refactor(session): effectify SessionPrompt service (#19483)

packages/opencode/test/session/compaction.test.ts

@@ -129,7 +129,7 @@ async function tool(sessionID: SessionID, messageID: MessageID, tool: string, ou
 }
 
 function fake(
-  input: Parameters<(typeof SessionProcessorModule.SessionProcessor)["create"]>[0],
+  input: Parameters<SessionProcessorModule.SessionProcessor.Interface["create"]>[0],
   result: "continue" | "compact",
 ) {
   const msg = input.assistantMessage
@@ -540,7 +540,6 @@ describe("session.compaction.process", () => {
                 parentID: msg.id,
                 messages: msgs,
                 sessionID: session.id,
-                abort: new AbortController().signal,
                 auto: false,
               }),
             ),
@@ -580,7 +579,6 @@ describe("session.compaction.process", () => {
                 parentID: msg.id,
                 messages: msgs,
                 sessionID: session.id,
-                abort: new AbortController().signal,
                 auto: false,
               }),
             ),
@@ -621,7 +619,6 @@ describe("session.compaction.process", () => {
                 parentID: msg.id,
                 messages: msgs,
                 sessionID: session.id,
-                abort: new AbortController().signal,
                 auto: true,
               }),
             ),
@@ -675,7 +672,6 @@ describe("session.compaction.process", () => {
                 parentID: msg.id,
                 messages: msgs,
                 sessionID: session.id,
-                abort: new AbortController().signal,
                 auto: true,
                 overflow: true,
               }),
@@ -717,7 +713,6 @@ describe("session.compaction.process", () => {
                 parentID: msg.id,
                 messages: msgs,
                 sessionID: session.id,
-                abort: new AbortController().signal,
                 auto: true,
                 overflow: true,
               }),
@@ -792,7 +787,6 @@ describe("session.compaction.process", () => {
                   parentID: msg.id,
                   messages: msgs,
                   sessionID: session.id,
-                  abort: abort.signal,
                   auto: false,
                 }),
               ),
@@ -858,7 +852,6 @@ describe("session.compaction.process", () => {
                   parentID: msg.id,
                   messages: msgs,
                   sessionID: session.id,
-                  abort: abort.signal,
                   auto: false,
                 }),
               ),
@@ -892,6 +885,91 @@ describe("session.compaction.process", () => {
       },
     })
   })
+
+  test("does not allow tool calls while generating the summary", async () => {
+    const stub = llm()
+    stub.push(
+      Stream.make(
+        { type: "start" } satisfies LLM.Event,
+        { type: "tool-input-start", id: "call-1", toolName: "_noop" } satisfies LLM.Event,
+        { type: "tool-call", toolCallId: "call-1", toolName: "_noop", input: {} } satisfies LLM.Event,
+        {
+          type: "finish-step",
+          finishReason: "tool-calls",
+          rawFinishReason: "tool_calls",
+          response: { id: "res", modelId: "test-model", timestamp: new Date() },
+          providerMetadata: undefined,
+          usage: {
+            inputTokens: 1,
+            outputTokens: 1,
+            totalTokens: 2,
+            inputTokenDetails: {
+              noCacheTokens: undefined,
+              cacheReadTokens: undefined,
+              cacheWriteTokens: undefined,
+            },
+            outputTokenDetails: {
+              textTokens: undefined,
+              reasoningTokens: undefined,
+            },
+          },
+        } satisfies LLM.Event,
+        {
+          type: "finish",
+          finishReason: "tool-calls",
+          rawFinishReason: "tool_calls",
+          totalUsage: {
+            inputTokens: 1,
+            outputTokens: 1,
+            totalTokens: 2,
+            inputTokenDetails: {
+              noCacheTokens: undefined,
+              cacheReadTokens: undefined,
+              cacheWriteTokens: undefined,
+            },
+            outputTokenDetails: {
+              textTokens: undefined,
+              reasoningTokens: undefined,
+            },
+          },
+        } satisfies LLM.Event,
+      ),
+    )
+
+    await using tmp = await tmpdir({ git: true })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        spyOn(ProviderModule.Provider, "getModel").mockResolvedValue(createModel({ context: 100_000, output: 32_000 }))
+
+        const session = await Session.create({})
+        const msg = await user(session.id, "hello")
+        const rt = liveRuntime(stub.layer)
+        try {
+          const msgs = await Session.messages({ sessionID: session.id })
+          await rt.runPromise(
+            SessionCompaction.Service.use((svc) =>
+              svc.process({
+                parentID: msg.id,
+                messages: msgs,
+                sessionID: session.id,
+                auto: false,
+              }),
+            ),
+          )
+
+          const summary = (await Session.messages({ sessionID: session.id })).find(
+            (item) => item.info.role === "assistant" && item.info.summary,
+          )
+
+          expect(summary?.info.role).toBe("assistant")
+          expect(summary?.parts.some((part) => part.type === "tool")).toBe(false)
+        } finally {
+          await rt.dispose()
+        }
+      },
+    })
+  })
 })
 
