refactor(util): drop redundant resolved node names

.github/workflows/deploy.yml

@@ -5,7 +5,6 @@ on:
     branches:
       - dev
       - production
-      - beta
   workflow_dispatch:
 
 concurrency: ${{ github.workflow }}-${{ github.ref }}
@@ -16,7 +15,7 @@ permissions:
 
 jobs:
   deploy:
-    if: github.repository == 'anomalyco/opencode' && (github.ref_name == 'dev' || github.ref_name == 'production' || github.ref_name == 'beta')
+    if: github.repository == 'anomalyco/opencode' && (github.ref_name == 'dev' || github.ref_name == 'production')
     runs-on: ubuntu-latest
     environment: ${{ github.ref_name }}
     steps:
@@ -29,7 +28,6 @@ jobs:
           node-version: "24"
 
       - uses: aws-actions/configure-aws-credentials@7474bc4690e29a8392af63c5b98e7449536d5c3a # v4.3.1
-        if: github.ref_name != 'beta'
         with:
           role-to-assume: ${{ vars.AWS_DEPLOY_ROLE_ARN }}
           role-session-name: opencode-${{ github.run_id }}

infra/app.ts

@@ -1,5 +1,4 @@
 import { domain } from "./stage"
-import { createWebApp } from "./webapp"
 
 const GITHUB_APP_ID = new sst.Secret("GITHUB_APP_ID")
 const GITHUB_APP_PRIVATE_KEY = new sst.Secret("GITHUB_APP_PRIVATE_KEY")
@@ -60,4 +59,12 @@ new sst.cloudflare.x.Astro("Web", {
   },
 })
 
-createWebApp("app." + domain)
+new sst.cloudflare.StaticSite("WebApp", {
+  domain: "app." + domain,
+  path: "packages/app",
+  build: {
+    // Preserve Sentry credentials and run source-map uploads on every deployment.
+    command: "bun run build",
+    output: "./dist",
+  },
+})

infra/webapp.ts

@@ -1,18 +0,0 @@
-export function createWebApp(domain: string) {
-  return new sst.cloudflare.StaticSite("WebApp", {
-    domain,
-    path: "packages/app",
-    environment:
-      $app.stage === "beta"
-        ? {
-            OPENCODE_CHANNEL: "beta",
-            VITE_SENTRY_ENVIRONMENT: "beta",
-          }
-        : undefined,
-    build: {
-      // Preserve Sentry credentials and run source-map uploads on every deployment.
-      command: "bun run build",
-      output: "./dist",
-    },
-  })
-}

packages/app/README.md

@@ -71,25 +71,4 @@ Environment options:
 
 ## Deployment
 
-The `deploy` GitHub Actions workflow uses SST to deploy the web app from these branches in `anomalyco/opencode`:
-
-| Branch       | Site                  |
-| ------------ | --------------------- |
-| `dev`        | `app.dev.opencode.ai` |
-| `production` | `app.opencode.ai`     |
-| `beta`       | `beta.opencode.ai`    |
-
-Changes merged into `v2` reach the beta site when they are promoted to `beta`. The beta SST stage deploys
-only the web app, using the same `WebApp` StaticSite definition as production. It sets the build channel
-and Sentry environment to `beta` without deploying the API, console, database, or billing infrastructure.
-
-The hosted app defaults to `http://localhost:49374`, matching the managed V2 service. Saved server selections
-override this default. Connecting still requires the service's credentials.
-
-The workflow reuses the repository's `CLOUDFLARE_API_TOKEN` and web Sentry settings. The Cloudflare token
-must cover SST's R2 state storage, KV assets, Workers, and custom-domain management in the account that
-owns `opencode.ai`. The beta GitHub environment must allow deployments from the `beta` branch; it does not
-need AWS credentials.
-
-SST manages the beta site's custom domain. The first deployment creates its DNS record and TLS certificate.
-Do not create a CNAME for `beta.opencode.ai` first, because it would conflict with the Workers custom domain.
+You can deploy the `dist` folder to any static host provider (netlify, surge, now, etc.)

packages/app/src/runtime/platform/web.ts

@@ -53,7 +53,7 @@ export function createWebPlatform(version: string) {
 }
 
 function getCurrentServerUrl() {
-  if (location.hostname.includes("opencode.ai")) return "http://localhost:49374"
+  if (location.hostname.includes("opencode.ai")) return "http://localhost:4096"
   if (import.meta.env.DEV)
     return `http://${import.meta.env.VITE_OPENCODE_SERVER_HOST ?? "localhost"}:${import.meta.env.VITE_OPENCODE_SERVER_PORT ?? "4096"}`
   return location.origin

packages/app/src/shell/shell.tsx

@@ -43,12 +43,12 @@ export default function Layout(props: ParentProps) {
         style={{
           "padding-top": "env(safe-area-inset-top, 0px)",
           "padding-bottom": "env(safe-area-inset-bottom, 0px)",
-          // Native Windows chrome supplies the gap; retain paint clearance for the panels' outer outlines.
+          // The native Windows titlebar already includes the gap above the content panels.
           "--shell-top-inset":
             platform.platform === "desktop" &&
             platform.os === "windows" &&
             !(mobile() && preferences.general.mobileTitlebarPosition() === "bottom")
-              ? "1px"
+              ? "0px"
               : "8px",
         }}
       >

packages/cli/src/commands/commands.ts

@@ -1,7 +1,6 @@
 import { Argument, Flag, GlobalFlag } from "effect/unstable/cli"
 import { Schema } from "effect"
 import { Spec } from "../framework/spec"
-import { Updater } from "../services/updater"
 
 export const PrintLogs = GlobalFlag.setting("print-logs")({
   flag: Flag.boolean("print-logs").pipe(
@@ -57,20 +56,6 @@ const Root = Spec.make(typeof OPENCODE_CLI_NAME === "string" ? OPENCODE_CLI_NAME
     prompt: Flag.string("prompt").pipe(Flag.withDescription("Prompt to use"), Flag.optional),
   },
   commands: [
-    Spec.make("upgrade", {
-      description: "Upgrade OpenCode to the latest or a specific version",
-      params: {
-        target: Argument.string("target").pipe(
-          Argument.withDescription("Version to upgrade to (with or without a leading v)"),
-          Argument.optional,
-        ),
-        method: Flag.choice("method", Updater.methods).pipe(
-          Flag.withAlias("m"),
-          Flag.withDescription("Installation method to use"),
-          Flag.optional,
-        ),
-      },
-    }),
     Spec.make("acp", { description: "Start an Agent Client Protocol server" }),
     Spec.make("api", {
       description: "Make a request to the running server",

packages/cli/src/commands/handlers/upgrade.ts

@@ -1,38 +0,0 @@
-import { intro, log, outro, spinner } from "@clack/prompts"
-import { Effect, Option } from "effect"
-import { Commands } from "../commands"
-import { Runtime } from "../../framework/runtime"
-import { Updater } from "../../services/updater"
-import { handlePromptErrors } from "../../ui/prompt"
-import { OPENCODE_VERSION } from "../../version"
-
-export default Runtime.handler(
-  Commands.commands.upgrade,
-  Effect.fn("cli.upgrade")(function* (input) {
-    intro("Upgrade")
-    const updater = yield* Updater.Service
-    const method = Option.getOrUndefined(input.method) ?? (yield* updater.method())
-    if (!method)
-      return yield* Effect.fail(
-        new Error("Could not detect the installation method. Pass --method to choose how to upgrade OpenCode."),
-      )
-
-    log.info(`Using method: ${method}`)
-    const target = Option.getOrUndefined(input.target) ?? (yield* updater.latest())
-    const version = target.trim().replace(/^v/, "")
-    if (version === OPENCODE_VERSION) {
-      log.warn(`OpenCode upgrade skipped: ${version} is already installed`)
-      outro("Done")
-      return
-    }
-
-    log.info(`From ${OPENCODE_VERSION} → ${version}`)
-    const progress = spinner()
-    progress.start("Upgrading...")
-    yield* updater.upgrade(method, target).pipe(
-      Effect.tap(() => Effect.sync(() => progress.stop("Upgrade complete"))),
-      Effect.tapCause(() => Effect.sync(() => progress.stop("Upgrade failed", 1))),
-    )
-    outro("Done")
-  }, handlePromptErrors),
-)

packages/cli/src/index.ts

@@ -17,7 +17,6 @@ import { CpuProfile } from "./cpu-profile"
 
 const Handlers = Runtime.handlers(Commands, {
   $: () => import("./commands/handlers/default"),
-  upgrade: () => import("./commands/handlers/upgrade"),
   acp: () => import("./commands/handlers/acp"),
   api: () => import("./commands/handlers/api"),
   auth: {
@@ -99,12 +98,13 @@ Effect.gen(function* () {
   Effect.provide(Config.layer),
   Effect.provide(Updater.layer),
   Effect.provide(
-    LayerNode.compile(LayerNode.group([Global.node, AppProcess.node, Npm.node]), [
-      [
-        Global.node,
-        Global.layerWith(process.env.OPENCODE_CONFIG_DIR ? { config: process.env.OPENCODE_CONFIG_DIR } : {}),
+    LayerNode.compile(LayerNode.group([Global.node, AppProcess.node, Npm.node]), {
+      replacements: [
+        Global.node.replace(
+          Global.layerWith(process.env.OPENCODE_CONFIG_DIR ? { config: process.env.OPENCODE_CONFIG_DIR } : {}),
+        ),
       ],
-    ]),
+    }),
   ),
   Effect.provide(
     Observability.layer({

packages/cli/src/server-process.ts

@@ -30,12 +30,13 @@ export const run = Effect.fnUntraced(function* (options: Options) {
   return yield* processEffect(options).pipe(
     Effect.provide(Updater.layer),
     Effect.provide(
-      LayerNode.compile(LayerNode.group([Global.node, AppProcess.node]), [
-        [
-          Global.node,
-          Global.layerWith(process.env.OPENCODE_CONFIG_DIR ? { config: process.env.OPENCODE_CONFIG_DIR } : {}),
+      LayerNode.compile(LayerNode.group([Global.node, AppProcess.node]), {
+        replacements: [
+          Global.node.replace(
+            Global.layerWith(process.env.OPENCODE_CONFIG_DIR ? { config: process.env.OPENCODE_CONFIG_DIR } : {}),
+          ),
         ],
-      ]),
+      }),
     ),
     Effect.provide(NodeServices.layer),
   )

packages/cli/src/services/updater-action.ts

@@ -15,7 +15,7 @@ export function action(current: string, latest: string, policy: Policy): Action
   return policy === "notify" ? "notify" : "upgrade"
 }
 
-export function parseReleaseVersion(input: string) {
+function parseReleaseVersion(input: string) {
   if (input.length > 256) return
   const match = input.trim().match(versionPattern)
   if (!match) return

packages/cli/src/services/updater.ts

@@ -5,21 +5,19 @@ import { Context, Duration, Effect, FileSystem, Layer } from "effect"
 import { ChildProcess } from "effect/unstable/process"
 import { parse, type ParseError } from "jsonc-parser"
 import path from "node:path"
-import { action, parseReleaseVersion, type Policy } from "./updater-action"
+import { action, type Policy } from "./updater-action"
 
 declare const OPENCODE_CLI_NAME: string | undefined
 
-export const methods = ["curl", "npm", "pnpm", "bun", "yarn"] as const
-export type Method = (typeof methods)[number]
+type Method = "npm" | "pnpm" | "bun" | "yarn" | "curl"
 
 const packageName =
-  typeof OPENCODE_CLI_NAME === "string" && OPENCODE_CLI_NAME === "opencode2-node" ? "opencode-node" : "@opencode-ai/cli"
+  typeof OPENCODE_CLI_NAME === "string" && OPENCODE_CLI_NAME === "opencode2-node"
+    ? OPENCODE_CLI_NAME
+    : "@opencode-ai/cli"
 
 export interface Interface {
   readonly check: () => Effect.Effect<void>
-  readonly method: () => Effect.Effect<Method | undefined>
-  readonly latest: () => Effect.Effect<string, Error>
-  readonly upgrade: (method: Method, version: string) => Effect.Effect<void, Error>
 }
 
 export class Service extends Context.Service<Service, Interface>()("@opencode/cli/Updater") {}
@@ -112,9 +110,7 @@ export const layer = Layer.effect(
       return data.version
     })
 
-    const upgrade = Effect.fnUntraced(function* (method: Method, input: string) {
-      if (!parseReleaseVersion(input)) return yield* Effect.fail(new Error(`Invalid version: ${input}`))
-      const version = input.trim().replace(/^v/, "")
+    const upgrade = Effect.fnUntraced(function* (method: Method, version: string) {
       const target = `${packageName}@${version}`
       const commands: Record<Exclude<Method, "bun" | "curl">, string[]> = {
         npm: ["npm", "install", "--global", target],
@@ -142,7 +138,7 @@ export const layer = Layer.effect(
           }
           return yield* run(commands[method], "5 minutes")
         }),
-      ).pipe(Effect.mapError((cause) => new Error(`Failed to update with ${method}`, { cause })))
+      )
       if (result.code === 0) return
       return yield* Effect.fail(new Error(result.stderr.trim() || `Failed to update with ${method}`))
     })
@@ -177,7 +173,7 @@ export const layer = Layer.effect(
       Effect.catchCause((cause) => Effect.logWarning("automatic update failed", { cause })),
     )
 
-    return Service.of({ check, method, latest, upgrade })
+    return Service.of({ check })
   }),
 )
 

packages/cli/test/fixture/upgrade.ts

@@ -1,36 +0,0 @@
-import { NodeServices } from "@effect/platform-node"
-import { Effect } from "effect"
-import { Command } from "effect/unstable/cli"
-import { Commands } from "../../src/commands/commands"
-import upgrade from "../../src/commands/handlers/upgrade"
-import { Updater } from "../../src/services/updater"
-
-const record = (event: unknown) => console.log(`EVENT ${JSON.stringify(event)}`)
-
-await Effect.runPromise(
-  Command.runWith(Commands.commands.upgrade.spec.pipe(Command.withHandler(upgrade)), { version: "test" })(
-    process.argv.slice(2),
-  ).pipe(
-    Effect.provideService(Updater.Service, {
-      check: () => Effect.die("Manual upgrades must not run the automatic update check"),
-      method: () =>
-        Effect.sync(() => {
-          record("method")
-          return Updater.methods.find((method) => method === (process.env.UPGRADE_TEST_METHOD ?? "npm"))
-        }),
-      latest: () =>
-        Effect.suspend(() => {
-          record("latest")
-          return process.env.UPGRADE_TEST_LATEST_ERROR
-            ? Effect.fail(new Error("Update check failed"))
-            : Effect.succeed("0.0.0-beta-new")
-        }),
-      upgrade: (method, version) =>
-        Effect.suspend(() => {
-          record({ method, version })
-          return process.env.UPGRADE_TEST_INSTALL_ERROR ? Effect.fail(new Error("Permission denied")) : Effect.void
-        }),
-    }),
-    Effect.provide(NodeServices.layer),
-  ),
-)

packages/cli/test/updater-install.test.ts

@@ -1,227 +0,0 @@
-import { NodeServices } from "@effect/platform-node"
-import { Global } from "@opencode-ai/util/global"
-import { AppProcess } from "@opencode-ai/util/process"
-import { expect, test } from "bun:test"
-import { Effect, FileSystem, Stream } from "effect"
-import { ChildProcess, ChildProcessSpawner } from "effect/unstable/process"
-import { existsSync } from "node:fs"
-import path from "node:path"
-import { Updater } from "../src/services/updater"
-import { testEffect } from "../../core/test/lib/effect"
-
-const it = testEffect(NodeServices.layer)
-
-declare const OPENCODE_CLI_NAME: string | undefined
-
-function fixture(
-  respond: (command: ChildProcess.StandardCommand) => Partial<AppProcess.RunResult> & {
-    error?: AppProcess.AppProcessError
-  } = () => ({}),
-) {
-  return Effect.gen(function* () {
-    const fs = yield* FileSystem.FileSystem
-    const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
-    const root = yield* fs.makeTempDirectoryScoped({ prefix: "opencode-updater-" })
-    const global = Global.make({
-      home: path.join(root, "home"),
-      data: path.join(root, "data"),
-      cache: path.join(root, "cache"),
-      config: path.join(root, "config"),
-      state: path.join(root, "state"),
-      tmp: path.join(root, "tmp"),
-      bin: path.join(root, "bin"),
-      log: path.join(root, "log"),
-      repos: path.join(root, "repos"),
-    })
-    const commands: string[][] = []
-    const updater = yield* Updater.Service.pipe(
-      Effect.provide(Updater.layer),
-      Effect.provideService(Global.Service, global),
-      Effect.provideService(
-        AppProcess.Service,
-        AppProcess.Service.of({
-          ...spawner,
-          run: (command) =>
-            Effect.suspend(() => {
-              if (command._tag !== "StandardCommand") return Effect.die("Unexpected piped install command")
-              commands.push([command.command, ...command.args])
-              const result = respond(command)
-              if (result.error) return Effect.fail(result.error)
-              return Effect.succeed({
-                command: command.command,
-                exitCode: 0,
-                stdout: Buffer.alloc(0),
-                stderr: Buffer.alloc(0),
-                stdoutTruncated: false,
-                stderrTruncated: false,
-                ...result,
-              })
-            }),
-          runStream: () => Stream.die("Unexpected streaming install command"),
-        }),
-      ),
-    )
-    return { updater, commands, global, fs }
-  })
-}
-
-const installs = [
-  { method: "npm", command: ["npm", "install", "--global", "@opencode-ai/cli@2.3.4-beta.1"] },
-  {
-    method: "pnpm",
-    command: ["pnpm", "add", "--global", "--allow-build=@opencode-ai/cli", "@opencode-ai/cli@2.3.4-beta.1"],
-  },
-  { method: "yarn", command: ["yarn", "global", "add", "@opencode-ai/cli@2.3.4-beta.1"] },
-] as const
-
-installs.forEach(({ method, command }) => {
-  it.live(`${method} installs the explicit V2 package version without a leading v`, () =>
-    Effect.gen(function* () {
-      const test = yield* fixture()
-      yield* test.updater.upgrade(method, "v2.3.4-beta.1")
-      expect(test.commands).toEqual([[...command]])
-    }),
-  )
-})
-;[0, 1].forEach((exitCode) => {
-  it.live(`bun isolates and removes its install cache after exit ${exitCode}`, () =>
-    Effect.gen(function* () {
-      const test = yield* fixture((command) => {
-        expect(command.command).toBe("bun")
-        expect(existsSync(command.args[4])).toBe(true)
-        return { exitCode, stderr: Buffer.from("bun install failed") }
-      })
-      const result = yield* test.updater.upgrade("bun", "v2.3.4-beta.1").pipe(Effect.flip, Effect.option)
-      const cache = test.commands[0]?.[5]
-      expect(cache).toStartWith(path.join(test.global.cache, "update-"))
-      expect(test.commands).toEqual([
-        ["bun", "install", "--global", "--trust", "--cache-dir", cache, "@opencode-ai/cli@2.3.4-beta.1"],
-      ])
-      expect(yield* test.fs.readDirectory(test.global.cache)).toEqual([])
-      expect(result._tag).toBe(exitCode === 0 ? "None" : "Some")
-      if (result._tag === "Some") expect(result.value.message).toBe("bun install failed")
-    }),
-  )
-})
-;["success", "download", "install"].forEach((failure) => {
-  it.live(`curl uses the V2 installer and cleans its directory: ${failure}`, () =>
-    Effect.gen(function* () {
-      const test = yield* fixture((command) => {
-        const installer = command.command === "curl" ? command.args[2] : command.args[0]
-        expect(existsSync(path.dirname(installer))).toBe(true)
-        return {
-          exitCode: command.command === (failure === "download" ? "curl" : failure === "install" ? "bash" : "") ? 1 : 0,
-          stderr: Buffer.from(`${failure} failed`),
-        }
-      })
-      const result = yield* test.updater.upgrade("curl", "v2.3.4-beta.1").pipe(Effect.flip, Effect.option)
-      const installer = test.commands[0]?.[3]
-      expect(installer).toStartWith(path.join(test.global.cache, "update-"))
-      expect(test.commands).toEqual([
-        ["curl", "-fsSL", "-o", installer, "https://opencode.ai/v2/install"],
-        ...(failure === "download" ? [] : [["bash", installer, "--version", "2.3.4-beta.1", "--no-modify-path"]]),
-      ])
-      expect(yield* test.fs.readDirectory(test.global.cache)).toEqual([])
-      expect(result._tag).toBe(failure === "success" ? "None" : "Some")
-      if (result._tag === "Some") expect(result.value.message).toBe(`${failure} failed`)
-    }),
-  )
-})
-
-it.live("invalid version targets never execute a command or create a cache", () =>
-  Effect.gen(function* () {
-    const test = yield* fixture()
-    yield* Effect.forEach(Updater.methods, (method) =>
-      Effect.forEach(
-        ["", "latest", "2.3", "01.2.3", "vv2.3.4", "2.3.4; echo unsafe", "--global", "v2.3.4\n--force"],
-        (version) =>
-          Effect.gen(function* () {
-            const error = yield* test.updater.upgrade(method, version).pipe(Effect.flip)
-            expect(error.message).toBe(`Invalid version: ${version}`)
-          }),
-      ),
-    )
-    expect(test.commands).toEqual([])
-    expect(yield* test.fs.exists(test.global.cache)).toBe(false)
-  }),
-)
-
-it.live("install failures expose stderr and process errors do not report success", () =>
-  Effect.gen(function* () {
-    const failed = yield* fixture(() => ({ exitCode: 1, stderr: Buffer.from("  registry denied access\n") }))
-    const error = yield* failed.updater.upgrade("npm", "2.3.4").pipe(Effect.flip)
-    expect(error.message).toBe("registry denied access")
-    const missing = yield* fixture(() => ({ error: new AppProcess.AppProcessError({ command: "npm" }) }))
-    const unavailable = yield* missing.updater.upgrade("npm", "2.3.4").pipe(Effect.flip)
-    expect(unavailable.message).toBe("Failed to update with npm")
-    expect(failed.commands).toHaveLength(1)
-    expect(missing.commands).toHaveLength(1)
-  }),
-)
-;(["npm", "pnpm", "bun", "yarn", undefined] as const).forEach((method) => {
-  it.live(`method detection identifies ${method ?? "an unknown installation"} using the V2 package`, () =>
-    Effect.gen(function* () {
-      const test = yield* fixture((command) => ({
-        stdout: Buffer.from(command.command === method ? "@opencode-ai/cli@2.3.4" : "opencode-ai@1.0.0"),
-      }))
-      expect(yield* test.updater.method()).toBe(method)
-      expect(test.commands).toEqual([
-        ["npm", "list", "-g", "--depth=0", "@opencode-ai/cli"],
-        ["pnpm", "list", "-g", "--depth=0", "@opencode-ai/cli"],
-        ["bun", "pm", "ls", "-g"],
-        ["yarn", "global", "list"],
-      ])
-    }),
-  )
-})
-
-it.live("method detection tolerates unavailable package managers", () =>
-  Effect.gen(function* () {
-    const test = yield* fixture((command) =>
-      command.command === "yarn"
-        ? { stdout: Buffer.from("@opencode-ai/cli@2.3.4") }
-        : { error: new AppProcess.AppProcessError({ command: command.command }) },
-    )
-    expect(yield* test.updater.method()).toBe("yarn")
-    expect(test.commands).toHaveLength(4)
-  }),
-)
-
-test("Node distribution honors the compile-time CLI name", async () => {
-  const child = Bun.spawn(
-    [
-      process.execPath,
-      "test",
-      import.meta.path,
-      "--define",
-      'OPENCODE_CLI_NAME="opencode2-node"',
-      "--test-name-pattern",
-      "^Node distribution resolves the published npm package$",
-    ],
-    { cwd: path.join(import.meta.dir, ".."), stdout: "ignore", stderr: "pipe" },
-  )
-  const [code, stderr] = await Promise.all([child.exited, new Response(child.stderr).text()])
-  expect(code, stderr).toBe(0)
-  expect(stderr).toContain("1 pass")
-})
-
-if (typeof OPENCODE_CLI_NAME === "string" && OPENCODE_CLI_NAME === "opencode2-node") {
-  it.live("Node distribution resolves the published npm package", () =>
-    Effect.gen(function* () {
-      const test = yield* fixture((command) => ({
-        stdout: Buffer.from(command.command === "npm" ? "opencode-node@2.3.4" : ""),
-      }))
-      expect(yield* test.updater.method()).toBe("npm")
-      yield* test.updater.upgrade("npm", "v2.3.4")
-      yield* test.updater.upgrade("pnpm", "v2.3.4")
-      expect(test.commands).toEqual([
-        ["npm", "list", "-g", "--depth=0", "opencode-node"],
-        ["pnpm", "list", "-g", "--depth=0", "opencode-node"],
-        ["bun", "pm", "ls", "-g"],
-        ["yarn", "global", "list"],
-        ["npm", "install", "--global", "opencode-node@2.3.4"],
-        ["pnpm", "add", "--global", "--allow-build=opencode-node", "opencode-node@2.3.4"],
-      ])
-    }),
-  )
-}

