    withTmp(
-      (directory) =>
-        Effect.gen(function* () {
-          const fs = yield* FSUtil.Service
-          const file = path.join(directory, "watch.txt")
-          yield* ready(directory)
-          for (const item of [
-            { event: "add" as const, trigger: fs.writeFileString(file, "a") },
-            { event: "change" as const, trigger: fs.writeFileString(file, "b") },
-            { event: "unlink" as const, trigger: fs.remove(file) },
-          ]) {
-            expect(
-              yield* nextUpdate((event) => event.file === file && event.event === item.event, item.trigger),
-            ).toEqual({
-              file,
-              event: item.event,
-            })
-          }
-        }),
-      { vcs: "git" },
-    ),
-  )
-
-  it.live("skips non-git roots", () =>
+  it.live("detects creation of a missing directory target", () =>
     withTmp((directory) =>
       Effect.gen(function* () {
         const fs = yield* FSUtil.Service
-        const file = path.join(directory, "plain.txt")
-        yield* noUpdate((event) => event.file === file, fs.writeFileString(file, "plain"))
-      }),
-    ),
-  )
+        const watcher = yield* Watcher.Service
+        const target = path.join(directory, "generated")
+        const updates = yield* watcher.subscribe({ path: target, type: "file" })
+        const update = yield* updates.pipe(
+          Stream.take(1),
+          Stream.runHead,
+          Effect.forkScoped({ startImmediately: true }),
+        )
+        const creates = yield* Effect.suspend(() =>
+          fs.remove(target, { recursive: true, force: true }).pipe(Effect.andThen(fs.ensureDir(target))),
+        ).pipe(Effect.repeat(Schedule.spaced("10 millis")), Effect.forkScoped)
+        const event = yield* Fiber.join(update).pipe(Effect.ensuring(Fiber.interrupt(creates)))
 
-  it.live("ignores dependency, VCS, and build directories at any depth", () =>
-    withTmp(
-      (directory) =>
-        Effect.gen(function* () {
-          const afs = yield* FSUtil.Service
-          yield* ready(directory)
-          const roots = ["node_modules", ".git", "dist"].map((name) => path.join(directory, "nested", name))
-          const files = roots.map((root) => path.join(root, "package", "index.js"))
-          yield* noUpdate(
-            (event) => roots.some((root) => event.file === root || event.file.startsWith(`${root}${path.sep}`)),
-            Effect.forEach(files, (file) => afs.writeWithDirs(file, "ignored"), {
-              concurrency: "unbounded",
-              discard: true,
-            }),
-          )
-        }),
-      { vcs: "git" },
-    ),
-  )
-
-  it.live("cleanup stops publishing events", () =>
-    Effect.gen(function* () {
-      const bus = yield* Bus.Service
-      const fs = yield* FSUtil.Service
-      const tmp = yield* Effect.acquireRelease(
-        Effect.promise(() => tmpdir()),
-        (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]()),
-      )
-      yield* ready(tmp.path).pipe(
-        provide(tmp.path, { type: "git", store: AbsolutePath.make(path.join(tmp.path, ".git")) }),
-        Effect.scoped,
-      )
-      const file = path.join(tmp.path, "after-dispose.txt")
-      yield* noUpdate((event) => event.file === file, fs.writeFileString(file, "gone")).pipe(
-        Effect.provideService(Bus.Service, bus),
-      )
-    }).pipe(Effect.provide(AppNodeBuilder.build(LayerNode.group([FSUtil.node, Bus.node])))),
-  )
-
-  it.live("ignores .git/index changes", () =>
-    withTmp(
-      (directory) =>
-        Effect.gen(function* () {
-          const fs = yield* FSUtil.Service
-          const index = path.join(directory, ".git", "index")
-          yield* ready(directory)
-          yield* noUpdate(
-            (event) => event.file === index,
-            fs
-              .writeFileString(path.join(directory, "tracked.txt"), "a")
-              .pipe(Effect.andThen(Effect.promise(() => $`git add .`.cwd(directory).quiet())), Effect.asVoid),
-          )
-        }),
-      { vcs: "git" },
+        expect(event.valueOrUndefined?.path).toBe(target)
+      }).pipe(Effect.provide(AppNodeBuilder.build(Watcher.node))),
     ),
   )
 
@@ -374,11 +341,11 @@ describeWatcher("LocationWatcher", () => {
           const fs = yield* FSUtil.Service
           const head = path.join(directory, ".git", "HEAD")
           const branch = `watch-${Math.random().toString(36).slice(2)}`
-          yield* ready(directory)
+          yield* ready(head)
           yield* Effect.promise(() => $`git branch ${branch}`.cwd(directory).quiet())
           expect(
             yield* nextUpdate((event) => event.file === head, fs.writeFileString(head, `ref: refs/heads/${branch}\n`)),
-          ).toMatchObject({ file: head })
+          ).toEqual({ file: head, event: "change" })
         }),
       { vcs: "git" },
     ),
@@ -393,8 +360,8 @@ describeWatcher("LocationWatcher", () => {
             const afs = yield* FSUtil.Service
             const actual = path.join(directory, "..", `actual_${path.basename(directory)}`)
             yield* Effect.addFinalizer(() => Effect.promise(() => fs.rm(actual, { recursive: true, force: true })))
-            yield* ready(directory)
             const head = path.join(directory, ".git", "HEAD")
+            yield* ready(head, path.join(actual, "HEAD"))
             const branch = `watch-${Math.random().toString(36).slice(2)}`
             yield* Effect.promise(() => $`git branch ${branch}`.cwd(directory).quiet())
             expect(
@@ -422,7 +389,7 @@ describeWatcher("LocationWatcher", () => {
         Effect.gen(function* () {
           const fs = yield* FSUtil.Service
           const branch = path.join(directory, ".hg", "branch")
-          yield* ready(directory)
+          yield* ready(branch)
           expect(
             yield* nextUpdate((event) => event.file === branch, fs.writeFileString(branch, "feature\n")),
           ).toMatchObject({ file: branch })

packages/core/test/lib/environment-conformance.ts

@@ -105,19 +105,29 @@ export const environmentConformance = <E>(
       }),
     )
 
-    check("reports symlinks without resolving them", (harness) =>
+    check("preserves symlink metadata while following symlinks for content", (harness) =>
       Effect.gen(function* () {
         if (!harness.symlink) return
         yield* harness.files.write(`${harness.root}/target`, bytes("target"))
         yield* harness.files.write(`${harness.root}/target-dir/file`, bytes("through link"))
+        yield* harness.symlink("../target", `${harness.root}/target-dir/entry-link`)
         yield* harness.symlink("target", `${harness.root}/link`)
         yield* harness.symlink("target-dir", `${harness.root}/link-dir`)
+        yield* harness.symlink("missing", `${harness.root}/dangling-link`)
         expect((yield* harness.files.stat(`${harness.root}/link`)).type).toBe("symlink")
         expect(yield* harness.files.list(harness.root)).toContainEqual({ name: "link", type: "symlink" })
         expect(text((yield* harness.files.read(`${harness.root}/link-dir/file`)).bytes)).toBe("through link")
-        const listError = yield* Effect.flip(harness.files.list(`${harness.root}/link-dir`))
-        expect(listError).toBeInstanceOf(WrongKind)
-        expect((listError as WrongKind).actual).toBe("symlink")
+        expect(
+          (yield* harness.files.list(`${harness.root}/link-dir`)).toSorted((a, b) => a.name.localeCompare(b.name)),
+        ).toEqual([
+          { name: "entry-link", type: "symlink" },
+          { name: "file", type: "file" },
+        ])
+
+        const fileError = yield* Effect.flip(harness.files.list(`${harness.root}/link`))
+        expect(fileError).toBeInstanceOf(WrongKind)
+        expect((fileError as WrongKind).actual).toBe("file")
+        expect(yield* Effect.flip(harness.files.list(`${harness.root}/dangling-link`))).toBeInstanceOf(NotFound)
       }),
     )
 

packages/core/test/session-execution.test.ts

@@ -13,6 +13,7 @@ import { Session } from "@opencode-ai/core/session"
 import { SessionExecution } from "@opencode-ai/core/session/execution"
 import { SessionRestart } from "@opencode-ai/core/session/execution/restart"
 import { UserInterruptedError } from "@opencode-ai/core/session/error"
+import { SessionEvent } from "@opencode-ai/core/session/event"
 import { SessionRunner } from "@opencode-ai/core/session/runner"
 import { SessionTable } from "@opencode-ai/core/session/sql"
 import { SessionStore } from "@opencode-ai/core/session/store"
@@ -127,23 +128,34 @@ describe("SessionExecution lifecycle", () => {
   it.effect("resumes each suspended Session at most once", () =>
     Effect.gen(function* () {
       const database = yield* Database.Service
+      const bus = yield* Bus.Service
       const first = Session.ID.make("ses_resume_first")
       const second = Session.ID.make("ses_resume_second")
       yield* seedSessions(database, [first, second], { time_suspended: Date.now() })
 
       const drained: string[] = []
+      const continued: SessionEvent.Synthetic[] = []
       const scope = yield* Scope.make()
       const context = yield* buildExecution(scope, ({ sessionID }) => Effect.sync(() => void drained.push(sessionID)))
       const execution = Context.get(context, SessionExecution.Service)
       const restart = Context.get(context, SessionRestart.Service)
+      yield* bus.project(SessionEvent.Synthetic, (event) => Effect.sync(() => void continued.push(event)))
 
       yield* restart.resumeSuspendedSessions
       yield* Effect.forEach([first, second], execution.awaitIdle, { discard: true })
       expect(drained.toSorted()).toEqual([first, second])
+      expect(continued.map((event) => event.data).toSorted((a, b) => a.sessionID.localeCompare(b.sessionID))).toEqual(
+        [first, second].map((sessionID) => ({
+          sessionID,
+          text: "The server restarted while you were working. Continue from where you left off without repeating completed work.",
+          description: "Continuing after restart",
+        })),
+      )
       expect(yield* suspensions(database)).toEqual({ [first]: false, [second]: false })
 
       yield* restart.resumeSuspendedSessions
       expect(drained.length).toBe(2)
+      expect(continued.length).toBe(2)
       yield* Scope.close(scope, Exit.void)
     }),
   )

packages/core/test/session-runner-tool-registry.test.ts

@@ -3,10 +3,12 @@ import { Agent } from "@opencode-ai/core/agent"
 import type { Permission } from "@opencode-ai/core/permission"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
 import { Image } from "@opencode-ai/core/image"
+import { PluginHooks } from "@opencode-ai/core/plugin/hooks"
 import { Session } from "@opencode-ai/core/session"
 import { SessionMessage } from "@opencode-ai/core/session/message"
 import { Tool } from "@opencode-ai/core/tool"
 import type { Info } from "@opencode-ai/schema/tool"
+import { LayerNode } from "@opencode-ai/util/effect/layer-node"
 import { executeTool, toolDefinitions } from "./lib/tool"
 import { Cause, Deferred, Effect, Exit, Fiber, Layer, Option, Schema, SchemaGetter, SchemaIssue, Scope } from "effect"
 import { testEffect } from "./lib/effect"
@@ -26,10 +28,14 @@ const imageStore = Layer.mock(Image.Service, {
           maxBytes: 5,
         }),
       )
-    return Effect.succeed({ ...content, content: "bm9ybWFsaXplZA==", mime: "image/jpeg" })
+    return Effect.succeed({
+      ...content,
+      content: Buffer.from(`${Buffer.from(content.content, "base64").toString()} normalized`).toString("base64"),
+      mime: "image/jpeg",
+    })
   },
 })
-const registryLayer = AppNodeBuilder.build(Tool.node, [[Image.node, imageStore]])
+const registryLayer = AppNodeBuilder.build(LayerNode.group([Tool.node, PluginHooks.node]), [[Image.node, imageStore]])
 const it = testEffect(registryLayer)
 const identity = {
   agent: Agent.ID.make("build"),
@@ -344,7 +350,7 @@ describe("Tool", () => {
     }),
   )
 