 describe("util.token.estimate", () => {

packages/opencode/test/session/llm.test.ts

@@ -1,7 +1,9 @@
 import { afterAll, beforeAll, beforeEach, describe, expect, test } from "bun:test"
 import path from "path"
 import { tool, type ModelMessage } from "ai"
+import { Cause, Exit, Stream } from "effect"
 import z from "zod"
+import { makeRuntime } from "../../src/effect/run-service"
 import { LLM } from "../../src/session/llm"
 import { Instance } from "../../src/project/instance"
 import { Provider } from "../../src/provider/provider"
@@ -109,7 +111,11 @@ type Capture = {
 
 const state = {
   server: null as ReturnType<typeof Bun.serve> | null,
-  queue: [] as Array<{ path: string; response: Response; resolve: (value: Capture) => void }>,
+  queue: [] as Array<{
+    path: string
+    response: Response | ((req: Request, capture: Capture) => Response)
+    resolve: (value: Capture) => void
+  }>,
 }
 
 function deferred<T>() {
@@ -126,6 +132,58 @@ function waitRequest(pathname: string, response: Response) {
   return pending.promise
 }
 
+function timeout(ms: number) {
+  return new Promise<never>((_, reject) => {
+    setTimeout(() => reject(new Error(`timed out after ${ms}ms`)), ms)
+  })
+}
+
+function waitStreamingRequest(pathname: string) {
+  const request = deferred<Capture>()
+  const requestAborted = deferred<void>()
+  const responseCanceled = deferred<void>()
+  const encoder = new TextEncoder()
+
+  state.queue.push({
+    path: pathname,
+    resolve: request.resolve,
+    response(req: Request) {
+      req.signal.addEventListener("abort", () => requestAborted.resolve(), { once: true })
+
+      return new Response(
+        new ReadableStream<Uint8Array>({
+          start(controller) {
+            controller.enqueue(
+              encoder.encode(
+                [
+                  `data: ${JSON.stringify({
+                    id: "chatcmpl-abort",
+                    object: "chat.completion.chunk",
+                    choices: [{ delta: { role: "assistant" } }],
+                  })}`,
+                ].join("\n\n") + "\n\n",
+              ),
+            )
+          },
+          cancel() {
+            responseCanceled.resolve()
+          },
+        }),
+        {
+          status: 200,
+          headers: { "Content-Type": "text/event-stream" },
+        },
+      )
+    },
+  })
+
+  return {
+    request: request.promise,
+    requestAborted: requestAborted.promise,
+    responseCanceled: responseCanceled.promise,
+  }
+}
+
 beforeAll(() => {
   state.server = Bun.serve({
     port: 0,
@@ -143,7 +201,9 @@ beforeAll(() => {
         return new Response("not found", { status: 404 })
       }
 
-      return next.response
+      return typeof next.response === "function"
+        ? next.response(req, { url, headers: req.headers, body })
+        : next.response
     },
   })
 })
@@ -325,6 +385,162 @@ describe("session.llm.stream", () => {
     })
   })
 
