Tools

Close the loop between model planning and deterministic function execution.

Tool Definition

TypeScript

const tools = [{
  type: "function",
  function: {
    name: "get_weather",
    description: "Return weather by city",
    parameters: {
      type: "object",
      properties: { city: { type: "string" } },
      required: ["city"],
    },
  },
}];

Tool Call Item

Name	Type	Required	Description
name	string	Required	Tool function name.
arguments	object	Required	JSON arguments payload.
call_id	string	Required	Unique tool invocation ID.
status	string		pending \| executed \| failed

Execute + Return Result

tool-loop.ts

for (const item of result.items) {
  if (item.type !== "tool_call") continue;
  const output = await handlers[item.name](item.arguments);
  await client.callModel({
    ...result.next_turn,
    input: [{ type: "tool_result", call_id: item.call_id, output }],
  });
}

Validation first

Validate tool arguments against your schema before execution to prevent malformed or unsafe calls.