refactor(core): share subagent job execution with recovery

packages/core/src/session/error.ts

@@ -74,15 +74,6 @@ export class StepFailedError extends Schema.TaggedError<StepFailedError>()("Sess
   }
 }
 
-export class UserInterruptedError extends Schema.TaggedError<UserInterruptedError>()(
-  "Session.UserInterruptedError",
-  {},
-) {
-  override get message() {
-    return "Session interrupted by user"
-  }
-}
-
 export class PromptConflictError extends Schema.TaggedError<PromptConflictError>()("Session.PromptConflictError", {
   sessionID: SessionSchema.ID,
   messageID: SessionMessage.ID,

packages/core/src/session/execution.ts

@@ -12,7 +12,6 @@ import { SessionRunner } from "./runner/index.js"
 import { SessionSchema } from "./schema.js"
 import { SessionStore } from "./store.js"
 import { toSessionError } from "./to-session-error.js"
-import { UserInterruptedError } from "./error.js"
 import { SessionInbox } from "./inbox.js"
 
 export interface Interface {
@@ -43,9 +42,7 @@ type InterruptReason = "user" | "shutdown"
 export function terminal(exit: Exit.Exit<void, SessionRunner.RunError>, reason?: InterruptReason) {
   if (Exit.isSuccess(exit)) return { type: "succeeded" as const }
   if (Cause.hasInterrupts(exit.cause)) return { type: "interrupted" as const, reason: reason ?? "shutdown" }
-  const failure = Cause.squash(exit.cause)
-  if (failure instanceof UserInterruptedError) return { type: "interrupted" as const, reason: "user" as const }
-  return { type: "failed" as const, error: toSessionError(failure) }
+  return { type: "failed" as const, error: toSessionError(Cause.squash(exit.cause)) }
 }
 
 /** Process-local execution: drains run in this process using the selected instance. */

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

@@ -11,6 +11,7 @@ import { SessionSchema } from "../schema.js"
 import { SessionStore } from "../store.js"
 import { ShellResult } from "../../shell/result.js"
 import { SubagentCompletion } from "../subagent-completion.js"
+import { SubagentJob } from "../subagent-job.js"
 
 const CONTINUE_AFTER_SERVER_RESTART =
   "The server restarted while you were working. Continue from where you left off without repeating completed work."
@@ -163,28 +164,9 @@ export const layer = (options?: Options) =>
           return
         }
 
-        yield* jobs.start({
+        yield* SubagentJob.start(sessions, jobs, recovery, {
           id: background.id,
-          type: "subagent",
-          title: recovery.description,
           notificationID: background.notificationID,
-          recovery,
-          run: execution.resume(recovery.childSessionID).pipe(
-            Effect.andThen(store.context(recovery.childSessionID)),
-            Effect.map((messages) => {
-              const assistant = messages.findLast(
-                (message) =>
-                  message.type === "assistant" && message.time.completed !== undefined && message.error === undefined,
-              )
-              if (assistant?.type !== "assistant") return "Subagent completed without a text response."
-              return (
-                assistant.content
-                  .filter((part) => part.type === "text")
-                  .map((part) => part.text)
-                  .join("") || "Subagent completed without a text response."
-              )
-            }),
-          ),
         })
         yield* jobs.background(background.id)
         yield* jobs.wait({ id: background.id }).pipe(

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

@@ -4,7 +4,7 @@ import type { AIError } from "@opencode-ai/ai"
 import { Context, Data, Effect } from "effect"
 import { SessionSchema } from "../schema.js"
 import type { Promotable } from "../inbox.js"
-import type { AgentNotFoundError, MessageDecodeError, StepFailedError, UserInterruptedError } from "../error.js"
+import type { AgentNotFoundError, MessageDecodeError, StepFailedError } from "../error.js"
 import { SessionRunnerModel } from "./model.js"
 import type { Instructions } from "../../instructions/index.js"
 
