claude-code - 💡(How to fix) Fix [BUG] WebSearch tool fails with invalid_request_error — references deprecated model name claude-haiku-4-5-20251001 [1 comments, 2 participants]

API Error: 400 {                                                                                                                                                                                                 
  "error": {                                                                                                                                                                                                     
    "code": 400,                                                                                                                                                                                                 
    "message": "model_name 'claude-haiku-4-5-20251001' is not a valid LLM model.",                                                                                                                               
    "param": null,                                                                                                                                                                                               
    "type": "invalid_request_error"
  }
}

Steps to reproduce:
1. Open Claude Code ([claude.ai/code](http://claude.ai/code) or CLI)
2. Ask any question that triggers a WebSearch tool call (e.g., "search for X", or any research question)
3. Tool call fails immediately with the 400 error above

Expected behavior: Web search returns results.

Actual behavior: Every search fails. The error indicates the tool is internally invoking claude-haiku-4-5-20251001 as a sub-model, which is either deprecated, renamed, or no longer a valid model ID.

Impact: The WebSearch tool is completely unusable. The WebFetch tool appears to be affected by the same underlying issue in some invocations.

Environment:
- Model: claude-sonnet-4-6
- Platform: macOS (darwin 25.4.0)
- Date observed: May 4, 2026

Suspected root cause: The WebSearch tool appears to use a small/fast model internally to process search results. The model ID claude-haiku-4-5-20251001 hardcoded in the tool backend appears to no longer be
valid — possibly needs to be updated to claude-haiku-4-5 or the current equivalent