fix(ai): derive Anthropic tool finish reason

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

packages/ai/src/protocols/anthropic-messages.ts

@@ -303,6 +303,7 @@ type AnthropicEvent = Schema.Schema.Type<typeof AnthropicEvent>
 
 interface ParserState {
   readonly tools: ToolStream.State<number>
+  readonly hasLocalToolCalls: boolean
   readonly reasoningSignatures: Readonly<Record<number, string>>
   readonly usage?: Usage
   readonly pendingFinish?: {
@@ -668,7 +669,12 @@ const fromRequest = Effect.fn("AnthropicMessages.fromRequest")(function* (reques
 // =============================================================================
 // Stream Parsing
 // =============================================================================
-const mapFinishReason = (reason: string | null | undefined): FinishReason => {
+const mapFinishReason = (reason: string | null | undefined, hasLocalToolCalls: boolean): FinishReason => {
+  if (
+    hasLocalToolCalls &&
+    (reason === undefined || reason === null || reason === "end_turn" || reason === "stop_sequence")
+  )
+    return "tool-calls"
   if (reason === "end_turn" || reason === "stop_sequence" || reason === "pause_turn") return "stop"
   if (reason === "max_tokens" || reason === "model_context_window_exceeded") return "length"
   if (reason === "tool_use") return "tool-calls"
@@ -931,7 +937,17 @@ const onContentBlockStop = Effect.fn("AnthropicMessages.onContentBlockStop")(fun
   events.push(...resultEvents)
   const reasoningSignatures = { ...state.reasoningSignatures }
   delete reasoningSignatures[event.index]
-  return [{ ...state, lifecycle, tools: result.tools, reasoningSignatures }, events] satisfies StepResult
+  return [
+    {
+      ...state,
+      hasLocalToolCalls:
+        state.hasLocalToolCalls || resultEvents.some((item) => item.type === "tool-call" && !item.providerExecuted),
+      lifecycle,
+      tools: result.tools,
+      reasoningSignatures,
+    },
+    events,
+  ] satisfies StepResult
 })
 
 const onMessageDelta = (state: ParserState, event: AnthropicEvent): StepResult => {
@@ -942,7 +958,7 @@ const onMessageDelta = (state: ParserState, event: AnthropicEvent): StepResult =
       usage,
       pendingFinish: {
         reason: {
-          normalized: mapFinishReason(event.delta?.stop_reason),
+          normalized: mapFinishReason(event.delta?.stop_reason, state.hasLocalToolCalls),
           raw: event.delta?.stop_reason ?? undefined,
         },
         providerMetadata:
@@ -1013,6 +1029,7 @@ export const protocol = Protocol.make({
     event: Protocol.jsonEvent(AnthropicEvent),
     initial: () => ({
       tools: ToolStream.empty<number>(),
+      hasLocalToolCalls: false,
       reasoningSignatures: {},
       lifecycle: Lifecycle.initial(),
     }),

packages/ai/src/route/client.ts

@@ -20,6 +20,7 @@ import {
   LanguageModel,
   LanguageModelLimits,
   LLMEvent,
+  InvalidProviderOutputReason,
   ProviderID,
   mergeGenerationOptions,
   mergeHttpOptions,
@@ -231,6 +232,17 @@ const streamError = (route: string, message: string, cause: Cause.Cause<unknown>
   return ProviderShared.eventError(route, message, Cause.pretty(cause))
 }
 
+const incompleteStreamError = (route: string) =>
+  new AIError({
+    module: "LLMClient",
+    method: "stream",
+    reason: new InvalidProviderOutputReason({
+      classification: "incomplete-stream",
+      message: "The provider response ended unexpectedly.",
+      route,
+    }),
+  })
+
 const requireTerminalEvent = (route: string) => (events: Stream.Stream<LLMEvent, AIError>) =>
   Stream.suspend(() => {
     let terminal = false
@@ -247,7 +259,7 @@ const requireTerminalEvent = (route: string) => (events: Stream.Stream<LLMEvent,
         Effect.suspend(() =>
           terminal
             ? Effect.void
-            : Effect.fail(ProviderShared.eventError(route, "Provider stream ended without a terminal finish event")),
+            : Effect.fail(incompleteStreamError(route)),
         ),
       ),
     )
@@ -416,10 +428,7 @@ const generateWith = (stream: Interface["stream"]) =>
     const state = yield* stream(request, options).pipe(Stream.runFold(LLMResponse.empty, LLMResponse.reduce))
     const response = LLMResponse.complete(state)
     if (response) return response
-    return yield* ProviderShared.eventError(
-      `${request.model.provider}/${request.model.route.id}`,
-      "Provider stream ended without a terminal finish event",
-    )
+    return yield* incompleteStreamError(`${request.model.provider}/${request.model.route.id}`)
   })
 