+  test("raw stream abort signal cancels provider response body promptly", async () => {
+    const server = state.server
+    if (!server) throw new Error("Server not initialized")
+
+    const providerID = "alibaba"
+    const modelID = "qwen-plus"
+    const fixture = await loadFixture(providerID, modelID)
+    const model = fixture.model
+    const pending = waitStreamingRequest("/chat/completions")
+
+    await using tmp = await tmpdir({
+      init: async (dir) => {
+        await Bun.write(
+          path.join(dir, "opencode.json"),
+          JSON.stringify({
+            $schema: "https://opencode.ai/config.json",
+            enabled_providers: [providerID],
+            provider: {
+              [providerID]: {
+                options: {
+                  apiKey: "test-key",
+                  baseURL: `${server.url.origin}/v1`,
+                },
+              },
+            },
+          }),
+        )
+      },
+    })
+
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const resolved = await Provider.getModel(ProviderID.make(providerID), ModelID.make(model.id))
+        const sessionID = SessionID.make("session-test-raw-abort")
+        const agent = {
+          name: "test",
+          mode: "primary",
+          options: {},
+          permission: [{ permission: "*", pattern: "*", action: "allow" }],
+        } satisfies Agent.Info
+        const user = {
+          id: MessageID.make("user-raw-abort"),
+          sessionID,
+          role: "user",
+          time: { created: Date.now() },
+          agent: agent.name,
+          model: { providerID: ProviderID.make(providerID), modelID: resolved.id },
+        } satisfies MessageV2.User
+
+        const ctrl = new AbortController()
+        const result = await LLM.stream({
+          user,
+          sessionID,
+          model: resolved,
+          agent,
+          system: ["You are a helpful assistant."],
+          abort: ctrl.signal,
+          messages: [{ role: "user", content: "Hello" }],
+          tools: {},
+        })
+
+        const iter = result.fullStream[Symbol.asyncIterator]()
+        await pending.request
+        await iter.next()
+        ctrl.abort()
+
+        await Promise.race([pending.responseCanceled, timeout(500)])
+        await Promise.race([pending.requestAborted, timeout(500)]).catch(() => undefined)
+        await iter.return?.()
+      },
+    })
+  })
+
+  test("service stream cancellation cancels provider response body promptly", async () => {
+    const server = state.server
+    if (!server) throw new Error("Server not initialized")
+
+    const providerID = "alibaba"
+    const modelID = "qwen-plus"
+    const fixture = await loadFixture(providerID, modelID)
+    const model = fixture.model
+    const pending = waitStreamingRequest("/chat/completions")
+
+    await using tmp = await tmpdir({
+      init: async (dir) => {
+        await Bun.write(
+          path.join(dir, "opencode.json"),
+          JSON.stringify({
+            $schema: "https://opencode.ai/config.json",
+            enabled_providers: [providerID],
+            provider: {
+              [providerID]: {
+                options: {
+                  apiKey: "test-key",
+                  baseURL: `${server.url.origin}/v1`,
+                },
+              },
+            },
+          }),
+        )
+      },
+    })
+
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const resolved = await Provider.getModel(ProviderID.make(providerID), ModelID.make(model.id))
+        const sessionID = SessionID.make("session-test-service-abort")
+        const agent = {
+          name: "test",
+          mode: "primary",
+          options: {},
+          permission: [{ permission: "*", pattern: "*", action: "allow" }],
+        } satisfies Agent.Info
+        const user = {
+          id: MessageID.make("user-service-abort"),
+          sessionID,
+          role: "user",
+          time: { created: Date.now() },
+          agent: agent.name,
+          model: { providerID: ProviderID.make(providerID), modelID: resolved.id },
+        } satisfies MessageV2.User
+
+        const ctrl = new AbortController()
+        const { runPromiseExit } = makeRuntime(LLM.Service, LLM.defaultLayer)
+        const run = runPromiseExit(
+          (svc) =>
+            svc
+              .stream({
+                user,
+                sessionID,
+                model: resolved,
+                agent,
+                system: ["You are a helpful assistant."],
+                messages: [{ role: "user", content: "Hello" }],
+                tools: {},
+              })
+              .pipe(Stream.runDrain),
+          { signal: ctrl.signal },
+        )
+
+        await pending.request
+        ctrl.abort()
+
+        await Promise.race([pending.responseCanceled, timeout(500)])
+        const exit = await run
+        expect(Exit.isFailure(exit)).toBe(true)
+        if (Exit.isFailure(exit)) {
+          expect(Cause.hasInterrupts(exit.cause)).toBe(true)
+        }
+        await Promise.race([pending.requestAborted, timeout(500)]).catch(() => undefined)
+      },
+    })
+  })
+
   test("keeps tools enabled by prompt permissions", async () => {
     const server = state.server
     if (!server) {

