[BUG] Frequent premature compaction + infinite loop + prompt freezing with Opus 4.6 on 1M context
Preflight Checklist
- [x] I have searched existing issues and this hasn't been reported yet
- [x] This is a single bug report (please file separate reports for different bugs)
- [x] I am using the latest version of Claude Code
What's Wrong?
Claude Code Version: 2.1.89
Model: claude-opus-4-6 (1M context)
OS: Debian 6.1.164-1
Platform: CLI
Bug Description:
Conversation is being compacted every 5–10 minutes despite context window never exceeding ~100K tokens. This has been ongoing for 1+ hour. The session is also unusually slow, and the prompt randomly freezes requiring Esc to unblock.
Expected Behavior:
Compaction should only trigger when approaching the context limit, not at <10% usage.
Actual Behavior:
- Compaction triggers every 5–10 minutes at low token usage (~100K / 1M)
- Session is significantly slower than normal
- Prompt occasionally freezes and requires Esc + Enter to recover
- Behavior consistent with the infinite compaction loop reported in #6004, #4878
Steps to Reproduce:
- Start Claude Code with
claude-opus-4-6on 1M context - Begin a multi-file coding session
- Observe repeated compaction at low token usage within minutes
What Should Happen?
Conversation compaction should only trigger when the context window is close to its limit (e.g., 90–95% of the 1M token budget). With a 1M context window and only ~100K tokens used, compaction should not occur at all. The session should remain responsive, and the prompt should never freeze or require manual interruption (Esc) to recover.
Error Messages/Logs
Steps to Reproduce
Steps to Reproduce:
- Start Claude Code with
claude-opus-4-6on 1M context - Begin a multi-file coding session
- Observe repeated compaction at low token usage within minutes
Claude Model
Opus
Is this a regression?
Yes, this worked in a previous version
Last Working Version
_No response_
Claude Code Version
2.1.89
Platform
Anthropic API
Operating System
Ubuntu/Debian Linux
Terminal/Shell
Windows Terminal
Additional Information
_No response_
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7 Comments
behavior worsened between 2.1.92 and 2.1.96.
only 4 prompts and again contextwindow is full and compact necessary.
Seems some background tasks in claude code self are blowing it up
compact starts here at around 190k, far less then modell opus(1M) can handle
The premature compaction on 1M context is likely a threshold miscalculation — Claude Code's default assumes 200K. Cozempic auto-detects 1M context windows and adjusts thresholds accordingly (also configurable via
--context-windoworCOZEMPIC_CONTEXT_WINDOW). Its guard daemon prunes session bloat proactively so compaction triggers far less frequently.pip install cozempic && cozempic guard— repo at https://github.com/Ruya-AI/cozempic. Curious if this fixes the frequency for you.I get repeated "Auto compact is thrashing errors" in Cowork. my last one was prompted by just typing /setup-cowork.
this is nuking my credits. I think there might be a skill I downloaded that is not updated properly that is causing this. I might try wiping my desktop app?
Try sending your message again. If it keeps happening, share feedback so we can investigate.
Autocompact is thrashing: the context refilled to the limit within 3 turns of the previous compact, 3 times in a row. A file being read or a tool output is likely too large for the context window. Try reading in smaller chunks, or use /clear to start fresh.
You can restart the conversation from an earlier message.
Closing for now — inactive for too long. Please open a new issue if this is still relevant.
Im facing this issue on version 2.1.226 (Claude Code), was anyone able to fix this or found a workaround? When I check context usage with
/contextI get this<img width="428" height="374" alt="Image" src="https://github.com/user-attachments/assets/30ad0cf6-ac71-4f2d-b6a5-cfc8acd6cbae" />
I have tried
/clearand checked all the possible files I could but still same issueAutocompact is thrashing: the context refilled to the limit within 3 turns of the previous compact, 3 times in a row. A file being read or a tool output is likely too large for the context window. Try reading in smaller chunks, or use /clear to start fresh.I tried with claude --safe-mode as well but still same issue, on vs code extension as well CLI.
I think the issue is with how it handle auto compact, that has corrupted for one of my projects, it is working fine on other projects and, when I tried with auto compact disable on current project, its working fine and I am also monitoring the usage and that looks normal as well.
I found the root cause, somehow this got added by claude code to my
settings.local.json"env": {"CLAUDE_AUTOCOMPACT_PCT_OVERRIDE": "5"
},