Anthropic hosted web_search options are not mapped onto Grok #123

Environment

claude-code-proxy live grok-claude instance, 127.0.0.1:18765
Claude Code 2.1.220, VS Code extension
provider: grok
model: grok-4.6
Grok client version (proxy header): 0.2.93

Problem

Claude Code sends Anthropic hosted web_search_20250305 options. The Grok path does not map them onto Grok hosted web_search.

Those options include allowed_domains, blocked_domains, user_location, and max_uses.

For domain lists and user_location, the proxy returns HTTP 400 before it calls Grok:

API Error: 400 Grok hosted web search does not support allowed_domains

Claude Code then retries the same search without the constraint. The search still runs, unrestricted, after an extra failed turn.

Also Grok does not support max_uses.

How to reproduce

Reliable replay against 127.0.0.1:18765:

curl -s -X POST 'http://127.0.0.1:18765/v1/messages?beta=true' \
  -H 'content-type: application/json' \
  -H 'anthropic-version: 2023-06-01' \
  -H 'authorization: Bearer unused' \
  -d '{
    "model": "grok-4.6",
    "max_tokens": 64,
    "stream": false,
    "messages": [{"role": "user", "content": "What are LangChain Deep Agents LangGraph 2026 tools"}],
    "tools": [{
      "type": "web_search_20250305",
      "name": "web_search",
      "max_uses": 8,
      "allowed_domains": ["langchain.com", "docs.langchain.com", "blog.langchain.com"]
    }]
  }'

Observed

1. Hosted search with allowed_domains returns HTTP 400. Grok is not called.
2. Claude Code presents the proxy error as a tool_result for the original WebSearch tool use, with is_error: true.
3. On the next assistant turn, the model retries the same topic without allowed_domains.
4. Those calls return search results.

Expected

The proxy maps Anthropic hosted-search options onto Grok where Grok has a matching field.

When Grok cannot enforce an option, the search still completes in one round. The request does not fail only for Claude Code to retry without the constraint.

Status: A fix is running in the fork AlexanderKugel/claude-code-proxy. A pull request will follow.