Cohere models reject 'strict' parameter in tool definitions (422)

[rvernica]

Bug

When sending tool/function calls to Cohere models (cohere/command-r-08-2024, cohere/command-r7b-12-2024) via OpenRouter, the request fails with a 422 error:

{
  "message": "unknown field: parameter 'strict' is not a valid field. For proper usage, please refer to https://docs.cohere.com/reference/chat"
}

Cause

OpenRouter appears to forward the OpenAI-style "strict": true field in tool/function definitions to Cohere's API. Cohere's API does not recognize strict as a valid parameter and rejects the request.

Cohere has its own equivalent (strict_tools), but the strict field on individual tool definitions is OpenAI-specific and should be stripped or translated when routing to Cohere.

Steps to reproduce

1. Send a chat completion request to cohere/command-r-08-2024 via OpenRouter
2. Include tools with function definitions that contain "strict": true
3. Cohere returns 422: unknown field: parameter 'strict' is not a valid field

Expected behavior

OpenRouter should strip or translate the strict parameter from tool definitions when routing to Cohere models, similar to how other provider-specific parameters are handled.

Environment

• OpenRouter API (via OpenAI-compatible endpoint)
• Models affected: cohere/command-r-08-2024, cohere/command-r7b-12-2024 (likely all Cohere models)
• Client: OpenClaw gateway (sends standard OpenAI-format tool definitions)