[BUG] [claude.ai] Compaction fails silently on web/desktop/mobile — related to #16349

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?

This bug affects claude.ai (web, desktop, mobile PWA), not Claude Code. I'm reporting here because the root cause appears related to #16349 and there's no dedicated repository for claude.ai issues.

Conversations silently reject new messages at ~100-120k tokens. No compaction triggers. No error message. Messages vanish as if never sent. Status page shows "All Operational" since January 15 while the problem persists.

What Should Happen?

Automatic compaction should trigger before context saturation. If compaction fails, users should receive a clear error message — not silent rejection.

Error Messages/Logs

No error message displayed. This is part of the bug — messages silently disappear with no feedback to user.

Steps to Reproduce

1. Open claude.ai (web, desktop, or mobile)
2. Start a conversation with substantial context (Projects with knowledge files, or long exchanges)
3. Continue until ~100-120k tokens
4. Send a new message
5. Message vanishes — no error, no compaction, no feedback

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Worked before January 15, 2026

Claude Code Version

N/A — this affects claude.ai, not Claude Code

Platform

Other

Operating System

Windows

Terminal/Shell

Other

Additional Information

• Max plan subscriber ($100+/month)
• Tested across: claude.ai web, Claude Desktop, mobile PWA
• Tested with code execution ON and OFF — same result
• January 15 incident marked "Resolved" but problem persists
• Related: #16349 (identical warning/error thresholds)
• Support contacted multiple times, no response after 6 days
• Multiple users reporting same issue on Reddit r/ClaudeAI

Please forward to the appropriate team if claude.ai issues are out of scope for this repository.