@@ -14,7 +14,6 @@ export type RunError =
   | MessageDecodeError
   | AgentNotFoundError
   | StepFailedError
-  | UserInterruptedError
   | Instructions.InitializationBlocked
 
 export type Continuation = { readonly step: number }

packages/core/src/session/subagent-completion.ts

@@ -3,6 +3,7 @@ export * as SubagentCompletion from "./subagent-completion.js"
 import { Effect } from "effect"
 import type { Job } from "../job.js"
 import type { Session } from "../session.js"
+import { SubagentJob } from "./subagent-job.js"
 
 export const deliver = Effect.fnUntraced(function* (
   sessions: Pick<Session.Interface, "synthetic">,
@@ -16,7 +17,7 @@ export const deliver = Effect.fnUntraced(function* (
   const recovery = input.recovery
   const text =
     input.status === "completed"
-      ? (input.output ?? "Subagent completed without a text response.")
+      ? (input.output ?? SubagentJob.noText)
       : input.status === "error"
         ? (input.error ?? "Subagent failed")
         : "Subagent cancelled"

packages/core/src/session/subagent-job.ts

@@ -0,0 +1,39 @@
+export * as SubagentJob from "./subagent-job.js"
+
+import { Effect } from "effect"
+import type { Job } from "../job.js"
+import type { Session } from "../session.js"
+
+export const noText = "Subagent completed without a text response."
+
+/** The same child execution and result selection for live jobs and restart recovery. */
+export const start = (
+  sessions: Pick<Session.Interface, "resume" | "messages">,
+  jobs: Pick<Job.Interface, "start">,
+  recovery: Extract<Job.Recovery, { kind: "subagent" }>,
+  options?: Pick<Job.StartInput, "id" | "notificationID">,
+) =>
+  jobs.start({
+    id: options?.id ?? recovery.childSessionID,
+    type: "subagent",
+    title: recovery.description,
+    metadata: {},
+    notificationID: options?.notificationID,
+    recovery,
+    run: Effect.gen(function* () {
+      // A failed resume remains a job error, not a successful no-text result.
+      yield* sessions.resume(recovery.childSessionID)
+      const messages = yield* sessions.messages({ sessionID: recovery.childSessionID, order: "desc", limit: 20 })
+      const assistant = messages.find(
+        (message) =>
+          message.type === "assistant" && message.time.completed !== undefined && message.error === undefined,
+      )
+      if (assistant?.type !== "assistant") return noText
+      return (
+        assistant.content
+          .filter((part) => part.type === "text")
+          .map((part) => part.text)
+          .join("") || noText
+      )
+    }),
+  })

packages/core/src/session/to-session-error.ts

@@ -3,7 +3,7 @@ import { Tool } from "@opencode-ai/schema/tool"
 import { SessionError } from "@opencode-ai/schema/session-error"
 import { Permission } from "../permission.js"
 import { Integration } from "../integration.js"
-import { AgentNotFoundError, StepFailedError, UserInterruptedError } from "./error.js"
+import { AgentNotFoundError, StepFailedError } from "./error.js"
 import { SessionRunnerModel } from "./runner/model.js"
 
 export function toSessionError(cause: unknown): SessionError.Error {
@@ -45,7 +45,6 @@ export function toSessionError(cause: unknown): SessionError.Error {
   }
   if (cause instanceof StepFailedError) return cause.error
   if (cause instanceof AgentNotFoundError) return { type: "unknown", message: cause.message }
-  if (cause instanceof UserInterruptedError) return { type: "aborted", message: cause.message }
   if (
     cause instanceof SessionRunnerModel.ModelNotSelectedError ||
     cause instanceof SessionRunnerModel.ModelUnavailableError ||

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

@@ -10,10 +10,10 @@ import { Permission } from "../../permission.js"
 import { Session } from "../../session.js"
 import { SessionSchema } from "../../session/schema.js"
 import { SubagentCompletion } from "../../session/subagent-completion.js"
+import { SubagentJob } from "../../session/subagent-job.js"
 
 export const name = "subagent"
 
-const NO_TEXT = "Subagent completed without a text response."
 const backgroundResult = (sessionID: SessionSchema.ID) => ({
   sessionID,
   status: "running" as const,
@@ -65,22 +65,6 @@ export const Plugin = {
     // continuation job is observable even while a settled generation's observer is finalizing.
     const notifications = new Set<string>()
 