 export function stream(request: LLMRequest, options?: StreamOptions): Stream.Stream<LLMEvent, AIError, Service> {

packages/ai/src/schema/errors.ts

@@ -105,6 +105,7 @@ export class InvalidProviderOutputReason extends Schema.Class<InvalidProviderOut
 )({
   _tag: Schema.tag("InvalidProviderOutput"),
   message: Schema.String,
+  classification: Schema.optional(Schema.Literals(["incomplete-stream"])),
   route: Schema.optional(Schema.String),
   raw: Schema.optional(Schema.String),
   providerMetadata: Schema.optional(ProviderMetadata),

packages/ai/test/adapter.test.ts

@@ -133,8 +133,8 @@ describe("llm route", () => {
     Effect.gen(function* () {
       const error = yield* (yield* LLMClient.Service).stream(request).pipe(Stream.runDrain, Effect.flip)
 
-      expect(error.reason).toMatchObject({ _tag: "InvalidProviderOutput" })
-      expect(error.message).toContain("Provider stream ended without a terminal finish event")
+      expect(error.reason).toMatchObject({ _tag: "InvalidProviderOutput", classification: "incomplete-stream" })
+      expect(error.message).toContain("The provider response ended unexpectedly.")
     }),
   )
 

packages/ai/test/provider/anthropic-messages.test.ts

@@ -538,7 +538,8 @@ describe("Anthropic Messages route", () => {
 
       expect(error.reason).toMatchObject({
         _tag: "InvalidProviderOutput",
-        message: "Provider stream ended without a terminal finish event",
+        classification: "incomplete-stream",
+        message: "The provider response ended unexpectedly.",
       })
     }),
   )
@@ -914,6 +915,30 @@ describe("Anthropic Messages route", () => {
     }),
   )
 
+  it.effect("maps a local tool call with end_turn as tool-calls", () =>
+    Effect.gen(function* () {
+      const body = sseEvents(
+        { type: "message_start", message: { usage: { input_tokens: 5 } } },
+        { type: "content_block_start", index: 0, content_block: { type: "tool_use", id: "call_1", name: "lookup" } },
+        {
+          type: "content_block_delta",
+          index: 0,
+          delta: { type: "input_json_delta", partial_json: '{"query":"weather"}' },
+        },
+        { type: "content_block_stop", index: 0 },
+        { type: "message_delta", delta: { stop_reason: "end_turn" }, usage: { output_tokens: 1 } },
+        { type: "message_stop" },
+      )
+      const response = yield* LLMClient.generate(
+        LLMRequest.update(request, {
+          tools: [ToolDefinition.make({ name: "lookup", description: "Lookup data", inputSchema: { type: "object" } })],
+        }),
+      ).pipe(Effect.provide(fixedResponse(body)))
+
+      expect(response.finishReason).toEqual({ normalized: "tool-calls", raw: "end_turn" })
+    }),
+  )
+
   it.effect("keeps malformed server tool input terminal", () =>
     Effect.gen(function* () {
       const body = sseEvents(

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

@@ -1136,9 +1136,12 @@ describe("OpenAI Chat route", () => {
         { type: "tool-input-delta", id: "call_1", name: "lookup", text: ':"weather"}' },
       ])
       expect(events.filter(LLMEvent.is.toolCall)).toEqual([])
-      expect(streamError.reason).toMatchObject({ _tag: "InvalidProviderOutput" })
-      expect(streamError.message).toContain("Provider stream ended without a terminal finish event")
-      expect(error.message).toContain("Provider stream ended without a terminal finish event")
+      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/app/src/context/global-sync/utils.test.ts