packages/cli/test/upgrade.test.ts

@@ -1,109 +0,0 @@
-import { describe, expect, test } from "bun:test"
-import { mkdtemp, rm } from "node:fs/promises"
-import os from "node:os"
-import path from "node:path"
-
-describe("upgrade command", () => {
-  test("is registered in root help and documents its options", async () => {
-    const root = await cli(["--help"], {}, "../src/index.ts")
-    const help = await cli(["upgrade", "--help"], {}, "../src/index.ts")
-    expect(root.exitCode).toBe(0)
-    expect(root.stdout).toContain("upgrade")
-    expect(help.exitCode).toBe(0)
-    expect(help.stdout).toContain("[<target>]")
-    expect(help.stdout).toContain("--method")
-    expect(help.stdout).toContain("-m")
-  })
-
-  test("detects the installation method and resolves the latest version", async () => {
-    const result = await cli([])
-    expect(result.exitCode).toBe(0)
-    expect(result.events).toEqual(["method", "latest", { method: "npm", version: "0.0.0-beta-new" }])
-    expect(result.stdout).toContain("Upgrade complete")
-  })
-
-  test("accepts an explicit version and method without detection or a version lookup", async () => {
-    const result = await cli(["v0.0.0-beta-target", "--method", "pnpm"])
-    expect(result.exitCode).toBe(0)
-    expect(result.events).toEqual([{ method: "pnpm", version: "v0.0.0-beta-target" }])
-    expect(result.stdout).toContain("0.0.0-beta-old → 0.0.0-beta-target")
-  })
-
-  test("accepts the short method flag and an explicit major upgrade", async () => {
-    const result = await cli(["2.0.0", "-m", "bun"])
-    expect(result.exitCode).toBe(0)
-    expect(result.events).toEqual([{ method: "bun", version: "2.0.0" }])
-  })
-
-  test("skips the already installed version", async () => {
-    const result = await cli(["v0.0.0-beta-old"])
-    expect(result.exitCode).toBe(0)
-    expect(result.events).toEqual(["method"])
-    expect(result.stdout).toContain("already installed")
-  })
-
-  test("requires an explicit method when detection fails", async () => {
-    const result = await cli([], { UPGRADE_TEST_METHOD: "unknown" })
-    expect(result.exitCode).toBe(1)
-    expect(result.events).toEqual(["method"])
-    expect(result.stdout).toContain("Pass --method")
-  })
-
-  test("rejects unsupported methods before attempting an upgrade", async () => {
-    const result = await cli(["--method", "brew"])
-    expect(result.exitCode).not.toBe(0)
-    expect(result.events).toEqual([])
-  })
-
-  test("reports version lookup failures without installing", async () => {
-    const result = await cli([], { UPGRADE_TEST_LATEST_ERROR: "1" })
-    expect(result.exitCode).toBe(1)
-    expect(result.events).toEqual(["method", "latest"])
-    expect(result.stdout).toContain("Update check failed")
-  })
-
-  test("reports installation failures with a nonzero exit code", async () => {
-    const result = await cli([], { UPGRADE_TEST_INSTALL_ERROR: "1" })
-    expect(result.exitCode).toBe(1)
-    expect(result.stdout).toContain("Upgrade failed")
-    expect(result.stdout).toContain("Permission denied")
-    expect(result.stdout).not.toContain("Upgrade complete")
-  })
-})
-
-async function cli(args: string[], env: Record<string, string> = {}, entry = "fixture/upgrade.ts") {
-  const root = await mkdtemp(path.join(os.tmpdir(), "opencode-upgrade-"))
-  try {
-    const child = Bun.spawn(
-      [process.execPath, "--define", 'OPENCODE_VERSION="0.0.0-beta-old"', path.join(import.meta.dir, entry), ...args],
-      {
-        cwd: path.join(import.meta.dir, ".."),
-        env: {
-          ...process.env,
-          OPENCODE_TEST_HOME: root,
-          XDG_DATA_HOME: path.join(root, "data"),
-          XDG_CONFIG_HOME: path.join(root, "config"),
-          XDG_CACHE_HOME: path.join(root, "cache"),
-          XDG_STATE_HOME: path.join(root, "state"),
-          OPENCODE_DISABLE_AUTOUPDATE: "1",
-          ...env,
-        },
-        stdout: "pipe",
-        stderr: "pipe",
-      },
-    )
-    const [stdout, stderr, exitCode] = await Promise.all([
-      new Response(child.stdout).text(),
-      new Response(child.stderr).text(),
-      child.exited,
-    ])
-    const events = stdout
-      .split("\n")
-      .filter((line) => line.startsWith("EVENT "))
-      .map((line) => JSON.parse(line.slice(6)))
-    expect(await Bun.file(path.join(root, "state", "opencode", "service-local.json")).exists()).toBe(false)
-    return { stdout, stderr, exitCode, events }
-  } finally {
-    await rm(root, { recursive: true, force: true })
-  }
-}

packages/core/src/effect/app-node-builder.ts

@@ -1,20 +1,11 @@
 import { buildLocationServiceMap } from "../location-services.js"
 import { LocationServiceMap } from "../location-service-map.js"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
-import { makeGlobalNode } from "@opencode-ai/util/effect/app-node"
 
-export function build<A, E>(root: LayerNode.Node<A, E, any>, replacements: LayerNode.Replacements = []) {
-  // Only build the location service map if it's actually needed
-  if (!LayerNode.hasUnbound(root, LocationServiceMap.node) || hasReplacement(replacements, LocationServiceMap.node))
-    return LayerNode.compile(root, replacements)
-
-  const locationMap = buildLocationServiceMap(replacements)
-  const locationMapNode = makeGlobalNode({ service: LocationServiceMap.Service, layer: locationMap, deps: [] })
-  return LayerNode.compile(root, replacements.concat([[LocationServiceMap.node, locationMapNode]]))
-}
-
-function hasReplacement(replacements: LayerNode.Replacements, node: LayerNode.Node<unknown, unknown, any>) {
-  return replacements.some(([source]) => source.name === node.name)
+export function build<A, E>(root: LayerNode.Graph<A, E>, replacements: LayerNode.Replacements = []) {
+  return LayerNode.compile(root, {
+    replacements: [LocationServiceMap.node.replace(buildLocationServiceMap(replacements)), ...replacements],
+  })
 }
 
 export * as AppNodeBuilder from "./app-node-builder.js"

packages/core/src/instance.ts

@@ -108,9 +108,9 @@ const nodes = [
   Vcs.node,
   // Start repository watches only after boot-critical filesystem and Git work.
   LocationWatcher.node,
-] as const satisfies readonly Node.LocationNode<unknown, unknown>[]
+] as const satisfies readonly Node.LocationGraph<never, unknown>[]
 
-export const graph = LayerNode.group<typeof nodes>(nodes)
+export const graph = LayerNode.group(nodes)
 
 export type Services = LayerNode.Output<typeof graph>
 export type Error = LayerNode.Error<typeof graph>
@@ -139,29 +139,23 @@ export interface Options {
 // source still honors explicit plugin operations from wellknown and
 // host-injected config.
 const vanillaReplacements: LayerNode.Replacements = [
-  [Config.node, Config.configured({ project: false, global: false })],
-  [InstructionDiscovery.node, InstructionDiscovery.configured({ project: false, global: false })],
+  Config.node.replace(Config.configured({ project: false, global: false })),
+  InstructionDiscovery.node.replace(InstructionDiscovery.configured({ project: false, global: false })),
 ]
 
 // One instance is one compiled, fresh copy of the graph standing on a directory.
 export function layer(ref: Location.Ref, options: Options = {}) {
   const startedAt = performance.now()
   // Ordered: vanilla defaults, then caller replacements (which win over the
-  // defaults), then bound pairs (which win over everything).
-  const allReplacements: LayerNode.Replacements = [
+  // defaults), then instance bindings (which win over everything).
+  const replacements: LayerNode.Replacements = [
     ...(options.discovery === false ? vanillaReplacements : []),
     ...(options.replacements ?? []),
-    [Location.node, Location.boundNode(ref, { discovery: options.discovery })],
-    [InstancePlugins.node, InstancePlugins.bound(options.plugins ?? [])],
+    Location.node.replace(Location.boundNode(ref, { discovery: options.discovery })),
+    InstancePlugins.node.replace(InstancePlugins.bound(options.plugins ?? [])),
   ]
-  // Apply replacements during hoist, not afterward: replacements can
-  // introduce new tagged dependencies (Location.boundNode depends on
-  // Project), and the hoist walk is the only pass that can still slice
-  // those back out.
-  const location = LayerNode.hoist(graph, Node.tags.values.global, allReplacements)
 
-  return LayerNode.compile(location.node).pipe(
-    Layer.fresh,
+  return LayerNode.compile(graph, { replacements, shared: Node.tags.values.global }).pipe(
     Layer.tap(() =>
       Effect.logInfo("location services booted", {
         directory: ref.directory,
@@ -169,6 +163,5 @@ export function layer(ref: Location.Ref, options: Options = {}) {
         durationMs: Math.round(performance.now() - startedAt),
       }),
     ),
-    Layer.provide(LayerNode.compile(location.hoisted)),
   )
 }

packages/core/src/persistent-pty/index.ts

@@ -112,7 +112,7 @@ export interface Interface {
 
 export class Service extends Context.Service<Service, Interface>()("@opencode/PersistentPty") {}
 
-export const configured = (options: Options = {}) =>
+const makeLayer = (options: Options = {}) =>
   Layer.effect(
     Service,
     Effect.gen(function* () {
@@ -361,8 +361,14 @@ export const configured = (options: Options = {}) =>
     }),
   )
 
-export const layer = configured()
-export const node = makeGlobalNode({ service: Service, layer, deps: [Bus.node, Global.node] })
+export const layer = makeLayer()
+export const configured = (options?: Options) =>
+  makeGlobalNode({
+    service: Service,
+    layer: options === undefined ? layer : makeLayer(options),
+    deps: [Bus.node, Global.node],
+  })
+export const node = configured()
 
 const request = (daemon: DaemonTransport, value: object, start = false) =>
   daemon.request(value, start).pipe(Effect.mapError(unavailable))

packages/core/src/session.ts

@@ -3,8 +3,9 @@ export * from "./session/schema.js"
 
 import { Cause, Effect, Layer, Schema, Context, RcMap, Stream, Scope } from "effect"
 import { ListAnchor } from "@opencode-ai/schema/session"
-import { and, desc, eq } from "drizzle-orm"
+import { and, asc, desc, eq, gt, isNull, like, lt, or, type SQL } from "drizzle-orm"
 import { Project } from "./project.js"
+import { Workspace } from "@opencode-ai/schema/workspace"
 import { Model } from "@opencode-ai/schema/model"
 import { Location } from "./location.js"
 import { SessionMessage } from "./session/message.js"
@@ -12,13 +13,14 @@ import { PromptInput } from "@opencode-ai/schema/prompt-input"
 import { Bus } from "./bus.js"
 import { Database } from "./database/database.js"
 import { SessionProjector } from "./session/projector.js"
-import { SessionMessageTable } from "./session/sql.js"
+import { SessionMessageTable, SessionTable } from "./session/sql.js"
 import { SessionSchema } from "./session/schema.js"
-import { AbsolutePath, RelativePath } from "./schema.js"
+import { AbsolutePath, PositiveInt, RelativePath } from "./schema.js"
 import { Agent } from "@opencode-ai/schema/agent"
 import { App } from "./app.js"
 import { Slug } from "./util/slug.js"
 import path from "path"
+import { fromRow } from "./session/info.js"
 import { SessionRunner } from "./session/runner/index.js"
 import { SessionStore } from "./session/store.js"
 import { SessionExecution } from "./session/execution.js"
@@ -56,6 +58,7 @@ import { Job } from "./job.js"
 import { Command } from "./command.js"
 import { Global } from "@opencode-ai/util/global"
 import { SessionEnvironment } from "./session/environment.js"
+import { SessionHistory } from "./session/history.js"
 import { InstructionEntry } from "./session/instruction-entry.js"
 
 // get project -> project.locations
@@ -69,8 +72,30 @@ import { InstructionEntry } from "./session/instruction-entry.js"
 
 export { ListAnchor }
 
-export const ListInput = SessionStore.ListInput
-export type ListInput = SessionStore.ListInput
+const ListInputBase = {
+  workspaceID: Workspace.ID.pipe(Schema.optional),
+  search: Schema.String.pipe(Schema.optional),
+  limit: PositiveInt.pipe(Schema.optional),
+  order: Schema.Literals(["asc", "desc"]).pipe(Schema.optional),
+  parentID: Schema.NullOr(SessionSchema.ID).pipe(Schema.optional),
+  anchor: ListAnchor.pipe(Schema.optional),
+}
+
+const ListDirectoryInput = Schema.Struct({
+  ...ListInputBase,
+  directory: AbsolutePath,
+})
+
+const ListProjectInput = Schema.Struct({
+  ...ListInputBase,
+  project: Project.ID,
+  subpath: RelativePath.pipe(Schema.optional),
+})
+
+const ListAllInput = Schema.Struct(ListInputBase)
+
+export const ListInput = Schema.Union([ListDirectoryInput, ListProjectInput, ListAllInput])
+export type ListInput = typeof ListInput.Type
 
 type CreateBaseInput = {
   id?: SessionSchema.ID
@@ -136,9 +161,15 @@ export interface Interface {
   }) => Effect.Effect<SessionEnvironment.Variables | undefined, NotFoundError>
   readonly view: (input: { sessionID: SessionSchema.ID; idle: number }) => Effect.Effect<void, NotFoundError>
   readonly remove: (sessionID: SessionSchema.ID) => Effect.Effect<void, NotFoundError>
-  readonly messages: (
-    input: SessionStore.MessagesInput,
-  ) => Effect.Effect<SessionMessage.Info[], NotFoundError | MessageDecodeError>
+  readonly messages: (input: {
+    sessionID: SessionSchema.ID
+    limit?: number
+    order?: "asc" | "desc"
+    cursor?: {
+      id: SessionMessage.ID
+      direction: "previous" | "next"
+    }
+  }) => Effect.Effect<SessionMessage.Info[], NotFoundError | MessageDecodeError>
   readonly message: (input: {
     sessionID: SessionSchema.ID
     messageID: SessionMessage.ID
@@ -378,12 +409,83 @@ const layer = Layer.effect(
         yield* bus.publish(SessionEvent.Deleted, { sessionID })
         yield* bus.remove(sessionID)
       }),
-      list: Effect.fn("Session.list")(function* (input) {
-        return { data: yield* store.list(input) }
+      list: Effect.fn("Session.list")(function* (input = {}) {
+        const direction = input.anchor?.direction ?? "next"
+        const requestedOrder = input.order ?? "desc"
+        const order = direction === "previous" ? (requestedOrder === "asc" ? "desc" : "asc") : requestedOrder
+        const sortColumn = SessionTable.time_updated
+        const conditions: SQL[] = []
+        if ("directory" in input) conditions.push(eq(SessionTable.directory, input.directory))
+        if (input.workspaceID) conditions.push(eq(SessionTable.workspace_id, input.workspaceID))
+        if ("project" in input) conditions.push(eq(SessionTable.project_id, input.project))
+        if ("project" in input && input.subpath !== undefined) conditions.push(eq(SessionTable.path, input.subpath))
+        if (input.search) conditions.push(like(SessionTable.title, `%${input.search}%`))
+        if (input.parentID !== undefined)
+          conditions.push(
+            input.parentID === null ? isNull(SessionTable.parent_id) : eq(SessionTable.parent_id, input.parentID),
+          )
+        if (input.anchor) {
+          conditions.push(
+            order === "asc"
+              ? or(
+                  gt(sortColumn, input.anchor.time),
+                  and(eq(sortColumn, input.anchor.time), gt(SessionTable.id, input.anchor.id)),
+                )!
+              : or(
+                  lt(sortColumn, input.anchor.time),
+                  and(eq(sortColumn, input.anchor.time), lt(SessionTable.id, input.anchor.id)),
+                )!,
+          )
+        }
+        const query = db
+          .select()
+          .from(SessionTable)
+          .where(conditions.length > 0 ? and(...conditions) : undefined)
+          .orderBy(
+            order === "asc" ? asc(sortColumn) : desc(sortColumn),
+            order === "asc" ? asc(SessionTable.id) : desc(SessionTable.id),
+          )
+        const rows = yield* (input.limit === undefined ? query.all() : query.limit(input.limit).all()).pipe(
+          Effect.orDie,
+        )
+        return { data: (direction === "previous" ? rows.toReversed() : rows).map((row) => fromRow(row)) }
       }),
       messages: Effect.fn("Session.messages")(function* (input) {
         yield* result.get(input.sessionID)
-        return yield* store.messages(input)
+        const direction = input.cursor?.direction ?? "next"
+        const requestedOrder = input.order ?? "desc"
+        const order = direction === "previous" ? (requestedOrder === "asc" ? "desc" : "asc") : requestedOrder
+        const anchor = input.cursor
+          ? yield* db
+              .select({ seq: SessionMessageTable.seq })
+              .from(SessionMessageTable)
+              .where(
+                and(eq(SessionMessageTable.session_id, input.sessionID), eq(SessionMessageTable.id, input.cursor.id)),
+              )
+              .get()
+              .pipe(Effect.orDie)
+          : undefined
+        if (input.cursor && !anchor) return []
+        const boundary = anchor
+          ? order === "asc"
+            ? gt(SessionMessageTable.seq, anchor.seq)
+            : lt(SessionMessageTable.seq, anchor.seq)
+          : undefined
+        const where = boundary
+          ? and(eq(SessionMessageTable.session_id, input.sessionID), boundary)
+          : eq(SessionMessageTable.session_id, input.sessionID)
+        const query = db
+          .select()
+          .from(SessionMessageTable)
+          .where(where)
+          .orderBy(order === "asc" ? asc(SessionMessageTable.seq) : desc(SessionMessageTable.seq))
+        const rows = yield* (input.limit === undefined ? query.all() : query.limit(input.limit).all()).pipe(
+          Effect.orDie,
+        )
+        return yield* Effect.forEach(
+          direction === "previous" ? rows.toReversed() : rows,
+          SessionHistory.decodeMessageRow,
+        )
       }),
       message: (input) => sessions.forSession(input.sessionID).message(input.messageID),
       updateMessage: (input) => sessions.forSession(input.sessionID).updateMessage(input),

packages/core/src/session/store.ts

@@ -1,10 +1,7 @@
 export * as SessionStore from "./store.js"
 
-import { and, asc, desc, eq, gt, isNotNull, isNull, like, lt, notInArray, or, sql, type SQL } from "drizzle-orm"
-import { Context, Effect, Layer, Schema } from "effect"
-import { Project } from "@opencode-ai/schema/project"
-import { Workspace } from "@opencode-ai/schema/workspace"
-import { AbsolutePath, PositiveInt, RelativePath } from "@opencode-ai/schema/schema"
+import { and, eq, isNotNull, isNull, notInArray, sql } from "drizzle-orm"
+import { Context, Effect, Layer } from "effect"
 import { Database } from "../database/database.js"
 import { makeGlobalNode } from "@opencode-ai/util/effect/app-node"
 import { SessionHistory } from "./history.js"
@@ -14,45 +11,8 @@ import { Session } from "@opencode-ai/schema/session"
 import { SessionMessageTable, SessionTable } from "./sql.js"
 import { fromRow } from "./info.js"
 
