API Error: 400 Invalid 'user_id': string does not match pattern. Expected a string that matches the pattern '^[a-zA-Z0-9_-]+$'.

[anakein]

Yesterday everything was working perfectly. Today I tried to use it and that message keeps appearing all the time:
API Error: 400 Invalid 'user_id': string does not match pattern. Expected a string that matches the pattern '^[a-zA-Z0-9_-]+$'.
and dont work

clause code 2.1.129

[anakein]

/clear and /exit several times and work egain

[aattaran]

Confirmed bug. Cause: Claude Code 2.1.129+ started sending a metadata.user_id field whose value contains characters Anthropic's API rejects. The Anthropic API enforces the pattern ^[a-zA-Z0-9_-]+$ for user_id; any @, ., :, or other char fails it. Older Claude Code versions either didn't send it or sanitized it client-side.

Workarounds today:

1. Switch to a non-Anthropic backend — DeepSeek/OpenRouter/Fireworks ignore the metadata field per their docs, so the proxy in /deepseek mode doesn't trigger this. Run deepclaude (default = ds) or /deepseek mid-session.
2. Downgrade Claude Code to 2.1.128 if you specifically need anthropic-direct mode and don't want to use the proxy.

Planned fix: add a sanitizer in processAnthropicRequest that replaces invalid chars in metadata.user_id with _ before forwarding. Tracking as a follow-up commit. The recently-merged PR #26 already includes the architecture for per-path body modification, so the sanitizer is a small addition.