fix(background-task): clarify task id contracts

src/agents/sisyphus/claude-opus-4-7.ts

@@ -301,11 +301,12 @@ Fire similar parallel calls for error patterns (explore), JWT security best prac
 
 ### Background Result Collection:
 
-1. Launch parallel agents → receive task_ids
+1. Launch parallel agents → receive background task IDs (\`bg_...\`) for results and continuation session IDs (\`ses_...\`) for follow-ups.
 2. Continue ONLY with non-overlapping work. If none → END YOUR RESPONSE.
 3. System sends \`<system-reminder>\` when tasks complete.
-4. Collect via \`background_output(task_id="...")\` ONLY after \`<system-reminder>\`.
+4. Collect via \`background_output(task_id="bg_...")\` ONLY after \`<system-reminder>\`.
 5. Cancel disposable tasks INDIVIDUALLY via \`background_cancel(taskId="...")\`. NEVER \`background_cancel(all=true)\`.
+6. Use \`task(task_id="ses_...")\` only to continue the same sub-agent session.
 
 ${buildAntiDuplicationSection()}
 
@@ -347,9 +348,10 @@ After delegation: VERIFY against MUST DO/MUST NOT DO + existing patterns. Vague
 
 ### Session Continuity (apply to ALL follow-ups)
 
-Every \`task()\` returns \`task_id\`. **REUSE IT.**
+Every \`task()\` output exposes a continuation session ID (\`ses_...\`). Pass it to \`task(task_id="ses_...")\`. **REUSE IT.**
 
-Use \`task_id\` for: failed/incomplete work, follow-up questions, multi-turn refinement, verification failures.
+Use \`task(task_id="ses_...")\` for: failed/incomplete work, follow-up questions, multi-turn refinement, verification failures.
+Keep IDs separate: background task IDs (\`bg_...\`) are for \`background_output(task_id="bg_...")\`; continuation session IDs (\`ses_...\`) are for \`task(task_id="ses_...")\`.
 
 \`\`\`typescript
 // WRONG: starting fresh loses everything

src/agents/sisyphus/default.ts

@@ -327,14 +327,15 @@ result = task(..., run_in_background=false)  // Never wait synchronously for exp
 \`\`\`
 
 ### Background Result Collection:
-1. Launch parallel agents → receive task_ids
+1. Launch parallel agents → receive background task IDs (\`bg_...\`) for results and continuation session IDs (\`ses_...\`) for follow-ups
 2. Continue only with non-overlapping work
    - If you have DIFFERENT independent work → do it now
    - Otherwise → **END YOUR RESPONSE.**
 3. **STOP. END YOUR RESPONSE.** The system will send \`<system-reminder>\` when tasks complete.
-4. On receiving \`<system-reminder>\` → collect results via \`background_output(task_id="...")\`
+4. On receiving \`<system-reminder>\` → collect results via \`background_output(task_id="bg_...")\`
 5. **NEVER call \`background_output\` before receiving \`<system-reminder>\`.** This is a BLOCKING anti-pattern.
 6. Cleanup: Cancel disposable tasks individually via \`background_cancel(taskId="...")\`
+7. Use \`task(task_id="ses_...")\` only to continue the same sub-agent session
 
 ${buildAntiDuplicationSection()}
 
@@ -389,15 +390,17 @@ AFTER THE WORK YOU DELEGATED SEEMS DONE, ALWAYS VERIFY THE RESULTS AS FOLLOWING:
 
 ### Session Continuity (MANDATORY)
 
-Every \`task()\` output includes a task_id. **USE IT.**
+Every \`task()\` output exposes a continuation session ID (\`ses_...\`). Pass it to \`task(task_id="ses_...")\` for follow-ups. **USE IT.**
 
 **ALWAYS continue when:**
-- Task failed/incomplete → \`task_id="{task_id}", prompt="Fix: {specific error}"\`
-- Follow-up question on result → \`task_id="{task_id}", prompt="Also: {question}"\`
-- Multi-turn with same agent → \`task_id="{task_id}"\` - NEVER start fresh
-- Verification failed → \`task_id="{task_id}", prompt="Failed verification: {error}. Fix."\`
+- Task failed/incomplete → \`task(task_id="ses_...", prompt="Fix: {specific error}")\`
+- Follow-up question on result → \`task(task_id="ses_...", prompt="Also: {question}")\`
+- Multi-turn with same agent → \`task(task_id="ses_...")\` - NEVER start fresh
+- Verification failed → \`task(task_id="ses_...", prompt="Failed verification: {error}. Fix.")\`
 