packages/opencode/test/session/processor-effect.test.ts

@@ -1,7 +1,7 @@
 import { NodeFileSystem } from "@effect/platform-node"
 import { expect } from "bun:test"
 import { APICallError } from "ai"
-import { Effect, Layer, ServiceMap } from "effect"
+import { Cause, Effect, Exit, Fiber, Layer, ServiceMap } from "effect"
 import * as Stream from "effect/Stream"
 import path from "path"
 import type { Agent } from "../../src/agent/agent"
@@ -10,7 +10,6 @@ import { Bus } from "../../src/bus"
 import { Config } from "../../src/config/config"
 import { Permission } from "../../src/permission"
 import { Plugin } from "../../src/plugin"
-import { Instance } from "../../src/project/instance"
 import type { Provider } from "../../src/provider/provider"
 import { ModelID, ProviderID } from "../../src/provider/schema"
 import { Session } from "../../src/session"
@@ -120,21 +119,8 @@ function fail<E>(err: E, ...items: LLM.Event[]) {
   return stream(...items).pipe(Stream.concat(Stream.fail(err)))
 }
 
-function wait(abort: AbortSignal) {
-  return Effect.promise(
-    () =>
-      new Promise<void>((done) => {
-        abort.addEventListener("abort", () => done(), { once: true })
-      }),
-  )
-}
-
-function hang(input: LLM.StreamInput, ...items: LLM.Event[]) {
-  return stream(...items).pipe(
-    Stream.concat(
-      Stream.unwrap(wait(input.abort).pipe(Effect.as(Stream.fail(new DOMException("Aborted", "AbortError"))))),
-    ),
-  )
+function hang(_input: LLM.StreamInput, ...items: LLM.Event[]) {
+  return stream(...items).pipe(Stream.concat(Stream.fromEffect(Effect.never)))
 }
 
 function model(context: number): Provider.Model {
@@ -291,13 +277,11 @@ it.effect("session.processor effect tests capture llm input cleanly", () => {
         const chat = yield* session.create({})
         const parent = yield* user(chat.id, "hi")
         const msg = yield* assistant(chat.id, parent.id, path.resolve(dir))
-        const abort = new AbortController()
         const mdl = model(100)
         const handle = yield* processors.create({
           assistantMessage: msg,
           sessionID: chat.id,
           model: mdl,
-          abort: abort.signal,
         })
 
         const input = {
@@ -313,7 +297,6 @@ it.effect("session.processor effect tests capture llm input cleanly", () => {
           model: mdl,
           agent: agent(),
           system: [],
-          abort: abort.signal,
           messages: [{ role: "user", content: "hi" }],
           tools: {},
         } satisfies LLM.StreamInput
@@ -359,13 +342,11 @@ it.effect("session.processor effect tests stop after token overflow requests com
         const chat = yield* session.create({})
         const parent = yield* user(chat.id, "compact")
         const msg = yield* assistant(chat.id, parent.id, path.resolve(dir))
-        const abort = new AbortController()
         const mdl = model(20)
         const handle = yield* processors.create({
           assistantMessage: msg,
           sessionID: chat.id,
           model: mdl,
-          abort: abort.signal,
         })
 
         const value = yield* handle.process({
@@ -381,7 +362,6 @@ it.effect("session.processor effect tests stop after token overflow requests com
           model: mdl,
           agent: agent(),
           system: [],
-          abort: abort.signal,
           messages: [{ role: "user", content: "compact" }],
           tools: {},
         })
@@ -433,13 +413,11 @@ it.effect("session.processor effect tests reset reasoning state across retries",
         const chat = yield* session.create({})
         const parent = yield* user(chat.id, "reason")
         const msg = yield* assistant(chat.id, parent.id, path.resolve(dir))
-        const abort = new AbortController()
         const mdl = model(100)
         const handle = yield* processors.create({
           assistantMessage: msg,
           sessionID: chat.id,
           model: mdl,
-          abort: abort.signal,
         })
 
         const value = yield* handle.process({
@@ -455,7 +433,6 @@ it.effect("session.processor effect tests reset reasoning state across retries",
           model: mdl,
           agent: agent(),
           system: [],
-          abort: abort.signal,
           messages: [{ role: "user", content: "reason" }],
           tools: {},
         })
@@ -485,13 +462,11 @@ it.effect("session.processor effect tests do not retry unknown json errors", ()
         const chat = yield* session.create({})
         const parent = yield* user(chat.id, "json")
         const msg = yield* assistant(chat.id, parent.id, path.resolve(dir))
-        const abort = new AbortController()
         const mdl = model(100)
         const handle = yield* processors.create({
           assistantMessage: msg,
           sessionID: chat.id,
           model: mdl,
-          abort: abort.signal,
         })
 
