Tools and structured output

Function callingCopy Anchor Link

Describe your functions in tools. The model answers with the calls it wants; your code runs them and sends the results back.

const reply = await ai.chat.completions.create({
  model: "anthropic/claude-sonnet-5.5",
  max_tokens: 1024,
  messages: [{ role: "user", content: "How many holders does $NOVA have?" }],
  tools: [
    {
      type: "function",
      function: {
        name: "token_holders",
        description: "How many wallets hold a Solana token right now",
        parameters: {
          type: "object",
          properties: { mint: { type: "string" } },
          required: ["mint"],
        },
      },
    },
  ],
});

const call = reply.choices[0]?.message.tool_calls?.[0];

Tools work the same on Responses and on Messages, in each format's own shape. Each model's GET /models entry says what it supports.

Structured outputCopy Anchor Link

Ask for JSON that matches your schema with response_format:

{
  "response_format": {
    "type": "json_schema",
    "json_schema": {
      "name": "day_summary",
      "strict": true,
      "schema": {
        "type": "object",
        "properties": {
          "trades": { "type": "integer" },
          "volume_sol": { "type": "number" }
        },
        "required": ["trades", "volume_sol"],
        "additionalProperties": false
      }
    }
  }
}

Web searchCopy Anchor Link

Add :online to a model id and it searches the web first, then answers with what it found:

{
  "model": "google/gemini-3.8-flash:online",
  "messages": [{ "role": "user", "content": "What happened on Solana this week?" }],
  "max_tokens": 1024
}

Each search is charged at the model's search price (web_search in GET /models), on top of the tokens. Models with hosted web search and web fetch tools can use those too: they run in a loop, so set max_tool_calls to cap the steps and the reserve.

Tools we don't serveCopy Anchor Link

Nothing is kept between calls, so tools that keep files, memory or a sandbox, or that run other models inside a call, are refused with 400 tool_not_served:

• hosted code execution, shells and code interpreters
• file search, files, memory and the text editor tool
• image generation tools and tools that call other models (to make images, call POST /images)
• X search, which bills per post with no limit a request can set

Tools your code runs on its own machine always work.