refactor(core): narrow shell spawn handling

Co-authored-by: Aiden Cline <63023139+rekram1-node@users.noreply.github.com>

packages/ai/src/protocols/openai-chat.ts

@@ -371,12 +371,13 @@ const lowerAssistantMessage = Effect.fn("OpenAIChat.lowerAssistantMessage")(func
     return text
   })()
   const cached = message.content.findLast((part) => "cache" in part && part.cache !== undefined)
+  const cacheControl = options.cacheControl?.(cached && "cache" in cached ? cached.cache : undefined)
   const result = {
     role: "assistant" as const,
-    content: content.length === 0 ? null : ProviderShared.joinText(content),
-    tool_calls: toolCalls.length === 0 ? undefined : toolCalls,
-    reasoning_details: details,
-    cache_control: options.cacheControl?.(cached && "cache" in cached ? cached.cache : undefined),
+    content: content.length > 0 ? content.map((part) => part.text).join("") : toolCalls.length > 0 ? null : "",
+    ...(toolCalls.length > 0 ? { tool_calls: toolCalls } : {}),
+    ...(details !== undefined ? { reasoning_details: details } : {}),
+    ...(cacheControl !== undefined ? { cache_control: cacheControl } : {}),
   }
   if (field === undefined || reasoningText === undefined) return result
   return { ...result, [field]: reasoningText }
@@ -716,14 +717,13 @@ const step = (state: ParserState, event: OpenAIChatEvent) =>
       return [{ ...state, usage }, events] as const
     }
 
-    const reasoningField = state.reasoningField ?? (!state.lifecycle.text.has("text-0") ? reasoning?.field : undefined)
+    const reasoningField = state.reasoningField ?? reasoning?.field
     const detailDelta = Array.isArray(delta?.reasoning_details) ? delta.reasoning_details : undefined
     if (detailDelta !== undefined) appendReasoningDetails(state.reasoningDetails, detailDelta)
     const reasoningDetailsObserved = state.reasoningDetailsObserved || detailDelta !== undefined
     const deltaMetadata = reasoningMetadata(reasoningField)
     const text = detailDelta?.length ? (detailText(detailDelta) ?? reasoning?.text) : reasoning?.text
-    if (!state.lifecycle.text.has("text-0") && text !== undefined)
-      lifecycle = Lifecycle.reasoningDelta(lifecycle, events, "reasoning-0", text, deltaMetadata)
+    if (text !== undefined) lifecycle = Lifecycle.reasoningDelta(lifecycle, events, "reasoning-0", text, deltaMetadata)
     else if (
       reasoningDetailsObserved &&
       !lifecycle.reasoning.has("reasoning-0") &&
@@ -812,14 +812,18 @@ const step = (state: ParserState, event: OpenAIChatEvent) =>
 
 const finishEvents = (state: ParserState): ReadonlyArray<LLMEvent> => {
   const events: LLMEvent[] = []
-  const hasToolCalls = state.toolCallEvents.length > 0
+  const toolCallEvents =
+    state.finishReason === undefined && Object.keys(state.tools).length > 0
+      ? Effect.runSync(ToolStream.finishAll(ADAPTER, state.tools)).events
+      : state.toolCallEvents
+  const hasToolCalls = toolCallEvents.length > 0
   const reason = state.finishReason
     ? {
         ...state.finishReason,
         normalized:
           state.finishReason.normalized === "stop" && hasToolCalls ? "tool-calls" : state.finishReason.normalized,
       }
-    : undefined
+    : { normalized: hasToolCalls ? ("tool-calls" as const) : ("unknown" as const) }
   const metadata = reasoningMetadata(
     state.reasoningField,
     state.reasoningDetailsObserved ? state.reasoningDetails : undefined,
@@ -829,9 +833,9 @@ const finishEvents = (state: ParserState): ReadonlyArray<LLMEvent> => {
       ? Lifecycle.reasoningStart(state.lifecycle, events, "reasoning-0", reasoningMetadata(state.reasoningField))
       : state.lifecycle
   const ended = Lifecycle.reasoningEnd(started, events, "reasoning-0", metadata)
-  const lifecycle = state.toolCallEvents.length ? Lifecycle.stepStart(ended, events) : ended
-  events.push(...state.toolCallEvents)
-  if (reason) Lifecycle.finish(lifecycle, events, { reason, usage: state.usage })
+  const lifecycle = toolCallEvents.length ? Lifecycle.stepStart(ended, events) : ended
+  events.push(...toolCallEvents)
+  Lifecycle.finish(lifecycle, events, { reason, usage: state.usage })
   return events
 }
 

packages/ai/test/provider/openai-chat.test.ts

@@ -102,6 +102,24 @@ describe("OpenAI Chat route", () => {
     }),
   )
 
