NousResearch/hermes-agent

Fix thinking-prefill marker causing Gemini 400 errors

Cluster 75121. Data as of 2026-10-29 11:48 UTC

Nothing open on GitHub. Fix merged in #82930 on 10 Aug 2026. Check it covers your case.

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Known?: Yes. 3 related items grouped here, 1 issue already closed.
Fix event: A fix was merged to main in PR #82930. Check it covers your case. No release data is tracked.
Tracker: The maintainers' tracker marks this resolved, deciding PR #82930. That is separate from the fix event.
Still open: Nothing open on GitHub.

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A bug where thinking-only prefill sends a trailing model turn to Gemini, triggering 400 errors because reasoning stripping runs before the thinking-only drop pass. The fixes preserve the thinking-prefill marker so the drop pass can correctly strip trailing stubs.

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Fixes on record

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

#82930 fix(agent): keep thinking-prefill marker so drop pass can strip trailing stubs

merged to main

files: agent/chat_completion_helpers.py, agent/conversation_loop.py, run_agent.py, tests/run_agent/test_thinking_only_sanitizer.py, tests/run_agent/test_thinking_prefill_trailing_turn.py

1 PR closed without merging

From the close comments: merged via another change 1

#75142 fix(agent): keep the thinking-prefill marker so the drop pass can strip trailing stubs · merged via another change → #82930

Closed issues · 1

Closed#75121[Bug]: Thinking-only prefill sends a trailing model turn to Gemini and 400s the turn, because reasoning stripping runs before the thinking-only drop pass

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At a glance

Merged PRs: #82930
Closed issues: 1
Attempts: 1 PR closed without merging
Fix link checked: 10 Aug 2026

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