-    // Concatenate the child's final completed assistant text. Distinguishes "completed with no
-    // text" (generic string) from "failed" (the run effect fails, surfaced as a job error).
-    const latestAssistantText = Effect.fn("SubagentTool.latestAssistantText")(function* (sessionID: SessionSchema.ID) {
-      const messages = yield* sessions.messages({ sessionID, order: "desc", limit: 20 })
-      const assistant = messages.find(
-        (message) =>
-          message.type === "assistant" && message.time.completed !== undefined && message.error === undefined,
-      )
-      if (assistant === undefined || assistant.type !== "assistant") return NO_TEXT
-      const text = assistant.content
-        .filter((part): part is Extract<typeof part, { type: "text" }> => part.type === "text")
-        .map((part) => part.text)
-        .join("")
-      return text.length > 0 ? text : NO_TEXT
-    })
-
     const notifyWhenDone = Effect.fn("SubagentTool.notifyWhenDone")(function* (
       recovery: Extract<Job.Recovery, { kind: "subagent" }>,
       startedAt: number,
@@ -225,14 +209,7 @@ export const Plugin = {
                 agent: agent.name,
                 description: input.description,
               }
-              const info = yield* jobs.start({
-                id: child.id,
-                type: name,
-                title: input.description,
-                metadata: {},
-                recovery,
-                run: sessions.resume(child.id).pipe(Effect.andThen(latestAssistantText(child.id))),
-              })
+              const info = yield* SubagentJob.start(sessions, jobs, recovery)
 
               if (background) {
                 yield* jobs.background(info.id)
@@ -258,7 +235,11 @@ export const Plugin = {
                 })
               if (result?.info.status === "cancelled")
                 return yield* new ToolFailure({ message: `Subagent cancelled (sessionID: ${child.id})` })
-              return { sessionID: child.id, status: "completed" as const, output: result?.info.output ?? NO_TEXT }
+              return {
+                sessionID: child.id,
+                status: "completed" as const,
+                output: result?.info.output ?? SubagentJob.noText,
+              }
             }).pipe(
               Effect.map((output) => ({
                 output,

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

@@ -1,5 +1,8 @@
 import { describe, expect, test } from "bun:test"
 import { AIError, TransportError } from "@opencode-ai/ai"
+import { Agent } from "@opencode-ai/schema/agent"
+import { Model } from "@opencode-ai/schema/model"
+import { Provider } from "@opencode-ai/schema/provider"
 import { Database } from "@opencode-ai/core/database/database"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
@@ -15,12 +18,12 @@ import { AbsolutePath } from "@opencode-ai/core/schema"
 import { Session } from "@opencode-ai/core/session"
 import { SessionExecution } from "@opencode-ai/core/session/execution"
 import { SessionRestart } from "@opencode-ai/core/session/execution/restart"
-import { UserInterruptedError } from "@opencode-ai/core/session/error"
 import { SessionEvent } from "@opencode-ai/core/session/event"
 import { SessionInbox } from "@opencode-ai/core/session/inbox"
 import { SessionMessage } from "@opencode-ai/core/session/message"
 import { SessionRunner } from "@opencode-ai/core/session/runner/index"
-import { SessionInboxTable, SessionTable } from "@opencode-ai/core/session/sql"
+import { SessionInboxTable, SessionMessageTable, SessionTable } from "@opencode-ai/core/session/sql"
+import { SubagentJob } from "@opencode-ai/core/session/subagent-job"
 import { SessionStore } from "@opencode-ai/core/session/store"
 import { Cause, Context, Deferred, Effect, Exit, Fiber, Layer, LayerMap, Scope } from "effect"
 import { eq } from "drizzle-orm"
@@ -50,10 +53,6 @@ describe("SessionExecution lifecycle", () => {
     const interrupted = Effect.runSyncExit(Effect.interrupt)
     expect(SessionExecution.terminal(interrupted)).toEqual({ type: "interrupted", reason: "shutdown" })
     expect(SessionExecution.terminal(interrupted, "user")).toEqual({ type: "interrupted", reason: "user" })
-    expect(SessionExecution.terminal(Exit.fail(new UserInterruptedError()))).toEqual({
-      type: "interrupted",
-      reason: "user",
-    })
   })
 
   it.effect("the sweep only lists claimed top-level Sessions", () =>
@@ -378,6 +377,99 @@ describe("SessionExecution lifecycle", () => {
   )
 })
 