-const ListInputBase = {
-  workspaceID: Workspace.ID.pipe(Schema.optional),
-  search: Schema.String.pipe(Schema.optional),
-  limit: PositiveInt.pipe(Schema.optional),
-  order: Schema.Literals(["asc", "desc"]).pipe(Schema.optional),
-  parentID: Schema.NullOr(Session.ID).pipe(Schema.optional),
-  anchor: Session.ListAnchor.pipe(Schema.optional),
-}
-
-const ListDirectoryInput = Schema.Struct({
-  ...ListInputBase,
-  directory: AbsolutePath,
-})
-
-const ListProjectInput = Schema.Struct({
-  ...ListInputBase,
-  project: Project.ID,
-  subpath: RelativePath.pipe(Schema.optional),
-})
-
-const ListAllInput = Schema.Struct(ListInputBase)
-
-export const ListInput = Schema.Union([ListDirectoryInput, ListProjectInput, ListAllInput])
-export type ListInput = typeof ListInput.Type
-
-export type MessagesInput = {
-  sessionID: Session.ID
-  limit?: number
-  order?: "asc" | "desc"
-  cursor?: {
-    id: SessionMessage.ID
-    direction: "previous" | "next"
-  }
-}
-
 export interface Interface {
   readonly get: (sessionID: Session.ID) => Effect.Effect<Session.Info | undefined>
-  readonly list: (input?: ListInput) => Effect.Effect<Session.Info[]>
-  readonly messages: (input: MessagesInput) => Effect.Effect<SessionMessage.Info[], MessageDecodeError>
   readonly context: (sessionID: Session.ID) => Effect.Effect<SessionMessage.Info[], MessageDecodeError>
   readonly message: (
     messageID: SessionMessage.ID,
@@ -95,83 +55,6 @@ const layer = Layer.effect(
         const row = yield* db.select().from(SessionTable).where(eq(SessionTable.id, sessionID)).get().pipe(Effect.orDie)
         return row ? fromRow(row) : undefined
       }),
-      list: Effect.fn("SessionStore.list")(function* (input = {}) {
-        const direction = input.anchor?.direction ?? "next"
-        const requestedOrder = input.order ?? "desc"
-        const order = direction === "previous" ? (requestedOrder === "asc" ? "desc" : "asc") : requestedOrder
-        const sortColumn = SessionTable.time_updated
-        const conditions: SQL[] = []
-        if ("directory" in input) conditions.push(eq(SessionTable.directory, input.directory))
-        if (input.workspaceID) conditions.push(eq(SessionTable.workspace_id, input.workspaceID))
-        if ("project" in input) conditions.push(eq(SessionTable.project_id, input.project))
-        if ("project" in input && input.subpath !== undefined) conditions.push(eq(SessionTable.path, input.subpath))
-        if (input.search) conditions.push(like(SessionTable.title, `%${input.search}%`))
-        if (input.parentID !== undefined)
-          conditions.push(
-            input.parentID === null ? isNull(SessionTable.parent_id) : eq(SessionTable.parent_id, input.parentID),
-          )
-        if (input.anchor) {
-          conditions.push(
-            order === "asc"
-              ? or(
-                  gt(sortColumn, input.anchor.time),
-                  and(eq(sortColumn, input.anchor.time), gt(SessionTable.id, input.anchor.id)),
-                )!
-              : or(
-                  lt(sortColumn, input.anchor.time),
-                  and(eq(sortColumn, input.anchor.time), lt(SessionTable.id, input.anchor.id)),
-                )!,
-          )
-        }
-        const query = db
-          .select()
-          .from(SessionTable)
-          .where(conditions.length > 0 ? and(...conditions) : undefined)
-          .orderBy(
-            order === "asc" ? asc(sortColumn) : desc(sortColumn),
-            order === "asc" ? asc(SessionTable.id) : desc(SessionTable.id),
-          )
-        const rows = yield* (input.limit === undefined ? query.all() : query.limit(input.limit).all()).pipe(
-          Effect.orDie,
-        )
-        return (direction === "previous" ? rows.toReversed() : rows).map((row) => fromRow(row))
-      }),
-      messages: Effect.fn("SessionStore.messages")(function* (input) {
-        const direction = input.cursor?.direction ?? "next"
-        const requestedOrder = input.order ?? "desc"
-        const order = direction === "previous" ? (requestedOrder === "asc" ? "desc" : "asc") : requestedOrder
-        const anchor = input.cursor
-          ? yield* db
-              .select({ seq: SessionMessageTable.seq })
-              .from(SessionMessageTable)
-              .where(
-                and(eq(SessionMessageTable.session_id, input.sessionID), eq(SessionMessageTable.id, input.cursor.id)),
-              )
-              .get()
-              .pipe(Effect.orDie)
-          : undefined
-        if (input.cursor && !anchor) return []
-        const boundary = anchor
-          ? order === "asc"
-            ? gt(SessionMessageTable.seq, anchor.seq)
-            : lt(SessionMessageTable.seq, anchor.seq)
-          : undefined
-        const where = boundary
-          ? and(eq(SessionMessageTable.session_id, input.sessionID), boundary)
-          : eq(SessionMessageTable.session_id, input.sessionID)
-        const query = db
-          .select()
-          .from(SessionMessageTable)
-          .where(where)
-          .orderBy(order === "asc" ? asc(SessionMessageTable.seq) : desc(SessionMessageTable.seq))
-        const rows = yield* (input.limit === undefined ? query.all() : query.limit(input.limit).all()).pipe(
-          Effect.orDie,
-        )
-        return yield* Effect.forEach(
-          direction === "previous" ? rows.toReversed() : rows,
-          SessionHistory.decodeMessageRow,
-        )
-      }),
       context: Effect.fn("SessionStore.context")((sessionID) => SessionHistory.load(db, sessionID)),
       message: Effect.fn("SessionStore.message")(function* (messageID) {
         const row = yield* db

packages/core/test/agent.test.ts

@@ -22,8 +22,8 @@ const globalLayer = Layer.succeed(Global.Service, Global.Service.of(global))
 
 const it = testEffect(
   AppNodeBuilder.build(LayerNode.group([Agent.node, Bus.node, Location.node]), [
-    [Global.node, globalLayer],
-    [Location.node, locationLayer],
+    Global.node.replace(globalLayer),
+    Location.node.replace(locationLayer),
   ]) as unknown as Layer.Layer<unknown, never>,
 )
 

packages/core/test/bus-session-routing.test.ts

@@ -21,7 +21,7 @@ import { testEffect } from "./lib/effect"
 
 const it = testEffect(
   AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, SessionProjector.node]), [
-    [Bus.node, Bus.configured({ persist: true })],
+    Bus.node.replace(Bus.configured({ persist: true })),
   ]),
 )
 const a = Location.Ref.make({ directory: AbsolutePath.make("/a") })

packages/core/test/bus.test.ts

@@ -100,12 +100,14 @@ const tail = (bus: Bus.Interface, input: { aggregateID: string; after?: number }
 
 const it = testEffect(
   AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, Location.node]), [
-    [Location.node, locationLayer],
-    [Bus.node, Bus.configured({ persist: true })],
+    Location.node.replace(locationLayer),
+    Bus.node.replace(Bus.configured({ persist: true })),
   ]),
 )
 const itWithoutLocation = testEffect(
-  AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node]), [[Bus.node, Bus.configured({ persist: true })]]),
+  AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node]), [
+    Bus.node.replace(Bus.configured({ persist: true })),
+  ]),
 )
 const itWithoutPersistence = testEffect(AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node])))
 
@@ -631,8 +633,7 @@ describe("Bus", () => {
       const continueRead = yield* Deferred.make<void>()
       let pause = true
       const eventLayer = AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node]), [
-        [
-          Bus.node,
+        Bus.node.replace(
           Bus.configured({
             persist: true,
             beforeAggregateRead: () =>
@@ -640,7 +641,7 @@ describe("Bus", () => {
                 ? Deferred.succeed(readStarted, undefined).pipe(Effect.andThen(Deferred.await(continueRead)))
                 : Effect.void,
           }),
-        ],
+        ),
       ])
 
       yield* Effect.gen(function* () {
@@ -1318,7 +1319,7 @@ describe("Bus", () => {
   it.effect("log replays across configured read pages", () =>
     Effect.gen(function* () {
       const eventLayer = AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node]), [
-        [Bus.node, Bus.configured({ persist: true, logReadPageSize: 2 })],
+        Bus.node.replace(Bus.configured({ persist: true, logReadPageSize: 2 })),
       ])
 
       yield* Effect.gen(function* () {
@@ -1351,8 +1352,7 @@ describe("Bus", () => {
       const releaseRead = yield* Deferred.make<void>()
       const firstRead = yield* Ref.make(true)
       const eventLayer = AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node]), [
-        [
-          Bus.node,
+        Bus.node.replace(
           Bus.configured({
             persist: true,
             beforeAggregateRead: () =>
@@ -1363,7 +1363,7 @@ describe("Bus", () => {
                 }),
               ),
           }),
-        ],
+        ),
       ])
 
       yield* Effect.gen(function* () {

packages/core/test/catalog.test.ts

@@ -25,7 +25,7 @@ const locationLayer = Layer.succeed(
 )
 const catalogLayer = AppNodeBuilder.build(
   LayerNode.group([Catalog.node, Bus.node, Credential.node, Integration.node]),
-  [[Location.node, locationLayer]],
+  [Location.node.replace(locationLayer)],
 )
 const it = testEffect(catalogLayer)
 
@@ -48,7 +48,7 @@ describe("Catalog", () => {
   it.effect("derives availability from active credentials without changing provider state", () => {
     const integrationID = Integration.ID.make("test")
     const localCatalogLayer = Layer.fresh(
-      AppNodeBuilder.build(LayerNode.group([Catalog.node, Credential.node]), [[Location.node, locationLayer]]),
+      AppNodeBuilder.build(LayerNode.group([Catalog.node, Credential.node]), [Location.node.replace(locationLayer)]),
     )
 
     return Effect.gen(function* () {
@@ -78,7 +78,7 @@ describe("Catalog", () => {
     const providerID = Provider.ID.make("remote")
     const localCatalogLayer = Layer.fresh(
       AppNodeBuilder.build(LayerNode.group([Catalog.node, Credential.node, Integration.node]), [
-        [Location.node, locationLayer],
+        Location.node.replace(locationLayer),
       ]),
     )
 
@@ -108,7 +108,7 @@ describe("Catalog", () => {
     const providerID = Provider.ID.make("remote")
     const localCatalogLayer = Layer.fresh(
       AppNodeBuilder.build(LayerNode.group([Catalog.node, Credential.node, Integration.node]), [
-        [Location.node, locationLayer],
+        Location.node.replace(locationLayer),
       ]),
     )
 

packages/core/test/codemode.test.ts

@@ -35,7 +35,7 @@ describe("CodeMode", () => {
       Effect.scoped,
       Effect.provide(
         AppNodeBuilder.build(Tool.node, [
-          [Location.node, Location.boundNode({ directory: AbsolutePath.make("/project") })],
+          Location.node.replace(Location.boundNode({ directory: AbsolutePath.make("/project") })),
         ]),
       ),
     ),

packages/core/test/codemode/instructions.test.ts

@@ -85,7 +85,7 @@ describe("CodeModeInstructions", () => {
       execute: () => Effect.succeed({ output: "zeta" }),
     }
     const layer = AppNodeBuilder.build(Tool.node, [
-      [Location.node, Location.boundNode({ directory: AbsolutePath.make("/project") })],
+      Location.node.replace(Location.boundNode({ directory: AbsolutePath.make("/project") })),
     ])
 
     return Effect.gen(function* () {

packages/core/test/config/command.test.ts

@@ -43,10 +43,10 @@ const it = testEffect(
   AppNodeBuilder.build(
     LayerNode.group([Command.node, Bus.node, FSUtil.node, AppProcess.node, Location.node, ShellSelect.node]),
     [
-      [Mcp.node, emptyMcpLayer],
-      [Config.node, emptyConfigLayer],
-      [Location.node, testLocationLayer],
-      [ShellSelect.node, shellLayer],
+      Mcp.node.replace(emptyMcpLayer),
+      Config.node.replace(emptyConfigLayer),
+      Location.node.replace(testLocationLayer),
+      ShellSelect.node.replace(shellLayer),
     ],
   ),
 )
@@ -340,17 +340,16 @@ describeNative("ConfigCommandPlugin native watcher", () => {
               ShellSelect.node,
             ]),
             [
-              [
-                Location.node,
+              Location.node.replace(
                 Layer.succeed(
                   Location.Service,
                   Location.Service.of(location({ directory: AbsolutePath.make(path.join(tmp, "project")) })),
                 ),
-              ],
-              [Global.node, Global.layerWith({ config: global, home: path.join(global, "home") })],
-              [ShellSelect.node, shellLayer],
-              [Credential.node, emptyCredentialNode],
-              [WellKnown.node, emptyWellknownNode],
+              ),
+              Global.node.replace(Global.layerWith({ config: global, home: path.join(global, "home") })),
+              ShellSelect.node.replace(shellLayer),
+              Credential.node.replace(emptyCredentialNode),
+              WellKnown.node.replace(emptyWellknownNode),
             ],
           ),
         ),

packages/core/test/config/compaction.test.ts

@@ -40,13 +40,12 @@ const it = testEffect(
   Layer.merge(
     config,
     AppNodeBuilder.build(LayerNode.group([SessionCompaction.node, SessionModelRequest.node, Config.node, Bus.node]), [
-      [
-        llmClient,
+      llmClient.replace(
         Layer.mock(LLMClient.Service)({
           stream: () => Stream.make(LLMEvent.textDelta({ id: "summary", text: "summary" })),
         }),
-      ],
-      [Config.node, config],
+      ),
+      Config.node.replace(config),
     ]),
   ),
 )

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

@@ -55,12 +55,12 @@ function testLayer(
     ),
   )
   const built = AppNodeBuilder.build(LayerNode.group([Config.node, Bus.node]), [
-    [Config.node, Config.configured(options)],
-    [Location.node, locationLayer],
-    [Global.node, Global.layerWith({ config: globalDirectory, home: path.join(globalDirectory, "home") })],
-    [Credential.node, credentialNode],
-    [WellKnown.node, wellknownNode],
-    [Watcher.node, watcher],
+    Config.node.replace(Config.configured(options)),
+    Location.node.replace(locationLayer),
+    Global.node.replace(Global.layerWith({ config: globalDirectory, home: path.join(globalDirectory, "home") })),
+    Credential.node.replace(credentialNode),
+    WellKnown.node.replace(wellknownNode),
+    Watcher.node.replace(watcher),
   ])
   // Merge the watcher layer by reference so Watcher.Test resolves to the same
   // memoized instance the built graph uses.
@@ -311,16 +311,15 @@ describe("Config", () => {
           }).pipe(
             Effect.provide(
               AppNodeBuilder.build(LayerNode.group([Config.node, Bus.node]), [
-                [
-                  Location.node,
+                Location.node.replace(
                   Layer.succeed(
                     Location.Service,
                     Location.Service.of(location({ directory: AbsolutePath.make(project) })),
                   ),
-                ],
-                [Global.node, Global.layerWith({ config: global, home: path.join(global, "home") })],
-                [Credential.node, emptyCredentialNode],
-                [WellKnown.node, emptyWellknownNode],
+                ),
+                Global.node.replace(Global.layerWith({ config: global, home: path.join(global, "home") })),
+                Credential.node.replace(emptyCredentialNode),
+                WellKnown.node.replace(emptyWellknownNode),
               ]),
             ),
           )

packages/core/test/config/plugin.test.ts

@@ -28,13 +28,13 @@ import { testEffect } from "../lib/effect"
 
 const it = testEffect(
   AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, SdkPlugins.node, LocationServiceMap.node]), [
-    [Global.node, tempGlobalLayer],
+    Global.node.replace(tempGlobalLayer),
   ]),
 )
 const staticIt = testEffect(
   AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, SdkPlugins.node, LocationServiceMap.node]), [
-    [ConfigPluginSource.node, ConfigPluginSource.empty],
-    [Global.node, tempGlobalLayer],
+    ConfigPluginSource.node.replace(ConfigPluginSource.empty),
+    Global.node.replace(tempGlobalLayer),
   ]),
 )
 const refreshNpm = makeGlobalNode({
@@ -65,10 +65,7 @@ const refreshNpm = makeGlobalNode({
 const refreshIt = testEffect(
   AppNodeBuilder.build(
     LayerNode.group([Database.node, Bus.node, SdkPlugins.node, LocationServiceMap.node, Global.node]),
-    [
-      [Global.node, tempGlobalLayer],
-      [Npm.node, refreshNpm],
-    ],
+    [Global.node.replace(tempGlobalLayer), Npm.node.replace(refreshNpm)],
   ),
 )
 

packages/core/test/config/skill.test.ts

@@ -86,14 +86,13 @@ const discover = (directory: string, global: string) =>
   }).pipe(
     Effect.provide(
       AppNodeBuilder.build(LayerNode.group([Config.node, Bus.node]), [
-        [
-          Location.node,
+        Location.node.replace(
           Layer.succeed(Location.Service, Location.Service.of(location({ directory: AbsolutePath.make(directory) }))),
-        ],
-        [Global.node, Global.layerWith({ config: global, home: path.join(global, "home") })],
-        [Credential.node, emptyCredentialNode],
-        [WellKnown.node, emptyWellknownNode],
-        [Watcher.node, Watcher.testLayer],
+        ),
+        Global.node.replace(Global.layerWith({ config: global, home: path.join(global, "home") })),
+        Credential.node.replace(emptyCredentialNode),
+        WellKnown.node.replace(emptyWellknownNode),
+        Watcher.node.replace(Watcher.testLayer),
       ]),
     ),
   )

packages/core/test/config/snapshot.test.ts

@@ -51,8 +51,8 @@ describe("ConfigSnapshotPlugin.Plugin", () => {
           }).pipe(
             Effect.provide(
               AppNodeBuilder.build(Snapshot.node, [
-                [Location.node, Location.boundNode(Location.Ref.make({ directory: AbsolutePath.make(project) }))],
-                [Global.node, Global.layerWith({ data: tmp.path, config: path.join(tmp.path, "config") })],
+                Location.node.replace(Location.boundNode(Location.Ref.make({ directory: AbsolutePath.make(project) }))),
+                Global.node.replace(Global.layerWith({ data: tmp.path, config: path.join(tmp.path, "config") })),
               ]),
             ),
           )

packages/core/test/config/tool-output.test.ts

@@ -44,7 +44,9 @@ describe("ConfigToolOutputPlugin.Plugin", () => {
           }
           yield* Effect.die(new Error("Timed out waiting for tool output config reload"))
         }).pipe(
-          Effect.provide(AppNodeBuilder.build(ToolOutput.node, [[Global.node, Global.layerWith({ data: tmp.path })]])),
+          Effect.provide(
+            AppNodeBuilder.build(ToolOutput.node, [Global.node.replace(Global.layerWith({ data: tmp.path }))]),
+          ),
         ),
       (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]()),
     ).pipe(

packages/core/test/effect/layer-node/layer-node-types.test.ts

@@ -13,131 +13,218 @@ class OtherError {
   readonly _tag = "OtherError"
 }
 
-const tags = LayerNode.tags({ app: [] })
-const make = tags.make("app")
-const build = <A, E>(root: LayerNode.Node<A, E, any>) => LayerNode.compile(root) as Layer.Layer<A, E>
-const aLayer = Layer.succeed(A, A.of({}))
-const bLayer = Layer.effect(B, Effect.as(A, B.of({})))
-const cLayer = Layer.effect(
-  C,
-  Effect.gen(function* () {
-    yield* A
-    yield* B
-    return C.of({})
-  }),
-)
-const failingA = Layer.effect(A, Effect.fail(new LayerError()))
-const a = make({ service: A, layer: aLayer, deps: [] })
-const b = make({ service: B, layer: bLayer, deps: [a] })
-const c = make({ service: C, layer: cLayer, deps: [a, b] })
-const failing = make({ service: A, layer: failingA, deps: [] })
-const dependent = make({ service: B, layer: bLayer, deps: [failing] })
-const inputA = LayerNode.unbound(A, tags.values.app)
-const inputDependent = make({ service: B, layer: bLayer, deps: [inputA] })
+// Keep intentionally invalid expressions out of runtime execution.
+const contracts = (tag: LayerNode.Tag<"app"> | LayerNode.Tag<"other">, flag: boolean) => {
+  const tags = LayerNode.tags({ app: [] })
+  const make = tags.make("app")
+  const aLayer = Layer.succeed(A, A.of({}))
+  const bLayer = Layer.effect(B, Effect.as(A, B.of({})))
+  const cLayer = Layer.effect(
+    C,
+    Effect.gen(function* () {
+      yield* A
+      yield* B
+      return C.of({})
+    }),
+  )
+  const a = make({ service: A, layer: aLayer, deps: [] })
+  const b = make({ service: B, layer: bLayer, deps: [a] })
+  const c = make({ service: C, layer: cLayer, deps: [a, b] })
+  const ab = make({ name: "a-and-b", layer: Layer.mergeAll(aLayer, Layer.succeed(B, {})), deps: [] })
+  const failing = make({ service: A, layer: Layer.effect(A, Effect.fail(new LayerError())), deps: [] })
+  const dependent = make({ service: B, layer: bLayer, deps: [failing] })
+  const inputA = LayerNode.unbound(A, tags.values.app)
+  const group = LayerNode.group([a, b])
 
-make({ name: "manual-a", layer: aLayer, deps: [] })
+  make({ name: "manual-a", layer: aLayer, deps: [] })
+  // @ts-expect-error A node must have a service or name
+  make({ layer: aLayer, deps: [] })
+  // @ts-expect-error Service and name are mutually exclusive
+  make({ service: A, name: "a", layer: aLayer, deps: [] })
+  // @ts-expect-error An explicit tagged contract requires a corresponding runtime tag
+  LayerNode.make<typeof aLayer, readonly [], typeof tags.values.app>({ service: A, layer: aLayer, deps: [] })
+  // @ts-expect-error B requires A
+  make({ service: B, layer: bLayer, deps: [] })
+  // @ts-expect-error C requires A and B
+  make({ service: C, layer: cLayer, deps: [a] })
+  const erasedLayer: Layer.Any = bLayer
+  // @ts-expect-error Erasing a Layer's contract cannot hide its inputs and errors
+  make({ service: B, layer: erasedLayer, deps: [] })
 
-// @ts-expect-error A node must have a service or name
-make({ layer: aLayer, deps: [] })
+  LayerNode.compile(c) satisfies Layer.Layer<C, never, never>
+  LayerNode.compile(dependent) satisfies Layer.Layer<B, LayerError, never>
+  LayerNode.compile(group) satisfies Layer.Layer<A | B, never, never>
+  LayerNode.compile(LayerNode.group([])) satisfies Layer.Layer<never>
+  // @ts-expect-error An empty graph cannot supply arbitrary services
+  LayerNode.compile(LayerNode.group([])) satisfies Layer.Layer<A>
+  LayerNode.compile(inputA, { replacements: [inputA.replace(a)] }) satisfies Layer.Layer<A, never, never>
+  // @ts-expect-error A is a private dependency, not a root output
+  LayerNode.compile(c) satisfies Layer.Layer<A | C>
+  // @ts-expect-error Dependency failures are not erased
+  LayerNode.compile(dependent) satisfies Layer.Layer<B>
 
