This mirrors the current Cookbook. The assistant first asks to call your function, then you return the result using function_call_result.

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1) Initial request (expose calculator)

curl -X POST "https://api.incredible.one/v1/chat-completion" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $INCREDIBLE_API_KEY" \
  -d '{
    "model": "small-1",
    "stream": false,
    "messages": [{"role": "user", "content": "What is 127 + 349?"}],
    "functions": [{
      "name": "calculate_sum",
      "description": "Add two numbers together and return the sum",
      "parameters": {
        "type": "object",
        "properties": {
          "a": {"type": "number"},
          "b": {"type": "number"}
        },
        "required": ["a", "b"]
      }
    }]
  }'
The response includes a type: "function_call" with function_call_id and arguments.

​
2) Follow-up with the result

curl -X POST "https://api.incredible.one/v1/chat-completion" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $INCREDIBLE_API_KEY" \
  -d '{
    "model": "small-1",
    "stream": false,
    "messages": [
      {"role": "user", "content": "What is 127 + 349?"},
      {"type": "function_call", "function_call_id": "CALL_ID_FROM_STEP_1", "function_calls": [{
        "name": "calculate_sum", "input": {"a": 127, "b": 349}
      }]},
      {"type": "function_call_result", "function_call_id": "CALL_ID_FROM_STEP_1", "function_call_results": [476]}
    ],
    "functions": [{
      "name": "calculate_sum",
      "description": "Add two numbers together and return the sum",
      "parameters": {
        "type": "object",
        "properties": {"a": {"type": "number"}, "b": {"type": "number"}},
        "required": ["a", "b"]
      }
    }]
  }'
View source on GitHub → 1_simple_calculator.py