-  it.effect("normalizes image tool output at execution and drops unresizable images", () =>
+  it.effect("normalizes image tool output once and drops unresizable images", () =>
     Effect.gen(function* () {
       const service = yield* Tool.Service
       yield* transform(service,
@@ -376,7 +382,12 @@ describe("Tool", () => {
 
       const execution = yield* executeTool(service, call("snapshot"))
       expect(execution.content).toEqual([
-        { type: "file", uri: "data:image/jpeg;base64,bm9ybWFsaXplZA==", mime: "image/jpeg", name: "frame.png" },
+        {
+          type: "file",
+          uri: "data:image/jpeg;base64,aW1hZ2Ugbm9ybWFsaXplZA==",
+          mime: "image/jpeg",
+          name: "frame.png",
+        },
         { type: "text", text: "snapshot" },
         { type: "text", text: "[1 image omitted: could not be decoded.]" },
         { type: "text", text: "[1 image omitted: could not be resized below the image size limit.]" },
@@ -384,6 +395,34 @@ describe("Tool", () => {
     }),
   )
 
+  it.effect("normalizes image content added by an after hook", () =>
+    Effect.gen(function* () {
+      const service = yield* Tool.Service
+      const hooks = yield* PluginHooks.Service
+      yield* transform(service, { hooked: constant("original") }, { codemode: false })
+      yield* hooks.register("tool", "execute.after", (event) =>
+        Effect.sync(() => {
+          if (event.status !== "completed") return
+          event.result = {
+            ...event.result,
+            content: [
+              { type: "file", uri: "data:image/png;base64,aW1hZ2U=", mime: "image/png", name: "hook.png" },
+            ],
+          }
+        }),
+      )
+
+      expect((yield* executeTool(service, call("hooked"))).content).toEqual([
+        {
+          type: "file",
+          uri: "data:image/jpeg;base64,aW1hZ2Ugbm9ybWFsaXplZA==",
+          mime: "image/jpeg",
+          name: "hook.png",
+        },
+      ])
+    }),
+  )
+
   it.effect("publishes progress metadata unchanged", () =>
     Effect.gen(function* () {
       const service = yield* Tool.Service

packages/core/test/skill.test.ts

@@ -6,11 +6,10 @@ import { Agent } from "@opencode-ai/core/agent"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
 import { Bus } from "@opencode-ai/core/bus"
-import { FSUtil } from "@opencode-ai/util/fs-util"
 import { AbsolutePath } from "@opencode-ai/core/schema"
 import { Skill } from "@opencode-ai/core/skill"
 import { SkillDiscovery } from "@opencode-ai/core/skill/discovery"
-import { FileSystem } from "@opencode-ai/schema/filesystem"
+import { Watcher } from "@opencode-ai/core/filesystem/watcher"
 import { tmpdir } from "./fixture/tmpdir"
 import { testEffect } from "./lib/effect"
 
@@ -25,8 +24,15 @@ const discovery = Layer.succeed(
     },
   }),
 )
+const watcherLayer = Watcher.testLayer
 const it = testEffect(
-  AppNodeBuilder.build(LayerNode.group([Skill.node, Agent.node, Bus.node]), [[SkillDiscovery.node, discovery]]),
+  Layer.mergeAll(
+    AppNodeBuilder.build(LayerNode.group([Skill.node, Agent.node, Bus.node]), [
+      [SkillDiscovery.node, discovery],
+      [Watcher.node, watcherLayer],
+    ]),
+    watcherLayer,
+  ),
 )
 
 function write(directory: string, name: string, description: string) {
@@ -53,6 +59,24 @@ function waitForSkillUpdate() {
   })
 }
 
+function expectSubscription(check: (input: Watcher.WatchInput) => boolean) {
+  return Effect.gen(function* () {
+    const watcher = yield* Watcher.Test
+    expect((yield* watcher.subscriptions()).some(check)).toBe(true)
+  })
+}
+
+function emitAndWait(update: Watcher.Update) {
+  return Effect.gen(function* () {
+    const watcher = yield* Watcher.Test
+    yield* Effect.acquireUseRelease(
+      waitForSkillUpdate(),
+      ({ deferred }) => watcher.emit(update).pipe(Effect.andThen(Deferred.await(deferred)), Effect.timeout("1 second")),
+      ({ fiber }) => Fiber.interrupt(fiber),
+    )
+  })
+}
+
 describe("Skill", () => {
   it.live("publishes updates when skill sources change", () =>
     Effect.gen(function* () {
@@ -89,6 +113,7 @@ describe("Skill", () => {
           })
 
           const skill = yield* Skill.Service
+          const watcher = yield* Watcher.Test
           yield* skill.transform((editor) => {
             editor.source({ type: "directory", path: AbsolutePath.make(first) })
             editor.source({ type: "directory", path: AbsolutePath.make(first) })
@@ -119,6 +144,21 @@ describe("Skill", () => {
               content: "# review",
             },
           ])
+          expect(yield* watcher.subscriptions()).toEqual([
+            { path: first, type: "directory" },
+            { path: second, type: "directory" },
+          ])
+
+          yield* Effect.promise(() => write(second, "review", "Updated Second"))
+          yield* emitAndWait({ type: "update", path: path.join(second, "review", "SKILL.md") })
+
+          expect((yield* skill.list()).find((item) => item.id === "review")?.description).toBe("Updated Second")
+          expect(yield* watcher.subscriptions()).toEqual([
+            { path: first, type: "directory" },
+            { path: second, type: "directory" },
+            { path: first, type: "directory" },
+            { path: second, type: "directory" },
+          ])
         }),
       ),
     ),
@@ -198,7 +238,7 @@ metadata:
     ),
   )
 
-  it.live("invalidates cached skills and publishes updates for watcher changes", () =>
+  it.live("clears cached skills when sources reload", () =>
     Effect.acquireRelease(
       Effect.promise(() => tmpdir()),
       (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]()),
@@ -210,26 +250,187 @@ metadata:
             await write(tmp.path, "deploy", "Initial deploy")
           })
 
+          const skill = yield* Skill.Service
+          const watcher = yield* Watcher.Test
           const bus = yield* Bus.Service
+          yield* skill.transform((editor) => editor.source({ type: "directory", path: AbsolutePath.make(tmp.path) }))
+          expect((yield* skill.list()).find((item) => item.id === "deploy")?.description).toBe("Initial deploy")
+          expect(yield* watcher.subscriptions()).toEqual([{ path: tmp.path, type: "directory" }])
+
+          let refreshed: Skill.Info[] = []
+          const unsubscribe = yield* bus.listen((event) => {
+            if (event.type !== Skill.Event.Updated.type) return Effect.void
+            return skill.list().pipe(
+              Effect.tap((items) => Effect.sync(() => (refreshed = items))),
+              Effect.asVoid,
+            )
+          })
+
+          yield* Effect.promise(() => write(tmp.path, "deploy", "Updated deploy"))
+          yield* skill.reload().pipe(Effect.timeout("1 second"))
+          yield* unsubscribe
+
+          expect(refreshed.find((item) => item.id === "deploy")?.description).toBe("Updated deploy")
+          expect(yield* watcher.subscriptions()).toEqual([
+            { path: tmp.path, type: "directory" },
+            { path: tmp.path, type: "directory" },
+          ])
+        }),
+      ),
+    ),
+  )
+
+  it.live("reloads project sources created after their missing parent", () =>
+    Effect.acquireRelease(
+      Effect.promise(() => tmpdir()),
+      (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]()),
+    ).pipe(
+      Effect.flatMap((tmp) =>
+        Effect.gen(function* () {
+          const source = path.join(tmp.path, "generated", "skills")
+          const file = path.join(source, "deploy", "SKILL.md")
+          const skill = yield* Skill.Service
+          const watcher = yield* Watcher.Test
+          yield* skill.transform((editor) => editor.source({ type: "directory", path: AbsolutePath.make(source) }))
+          expect(yield* skill.list()).toEqual([])
+          expect(yield* watcher.subscriptions()).toEqual([{ path: path.join(tmp.path, "generated"), type: "file" }])
+
+          yield* Effect.promise(() => fs.mkdir(path.join(tmp.path, "generated")))
+          yield* emitAndWait({ type: "create", path: path.join(tmp.path, "generated") })
+          expect(yield* skill.list()).toEqual([])
+          expect(yield* watcher.subscriptions()).toEqual([
+            { path: path.join(tmp.path, "generated"), type: "file" },
+            { path: source, type: "file" },
+          ])
+
+          yield* Effect.promise(async () => {
+            await fs.mkdir(path.dirname(file), { recursive: true })
+            await write(source, "deploy", "Deploy production")
+          })
+          yield* emitAndWait({ type: "create", path: source })
+
+          expect((yield* skill.list()).map((item) => item.id)).toEqual([Skill.ID.make("deploy")])
+          expect(yield* watcher.subscriptions()).toEqual([
+            { path: path.join(tmp.path, "generated"), type: "file" },
+            { path: source, type: "file" },
+            { path: source, type: "directory" },
+          ])
+        }),
+      ),
+    ),
+  )
+
+  it.live("watches directory sources for added and changed skills", () =>
+    Effect.acquireRelease(
+      Effect.promise(() => tmpdir()),
+      (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]()),
+    ).pipe(
+      Effect.flatMap((tmp) =>
+        Effect.gen(function* () {
+          yield* Effect.promise(async () => {
+            await fs.mkdir(path.join(tmp.path, "deploy"), { recursive: true })
+            await write(tmp.path, "deploy", "Initial deploy")
+          })
+
           const skill = yield* Skill.Service
           yield* skill.transform((editor) => editor.source({ type: "directory", path: AbsolutePath.make(tmp.path) }))
+          expect((yield* skill.list()).map((item) => item.id)).toEqual([Skill.ID.make("deploy")])
+          yield* expectSubscription((input) => input.type === "directory" && input.path === tmp.path)
 
-          expect((yield* skill.list()).find((item) => item.name === "deploy")?.description).toBe("Initial deploy")
-
-          const file = path.join(tmp.path, "deploy", "SKILL.md")
+          const deploy = path.join(tmp.path, "deploy", "SKILL.md")
           yield* Effect.promise(() => write(tmp.path, "deploy", "Updated deploy"))
-          expect((yield* skill.list()).find((item) => item.name === "deploy")?.description).toBe("Initial deploy")
+          yield* emitAndWait({ type: "update", path: deploy })
+          expect((yield* skill.list()).find((item) => item.id === "deploy")?.description).toBe("Updated deploy")
 
-          yield* Effect.acquireUseRelease(
-            waitForSkillUpdate(),
-            ({ deferred }) =>
-              bus
-                .publish(FileSystem.Event.Changed, { file, event: "change" })
-                .pipe(Effect.andThen(Deferred.await(deferred)), Effect.timeout("1 second")),
-            ({ fiber }) => Fiber.interrupt(fiber),
-          )
+          yield* Effect.promise(async () => {
+            await fs.mkdir(path.join(tmp.path, "review"), { recursive: true })
+            await write(tmp.path, "review", "Review changes")
+          })
+          const review = path.join(tmp.path, "review", "SKILL.md")
+          yield* emitAndWait({ type: "create", path: review })
+          expect((yield* skill.list()).map((item) => item.id)).toEqual([
+            Skill.ID.make("deploy"),
+            Skill.ID.make("review"),
+          ])
 
