[BUG] Web Fetch tool not handling same host redirects correctly

Environment

• Platform (select one):
• [ ] Anthropic API
• [x] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: <!-- output of claude --version -->
• Operating System: <!-- e.g. macOS 14.3, Windows 11, Ubuntu 22.04 -->
• Terminal: <!-- e.g. iTerm2, Terminal App -->

Bug Description

It appears that simple 301 redirects on the same host are being incorrectly rejected:

> Can you fetch https://plaid.com/docs/balance ?

⏺ I'll fetch that page for you.

⏺ Fetch(https://plaid.com/docs/balance)…
  ⎿  Error: Redirect not allowed. Only redirects to the same host are permitted.

Steps to Reproduce

1. Ask to fetch a URL that does a same-host redirect.

• Examples: https://plaid.com/docs/balance https://api-docs.incident.io/tag/Incidents-V2 - both of these 301 to the trailing slash variant, to Location: /docs/balance/ and Location: ./Incidents-V2/ respectively

1. Redirect is rejected

Expected Behavior

1. The redirect should work since it is same host

Actual Behavior

1. The redirect is rejected/not followed

Additional Context

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