@@ -53,7 +53,7 @@ describe("normalizePermissionRequest", () => {
         resources: ["README.md"],
         save: ["*.md"],
         metadata: { path: "README.md" },
-        source: { type: "tool", messageID: "message-1", callID: "call-1" },
+        source: { type: "tool", messageID: "message-1", id: "call-1" },
       }),
     ).toEqual({
       id: "permission-1",

packages/app/src/context/global-sync/utils.ts

@@ -48,7 +48,7 @@ export function normalizePermissionRequest(input: PermissionRequest | LegacyPerm
     always: input.save ?? [],
     metadata: input.metadata ?? {},
     tool:
-      input.source?.type === "tool" ? { messageID: input.source.messageID, callID: input.source.callID } : undefined,
+      input.source?.type === "tool" ? { messageID: input.source.messageID, callID: input.source.id } : undefined,
   }
 }
 

packages/app/src/context/server-sdk.test.ts

@@ -21,12 +21,24 @@ describe("adaptServerEvent", () => {
       id: "evt_1",
       created: 1,
       type: "permission.asked",
-      data: { id: "perm_1", sessionID: "ses_1", action: "read", resources: ["src/**"] },
+      data: {
+        id: "perm_1",
+        sessionID: "ses_1",
+        action: "read",
+        resources: ["src/**"],
+        source: { type: "tool", messageID: "msg_1", id: "call_1" },
+      },
     } as OpenCodeEvent
 
     expect(adaptServerEvent(current)).toMatchObject({
       type: "permission.asked",
-      properties: { id: "perm_1", sessionID: "ses_1", permission: "read", patterns: ["src/**"] },
+      properties: {
+        id: "perm_1",
+        sessionID: "ses_1",
+        permission: "read",
+        patterns: ["src/**"],
+        tool: { messageID: "msg_1", callID: "call_1" },
+      },
       current,
     })
   })
@@ -70,6 +82,26 @@ describe("coalesceServerEvents", () => {
     expect(result[0]?.payload.current).toMatchObject({ id: "evt_2", data: { delta: "hello world" } })
   })
 
+  test("coalesces current tool input deltas by tool ID", () => {
+    const current = (eventID: string, id: string, delta: string) =>
+      adaptServerEvent({
+        id: eventID,
+        created: 1,
+        type: "session.tool.input.delta",
+        location: { directory: "/repo" },
+        data: { sessionID: "ses", assistantMessageID: "msg", id, delta },
+      } as OpenCodeEvent)
+    const result = coalesceServerEvents([
+      { directory: "/repo", payload: current("evt_1", "call_1", "{") },
+      { directory: "/repo", payload: current("evt_2", "call_1", "}") },
+      { directory: "/repo", payload: current("evt_3", "call_2", "[]") },
+    ])
+
+    expect(result).toHaveLength(2)
+    expect(result[0]?.payload.current).toMatchObject({ id: "evt_2", data: { id: "call_1", delta: "{}" } })
+    expect(result[1]?.payload.current).toMatchObject({ id: "evt_3", data: { id: "call_2", delta: "[]" } })
+  })
+
   test("preserves event boundaries and distinct fields", () => {
     const status = {
       directory: "/repo",

packages/app/src/context/server-sdk.tsx

@@ -39,7 +39,7 @@ export function adaptServerEvent(event: OpenCodeEvent): ServerEvent {
         metadata: event.data.metadata ?? {},
         tool:
           event.data.source?.type === "tool"
-            ? { messageID: event.data.source.messageID, callID: event.data.source.callID }
+            ? { messageID: event.data.source.messageID, callID: event.data.source.id }
             : undefined,
       },
       current: event,
@@ -142,7 +142,7 @@ function currentDelta(event: OpenCodeEvent | undefined): CurrentDelta | undefine
 
 function currentDeltaKey(event: CurrentDelta) {
   if (event.type === "session.tool.input.delta")
-    return `${event.type}:${event.data.sessionID}:${event.data.assistantMessageID}:${event.data.callID}`
+    return `${event.type}:${event.data.sessionID}:${event.data.assistantMessageID}:${event.data.id}`
   if (event.type === "session.compaction.delta") return `${event.type}:${event.data.sessionID}`
   return `${event.type}:${event.data.sessionID}:${event.data.assistantMessageID}:${event.data.ordinal}`
 }

