[BUG] GCP Vertex has made a WebSearch tool available for Claude models as of 17th September, but Claude Code can't see it

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?

GCP Vertex has made a WebSearch tool available for Claude models as of 17th September, but Claude Code can't see it.

When I ask Claude to list available tools it lists the usual suspects (including e.g. 'WebFetch') but there's no sign of the new 'WebSearch'

What Should Happen?

Claude Code should be able to use GCP's newly integrated WebSearch tool when using Claude models in Vertex

Error Messages/Logs

Steps to Reproduce

Ask Claude Code, connected to models via Vertex and not Anthropic, to list its core tools

Claude Model

Not sure / Multiple models

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

1.0.117

Platform

Google Vertex AI

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_