-          expect((yield* skill.list()).find((item) => item.name === "deploy")?.description).toBe("Updated deploy")
+          yield* Effect.promise(() => fs.rm(path.join(tmp.path, "review"), { recursive: true }))
+          yield* emitAndWait({ type: "delete", path: review })
+          expect((yield* skill.list()).map((item) => item.id)).toEqual([Skill.ID.make("deploy")])
+        }),
+      ),
+    ),
+  )
+
+  it.live("watches canonical directories behind symlinked skills", () =>
+    Effect.acquireRelease(
+      Effect.promise(() => tmpdir()),
+      (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]()),
+    ).pipe(
+      Effect.flatMap((tmp) =>
+        Effect.gen(function* () {
+          const source = path.join(tmp.path, "source")
+          const target = path.join(tmp.path, "target", "bro")
+          const file = path.join(target, "SKILL.md")
+          yield* Effect.promise(async () => {
+            await fs.mkdir(source, { recursive: true })
+            await fs.mkdir(target, { recursive: true })
+            await fs.writeFile(file, "---\nname: bro\ndescription: Initial\n---\n# bro")
+            await fs.symlink(target, path.join(source, "bro"))
+          })
+
+          const skill = yield* Skill.Service
+          yield* skill.transform((editor) => editor.source({ type: "directory", path: AbsolutePath.make(source) }))
+          expect((yield* skill.list()).find((item) => item.id === "bro")?.description).toBe("Initial")
+          yield* expectSubscription((input) => input.type === "directory" && input.path === target)
+
+          yield* Effect.promise(() => fs.writeFile(file, "---\nname: bro\ndescription: Updated\n---\n# bro"))
+          yield* emitAndWait({ type: "update", path: file })
+          expect((yield* skill.list()).find((item) => item.id === "bro")?.description).toBe("Updated")
+        }),
+      ),
+    ),
+  )
+
+  it.live("invalidates symlinked sources when their target changes", () =>
+    Effect.acquireRelease(
+      Effect.promise(() => tmpdir()),
+      (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]()),
+    ).pipe(
+      Effect.flatMap((tmp) =>
+        Effect.gen(function* () {
+          const source = path.join(tmp.path, "source")
+          const first = path.join(tmp.path, "first")
+          const second = path.join(tmp.path, "second")
+          yield* Effect.promise(async () => {
+            await fs.mkdir(path.join(first, "bro"), { recursive: true })
+            await fs.mkdir(path.join(second, "bro"), { recursive: true })
+            await write(first, "bro", "First")
+            await write(second, "bro", "Second")
+            await fs.symlink(first, source)
+          })
+
+          const skill = yield* Skill.Service
+          const watcher = yield* Watcher.Test
+          yield* skill.transform((editor) => editor.source({ type: "directory", path: AbsolutePath.make(source) }))
+          expect((yield* skill.list()).find((item) => item.id === "bro")?.description).toBe("First")
+          expect(yield* watcher.subscriptions()).toEqual([
+            { path: first, type: "directory" },
+            { path: source, type: "file" },
+          ])
+
+          yield* Effect.promise(async () => {
+            await fs.unlink(source)
+            await fs.symlink(second, source)
+          })
+          yield* emitAndWait({ type: "update", path: source })
+
+          expect((yield* skill.list()).find((item) => item.id === "bro")?.description).toBe("Second")
+          expect(yield* watcher.subscriptions()).toEqual([
+            { path: first, type: "directory" },
+            { path: source, type: "file" },
+            { path: second, type: "directory" },
+            { path: source, type: "file" },
+          ])
         }),
       ),
     ),

packages/core/test/tool-edit.test.ts

@@ -4,9 +4,9 @@ import { describe, expect } from "bun:test"
 import { Effect, Layer } from "effect"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
+import { Environment } from "@opencode-ai/core/environment"
 import { FileMutation } from "@opencode-ai/core/file-mutation"
 import { Formatter } from "@opencode-ai/core/formatter"
-import { FSUtil } from "@opencode-ai/util/fs-util"
 import { Location } from "@opencode-ai/core/location"
 import { LocationMutation } from "@opencode-ai/core/location-mutation"
 import { Permission } from "@opencode-ai/core/permission"
@@ -23,7 +23,15 @@ import { toolIdentity, executeTool, registerToolPlugin, toolDefinitions } from "
 const editToolNode = makeLocationNode({
   name: "test/edit-tool-plugin",
   layer: Layer.effectDiscard(registerToolPlugin(EditTool.Plugin)),
-  deps: [Tool.node, LocationMutation.node, FileMutation.node, Formatter.node, FSUtil.node, Permission.node],
+  deps: [
+    Tool.node,
+    LocationMutation.node,
+    FileMutation.node,
+    Environment.node,
+    Formatter.node,
+    Location.node,
+    Permission.node,
+  ],
 })
 
 const sessionID = Session.ID.make("ses_edit_tool_test")
@@ -72,29 +80,28 @@ const reset = () => {
   formatFile = () => Effect.succeed(false)
 }
 
-const filesystem = Layer.effect(
-  FSUtil.Service,
+const environment = Layer.effect(
+  Environment.Service,
   Effect.gen(function* () {
-    const fs = yield* FSUtil.Service
-    return FSUtil.Service.of({
-      ...fs,
-      readFile: (target) =>
-        fs
-          .readFile(target)
-          .pipe(
-            Effect.tap((content) =>
-              Effect.sync(() => reads++).pipe(Effect.andThen(Effect.suspend(() => afterRead(target, content)))),
+    const current = yield* Environment.Service
+    return Environment.Service.of({
+      ...current,
+      files: {
+        ...current.files,
+        read: (target, range) =>
+          current.files
+            .read(target, range)
+            .pipe(
+              Effect.tap((result) =>
+                Effect.sync(() => reads++).pipe(Effect.andThen(Effect.suspend(() => afterRead(target, result.bytes)))),
+              ),
             ),
-          ),
-      writeWithDirs: (target, content, mode) =>
-        Effect.sync(() => writes.push(target)).pipe(Effect.andThen(fs.writeWithDirs(target, content, mode))),
-      writeFile: (target, content, options) =>
-        Effect.sync(() => writes.push(target)).pipe(Effect.andThen(fs.writeFile(target, content, options))),
-      writeFileString: (target, content, options) =>
-        Effect.sync(() => writes.push(target)).pipe(Effect.andThen(fs.writeFileString(target, content, options))),
+        write: (target, content) =>
+          Effect.sync(() => writes.push(target)).pipe(Effect.andThen(current.files.write(target, content))),
+      },
     })
   }),
-).pipe(Layer.provide(LayerNode.compile(FSUtil.node)))
+).pipe(Layer.provide(LayerNode.compile(Environment.node)))
 
 const withTool = <A, E, R>(directory: string, body: (registry: Tool.Interface) => Effect.Effect<A, E, R>) => {
   const activeLocation = Layer.succeed(
@@ -106,15 +113,9 @@ const withTool = <A, E, R>(directory: string, body: (registry: Tool.Interface) =
   }).pipe(
     Effect.provide(
       AppNodeBuilder.build(
-        LayerNode.group([
-          Tool.node,
-          Tool.node,
-          LocationMutation.node,
-          FileMutation.node,
-          editToolNode,
-        ]),
+        LayerNode.group([Tool.node, Tool.node, LocationMutation.node, FileMutation.node, editToolNode]),
         [
-          [FSUtil.node, filesystem],
+          [Environment.node, environment],
           [Location.node, activeLocation],
           [Formatter.node, formatter],
           [Permission.node, permission],
@@ -471,10 +472,7 @@ describe("EditTool", () => {
             withTool(tmp.path, (registry) =>
               Effect.gen(function* () {
                 expect(
-                  yield* executeTool(
-                    registry,
-                    call({ path: "missing.ts", oldString: "before", newString: "after" }),
-                  ),
+                  yield* executeTool(registry, call({ path: "missing.ts", oldString: "before", newString: "after" })),
                 ).toEqual({
                   status: "error",
                   error: { type: "tool.execution", message: "File not found: missing.ts" },
@@ -645,6 +643,43 @@ describe("EditTool", () => {
     ),
   )
 
+  it.live("serializes concurrent edit transactions", () =>
+    Effect.acquireUseRelease(
+      Effect.promise(() => tmpdir()),
+      (tmp) => {
+        reset()
+        const target = path.join(tmp.path, "concurrent.txt")
+        afterRead = () => (reads === 1 ? Effect.sleep("50 millis") : Effect.void)
+        return Effect.promise(() => fs.writeFile(target, "one\ntwo\n")).pipe(
+          Effect.andThen(
+            withTool(tmp.path, (registry) =>
+              Effect.all(
+                [
+                  executeTool(
+                    registry,
+                    call({ path: "concurrent.txt", oldString: "one", newString: "ONE" }, "call-edit-one"),
+                  ),
+                  executeTool(
+                    registry,
+                    call({ path: "concurrent.txt", oldString: "two", newString: "TWO" }, "call-edit-two"),
+                  ),
+                ],
+                { concurrency: "unbounded" },
+              ),
+            ),
+          ),
+          Effect.andThen((results) =>
+            Effect.gen(function* () {
+              expect(results.map((result) => result.status)).toEqual(["completed", "completed"])
+              expect(yield* Effect.promise(() => fs.readFile(target, "utf8"))).toBe("ONE\nTWO\n")
+            }),
+          ),
+        )
+      },
+      (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]()),
+    ),
+  )
+
   it.live("applies the edit when content changes after matching", () =>
     Effect.acquireUseRelease(
       Effect.promise(() => tmpdir()),

packages/core/test/tool-patch.test.ts

@@ -2,11 +2,12 @@ import fs from "fs/promises"
 import path from "path"
 import { describe, expect } from "bun:test"
 import { Effect, Exit, Layer, Schema } from "effect"
-import { systemError } from "effect/PlatformError"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
+import { Environment } from "@opencode-ai/core/environment"
 import { FSUtil } from "@opencode-ai/util/fs-util"
 import { Formatter } from "@opencode-ai/core/formatter"
+import { FileMutation } from "@opencode-ai/core/file-mutation"
 import { Location } from "@opencode-ai/core/location"
 import { Permission } from "@opencode-ai/core/permission"
 import { AbsolutePath } from "@opencode-ai/core/schema"
@@ -22,7 +23,7 @@ import { toolIdentity, executeTool, registerToolPlugin, toolDefinitions } from "
 const patchToolNode = makeLocationNode({
   name: "test/patch-tool-plugin",
   layer: Layer.effectDiscard(registerToolPlugin(PatchTool.Plugin)),
-  deps: [Tool.node, Formatter.node, FSUtil.node, Location.node, Permission.node],
+  deps: [Tool.node, FileMutation.node, Environment.node, Formatter.node, Location.node, Permission.node],
 })
 
 const sessionID = Session.ID.make("ses_patch_tool_test")
@@ -81,48 +82,33 @@ const reset = () => {
   formatFile = () => Effect.succeed(false)
 }
 