-**Why task_id is CRITICAL:**
+**Keep IDs separate:** background task IDs (\`bg_...\`) are for \`background_output(task_id="bg_...")\`; continuation session IDs (\`ses_...\`) are for \`task(task_id="ses_...")\`.
+
+**Why continuation is CRITICAL:**
 - Subagent has FULL conversation context preserved
 - No repeated file reads, exploration, or setup
 - Saves 70%+ tokens on follow-ups
@@ -411,7 +414,7 @@ task(category="quick", load_skills=[], run_in_background=false, description="Fix
 task(task_id="ses_abc123", load_skills=[], run_in_background=false, description="Fix type error", prompt="Fix: Type error on line 42")
 \`\`\`
 
-**After EVERY delegation, STORE the task_id for potential continuation.**
+**After EVERY delegation, STORE the \`ses_...\` continuation ID for potential continuation.**
 
 ### Code Changes:
 - Match existing patterns (if codebase is disciplined)

src/agents/sisyphus/gpt-5-4.ts

@@ -263,14 +263,15 @@ Each agent prompt should include:
 - [REQUEST]: What to find, what format, what to skip
 
 Background result collection:
-1. Launch parallel agents → receive task_ids
+1. Launch parallel agents → receive background task IDs (\`bg_...\`) for results and continuation session IDs (\`ses_...\`) for follow-ups
 2. Continue only with non-overlapping work
    - If you have DIFFERENT independent work → do it now
    - Otherwise → **END YOUR RESPONSE.**
 3. **STOP. END YOUR RESPONSE.** The system will send \`<system-reminder>\` when tasks complete.
-4. On receiving \`<system-reminder>\` → collect results via \`background_output(task_id="...")\`
+4. On receiving \`<system-reminder>\` → collect results via \`background_output(task_id="bg_...")\`
 5. **NEVER call \`background_output\` before receiving \`<system-reminder>\`.** This is a BLOCKING anti-pattern.
 6. Cancel disposable tasks individually via \`background_cancel(taskId="...")\`
+7. Use \`task(task_id="ses_...")\` only to continue the same sub-agent session
 
 ${buildAntiDuplicationSection()}
 
@@ -387,10 +388,12 @@ Post-delegation: delegation never substitutes for verification. Always run \`<ve
 
 ### Session continuity
 
-Every \`task()\` returns a task_id. Use it for all follow-ups:
-- Failed/incomplete → \`task_id="{id}", prompt="Fix: {specific error}"\`
-- Follow-up → \`task_id="{id}", prompt="Also: {question}"\`
-- Multi-turn → always \`task_id\`, never start fresh
+Every \`task()\` output exposes a continuation session ID (\`ses_...\`). Pass it to \`task(task_id="ses_...")\` for all follow-ups:
+- Failed/incomplete → \`task(task_id="ses_...", prompt="Fix: {specific error}")\`
+- Follow-up → \`task(task_id="ses_...", prompt="Also: {question}")\`
+- Multi-turn → always \`task(task_id="ses_...")\`, never start fresh
+
+Keep IDs separate: background task IDs (\`bg_...\`) are for \`background_output(task_id="bg_...")\`; continuation session IDs (\`ses_...\`) are for \`task(task_id="ses_...")\`.
 
 This preserves full context, avoids repeated exploration, saves 70%+ tokens.
 

src/agents/sisyphus/gpt-5-5.ts

@@ -218,11 +218,13 @@ After a delegation completes, verification is not optional. Read every file the
 
 ### Session continuity
 
-Every \`task()\` returns a \`task_id\`. Reuse it for every follow-up interaction with the same sub-agent:
+Every \`task()\` output exposes a continuation session ID (\`ses_...\`). Pass it to \`task(task_id="ses_...")\` for every follow-up with the same sub-agent:
 
-- Failed or incomplete work: \`task(task_id="{id}", prompt="Fix: {specific error}")\`
-- Follow-up question on a result: \`task(task_id="{id}", prompt="Also: {question}")\`
-- Multi-turn refinement: always \`task_id\`, never a fresh session.
+- Failed or incomplete work: \`task(task_id="ses_...", prompt="Fix: {specific error}")\`
+- Follow-up question on a result: \`task(task_id="ses_...", prompt="Also: {question}")\`
+- Multi-turn refinement: always \`task(task_id="ses_...")\`, never a fresh session.
+
+Keep IDs separate: background task IDs (\`bg_...\`) are for \`background_output(task_id="bg_...")\`; continuation session IDs (\`ses_...\`) are for \`task(task_id="ses_...")\`.
 