         const value = yield* handle.process({
@@ -507,7 +482,6 @@ it.effect("session.processor effect tests do not retry unknown json errors", ()
           model: mdl,
           agent: agent(),
           system: [],
-          abort: abort.signal,
           messages: [{ role: "user", content: "json" }],
           tools: {},
         })
@@ -535,13 +509,11 @@ it.effect("session.processor effect tests retry recognized structured json error
         const chat = yield* session.create({})
         const parent = yield* user(chat.id, "retry json")
         const msg = yield* assistant(chat.id, parent.id, path.resolve(dir))
-        const abort = new AbortController()
         const mdl = model(100)
         const handle = yield* processors.create({
           assistantMessage: msg,
           sessionID: chat.id,
           model: mdl,
-          abort: abort.signal,
         })
 
         const value = yield* handle.process({
@@ -557,7 +529,6 @@ it.effect("session.processor effect tests retry recognized structured json error
           model: mdl,
           agent: agent(),
           system: [],
-          abort: abort.signal,
           messages: [{ role: "user", content: "retry json" }],
           tools: {},
         })
@@ -601,7 +572,6 @@ it.effect("session.processor effect tests publish retry status updates", () => {
         const chat = yield* session.create({})
         const parent = yield* user(chat.id, "retry")
         const msg = yield* assistant(chat.id, parent.id, path.resolve(dir))
-        const abort = new AbortController()
         const mdl = model(100)
         const states: number[] = []
         const off = yield* bus.subscribeCallback(SessionStatus.Event.Status, (evt) => {
@@ -612,7 +582,6 @@ it.effect("session.processor effect tests publish retry status updates", () => {
           assistantMessage: msg,
           sessionID: chat.id,
           model: mdl,
-          abort: abort.signal,
         })
 
         const value = yield* handle.process({
@@ -628,7 +597,6 @@ it.effect("session.processor effect tests publish retry status updates", () => {
           model: mdl,
           agent: agent(),
           system: [],
-          abort: abort.signal,
           messages: [{ role: "user", content: "retry" }],
           tools: {},
         })
@@ -656,13 +624,11 @@ it.effect("session.processor effect tests compact on structured context overflow
         const chat = yield* session.create({})
         const parent = yield* user(chat.id, "compact json")
         const msg = yield* assistant(chat.id, parent.id, path.resolve(dir))
-        const abort = new AbortController()
         const mdl = model(100)
         const handle = yield* processors.create({
           assistantMessage: msg,
           sessionID: chat.id,
           model: mdl,
-          abort: abort.signal,
         })
 
         const value = yield* handle.process({
@@ -678,7 +644,6 @@ it.effect("session.processor effect tests compact on structured context overflow
           model: mdl,
           agent: agent(),
           system: [],
-          abort: abort.signal,
           messages: [{ role: "user", content: "compact json" }],
           tools: {},
         })
@@ -696,7 +661,6 @@ it.effect("session.processor effect tests mark pending tools as aborted on clean
     (dir) =>
       Effect.gen(function* () {
         const ready = defer<void>()
-        const seen = defer<void>()
         const test = yield* TestLLM
         const processors = yield* SessionProcessor.Service
         const session = yield* Session.Service
@@ -710,17 +674,15 @@ it.effect("session.processor effect tests mark pending tools as aborted on clean
         const chat = yield* session.create({})
         const parent = yield* user(chat.id, "tool abort")
         const msg = yield* assistant(chat.id, parent.id, path.resolve(dir))
-        const abort = new AbortController()
         const mdl = model(100)
         const handle = yield* processors.create({
           assistantMessage: msg,
           sessionID: chat.id,
           model: mdl,
-          abort: abort.signal,
         })
 
-        const run = Effect.runPromise(
-          handle.process({
+        const run = yield* handle
+          .process({
             user: {
               id: parent.id,
               sessionID: chat.id,
@@ -733,20 +695,25 @@ it.effect("session.processor effect tests mark pending tools as aborted on clean
             model: mdl,
             agent: agent(),
             system: [],
-            abort: abort.signal,
             messages: [{ role: "user", content: "tool abort" }],
             tools: {},
-          }),
-        )
+          })
+          .pipe(Effect.forkChild)
 
         yield* Effect.promise(() => ready.promise)
-        abort.abort()
+        yield* Fiber.interrupt(run)
 