-// @ts-expect-error Service and name are mutually exclusive
-make({ service: A, name: "a", layer: aLayer, deps: [] })
-
-// @ts-expect-error B requires A
-make({ service: B, layer: bLayer, deps: [] })
-
-// @ts-expect-error C requires A and B
-make({ service: C, layer: cLayer, deps: [a] })
-
-const closed = build(LayerNode.group([c]))
-const closedWithError = build(LayerNode.group([dependent]))
-const checkClosed: Layer.Layer<C, never, never> = closed
-const checkError: Layer.Layer<B, LayerError, never> = closedWithError
-void checkClosed
-void checkError
-
-LayerNode.compile(a, [[a, Layer.succeed(A, A.of({}))]])
-LayerNode.compile(a, [[a, make({ service: A, layer: Layer.succeed(A, A.of({})), deps: [] })]])
-
-// @ts-expect-error Replacement must provide A
-LayerNode.compile(a, [[a, Layer.succeed(B, B.of({}))]])
-
-// @ts-expect-error Node replacement must provide A
-const invalidNodeReplacement = () => LayerNode.compile(a, [[a, b]])
-void invalidNodeReplacement
-
-// @ts-expect-error Replacement cannot introduce a new error
-LayerNode.compile(a, [[a, Layer.effect(A, Effect.fail(new OtherError()))]])
-
-const invalidNodeErrorReplacement = () =>
+  const replacements: LayerNode.Replacements = [a.replace(aLayer), a.replace(ab), failing.replace(a)]
+  const replacement: LayerNode.Replacement = a.replace(Layer.mergeAll(aLayer, Layer.succeed(B, {})))
+  LayerNode.compile(a, { replacements: [...replacements, replacement] })
+  inputA.replace(a)
+  a.replace(a)
+  // @ts-expect-error Closed layer replacements must provide every source output
+  ab.replace(aLayer)
+  // @ts-expect-error Node replacements must provide every source output
+  ab.replace(a)
+  // @ts-expect-error Replacement must provide A
+  a.replace(Layer.succeed(B, {}))
+  // @ts-expect-error Node replacement must provide A
+  a.replace(b)
+  // @ts-expect-error Raw layers with inputs are not closed
+  a.replace(Layer.effect(A, Effect.as(B, A.of({}))))
+  // @ts-expect-error Replacement cannot introduce a new error
+  a.replace(Layer.effect(A, Effect.fail(new OtherError())))
   // @ts-expect-error Node replacement cannot introduce a new error
-  LayerNode.compile(a, [[a, make({ service: A, layer: Layer.effect(A, Effect.fail(new OtherError())), deps: [] })]])
-void invalidNodeErrorReplacement
+  a.replace(failing)
+  // @ts-expect-error Existing errors do not authorize unrelated replacement errors
+  failing.replace(Layer.effect(A, Effect.fail(new OtherError())))
+  // @ts-expect-error Every alternative of a node replacement must supply A
+  a.replace(flag ? a : b)
+  // @ts-expect-error Every alternative of a raw-layer replacement must supply A
+  a.replace(flag ? aLayer : Layer.succeed(B, {}))
+  // @ts-expect-error A valid alternative cannot hide a new error in another alternative
+  a.replace(flag ? a : failing)
+  a.replace(flag ? a : ab)
+  failing.replace(flag ? a : failing)
+  // @ts-expect-error Storing replacements must not erase their validation
+  const invalidStored: LayerNode.Replacements = [a.replace(b)]
+  // @ts-expect-error Raw tuples cannot be stored as opaque replacements
+  const rawStored: LayerNode.Replacements = [[a, aLayer]]
+  // @ts-expect-error Raw tuples cannot be supplied to compile
+  LayerNode.compile(a, { replacements: [[a, aLayer]] })
+  // @ts-expect-error Replacements are not structurally forgeable
+  const forged: LayerNode.Replacement = { source: a, target: a }
+  // @ts-expect-error Groups are not replaceable nodes
+  group.replace(a)
+  // @ts-expect-error Groups cannot be replacement targets
+  a.replace(group)
+  // @ts-expect-error Groups cannot be widened to nodes
+  const groupNode: LayerNode.Node<A | B, never, typeof tags.values.app> = group
+  // @ts-expect-error Graphs are opaque
+  const forgedGraph: LayerNode.Graph<A> = { name: "a" }
 
-class TagA extends Context.Service<TagA, {}>()("test/TagA") {}
-class TagB extends Context.Service<TagB, {}>()("test/TagB") {}
-class TagC extends Context.Service<TagC, {}>()("test/TagC") {}
+  const aContract: LayerNode.Node<A, never, typeof tags.values.app> = a
+  aContract.replace(aLayer)
+  // @ts-expect-error A method cannot be rebound to a declaration with a stronger contract
+  a.replace.call(ab, aLayer)
+  const detached = a.replace
+  // @ts-expect-error Replacement authority requires its checked receiver
+  detached(aLayer)
+  // @ts-expect-error Output narrowing cannot forget B before replacement
+  const narrowedOutput: LayerNode.Node<A, never, typeof tags.values.app> = ab
+  // @ts-expect-error Output widening cannot add B before replacement
+  const widenedOutput: LayerNode.Node<A | B, never, typeof tags.values.app> = a
+  // @ts-expect-error Error widening cannot authorize a new replacement error
+  const widenedError: LayerNode.Node<A, LayerError, typeof tags.values.app> = a
+  // @ts-expect-error Error narrowing cannot forget an existing failure
+  const narrowedError: LayerNode.Node<A, never, typeof tags.values.app> = failing
+  // @ts-expect-error Tag widening cannot authorize replacement across tags
+  const widenedTag: LayerNode.Node<A, never, LayerNode.Tag | undefined> = a
+  const unionTag = LayerNode.unbound(A, tag)
+  // @ts-expect-error Tag narrowing cannot forget a possible tag
+  const narrowedTag: LayerNode.Node<A, never, typeof tags.values.app> = unionTag
 
-const scopedTags = LayerNode.tags({ request: ["global"], global: [] })
-const request = scopedTags.make("request")
-const global = scopedTags.make("global")
-const globalA = global({ service: TagA, layer: Layer.succeed(TagA, TagA.of({})), deps: [] })
-const requestA = request({ service: TagA, layer: Layer.succeed(TagA, TagA.of({})), deps: [] })
-const requestB = request({ service: TagB, layer: Layer.succeed(TagB, TagB.of({})), deps: [] })
-const tagBLayer = Layer.effect(TagB, Effect.as(TagA, TagB.of({})))
-const tagCLayer = Layer.effect(
-  TagC,
-  Effect.gen(function* () {
-    yield* TagA
-    yield* TagB
-    return TagC.of({})
-  }),
-)
+  const outputProjection: LayerNode.Graph<A, never, typeof tags.values.app> = group
+  // @ts-expect-error Graph output projection cannot invent a service
+  const widenedGraph: LayerNode.Graph<A | B, never, typeof tags.values.app> = a
+  // @ts-expect-error A projected Graph has no replacement authority
+  outputProjection.replace(aLayer)
 
-request({ service: TagB, layer: tagBLayer, deps: [globalA] })
-request({ service: TagC, layer: tagCLayer, deps: [globalA, requestB] })
-request({ service: TagC, layer: tagCLayer, deps: [LayerNode.group([globalA, requestB])] })
+  const choice = flag ? a : b
+  // @ts-expect-error Choosing one dependency does not provide both services
+  make({ service: C, layer: cLayer, deps: [choice] })
+  // @ts-expect-error A conditional root promises only outputs present in every alternative
+  LayerNode.compile(LayerNode.group([choice])) satisfies Layer.Layer<A | B>
+  const conditional = make({ name: "conditional", layer: flag ? aLayer : Layer.succeed(B, {}), deps: [] })
+  LayerNode.compile(conditional) satisfies Layer.Layer<never>
+  // @ts-expect-error A conditional implementation does not acquire both branches
+  LayerNode.compile(conditional) satisfies Layer.Layer<A | B>
+  LayerNode.compile(LayerNode.group([flag ? a : ab])) satisfies Layer.Layer<A>
+  const dynamic: Array<typeof a> = []
+  // @ts-expect-error An unbounded array may contain no roots
+  LayerNode.compile(LayerNode.group(dynamic)) satisfies Layer.Layer<A>
 
-// @ts-expect-error Tag configuration can only reference declared tags
-LayerNode.tags({ request: ["missing"], global: [] })
+  const decorated = b.mapLayer((layer) => layer.pipe(Layer.tap(() => Effect.void)))
+  LayerNode.compile(decorated) satisfies Layer.Layer<B>
+  b.replace(decorated)
+  // @ts-expect-error A layer mapper cannot be rebound to a weaker declaration
+  ab.mapLayer.call(a, (layer) => layer)
+  // @ts-expect-error mapLayer cannot add an input requirement
+  b.mapLayer((layer) => layer.pipe(Layer.tap(() => C)))
+  // @ts-expect-error mapLayer cannot grow the error channel
+  b.mapLayer((layer) => layer.pipe(Layer.tap(() => Effect.fail(new OtherError()))))
+  // @ts-expect-error mapLayer cannot drop an output
+  ab.mapLayer(() => aLayer)
+  // @ts-expect-error Unbound declarations have no implementation to map
+  inputA.mapLayer((layer: Layer.Layer<A>) => layer)
 
-// @ts-expect-error An unrelated dependency cannot satisfy TagA
-request({ service: TagB, layer: tagBLayer, deps: [requestB] })
+  const scopedTags = LayerNode.tags({ request: ["global"], global: [] })
+  const request = scopedTags.make("request")
+  const global = scopedTags.make("global")
+  const globalA = global({ service: A, layer: aLayer, deps: [] })
+  const requestA = request({ service: A, layer: aLayer, deps: [] })
+  const requestB = request({ service: B, layer: Layer.succeed(B, {}), deps: [] })
+  request({ service: B, layer: bLayer, deps: [globalA] })
+  request({ service: C, layer: cLayer, deps: [globalA, requestB] })
+  request({ service: C, layer: cLayer, deps: [LayerNode.group([globalA, requestB])] })
+  LayerNode.compile(LayerNode.group([globalA, requestB]), { shared: scopedTags.values.global }) satisfies Layer.Layer<
+    A | B
+  >
+  // @ts-expect-error Tag configuration can only reference declared tags
+  LayerNode.tags({ request: ["missing"], global: [] })
+  // @ts-expect-error Shared tags must be branded
+  LayerNode.compile(globalA, { shared: "global" })
+  // @ts-expect-error Replacement targets must keep the source tag
+  globalA.replace(requestA)
+  // @ts-expect-error Replacement targets must keep the source tag in either direction
+  requestA.replace(globalA)
+  // @ts-expect-error Every alternative must keep the source tag
+  globalA.replace(flag ? globalA : requestA)
+  // @ts-expect-error Providing only A leaves B missing
+  request({ service: C, layer: cLayer, deps: [globalA] })
+  // @ts-expect-error Providing only B leaves A missing
+  request({ service: C, layer: cLayer, deps: [requestB] })
+  // @ts-expect-error Duplicate A providers still leave B missing
+  request({ service: C, layer: cLayer, deps: [globalA, requestA] })
+  // @ts-expect-error A group with only A still leaves B missing
+  request({ service: C, layer: cLayer, deps: [LayerNode.group([globalA])] })
+  // @ts-expect-error Global cannot depend on request
+  global({ service: B, layer: bLayer, deps: [requestA] })
+  // @ts-expect-error Groups preserve their child tags
+  global({ service: B, layer: bLayer, deps: [LayerNode.group([requestA])] })
 
-// @ts-expect-error Providing only TagA leaves TagB missing
-request({ service: TagC, layer: tagCLayer, deps: [globalA] })
+  const globalScopedA = makeGlobalNode({ service: A, layer: aLayer, deps: [] })
+  const locationScopedA = makeLocationNode({ service: A, layer: aLayer, deps: [] })
+  makeGlobalNode({ service: B, layer: bLayer, deps: [globalScopedA] })
+  makeLocationNode({ service: B, layer: bLayer, deps: [globalScopedA] })
+  makeLocationNode({ service: B, layer: bLayer, deps: [locationScopedA] })
+  // @ts-expect-error Global nodes cannot depend on location nodes
+  makeGlobalNode({ service: B, layer: bLayer, deps: [locationScopedA] })
+  // @ts-expect-error B requires A
+  makeLocationNode({ service: B, layer: bLayer, deps: [] })
 
-// @ts-expect-error Providing only TagB leaves TagA missing
-request({ service: TagC, layer: tagCLayer, deps: [requestB] })
+  void [
+    invalidStored,
+    rawStored,
+    forged,
+    groupNode,
+    forgedGraph,
+    narrowedOutput,
+    widenedOutput,
+    widenedError,
+    narrowedError,
+    widenedTag,
+    narrowedTag,
+    widenedGraph,
+  ]
+}
 
-// @ts-expect-error Duplicate TagA providers still leave TagB missing
-request({ service: TagC, layer: tagCLayer, deps: [globalA, requestA] })
-
-// @ts-expect-error A group with only TagA still leaves TagB missing
-request({ service: TagC, layer: tagCLayer, deps: [LayerNode.group([globalA])] })
-
-// @ts-expect-error Global cannot depend on request
-global({ service: TagB, layer: tagBLayer, deps: [requestA] })
-
-// @ts-expect-error Groups preserve their child tags
-global({ service: TagB, layer: tagBLayer, deps: [LayerNode.group([requestA])] })
-
-class ScopedA extends Context.Service<ScopedA, {}>()("test/ScopedA") {}
-class ScopedB extends Context.Service<ScopedB, {}>()("test/ScopedB") {}
-
-const scopedA = Layer.succeed(ScopedA, ScopedA.of({}))
-const scopedB = Layer.effect(ScopedB, Effect.as(ScopedA, ScopedB.of({})))
-const globalScopedA = makeGlobalNode({ service: ScopedA, layer: scopedA, deps: [] })
-const locationScopedA = makeLocationNode({ service: ScopedA, layer: scopedA, deps: [] })
-
-makeGlobalNode({ service: ScopedB, layer: scopedB, deps: [globalScopedA] })
-makeLocationNode({ service: ScopedB, layer: scopedB, deps: [globalScopedA] })
-makeLocationNode({ service: ScopedB, layer: scopedB, deps: [locationScopedA] })
-
-// @ts-expect-error Global nodes cannot depend on location nodes
-makeGlobalNode({ service: ScopedB, layer: scopedB, deps: [locationScopedA] })
-
-// @ts-expect-error ScopedB requires ScopedA
-makeLocationNode({ service: ScopedB, layer: scopedB, deps: [] })
-
-test("type exploration compiles", () => {})
+test("layer node type contracts compile", () => {
+  void contracts
+})

packages/core/test/effect/layer-node/layer-node.test.ts

@@ -1,19 +1,21 @@
 import { describe, expect, test } from "bun:test"
-import { Context, Effect, Layer } from "effect"
+import { Context, Deferred, Duration, Effect, Fiber, Layer, LayerMap, Option } from "effect"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
+import { testEffect } from "../../lib/effect"
 
 class Value extends Context.Service<Value, { readonly value: string }>()("test/LayerNodeValue") {}
 class Greeting extends Context.Service<Greeting, { readonly value: string }>()("test/LayerNodeGreeting") {}
 class Left extends Context.Service<Left, { readonly value: string }>()("test/LayerNodeLeft") {}
 class Right extends Context.Service<Right, { readonly value: string }>()("test/LayerNodeRight") {}
-class Database extends Context.Service<Database, { readonly name: string }>()("test/GraphDatabase") {}
-class Users extends Context.Service<Users, { readonly list: Effect.Effect<string[]> }>()("test/GraphUsers") {}
-class App extends Context.Service<App, { readonly run: Effect.Effect<string[]> }>()("test/GraphApp") {}
+class Memo extends Context.Service<Memo, Layer.MemoMap>()("test/LayerNodeMemo") {}
+class Support extends Context.Service<Support, {}>()("test/LayerNodeSupport") {}
+class Locations extends Context.Service<Locations, LayerMap.LayerMap<string, Value | Right, "failed location">>()(
+  "test/LayerNodeLocations",
+) {}
 
+const it = testEffect(Layer.empty)
 const tags = LayerNode.tags({ app: [] })
 const make = tags.make("app")
-const build = <A, E>(root: LayerNode.Node<A, E, any>, replacements?: readonly LayerNode.Replacement[]) =>
-  LayerNode.compile(root, replacements) as Layer.Layer<A, E>
 const valueLayer = Layer.succeed(Value, Value.of({ value: "production" }))
 const greetingLayer = Layer.effect(
   Greeting,
@@ -23,240 +25,443 @@ const value = make({ service: Value, layer: valueLayer, deps: [] })
 const greeting = make({ service: Greeting, layer: greetingLayer, deps: [value] })
 
