fix(compaction): mark end of context summary in role=user fallback (salvage #17121) - #20169
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alt-glitch
added
type/bug
When the head ends with assistant/tool and the tail starts with assistant, the summary is inserted as a standalone role="user" message. The body's verbatim "## Active Task" quote then gets read as fresh user input by weak/local models (#11475, #14521). The merge-into-tail path already appends an explicit end-of-summary marker for this reason. Mirror it on the standalone path so both insertion routes give the model the same "summary above, not new input" signal.
This was referenced May 16, 2026
This was referenced Jun 9, 2026
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Salvages @wmagev's PR #17121 onto current main (trivial test-file conflict with newer sanitizer test resolved — both tests now land).
What it does
When compaction's standalone-summary path picks role="user" (head ends with assistant/tool), the body's verbatim
## Active Taskquote gets read as fresh user input by weak/local models (#11475, #14521). The merge-into-tail path already appends an--- END OF CONTEXT SUMMARY ---marker; this mirrors it on the standalone path so both routes give the same signal.Changes
agent/context_compressor.py— append end-of-summary marker whensummary_role == 'user'and we're not merging into tail.tests/agent/test_context_compressor.py— newtest_user_role_summary_carries_end_marker.scripts/release.py— AUTHOR_MAP entry for wmagev.Validation
tests/agent/test_context_compressor.py— 68 passed locally.Closes #17121 via salvage.