WebSearch tool broken: internal model claude-haiku-4-5@20251001 not found

Bug Report

Claude Code version: 2.1.174
OS: Windows 10 Pro 10.0.19045
Model in use: claude-opus-4-8

Description

The WebSearch tool consistently fails with the following error:

There's an issue with the selected model (claude-haiku-4-5@20251001). It may not exist or you may not have access to it.

This error occurs regardless of which primary model is selected (switching to Opus 4.8 does not fix it). The internal small model used by WebSearch appears to be hardcoded to claude-haiku-4-5@20251001, which seems to be an invalid or deprecated model ID.

Steps to Reproduce

1. Open Claude Code (any version, confirmed on 2.1.141 and 2.1.174 after update)
2. Ask any question that triggers a WebSearch tool call
3. WebSearch returns the error above instead of results

Expected Behavior

WebSearch should return search results.

Additional Notes

• Updating from 2.1.141 to 2.1.174 did not fix the issue
• The modelOverrides setting in settings.json does not provide a way to override the internal WebSearch model
• WebFetch was also affected by the same error in an earlier session