packages/app/src/context/server-session-v2-reducer.test.ts

@@ -92,19 +92,19 @@ describe("v2 session reducer", () => {
       ...base,
       id: "evt_tool_start",
       type: "session.tool.input.started",
-      data: { sessionID: "ses_1", assistantMessageID: "msg_assistant", callID: "call_1", name: "bash" },
+      data: { sessionID: "ses_1", assistantMessageID: "msg_assistant", id: "call_1", name: "bash" },
     })
     apply({
       ...base,
       id: "evt_tool_delta",
       type: "session.tool.input.delta",
-      data: { sessionID: "ses_1", assistantMessageID: "msg_assistant", callID: "call_1", delta: "{}" },
+      data: { sessionID: "ses_1", assistantMessageID: "msg_assistant", id: "call_1", delta: "{}" },
     })
     apply({
       ...base,
       id: "evt_tool_called",
       type: "session.tool.called",
-      data: { sessionID: "ses_1", assistantMessageID: "msg_assistant", callID: "call_1", input: {}, executed: true },
+      data: { sessionID: "ses_1", assistantMessageID: "msg_assistant", id: "call_1", input: {}, executed: true },
     })
     apply({
       ...base,
@@ -113,7 +113,7 @@ describe("v2 session reducer", () => {
       data: {
         sessionID: "ses_1",
         assistantMessageID: "msg_assistant",
-        callID: "call_1",
+        id: "call_1",
         metadata: {},
         content: [{ type: "text", text: "done" }],
         executed: true,

packages/app/src/context/server-session-v2-reducer.ts

@@ -241,13 +241,13 @@ export function createV2SessionReducer() {
       case "session.tool.input.started":
         return updateAssistant(source, event.data.assistantMessageID, sessionID, (item) => ({
           ...item,
-          content: item.content.some((content) => content.type === "tool" && content.id === event.data.callID)
+          content: item.content.some((content) => content.type === "tool" && content.id === event.data.id)
             ? item.content
             : [
                 ...item.content,
                 {
                   type: "tool",
-                  id: event.data.callID,
+                  id: event.data.id,
                   name: event.data.name,
                   state: { status: "streaming", input: "" },
                   time: { created: event.created },
@@ -255,17 +255,17 @@ export function createV2SessionReducer() {
               ],
         }))
       case "session.tool.input.delta":
-        return updateTool(source, event.data.assistantMessageID, event.data.callID, sessionID, (tool) =>
+        return updateTool(source, event.data.assistantMessageID, event.data.id, sessionID, (tool) =>
           tool.state.status === "streaming"
             ? { ...tool, state: { ...tool.state, input: tool.state.input + event.data.delta } }
             : tool,
         )
       case "session.tool.input.ended":
-        return updateTool(source, event.data.assistantMessageID, event.data.callID, sessionID, (tool) =>
+        return updateTool(source, event.data.assistantMessageID, event.data.id, sessionID, (tool) =>
           tool.state.status === "streaming" ? { ...tool, state: { ...tool.state, input: event.data.text } } : tool,
         )
       case "session.tool.called":
-        return updateTool(source, event.data.assistantMessageID, event.data.callID, sessionID, (tool) => ({
+        return updateTool(source, event.data.assistantMessageID, event.data.id, sessionID, (tool) => ({
           ...tool,
           executed: event.data.executed,
           providerState: event.data.state,
@@ -274,7 +274,7 @@ export function createV2SessionReducer() {
           time: { ...tool.time, ran: event.created },
         }))
       case "session.tool.progress":
-        return updateTool(source, event.data.assistantMessageID, event.data.callID, sessionID, (tool) =>
+        return updateTool(source, event.data.assistantMessageID, event.data.id, sessionID, (tool) =>
           tool.state.status === "running"
             ? {
                 ...tool,
@@ -284,7 +284,7 @@ export function createV2SessionReducer() {
             : tool,
         )
       case "session.tool.success":
-        return updateTool(source, event.data.assistantMessageID, event.data.callID, sessionID, (tool) => {
+        return updateTool(source, event.data.assistantMessageID, event.data.id, sessionID, (tool) => {
           if (tool.state.status !== "running") return tool
           return {
             ...tool,
@@ -302,7 +302,7 @@ export function createV2SessionReducer() {
           }
         })
       case "session.tool.failed":
-        return updateTool(source, event.data.assistantMessageID, event.data.callID, sessionID, (tool) => {
+        return updateTool(source, event.data.assistantMessageID, event.data.id, sessionID, (tool) => {
           if (tool.state.status !== "streaming" && tool.state.status !== "running") return tool
           return {
             ...tool,