-const filesystem = Layer.effect(
-  FSUtil.Service,
+const environment = Layer.effect(
+  Environment.Service,
   Effect.gen(function* () {
-    const fs = yield* FSUtil.Service
-    return FSUtil.Service.of({
-      ...fs,
-      readFile: (target) =>
-        Effect.sync(() => {
-          if (!editApproved) readsBeforeEditApproval++
-        }).pipe(Effect.andThen(fs.readFile(target))),
-      remove: (target, options) => {
-        if (failRemoveTarget && path.basename(target) === failRemoveTarget) return Effect.die("forced remove failure")
-        if (failRemoveErrorTarget && path.basename(target) === failRemoveErrorTarget) {
-          return Effect.fail(
-            systemError({
-              _tag: "Unknown",
-              module: "FileSystem",
-              method: "remove",
-              description: "forced remove failure",
-              pathOrDescriptor: target,
-            }),
-          )
-        }
-        return fs.remove(target, options)
-      },
-      writeWithDirs: (target, content, mode) => {
-        if (failWriteTarget && path.basename(target) === failWriteTarget) {
-          return Effect.fail(
-            systemError({
-              _tag: "Unknown",
-              module: "FileSystem",
-              method: "writeWithDirs",
-              description: "forced write failure",
-              pathOrDescriptor: target,
-            }),
-          )
-        }
-        return fs.writeWithDirs(target, content, mode)
+    const current = yield* Environment.Service
+    return Environment.Service.of({
+      ...current,
+      files: {
+        ...current.files,
+        read: (target, range) =>
+          Effect.sync(() => {
+            if (!editApproved) readsBeforeEditApproval++
+          }).pipe(Effect.andThen(current.files.read(target, range))),
+        remove: (target) => {
+          if (failRemoveTarget && path.basename(target) === failRemoveTarget) return Effect.die("forced remove failure")
+          if (failRemoveErrorTarget && path.basename(target) === failRemoveErrorTarget)
+            return Effect.fail(new Environment.Failed({ path: target, cause: new Error("forced remove failure") }))
+          return current.files.remove(target)
+        },
+        write: (target, content) => {
+          if (failWriteTarget && path.basename(target) === failWriteTarget)
+            return Effect.fail(new Environment.Failed({ path: target, cause: new Error("forced write failure") }))
+          return current.files.write(target, content)
+        },
       },
     })
   }),
-).pipe(Layer.provide(LayerNode.compile(FSUtil.node)))
+).pipe(Layer.provide(LayerNode.compile(Environment.node)))
 
 const withTool = <A, E, R>(
   directory: string,
@@ -139,8 +125,8 @@ const withTool = <A, E, R>(
     return yield* body(yield* Tool.Service)
   }).pipe(
     Effect.provide(
-      AppNodeBuilder.build(LayerNode.group([Tool.node, patchToolNode]), [
-        [FSUtil.node, filesystem],
+      AppNodeBuilder.build(LayerNode.group([Tool.node, FileMutation.node, patchToolNode]), [
+        [Environment.node, environment],
         [Location.node, activeLocation],
         [Formatter.node, formatter],
         [Permission.node, permission],
@@ -262,6 +248,43 @@ describe("PatchTool", () => {
     ),
   )
 
+  it.live("serializes concurrent patch transactions", () =>
+    withTempTool((directory, registry) => {
+      const target = path.join(directory, "concurrent.txt")
+      afterEditApproval = () =>
+        assertions.filter((input) => input.action === "edit").length === 1 ? Effect.sleep("50 millis") : Effect.void
+      return Effect.promise(() => fs.writeFile(target, "one\ntwo\n")).pipe(
+        Effect.andThen(
+          Effect.all(
+            [
+              executeTool(
+                registry,
+                call(
+                  "*** Begin Patch\n*** Update File: concurrent.txt\n@@\n-one\n+ONE\n*** End Patch",
+                  "call-patch-one",
+                ),
+              ),
+              executeTool(
+                registry,
+                call(
+                  "*** Begin Patch\n*** Update File: concurrent.txt\n@@\n-two\n+TWO\n*** End Patch",
+                  "call-patch-two",
+                ),
+              ),
+            ],
+            { concurrency: "unbounded" },
+          ),
+        ),
+        Effect.andThen((results) =>
+          Effect.gen(function* () {
+            expect(results.map((result) => result.status)).toEqual(["completed", "completed"])
+            expect(yield* Effect.promise(() => fs.readFile(target, "utf8"))).toBe("ONE\nTWO\n")
+          }),
+        ),
+      )
+    }),
+  )
+
   it.live("returns file diffs for final formatted content", () =>
     withTempTool((directory, registry) => {
       const target = path.join(directory, "formatted.txt")

packages/core/test/tool-read-filesystem.test.ts

@@ -1,66 +1,65 @@
 import { describe, expect } from "bun:test"
 import fs from "fs/promises"
 import path from "path"
-import { Effect, FileSystem } from "effect"
+import { Environment } from "@opencode-ai/core/environment"
+import { AbsolutePath } from "@opencode-ai/core/schema"
+import { ReadToolFileSystem } from "@opencode-ai/core/tool/read-filesystem"
+import { CrossSpawnSpawner } from "@opencode-ai/util/cross-spawn-spawner"
 import { LayerNodePlatform } from "@opencode-ai/util/effect/app-node-platform"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
-import { FSUtil } from "@opencode-ai/util/fs-util"
-import { ReadToolFileSystem } from "@opencode-ai/core/tool/read-filesystem"
+import { Effect, FileSystem } from "effect"
+import { ChildProcessSpawner } from "effect/unstable/process"
 import { testEffect } from "./lib/effect"
 
-const it = testEffect(LayerNode.compile(LayerNode.group([FSUtil.node, LayerNodePlatform.filesystem])))
+const it = testEffect(LayerNode.compile(LayerNode.group([CrossSpawnSpawner.node, LayerNodePlatform.filesystem])))
 const fixture = Effect.gen(function* () {
-  const fs = yield* FSUtil.Service
   const files = yield* FileSystem.FileSystem
+  const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
   const directory = yield* files.makeTempDirectoryScoped()
-  return { fs, files, directory }
+  return { environment: Environment.makeFiles(Environment.makeLocalDriver(spawner)), files, directory }
 })
+const absolute = (value: string) => AbsolutePath.make(value)
 
 describe("ReadToolFileSystem", () => {
-  it.effect("fails with a typed filesystem error when a resolved file disappears", () =>
+  it.effect("preserves the environment not-found error", () =>
     Effect.gen(function* () {
-      const { fs, directory } = yield* fixture
+      const { environment, directory } = yield* fixture
       const file = path.join(directory, "missing.txt")
 
-      const error = yield* ReadToolFileSystem.read(fs, file, "missing.txt").pipe(Effect.flip)
+      const error = yield* ReadToolFileSystem.read(environment, absolute(file), "missing.txt").pipe(Effect.flip)
 
-      expect(error).toMatchObject({ _tag: "PlatformError" })
+      expect(error).toBeInstanceOf(Environment.NotFound)
     }),
   )
 
-  it.effect("fails when a file becomes the wrong path kind", () =>
+  it.effect("returns a listing when read reports a directory", () =>
     Effect.gen(function* () {
-      const { fs, directory } = yield* fixture
+      const { environment, files, directory } = yield* fixture
+      yield* files.makeDirectory(path.join(directory, "folder"))
+      yield* files.writeFileString(path.join(directory, "file.txt"), "hello")
 
-      const error = yield* ReadToolFileSystem.read(fs, directory, "folder").pipe(Effect.flip)
+      const result = yield* ReadToolFileSystem.read(environment, absolute(directory), "folder")
 
-      expect(error).toBeInstanceOf(ReadToolFileSystem.PathKindError)
-    }),
-  )
-
-  it.effect("fails with a typed filesystem error when directory listing fails", () =>
-    Effect.gen(function* () {
-      const { fs, files, directory } = yield* fixture
-      const file = path.join(directory, "file.txt")
-      yield* files.writeFileString(file, "hello")
-
-      const error = yield* ReadToolFileSystem.list(fs, file).pipe(Effect.flip)
-
-      expect(error).toBeInstanceOf(FSUtil.FileSystemError)
-      if (error instanceof FSUtil.FileSystemError) expect(error.method).toBe("readDirectoryEntries")
+      expect(result).toMatchObject({
+        type: "list-page",
+        entries: [
+          { path: `folder${path.sep}`, type: "directory" },
+          { path: "file.txt", type: "file" },
+        ],
+      })
     }),
   )
 
   it.effect("reads malformed UTF-8 lossily and still rejects null-byte binary content", () =>
     Effect.gen(function* () {
-      const { fs, files, directory } = yield* fixture
+      const { environment, files, directory } = yield* fixture
       const binary = path.join(directory, "archive.dat")
       const malformed = path.join(directory, "malformed.txt")
       yield* files.writeFile(binary, Uint8Array.of(0, 1, 2, 3))
       yield* files.writeFile(malformed, Uint8Array.of(0x68, 0x69, 0x80))
 
-      const binaryError = yield* ReadToolFileSystem.read(fs, binary, "archive.dat").pipe(Effect.flip)
-      const malformedResult = yield* ReadToolFileSystem.read(fs, malformed, "malformed.txt")
+      const binaryError = yield* ReadToolFileSystem.read(environment, absolute(binary), "archive.dat").pipe(Effect.flip)
+      const malformedResult = yield* ReadToolFileSystem.read(environment, absolute(malformed), "malformed.txt")
 
       expect(binaryError).toBeInstanceOf(ReadToolFileSystem.BinaryFileError)
       expect(binaryError.message).toBe("Cannot read binary file: archive.dat")
@@ -70,11 +69,11 @@ describe("ReadToolFileSystem", () => {
 
   it.effect("reads text despite a binary-associated extension", () =>
     Effect.gen(function* () {
-      const { fs, files, directory } = yield* fixture
+      const { environment, files, directory } = yield* fixture
       const file = path.join(directory, "notes.docx")
       yield* files.writeFileString(file, "plain text")
 
-      const result = yield* ReadToolFileSystem.read(fs, file, "notes.docx")
+      const result = yield* ReadToolFileSystem.read(environment, absolute(file), "notes.docx")
 
       expect(result).toMatchObject({ type: "file", content: "plain text", encoding: "utf8" })
     }),
@@ -83,15 +82,17 @@ describe("ReadToolFileSystem", () => {
   it.effect("lists unresolved symlinks, including broken and escaping links", () =>
     Effect.gen(function* () {
       if (process.platform === "win32") return
-      const { fs: service, files, directory } = yield* fixture
+      const { environment, files, directory } = yield* fixture
       const outside = yield* files.makeTempDirectoryScoped()
       yield* files.makeDirectory(path.join(directory, "folder"))
       yield* files.writeFileString(path.join(directory, "file.txt"), "hello")
       yield* Effect.promise(() => fs.symlink(path.join(outside, "target.txt"), path.join(directory, "escape")))
       yield* Effect.promise(() => fs.symlink(path.join(directory, "missing.txt"), path.join(directory, "broken")))
 
-      const result = yield* ReadToolFileSystem.list(service, directory)
+      const result = yield* ReadToolFileSystem.read(environment, absolute(directory), "folder")
 
+      expect(result.type).toBe("list-page")
+      if (result.type !== "list-page") return
       expect(result.entries.map((entry) => ({ ...entry, path: String(entry.path) }))).toEqual([
         { path: `folder${path.sep}`, type: "directory" },
         { path: "broken", type: "symlink" },
@@ -101,45 +102,154 @@ describe("ReadToolFileSystem", () => {
     }),
   )
 