+  it.effect("concatenates assistant text parts without adding separators", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model,
+          messages: [
+            Message.assistant([
+              { type: "text", text: "Hello" },
+              { type: "text", text: " world" },
+            ]),
+          ],
+        }),
+      )
+
+      expect(prepared.body.messages).toEqual([{ role: "assistant", content: "Hello world" }])
+    }),
+  )
+
   it.effect("writes reasoning to a configured custom field on every assistant message", () =>
     Effect.gen(function* () {
       const prepared = yield* compileRequest(
@@ -578,7 +596,7 @@ describe("OpenAI Chat route", () => {
         }),
       )
 
-      expect(prepared.body.messages).toEqual([{ role: "assistant", content: null, reasoning_content: "hidden" }])
+      expect(prepared.body.messages).toEqual([{ role: "assistant", content: "", reasoning_content: "hidden" }])
     }),
   )
 
@@ -827,7 +845,7 @@ describe("OpenAI Chat route", () => {
     }),
   )
 
-  it.effect("ignores scalar reasoning after content starts", () =>
+  it.effect("preserves scalar reasoning after content starts", () =>
     Effect.gen(function* () {
       const details = [{ type: "reasoning.text", text: "detail", format: "unknown", index: 0 }]
       const response = yield* LLMClient.generate(request).pipe(
@@ -843,11 +861,11 @@ describe("OpenAI Chat route", () => {
         ),
       )
 
-      expect(response.reasoning).toBe("detail")
-      expect(response.events.filter(LLMEvent.is.reasoningStart)).toHaveLength(1)
-      expect(response.events.filter(LLMEvent.is.reasoningEnd)).toHaveLength(1)
+      expect(response.reasoning).toBe("detailscalar")
+      expect(response.events.filter(LLMEvent.is.reasoningStart)).toHaveLength(2)
+      expect(response.events.filter(LLMEvent.is.reasoningEnd)).toHaveLength(2)
       expect(response.message.content.find((part) => part.type === "reasoning")?.providerMetadata).toEqual({
-        openai: { reasoningDetails: details },
+        openai: { reasoningField: "reasoning", reasoningDetails: details },
       })
     }),
   )
@@ -947,7 +965,7 @@ describe("OpenAI Chat route", () => {
       expect(response.events.filter(LLMEvent.is.reasoningEnd)).toHaveLength(1)
 
       const replay = yield* compileRequest(LLM.request({ model, messages: [response.message] }))
-      expect(replay.body.messages).toEqual([{ role: "assistant", content: null, reasoning_details: details }])
+      expect(replay.body.messages).toEqual([{ role: "assistant", content: "", reasoning_details: details }])
     }),
   )
 
@@ -997,7 +1015,7 @@ describe("OpenAI Chat route", () => {
       )
 
       expect(replay.body.messages).toEqual([
-        { role: "assistant", content: null, reasoning: "firstsecond", reasoning_details: [first, second] },
+        { role: "assistant", content: "", reasoning: "firstsecond", reasoning_details: [first, second] },
       ])
     }),
   )
@@ -1022,7 +1040,7 @@ describe("OpenAI Chat route", () => {
       )
 
       expect(replay.body.messages).toEqual([
-        { role: "assistant", content: null, reasoning_content: "AB", reasoning_details: [detail] },
+        { role: "assistant", content: "", reasoning_content: "AB", reasoning_details: [detail] },
       ])
     }),
   )
@@ -1044,7 +1062,7 @@ describe("OpenAI Chat route", () => {
       )
 
       expect(replay.body.messages).toEqual([
-        { role: "assistant", content: null, reasoning_content: "thinking", reasoning_details: details },
+        { role: "assistant", content: "", reasoning_content: "thinking", reasoning_details: details },
       ])
     }),
   )
@@ -1152,7 +1170,7 @@ describe("OpenAI Chat route", () => {
     }),
   )
 
