Function calling Beta


Similar to the Chat Completions API, the Assistants API supports function calling. Function calling allows you to describe functions to the Assistants API and have it intelligently return the functions that need to be called along with their arguments.

## Quickstart

In this example, we'll create a weather assistant and define two functions,
`get_current_temperature` and `get_rain_probability`, as tools that the Assistant can call.
Depending on the user query, the model will invoke parallel function calling if using our
latest models released on or after Nov 6, 2023.
In our example that uses parallel function calling, we will ask the Assistant what the weather in
San Francisco is like today and the chances of rain. We also show how to output the Assistant’s response with streaming.

### Step 1: Define functions

When creating your assistant, you will first define the functions under the `tools` param of the assistant.

<CodeSample
    defaultLanguage="python"
    code={{
        python: `
from openai import OpenAI
client = OpenAI()
 
assistant = client.beta.assistants.create(
  instructions="You are a weather bot. Use the provided functions to answer questions.",
  model="gpt-4o",
  tools=[
    {
      "type": "function",
      "function": {
        "name": "get_current_temperature",
        "description": "Get the current temperature for a specific location",
        "parameters": {
          "type": "object",
          "properties": {
            "location": {
              "type": "string",
              "description": "The city and state, e.g., San Francisco, CA"
            },
            "unit": {
              "type": "string",
              "enum": ["Celsius", "Fahrenheit"],
              "description": "The temperature unit to use. Infer this from the user's location."
            }
          },
          "required": ["location", "unit"]
        }
      }
    },
    {
      "type": "function",
      "function": {
        "name": "get_rain_probability",
        "description": "Get the probability of rain for a specific location",
        "parameters": {
          "type": "object",
          "properties": {
            "location": {
              "type": "string",
              "description": "The city and state, e.g., San Francisco, CA"
            }
          },
          "required": ["location"]
        }
      }
    }
  ]
)
`.trim(),
        "node.js": `
const assistant = await client.beta.assistants.create({
  model: "gpt-4o",
  instructions:
    "You are a weather bot. Use the provided functions to answer questions.",
  tools: [
    {
      type: "function",
      function: {
        name: "getCurrentTemperature",
        description: "Get the current temperature for a specific location",
        parameters: {
          type: "object",
          properties: {
            location: {
              type: "string",
              description: "The city and state, e.g., San Francisco, CA",
            },
            unit: {
              type: "string",
              enum: ["Celsius", "Fahrenheit"],
              description:
                "The temperature unit to use. Infer this from the user's location.",
            },
          },
          required: ["location", "unit"],
        },
      },
    },
    {
      type: "function",
      function: {
        name: "getRainProbability",
        description: "Get the probability of rain for a specific location",
        parameters: {
          type: "object",
          properties: {
            location: {
              type: "string",
              description: "The city and state, e.g., San Francisco, CA",
            },
          },
          required: ["location"],
        },
      },
    },
  ],
});`.trim(),
    }}
/>

### Step 2: Create a Thread and add Messages

Create a Thread when a user starts a conversation and add Messages to the Thread as the user asks questions.

<CodeSample
    defaultLanguage="python"
    code={{
        python: `
thread = client.beta.threads.create()
message = client.beta.threads.messages.create(
  thread_id=thread.id,
  role="user",
  content="What's the weather in San Francisco today and the likelihood it'll rain?",
)
`.trim(),
        "node.js": `
const thread = await client.beta.threads.create();
const message = client.beta.threads.messages.create(thread.id, {
  role: "user",
  content: "What's the weather in San Francisco today and the likelihood it'll rain?",
});
`.trim(),
    }}
/>

### Step 3: Initiate a Run

When you initiate a Run on a Thread containing a user Message that triggers one or more functions,
the Run will enter a `pending` status. After it processes, the run will enter a `requires_action` state which you can
verify by checking the Run’s `status`. This indicates that you need to run tools and submit their outputs to the
Assistant to continue Run execution. In our case, we will see two `tool_calls`, which indicates that the
user query resulted in parallel function calling.


    Note that a runs expire ten minutes after creation. Be sure to submit your tool
    outputs before the 10 min mark.


You will see two `tool_calls` within `required_action`, which indicates the user query triggered parallel function calling.

<CodeSample
    defaultLanguage="json"
    code={{
        json: `
{
  "id": "run_qJL1kI9xxWlfE0z1yfL0fGg9",
  ...
  "status": "requires_action",
  "required_action": {
    "submit_tool_outputs": {
      "tool_calls": [
        {
          "id": "call_FthC9qRpsL5kBpwwyw6c7j4k",
          "function": {
            "arguments": "{\"location\": \"San Francisco, CA\"}",
            "name": "get_rain_probability"
          },
          "type": "function"
        },
        {
          "id": "call_RpEDoB8O0FTL9JoKTuCVFOyR",
          "function": {
            "arguments": "{\"location\": \"San Francisco, CA\", \"unit\": \"Fahrenheit\"}",
            "name": "get_current_temperature"
          },
          "type": "function"
        }
      ]
    },
    ...
    "type": "submit_tool_outputs"
  }
}
`.trim(),
    }}
/>
Run object truncated here for readability


How you initiate a Run and submit `tool_calls` will differ depending on whether you are using streaming or not,
although in both cases all `tool_calls` need to be submitted at the same time.
You can then complete the Run by submitting the tool outputs from the functions you called.
Pass each `tool_call_id` referenced in the `required_action` object to match outputs to each function call.

<ContentSwitcher
    initialValue="streaming"
    options={[
        {
            label: "With streaming",
            value: "streaming",
            content: ,
        },
        {
            label: "Without streaming",
            value: "without-streaming",
            content: ,
        },
    ]}
/>