Function calling for open models Stay organized with collections Save and categorize content based on your preferences.

Python

Before trying this sample, follow the Python setup instructions in the Agent Platform quickstart using client libraries.

To authenticate to Agent Platform, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

Before running this sample, make sure to set the OPENAI_BASE_URL environment variable. For more information, see Authentication and credentials.

from openai import OpenAI
client = OpenAI()

response = client.chat.completions.create(
  model="MODEL",
  messages=[
    {"role": "user", "content": "CONTENT"}
  ],
  tools=[
    {
      "type": "function",
      "function": {
        "name": "FUNCTION_NAME",
        "description": "FUNCTION_DESCRIPTION",
        "parameters": PARAMETERS_OBJECT,
      }
    }
  ],
  tool_choice="auto",
)

• MODEL: The model name you want to use, for example qwen/qwen3-next-80b-a3b-instruct-maas.
• CONTENT: The user prompt to send to the model.
• FUNCTION_NAME: The name of the function to call.
• FUNCTION_DESCRIPTION: A description of the function.
• PARAMETERS_OBJECT: A dictionary that defines the function parameters, for example:
  {"type": "object", "properties": {"location": {"type": "string", "description": "The city and state"}}, "required": ["location"]}

REST

Before using any of the request data, make the following replacements:

• PROJECT_ID: Your Google Cloud project ID.
• LOCATION: A region that supports open models.
• MODEL: The model name you want to use, for example qwen/qwen3-next-80b-a3b-instruct-maas.
• CONTENT: The user prompt to send to the model.
• FUNCTION_NAME: The name of the function to call.
• FUNCTION_DESCRIPTION: A description of the function.
• PARAMETERS_OBJECT: A JSON schema object that defines the function parameters, for example:
  {"type": "object", "properties": {"location": {"type": "string", "description": "The city and state"}}, "required": ["location"]}

HTTP method and URL:

POST https://LOCATION-aiplatform.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/endpoints/openapi/chat/completions

Request JSON body:

{
  "model": "MODEL",
  "messages": [
    {
      "role": "user",
      "content": "CONTENT"
    }
  ],
  "tools": [
    {
      "type": "function",
      "function": {
        "name": "FUNCTION_NAME",
        "description": "FUNCTION_DESCRIPTION",
        "parameters": PARAMETERS_OBJECT
      }
    }
  ],
  "tool_choice": "auto"
}

To send your request, choose one of these options:

curl -X POST \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     -H "Content-Type: application/json; charset=utf-8" \
     -d @request.json \
     "https://LOCATION-aiplatform.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/endpoints/openapi/chat/completions"

$cred = gcloud auth print-access-token
$headers = @{ "Authorization" = "Bearer $cred" }

Invoke-WebRequest `
    -Method POST `
    -Headers $headers `
    -ContentType: "application/json; charset=utf-8" `
    -InFile request.json `
    -Uri "https://LOCATION-aiplatform.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/endpoints/openapi/chat/completions" | Select-Object -Expand Content

You should receive a successful status code (2xx) and an empty response.

Python

from openai import OpenAI
client = OpenAI()

response = client.chat.completions.create(
  model="qwen/qwen3-next-80b-a3b-instruct-maas",
  messages=[
    {
      "role": "user",
      "content": "Which city has a higher temperature, Boston or new Delhi and by how much in F?"
    },
    {
      "role": "assistant",
      "content": "I'll check the current temperatures for Boston and New Delhi in Fahrenheit and compare them. I'll call the weather function for both cities.",
      "tool_calls": [{"function":{"arguments":"{\"location\":\"Boston, MA\",\"unit\":\"fahrenheit\"}","name":"get_current_weather"},"id":"get_current_weather","type":"function"},{"function":{"arguments":"{\"location\":\"New Delhi, India\",\"unit\":\"fahrenheit\"}","name":"get_current_weather"},"id":"get_current_weather","type":"function"}]
    },
    {
      "role": "tool",
      "content": "The temperature in Boston is 75 degrees Fahrenheit.",
      "tool_call_id": "get_current_weather"
    },
    {
      "role": "tool",
      "content": "The temperature in New Delhi is 50 degrees Fahrenheit.",
      "tool_call_id": "get_current_weather"
    }
  ],
  tools=[
    {
      "type": "function",
      "function": {
        "name": "get_current_weather",
        "description": "Get the current weather in a given location",
        "parameters": {
          "type": "object",
          "properties": {
            "location": {
              "type": "string",
              "description": "The city and state, e.g. San Francisco, CA"
            },
            "unit": {
              "type": "string",
              "enum": ["celsius", "fahrenheit"]
            }
          },
          "required": ["location"]
        }
      }
    }
  ],
  tool_choice="auto"
)

curl

curl -X POST \
-H "Authorization: Bearer $(gcloud auth print-access-token)" \
-H "Content-Type: application/json" \
https://us-central1-aiplatform.googleapis.com/v1/projects/sample-project/locations/us-central1/endpoints/openapi/chat/completions -d \
'{
  "model": "qwen/qwen3-next-80b-a3b-instruct-maas",
  "messages": [
    {
      "role": "user",
      "content": "Which city has a higher temperature, Boston or new Delhi and by how much in F?"
    },
    {
      "role": "assistant",
      "content": "I'll check the current temperatures for Boston and New Delhi in Fahrenheit and compare them. I'll call the weather function for both cities.",
      "tool_calls": [{"function":{"arguments":"{\"location\":\"Boston, MA\",\"unit\":\"fahrenheit\"}","name":"get_current_weather"},"id":"get_current_weather","type":"function"},{"function":{"arguments":"{\"location\":\"New Delhi, India\",\"unit\":\"fahrenheit\"}","name":"get_current_weather"},"id":"get_current_weather","type":"function"}]
    },
    {
      "role": "tool",
      "content": "The temperature in Boston is 75 degrees Fahrenheit.",
      "tool_call_id": "get_current_weather"
    },
    {
      "role": "tool",
      "content": "The temperature in New Delhi is 50 degrees Fahrenheit.",
      "tool_call_id": "get_current_weather"
    }
  ],
  "tools": [
    {
      "type": "function",
      "function": {
        "name": "get_current_weather",
        "description": "Get the current weather in a given location",
        "parameters": {
          "type": "object",
          "properties": {
            "location": {
              "type": "string",
              "description": "The city and state, e.g. San Francisco, CA"
            },
            "unit": {
              "type": "string",
              "enum": ["celsius", "fahrenheit"]
            }
          },
          "required": ["location"]
        }
      }
    }
  ],
  "tool_choice": "auto"
}'

{
 "choices": [
  {
   "finish_reason": "stop",
   "index": 0,
   "logprobs": null,
   "message": {
    "content": "Based on the current weather data:\n\n- **Boston, MA**: 75F
    \n- **New Delhi, India**: 50F  \n\n**Comparison**:
    \nBoston is **25F warmer** than New Delhi.  \n\n**Answer**:
    \nBoston has a higher temperature than New Delhi by 25 degrees Fahrenheit.",
    "role": "assistant"
   }
  }
 ],
 "created": 1750450289,
 "id": "2025-06-20|13:11:29.240295-07|6.230.75.101|-987540014",
 "model": "qwen/qwen3-next-80b-a3b-instruct-maas",
 "object": "chat.completion",
 "system_fingerprint": "",
 "usage": {
  "completion_tokens": 66,
  "prompt_tokens": 217,
  "total_tokens": 283
 }
}