-  it.effect("fails a streamed tool call when the provider ends without a finish reason", () =>
+  it.effect("finalizes a streamed tool call when the provider ends without a finish reason", () =>
     Effect.gen(function* () {
       const body = sseEvents(
         deltaChunk({
@@ -1164,27 +1182,31 @@ describe("OpenAI Chat route", () => {
       const input = LLMRequest.update(request, {
         tools: [ToolDefinition.make({ name: "lookup", description: "Lookup data", inputSchema: { type: "object" } })],
       })
-      const events: LLMEvent[] = []
-      const streamError = yield* LLMClient.stream(input).pipe(
-        Stream.runForEach((event) => Effect.sync(() => events.push(event))),
-        Effect.flip,
-        Effect.provide(fixedResponse(body)),
-      )
-      const error = yield* LLMClient.generate(input).pipe(Effect.provide(fixedResponse(body)), Effect.flip)
+      const response = yield* LLMClient.generate(input).pipe(Effect.provide(fixedResponse(body)))
 
-      expect(events).toEqual([
+      expect(response.events).toEqual([
         { type: "step-start", index: 0 },
         { type: "tool-input-start", id: "call_1", name: "lookup", providerMetadata: undefined },
         { type: "tool-input-delta", id: "call_1", name: "lookup", text: '{"query"' },
         { type: "tool-input-delta", id: "call_1", name: "lookup", text: ':"weather"}' },
+        { type: "tool-input-end", id: "call_1", name: "lookup", providerMetadata: undefined },
+        {
+          type: "tool-call",
+          id: "call_1",
+          name: "lookup",
+          input: { query: "weather" },
+          providerExecuted: undefined,
+          providerMetadata: undefined,
+        },
+        {
+          type: "step-finish",
+          index: 0,
+          reason: { normalized: "tool-calls" },
+          usage: undefined,
+          providerMetadata: undefined,
+        },
+        { type: "finish", reason: { normalized: "tool-calls" }, usage: undefined },
       ])
-      expect(events.filter(LLMEvent.is.toolCall)).toEqual([])
-      expect(streamError.reason).toMatchObject({
-        _tag: "InvalidProviderOutput",
-        classification: "incomplete-stream",
-      })
-      expect(streamError.message).toContain("The provider response ended unexpectedly.")
-      expect(error.message).toContain("The provider response ended unexpectedly.")
     }),
   )
 

packages/core/src/session.ts

@@ -645,7 +645,9 @@ const layer = Layer.effect(
             yield* execution.awaitIdle(input.sessionID)
             const started = yield* Effect.gen(function* () {
               const shell = yield* Shell.Service
-              return yield* shell.create({ command: input.command, cwd: session.location.directory, timeout: 0 })
+              return yield* shell
+                .create({ command: input.command, cwd: session.location.directory, timeout: 0 })
+                .pipe(Effect.orDie)
             }).pipe(Effect.provide(locations.get(session.location)))
             yield* bus.publish(
               SessionEvent.Shell.Started,