+  it.effect("reads a symlinked directory as a listing", () =>
+    Effect.gen(function* () {
+      if (process.platform === "win32") return
+      const { environment, files, directory } = yield* fixture
+      const target = path.join(directory, "target")
+      const link = path.join(directory, "link")
+      yield* files.makeDirectory(target)
+      yield* files.writeFileString(path.join(target, "file.txt"), "hello")
+      yield* Effect.promise(() => fs.symlink(target, link))
+
+      const result = yield* ReadToolFileSystem.read(environment, absolute(link), "link")
+
+      expect(result).toMatchObject({
+        type: "list-page",
+        entries: [{ path: "file.txt", type: "file" }],
+      })
+    }),
+  )
+
   it.effect("reports out-of-range pagination as a typed error", () =>
     Effect.gen(function* () {
-      const { fs, files, directory } = yield* fixture
+      const { environment, files, directory } = yield* fixture
       const file = path.join(directory, "short.txt")
       yield* files.writeFileString(file, "one\n")
 
-      const error = yield* ReadToolFileSystem.read(fs, file, "short.txt", { offset: 2 }).pipe(Effect.flip)
+      const error = yield* ReadToolFileSystem.read(environment, absolute(file), "short.txt", { offset: 2 }).pipe(
+        Effect.flip,
+      )
 
       expect(error).toBeInstanceOf(ReadToolFileSystem.OffsetOutOfRangeError)
       expect(error.message).toBe("Offset 2 is out of range")
     }),
   )
 
-  it.effect("stops reading after the requested page is complete", () =>
+  it.effect("pages text with one-based offsets", () =>
     Effect.gen(function* () {
-      const { fs, files, directory } = yield* fixture
-      const prefix = new TextEncoder().encode("one\n")
-      for (const [name, trailing] of [
-        ["malformed.txt", 0x80],
-        ["nul.txt", 0],
-      ] as const) {
-        const file = path.join(directory, name)
-        yield* files.writeFile(file, Uint8Array.from([...prefix, trailing]))
+      const { environment, files, directory } = yield* fixture
+      const file = path.join(directory, "lines.txt")
+      yield* files.writeFileString(file, "one\r\ntwo\nthree")
 
-        const result = yield* ReadToolFileSystem.read(fs, file, name, { limit: 1 })
+      const result = yield* ReadToolFileSystem.read(environment, absolute(file), "lines.txt", {
+        offset: 2,
+        limit: 1,
+      })
 
-        expect(result).toMatchObject({ type: "text-page", content: "one", truncated: true, next: 2 })
+      expect(result).toMatchObject({ type: "text-page", content: "two", offset: 2, truncated: true, next: 3 })
+    }),
+  )
+
+  it.effect("truncates long lines", () =>
+    Effect.gen(function* () {
+      const { environment, files, directory } = yield* fixture
+      const file = path.join(directory, "long.txt")
+      yield* files.writeFileString(file, "a".repeat(2_001))
+
+      const result = yield* ReadToolFileSystem.read(environment, absolute(file), "long.txt", { limit: 1 })
+
+      expect(result).toMatchObject({
+        type: "text-page",
+        content: `${"a".repeat(2_000)}... (line truncated to 2000 chars)`,
+        truncated: false,
+      })
+    }),
+  )
+
+  it.effect("enforces line and byte budgets with continuation offsets", () =>
+    Effect.gen(function* () {
+      const { environment, files, directory } = yield* fixture
+      const linesFile = path.join(directory, "many-lines.txt")
+      const bytesFile = path.join(directory, "many-bytes.txt")
+      yield* files.writeFileString(linesFile, Array.from({ length: 2_001 }, (_, index) => String(index)).join("\n"))
+      yield* files.writeFileString(bytesFile, Array.from({ length: 200 }, () => "a".repeat(2_000)).join("\n"))
+      const ranges: Array<{ readonly offset: number; readonly length: number } | undefined> = []
+      const tracked = {
+        ...environment,
+        read: (path: string, range?: { readonly offset: number; readonly length: number }) =>
+          Effect.sync(() => ranges.push(range)).pipe(Effect.andThen(environment.read(path, range))),
       }
+
+      const lines = yield* ReadToolFileSystem.read(environment, absolute(linesFile), "many-lines.txt", { limit: 2_000 })
+      const bytes = yield* ReadToolFileSystem.read(tracked, absolute(bytesFile), "many-bytes.txt", {})
+
+      expect(lines).toMatchObject({ type: "text-page", truncated: true, next: 2_001 })
+      expect(lines.type === "text-page" ? lines.content.split("\n") : []).toHaveLength(2_000)
+      expect(bytes).toMatchObject({ type: "text-page", truncated: true, next: 26 })
+      expect(bytes.type === "text-page" ? Buffer.byteLength(bytes.content) : Infinity).toBeLessThanOrEqual(
+        ReadToolFileSystem.MAX_READ_BYTES,
+      )
+      expect(ranges).toEqual([{ offset: 0, length: 256 * 1024 }])
+    }),
+  )
+
+  it.effect("sorts and pages directory entries", () =>
+    Effect.gen(function* () {
+      const { environment, files, directory } = yield* fixture
+      yield* files.makeDirectory(path.join(directory, "z"))
+      yield* files.makeDirectory(path.join(directory, "a"))
+      yield* files.writeFileString(path.join(directory, "b.txt"), "")
+
+      const result = yield* ReadToolFileSystem.read(environment, absolute(directory), "folder", {
+        offset: 2,
+        limit: 1,
+      })
+
+      expect(result).toMatchObject({
+        type: "list-page",
+        entries: [{ path: `z${path.sep}`, type: "directory" }],
+        truncated: true,
+        next: 3,
+      })
+    }),
+  )
+
+  it.effect("stops checking for null bytes after the requested page", () =>
+    Effect.gen(function* () {
+      const { environment, files, directory } = yield* fixture
+      const file = path.join(directory, "nul.txt")
+      yield* files.writeFile(file, Uint8Array.from([...new TextEncoder().encode("one\n"), 0]))
+
+      const result = yield* ReadToolFileSystem.read(environment, absolute(file), "nul.txt", { limit: 1 })
+
+      expect(result).toMatchObject({ type: "text-page", content: "one", truncated: true, next: 2 })
+    }),
+  )
+
+  it.effect("reads page two after fetching more than the first 256KB range", () =>
+    Effect.gen(function* () {
+      const { environment, files, directory } = yield* fixture
+      const file = path.join(directory, "large.txt")
+      yield* files.writeFileString(file, `${"a".repeat(300 * 1024)}\nsecond\n`)
+
+      const result = yield* ReadToolFileSystem.read(environment, absolute(file), "large.txt", {
+        offset: 2,
+        limit: 1,
+      })
+
+      expect(result).toMatchObject({ type: "text-page", content: "second", offset: 2, truncated: false })
     }),
   )
 
   it.effect("preserves the media ingestion limit message", () =>
     Effect.gen(function* () {
-      const { fs, files, directory } = yield* fixture
+      const { environment, files, directory } = yield* fixture
       const file = path.join(directory, "oversized.png")
       yield* files.writeFile(file, Uint8Array.of(0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a))
       yield* files.truncate(file, ReadToolFileSystem.MAX_MEDIA_INGEST_BYTES + 1)
 
-      const error = yield* ReadToolFileSystem.read(fs, file, "oversized.png").pipe(Effect.flip)
+      const error = yield* ReadToolFileSystem.read(environment, absolute(file), "oversized.png").pipe(Effect.flip)
 
       expect(error).toBeInstanceOf(ReadToolFileSystem.MediaIngestLimitError)
       expect(error.message).toBe(
@@ -150,11 +260,11 @@ describe("ReadToolFileSystem", () => {
 
   it.effect("reads PDFs as bounded media", () =>
     Effect.gen(function* () {
-      const { fs, files, directory } = yield* fixture
+      const { environment, files, directory } = yield* fixture
       const file = path.join(directory, "document.pdf")
       yield* files.writeFileString(file, "%PDF-1.7\ncontent")
 
-      const result = yield* ReadToolFileSystem.read(fs, file, "document.pdf")
+      const result = yield* ReadToolFileSystem.read(environment, absolute(file), "document.pdf")
 
       expect(result).toMatchObject({
         type: "file",

packages/core/test/tool-read.test.ts

@@ -1,6 +1,6 @@
 import { beforeEach, describe, expect } from "bun:test"
 import path from "path"
-import { Effect, Exit, Layer, PlatformError, Stream } from "effect"
+import { Effect, Exit, Layer, Stream } from "effect"
 import { Config } from "@opencode-ai/core/config"
 import { Document, Info } from "@opencode-ai/schema/config"
 import { ConfigMedia } from "@opencode-ai/schema/config/media"
@@ -21,6 +21,7 @@ import { ReadTool } from "@opencode-ai/core/tool/plugin/read"
 import { ReadToolFileSystem } from "@opencode-ai/core/tool/read-filesystem"
 import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
 import { SessionInstructions } from "@opencode-ai/core/session/instructions"
+import { Environment } from "@opencode-ai/core/environment"
 import { testEffect } from "./lib/effect"
 import { toolIdentity, executeTool, registerToolPlugin, toolDefinitions } from "./lib/tool"
 
@@ -42,24 +43,13 @@ const readToolNode = makeLocationNode({
 const assertions: Permission.AssertInput[] = []
 const missingPath = "__missing_read_target__.txt"
 const missingAbsolutePath = path.join(process.cwd(), missingPath)
-const notFound = (target: string) =>
-  PlatformError.systemError({
-    _tag: "NotFound",
-    module: "FileSystem",
-    method: "stat",
-    pathOrDescriptor: target,
-  })
 const readCalls: {
   input: AbsolutePath
   page: ReadToolFileSystem.PageInput
 }[] = []
-const listCalls: ReadToolFileSystem.PageInput[] = []
-let listResult = new ReadToolFileSystem.ListPage({ type: "list-page", entries: [], truncated: false })
-let resolvedType: "file" | "directory" = "file"
 let resolveFailure: unknown
-let inspectFailure: ReadToolFileSystem.InspectError | undefined
 let directoryEntries: string[] = []
-let readResult: ReadToolFileSystem.FileContent | ReadToolFileSystem.TextPage = {
+let readResult: ReadToolFileSystem.FileContent | ReadToolFileSystem.TextPage | ReadToolFileSystem.ListPage = {
   type: "file",
   uri: "file:///README.md",
   name: "README.md",
@@ -71,22 +61,12 @@ let readFailure: ReadToolFileSystem.ReadError | undefined
 const reader = Layer.succeed(
   ReadToolFileSystem.Service,
   ReadToolFileSystem.Service.of({
-    inspect: () =>
-      resolveFailure !== undefined
-        ? Effect.die(resolveFailure)
-        : inspectFailure !== undefined
-          ? Effect.fail(inspectFailure)
-          : Effect.succeed(resolvedType),
     read: (input, _resource, page = {}) => {
       readCalls.push({ input, page })
+      if (resolveFailure !== undefined) return Effect.die(resolveFailure)
       if (readFailure !== undefined) return Effect.fail(readFailure)
       return Effect.succeed(readResult)
     },
-    list: (_path, input = {}) =>
-      Effect.sync(() => {
-        listCalls.push(input)
-        return listResult
-      }),
   }),
 )
 let allow = true
@@ -125,17 +105,6 @@ const testFileSystem = Layer.effect(
       FSUtil.Service.of({
         ...fs,
         readDirectory: () => Effect.succeed(directoryEntries),
-        realPath: (path) =>
-          path === missingAbsolutePath
-            ? Effect.fail(
-                PlatformError.systemError({
-                  _tag: "NotFound",
-                  module: "FileSystem",
-                  method: "realPath",
-                  pathOrDescriptor: path,
-                }),
-              )
-            : Effect.succeed(path),
       }),
     ),
   ),
@@ -195,11 +164,8 @@ describe("ReadTool", () => {
   beforeEach(() => {
     assertions.length = 0
     readCalls.length = 0
-    listCalls.length = 0
     allow = true
-    resolvedType = "file"
     resolveFailure = undefined
-    inspectFailure = undefined
     directoryEntries = []
     readResult = {
       type: "file",
@@ -210,7 +176,6 @@ describe("ReadTool", () => {
       mime: "text/plain",
     }
     readFailure = undefined
-    listResult = new ReadToolFileSystem.ListPage({ type: "list-page", entries: [], truncated: false })
   })
 