 describe("layer node", () => {
-  test("builds an untagged graph", async () => {
-    const value = LayerNode.make({ service: Value, layer: valueLayer, deps: [] })
-    const greeting = LayerNode.make({ service: Greeting, layer: greetingLayer, deps: [value] })
-    const program = Effect.map(Greeting, (item) => item.value).pipe(
-      Effect.provide(LayerNode.compile(LayerNode.group([greeting]))),
+  it.effect("builds an untagged graph", () =>
+    Effect.gen(function* () {
+      const value = LayerNode.make({ service: Value, layer: valueLayer, deps: [] })
+      const greeting = LayerNode.make({ service: Greeting, layer: greetingLayer, deps: [value] })
+      const result = yield* Greeting.pipe(Effect.provide(LayerNode.compile(LayerNode.group([greeting]))))
+      expect(result.value).toBe("hello production")
+    }),
+  )
+
+  it.effect("exposes roots but hides transitive dependencies", () =>
+    Effect.gen(function* () {
+      const context = yield* Layer.build(LayerNode.compile(LayerNode.group([greeting])))
+      expect(Context.get(context, Greeting).value).toBe("hello production")
+      expect(Option.isNone(Context.getOption(context, Value))).toBe(true)
+    }),
+  )
+
+  it.effect("replaces exact declarations, not sibling names or native layer identities", () =>
+    Effect.gen(function* () {
+      const sibling = make({ service: Value, layer: valueLayer, deps: [] })
+      const target = make({ name: "different-name", layer: Layer.succeed(Value, { value: "replaced" }), deps: [] })
+      const left = make({
+        service: Left,
+        layer: Layer.effect(
+          Left,
+          Effect.map(Value, (item) => Left.of({ value: item.value })),
+        ),
+        deps: [value],
+      })
+      const right = make({
+        service: Right,
+        layer: Layer.effect(
+          Right,
+          Effect.map(Value, (item) => Right.of({ value: item.value })),
+        ),
+        deps: [sibling],
+      })
+      const context = yield* Layer.build(
+        LayerNode.compile(LayerNode.group([left, right]), { replacements: [value.replace(target)] }),
+      )
+      expect(Context.get(context, Left).value).toBe("replaced")
+      expect(Context.get(context, Right).value).toBe("production")
+    }),
+  )
+
+  it.effect("requires reachable unbound nodes to be replaced", () =>
+    Effect.gen(function* () {
+      const unbound = LayerNode.unbound(Value, tags.values.app)
+      const root = make({ service: Greeting, layer: greetingLayer, deps: [unbound] })
+      expect(() => LayerNode.compile(root)).toThrow("Unbound layer node: test/LayerNodeValue")
+      const result = yield* Greeting.pipe(
+        Effect.provide(LayerNode.compile(root, { replacements: [unbound.replace(value)] })),
+      )
+      expect(result.value).toBe("hello production")
+    }),
+  )
+
+  it.effect("replaces every use of a declaration with a stored closed-layer replacement", () =>
+    Effect.gen(function* () {
+      const replacements: LayerNode.Replacements = [value.replace(Layer.succeed(Value, { value: "replacement" }))]
+      const right = make({
+        service: Right,
+        layer: Layer.effect(
+          Right,
+          Effect.map(Value, (item) => Right.of({ value: item.value })),
+        ),
+        deps: [value],
+      })
+      const context = yield* Layer.build(LayerNode.compile(LayerNode.group([greeting, right]), { replacements }))
+      expect(Context.get(context, Greeting).value).toBe("hello replacement")
+      expect(Context.get(context, Right).value).toBe("replacement")
+    }),
+  )
+
+  it.effect("uses the last replacement and ignores unreachable unbound defaults and cycles", () =>
+    Effect.gen(function* () {
+      const unbound = LayerNode.unbound(Value, tags.values.app)
+      const unused = make({ service: Value, layer: valueLayer, deps: [] })
+      const result = yield* Greeting.pipe(
+        Effect.provide(
+          LayerNode.compile(greeting, {
+            replacements: [
+              value.replace(unbound),
+              unbound.replace(unused),
+              unused.replace(unbound),
+              value.replace(Layer.succeed(Value, { value: "last" })),
+            ],
+          }),
+        ),
+      )
+      expect(result.value).toBe("hello last")
+    }),
+  )
+
+  it.effect("resolves target chains independently of replacement order and treats self-replacement as identity", () =>
+    Effect.gen(function* () {
+      const middle = make({ service: Value, layer: Layer.succeed(Value, { value: "middle" }), deps: [] })
+      const target = make({ service: Value, layer: Layer.succeed(Value, { value: "target" }), deps: [] })
+      const result = yield* Greeting.pipe(
+        Effect.provide(
+          LayerNode.compile(greeting, {
+            replacements: [target.replace(target), middle.replace(target), value.replace(middle)],
+          }),
+        ),
+      )
+      expect(result.value).toBe("hello target")
+    }),
+  )
+
+  test("rejects reachable replacement and dependency cycles", () => {
+    const other = make({ service: Value, layer: valueLayer, deps: [] })
+    expect(() => LayerNode.compile(greeting, { replacements: [value.replace(other), other.replace(value)] })).toThrow(
+      "Cycle detected in layer graph",
     )
-    expect(await Effect.runPromise(program)).toBe("hello production")
-  })
-
-  test("builds a dependency graph", async () => {
-    const program = Effect.map(Greeting, (item) => item.value).pipe(Effect.provide(build(LayerNode.group([greeting]))))
-    expect(await Effect.runPromise(program)).toBe("hello production")
-  })
-
-  test("exposes roots but hides transitive dependencies", () => {
-    const layer = build(LayerNode.group([greeting]))
-    const check: Layer.Layer<Greeting> = layer
-    void check
-  })
-
-  test("preserves branch-specific implementations across roots", async () => {
-    const firstValue = make({ service: Value, layer: Layer.succeed(Value, Value.of({ value: "first" })), deps: [] })
-    const secondValue = make({ service: Value, layer: Layer.succeed(Value, Value.of({ value: "second" })), deps: [] })
-    const leftLayer = Layer.effect(
-      Left,
-      Effect.map(Value, (item) => Left.of({ value: item.value })),
-    )
-    const rightLayer = Layer.effect(
-      Right,
-      Effect.map(Value, (item) => Right.of({ value: item.value })),
-    )
-    const left = make({ service: Left, layer: leftLayer, deps: [firstValue] })
-    const right = make({ service: Right, layer: rightLayer, deps: [secondValue] })
-    const layer = build(LayerNode.group([left, right]))
-    const program = Effect.gen(function* () {
-      return [(yield* Left).value, (yield* Right).value]
-    }).pipe(Effect.provide(layer))
-    expect(await Effect.runPromise(program)).toEqual(["first", "second"])
-  })
-
-  test("requires unbound nodes to be replaced before compilation", async () => {
-    const unbound = LayerNode.unbound(Value, tags.values.app)
-    const greeting = make({ service: Greeting, layer: greetingLayer, deps: [unbound] })
-    const tree = LayerNode.group([greeting])
-    expect(() => LayerNode.compile(tree)).toThrow("Unbound layer node: test/LayerNodeValue")
-    const layer = LayerNode.compile(tree, [[unbound, value]]) as Layer.Layer<Greeting>
-    const program = Effect.map(Greeting, (item) => item.value).pipe(Effect.provide(layer))
-    expect(await Effect.runPromise(program)).toBe("hello production")
-  })
-
-  test("replaces a node with a closed layer", async () => {
-    const replacement = Layer.succeed(Value, Value.of({ value: "simulation" }))
-    const program = Effect.map(Greeting, (item) => item.value).pipe(
-      Effect.provide(build(LayerNode.group([greeting]), [[value, replacement]])),
-    )
-    expect(await Effect.runPromise(program)).toBe("hello simulation")
-  })
-
-  test("replaces every use of the same layer", async () => {
-    const leftLayer = Layer.effect(
-      Left,
-      Effect.map(Value, (item) => Left.of({ value: item.value })),
-    )
-    const rightLayer = Layer.effect(
-      Right,
-      Effect.map(Value, (item) => Right.of({ value: item.value })),
-    )
-    const left = make({ service: Left, layer: leftLayer, deps: [value] })
-    const right = make({ service: Right, layer: rightLayer, deps: [value] })
-    const replacement = Layer.succeed(Value, Value.of({ value: "replaced" }))
-    const layer = build(LayerNode.group([left, right]), [[value, replacement]])
-    const program = Effect.gen(function* () {
-      return [(yield* Left).value, (yield* Right).value]
-    }).pipe(Effect.provide(layer))
-    expect(await Effect.runPromise(program)).toEqual(["replaced", "replaced"])
-  })
-
-  test("does not acquire an unused replacement", async () => {
-    let acquisitions = 0
-    const other = make({ service: Left, layer: Layer.succeed(Left, Left.of({ value: "other" })), deps: [] })
-    const replacement = Layer.effect(
-      Left,
-      Effect.sync(() => {
-        acquisitions++
-        return Left.of({ value: "replacement" })
-      }),
-    )
-    await Effect.runPromise(
-      Effect.map(Greeting, (item) => item.value).pipe(
-        Effect.provide(build(LayerNode.group([greeting]), [[other, replacement]])),
-      ),
-    )
-    expect(acquisitions).toBe(0)
-  })
-
-  test("replaces a node without acquiring its dependencies", async () => {
-    let acquisitions = 0
-    const dependencyLayer = Layer.effect(
-      Value,
-      Effect.sync(() => {
-        acquisitions++
-        return Value.of({ value: "dependency" })
-      }),
-    )
-    const dependency = make({ service: Value, layer: dependencyLayer, deps: [] })
-    const original = make({ service: Greeting, layer: greetingLayer, deps: [dependency] })
-    const replacement = make({
-      service: Greeting,
-      layer: Layer.succeed(Greeting, Greeting.of({ value: "replacement" })),
-      deps: [],
-    })
-
-    const program = Effect.map(Greeting, (item) => item.value).pipe(
-      Effect.provide(build(LayerNode.group([original]), [[original, replacement]])),
-    )
-
-    expect(await Effect.runPromise(program)).toBe("replacement")
-    expect(acquisitions).toBe(0)
-  })
-
-  test("applies later replacements inside earlier replacement nodes", async () => {
-    const original = make({ service: Greeting, layer: greetingLayer, deps: [value] })
-    const replacement = make({ service: Greeting, layer: greetingLayer, deps: [value] })
-    const program = Effect.map(Greeting, (item) => item.value).pipe(
-      Effect.provide(
-        build(LayerNode.group([original]), [
-          [original, replacement],
-          [value, Layer.succeed(Value, Value.of({ value: "replacement dependency" }))],
-        ]),
-      ),
-    )
-
-    expect(await Effect.runPromise(program)).toBe("hello replacement dependency")
-  })
-
-  test("hoists and compiles tagged graphs", async () => {
-    const tags = LayerNode.tags({ location: ["global"], global: [] })
-    const global = tags.make("global")
-    const location = tags.make("location")
-    const database = global({
-      service: Database,
-      layer: Layer.succeed(Database, Database.of({ name: "Alice" })),
-      deps: [],
-    })
-    const users = location({
-      service: Users,
+    const dependent = make({
+      service: Value,
       layer: Layer.effect(
-        Users,
-        Effect.gen(function* () {
-          const db = yield* Database
-          return Users.of({ list: Effect.succeed([db.name]) })
-        }),
+        Value,
+        Effect.map(Greeting, (item) => Value.of({ value: item.value })),
       ),
-      deps: [database],
+      deps: [greeting],
     })
-    const app = location({
-      service: App,
-      layer: Layer.effect(
-        App,
-        Effect.gen(function* () {
-          const service = yield* Users
-          return App.of({ run: service.list })
-        }),
-      ),
-      deps: [users],
-    })
-
-    const result = LayerNode.hoist(LayerNode.group([app]), tags.values.global)
-    expect(result.node.dependencies[0]?.dependencies[0]?.dependencies[0]).toMatchObject({
-      kind: "group",
-      dependencies: [],
-    })
-    expect(result.hoisted.dependencies).toEqual([database])
-
-    const layer = LayerNode.compile(result.node).pipe(
-      Layer.provide(LayerNode.compile(result.hoisted)),
-    ) as unknown as Layer.Layer<App>
-    const program = Effect.gen(function* () {
-      const app = yield* App
-      return yield* app.run
-    }).pipe(Effect.provide(layer))
-
-    expect(await Effect.runPromise(program)).toEqual(["Alice"])
-  })
-
-  test("rejects conflicting hoisted implementations", () => {
-    const tags = LayerNode.tags({ location: ["global"], global: [] })
-    const global = tags.make("global")
-    const location = tags.make("location")
-    const first = global({
-      service: Database,
-      layer: Layer.succeed(Database, Database.of({ name: "first" })),
-      deps: [],
-    })
-    const second = global({
-      service: Database,
-      layer: Layer.succeed(Database, Database.of({ name: "second" })),
-      deps: [],
-    })
-    const left = location({
-      service: Users,
-      layer: Layer.effect(Users, Effect.as(Database, Users.of({ list: Effect.succeed([]) }))),
-      deps: [first],
-    })
-    const right = location({
-      service: App,
-      layer: Layer.effect(App, Effect.as(Database, App.of({ run: Effect.succeed([]) }))),
-      deps: [second],
-    })
-
-    expect(() => LayerNode.hoist(LayerNode.group([left, right]), tags.values.global)).toThrow(
-      "Tag global has conflicting implementations for test/GraphDatabase",
+    expect(() => LayerNode.compile(greeting, { replacements: [value.replace(dependent)] })).toThrow(
+      "Cycle detected in layer graph",
     )
   })
 
-  test("treats dependency groups as transparent while hoisting", () => {
-    const tags = LayerNode.tags({ location: ["global"], global: [] })
-    const global = tags.make("global")
-    const location = tags.make("location")
-    const database = global({
-      service: Database,
-      layer: Layer.succeed(Database, Database.of({ name: "Alice" })),
-      deps: [],
-    })
-    const users = location({
-      service: Users,
-      layer: Layer.effect(Users, Effect.as(Database, Users.of({ list: Effect.succeed([]) }))),
-      deps: [LayerNode.group([database])],
-    })
-    const result = LayerNode.hoist(LayerNode.group([users]), tags.values.global)
+  it.effect("does not acquire replaced dependencies or unused replacement targets", () =>
+    Effect.gen(function* () {
+      const acquired: string[] = []
+      const dependency = make({
+        service: Value,
+        layer: Layer.effect(
+          Value,
+          Effect.sync(() => {
+            acquired.push("old dependency")
+            return Value.of({ value: "dependency" })
+          }),
+        ),
+        deps: [],
+      })
+      const original = make({ service: Greeting, layer: greetingLayer, deps: [dependency] })
+      const result = yield* Greeting.pipe(
+        Effect.provide(
+          LayerNode.compile(original, {
+            replacements: [
+              original.replace(Layer.succeed(Greeting, { value: "replacement" })),
+              value.replace(
+                Layer.effect(
+                  Value,
+                  Effect.sync(() => {
+                    acquired.push("unused target")
+                    return Value.of({ value: "unused" })
+                  }),
+                ),
+              ),
+            ],
+          }),
+        ),
+      )
+      expect(result.value).toBe("replacement")
+      expect(acquired).toEqual([])
+    }),
+  )
 
-    expect(result.node.dependencies[0]?.dependencies[0]?.dependencies[0]).toMatchObject({
-      kind: "group",
-      dependencies: [],
-    })
+  it.effect("mapLayer preserves dependency wiring and replacement traversal", () =>
+    Effect.gen(function* () {
+      const acquired: string[] = []
+      const decorated = greeting.mapLayer((layer) =>
+        layer.pipe(
+          Layer.tap((context) =>
+            Effect.sync(() => {
+              acquired.push(Context.get(context, Greeting).value)
+            }),
+          ),
+        ),
+      )
+      const result = yield* Greeting.pipe(
+        Effect.provide(
+          LayerNode.compile(greeting, {
+            replacements: [
+              greeting.replace(decorated),
+              value.replace(Layer.succeed(Value, { value: "mapped dependency" })),
+            ],
+          }),
+        ),
+      )
+      expect(result.value).toBe("hello mapped dependency")
+      expect(acquired).toEqual(["hello mapped dependency"])
+    }),
+  )
+
+  it.effect("memoizes shared wiring instead of expanding a diamond into a tree", () =>
+    Effect.gen(function* () {
+      const acquisitions: string[] = []
+      const shared = value.mapLayer((layer) =>
+        layer.pipe(Layer.tap(() => Effect.sync(() => acquisitions.push("shared")))),
+      )
+      const left = make({ name: "left", layer: Layer.empty, deps: [shared] })
+      const right = make({ name: "right", layer: Layer.empty, deps: [shared] })
+      yield* Layer.build(LayerNode.compile(LayerNode.group([left, right])))
+      expect(acquisitions).toEqual(["shared"])
+    }),
+  )
+
+  it.effect("preserves declared memo-service outputs rather than filtering them as build metadata", () =>
+    Effect.gen(function* () {
+      const supplied = yield* Layer.makeMemoMap
+      const memo = make({
+        service: Layer.CurrentMemoMap,
+        layer: Layer.succeed(Layer.CurrentMemoMap, supplied),
+        deps: [],
+      })
+      const observer = make({ service: Memo, layer: Layer.effect(Memo, Layer.CurrentMemoMap), deps: [memo] })
+      expect(yield* Memo.pipe(Effect.provide(LayerNode.compile(observer)))).toBe(supplied)
+    }),
+  )
+
+  it.effect("rejects one implementation wired to different effective dependencies in either memo domain", () =>
+    Effect.gen(function* () {
+      const other = make({ service: Value, layer: Layer.succeed(Value, { value: "other" }), deps: [] })
+      const sibling = make({ service: Greeting, layer: greetingLayer, deps: [other] })
+      const root = LayerNode.group([greeting, sibling])
+      expect(() => LayerNode.compile(root)).toThrow("wired to different dependencies")
+      expect(() => LayerNode.compile(root, { shared: tags.values.app })).toThrow("wired to different dependencies")
+      const result = yield* Greeting.pipe(
+        Effect.provide(LayerNode.compile(root, { replacements: [value.replace(other)] })),
+      )
+      expect(result.value).toBe("hello other")
+    }),
+  )
+
+  it.effect("starts dependencies in parallel and nested group roots in order", () =>
+    Effect.gen(function* () {
+      const valueStarted = yield* Deferred.make<void>()
+      const greetingStarted = yield* Deferred.make<void>()
+      const firstStarted = yield* Deferred.make<void>()
+      const releaseFirst = yield* Deferred.make<void>()
+      const events: string[] = []
+      const value = make({
+        service: Value,
+        layer: Layer.effect(
+          Value,
+          Effect.gen(function* () {
+            yield* Deferred.succeed(valueStarted, undefined)
+            yield* Deferred.await(greetingStarted)
+            return Value.of({ value: "value" })
+          }),
+        ),
+        deps: [],
+      })
+      const greeting = make({
+        service: Greeting,
+        layer: Layer.effect(
+          Greeting,
+          Effect.gen(function* () {
+            yield* Deferred.succeed(greetingStarted, undefined)
+            yield* Deferred.await(valueStarted)
+            return Greeting.of({ value: "greeting" })
+          }),
+        ),
+        deps: [],
+      })
+      const first = make({
+        service: Left,
+        layer: Layer.effect(
+          Left,
+          Effect.gen(function* () {
+            yield* Value
+            yield* Greeting
+            events.push("first started")
+            yield* Deferred.succeed(firstStarted, undefined)
+            yield* Deferred.await(releaseFirst)
+            events.push("first finished")
+            return Left.of({ value: "first" })
+          }),
+        ),
+        deps: [value, greeting],
+      })
+      const second = make({
+        service: Right,
+        layer: Layer.effect(
+          Right,
+          Effect.sync(() => {
+            expect(events).toEqual(["first started", "first finished"])
+            events.push("second started")
+            return Right.of({ value: "second" })
+          }),
+        ),
+        deps: [],
+      })
+      const fiber = yield* Layer.build(LayerNode.compile(LayerNode.group([LayerNode.group([first]), second]))).pipe(
+        Effect.forkChild,
+      )
+      yield* Deferred.await(firstStarted)
+      expect(events).toEqual(["first started"])
+      yield* Deferred.succeed(releaseFirst, undefined)
+      const context = yield* Fiber.join(fiber)
+      expect(events).toEqual(["first started", "first finished", "second started"])
+      expect(Context.get(context, Left).value).toBe("first")
+      expect(Context.get(context, Right).value).toBe("second")
+    }),
+  )
+  ;[false, true].forEach((topLevel) => {
+    it.effect(
+      `LayerMap isolates builds and retains resources ${topLevel ? "with" : "without"} a top-level global owner`,
+      () =>
+        Effect.gen(function* () {
+          const acquired = { global: 0, local: 0, support: 0 }
+          const released: string[] = []
+          const startup: string[] = []
+          yield* Effect.gen(function* () {
+            const memoMap = yield* Layer.makeMemoMap
+            const tags = LayerNode.tags({ location: ["global"], global: [] })
+            const global = tags.make("global")
+            const location = tags.make("location")
+            const support = LayerNode.make({
+              service: Support,
+              layer: Layer.effect(
+                Support,
+                Effect.acquireRelease(
+                  Effect.sync(() => {
+                    acquired.support++
+                    return Support.of({})
+                  }),
+                  () =>
+                    Effect.sync(() => {
+                      released.push("support")
+                    }),
+                ),
+              ),
+              deps: [],
+            })
+            const value = global({
+              service: Value,
+              layer: Layer.effect(
+                Value,
+                Effect.andThen(
+                  Support,
+                  Effect.acquireRelease(
+                    Effect.sync(() => {
+                      startup.push("global")
+                      return Value.of({ value: `global-${++acquired.global}` })
+                    }),
+                    (value) =>
+                      Effect.sync(() => {
+                        released.push(value.value)
+                      }),
+                  ),
+                ),
+              ),
+              deps: [support],
+            })
+            const local = location({
+              service: Greeting,
+              layer: Layer.effect(
+                Greeting,
+                Effect.gen(function* () {
+                  yield* Value
+                  return yield* Effect.acquireRelease(
+                    Effect.sync(() => Greeting.of({ value: `local-${++acquired.local}` })),
+                    (value) =>
+                      Effect.sync(() => {
+                        released.push(value.value)
+                      }),
+                  )
+                }),
+              ),
+              deps: [LayerNode.group([value])],
+            })
+            const root = location({
+              service: Right,
+              layer: Layer.effect(
+                Right,
+                Effect.gen(function* () {
+                  const local = yield* Greeting
+                  if (local.value === "local-2") return yield* Effect.fail("failed location" as const)
+                  return Right.of(local)
+                }),
+              ),
+              deps: [local],
+            })
+            // Every key builds the same compiled Layer, not a new graph per lookup.
+            const compiled = LayerNode.compile(LayerNode.group([value, root]), { shared: tags.values.global })
+            const locations = location({
+              service: Locations,
+              layer: Layer.effect(
+                Locations,
+                Effect.gen(function* () {
+                  startup.push("map")
+                  expect(Option.getOrUndefined(yield* Effect.serviceOption(Layer.CurrentMemoMap))).toBe(memoMap)
+                  return yield* LayerMap.make((_: string) => compiled, { idleTimeToLive: Duration.infinity })
+                }),
+              ),
+              deps: [],
+            })
+            const scope = yield* Effect.scope
+            const context = yield* Layer.buildWithMemoMap(
+              LayerNode.compile(LayerNode.group([locations, ...(topLevel ? [value] : [])]), {
+                shared: tags.values.global,
+              }),
+              memoMap,
+              scope,
+            )
+            expect(startup).toEqual(topLevel ? ["map", "global"] : ["map"])
+            const map = Context.get(context, Locations)
+            const first = yield* map.contextEffect("first").pipe(Effect.scoped)
+            expect(Option.getOrUndefined(Context.getOption(context, Value))).toBe(
+              topLevel ? Context.get(first, Value) : undefined,
+            )
+            expect(Option.isNone(Context.getOption(first, Greeting))).toBe(true)
+            expect(Context.get(first, Right).value).toBe("local-1")
+
+            expect(yield* map.contextEffect("failed").pipe(Effect.scoped, Effect.flip)).toBe("failed location")
+            expect(released).toEqual(["local-2"])
+            expect(Context.get(yield* map.contextEffect("first").pipe(Effect.scoped), Right)).toBe(
+              Context.get(first, Right),
+            )
+
+            const second = yield* map.contextEffect("second").pipe(Effect.scoped)
+            expect(Context.get(second, Value)).toBe(Context.get(first, Value))
+            expect(Context.get(second, Right)).not.toBe(Context.get(first, Right))
+            expect(acquired).toEqual({ global: 1, local: 3, support: 1 })
+
+            yield* map.invalidate("first")
+            expect(released).toEqual(["local-2", "local-1"])
+            expect(Context.get(yield* map.contextEffect("second").pipe(Effect.scoped), Right)).toBe(
+              Context.get(second, Right),
+            )
+            const rebuilt = yield* map.contextEffect("first").pipe(Effect.scoped)
+            expect(Context.get(rebuilt, Right).value).toBe("local-4")
+            expect(Context.get(rebuilt, Value)).toBe(Context.get(first, Value))
+            expect(acquired).toEqual({ global: 1, local: 4, support: 1 })
+            expect(released).not.toContain("global-1")
+          }).pipe(Effect.scoped)
+          expect(released.toSorted()).toEqual(["global-1", "local-1", "local-2", "local-3", "local-4", "support"])
+        }),
+    )
   })
 })

packages/core/test/effect/layer-node/node-build.test.ts

@@ -1,20 +1,23 @@
 import { describe, expect, test } from "bun:test"
-import { Context, Effect, Layer, LayerMap, Option } from "effect"
+import { Context, Effect, Layer, Option } from "effect"
 import { Node } from "@opencode-ai/util/effect/app-node"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
 import { Location } from "@opencode-ai/core/location"
 import { LocationServiceMap } from "@opencode-ai/core/location-service-map"
-import type { LocationError, LocationServices } from "@opencode-ai/core/location-services"
+import { buildLocationServiceMap } from "@opencode-ai/core/location-services"
 import { Project } from "@opencode-ai/core/project"
 import { AbsolutePath } from "@opencode-ai/core/schema"
 import { tmpdir } from "../../fixture/tmpdir"
+import { testEffect } from "../../lib/effect"
 
 class Value extends Context.Service<Value, { readonly value: string }>()("test/TagValue") {}
 class Result extends Context.Service<Result, { readonly value: string }>()("test/TagResult") {}
 class CycleA extends Context.Service<CycleA, {}>()("test/NodeBuildA") {}
 class CycleB extends Context.Service<CycleB, { readonly directory: AbsolutePath }>()("test/NodeBuildB") {}
 
+const it = testEffect(Layer.empty)
+
 describe("node build", () => {
   test("does not build a location service map when the graph does not require it", async () => {
     const result = Node.makeGlobalNode({
@@ -31,7 +34,7 @@ describe("node build", () => {
     expect(await Effect.runPromise(program)).toBe("plain")
   })
 
-  test("detects cycles through a replaced location service map", async () => {
+  test("detects cycles through a replaced location service map", () => {
     const a = Node.makeGlobalNode({
       service: CycleA,
       layer: Layer.effect(CycleA, Effect.as(LocationServiceMap.Service, CycleA.of({}))),
@@ -45,31 +48,49 @@ describe("node build", () => {
       ),
       deps: [a],
     })
-    const mapLayer = Layer.effect(
-      LocationServiceMap.Service,
-      Effect.gen(function* () {
-        const service = yield* CycleB
-        return yield* LayerMap.make(
-          (ref: Location.Ref) =>
-            Layer.succeed(
-              Location.Service,
-              Location.Service.of({
-                directory: ref.directory,
-                workspaceID: ref.workspaceID,
-                project: { id: Project.ID.global, directory: service.directory, canonical: service.directory },
-              }),
-            ),
-          { idleTimeToLive: "1 minute" },
-        )
-      }) as unknown as Effect.Effect<LayerMap.LayerMap<Location.Ref, LocationServices, LocationError>, never, CycleB>,
-    )
+    const mapLayer = Layer.unwrap(Effect.as(CycleB, buildLocationServiceMap()))
     const map = Node.makeGlobalNode({ service: LocationServiceMap.Service, layer: mapLayer, deps: [b] })
-    expect(() => AppNodeBuilder.build(LayerNode.group([a]), [[LocationServiceMap.node, map]])).toThrow(
-      "Cycle detected in layer tree",
+    expect(() => AppNodeBuilder.build(LayerNode.group([a]), [LocationServiceMap.node.replace(map)])).toThrow(
+      "Cycle detected in layer graph",
     )
   })
 