packages/core/src/shell.ts

@@ -5,6 +5,7 @@ import { Context, Deferred, Duration, Effect, Fiber, Layer, Schema, Stream } fro
 import { ChildProcess } from "effect/unstable/process"
 import { produce } from "immer"
 import { Shell } from "@opencode-ai/schema/shell"
+import { AppProcess } from "@opencode-ai/util/process"
 import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
 import { Config } from "./config"
 import { Bus } from "./bus"
@@ -50,7 +51,7 @@ export interface Interface {
   readonly create: <E = never, R = never>(
     input: Shell.CreateInput,
     before?: (input: ShellCreateBefore) => Effect.Effect<void, E, R>,
-  ) => Effect.Effect<Shell.Info, E, R>
+  ) => Effect.Effect<Shell.Info, E | AppProcess.AppProcessError, R>
   // Currently running commands only; exited shells are retained for get/output but excluded here.
   readonly list: () => Effect.Effect<Shell.Info[]>
   readonly get: (id: Shell.ID) => Effect.Effect<Shell.Info, NotFoundError>
@@ -213,19 +214,23 @@ export const layer = (options?: ShellSelect.Options) =>
         // Spawn through the Environment and stream combined output to the file. The handle is scope-bound, so
         // the managing fiber keeps its scope open until the command terminates (it awaits `done` at the
         // end). `create` returns once `ready` resolves with the registered session.
-        const ready = Deferred.makeUnsafe<Active>()
+        const ready = Deferred.makeUnsafe<Active, AppProcess.AppProcessError>()
         runFork(
           Effect.scoped(
             Effect.gen(function* () {
-              const handle = yield* environment.spawner.spawn(
-                ChildProcess.make(invocation.shell, args, {
-                  cwd: invocation.cwd,
-                  env: invocation.env,
-                  stdin: "ignore",
-                  detached: process.platform !== "win32",
-                  forceKillAfter: Duration.seconds(3),
-                }),
-              )
+              const handle = yield* environment.spawner
+                .spawn(
+                  ChildProcess.make(invocation.shell, args, {
+                    cwd: invocation.cwd,
+                    env: invocation.env,
+                    stdin: "ignore",
+                    detached: process.platform !== "win32",
+                    forceKillAfter: Duration.seconds(3),
+                  }),
+                )
+                .pipe(
+                  Effect.mapError((cause) => new AppProcess.AppProcessError({ command: invocation.command, cause })),
+                )
               const session: Active = {
                 info: produce(info, (draft) => {
                   draft.pid = handle.pid
@@ -327,7 +332,7 @@ export const layer = (options?: ShellSelect.Options) =>
               // release (kill) the process before its exit is observed.
               yield* Deferred.await(session.done).pipe(Effect.catch(() => Effect.void))
             }),
-          ).pipe(Effect.catch(() => Effect.void)),
+          ).pipe(Effect.catchTag("AppProcessError", (error) => Deferred.fail(ready, error))),
         )
 
         const session = yield* Deferred.await(ready)

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

@@ -286,6 +286,31 @@ describe("ShellTool", () => {
     ),
   )
 
+  it.live(
+    "reports a command that fails to spawn",
+    () =>
+      Effect.acquireUseRelease(
+        Effect.promise(() => tmpdir()),
+        (tmp) => {
+          reset()
+          const command = "printf before\0after"
+          return withSession(tmp.path, (registry) =>
+            executeTool(registry, call({ command })).pipe(
+              Effect.andThen((settled) =>
+                Effect.sync(() => {
+                  expect(settled.status).toBe("error")
+                  if (settled.status !== "error") return
+                  expect(settled.error?.message).toContain("Command failed")
+                }),
+              ),
+            ),
+          )
+        },
+        (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]().then(() => undefined)),
+      ),
+    { timeout: 2_000 },
+  )
+
   it.live("permissions compound commands separately", () =>
     Effect.acquireUseRelease(
       Effect.promise(() => tmpdir()),

packages/server/src/handlers/shell.ts

@@ -21,7 +21,9 @@ export const ShellHandler = HttpApiBuilder.group(Api, "server.shell", (handlers)
         Effect.fn(function* (ctx) {
           const shell = yield* Shell.Service
           const location = yield* Location.Service
-          return yield* response(shell.create({ ...ctx.payload, cwd: ctx.payload.cwd || location.directory }))
+          return yield* response(
+            shell.create({ ...ctx.payload, cwd: ctx.payload.cwd || location.directory }).pipe(Effect.orDie),
+          )
         }),
       )
       .handle(

packages/util/src/cross-spawn-spawner.ts

@@ -258,7 +258,13 @@ const makeCrossSpawnSpawner = Effect.gen(function* () {
   const spawn = (command: ChildProcess.StandardCommand, opts: NodeChildProcess.SpawnOptions) =>
     Effect.callback<readonly [NodeChildProcess.ChildProcess, ExitSignal], PlatformError.PlatformError>((resume) => {
       const signal = Deferred.makeUnsafe<readonly [code: number | null, signal: NodeJS.Signals | null]>()
-      const proc = launch(command.command, command.args, opts)
+      let proc: NodeChildProcess.ChildProcess
+      try {
+        proc = launch(command.command, command.args, opts)
+      } catch (err) {
+        resume(Effect.fail(toPlatformError("spawn", toError(err), command)))
+        return Effect.void
+      }
       let end = false
       let exit: readonly [code: number | null, signal: NodeJS.Signals | null] | undefined
       proc.on("error", (err) => {