   it.effect("registers, authorizes, and reads through the location filesystem", () =>
@@ -672,7 +637,7 @@ describe("ReadTool", () => {
 
   it.effect("returns missing paths as model-visible tool failures", () =>
     Effect.gen(function* () {
-      inspectFailure = notFound(missingAbsolutePath)
+      readFailure = new Environment.NotFound({ path: missingAbsolutePath })
       directoryEntries = [
         "__missing_read_target__.txt.bak",
         "copy___missing_read_target__.txt",
@@ -696,14 +661,18 @@ describe("ReadTool", () => {
         },
       })
       expect(assertions).toMatchObject([{ sessionID, action: "read", resources: [missingPath], save: ["*"] }])
-      expect(readCalls).toEqual([])
+      expect(readCalls).toEqual([
+        {
+          input: AbsolutePath.make(missingAbsolutePath),
+          page: { offset: undefined, limit: undefined },
+        },
+      ])
     }),
   )
 
   it.effect("lists a bounded directory page through read", () =>
     Effect.gen(function* () {
-      resolvedType = "directory"
-      listResult = new ReadToolFileSystem.ListPage({
+      readResult = new ReadToolFileSystem.ListPage({
         type: "list-page",
         entries: [
           FileSystem.Entry.make({ path: RelativePath.make("components/"), type: "directory" }),
@@ -726,7 +695,7 @@ describe("ReadTool", () => {
       })
       expect(result).toMatchObject({
         status: "completed",
-        output: { entries: listResult.entries, truncated: true, next: 4 },
+        output: { entries: readResult.entries, truncated: true, next: 4 },
       })
       if (result.status !== "completed") return
       expect(result.metadata).toEqual({ truncated: true })
@@ -737,14 +706,15 @@ describe("ReadTool", () => {
         },
       ])
       expect(assertions).toMatchObject([{ sessionID, action: "read", resources: ["src"], save: ["*"] }])
-      expect(listCalls).toEqual([{ offset: 2, limit: 10 }])
+      expect(readCalls).toEqual([
+        { input: AbsolutePath.make(path.join(process.cwd(), "src")), page: { offset: 2, limit: 10 } },
+      ])
     }),
   )
 
   it.effect("does not list a directory when permission is denied", () =>
     Effect.gen(function* () {
       allow = false
-      resolvedType = "directory"
       const registry = yield* Tool.Service
 
       expect(
@@ -754,7 +724,7 @@ describe("ReadTool", () => {
           call: { type: "tool-call", id: "call-read-directory-denied", name: "read", input: { path: "src" } },
         }),
       ).toEqual({ status: "error", error: { type: "permission.rejected", message: "Permission denied: read" } })
-      expect(listCalls).toEqual([])
+      expect(readCalls).toEqual([])
     }),
   )
 
@@ -773,7 +743,12 @@ describe("ReadTool", () => {
         ),
       ).toBe(true)
 
-      expect(readCalls).toEqual([])
+      expect(readCalls).toEqual([
+        {
+          input: AbsolutePath.make(path.join(process.cwd(), "missing.txt")),
+          page: { offset: undefined, limit: undefined },
+        },
+      ])
     }),
   )
 

packages/core/test/tool-search.test.ts

@@ -5,8 +5,8 @@ import { Effect, Layer } from "effect"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
 import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
+import { Environment } from "@opencode-ai/core/environment"
 import { FileSystem } from "@opencode-ai/core/filesystem"
-import { FSUtil } from "@opencode-ai/util/fs-util"
 import { Location } from "@opencode-ai/core/location"
 import { LocationMutation } from "@opencode-ai/core/location-mutation"
 import { Permission } from "@opencode-ai/core/permission"
@@ -24,19 +24,12 @@ import { executeTool, registerToolPlugin, toolIdentity } from "./lib/tool"
 const globToolNode = makeLocationNode({
   name: "test/glob-tool-plugin",
   layer: Layer.effectDiscard(registerToolPlugin(GlobTool.Plugin)),
-  deps: [
-    Tool.node,
-    FSUtil.node,
-    Ripgrep.node,
-    Location.node,
-    LocationMutation.node,
-    Permission.node,
-  ],
+  deps: [Tool.node, Environment.node, Ripgrep.node, Location.node, LocationMutation.node, Permission.node],
 })
 const grepToolNode = makeLocationNode({
   name: "test/grep-tool-plugin",
   layer: Layer.effectDiscard(registerToolPlugin(GrepTool.Plugin)),
-  deps: [Tool.node, FSUtil.node, Ripgrep.node, Location.node, LocationMutation.node, Permission.node],
+  deps: [Tool.node, Environment.node, Ripgrep.node, Location.node, LocationMutation.node, Permission.node],
 })
 const sessionID = Session.ID.make("ses_search_tool_test")
 
@@ -186,9 +179,7 @@ describe("search tools", () => {
       Effect.promise(() => tmpdir()),
       (tmp) =>
         Effect.promise(() => fs.writeFile(path.join(tmp.path, "file.txt"), "haystack\n")).pipe(
-          Effect.andThen(
-            withTools(tmp.path, (registry) => executeTool(registry, call("grep", { pattern: "needle" }))),
-          ),
+          Effect.andThen(withTools(tmp.path, (registry) => executeTool(registry, call("grep", { pattern: "needle" })))),
           Effect.tap((result) =>
             Effect.sync(() => {
               expect(result).toMatchObject({
@@ -297,9 +288,7 @@ describe("search tools", () => {
       (tmp) =>
         Effect.promise(() => fs.writeFile(path.join(tmp.path, "file.txt"), "content\n")).pipe(
           Effect.andThen(
-            withTools(tmp.path, (registry) =>
-              executeTool(registry, call("glob", { path: "file.txt", pattern: "*" })),
-            ),
+            withTools(tmp.path, (registry) => executeTool(registry, call("glob", { path: "file.txt", pattern: "*" }))),
           ),
           Effect.tap((result) =>
             Effect.sync(() => {
@@ -331,9 +320,7 @@ describe("search tools", () => {
             Effect.sync(() => {
               expect(result.status).toBe("completed")
               expect(assertions.map((input) => input.action)).toEqual(["external_directory", "glob"])
-              expect(assertions[0]?.resources).toEqual([
-                path.join(outside.path, "*").replaceAll("\\", "/"),
-              ])
+              expect(assertions[0]?.resources).toEqual([path.join(outside.path, "*").replaceAll("\\", "/")])
             }),
           ),
         )

packages/core/test/tool-shell.test.ts

@@ -524,7 +524,8 @@ describe("ShellTool", () => {
           const content = settled.content?.[0]
           if (!content || content.type !== "text") throw new Error("Expected text content")
           expect(content.text).not.toContain("one")
-          expect(content.text).toStartWith("two\nthree")
+          // Windows shells emit CRLF; the assertion targets line limits, not line endings.
+          expect(content.text.replaceAll("\r\n", "\n")).toStartWith("two\nthree")
           expect(content.text).toContain("output truncated; full output saved to:")
         })
       },

packages/core/test/tool-write.test.ts

@@ -6,7 +6,7 @@ import { FileMutation } from "@opencode-ai/core/file-mutation"
 import { Formatter } from "@opencode-ai/core/formatter"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
-import { FSUtil } from "@opencode-ai/util/fs-util"
+import { Environment } from "@opencode-ai/core/environment"
 import { Location } from "@opencode-ai/core/location"
 import { LocationMutation } from "@opencode-ai/core/location-mutation"
 import { Permission } from "@opencode-ai/core/permission"
@@ -23,7 +23,7 @@ import { toolIdentity, executeTool, registerToolPlugin, toolDefinitions } from "
 const writeToolNode = makeLocationNode({
   name: "test/write-tool-plugin",
   layer: Layer.effectDiscard(registerToolPlugin(WriteTool.Plugin)),
-  deps: [Tool.node, LocationMutation.node, FileMutation.node, Formatter.node, FSUtil.node, Permission.node],
+  deps: [Tool.node, LocationMutation.node, FileMutation.node, Environment.node, Formatter.node, Permission.node],
 })
 
 const sessionID = Session.ID.make("ses_write_tool_test")
@@ -68,17 +68,20 @@ const reset = () => {
   denyAction = undefined
 }
 
-const filesystem = Layer.effect(
-  FSUtil.Service,
+const environment = Layer.effect(
+  Environment.Service,
   Effect.gen(function* () {
-    const fs = yield* FSUtil.Service
-    return FSUtil.Service.of({
-      ...fs,
-      writeWithDirs: (target, content, mode) =>
-        Effect.sync(() => writes.push(target)).pipe(Effect.andThen(fs.writeWithDirs(target, content, mode))),
+    const current = yield* Environment.Service
+    return Environment.Service.of({
+      ...current,
+      files: {
+        ...current.files,
+        write: (target, content) =>
+          Effect.sync(() => writes.push(target)).pipe(Effect.andThen(current.files.write(target, content))),
+      },
     })
   }),
-).pipe(Layer.provide(LayerNode.compile(FSUtil.node)))
+).pipe(Layer.provide(LayerNode.compile(Environment.node)))
 
 const withTool = <A, E, R>(directory: string, body: (registry: Tool.Interface) => Effect.Effect<A, E, R>) => {
   const activeLocation = Layer.succeed(
@@ -92,7 +95,7 @@ const withTool = <A, E, R>(directory: string, body: (registry: Tool.Interface) =
       AppNodeBuilder.build(
         LayerNode.group([Tool.node, Tool.node, LocationMutation.node, FileMutation.node, writeToolNode]),
         [
-          [FSUtil.node, filesystem],
+          [Environment.node, environment],
           [Location.node, activeLocation],
           [Formatter.node, formatter],
           [Permission.node, permission],

packages/tui/src/context/storage.tsx

@@ -27,6 +27,7 @@ export interface Storage {
    * JSON-serializable.
    */
   memory<Value extends object>(key: string, options: { readonly initial: Value }): MemoryEntry<Value>
+  flush(): Promise<void>
 }
 
