fix(delegate-task): clarify sync inactivity timeout

src/tools/delegate-task/sync-poll-timeout.test.ts

@@ -75,7 +75,7 @@ describe("syncPollTimeoutMs threading", () => {
             taskId: undefined,
           }, 120_000)
 
-          expect(result).toBe("Poll timeout reached after 120000ms for session ses_custom")
+          expect(result).toBe("Poll inactivity timeout reached after 120000ms without active OpenCode status for session ses_custom")
           expect(abortCount).toBe(1)
         })
       })
@@ -141,7 +141,7 @@ describe("syncPollTimeoutMs threading", () => {
             taskId: undefined,
           })
 
-          expect(result).toBe(`Poll timeout reached after ${MAX_POLL_TIME_MS}ms for session ses_default`)
+          expect(result).toBe(`Poll inactivity timeout reached after ${MAX_POLL_TIME_MS}ms without active OpenCode status for session ses_default`)
         })
       })
 
@@ -159,7 +159,7 @@ describe("syncPollTimeoutMs threading", () => {
             taskId: undefined,
           })
 
-          expect(result).toBe("Poll timeout reached after 120000ms for session ses_legacy")
+          expect(result).toBe("Poll inactivity timeout reached after 120000ms without active OpenCode status for session ses_legacy")
         })
       })
     })
@@ -177,7 +177,7 @@ describe("syncPollTimeoutMs threading", () => {
             taskId: undefined,
           }, 10)
 
-          expect(result).toBe("Poll timeout reached after 50ms for session ses_guard")
+          expect(result).toBe("Poll inactivity timeout reached after 50ms without active OpenCode status for session ses_guard")
         })
       })
     })

src/tools/delegate-task/sync-session-poller.test.ts

@@ -100,7 +100,7 @@ describe("pollSyncSession", () => {
       }, 50)
 
       // then: times out (ignores stale error)
-      expect(result).toContain("Poll timeout reached")
+      expect(result).toContain("Poll inactivity timeout reached")
     })
 
     test("detects completion when assistant message has terminal finish reason", async () => {
@@ -459,7 +459,7 @@ describe("pollSyncSession", () => {
       }, 0)
 
       // then: returns timeout error
-      expect(result).toBe("Poll timeout reached after 50ms for session ses_timeout")
+      expect(result).toBe("Poll inactivity timeout reached after 50ms without active OpenCode status for session ses_timeout")
       expect(abortCount).toBe(1)
     })
   })

src/tools/delegate-task/sync-session-poller.ts

@@ -214,9 +214,11 @@ export async function pollSyncSession(
   }
 
   if (timedOut) {
-    log("[task] Poll timeout reached", { sessionID: input.sessionID, pollCount })
+    log("[task] Poll inactivity timeout reached", { sessionID: input.sessionID, pollCount })
     abortSyncSession(client, input.sessionID, "poll_timeout")
   }
 
-  return timedOut ? `Poll timeout reached after ${maxPollTimeMs}ms for session ${input.sessionID}` : null
+  return timedOut
+    ? `Poll inactivity timeout reached after ${maxPollTimeMs}ms without active OpenCode status for session ${input.sessionID}`
+    : null
 }

src/tools/delegate-task/timing.test.ts

@@ -3,7 +3,7 @@ const { describe, expect, test } = require("bun:test")
 import { __resetTimingConfig, __setTimingConfig, getDefaultSyncPollTimeoutMs, getTimingConfig } from "./timing"
 
 describe("timing sync poll timeout defaults", () => {
-  test("default sync timeout is 30 minutes", () => {
+  test("default sync inactivity timeout is 30 minutes", () => {
     // #given
     __resetTimingConfig()
 
@@ -14,7 +14,7 @@ describe("timing sync poll timeout defaults", () => {
     expect(timeout).toBe(30 * 60 * 1000)
   })
 
-  test("default sync timeout accessor follows MAX_POLL_TIME_MS config", () => {
+  test("default sync inactivity timeout accessor follows MAX_POLL_TIME_MS config", () => {
     // #given
     __resetTimingConfig()
 

src/tools/delegate-task/tool-description.test.ts

@@ -0,0 +1,18 @@
+import { describe, expect, test } from "bun:test"
+
+import { createDelegateTaskPresentation } from "./tool-description"
+
+describe("createDelegateTaskPresentation", () => {
+  test("#given sync task usage #when description is rendered #then timeout is described as inactivity based", () => {
+    //#given
+    const presentation = createDelegateTaskPresentation({})
+
+    //#when
+    const description = presentation.description
+
+    //#then
+    expect(description).toContain("30-minute inactivity window")
+    expect(description).toContain("busy/retry/running")
+    expect(description).toContain("not a total wall-clock limit")
+  })
+})

src/tools/delegate-task/tool-description.ts

@@ -67,6 +67,7 @@ export function createDelegateTaskPresentation(options: DelegateTaskToolOptions)
   ${categoryList}
   - subagent_type: Use specific agent directly (explore, librarian, oracle, metis, momus)
   - run_in_background: REQUIRED. true=async (returns task_id), false=sync (waits). Use background=true ONLY for parallel exploration with 5+ independent queries.
+    Sync waits use a 30-minute inactivity window: OpenCode busy/retry/running status resets the window, so this is not a total wall-clock limit.
   - task_id: Existing task to continue (from previous task output). Continues the same subagent session with FULL CONTEXT PRESERVED.
   - command: The command that triggered this task (optional, for slash command tracking).