vercel.ts

import "dotenv-flow/config"
import { stepCountIs, streamText, tool } from "ai"
import { langtail } from "../src/vercel-ai"
import { z } from "zod/v4"

async function main() {
  const result = streamText({
    model: langtail("vtip"),
    messages: [
      {
        role: "user",
        content: "What is the weather in Tokyo?",
      },
    ],
    stopWhen: stepCountIs(5),
    onStepFinish: (step) => {
      console.log(step.content)
    },
    tools: {
      weather: tool({
        description: "Get the weather in a location",
        inputSchema: z.object({
          location: z.string().describe("The location to get the weather for"),
        }),
        async execute({ location }) {
          return {
            type: "image",
            data: "https://stickerapp.co.uk/cdn-assets/images/stickers/608t.png",
          }
        },

        // map to tool result content for LLM consumption:
        toModelOutput(result) {
          return {
            type: "content",
            value:
              typeof result === "string"
                ? [{ type: "text", text: result }]
                : [
                    {
                      type: "media",
                      data: result.data,
                      mediaType: "image/png",
                    },
                  ],
          }
        },
      }),
    },
  })

  for await (const chunk of result.fullStream) {
    console.log("chunk", chunk)
  }
}

main()