-        const value = yield* Effect.promise(() => run)
+        const exit = yield* Fiber.await(run)
+        if (Exit.isFailure(exit) && Cause.hasInterruptsOnly(exit.cause)) {
+          yield* handle.abort()
+        }
         const parts = yield* Effect.promise(() => MessageV2.parts(msg.id))
         const tool = parts.find((part): part is MessageV2.ToolPart => part.type === "tool")
 
-        expect(value).toBe("stop")
+        expect(Exit.isFailure(exit)).toBe(true)
+        if (Exit.isFailure(exit)) {
+          expect(Cause.hasInterruptsOnly(exit.cause)).toBe(true)
+        }
         expect(yield* test.calls).toBe(1)
         expect(tool?.state.status).toBe("error")
         if (tool?.state.status === "error") {
@@ -779,7 +746,6 @@ it.effect("session.processor effect tests record aborted errors and idle state",
         const chat = yield* session.create({})
         const parent = yield* user(chat.id, "abort")
         const msg = yield* assistant(chat.id, parent.id, path.resolve(dir))
-        const abort = new AbortController()
         const mdl = model(100)
         const errs: string[] = []
         const off = yield* bus.subscribeCallback(Session.Event.Error, (evt) => {
@@ -792,11 +758,10 @@ it.effect("session.processor effect tests record aborted errors and idle state",
           assistantMessage: msg,
           sessionID: chat.id,
           model: mdl,
-          abort: abort.signal,
         })
 
-        const run = Effect.runPromise(
-          handle.process({
+        const run = yield* handle
+          .process({
             user: {
               id: parent.id,
               sessionID: chat.id,
@@ -809,22 +774,27 @@ it.effect("session.processor effect tests record aborted errors and idle state",
             model: mdl,
             agent: agent(),
             system: [],
-            abort: abort.signal,
             messages: [{ role: "user", content: "abort" }],
             tools: {},
-          }),
-        )
+          })
+          .pipe(Effect.forkChild)
 
         yield* Effect.promise(() => ready.promise)
-        abort.abort()
+        yield* Fiber.interrupt(run)
 
-        const value = yield* Effect.promise(() => run)
+        const exit = yield* Fiber.await(run)
+        if (Exit.isFailure(exit) && Cause.hasInterruptsOnly(exit.cause)) {
+          yield* handle.abort()
+        }
         yield* Effect.promise(() => seen.promise)
         const stored = yield* Effect.promise(() => MessageV2.get({ sessionID: chat.id, messageID: msg.id }))
         const state = yield* status.get(chat.id)
         off()
 
-        expect(value).toBe("stop")
+        expect(Exit.isFailure(exit)).toBe(true)
+        if (Exit.isFailure(exit)) {
+          expect(Cause.hasInterruptsOnly(exit.cause)).toBe(true)
+        }
         expect(handle.message.error?.name).toBe("MessageAbortedError")
         expect(stored.info.role).toBe("assistant")
         if (stored.info.role === "assistant") {
@@ -836,3 +806,67 @@ it.effect("session.processor effect tests record aborted errors and idle state",
     { git: true },
   )
 })
+
+it.effect("session.processor effect tests mark interruptions aborted without manual abort", () => {
+  return provideTmpdirInstance(
+    (dir) =>
+      Effect.gen(function* () {
+        const ready = defer<void>()
+        const processors = yield* SessionProcessor.Service
+        const session = yield* Session.Service
+        const status = yield* SessionStatus.Service
+        const test = yield* TestLLM
+
+        yield* test.push((input) =>
+          hang(input, start()).pipe(
+            Stream.tap((event) => (event.type === "start" ? Effect.sync(() => ready.resolve()) : Effect.void)),
+          ),
+        )
+
+        const chat = yield* session.create({})
+        const parent = yield* user(chat.id, "interrupt")
+        const msg = yield* assistant(chat.id, parent.id, path.resolve(dir))
+        const mdl = model(100)
+        const handle = yield* processors.create({
+          assistantMessage: msg,
+          sessionID: chat.id,
+          model: mdl,
+        })
+
+        const run = yield* handle
+          .process({
+            user: {
+              id: parent.id,
+              sessionID: chat.id,
+              role: "user",
+              time: parent.time,
+              agent: parent.agent,
+              model: { providerID: ref.providerID, modelID: ref.modelID },
+            } satisfies MessageV2.User,
+            sessionID: chat.id,
+            model: mdl,
+            agent: agent(),
+            system: [],
+            messages: [{ role: "user", content: "interrupt" }],
+            tools: {},
+          })
+          .pipe(Effect.forkChild)
+
+        yield* Effect.promise(() => ready.promise)
+        yield* Fiber.interrupt(run)
+
+        const exit = yield* Fiber.await(run)
+        const stored = yield* Effect.promise(() => MessageV2.get({ sessionID: chat.id, messageID: msg.id }))
+        const state = yield* status.get(chat.id)
+
+        expect(Exit.isFailure(exit)).toBe(true)
+        expect(handle.message.error?.name).toBe("MessageAbortedError")
+        expect(stored.info.role).toBe("assistant")
+        if (stored.info.role === "assistant") {
+          expect(stored.info.error?.name).toBe("MessageAbortedError")
+        }
+        expect(state).toMatchObject({ type: "idle" })
+      }),
+    { git: true },
+  )
+})