-  test("shares top-level project with location services", async () => {
+  it.effect("supplies the lazy map when only a replacement introduces the dependency", () =>
+    Effect.gen(function* () {
+      const original = Node.makeGlobalNode({
+        service: Result,
+        layer: Layer.succeed(Result, { value: "original" }),
+        deps: [],
+      })
+      const replacement = Node.makeGlobalNode({
+        service: Result,
+        layer: Layer.effect(Result, Effect.as(LocationServiceMap.Service, Result.of({ value: "has map" }))),
+        deps: [LocationServiceMap.node],
+      })
+      const result = yield* Result.pipe(Effect.provide(AppNodeBuilder.build(original, [original.replace(replacement)])))
+      expect(result.value).toBe("has map")
+    }),
+  )
+
+  it.effect("caller replacements override the lazy default without building any locations", () =>
+    Effect.gen(function* () {
+      const acquisitions: string[] = []
+      const override = buildLocationServiceMap().pipe(
+        Layer.tap(() =>
+          Effect.sync(() => {
+            acquisitions.push("caller map")
+          }),
+        ),
+      )
+      const context = yield* Layer.build(
+        AppNodeBuilder.build(LocationServiceMap.node, [LocationServiceMap.node.replace(override)]),
+      )
+      expect(Context.get(context, LocationServiceMap.Service)).toBeDefined()
+      expect(acquisitions).toEqual(["caller map"])
+    }),
+  )
+
+  test("shares top-level project even when the location service map is built first", async () => {
     await using tmp = await tmpdir()
     let acquisitions = 0
     const projectLayer = Layer.effect(
@@ -84,8 +105,8 @@ describe("node build", () => {
       }),
     )
     const ref = Location.Ref.make({ directory: AbsolutePath.make(tmp.path) })
-    const layer = AppNodeBuilder.build(LayerNode.group([Project.node, LocationServiceMap.node]), [
-      [Project.node, projectLayer],
+    const layer = AppNodeBuilder.build(LayerNode.group([LocationServiceMap.node, Project.node]), [
+      Project.node.replace(projectLayer),
     ])
     const program = Effect.gen(function* () {
       yield* Project.Service

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

@@ -21,8 +21,8 @@ function provide(directory: string, transformFiles: EnvironmentFilesTransform =
   )
   return Effect.provide(
     AppNodeBuilder.build(LayerNode.group([LocationMutation.node, FileMutation.node]), [
-      [Location.node, activeLocation],
-      [Environment.node, transformEnvironmentFiles(transformFiles)],
+      Location.node.replace(activeLocation),
+      Environment.node.replace(transformEnvironmentFiles(transformFiles)),
     ]),
   )
 }

packages/core/test/filesystem/search.test.ts

@@ -77,16 +77,15 @@ describe("FileSystemSearch", () => {
         workspaceID: Workspace.ID.make("wrk_test"),
       })
       const layer = AppNodeBuilder.build(FileSystemSearch.node, [
-        [
-          Location.node,
+        Location.node.replace(
           Layer.succeed(
             Location.Service,
             Location.Service.of(
               location(ref, { vcs: { type: "git", store: AbsolutePath.make(path.join(directory, ".git")) } }),
             ),
           ),
-        ],
-        [Ripgrep.node, ripgrepStub("remote.ts", (input) => (observed = input))],
+        ),
+        Ripgrep.node.replace(ripgrepStub("remote.ts", (input) => (observed = input))),
       ])
 
       yield* Effect.gen(function* () {
@@ -103,8 +102,7 @@ describe("FileSystemSearch", () => {
       let observed: Ripgrep.FindInput | undefined
       const home = AbsolutePath.make(os.homedir())
       const layer = AppNodeBuilder.build(FileSystemSearch.node, [
-        [
-          Location.node,
+        Location.node.replace(
           Layer.succeed(
             Location.Service,
             Location.Service.of(
@@ -114,8 +112,8 @@ describe("FileSystemSearch", () => {
               ),
             ),
           ),
-        ],
-        [Ripgrep.node, ripgrepStub("src/index.ts", (input) => (observed = input))],
+        ),
+        Ripgrep.node.replace(ripgrepStub("src/index.ts", (input) => (observed = input))),
       ])
       yield* Effect.gen(function* () {
         const search = yield* FileSystemSearch.Service
@@ -137,17 +135,15 @@ describe("FileSystemSearch", () => {
       const started = yield* Deferred.make<void>()
       const release = yield* Deferred.make<void>()
       const layer = AppNodeBuilder.build(FileSystemSearch.node, [
-        [
-          Location.node,
+        Location.node.replace(
           Layer.succeed(
             Location.Service,
             Location.Service.of(
               location({ directory: AbsolutePath.make(path.join(os.tmpdir(), "opencode-search-atomic")) }),
             ),
           ),
-        ],
-        [
-          Ripgrep.node,
+        ),
+        Ripgrep.node.replace(
           Layer.succeed(
             Ripgrep.Service,
             Ripgrep.Service.of({
@@ -169,7 +165,7 @@ describe("FileSystemSearch", () => {
               grep: () => Effect.succeed([]),
             }),
           ),
-        ],
+        ),
       ])
 
       yield* Effect.gen(function* () {
@@ -208,17 +204,15 @@ describe("FileSystemSearch", () => {
         (value) => Effect.sync(() => value.mockRestore()),
       )
       const layer = AppNodeBuilder.build(FileSystemSearch.node, [
-        [
-          Location.node,
+        Location.node.replace(
           Layer.succeed(
             Location.Service,
             Location.Service.of(
               location({ directory: AbsolutePath.make(path.join(os.tmpdir(), "opencode-search-cache")) }),
             ),
           ),
-        ],
-        [
-          Ripgrep.node,
+        ),
+        Ripgrep.node.replace(
           Layer.succeed(
             Ripgrep.Service,
             Ripgrep.Service.of({
@@ -234,7 +228,7 @@ describe("FileSystemSearch", () => {
               grep: () => Effect.succeed([]),
             }),
           ),
-        ],
+        ),
       ])
 
       yield* Effect.gen(function* () {

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

@@ -6,7 +6,7 @@ import { Deferred, Duration, Effect, Fiber, Layer, Option, Schedule, Stream } fr
 import { Config } from "@opencode-ai/core/config"
 import { ConfigLocationWatcherPlugin } from "@opencode-ai/core/config/plugin/location-watcher"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
-import { makeLocationNode, type LocationNode } from "@opencode-ai/util/effect/app-node"
+import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
 import { Bus } from "@opencode-ai/core/bus"
 import { FSUtil } from "@opencode-ai/util/fs-util"
@@ -129,7 +129,7 @@ function provide(
   vcs?: Location.Interface["vcs"],
   watcher?: Layer.Layer<Watcher.Service>,
   config: Layer.Layer<Config.Service> = configLayer,
-  plugins: LocationNode<PluginSupervisor.Service> = pluginNode,
+  plugins: typeof pluginNode = pluginNode,
 ) {
   const locationLayer = Layer.succeed(
     Location.Service,
@@ -138,10 +138,10 @@ function provide(
   const built = AppNodeBuilder.build(
     LayerNode.group([LocationWatcher.node, LocationWatcherPolicy.node, Bus.node, Config.node]),
     [
-      [Config.node, config],
-      [Location.node, locationLayer],
-      [PluginSupervisor.node, plugins],
-      ...(watcher ? ([[Watcher.node, watcher]] as const) : []),
+      Config.node.replace(config),
+      Location.node.replace(locationLayer),
+      PluginSupervisor.node.replace(plugins),
+      ...(watcher ? ([Watcher.node.replace(watcher)] as const) : []),
     ],
   )
   return Effect.provide(built)
@@ -154,7 +154,7 @@ function withTmp<A, E, R>(
     init?: (directory: string) => Promise<void>
     watcher?: Layer.Layer<Watcher.Service>
     config?: Layer.Layer<Config.Service>
-    plugins?: LocationNode<PluginSupervisor.Service>
+    plugins?: typeof pluginNode
   },
 ) {
   return Effect.acquireRelease(

packages/core/test/fixture/effect-flock-worker.ts

@@ -30,7 +30,7 @@ const testGlobal = Global.layerWith({
   log: os.tmpdir(),
 })
 
-const testLayer = LayerNode.compile(EffectFlock.node, [[Global.node, testGlobal]])
+const testLayer = LayerNode.compile(EffectFlock.node, { replacements: [Global.node.replace(testGlobal)] })
 
 async function job() {
   if (msg.ready) await fs.writeFile(msg.ready, String(process.pid))

packages/core/test/fixture/prompt-location.ts

@@ -25,9 +25,9 @@ export const promptLocationNode = makeGlobalNode({
           SessionPrompt.layer.pipe(
             Layer.provideMerge(
               Layer.mergeAll(
-                LayerNode.compile(LayerNode.group([PluginHooks.node, Image.node, Skill.node]), [
-                  [Bus.node, Layer.succeed(Bus.Service, bus)],
-                ]),
+                LayerNode.compile(LayerNode.group([PluginHooks.node, Image.node, Skill.node]), {
+                  replacements: [Bus.node.replace(Layer.succeed(Bus.Service, bus))],
+                }),
                 Layer.succeed(FSUtil.Service, fs),
                 Layer.succeed(PluginSupervisor.Service, { flush: Effect.void }),
               ),

packages/core/test/formatter.test.ts

@@ -20,7 +20,7 @@ import { testEffect } from "./lib/effect"
 
 const it = testEffect(
   AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, SdkPlugins.node, LocationServiceMap.node]), [
-    [Global.node, tempGlobalLayer],
+    Global.node.replace(tempGlobalLayer),
   ]),
 )
 type ConfigInput = typeof Info.Encoded

packages/core/test/instance-plugins.test.ts

@@ -34,7 +34,7 @@ const instances = Layer.effect(
     (ref: Location.Ref) =>
       Instance.layer(ref, {
         plugins: path.basename(ref.directory) === "thread-a" ? [agentPlugin("thread-a-plugin", "thread-a-agent")] : [],
-        replacements: [[Global.node, tempGlobalLayer]],
+        replacements: [Global.node.replace(tempGlobalLayer)],
       }),
     { idleTimeToLive: Duration.infinity },
   ),
@@ -42,8 +42,8 @@ const instances = Layer.effect(
 
 const it = testEffect(
   AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, SdkPlugins.node, LocationServiceMap.node]), [
-    [Global.node, tempGlobalLayer],
-    [LocationServiceMap.node, instances],
+    Global.node.replace(tempGlobalLayer),
+    LocationServiceMap.node.replace(instances),
   ]),
 )
 

packages/core/test/instance-vanilla.test.ts

@@ -23,14 +23,13 @@ import { Bus } from "../src/bus"
 // Config the host hands the vanilla instance explicitly: a value and an
 // explicit plugin removal, both of which must survive discovery: false.
 const hostConfig: LayerNode.Replacements = [
-  [
-    Config.node,
+  Config.node.replace(
     Config.configured({
       project: false,
       global: false,
       content: JSON.stringify({ shell: "vanilla-host", plugins: ["-opencode.tool.shell"] }),
     }),
-  ],
+  ),
 ]
 
 // Same directory contents, two instances: one vanilla, one with discovery.
@@ -43,7 +42,7 @@ const instances = Layer.effect(
         // "bare" exercises the vanilla defaults themselves: no caller Config.
         discovery: name !== "vanilla" && name !== "bare",
         // Caller replacements win over the vanilla defaults.
-        replacements: [[Global.node, tempGlobalLayer], ...(name === "vanilla" ? hostConfig : [])],
+        replacements: [Global.node.replace(tempGlobalLayer), ...(name === "vanilla" ? hostConfig : [])],
       })
     },
     { idleTimeToLive: Duration.infinity },
@@ -52,8 +51,8 @@ const instances = Layer.effect(
 
 const it = testEffect(
   AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, SdkPlugins.node, LocationServiceMap.node]), [
-    [Global.node, tempGlobalLayer],
-    [LocationServiceMap.node, instances],
+    Global.node.replace(tempGlobalLayer),
+    LocationServiceMap.node.replace(instances),
   ]),
 )
 

packages/core/test/instruction-discovery.test.ts

@@ -33,19 +33,18 @@ const instructionLayer = (input: {
     AppNodeBuilder.build(
       LayerNode.group([InstructionDiscovery.node, Bus.node, FSUtil.node, Global.node, Location.node, Watcher.node]),
       [
-        [InstructionDiscovery.node, InstructionDiscovery.configured({ project: input.project })],
-        [
-          Global.node,
+        InstructionDiscovery.node.replace(InstructionDiscovery.configured({ project: input.project })),
+        Global.node.replace(
           input.config || input.home
             ? Global.layerWith({
                 ...(input.config ? { config: input.config } : {}),
                 ...(input.home ? { home: input.home } : {}),
               })
             : tempGlobalLayer,
-        ],
-        [Location.node, input.locationServiceLayer],
-        [Watcher.node, watcher],
-        ...(input.filesystemLayer ? [[FSUtil.node, input.filesystemLayer] as const] : []),
+        ),
+        Location.node.replace(input.locationServiceLayer),
+        Watcher.node.replace(watcher),
+        ...(input.filesystemLayer ? [FSUtil.node.replace(input.filesystemLayer)] : []),
       ],
     ),
     watcher,

packages/core/test/instruction-state.test.ts

@@ -24,7 +24,7 @@ import { testEffect } from "./lib/effect"
 
 const it = testEffect(
   AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, SessionProjector.node]), [
-    [Bus.node, Bus.configured({ persist: true })],
+    Bus.node.replace(Bus.configured({ persist: true })),
   ]),
 )
 

packages/core/test/instructions/builtins.test.ts

@@ -30,8 +30,8 @@ const locationLayer = Layer.succeed(
 )
 const it = testEffect(
   AppNodeBuilder.build(InstructionBuiltIns.node, [
-    [Location.node, locationLayer],
-    [Global.node, Global.layerWith({ config: temporary, tmp: temporary })],
+    Location.node.replace(locationLayer),
+    Global.node.replace(Global.layerWith({ config: temporary, tmp: temporary })),
   ]),
 )
 

packages/core/test/integration.test.ts

@@ -27,7 +27,7 @@ const failingCredentialNode = makeGlobalNode({
   deps: [],
 })
 const failingIt = testEffect(
-  AppNodeBuilder.build(LayerNode.group([Integration.node, Bus.node]), [[Credential.node, failingCredentialNode]]),
+  AppNodeBuilder.build(LayerNode.group([Integration.node, Bus.node]), [Credential.node.replace(failingCredentialNode)]),
 )
 
 function eventually<A, E, R>(

packages/core/test/location-filesystem.test.ts

@@ -13,15 +13,16 @@ import { it } from "./lib/effect"
 
 const provide = (directory: string, workspaceID?: Workspace.ID) =>
   Effect.provide(
-    LayerNode.compile(FileSystem.node, [
-      [
-        Location.node,
-        Layer.succeed(
-          Location.Service,
-          Location.Service.of(location({ directory: AbsolutePath.make(directory), workspaceID })),
+    LayerNode.compile(FileSystem.node, {
+      replacements: [
+        Location.node.replace(
+          Layer.succeed(
+            Location.Service,
+            Location.Service.of(location({ directory: AbsolutePath.make(directory), workspaceID })),
+          ),
         ),
       ],
-    ]),
+    }),
   )
 
 const withTmp = <A, E, R>(f: (directory: string) => Effect.Effect<A, E, R>) =>

packages/core/test/location-layer.test.ts

@@ -51,12 +51,12 @@ import { Tool } from "../src/tool"
 
 const it = testEffect(
   AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, LocationServiceMap.node]), [
-    [Global.node, tempGlobalLayer],
+    Global.node.replace(tempGlobalLayer),
   ]),
 )
 const itWithSdk = testEffect(
   AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, SdkPlugins.node, LocationServiceMap.node]), [
-    [Global.node, tempGlobalLayer],
+    Global.node.replace(tempGlobalLayer),
   ]),
 )
 const activityLocations = Layer.effect(
@@ -77,7 +77,7 @@ const activityLocations = Layer.effect(
 )
 const itWithActivity = testEffect(
   AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, LocationServiceMap.node, LocationActivity.node]), [
-    [LocationServiceMap.node, activityLocations],
+    LocationServiceMap.node.replace(activityLocations),
   ]),
 )
 

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

@@ -13,20 +13,21 @@ import { it } from "./lib/effect"
 
 function provide(directory: string, projectDirectory = directory) {
   return Effect.provide(
-    LayerNode.compile(LocationMutation.node, [
-      [
-        Location.node,
-        Layer.succeed(
-          Location.Service,
-          Location.Service.of(
-            location(
-              { directory: AbsolutePath.make(directory) },
-              { projectDirectory: AbsolutePath.make(projectDirectory) },
+    LayerNode.compile(LocationMutation.node, {
+      replacements: [
+        Location.node.replace(
+          Layer.succeed(
+            Location.Service,
+            Location.Service.of(
+              location(
+                { directory: AbsolutePath.make(directory) },
+                { projectDirectory: AbsolutePath.make(projectDirectory) },
+              ),
             ),
           ),
         ),
       ],
-    ]),
+    }),
   )
 }
 

packages/core/test/location.test.ts

@@ -23,7 +23,7 @@ const projectLayer = Layer.succeed(
       }),
   }),
 )
-const it = testEffect(AppNodeBuilder.build(Location.boundNode(ref), [[Project.node, projectLayer]]))
+const it = testEffect(AppNodeBuilder.build(Location.boundNode(ref), [Project.node.replace(projectLayer)]))
 
 describe("Location", () => {
   it.effect("resolves the current project and vcs information", () =>

packages/core/test/mcp-instructions.test.ts

@@ -23,13 +23,12 @@ const tool = (server: string, name = "search") => new Mcp.Tool({ server: Mcp.Ser
 
 const layer = (catalog: () => Mcp.ServerInstructions[], tools: () => Mcp.Tool[]) =>
   AppNodeBuilder.build(McpInstructions.node, [
-    [
-      Mcp.node,
+    Mcp.node.replace(
       Layer.mock(Mcp.Service, {
         instructions: () => Effect.succeed(catalog()),
         tools: () => Effect.succeed(tools()),
       }),
-    ],
+    ),
   ])
 
 describe("McpInstructions", () => {

packages/core/test/mcp.test.ts

@@ -376,10 +376,10 @@ const permissions = Layer.mock(Permission.Service, {
 const events = Layer.mock(Bus.Service, { subscribe: () => Stream.never })
 const it = testEffect(
   AppNodeBuilder.build(LayerNode.group([Tool.node, McpTool.node]), [
-    [Mcp.node, mcp],
-    [Permission.node, permissions],
-    [Bus.node, events],
-    [Image.node, imagePassthrough],
+    Mcp.node.replace(mcp),
+    Permission.node.replace(permissions),
+    Bus.node.replace(events),
+    Image.node.replace(imagePassthrough),
   ]),
 )
 
@@ -1645,8 +1645,7 @@ testEffect(Layer.empty).live("isolates invalid MCP tools and preserves plugin tr
       Effect.provide(
         Layer.fresh(
           AppNodeBuilder.build(LayerNode.group([Tool.node, McpTool.node, Bus.node]), [
-            [
-              Mcp.node,
+            Mcp.node.replace(
               Layer.mock(Mcp.Service, {
                 tools: () => Ref.get(catalog),
                 callTool: (input) =>
@@ -1659,9 +1658,9 @@ testEffect(Layer.empty).live("isolates invalid MCP tools and preserves plugin tr
                     }),
                   ),
               }),
-            ],
-            [Permission.node, Layer.mock(Permission.Service, { assert: () => Effect.void })],
-            [Image.node, imagePassthrough],
+            ),
+            Permission.node.replace(Layer.mock(Permission.Service, { assert: () => Effect.void })),
+            Image.node.replace(imagePassthrough),
           ]),
         ),
       ),
@@ -1688,8 +1687,7 @@ testEffect(Layer.empty).effect("coalesces queued MCP tool notifications after in
   }).pipe(
     Effect.provide(
       AppNodeBuilder.build(LayerNode.group([Tool.node, McpTool.node, Bus.node]), [
-        [
-          Mcp.node,
+        Mcp.node.replace(
           Layer.mock(Mcp.Service, {
             tools: () =>
               Effect.sync(() => [
@@ -1701,9 +1699,9 @@ testEffect(Layer.empty).effect("coalesces queued MCP tool notifications after in
                 }),
               ]),
           }),
-        ],
-        [Permission.node, Layer.mock(Permission.Service, { assert: () => Effect.void })],
-        [Image.node, imagePassthrough],
+        ),
+        Permission.node.replace(Layer.mock(Permission.Service, { assert: () => Effect.void })),
+        Image.node.replace(imagePassthrough),
       ]),
     ),
   )

packages/core/test/models.test.ts

@@ -182,9 +182,9 @@ const buildLayer = (state: Ref.Ref<MockState>, cache: MockCache, options: Models
   // every test would reuse the cachedInvalidateWithTTL state from the first run.
   Layer.fresh(
     AppNodeBuilder.build(LayerNode.group([ModelsDev.node, Bus.node]), [
-      [ModelsDev.node, ModelsDev.configured(options)],
-      [LayerNodePlatform.httpClient, Layer.succeed(HttpClient.HttpClient, makeMockClient(state))],
-      [KV.node, makeMockKV(cache)],
+      ModelsDev.node.replace(ModelsDev.configured(options)),
+      LayerNodePlatform.httpClient.replace(Layer.succeed(HttpClient.HttpClient, makeMockClient(state))),
+      KV.node.replace(makeMockKV(cache)),
     ]),
   )
 
@@ -312,9 +312,9 @@ describe("ModelsDev Service", () => {
       const state = yield* Ref.make({ ...initialState, body: JSON.stringify(fixture2) })
       const layer = Layer.fresh(
         AppNodeBuilder.build(ModelsDev.node, [
-          [ModelsDev.node, ModelsDev.configured({ fetch: true, snapshot: false })],
-          [LayerNodePlatform.httpClient, Layer.succeed(HttpClient.HttpClient, makeMockClient(state))],
-          [KV.node, makeFailingWriteKV(cache)],
+          ModelsDev.node.replace(ModelsDev.configured({ fetch: true, snapshot: false })),
+          LayerNodePlatform.httpClient.replace(Layer.succeed(HttpClient.HttpClient, makeMockClient(state))),
+          KV.node.replace(makeFailingWriteKV(cache)),
         ]),
       )
       const result = yield* ModelsDev.Service.use((s) => s.get()).pipe(Effect.provide(layer))

packages/core/test/npm.test.ts

@@ -20,7 +20,7 @@ const writePackage = (dir: string, pkg: Record<string, unknown>) =>
   )
 
 const npmLayer = (cache: string) =>
-  AppNodeBuilder.build(Npm.node, [[Global.node, Global.layerWith({ cache, state: path.join(cache, "state") })]])
+  AppNodeBuilder.build(Npm.node, [Global.node.replace(Global.layerWith({ cache, state: path.join(cache, "state") }))])
 
 async function createGitFixture(directory: string) {
   const repository = path.join(directory, "repository")

packages/core/test/permission.test.ts

@@ -37,7 +37,7 @@ const it = testEffect(
       PluginHooks.node,
       Permission.node,
     ]),
-    [[Location.node, current]],
+    [Location.node.replace(current)],
   ),
 )
 

packages/core/test/plugin-hooks.test.ts

@@ -4,12 +4,12 @@ import { Agent } from "@opencode-ai/schema/agent"
 import { Model } from "@opencode-ai/schema/model"
 import { Provider } from "@opencode-ai/schema/provider"
 import { Session } from "@opencode-ai/schema/session"
-import { Effect, Layer } from "effect"
+import { LayerNode } from "@opencode-ai/util/effect/layer-node"
+import { Effect } from "effect"
 import { PluginHooks } from "../src/plugin/hooks"
 import { testEffect } from "./lib/effect"
 
