400 error: "tools.function.parameters is not a valid moonshot flavored json schema" when using custom API endpoint with MCP tools

[skydzx]

What version of Kimi Code is running?

0.23.6

Which open platform/subscription were you using?

Allegretto subscription

Which model were you using?

kimi-for-coding

What platform is your computer?

Windows 11 Home China 10.0.26200 x64

What issue are you seeing?

When using a custom API endpoint with multiple MCP servers configured,the LLM request fails with:
APIStatusError: 400 tools.function.parameters is not a valid moonshot flavored json schema, details: <At path 'properties.workFlow.items.required': required property 'codecType' is not defined in properties> At the time of the error, 255 tools were registered across multiple MCP servers. The Moonshot API appears to do stricter JSON Schema validation than standard OpenAI-compatible APIs.

What steps can reproduce the bug?

1. Configure multiple MCP servers (playwright, firecrawl, etc.)
2. Set a custom API endpoint
3. Send any prompt
4. Request fails before reaching the model

What is the expected behavior?

• Client-side schema validation to filter invalid tool schemas
  before sending
  • Or graceful degradation: retry with problematic tools removed
  • Or a clearer error message indicating which MCP server/tool
    caused the issue @

Additional information

One of the MCP tools has a "required" array referencing
"codecType" which is not defined in "properties" of that object.
This violates strict JSON Schema validation.

session_d40255e5-91fc-4529-821b-2a4835b2df2a.zip