supports_tools: true in GET /v1/models can call tools you define. Tools work on all three endpoints, in each API’s own format. You run the tool and send the result back in the next request.
Limits: up to 128 tools per request. Streamed tool calls arrive as argument deltas, which the SDK stream helpers assemble for you.
Built-in server tools (web search, file search, code execution, computer use) aren’t available; requests with them get
400 unsupported_parameter. Tools on a model without tool support get the same error.