fix(chatd): improve compaction prompt to preserve forward momentum#22989
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The previous summarization prompt told the model to "omit next-step
suggestions," and the summary prefix framed compacted context as
passive history ("Summary of earlier chat context"). This caused the
model to lose direction mid-task after compaction — it would read a
factual recap with no forward momentum and stop or ask the user what
to do next.
The new prompt:
- Removes the "omit next-step suggestions" instruction
- Explicitly asks for in-progress and remaining work
- Captures the specific action being performed when compaction fired
- Frames the summary prefix as an active handoff with a "Continue"
directive
This aligns with patterns used by Codex, Mux, Continue, and Copilot
Chat, all of which preserve forward intent through compaction.
mattvollmer
approved these changes
Mar 12, 2026
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Problem
The summarization prompt explicitly tells the model to "Omit pleasantries and next-step suggestions" and the summary prefix frames the compacted context as passive history:
Summary of earlier chat context:. After compaction mid-task, the model reads a factual recap with no forward momentum, loses its direction, and either stops or asks the user what to do.Research
I compared our compaction prompt against several other agents:
Every other major agent explicitly preserves forward intent and in-progress state. Coder was the only one telling the model to omit next steps.
Changes
Summary prompt:
Omit next-step suggestionsInclude:list with explicit items for in-progress work, remaining work, and the specific action being performed when compaction firedcontext compaction(matching Codex's framing)Summary prefix:
Summary of earlier chat context:The following is a summary of the earlier conversation. The assistant was actively working when the context was compacted. Continue the work described below:The prefix is the first thing the model reads post-compaction — framing it as an active handoff with an explicit "Continue" directive primes the model to resume work rather than wait.