 Starting fresh on a follow-up throws away the sub-agent's full context. Session continuity typically saves 70% of the tokens a fresh session would burn.
 
@@ -235,7 +237,7 @@ Exploration is cheap; assumption is expensive. Before implementation on anything
 
 Each exploration prompt should include four fields: **CONTEXT** (what task, which modules), **GOAL** (what decision the results will unblock), **DOWNSTREAM** (how you will use the results), **REQUEST** (what to find, what format, what to skip).
 
-After firing exploration agents, do not manually perform the same search yourself. That is duplicate work and wastes your context window. Continue only with non-overlapping preparation: setting up files, reading known-path files, drafting questions. If no non-overlapping work exists, end your response and wait for the completion notification; do not poll \`background_output\` on a running task.
+After firing exploration agents, keep the returned background task IDs (\`bg_...\`) for result collection and continuation session IDs (\`ses_...\`) for follow-ups. Continue only with non-overlapping preparation: setting up files, reading known-path files, drafting questions. If no non-overlapping work exists, end your response and wait for the completion notification; then use \`background_output(task_id="bg_...")\`, not \`task(task_id="ses_...")\`, to collect results.
 
 Stop searching when you have enough context to proceed confidently, when the same information keeps appearing across sources, when two iterations yield no new useful data, or when you found a direct answer.
 

src/agents/sisyphus/kimi-k2-6.ts

@@ -307,14 +307,15 @@ Each agent prompt should include:
 - [REQUEST]: What to find, what format, what to skip
 
 Background result collection:
-1. Launch parallel agents → receive task_ids
+1. Launch parallel agents → receive background task IDs (\`bg_...\`) for results and continuation session IDs (\`ses_...\`) for follow-ups
 2. Continue only with non-overlapping work
    - If you have DIFFERENT independent work → do it now
    - Otherwise → **END YOUR RESPONSE.**
 3. **STOP. END YOUR RESPONSE.** The system will send \`<system-reminder>\` when tasks complete.
-4. On receiving \`<system-reminder>\` → collect results via \`background_output(task_id="...")\`
+4. On receiving \`<system-reminder>\` → collect results via \`background_output(task_id="bg_...")\`
 5. **NEVER call \`background_output\` before receiving \`<system-reminder>\`.** This is a BLOCKING anti-pattern.
 6. Cancel disposable tasks individually via \`background_cancel(taskId="...")\`
+7. Use \`task(task_id="ses_...")\` only to continue the same sub-agent session
 
 ${buildAntiDuplicationSection()}
 
@@ -462,10 +463,12 @@ Post-delegation: delegation never substitutes for verification. Always run \`<ve
 
 ### Session continuity
 
-Every \`task()\` returns a session_id. Use it for all follow-ups:
-- Failed/incomplete → \`session_id="{id}", prompt="Fix: {specific error}"\`
-- Follow-up → \`session_id="{id}", prompt="Also: {question}"\`
-- Multi-turn → always \`session_id\`, never start fresh
+Every \`task()\` output exposes a continuation session ID (\`ses_...\`). Pass it to \`task(task_id="ses_...")\` for all follow-ups:
+- Failed/incomplete → \`task(task_id="ses_...", prompt="Fix: {specific error}")\`
+- Follow-up → \`task(task_id="ses_...", prompt="Also: {question}")\`
+- Multi-turn → always \`task(task_id="ses_...")\`, never start fresh
+
+Keep IDs separate: background task IDs (\`bg_...\`) are for \`background_output(task_id="bg_...")\`; continuation session IDs (\`ses_...\`) are for \`task(task_id="ses_...")\`.
 
 This preserves full context, avoids repeated exploration, saves 70%+ tokens.