NousResearch/hermes-agent

Fix stdout buffering in headless/piped mode

Cluster 92281. Data as of 2026-10-25 11:21 UTC

Nothing open on GitHub. Fix merged in #121601 on 24 Sep 2026. Check it covers your case.

open issues

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items grouped

Known?: Yes. 4 related items grouped here, 1 issue already closed.
Fix event: A fix was merged to main in PR #121601. Check it covers your case. No release data is tracked.
Tracker: The maintainers' tracker marks this resolved, deciding PR #121601. That is separate from the fix event.
Still open: Nothing open on GitHub.

Next step: read #121601, then check it covers your case.

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These members address an issue where stdout is block-buffered instead of line-buffered when running without a TTY, causing output to appear stalled. A fix applies line-buffering to piped stdout so output streams in real time during headless operation.

Open issues0

No open issues.

Open PRs0

No open pull requests.

Fixes on record

Merged to main. A stamp counts the issues a fix is linked to.

#121601 fix(cli): stream answers after reasoning, no double-render of interrupted streamed replies, line-buffer headless stdout

merged to main

files: hermes_cli/cli_chat_turn_mixin.py, hermes_cli/cli_init_mixin.py, hermes_cli/cli_stream_mixin.py, hermes_logging.py, tests/hermes_cli/test_status_lines_held_during_stream_box.py, tests/hermes_cli/test_stream_delta_think_tag.py, tests/test_hermes_logging.py

2 PRs closed without merging

From the close comments: done elsewhere 1 · merged via another change 1

#92288 fix(logging): line-buffer a piped stdout so headless log streams track the agent loop · merged via another change → ed805bf, #121601, #92281
#92451 fix(cli): line-buffer stdout when headless so piped output streams live · done elsewhere → ed805bf, #92281, #121601

Closed issues · 1

Closed#92281[Bug]: stdout is block-buffered when hermes runs headless (piped, no TTY), making live agent work look like a stall

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At a glance

Merged PRs: #121601
Closed issues: 1
Attempts: 2 PRs closed without merging
Fix link checked: 24 Sep 2026

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