🤖 fix: keep process alive when stdin closes in agentSessionCli #529
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Terminal-bench was failing with all tasks showing 0 input/output tokens because Bun was exiting immediately after stdin closed, even though async work (API calls) was still pending. The agentSessionCli reads the user message from stdin, then waits for stream completion. However, once stdin reaches EOF and is consumed, Bun may exit if it detects no other active handles keeping the event loop alive. Add an explicit keepalive interval that ensures the process stays alive until main() completes. This interval runs far into the future but gets cleared in the finally block once the agent session finishes. This fixes the nightly terminal-bench failures where all 80 tasks were failing with agent_timeout and 0 tokens.
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## Problem Terminal-bench was failing with all tasks showing 0 input/output tokens because the agent was exiting immediately after receiving the user message, without making any API calls. **Symptoms:** - Latest nightly runs (Nov 5-7): All 80 tasks failed with `agent_timeout` - Agent ran for only ~45 seconds then exited - `total_input_tokens: 0`, `total_output_tokens: 0` - Stream started with `caught-up` and `user` message, but no `stream-delta` or `stream-end` events **Root cause:** The `agentSessionCli.ts` reads the user message from stdin via a pipe: ```bash printf '%s' "$instruction" | bun src/debug/agentSessionCli.ts ... ``` Once stdin reaches EOF and is consumed, Bun detects no other active handles keeping the event loop alive and exits the process, **even though async work (API streaming) is still pending**. ## Solution Add an explicit keepalive interval that ensures the process stays alive until `main()` completes. The interval runs far into the future (1000 seconds) but gets cleared in the finally block once the agent session finishes. ## Testing **Before fix:** - Run #19173435224: 1 task, 0 tokens, ~2 min total (agent ran 45s) - Agent exited immediately after user message **After fix:** - Run #19173548174: 1 task, **resolved: true**, ~7 min total (agent ran 3m17s) - 22 tool calls made - Stream-delta events present - Agent completed successfully ## Related - Fixes nightly terminal-bench failures from Nov 5-7 - Related to PR #507 (dist/ in archive) and PR #513 (build step in workflow) _Generated with `cmux`_
ibetitsmike
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Nov 7, 2025
## Problem Terminal-bench was failing with all tasks showing 0 input/output tokens because the agent was exiting immediately after receiving the user message, without making any API calls. **Symptoms:** - Latest nightly runs (Nov 5-7): All 80 tasks failed with `agent_timeout` - Agent ran for only ~45 seconds then exited - `total_input_tokens: 0`, `total_output_tokens: 0` - Stream started with `caught-up` and `user` message, but no `stream-delta` or `stream-end` events **Root cause:** The `agentSessionCli.ts` reads the user message from stdin via a pipe: ```bash printf '%s' "$instruction" | bun src/debug/agentSessionCli.ts ... ``` Once stdin reaches EOF and is consumed, Bun detects no other active handles keeping the event loop alive and exits the process, **even though async work (API streaming) is still pending**. ## Solution Add an explicit keepalive interval that ensures the process stays alive until `main()` completes. The interval runs far into the future (1000 seconds) but gets cleared in the finally block once the agent session finishes. ## Testing **Before fix:** - Run #19173435224: 1 task, 0 tokens, ~2 min total (agent ran 45s) - Agent exited immediately after user message **After fix:** - Run #19173548174: 1 task, **resolved: true**, ~7 min total (agent ran 3m17s) - 22 tool calls made - Stream-delta events present - Agent completed successfully ## Related - Fixes nightly terminal-bench failures from Nov 5-7 - Related to PR #507 (dist/ in archive) and PR #513 (build step in workflow) _Generated with `cmux`_
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Problem
Terminal-bench was failing with all tasks showing 0 input/output tokens because the agent was exiting immediately after receiving the user message, without making any API calls.
Symptoms:
agent_timeouttotal_input_tokens: 0,total_output_tokens: 0caught-upandusermessage, but nostream-deltaorstream-endeventsRoot cause:
The
agentSessionCli.tsreads the user message from stdin via a pipe:Once stdin reaches EOF and is consumed, Bun detects no other active handles keeping the event loop alive and exits the process, even though async work (API streaming) is still pending.
Solution
Add an explicit keepalive interval that ensures the process stays alive until
main()completes. The interval runs far into the future (1000 seconds) but gets cleared in the finally block once the agent session finishes.Testing
Before fix:
After fix:
Related
Generated with
cmux