WebSearch tool error: thinking is enabled but reasoning_content is missing

Bug Report

Problem

The WebSearch tool consistently returns a 400 error with the following message:

API Error: 400 {"error":{"type":"invalid_request_error","message":"thinking is enabled but reasoning_content is missing in assistant tool call message at index 2"}}

Environment

• Date: 2026-03-09
• Model: kimi-k2.5
• Platform: Darwin (macOS)

Affected Tools

• WebSearch - Returns 400 error
• WebFetch - Unable to access certain domains (e.g., GitHub)

Workaround

Using Bash tool with curl as an alternative works correctly:

curl -s "https://api.github.com/search/repositories?q=openclaw"

Expected Behavior

WebSearch should return search results without errors.

Steps to Reproduce

1. Use WebSearch tool with any query
2. Observe 400 error response

Example query that fails:

WebSearch: {"query": "OpenClaw AI agent framework"}