+describe("Subagent job results", () => {
+  for (const recovered of [false, true]) {
+    for (const result of ["text", "empty", "stale"] as const) {
+      it.effect(`${recovered ? "recovered" : "live"} jobs use the same ${result} result selection`, () =>
+        Effect.gen(function* () {
+          const database = yield* Database.Service
+          const jobs = yield* Job.Service
+          const store = yield* SessionStore.Service
+          const parent = Session.ID.make("ses_result_parent")
+          const child = Session.ID.make("ses_result_child")
+          yield* seedSessions(database, [parent])
+          yield* seedSessions(database, [child], { parent_id: parent })
+          yield* store.claim(child)
+          const data = {
+            agent: Agent.ID.make("explore"),
+            model: Model.Ref.make({ id: Model.ID.make("test"), providerID: Provider.ID.make("test") }),
+            time: { created: 1, completed: 2 },
+          }
+          yield* database.db
+            .insert(SessionMessageTable)
+            .values([
+              ...[
+                { ...data, content: [{ type: "text" as const, text: "Older answer" }] },
+                {
+                  ...data,
+                  content: [
+                    { type: "reasoning" as const, text: "Not part of the result" },
+                    ...(result === "empty"
+                      ? []
+                      : [
+                          { type: "text" as const, text: "Final " },
+                          { type: "text" as const, text: "answer" },
+                        ]),
+                  ],
+                },
+                {
+                  ...data,
+                  content: [{ type: "text" as const, text: "Failed answer" }],
+                  error: { type: "unknown", message: "Failed" },
+                },
+                { ...data, time: { created: 1 }, content: [{ type: "text" as const, text: "Unfinished answer" }] },
+              ].map((data, seq) => ({
+                id: SessionMessage.ID.create(),
+                session_id: child,
+                type: "assistant" as const,
+                seq: seq + 1,
+                data,
+              })),
+              ...Array.from({ length: result === "stale" ? 20 : 0 }, (_, seq) => ({
+                id: SessionMessage.ID.create(),
+                session_id: child,
+                type: "synthetic" as const,
+                seq: seq + 5,
+                data: { text: "Later activity", time: { created: 3 } },
+              })),
+            ])
+            .run()
+            .pipe(Effect.orDie)
+
+          const recovery = {
+            kind: "subagent" as const,
+            parentSessionID: parent,
+            childSessionID: child,
+            agent: "explore",
+            description: "Select the child result",
+          }
+          const scope = yield* Scope.make()
+          yield* Effect.addFinalizer(() => Scope.close(scope, Exit.void))
+          const restarted = yield* Job.make.pipe(Effect.provideService(Scope.Scope, scope))
+          const context = yield* buildExecution(scope, () => Effect.void, undefined, restarted)
+          const sessions = Context.get(context, Session.Service)
+          const id = recovered ? "recovered-child-job" : child
+          if (recovered) {
+            yield* jobs.start({ id, type: "subagent", recovery, run: Effect.never })
+            const marker = yield* jobs.background(id)
+            yield* Context.get(context, SessionRestart.Service).resumeSuspendedSessions
+            expect((yield* restarted.get(id))?.notificationID).toBe(marker?.notificationID)
+          }
+          if (!recovered) yield* SubagentJob.start(sessions, restarted, recovery)
+
+          expect((yield* restarted.wait({ id })).info).toMatchObject({
+            id,
+            type: "subagent",
+            title: recovery.description,
+            status: "completed",
+            output: result === "text" ? "Final answer" : "Subagent completed without a text response.",
+          })
+        }),
+      )
+    }
+  }
+})
+
 describe("SessionRestart background recovery", () => {
   it.effect("wakes idle shell owners and delivers recovered notices exactly once", () =>
     Effect.gen(function* () {
@@ -1342,6 +1434,7 @@ function buildExecution(
         const execution = yield* SessionExecution.Service
         return Session.Service.of({
           ...sessions,
+          resume: execution.resume,
           synthetic: (input) =>
             sessions
               .synthetic({ ...input, resume: false })