[BUG] Title: 2.1.26x rejects >200K prompts on Max subscription ("Prompt is too long"); 2.1.257 serves the same 664K prompt
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 Max (claude.ai OAuth). Same resumed session, same 663,871-token prompt (~1.2 MB of @-injected files + history), same account, same day.
▎ - 2.1.257: served by claude-fable-5-1, 663,871 input tokens.
▎ - 2.1.269: API invalid_request: Prompt is too long on claude-fable-5-1, claude-fable-5, and claude-opus-4-8[1m] — the last of which carried this same conversation at
▎ 679,998 tokens on 2.1.197 (2026-07-01).
▎ - Not set: CLAUDE_CODE_DISABLE_1M_CONTEXT, ANTHROPIC_BETAS. CLAUDE_CODE_DISABLE_UNKNOWN_MODEL_WINDOW_ENFORCEMENT=1 made no difference. autoCompactEnabled: false.
▎ - Downgrading to 2.1.257 fixes it immediately. Suspect the 1M-context/Fable changes in v2.1.260–2.1.261. Same class as #43989 / #34158 / #11281.
What Should Happen?
Letting me continue a >200k token conversation the previous version did fine
Error Messages/Logs
⎿ Context limit reached · /compact or /clear to continue · auto-compact is off ·
/config to turn it on
Steps to Reproduce
Take the same >200k conversation without compacting and try to continue, with both installed, one launched with
~/.local/bin/claude-2.1.257
or equivalent, instead of claude (where it will work)
and another with ~/.local/bin/claude-2.1.269
where it will request a compact, essentially negating the 1M context feature of the models
Claude Model
None
Is this a regression?
Yes, this worked in a previous version
Last Working Version
2.1.257
Claude Code Version
2.1.269
Platform
Anthropic API
Operating System
Ubuntu/Debian Linux
Terminal/Shell
Terminal.app (macOS)
Additional Information
_No response_