packages/cli/src/run/noninteractive.ts

@@ -470,7 +470,7 @@ export async function runNonInteractivePrompt(input: Input) {
       if (event.type === "session.step.failed") {
         if (
           input.compatibility === "v1" &&
-          event.data.error.message === "Provider stream ended without a terminal finish event"
+          event.data.error.message === "The provider response ended unexpectedly."
         ) {
           pendingStep = undefined
           v1InvalidOutput = true

packages/cli/test/run/noninteractive.test.ts

@@ -503,8 +503,8 @@ describe("runNonInteractivePrompt", () => {
       turn: (messageID) => [
         prompted(messageID),
         stepStarted(),
-        stepFailed("Provider stream ended without a terminal finish event"),
-        executionFailed("Provider stream ended without a terminal finish event"),
+        stepFailed("The provider response ended unexpectedly."),
+        executionFailed("The provider response ended unexpectedly."),
       ],
     })
 

packages/core/src/session/runner/retry.ts

@@ -20,10 +20,11 @@ export function isRetryable(error: AIError) {
     case "ProviderInternal":
     case "Transport":
       return true
+    case "InvalidProviderOutput":
+      return error.reason.classification === "incomplete-stream"
     case "Authentication":
     case "QuotaExceeded":
     case "ContentPolicy":
-    case "InvalidProviderOutput":
     case "InvalidRequest":
     case "NoRoute":
     case "UnknownProvider":

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

@@ -513,6 +513,16 @@ const providerUnavailable = () =>
     reason: new TransportReason({ message: "Provider unavailable" }),
   })
 
+const incompleteStream = () =>
+  new AIError({
+    module: "test",
+    method: "stream",
+    reason: new InvalidProviderOutputReason({
+      classification: "incomplete-stream",
+      message: "The provider response ended unexpectedly.",
+    }),
+  })
+
 const invalidRequest = () =>
   new AIError({
     module: "test",
@@ -3949,6 +3959,26 @@ describe("SessionRunnerLLM", () => {
     }),
   )
 
+  it.effect("retries an incomplete stream before output", () =>
+    Effect.gen(function* () {
+      const session = yield* setup
+      yield* admit(session, "Retry incomplete stream")
+      yield* TestLLM.push(Stream.fail(incompleteStream()))
+      yield* TestLLM.push(TestLLM.text("Recovered", "incomplete-stream-success"))
+
+      const run = yield* session.resume(sessionID).pipe(Effect.forkChild)
+      yield* TestLLM.wait(1)
+      yield* TestClock.adjust("2 seconds")
+      yield* Fiber.join(run)
+
+      expect(requests).toHaveLength(2)
+      expect(yield* session.context(sessionID)).toMatchObject([
+        { type: "user" },
+        { type: "assistant", finish: "stop", content: [{ type: "text", text: "Recovered" }] },
+      ])
+    }),
+  )
+
   it.effect("uses a larger provider retry-after delay", () =>
     Effect.gen(function* () {
       const session = yield* setup
@@ -3969,7 +3999,7 @@ describe("SessionRunnerLLM", () => {
   it.effect("does not retry eligible failures after observable output", () =>
     Effect.gen(function* () {
       const session = yield* setup
-      const failure = rateLimited()
+      const failure = incompleteStream()
       yield* TestLLM.push(
         TestLLM.failAfter(
           failure,
@@ -3987,7 +4017,7 @@ describe("SessionRunnerLLM", () => {
         {
           type: "assistant",
           finish: "error",
-          error: { type: "provider.rate-limit" },
+          error: { type: "provider.invalid-output" },
           content: [{ type: "text", text: "Partial" }],
         },
       ])