-const layer = PluginHooks.node.implementation as Layer.Layer<PluginHooks.Service>
-const it = testEffect(layer)
+const it = testEffect(LayerNode.compile(PluginHooks.node))
 
 describe("PluginHooks", () => {
   it.effect("registers scoped session hooks and triggers them sequentially", () =>

packages/core/test/plugin/command.test.ts

@@ -27,8 +27,8 @@ const locationLayer = Layer.succeed(
 )
 const it = testEffect(
   AppNodeBuilder.build(LayerNode.group([Command.node, Mcp.node, Bus.node]), [
-    [Mcp.node, emptyMcpLayer],
-    [Location.node, locationLayer],
+    Mcp.node.replace(emptyMcpLayer),
+    Location.node.replace(locationLayer),
   ]),
 )
 

packages/core/test/plugin/fixture.ts

@@ -86,12 +86,14 @@ export const PluginTestLayer = LayerNode.compile(
     Watcher.node,
     WebSearch.node,
   ]),
-  [
-    [Location.node, tempLocationLayer],
-    [Npm.node, npmLayer],
-    [Config.node, Config.testLayer()],
-    [Mcp.node, emptyMcpLayer],
-    [Generate.node, generateLayer],
-    [Permission.node, permissionLayer],
-  ],
+  {
+    replacements: [
+      Location.node.replace(tempLocationLayer),
+      Npm.node.replace(npmLayer),
+      Config.node.replace(Config.testLayer()),
+      Mcp.node.replace(emptyMcpLayer),
+      Generate.node.replace(generateLayer),
+      Permission.node.replace(permissionLayer),
+    ],
+  },
 ) as unknown as Layer.Layer<unknown, never>

packages/core/test/plugin/host.test.ts

@@ -23,11 +23,11 @@ const it = testEffect(
       PluginRuntime.providerNodeWithCell(cell),
     ]),
     [
-      [Global.node, tempGlobalLayer],
-      [Watcher.node, Watcher.configured({ enabled: false })],
-      [SessionExecution.node, SessionExecution.noopLayer],
-      [PluginRuntime.node, PluginRuntime.layerWithCell(cell)],
-      [PersistentPty.node, PersistentPty.configured()],
+      Global.node.replace(tempGlobalLayer),
+      Watcher.node.replace(Watcher.configured({ enabled: false })),
+      SessionExecution.node.replace(SessionExecution.noopLayer),
+      PluginRuntime.node.replace(PluginRuntime.layerWithCell(cell)),
+      PersistentPty.node.replace(PersistentPty.configured()),
     ],
   ),
 )

packages/core/test/plugin/models-dev.test.ts

@@ -27,12 +27,12 @@ const locationLayer = Layer.succeed(
   Location.Service.of(location({ directory: AbsolutePath.make(import.meta.dir) })),
 )
 const layer = AppNodeBuilder.build(LayerNode.group([Catalog.node, Integration.node, Bus.node]), [
-  [Location.node, locationLayer],
+  Location.node.replace(locationLayer),
 ])
 const it = testEffect(layer)
 const real = testEffect(PluginTestLayer)
 const models = (file: string) =>
-  AppNodeBuilder.build(ModelsDev.node, [[ModelsDev.node, ModelsDev.configured({ file, fetch: false })]])
+  AppNodeBuilder.build(ModelsDev.node, [ModelsDev.node.replace(ModelsDev.configured({ file, fetch: false }))])
 
 describe("ModelsDevPlugin", () => {
   real.effect("keeps the retained model seed unchanged across catalog replay", () =>

packages/core/test/plugin/variant.test.ts

@@ -15,7 +15,7 @@ const locationLayer = Layer.succeed(
   Location.Service,
   Location.Service.of(location({ directory: AbsolutePath.make(import.meta.dir) })),
 )
-const it = testEffect(AppNodeBuilder.build(Catalog.node, [[Location.node, locationLayer]]))
+const it = testEffect(AppNodeBuilder.build(Catalog.node, [Location.node.replace(locationLayer)]))
 
 describe("VariantPlugin", () => {
   it.effect("adds GLM 5.2 variants after catalog sources", () =>

packages/core/test/plugin/websearch-fixture.ts

@@ -42,7 +42,7 @@ const http = Layer.succeed(
 export const webSearchIntegrationTest = testEffect(
   Layer.merge(
     AppNodeBuilder.build(LayerNode.group([Integration.node, Credential.node, Bus.node, Form.node, WebSearch.node]), [
-      [Config.node, Config.testLayer()],
+      Config.node.replace(Config.testLayer()),
     ]),
     http,
   ),

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

@@ -17,7 +17,9 @@ const locationLayer = Layer.succeed(
   Location.Service,
   Location.Service.of(location({ directory: AbsolutePath.make("/tmp") })),
 )
-const it = testEffect(AppNodeBuilder.build(LayerNode.group([Pty.node, Bus.node]), [[Location.node, locationLayer]]))
+const it = testEffect(
+  AppNodeBuilder.build(LayerNode.group([Pty.node, Bus.node]), [Location.node.replace(locationLayer)]),
+)
 const ptyTest = process.platform === "win32" ? it.live.skip : it.live
 
 const subscribePtyEvents = Effect.fn("PtySessionTest.subscribePtyEvents")(function* () {
@@ -200,7 +202,7 @@ describe("pty", () => {
 
 const configuredShell = process.platform === "win32" ? undefined : Bun.which("bash")
 const configuredIt = testEffect(
-  AppNodeBuilder.build(LayerNode.group([Pty.node, Bus.node, ShellSelect.node]), [[Location.node, locationLayer]]),
+  AppNodeBuilder.build(LayerNode.group([Pty.node, Bus.node, ShellSelect.node]), [Location.node.replace(locationLayer)]),
 )
 const configuredTest = process.platform === "win32" ? configuredIt.live.skip : configuredIt.live
 

packages/core/test/pty/ticket.test.ts

@@ -8,7 +8,9 @@ import { testEffect } from "../lib/effect"
 
 const it = testEffect(LayerNode.compile(PtyTicket.node))
 const itExpiring = testEffect(
-  LayerNode.compile(PtyTicket.node, [[PtyTicket.node, Layer.effect(PtyTicket.Service, PtyTicket.make(5))]]),
+  LayerNode.compile(PtyTicket.node, {
+    replacements: [PtyTicket.node.replace(Layer.effect(PtyTicket.Service, PtyTicket.make(5)))],
+  }),
 )
 
 describe("PTY websocket tickets", () => {

packages/core/test/reference-instructions.test.ts

@@ -8,7 +8,7 @@ import { it } from "./lib/effect"
 import { readInitial, readUpdate } from "./lib/instructions"
 
 const instructionsLayer = (referenceLayer: Layer.Layer<Reference.Service>) =>
-  AppNodeBuilder.build(ReferenceInstructions.node, [[Reference.node, referenceLayer]])
+  AppNodeBuilder.build(ReferenceInstructions.node, [Reference.node.replace(referenceLayer)])
 
 describe("ReferenceInstructions", () => {
   it.effect("lists available references in the instructions", () =>

packages/core/test/reference.test.ts

@@ -11,7 +11,7 @@ import { it } from "./lib/effect"
 const cache = Layer.mock(RepositoryCache.Service, {
   ensure: () => Effect.die("unexpected Git materialization"),
 })
-const referenceLayer = AppNodeBuilder.build(Reference.node, [[RepositoryCache.node, cache]])
+const referenceLayer = AppNodeBuilder.build(Reference.node, [RepositoryCache.node.replace(cache)])
 
 describe("Reference", () => {
   it.effect("registers normalized sources for the owning scope", () =>

packages/core/test/repository-cache.test.ts

@@ -124,7 +124,7 @@ describe("RepositoryCache", () => {
 
 function cacheLayer(root: string) {
   return AppNodeBuilder.build(RepositoryCache.node, [
-    [Global.node, Global.layerWith({ state: path.join(root, "state"), repos: path.join(root, "repos") })],
+    Global.node.replace(Global.layerWith({ state: path.join(root, "state"), repos: path.join(root, "repos") })),
   ])
 }
 

packages/core/test/ripgrep.test.ts

@@ -10,7 +10,7 @@ import { tmpdir } from "./fixture/tmpdir"
 import { testEffect } from "./lib/effect"
 import { tempLocationLayer } from "./fixture/location"
 
-const it = testEffect(AppNodeBuilder.build(Ripgrep.node, [[Location.node, tempLocationLayer]]))
+const it = testEffect(AppNodeBuilder.build(Ripgrep.node, [Location.node.replace(tempLocationLayer)]))
 
 describe("Ripgrep", () => {
   it.live("globs files as an array", () =>

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

@@ -65,9 +65,9 @@ const it = testEffect(
   AppNodeBuilder.build(
     LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node, Session.node]),
     [
-      [LocationServiceMap.node, locations],
-      [Project.node, globalProjectNode],
-      [SessionExecution.node, SessionExecution.noopLayer],
+      LocationServiceMap.node.replace(locations),
+      Project.node.replace(globalProjectNode),
+      SessionExecution.node.replace(SessionExecution.noopLayer),
     ],
   ),
 )

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

@@ -88,10 +88,7 @@ const it = testEffect(
       SessionCompaction.node,
       SessionModelRequest.node,
     ]),
-    [
-      [Bus.node, Bus.configured({ persist: true })],
-      [llmClient, client],
-    ],
+    [Bus.node.replace(Bus.configured({ persist: true })), llmClient.replace(client)],
   ),
 )
 

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

@@ -51,30 +51,27 @@ const it = testEffect(
       InstructionEntry.node,
     ]),
     [
-      [Bus.node, Bus.configured({ persist: true })],
-      [Project.node, globalProjectNode],
-      [LocationServiceMap.node, promptLocationNode],
-      [SessionExecution.node, SessionExecution.noopLayer],
+      Bus.node.replace(Bus.configured({ persist: true })),
+      Project.node.replace(globalProjectNode),
+      LocationServiceMap.node.replace(promptLocationNode),
+      SessionExecution.node.replace(SessionExecution.noopLayer),
     ],
   ),
 )
 const liveIt = testEffect(
   AppNodeBuilder.build(
     LayerNode.group([Database.node, Bus.node, Project.node, SessionProjector.node, SessionStore.node, Session.node]),
-    [
-      [Bus.node, Bus.configured({ persist: true })],
-      [SessionExecution.node, SessionExecution.noopLayer],
-    ],
+    [Bus.node.replace(Bus.configured({ persist: true })), SessionExecution.node.replace(SessionExecution.noopLayer)],
   ),
 )
 const projectIt = testEffect(
   AppNodeBuilder.build(
     LayerNode.group([Database.node, Bus.node, Project.node, SessionProjector.node, SessionStore.node, Session.node]),
     [
-      [Bus.node, Bus.configured({ persist: true })],
+      Bus.node.replace(Bus.configured({ persist: true })),
       // Project adoption needs plain-prompt admission, not live plugin/provider startup.
-      [LocationServiceMap.node, promptLocationNode],
-      [SessionExecution.node, SessionExecution.noopLayer],
+      LocationServiceMap.node.replace(promptLocationNode),
+      SessionExecution.node.replace(SessionExecution.noopLayer),
     ],
   ),
 )
@@ -968,8 +965,8 @@ describe("Session.create", () => {
       const targetLayer = AppNodeBuilder.build(
         LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node]),
         [
-          [Database.node, Database.configured({ path: path.join(tmp.path, "target.sqlite") })],
-          [Bus.node, Bus.configured({ persist: true })],
+          Database.node.replace(Database.configured({ path: path.join(tmp.path, "target.sqlite") })),
+          Bus.node.replace(Bus.configured({ persist: true })),
         ],
       )
 

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

@@ -142,17 +142,17 @@ const it = testEffect(
       SessionGenerateNode.node,
     ]),
     [
-      [Bus.node, Bus.configured({ persist: true })],
-      [llmClient, client],
-      [SessionRunnerModel.node, models],
-      [InstructionBuiltIns.node, builtins],
-      [InstructionDiscovery.node, discovery],
-      [SkillInstructions.node, skills],
-      [ReferenceInstructions.node, references],
-      [McpInstructions.node, mcp],
-      [PluginSupervisor.node, plugins],
-      [Tool.node, tools],
-      [Location.node, Location.boundNode({ directory: AbsolutePath.make("/project") })],
+      Bus.node.replace(Bus.configured({ persist: true })),
+      llmClient.replace(client),
+      SessionRunnerModel.node.replace(models),
+      InstructionBuiltIns.node.replace(builtins),
+      InstructionDiscovery.node.replace(discovery),
+      SkillInstructions.node.replace(skills),
+      ReferenceInstructions.node.replace(references),
+      McpInstructions.node.replace(mcp),
+      PluginSupervisor.node.replace(plugins),
+      Tool.node.replace(tools),
+      Location.node.replace(Location.boundNode({ directory: AbsolutePath.make("/project") })),
     ],
   ),
 )

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

@@ -53,7 +53,7 @@ const readToolNode = makeLocationNode({
 
 const permission = permissionLayer({ assert: () => Effect.void })
 const config = Config.testLayer()
-const imageLayer = AppNodeBuilder.build(Image.node, [[Config.node, config]])
+const imageLayer = AppNodeBuilder.build(Image.node, [Config.node.replace(config)])
 
 const testLayer = AppNodeBuilder.build(
   LayerNode.group([
@@ -74,12 +74,12 @@ const testLayer = AppNodeBuilder.build(
     Image.node,
   ]),
   [
-    [Project.node, globalProjectNode],
-    [SessionExecution.node, SessionExecution.noopLayer],
-    [Location.node, tempLocationLayer],
-    [Permission.node, permission],
-    [Config.node, config],
-    [Image.node, imageLayer],
+    Project.node.replace(globalProjectNode),
+    SessionExecution.node.replace(SessionExecution.noopLayer),
+    Location.node.replace(tempLocationLayer),
+    Permission.node.replace(permission),
+    Config.node.replace(config),
+    Image.node.replace(imageLayer),
   ],
 )
 

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

@@ -22,9 +22,9 @@ const it = testEffect(
   AppNodeBuilder.build(
     LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node, Session.node]),
     [
-      [Bus.node, Bus.configured({ persist: true })],
-      [Project.node, globalProjectNode],
-      [SessionExecution.node, SessionExecution.noopLayer],
+      Bus.node.replace(Bus.configured({ persist: true })),
+      Project.node.replace(globalProjectNode),
+      SessionExecution.node.replace(SessionExecution.noopLayer),
     ],
   ),
 )

packages/core/test/session-message-update.test.ts

@@ -30,10 +30,9 @@ const it = testEffect(
   AppNodeBuilder.build(
     LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node, Session.node]),
     [
-      [Bus.node, Bus.configured({ persist: true })],
-      [Project.node, globalProjectNode],
-      [
-        SessionExecution.node,
+      Bus.node.replace(Bus.configured({ persist: true })),
+      Project.node.replace(globalProjectNode),
+      SessionExecution.node.replace(
         Layer.succeed(
           SessionExecution.Service,
           SessionExecution.Service.of({
@@ -45,7 +44,7 @@ const it = testEffect(
             awaitIdle: () => Effect.void,
           }),
         ),
-      ],
+      ),
     ],
   ),
 )
@@ -154,8 +153,8 @@ describe("Session.updateMessage", () => {
       const target = AppNodeBuilder.build(
         LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node]),
         [
-          [Database.node, Database.configured({ path: path.join(tmp.path, "target.sqlite") })],
-          [Bus.node, Bus.configured({ persist: true })],
+          Database.node.replace(Database.configured({ path: path.join(tmp.path, "target.sqlite") })),
+          Bus.node.replace(Bus.configured({ persist: true })),
         ],
       )
 

packages/core/test/session-model-request.test.ts

@@ -20,9 +20,13 @@ import { testEffect } from "./lib/effect"
 const capabilities = (input: string[]) => ({ tools: true, input, output: ["text"] })
 
 const it = testEffect(
-  LayerNode.compile(LayerNode.group([SessionModelRequest.node, PluginHooks.node]), [
-    [SessionModelTransport.node, SessionModelTransport.makeLayer({ open: () => Effect.die("Unexpected connection") })],
-  ]),
+  LayerNode.compile(LayerNode.group([SessionModelRequest.node, PluginHooks.node]), {
+    replacements: [
+      SessionModelTransport.node.replace(
+        SessionModelTransport.makeLayer({ open: () => Effect.die("Unexpected connection") }),
+      ),
+    ],
+  }),
 )
 
 const requestInput = (model: LanguageModel) => ({

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

@@ -24,10 +24,7 @@ import { globalProjectNode } from "./lib/project"
 const it = testEffect(
   AppNodeBuilder.build(
     LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node, Session.node]),
-    [
-      [Project.node, globalProjectNode],
-      [SessionExecution.node, SessionExecution.noopLayer],
-    ],
+    [Project.node.replace(globalProjectNode), SessionExecution.node.replace(SessionExecution.noopLayer)],
   ),
 )
 const unavailableLocations = Layer.effect(
@@ -40,9 +37,9 @@ const itWithUnavailableDestination = testEffect(
   AppNodeBuilder.build(
     LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node, Session.node]),
     [
-      [Project.node, globalProjectNode],
-      [SessionExecution.node, SessionExecution.noopLayer],
-      [LocationServiceMap.node, unavailableLocations],
+      Project.node.replace(globalProjectNode),
+      SessionExecution.node.replace(SessionExecution.noopLayer),
+      LocationServiceMap.node.replace(unavailableLocations),
     ],
   ),
 )

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

@@ -49,10 +49,9 @@ const it = testEffect(
       SessionInbox.node,
       FSUtil.node,
     ]),
-    [
-      [Bus.node, Bus.configured({ persist: true })],
-      [Global.node, tempGlobalLayer],
-    ],
+    {
+      replacements: [Bus.node.replace(Bus.configured({ persist: true })), Global.node.replace(tempGlobalLayer)],
+    },
   ),
 )
 const sessionID = SessionSchema.ID.make("ses_owned")

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

@@ -21,7 +21,6 @@ import { SessionProjector } from "@opencode-ai/core/session/projector"
 import { SessionExecution } from "@opencode-ai/core/session/execution"
 import { fromRow } from "@opencode-ai/core/session/info"
 import { SessionInbox } from "@opencode-ai/core/session/inbox"
-import { SessionStore } from "@opencode-ai/core/session/store"
 import { Shell } from "@opencode-ai/schema/shell"
 import {
   InstructionStateTable,
@@ -33,12 +32,11 @@ import { testEffect } from "./lib/effect"
 import { Snapshot } from "@opencode-ai/core/snapshot"
 
 const it = testEffect(
-  AppNodeBuilder.build(
-    LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionInbox.node, SessionStore.node]),
-    [[Bus.node, Bus.configured({ persist: true })]],
-  ),
+  AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionInbox.node]), [
+    Bus.node.replace(Bus.configured({ persist: true })),
+  ]),
 )
-const sessionsLayer = AppNodeBuilder.build(Session.node, [[SessionExecution.node, SessionExecution.noopLayer]])
+const sessionsLayer = AppNodeBuilder.build(Session.node, [SessionExecution.node.replace(SessionExecution.noopLayer)])
 const sessionID = Session.ID.make("ses_projector_test")
 const created = DateTime.makeUnsafe(0)
 const model = { id: Model.ID.make("model"), providerID: Provider.ID.make("provider") }
@@ -280,9 +278,7 @@ describe("SessionProjector", () => {
       yield* db.run(sql`update session_message set data = '{"time":{"created":0}}' where id = ${messageID}`)
 
       const sessions = yield* Session.Service
-      const store = yield* SessionStore.Service
       const expected = { _tag: "Session.MessageDecodeError", sessionID, messageID }
-      expect(yield* store.messages({ sessionID }).pipe(Effect.flip)).toMatchObject(expected)
       expect(yield* sessions.messages({ sessionID }).pipe(Effect.flip)).toMatchObject(expected)
       expect(yield* sessions.context(sessionID).pipe(Effect.flip)).toMatchObject(expected)
       expect(yield* sessions.message({ sessionID, messageID }).pipe(Effect.catchDefect(Effect.succeed))).toMatchObject(
@@ -291,21 +287,6 @@ describe("SessionProjector", () => {
     }).pipe(Effect.provide(sessionsLayer)),
   )
 
-  it.effect("checks session existence before resolving a missing message cursor", () =>
-    Effect.gen(function* () {
-      const sessions = yield* Session.Service
-      const missing = Session.ID.make("ses_missing")
-      expect(
-        yield* sessions
-          .messages({
-            sessionID: missing,
-            cursor: { id: SessionMessage.ID.make("msg_missing"), direction: "next" },
-          })
-          .pipe(Effect.flip),
-      ).toEqual(new Session.NotFoundError({ sessionID: missing }))
-    }).pipe(Effect.provide(sessionsLayer)),
-  )
-
   it.effect("consumes the pending row and projects the message at promotion", () =>
     Effect.gen(function* () {
       const db = yield* seedSession()

packages/core/test/session-prompt-hooks.test.ts

@@ -38,11 +38,11 @@ const it = testEffect(
       PluginRuntime.providerNodeWithCell(runtime),
     ]),
     [
-      [Bus.node, Bus.configured({ persist: true })],
-      [Global.node, tempGlobalLayer],
-      [Watcher.node, Watcher.configured({ enabled: false })],
-      [SessionExecution.node, SessionExecution.noopLayer],
-      [PluginRuntime.node, PluginRuntime.layerWithCell(runtime)],
+      Bus.node.replace(Bus.configured({ persist: true })),
+      Global.node.replace(tempGlobalLayer),
+      Watcher.node.replace(Watcher.configured({ enabled: false })),
+      SessionExecution.node.replace(SessionExecution.noopLayer),
+      PluginRuntime.node.replace(PluginRuntime.layerWithCell(runtime)),
     ],
   ),
 )

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

@@ -86,9 +86,9 @@ const locations = makeGlobalNode({
             return Layer.merge(SessionRevert.layer, SessionPrompt.layer).pipe(
               Layer.provideMerge(
                 Layer.mergeAll(
-                  LayerNode.compile(LayerNode.group([PluginHooks.node, Skill.node]), [
-                    [Bus.node, Layer.succeed(Bus.Service, bus)],
-                  ]),
+                  LayerNode.compile(LayerNode.group([PluginHooks.node, Skill.node]), {
+                    replacements: [Bus.node.replace(Layer.succeed(Bus.Service, bus))],
+                  }),
                   Layer.mock(Image.Service, {
                     normalize: (_resource, content) =>
                       ready
@@ -122,9 +122,9 @@ const it = testEffect(
   AppNodeBuilder.build(
     LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node, Session.node]),
     [
-      [Bus.node, Bus.configured({ persist: true })],
-      [SessionExecution.node, execution],
-      [LocationServiceMap.node, locations],
+      Bus.node.replace(Bus.configured({ persist: true })),
+      SessionExecution.node.replace(execution),
+      LocationServiceMap.node.replace(locations),
     ],
   ),
 )

