Model in BUILD mode does not have enough context to continue after compaction #3031

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1. github-actions commented on Oct 8, 2025

   

   github-actionsBot

   on Oct 8, 2025 – with GitHub Actions

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   This issue might be a duplicate of existing issues. Please check:

   • Session automatically compacted, destroying the entire working context #2945: Session automatically compacted, destroying the entire working context - describes same issue where compaction destroys working context in build mode
   • compact causes llm to forget convo #2234: compact causes llm to forget convo - model forgets conversation context after compaction, leading to starting fresh
   • Preload instructions after /compact #940: Preload instructions after /compact - requests automatic preloading of instructions after compaction to maintain context
   • [Feature Request] Add User Controls for Context Management #1990: Add User Controls for Context Management - broader feature request for context management that could address compaction issues

   Feel free to ignore if none of these address your specific case.
2. rekram1-node commented on Oct 8, 2025

   

   rekram1-node

   on Oct 8, 2025

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   P.S. I have a suspicion that AGENTS.md is not included in the context after compaction (it should), but I did not verify it rigourously.

   It is included
3. rekram1-node commented on Oct 8, 2025

   

   rekram1-node

   on Oct 8, 2025

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   Compaction summaries are too basic, and do not include context sufficient information for the model to continue work when compaction happens in BUILD mode, leading to nonsensical changes and wasted work.

   yeah the prompt could use some work
4. rekram1-node

   assigned

   thdxr

   on Oct 8, 2025
5. tuxillo commented on Dec 21, 2025

   

   tuxillo

   on Dec 21, 2025

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   P.S. I have a suspicion that AGENTS.md is not included in the context after compaction (it should), but I did not verify it rigourously.

   It is included

   there must be some use cases where it is not because i find myself reminding it over and over that there is an AGENTS.md in the root of the project 😄
6. maxeonyx commented on Jan 12, 2026

   

   maxeonyx

   on Jan 12, 2026

   Last edited by maxeonyx

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   @agladysh I have a PR which will support custom prompts for compaction. I have been having great success with the following custom prompt (although, I have mostly used it with Opus 4.5, so bears testing for other models.)

   ---
   description: Compact & hand over
   compact: true
   ---
   
   Curate a hand-over note from this conversation, so that a new agent can take over and continue aiding the user.
   
   The new agent will have no context except what you provide in the note - so focus on informing them of everything they will need (while leaving out anything they won't need).
   
   Pay attention to the vibe, the exact workflow. Record some interactions or habits that went well - put the abridged examples in the note. Show by example!
   
   Make sure that the note contains all of:
   
   - The goal of this work, keeping specific wording by the user as much as possible.
   - The history of the conversation & work, especially open threads or things that may be useful going forward.
   - Specific commands that will be useful, specific filenames that will be useful, other specific details.
   - Briefly, any issues that were encountered and the solution, to save the new agent doing any debugging again.
   
   If the last message was one from the user, please include it exactly, at the very end of the note.
   
   Focus on including details that would not be recoverable, or that would take time to do so, but feel free to leave out anything that the new agent would easily discover themselves, and encourage them to do so.
   
   Take the time and space to do a good job of representing the work & demonstrating to the new agent how to seamlessly continue it.
   
7. leohenon commented on Feb 17, 2026

   

   leohenon

   on Feb 17, 2026

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   Another potential improvement: include the last user prompt in the compaction replay message. Right now the model only sees the summary after compaction but loses the original request. Including it would give better continuity, especially during auto-compaction mid-task.

   👍React with 👍2Reacted by Mahmoud Mabrouk and Alfie John
8. github-actions commented on Apr 19, 2026

   

   github-actionsBot

   on Apr 19, 2026 – with GitHub Actions

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   To stay organized issues are automatically closed after 60 days of no activity. If the issue is still relevant please open a new one.
9. github-actions

   closed this as completedon Apr 19, 2026