packages/opencode/test/session/prompt-concurrency.test.ts

@@ -0,0 +1,247 @@
+import { describe, expect, spyOn, test } from "bun:test"
+import { Instance } from "../../src/project/instance"
+import { Provider } from "../../src/provider/provider"
+import { Session } from "../../src/session"
+import { MessageV2 } from "../../src/session/message-v2"
+import { SessionPrompt } from "../../src/session/prompt"
+import { SessionStatus } from "../../src/session/status"
+import { MessageID, PartID, SessionID } from "../../src/session/schema"
+import { Log } from "../../src/util/log"
+import { tmpdir } from "../fixture/fixture"
+
+Log.init({ print: false })
+
+function deferred() {
+  let resolve!: () => void
+  const promise = new Promise<void>((done) => {
+    resolve = done
+  })
+  return { promise, resolve }
+}
+
+// Helper: seed a session with a user message + finished assistant message
+// so loop() exits immediately without calling any LLM
+async function seed(sessionID: SessionID) {
+  const userMsg: MessageV2.Info = {
+    id: MessageID.ascending(),
+    role: "user",
+    sessionID,
+    time: { created: Date.now() },
+    agent: "build",
+    model: { providerID: "openai" as any, modelID: "gpt-5.2" as any },
+  }
+  await Session.updateMessage(userMsg)
+  await Session.updatePart({
+    id: PartID.ascending(),
+    messageID: userMsg.id,
+    sessionID,
+    type: "text",
+    text: "hello",
+  })
+
+  const assistantMsg: MessageV2.Info = {
+    id: MessageID.ascending(),
+    role: "assistant",
+    parentID: userMsg.id,
+    sessionID,
+    mode: "build",
+    agent: "build",
+    cost: 0,
+    path: { cwd: "/tmp", root: "/tmp" },
+    tokens: { input: 0, output: 0, reasoning: 0, cache: { read: 0, write: 0 } },
+    modelID: "gpt-5.2" as any,
+    providerID: "openai" as any,
+    time: { created: Date.now(), completed: Date.now() },
+    finish: "stop",
+  }
+  await Session.updateMessage(assistantMsg)
+  await Session.updatePart({
+    id: PartID.ascending(),
+    messageID: assistantMsg.id,
+    sessionID,
+    type: "text",
+    text: "hi there",
+  })
+
+  return { userMsg, assistantMsg }
+}
+
+describe("session.prompt concurrency", () => {
+  test("loop returns assistant message and sets status to idle", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const session = await Session.create({})
+        await seed(session.id)
+
+        const result = await SessionPrompt.loop({ sessionID: session.id })
+        expect(result.info.role).toBe("assistant")
+        if (result.info.role === "assistant") expect(result.info.finish).toBe("stop")
+
+        const status = await SessionStatus.get(session.id)
+        expect(status.type).toBe("idle")
+      },
+    })
+  })
+
+  test("concurrent loop callers get the same result", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const session = await Session.create({})
+        await seed(session.id)
+
+        const [a, b] = await Promise.all([
+          SessionPrompt.loop({ sessionID: session.id }),
+          SessionPrompt.loop({ sessionID: session.id }),
+        ])
+
+        expect(a.info.id).toBe(b.info.id)
+        expect(a.info.role).toBe("assistant")
+      },
+    })
+  })
+
+  test("assertNotBusy throws when loop is running", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const session = await Session.create({})
+        const userMsg: MessageV2.Info = {
+          id: MessageID.ascending(),
+          role: "user",
+          sessionID: session.id,
+          time: { created: Date.now() },
+          agent: "build",
+          model: { providerID: "openai" as any, modelID: "gpt-5.2" as any },
+        }
+        await Session.updateMessage(userMsg)
+        await Session.updatePart({
+          id: PartID.ascending(),
+          messageID: userMsg.id,
+          sessionID: session.id,