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

@@ -39,9 +39,9 @@ const it = testEffect(
       LocationServiceMap.node,
     ]),
     [
-      [Project.node, globalProjectNode],
-      [SessionExecution.node, SessionExecution.noopLayer],
-      [SessionModelTransport.node, transport],
+      Project.node.replace(globalProjectNode),
+      SessionExecution.node.replace(SessionExecution.noopLayer),
+      SessionModelTransport.node.replace(transport),
     ],
   ),
 )

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

@@ -31,9 +31,9 @@ const it = testEffect(
   AppNodeBuilder.build(
     LayerNode.group([Database.node, Bus.node, SessionProjector.node, Session.node, LocationServiceMap.node]),
     [
-      [Bus.node, Bus.configured({ persist: true })],
-      [Global.node, tempGlobalLayer],
-      [SessionExecution.node, SessionExecution.noopLayer],
+      Bus.node.replace(Bus.configured({ persist: true })),
+      Global.node.replace(tempGlobalLayer),
+      SessionExecution.node.replace(SessionExecution.noopLayer),
     ],
   ),
 )

packages/core/test/session-runner-recorded.test.ts

@@ -1,6 +1,6 @@
 import { HttpRecorder } from "@opencode-ai/http-recorder"
 import { OpenAIChat } from "@opencode-ai/ai/protocols/openai-chat"
-import { Auth, LLMClient, RequestExecutor } from "@opencode-ai/ai/route"
+import { Auth, LLMClient, type LLMClientService, RequestExecutor } from "@opencode-ai/ai/route"
 import { Catalog } from "@opencode-ai/core/catalog"
 import { Database } from "@opencode-ai/core/database/database"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
@@ -100,22 +100,22 @@ const promptCatalog = Layer.mock(Catalog.Service, {
     small: () => Effect.undefined,
   },
 })
-const runnerLayer = (llmClient: Layer.Layer<typeof LLMClient.Service>) =>
+const runnerLayer = (llmClient: Layer.Layer<LLMClientService>) =>
   AppNodeBuilder.build(SessionRunnerLLM.node, [
-    [Snapshot.node, Snapshot.noopLayer],
-    [LayerNodePlatform.llmClient, llmClient],
-    [SessionRunnerModel.node, models],
-    [InstructionBuiltIns.node, systemContext],
-    [InstructionDiscovery.node, instructionContext],
-    [Location.node, Location.boundNode({ directory: AbsolutePath.make("/project") })],
-    [SkillInstructions.node, skillInstructions],
-    [ReferenceInstructions.node, referenceInstructions],
-    [McpInstructions.node, mcpInstructions],
-    [Config.node, config],
-    [Permission.node, permission],
-    [PluginSupervisor.node, pluginSupervisor],
+    Snapshot.node.replace(Snapshot.noopLayer),
+    LayerNodePlatform.llmClient.replace(llmClient),
+    SessionRunnerModel.node.replace(models),
+    InstructionBuiltIns.node.replace(systemContext),
+    InstructionDiscovery.node.replace(instructionContext),
+    Location.node.replace(Location.boundNode({ directory: AbsolutePath.make("/project") })),
+    SkillInstructions.node.replace(skillInstructions),
+    ReferenceInstructions.node.replace(referenceInstructions),
+    McpInstructions.node.replace(mcpInstructions),
+    Config.node.replace(config),
+    Permission.node.replace(permission),
+    PluginSupervisor.node.replace(pluginSupervisor),
   ])
-const execution = (llmClient: Layer.Layer<typeof LLMClient.Service>) =>
+const execution = (llmClient: Layer.Layer<LLMClientService>) =>
   Layer.effect(
     SessionExecution.Service,
     Effect.gen(function* () {
@@ -133,7 +133,7 @@ const execution = (llmClient: Layer.Layer<typeof LLMClient.Service>) =>
       })
     }),
   ).pipe(Layer.provide(runnerLayer(llmClient)))
-const testLayer = (llmClient: Layer.Layer<typeof LLMClient.Service>) =>
+const testLayer = (llmClient: Layer.Layer<LLMClientService>) =>
   AppNodeBuilder.build(
     LayerNode.group([
       Database.node,
@@ -155,21 +155,21 @@ const testLayer = (llmClient: Layer.Layer<typeof LLMClient.Service>) =>
       Session.node,
     ]),
     [
-      [Bus.node, Bus.configured({ persist: true })],
-      [LocationServiceMap.node, promptLocationNode],
-      [LayerNodePlatform.llmClient, llmClient],
-      [Permission.node, permission],
-      [Catalog.node, promptCatalog],
-      [SessionRunnerModel.node, models],
-      [InstructionBuiltIns.node, systemContext],
-      [InstructionDiscovery.node, instructionContext],
-      [Location.node, Location.boundNode({ directory: AbsolutePath.make("/project") })],
-      [SkillInstructions.node, skillInstructions],
-      [ReferenceInstructions.node, referenceInstructions],
-      [Config.node, config],
-      [Snapshot.node, Snapshot.noopLayer],
-      [PluginSupervisor.node, pluginSupervisor],
-      [SessionExecution.node, execution(llmClient)],
+      Bus.node.replace(Bus.configured({ persist: true })),
+      LocationServiceMap.node.replace(promptLocationNode),
+      LayerNodePlatform.llmClient.replace(llmClient),
+      Permission.node.replace(permission),
+      Catalog.node.replace(promptCatalog),
+      SessionRunnerModel.node.replace(models),
+      InstructionBuiltIns.node.replace(systemContext),
+      InstructionDiscovery.node.replace(instructionContext),
+      Location.node.replace(Location.boundNode({ directory: AbsolutePath.make("/project") })),
+      SkillInstructions.node.replace(skillInstructions),
+      ReferenceInstructions.node.replace(referenceInstructions),
+      Config.node.replace(config),
+      Snapshot.node.replace(Snapshot.noopLayer),
+      PluginSupervisor.node.replace(pluginSupervisor),
+      SessionExecution.node.replace(execution(llmClient)),
     ],
   )
 const it = testEffect(testLayer(client))

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

@@ -127,7 +127,7 @@ test("provider-executed success derives content and retains provider result stat
 
 testEffect(
   AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, SessionProjector.node]), [
-    [Bus.node, Bus.configured({ persist: true })],
+    Bus.node.replace(Bus.configured({ persist: true })),
   ]),
 ).effect("commits a hosted tool result when cancellation races with the aggregate lock", () =>
   Effect.gen(function* () {

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

@@ -408,22 +408,22 @@ const layer = Layer.unwrap(
       },
     })
     const replacements: LayerNode.Replacements = [
-      [Snapshot.node, Snapshot.noopLayer],
-      [LayerNodePlatform.llmClient, TestLLM.clientLayer],
-      [SessionRunnerModel.node, models],
-      [InstructionBuiltIns.node, systemContext],
-      [InstructionDiscovery.node, instructionContext],
-      [Location.node, Location.boundNode({ directory: AbsolutePath.make("/project") })],
-      [SkillInstructions.node, skillInstructions],
-      [ReferenceInstructions.node, referenceInstructions],
-      [Permission.node, permission],
-      [Config.node, config],
-      [PluginSupervisor.node, pluginSupervisor],
-      [SessionModelTransport.node, modelTransport],
+      Snapshot.node.replace(Snapshot.noopLayer),
+      LayerNodePlatform.llmClient.replace(TestLLM.clientLayer.pipe(Layer.provide(testLLM))),
+      SessionRunnerModel.node.replace(models),
+      InstructionBuiltIns.node.replace(systemContext),
+      InstructionDiscovery.node.replace(instructionContext),
+      Location.node.replace(Location.boundNode({ directory: AbsolutePath.make("/project") })),
+      SkillInstructions.node.replace(skillInstructions),
+      ReferenceInstructions.node.replace(referenceInstructions),
+      Permission.node.replace(permission),
+      Config.node.replace(config),
+      PluginSupervisor.node.replace(pluginSupervisor),
+      SessionModelTransport.node.replace(modelTransport),
     ]
     const runnerLayer = AppNodeBuilder.build(SessionRunnerLLM.node, [
       ...replacements,
-      [McpInstructions.node, mcpInstructions],
+      McpInstructions.node.replace(mcpInstructions),
     ])
     const execution = Layer.effect(
       SessionExecution.Service,
@@ -485,10 +485,10 @@ const layer = Layer.unwrap(
       ]),
       [
         ...replacements,
-        [Bus.node, Bus.configured({ persist: true })],
-        [LocationServiceMap.node, promptLocationNode],
-        [Catalog.node, promptCatalog],
-        [SessionExecution.node, execution],
+        Bus.node.replace(Bus.configured({ persist: true })),
+        LocationServiceMap.node.replace(promptLocationNode),
+        Catalog.node.replace(promptCatalog),
+        SessionExecution.node.replace(execution),
       ],
     )
   }),

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

@@ -54,8 +54,8 @@ const executionLayer = Layer.effect(
 
 const it = testEffect(
   AppNodeBuilder.build(LayerNode.group([Bus.node, Session.node, SessionExecution.node, LocationServiceMap.node]), [
-    [Bus.node, Bus.configured({ persist: true })],
-    [SessionExecution.node, executionLayer],
+    Bus.node.replace(Bus.configured({ persist: true })),
+    SessionExecution.node.replace(executionLayer.pipe(Layer.provide(controlLayer))),
   ]).pipe(Layer.provideMerge(controlLayer)),
 )
 

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

@@ -67,9 +67,9 @@ const it = testEffect(
   AppNodeBuilder.build(
     LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node, Session.node]),
     [
-      [LocationServiceMap.node, locations],
-      [Project.node, globalProjectNode],
-      [SessionExecution.node, SessionExecution.noopLayer],
+      LocationServiceMap.node.replace(locations),
+      Project.node.replace(globalProjectNode),
+      SessionExecution.node.replace(SessionExecution.noopLayer),
     ],
   ),
 )

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

@@ -27,7 +27,7 @@ import { testEffect } from "./lib/effect"
 const it = testEffect(
   Layer.merge(
     AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, SessionProjector.node, ToolOutput.node]), [
-      [Bus.node, Bus.configured({ persist: true })],
+      Bus.node.replace(Bus.configured({ persist: true })),
     ]),
     TestLLM.testLayer(),
   ),

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

@@ -1,190 +0,0 @@
-import { describe, expect } from "bun:test"
-import { Effect } from "effect"
-import { Bus } from "@opencode-ai/core/bus"
-import { Database } from "@opencode-ai/core/database/database"
-import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
-import { ProjectTable } from "@opencode-ai/core/project/sql"
-import { SessionProjector } from "@opencode-ai/core/session/projector"
-import { SessionStore } from "@opencode-ai/core/session/store"
-import { Event } from "@opencode-ai/schema/event"
-import { Project } from "@opencode-ai/schema/project"
-import { AbsolutePath } from "@opencode-ai/schema/schema"
-import { Session } from "@opencode-ai/schema/session"
-import { SessionEvent } from "@opencode-ai/schema/session-event"
-import { SessionMessage } from "@opencode-ai/schema/session-message"
-import { LayerNode } from "@opencode-ai/util/effect/layer-node"
-import { testEffect } from "./lib/effect"
-
-const it = testEffect(
-  AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node]), [
-    [Bus.node, Bus.configured({ persist: true })],
-  ]),
-)
-
-const seedSessions = (rows: { id: string; updated: number }[]) =>
-  Effect.gen(function* () {
-    const database = yield* Database.Service
-    const bus = yield* Bus.Service
-    const directory = AbsolutePath.make("/project")
-    yield* database.db.insert(ProjectTable).values({ id: Project.ID.global, worktree: directory, sandboxes: [] }).run()
-    yield* Effect.forEach(rows, (row) =>
-      Effect.gen(function* () {
-        const sessionID = Session.ID.make(row.id)
-        yield* bus.publish(SessionEvent.Created, {
-          sessionID,
-          projectID: Project.ID.global,
-          location: { directory },
-          slug: "store-test",
-          version: "test",
-        })
-        yield* bus.replay({
-          id: Event.ID.create(),
-          created: row.updated,
-          aggregateID: sessionID,
-          seq: 1,
-          type: Bus.versionedType(SessionEvent.Renamed.type, 1),
-          data: { sessionID, title: row.id },
-        })
-      }),
-    )
-    return bus
-  })
-
-describe("SessionStore", () => {
-  it.effect("lists by updated time and ID with exclusive two-item pages in either direction", () =>
-    Effect.gen(function* () {
-      yield* seedSessions([
-        { id: "ses_d", updated: 20 },
-        { id: "ses_z", updated: 10 },
-        { id: "ses_a", updated: 30 },
-        { id: "ses_c", updated: 20 },
-        { id: "ses_y", updated: 10 },
-        { id: "ses_e", updated: 30 },
-        { id: "ses_b", updated: 20 },
-      ])
-      const store = yield* SessionStore.Service
-      expect((yield* store.list()).map((session) => String(session.id))).toEqual([
-        "ses_e",
-        "ses_a",
-        "ses_d",
-        "ses_c",
-        "ses_b",
-        "ses_z",
-        "ses_y",
-      ])
-      expect((yield* store.list({ order: "asc" })).map((session) => String(session.id))).toEqual([
-        "ses_y",
-        "ses_z",
-        "ses_b",
-        "ses_c",
-        "ses_d",
-        "ses_a",
-        "ses_e",
-      ])
-      const pages: { order: "asc" | "desc"; direction: "next" | "previous"; ids: string[] }[] = [
-        { order: "asc", direction: "next", ids: ["ses_d", "ses_a"] },
-        { order: "asc", direction: "previous", ids: ["ses_z", "ses_b"] },
-        { order: "desc", direction: "next", ids: ["ses_b", "ses_z"] },
-        { order: "desc", direction: "previous", ids: ["ses_a", "ses_d"] },
-      ]
-      yield* Effect.forEach(pages, (page) =>
-        Effect.gen(function* () {
-          const sessions = yield* store.list({
-            order: page.order,
-            limit: 2,
-            anchor: { id: Session.ID.make("ses_c"), time: 20, direction: page.direction },
-          })
-          expect(sessions.map((session) => String(session.id))).toEqual(page.ids)
-        }),
-      )
-    }),
-  )
-
-  it.effect("pages messages by durable sequence, not timestamp or ID, and scopes cursor lookup", () =>
-    Effect.gen(function* () {
-      const sessionID = Session.ID.make("ses_messages")
-      const foreignID = Session.ID.make("ses_foreign")
-      const bus = yield* seedSessions([
-        { id: sessionID, updated: 0 },
-        { id: foreignID, updated: 0 },
-      ])
-      const store = yield* SessionStore.Service
-      yield* Effect.forEach(
-        [
-          { id: "evt_z", created: 300 },
-          { id: "evt_b", created: 700 },
-          { id: "evt_x", created: 100 },
-          { id: "evt_c", created: 400 },
-          { id: "evt_w", created: 200 },
-          { id: "evt_a", created: 600 },
-          { id: "evt_y", created: 500 },
-        ],
-        (event, index) =>
-          bus.replay({
-            id: Event.ID.make(event.id),
-            created: event.created,
-            aggregateID: sessionID,
-            seq: index + 2,
-            type: Bus.versionedType(SessionEvent.Synthetic.type, 1),
-            data: { sessionID, text: event.id },
-          }),
-      )
-      yield* bus.publish(
-        SessionEvent.Synthetic,
-        { sessionID: foreignID, text: "foreign" },
-        {
-          id: Event.ID.make("evt_foreign"),
-        },
-      )
-      expect((yield* store.messages({ sessionID })).map((message) => String(message.id))).toEqual([
-        "msg_y",
-        "msg_a",
-        "msg_w",
-        "msg_c",
-        "msg_x",
-        "msg_b",
-        "msg_z",
-      ])
-      expect((yield* store.messages({ sessionID, order: "asc" })).map((message) => String(message.id))).toEqual([
-        "msg_z",
-        "msg_b",
-        "msg_x",
-        "msg_c",
-        "msg_w",
-        "msg_a",
-        "msg_y",
-      ])
-      const pages: { order: "asc" | "desc"; direction: "next" | "previous"; ids: string[] }[] = [
-        { order: "asc", direction: "next", ids: ["msg_w", "msg_a"] },
-        { order: "asc", direction: "previous", ids: ["msg_b", "msg_x"] },
-        { order: "desc", direction: "next", ids: ["msg_x", "msg_b"] },
-        { order: "desc", direction: "previous", ids: ["msg_a", "msg_w"] },
-      ]
-      yield* Effect.forEach(pages, (page) =>
-        Effect.gen(function* () {
-          const messages = yield* store.messages({
-            sessionID,
-            order: page.order,
-            limit: 2,
-            cursor: { id: SessionMessage.ID.make("msg_c"), direction: page.direction },
-          })
-          expect(messages.map((message) => String(message.id))).toEqual(page.ids)
-        }),
-      )
-      expect(yield* store.messages({ sessionID: Session.ID.make("ses_missing") })).toEqual([])
-      expect(
-        yield* store.messages({
-          sessionID,
-          cursor: { id: SessionMessage.ID.make("msg_missing"), direction: "next" },
-        }),
-      ).toEqual([])
-      expect(
-        yield* store.messages({
-          sessionID,
-          order: "asc",
-          cursor: { id: SessionMessage.ID.make("msg_foreign"), direction: "next" },
-        }),
-      ).toEqual([])
-    }),
-  )
-})

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

@@ -126,11 +126,11 @@ const it = testEffect(
       SessionTitle.node,
     ]),
     [
-      [llmClient, client],
-      [Catalog.node, catalog],
-      [SessionRunnerModel.node, models],
-      [Location.node, Location.boundNode({ directory: AbsolutePath.make("/project") })],
-      [PluginSupervisor.node, Layer.mock(PluginSupervisor.Service, { flush: Effect.void })],
+      llmClient.replace(client),
+      Catalog.node.replace(catalog),
+      SessionRunnerModel.node.replace(models),
+      Location.node.replace(Location.boundNode({ directory: AbsolutePath.make("/project") })),
+      PluginSupervisor.node.replace(Layer.mock(PluginSupervisor.Service, { flush: Effect.void })),
     ],
   ),
 )

packages/core/test/session-tool-progress.test.ts

@@ -21,7 +21,7 @@ import { testEffect } from "./lib/effect"
 
 const it = testEffect(
   AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, SessionProjector.node]), [
-    [Bus.node, Bus.configured({ persist: true })],
+    Bus.node.replace(Bus.configured({ persist: true })),
   ]),
 )
 const model = { id: Model.ID.make("model"), providerID: Provider.ID.make("provider") }

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

@@ -25,9 +25,9 @@ const it = testEffect(
   AppNodeBuilder.build(
     LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node, Session.node]),
     [
-      [Bus.node, Bus.configured({ persist: true })],
-      [Project.node, globalProjectNode],
-      [SessionExecution.node, SessionExecution.noopLayer],
+      Bus.node.replace(Bus.configured({ persist: true })),
+      Project.node.replace(globalProjectNode),
+      SessionExecution.node.replace(SessionExecution.noopLayer),
     ],
   ),
 )
@@ -186,8 +186,8 @@ describe("Session.view", () => {
       const targetLayer = AppNodeBuilder.build(
         LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node]),
         [
-          [Database.node, Database.configured({ path: path.join(tmp.path, "target.sqlite") })],
-          [Bus.node, Bus.configured({ persist: true })],
+          Database.node.replace(Database.configured({ path: path.join(tmp.path, "target.sqlite") })),
+          Bus.node.replace(Bus.configured({ persist: true })),
         ],
       )
 

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

@@ -22,10 +22,7 @@ const execution = Layer.mock(SessionExecution.Service, {
 const it = testEffect(
   AppNodeBuilder.build(
     LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node, Session.node]),
-    [
-      [Project.node, globalProjectNode],
-      [SessionExecution.node, execution],
-    ],
+    [Project.node.replace(globalProjectNode), SessionExecution.node.replace(execution)],
   ),
 )
 

packages/core/test/shared-schema.test.ts

@@ -2,7 +2,6 @@ import { expect, test } from "bun:test"
 import { Schema } from "effect"
 import { Agent } from "@opencode-ai/core/agent"
 import { Session } from "@opencode-ai/core/session"
-import { SessionStore } from "@opencode-ai/core/session/store"
 import { Location } from "@opencode-ai/schema/location"
 import { Model } from "@opencode-ai/schema/model"
 import { Provider } from "@opencode-ai/schema/provider"
@@ -127,7 +126,6 @@ test("Core reuses the canonical shared schemas", async () => {
     [Session.ID, schemaSession.Session.ID],
     [Session.Info, schemaSession.Session.Info],
     [Session.ListAnchor, schemaSession.Session.ListAnchor],
-    [Session.ListInput, SessionStore.ListInput],
     [coreSessionInbox.Delivery, SessionInbox.Delivery],
     [coreSessionInbox.Item, SessionInbox.Item],
     [coreSessionInbox.User, SessionInbox.User],

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

@@ -14,7 +14,7 @@ const withStore = <A, E, R>(body: (fs: FSUtil.Interface, root: string) => Effect
     Effect.promise(() => tmpdir()),
     (tmp) => {
       const layer = AppNodeBuilder.build(LayerNode.group([FSUtil.node, Global.node]), [
-        [Global.node, Global.layerWith({ data: tmp.path })],
+        Global.node.replace(Global.layerWith({ data: tmp.path })),
       ])
       return Effect.gen(function* () {
         const fs = yield* FSUtil.Service

packages/core/test/skill-discovery.test.ts

@@ -44,7 +44,7 @@ const fixture = Effect.gen(function* () {
           return yield* discovery.pull(base)
         }).pipe(
           Effect.provide(
-            AppNodeBuilder.build(SkillDiscovery.node, [[Global.node, Global.layerWith({ cache: tmp.path })]]),
+            AppNodeBuilder.build(SkillDiscovery.node, [Global.node.replace(Global.layerWith({ cache: tmp.path }))]),
           ),
         )
         return { directories, requests: state.requests.slice() }

packages/core/test/skill/instructions.test.ts

@@ -41,7 +41,7 @@ const manual = Skill.Info.make({
 
 const layer = (list: () => Skill.Info[]) =>
   AppNodeBuilder.build(SkillInstructions.node, [
-    [Skill.node, Layer.mock(Skill.Service, { list: () => Effect.succeed(list()) })],
+    Skill.node.replace(Layer.mock(Skill.Service, { list: () => Effect.succeed(list()) })),
   ])
 
 describe("SkillInstructions", () => {