 function clone<Value extends object>(value: Value) {
@@ -46,6 +47,7 @@ function segment(value: string) {
 function createStorage(root: string, channel: string) {
   const entries = new Map<string, { readonly value: Entry<object>; readonly reload: () => void }>()
   const memories = new Map<string, MemoryEntry<object>>()
+  const pending = new Set<Promise<void>>()
   const directory = path.join(root, segment(channel), "tui")
   const locks = path.join(root, segment(channel), "locks")
   mkdirSync(directory, { recursive: true })
@@ -66,8 +68,8 @@ function createStorage(root: string, channel: string) {
       const [store, setStore] = createStore(load())
       const merge = (next: Value) => reconcile(next, { key: options.key })
       const reload = () => batch(() => setStore(merge(load())))
-      const update = (mutation: (draft: Value) => void) =>
-        Flock.withLock(
+      const update = (mutation: (draft: Value) => void) => {
+        const operation = Flock.withLock(
           file,
           async () => {
             const draft = load()
@@ -78,6 +80,13 @@ function createStorage(root: string, channel: string) {
           },
           { dir: locks },
         )
+        pending.add(operation)
+        operation.then(
+          () => pending.delete(operation),
+          () => pending.delete(operation),
+        )
+        return operation
+      }
       const entry = [store, update] as const
       entries.set(file, { value: entry as Entry<object>, reload })
       return entry
@@ -90,6 +99,15 @@ function createStorage(root: string, channel: string) {
       memories.set(key, entry as MemoryEntry<object>)
       return entry
     },
+    async flush() {
+      const failures: unknown[] = []
+      while (pending.size > 0) {
+        const results = await Promise.allSettled(pending)
+        failures.push(...results.filter((result) => result.status === "rejected").map((result) => result.reason))
+      }
+      if (failures.length === 1) throw failures[0]
+      if (failures.length > 1) throw new AggregateError(failures, "Storage writes failed")
+    },
   }
 
   const watcher = watch(directory, () => entries.forEach((entry) => entry.reload()))

packages/tui/src/mini/footer.form.tsx

@@ -1,6 +1,6 @@
 /** @jsxImportSource @opentui/solid */
-import { decodePasteBytes, stripAnsiSequences, type TextareaRenderable } from "@opentui/core"
-import { useKeyboard, usePaste } from "@opentui/solid"
+import type { TextareaRenderable } from "@opentui/core"
+import { useKeyboard } from "@opentui/solid"
 import { For, Show, createEffect, createMemo, createSignal, onCleanup } from "solid-js"
 import {
   createFormBodyState,
@@ -149,14 +149,6 @@ export function RunFormBody(props: {
     if (formSingle(props.request)) submit(next)
   }
 
-  usePaste((event) => {
-    const field = current()
-    if (!field || textual() || !custom() || confirm()) return
-    event.preventDefault()
-    const next = formPick(formSetSelected(state(), rows().length), props.request)
-    setState(formSetDraft(next, field, formInput(next, field) + stripAnsiSequences(decodePasteBytes(event.bytes))))
-  })
-
   const moveField = (direction: -1 | 1) => {
     const next = (state().field + direction + props.request.fields.length + 1) % (props.request.fields.length + 1)
     if (direction < 0 || confirm()) {

packages/tui/src/routes/session/form.tsx

@@ -1,7 +1,7 @@
 import { createStore } from "solid-js/store"
 import { createMemo, createSignal, For, onCleanup, onMount, Show } from "solid-js"
-import { usePaste, useRenderer, useTerminalDimensions } from "@opentui/solid"
-import { decodePasteBytes, stripAnsiSequences, type ScrollBoxRenderable, type TextareaRenderable } from "@opentui/core"
+import { useRenderer, useTerminalDimensions } from "@opentui/solid"
+import type { ScrollBoxRenderable, TextareaRenderable } from "@opentui/core"
 import open from "open"
 import { useTheme, useThemes } from "../../context/theme"
 import type { FormField, FormValue } from "@opencode-ai/client"
@@ -265,19 +265,6 @@ export function FormPrompt(props: { form: FormWithLocation }) {
     pick(row.value)
   }
 
-  usePaste((event) => {
-    if (keymap.mode.current() !== FORM_MODE) return
-    const current = answerField()
-    if (!current || textual() || !custom() || confirm()) return
-    event.preventDefault()
-    setStore("selected", rows().length)
-    setStore("custom", {
-      ...store.custom,
-      [current.key]: input() + stripAnsiSequences(decodePasteBytes(event.bytes)),
-    })
-    setStore("editing", true)
-  })
-
   function commitInput(text: string) {
     const current = answerField()
     if (!current) return false

packages/tui/src/routes/session/index.tsx

@@ -23,7 +23,7 @@ import { SplitBorder } from "../../ui/border"
 import { useTuiPaths, useTuiTerminalEnvironment } from "../../context/runtime"
 import { Spinner, SPINNER_FRAMES } from "../../component/spinner"
 import { PatchDiff } from "../../component/patch-diff"
-import { ThemeContextProvider, useTheme, useThemes } from "../../context/theme"
+import { createSyntaxStyleMemo, ThemeContextProvider, useTheme, useThemes } from "../../context/theme"
 import { BoxRenderable, ScrollBoxRenderable, addDefaultParsers, TextAttributes, RGBA } from "@opentui/core"
 import { Prompt, type PromptRef } from "../../component/prompt"
 import type {
@@ -100,6 +100,7 @@ import { withTimestampedFallback } from "@opencode-ai/util/session-title-fallbac
 import { useSessionTabs } from "../../context/session-tabs"
 import { createSingleFlight } from "../../util/single-flight"
 import type { SessionPending } from "@opencode-ai/schema/session-pending"
+import { generateThinkingSyntax } from "./thinking-syntax"
 
 addDefaultParsers(parsers.parsers)
 
@@ -1432,6 +1433,7 @@ function SessionReasoningGroupView(props: {
   const ctx = use()
   const theme = useTheme()
   const { currentSyntax: syntax } = useThemes()
+  const thinkingSyntax = createSyntaxStyleMemo(() => generateThinkingSyntax(syntax(), theme.text.subdued))
   const renderer = useRenderer()
   const [expanded, setExpanded] = createSignal(false)
   const [hover, setHover] = createSignal(false)
@@ -1527,7 +1529,7 @@ function SessionReasoningGroupView(props: {
                             filetype="markdown"
                             drawUnstyledText={false}
                             streaming={part()?.time?.completed === undefined && message()?.time.completed === undefined}
-                            syntaxStyle={syntax()}
+                            syntaxStyle={thinkingSyntax()}
                             content={content()}
                             conceal={ctx.markdownMode() === "rendered"}
                             fg={theme.text.subdued}
@@ -2060,6 +2062,7 @@ function ReasoningPart(props: {
 }) {
   const theme = useTheme()
   const { currentSyntax: syntax } = useThemes()
+  const thinkingSyntax = createSyntaxStyleMemo(() => generateThinkingSyntax(syntax(), theme.text.subdued))
   const ctx = use()
   // Collapsed by default in hide mode: a single line throughout, so the
   // layout never shifts. Click to open the full markdown block, click to close.
@@ -2112,7 +2115,7 @@ function ReasoningPart(props: {
                 filetype="markdown"
                 drawUnstyledText={false}
                 streaming={true}
-                syntaxStyle={syntax()}
+                syntaxStyle={thinkingSyntax()}
                 content={content()}
                 conceal={ctx.markdownMode() === "rendered"}
                 fg={theme.text.subdued}

packages/tui/src/routes/session/thinking-syntax.ts

@@ -0,0 +1,9 @@
+import { SyntaxStyle, type RGBA } from "@opentui/core"
+
+export function generateThinkingSyntax(syntax: SyntaxStyle, foreground: RGBA) {
+  return SyntaxStyle.fromStyles(
+    Object.fromEntries(
+      syntax.getRegisteredNames().map((name) => [name, { ...syntax.getStyle(name), fg: foreground }]),
+    ),
+  )
+}

packages/tui/test/cli/tui/dialog-open.test.tsx

@@ -1,9 +1,6 @@
 /** @jsxImportSource @opentui/solid */
 import { expect, test } from "bun:test"
 import { testRender } from "@opentui/solid"
-import { mkdtempSync, rmSync } from "fs"
-import { tmpdir } from "os"
-import path from "path"
 import { onMount } from "solid-js"
 import { DialogOpen } from "../../../src/component/dialog-open"
 import { ConfigProvider } from "../../../src/config"
@@ -14,12 +11,13 @@ import { LocationProvider, useLocation } from "../../../src/context/location"
 import { RouteProvider, useRoute } from "../../../src/context/route"
 import { TuiAppProvider } from "../../../src/context/runtime"
 import { SessionTabsProvider } from "../../../src/context/session-tabs"
-import { StorageProvider } from "../../../src/context/storage"
+import { StorageProvider, useStorage } from "../../../src/context/storage"
 import { ThemeProvider } from "../../../src/context/theme"
 import { DialogProvider, useDialog } from "../../../src/ui/dialog"
 import { ToastProvider } from "../../../src/ui/toast"
 import { createApi, createEventStream, createFetch, json, type FetchHandler } from "../../fixture/tui-client"
 import { TestTuiContexts } from "../../fixture/tui-environment"
+import { tmpdir } from "../../fixture/fixture"
 import { createTuiResolvedConfig } from "../../fixture/tui-runtime"
 
 test("selecting an unhydrated session preserves its location", async () => {
@@ -52,7 +50,7 @@ test("selecting an unhydrated session preserves its location", async () => {
     expect(fixture.route.data).toEqual({ type: "session", sessionID: "ses_remote" })
     expect(fixture.location.ref).toEqual(remote)
   } finally {
-    fixture.dispose()
+    await fixture.dispose()
   }
 })
 
@@ -94,7 +92,7 @@ test("shows the current project and opens its root", async () => {
     expect(fixture.route.data).toEqual({ type: "home", location: { directory: root } })
     expect(fixture.location.ref).toEqual({ directory: root })
   } finally {
-    fixture.dispose()
+    await fixture.dispose()
   }
 })
 
@@ -149,7 +147,7 @@ test("preserves a moved project when sessions arrive", async () => {
 
     expect(fixture.route.data).toEqual({ type: "home", location: { directory: "/tmp/opencode/second" } })
   } finally {
-    fixture.dispose()
+    await fixture.dispose()
   }
 })
 
@@ -160,18 +158,21 @@ async function renderOpen(
     location: ReturnType<typeof useLocation>
   }) => void | Promise<void>,
 ) {
-  const state = mkdtempSync(path.join(tmpdir(), "opencode-dialog-open-"))
+  const temporary = await tmpdir()
+  const state = temporary.path
   const events = createEventStream()
   const calls = createFetch(handler, events)
   let route!: ReturnType<typeof useRoute>
   let location!: ReturnType<typeof useLocation>
   let data!: ReturnType<typeof useData>
+  let storage!: ReturnType<typeof useStorage>
 
   function Probe() {
     const dialog = useDialog()
     route = useRoute()
     location = useLocation()
     data = useData()
+    storage = useStorage()
     onMount(
       () => void Promise.resolve(beforeOpen?.({ data, location })).then(() => dialog.replace(() => <DialogOpen />)),
     )
@@ -223,9 +224,10 @@ async function renderOpen(
     get data() {
       return data
     },
-    dispose() {
+    async dispose() {
       app.renderer.destroy()
-      rmSync(state, { recursive: true, force: true })
+      await storage.flush()
+      await temporary[Symbol.asyncDispose]()
     },
   }
 }

packages/tui/test/cli/tui/form.test.tsx

@@ -15,7 +15,7 @@ import { TestTuiContexts } from "../../fixture/tui-environment"
 import { createTuiResolvedConfig } from "../../fixture/tui-runtime"
 import { createApi, createEventStream, createFetch } from "../../fixture/tui-client"
 
-async function mountForm(root: string, width = 80, fields?: FormWithLocation["fields"]) {
+async function mountForm(root: string, width = 80) {
   const state = path.join(root, "state")
   await mkdir(state, { recursive: true })
 