+          type: "text",
+          text: "hello",
+        })
+
+        const ready = deferred()
+        const gate = deferred()
+        const getModel = spyOn(Provider, "getModel").mockImplementation(async () => {
+          ready.resolve()
+          await gate.promise
+          throw new Error("test stop")
+        })
+
+        try {
+          const loopPromise = SessionPrompt.loop({ sessionID: session.id }).catch(() => undefined)
+          await ready.promise
+
+          await expect(SessionPrompt.assertNotBusy(session.id)).rejects.toBeInstanceOf(Session.BusyError)
+
+          gate.resolve()
+          await loopPromise
+        } finally {
+          gate.resolve()
+          getModel.mockRestore()
+        }
+
+        // After loop completes, assertNotBusy should succeed
+        await SessionPrompt.assertNotBusy(session.id)
+      },
+    })
+  })
+
+  test("cancel sets status to idle", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const session = await Session.create({})
+        // Seed only a user message — loop must call getModel to proceed
+        const userMsg: MessageV2.Info = {
+          id: MessageID.ascending(),
+          role: "user",
+          sessionID: session.id,
+          time: { created: Date.now() },
+          agent: "build",
+          model: { providerID: "openai" as any, modelID: "gpt-5.2" as any },
+        }
+        await Session.updateMessage(userMsg)
+        await Session.updatePart({
+          id: PartID.ascending(),
+          messageID: userMsg.id,
+          sessionID: session.id,
+          type: "text",
+          text: "hello",
+        })
+        // Also seed an assistant message so lastAssistant() fallback can find it
+        const assistantMsg: MessageV2.Info = {
+          id: MessageID.ascending(),
+          role: "assistant",
+          parentID: userMsg.id,
+          sessionID: session.id,
+          mode: "build",
+          agent: "build",
+          cost: 0,
+          path: { cwd: "/tmp", root: "/tmp" },
+          tokens: { input: 0, output: 0, reasoning: 0, cache: { read: 0, write: 0 } },
+          modelID: "gpt-5.2" as any,
+          providerID: "openai" as any,
+          time: { created: Date.now() },
+        }
+        await Session.updateMessage(assistantMsg)
+        await Session.updatePart({
+          id: PartID.ascending(),
+          messageID: assistantMsg.id,
+          sessionID: session.id,
+          type: "text",
+          text: "hi there",
+        })
+
+        const ready = deferred()
+        const gate = deferred()
+        const getModel = spyOn(Provider, "getModel").mockImplementation(async () => {
+          ready.resolve()
+          await gate.promise
+          throw new Error("test stop")
+        })
+
+        try {
+          // Start loop — it will block in getModel (assistant has no finish, so loop continues)
+          const loopPromise = SessionPrompt.loop({ sessionID: session.id })
+
+          await ready.promise
+
+          await SessionPrompt.cancel(session.id)
+
+          const status = await SessionStatus.get(session.id)
+          expect(status.type).toBe("idle")
+
+          // loop should resolve cleanly, not throw "All fibers interrupted"
+          const result = await loopPromise
+          expect(result.info.role).toBe("assistant")
+          expect(result.info.id).toBe(assistantMsg.id)
+        } finally {
+          gate.resolve()
+          getModel.mockRestore()
+        }
+      },
+    })
+  }, 10000)
+
+  test("cancel on idle session just sets idle", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const session = await Session.create({})
+        await SessionPrompt.cancel(session.id)
+        const status = await SessionStatus.get(session.id)
+        expect(status.type).toBe("idle")
+      },
+    })
+  })
+})