[BUG] WebSearch tool failing with model access error (claude-haiku-4-5-20251001)

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?

---
Title: WebSearch tool failing with model access error (claude-haiku-4-5-20251001)

Description:
The WebSearch tool has stopped working. Whenever I attempt a search, the tool returns a system error instead of search results. This started
happening on May 4th, 2026, though it was working fine the previous week.

Error Message:
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. Run /model to pick a
different model.

Steps to Reproduce:

1. Ask Claude to perform a web search (e.g., "What are the top news items for today?").
2. The WebSearch tool is called.
3. The tool returns the model access error listed above.

---

What Should Happen?

The WebSearch tool has stopped working. Whenever I attempt a search, the tool returns a system error instead of search results. This started
happening on May 4th, 2026, though it was working fine the previous week.

Error Messages/Logs

model access error (claude-haiku-4-5-20251001)

Steps to Reproduce

Steps to Reproduce:

1. Ask Claude to perform a web search (e.g., "What are the top news items for today?").
2. The WebSearch tool is called.
3. The tool returns the model access error listed above.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.128 (Claude Code)

Claude Code Version

2.1.128 (Claude Code)

Platform

Anthropic API

Operating System

Other Linux

Terminal/Shell

Other

Additional Information

This was working just fine last week