@@ -37,7 +37,7 @@ async function mountForm(root: string, width = 80, fields?: FormWithLocation["fi
     id: "frm_test",
     sessionID: "ses_test",
     title: "Authorization required",
-    fields: fields ?? [
+    fields: [
       {
         key: "authorization",
         type: "external",
@@ -126,57 +126,3 @@ test("includes external acknowledgements in progress", async () => {
     prompt.app.renderer.destroy()
   }
 })
-
-test("pasting on a custom choice opens its editor without submitting", async () => {
-  await using tmp = await tmpdir()
-  const prompt = await mountForm(tmp.path, 80, [
-    {
-      key: "target",
-      type: "string",
-      options: [{ value: "staging", label: "Staging" }],
-      custom: true,
-    },
-  ])
-  try {
-    await prompt.app.mockInput.pasteBracketedText("production\nwest")
-    await prompt.app.waitFor(() => prompt.app.renderer.currentFocusedEditor?.plainText === "production\nwest")
-
-    expect(prompt.app.captureCharFrame()).toContain("Type your own answer")
-    expect(prompt.replies).toEqual([])
-  } finally {
-    prompt.app.renderer.destroy()
-  }
-})
-
-test("text fields retain default paste behavior", async () => {
-  await using tmp = await tmpdir()
-  const prompt = await mountForm(tmp.path, 80, [{ key: "notes", type: "string" }])
-  try {
-    await prompt.app.mockInput.pasteBracketedText("normal paste")
-
-    expect(prompt.app.renderer.currentFocusedEditor?.plainText).toBe("normal paste")
-    expect(prompt.replies).toEqual([])
-  } finally {
-    prompt.app.renderer.destroy()
-  }
-})
-
-test("pasting on a choice without custom answers does not open an editor", async () => {
-  await using tmp = await tmpdir()
-  const prompt = await mountForm(tmp.path, 80, [
-    {
-      key: "target",
-      type: "string",
-      options: [{ value: "staging", label: "Staging" }],
-    },
-  ])
-  try {
-    await prompt.app.mockInput.pasteBracketedText("production")
-
-    expect(prompt.app.renderer.currentFocusedEditor).toBeNull()
-    expect(prompt.app.captureCharFrame()).not.toContain("production")
-    expect(prompt.replies).toEqual([])
-  } finally {
-    prompt.app.renderer.destroy()
-  }
-})

packages/tui/test/context/session-tabs.test.tsx

@@ -1,9 +1,8 @@
 /** @jsxImportSource @opentui/solid */
-import { afterAll, expect, test } from "bun:test"
+import { expect, test } from "bun:test"
 import type { OpenCodeEvent } from "@opencode-ai/client"
 import { testRender } from "@opentui/solid"
-import { mkdirSync, mkdtempSync, readdirSync, rmSync, watch } from "fs"
-import { tmpdir } from "os"
+import { mkdirSync, watch } from "fs"
 import path from "path"
 import { ConfigProvider } from "../../src/config"
 import { ClientProvider, useClient } from "../../src/context/client"
@@ -12,9 +11,10 @@ import { RouteProvider, useRoute } from "../../src/context/route"
 import { TuiAppProvider } from "../../src/context/runtime"
 import { SessionTabsProvider, useSessionTabs } from "../../src/context/session-tabs"
 import { NEW_SESSION_TAB_TITLE } from "../../src/context/session-tabs-model"
-import { StorageProvider } from "../../src/context/storage"
+import { StorageProvider, useStorage } from "../../src/context/storage"
 import { createApi, createEventStream, createFetch, directory, json } from "../fixture/tui-client"
 import { TestTuiContexts } from "../fixture/tui-environment"
+import { tmpdir } from "../fixture/fixture"
 import { createTuiResolvedConfig } from "../fixture/tui-runtime"
 
 async function wait(fn: () => boolean | Promise<boolean>, timeout = 2_000) {
@@ -25,35 +25,12 @@ async function wait(fn: () => boolean | Promise<boolean>, timeout = 2_000) {
   }
 }
 
-// State directories are removed after the whole suite instead of per test: persistence writes are
-// fire-and-forget behind a file lock, so a teardown-time removal races any still-queued write.
-const stateDirs: string[] = []
-
-afterAll(async () => {
-  for (const dir of stateDirs) {
-    // Drain any lock still held by a late write before deleting the tree beneath it.
-    await wait(() => {
-      try {
-        return readdirSync(path.join(dir, "test", "locks")).length === 0
-      } catch {
-        return true
-      }
-    }).catch(() => undefined)
-    rmSync(dir, { recursive: true, force: true })
-  }
-})
-
-function stateDir(prefix: string) {
-  const dir = mkdtempSync(path.join(tmpdir(), prefix))
-  stateDirs.push(dir)
-  return dir
-}
-
 async function renderSessionTabs(
   initialSessionID: string,
   options?: { state?: string; title?: string; home?: boolean; persisted?: string[]; sessionGate?: Promise<void> },
 ) {
-  const state = options?.state ?? stateDir("opencode-session-tabs-")
+  const temporary = options?.state ? undefined : await tmpdir()
+  const state = options?.state ?? temporary!.path
   if (options?.persisted) {
     const file = path.join(state, "test", "tui", "tabs.json")
     mkdirSync(path.dirname(file), { recursive: true })
@@ -88,12 +65,14 @@ async function renderSessionTabs(
   let route!: ReturnType<typeof useRoute>
   let client!: ReturnType<typeof useClient>
   let data!: ReturnType<typeof useData>
+  let storage!: ReturnType<typeof useStorage>
 
   function Probe() {
     tabs = useSessionTabs()
     route = useRoute()
     client = useClient()
     data = useData()
+    storage = useStorage()
     return <box />
   }
 
@@ -127,8 +106,10 @@ async function renderSessionTabs(
     sessions,
     state,
     emit: (event: OpenCodeEvent) => events.emit({ ...event, location: { directory } }),
-    destroy() {
+    async destroy() {
       app.renderer.destroy()
+      await storage.flush()
+      await temporary?.[Symbol.asyncDispose]()
     },
   }
 }
@@ -149,7 +130,7 @@ test("loads persisted tab metadata concurrently on connect", async () => {
     await wait(() => setup.data.session.get("first") !== undefined && setup.data.session.get("second") !== undefined)
   } finally {
     release()
-    setup.destroy()
+    await setup.destroy()
   }
 })
 
@@ -159,17 +140,19 @@ test("stores session tabs for the current working directory by default", async (
   try {
     const file = path.join(setup.state, "test", "tui", "tabs.json")
     await wait(() => Bun.file(file).size > 0)
-    expect(await Bun.file(file).json()).toEqual({
-      global: { tabs: [], unread: {} },
-      cwd: { [directory]: { tabs: [{ sessionID: "first" }], unread: {} } },
-    })
+    const stored = await Bun.file(file).json()
+    expect(stored.global).toEqual({ tabs: [], unread: {} })
+    expect(Object.keys(stored.cwd)).toEqual([directory])
+    expect(stored.cwd[directory].tabs.map((tab: { sessionID: string }) => tab.sessionID)).toEqual(["first"])
+    expect(stored.cwd[directory].unread).toEqual({})
   } finally {
-    setup.destroy()
+    await setup.destroy()
   }
 })
 
 test("concurrent TUIs do not alternate shared tab titles from divergent session caches", async () => {
-  const state = stateDir("opencode-session-tabs-shared-")
+  await using temporary = await tmpdir()
+  const state = temporary.path
   let titled: Awaited<ReturnType<typeof renderSessionTabs>> | undefined
   let untitled: Awaited<ReturnType<typeof renderSessionTabs>> | undefined
 
@@ -206,8 +189,8 @@ test("concurrent TUIs do not alternate shared tab titles from divergent session
 
     expect(observed).toEqual(["Generated title"])
   } finally {
-    titled?.destroy()
-    untitled?.destroy()
+    if (titled) await titled.destroy()
+    if (untitled) await untitled.destroy()
   }
 })
 
@@ -255,7 +238,7 @@ test("user prompt admissions pulse an already-busy background tab", async () =>
     expect(setup.tabs.status("active").promptPulse).toBe(0)
     expect(setup.tabs.status("background")).toMatchObject({ promptPulse: 2, busy: true })
   } finally {
-    setup.destroy()
+    await setup.destroy()
   }
 })
 
@@ -286,6 +269,6 @@ test("tracks a temporary new session tab across close and creation", async () =>
     expect(setup.tabs.newTab()).toBe(false)
     expect(setup.tabs.tabs().find((tab) => tab.sessionID === "third")?.title).toBe(NEW_SESSION_TAB_TITLE)
   } finally {
-    setup.destroy()
+    await setup.destroy()
   }
 })

packages/tui/test/mini/footer.view.test.tsx

@@ -277,41 +277,6 @@ test("direct footer preserves a partial multi-field form draft across permission
   }
 })
 
-test("direct footer paste opens a custom choice editor without submitting", async () => {
-  const replies: unknown[] = []
-  const app = await renderFooter({
-    height: 12,
-    view: {
-      type: "form",
-      request: {
-        id: "frm_custom_paste",
-        sessionID: "ses_child",
-        title: "Deployment target",
-        fields: [
-          {
-            key: "target",
-            type: "string",
-            options: [{ value: "staging", label: "Staging" }],
-            custom: true,
-          },
-        ],
-      },
-    },
-    onFormReply: (reply) => replies.push(reply),
-  })
-
-  try {
-    await app.renderOnce()
-    await app.mockInput.pasteBracketedText("production\nwest")
-    await app.renderOnce()
-
-    expect(app.renderer.currentFocusedEditor?.plainText).toBe("production\nwest")
-    expect(replies).toEqual([])
-  } finally {
-    app.cleanup()
-  }
-})
-
 function expectPaletteList(list: BoxRenderable, selectedIndex: number) {
   expect(list.backgroundColor.toInts()).toEqual((RUN_THEME_FALLBACK.footer.shade as RGBA).toInts())
   expect((list.getChildren()[selectedIndex] as BoxRenderable).backgroundColor.toInts()).toEqual(

packages/util/src/bom.ts

@@ -20,17 +20,25 @@ export function has(content: Uint8Array) {
   return content[0] === 0xef && content[1] === 0xbb && content[2] === 0xbf
 }
 
+export function decodeBytes(content: Uint8Array) {
+  return split(decode(content))
+}
+
+export function syncBytes(content: Uint8Array, bom: boolean) {
+  const decoded = decode(content)
+  const current = split(decoded)
+  const canonical = join(current.text, bom)
+  return { text: current.text, bytes: decoded === canonical ? undefined : new TextEncoder().encode(canonical) }
+}
+
 export const readFile = Effect.fn("Bom.readFile")(function* (fs: FSUtil.Interface, filepath: string) {
-  return split(decode(yield* fs.readFile(filepath)))
+  return decodeBytes(yield* fs.readFile(filepath))
 })
 
 export const syncFile = Effect.fn("Bom.syncFile")(function* (fs: FSUtil.Interface, filepath: string, bom: boolean) {
-  const decoded = decode(yield* fs.readFile(filepath))
-  const current = split(decoded)
-  const canonical = join(current.text, bom)
-  if (decoded === canonical) return current.text
-  yield* fs.writeWithDirs(filepath, canonical)
-  return current.text
+  const synced = syncBytes(yield* fs.readFile(filepath), bom)
+  if (synced.bytes) yield* fs.writeWithDirs(filepath, synced.bytes)
+  return synced.text
 })
 
 function decode(content: Uint8Array) {