@typia/vercel

Vercel AI SDK integration for typia.

Converts typia controllers to Vercel AI SDK tools compatible with OpenAI, Anthropic, Google, and other LLM providers.

Setup

npm install @typia/vercel ai typia
npm install -D ttsc typescript@rc

Usage

From TypeScript class

import { openai } from "@ai-sdk/openai";
import { toVercelTools } from "@typia/vercel";
import { generateText, GenerateTextResult, Tool } from "ai";
import typia from "typia";

const tools: Record<string, Tool> = toVercelTools(
  typia.llm.controller<Calculator>("Calculator", new Calculator()),
);

const result: GenerateTextResult = await generateText({
  model: openai("gpt-4o"),
  prompt: "What is 10 + 5?",
  tools,
});

From OpenAPI document

import { toVercelTools } from "@typia/vercel";
import { HttpLlm } from "@typia/utils";
import { Tool } from "ai";

const tools: Record<string, Tool> = toVercelTools(
  HttpLlm.controller({
    name: "petStore",
    document: yourOpenApiDocument,
    connection: { host: "https://api.example.com" },
  }),
);

Structured Output

Use typia.llm.parameters<T>() with Vercel's jsonSchema() to generate structured output with validation:

import { openai } from "@ai-sdk/openai";
import { generateObject, jsonSchema } from "ai";
import { dedent, LlmJson } from "@typia/utils";
import typia, { tags } from "typia";

interface IMember {
  email: string & tags.Format<"email">;
  name: string;
  age: number & tags.Minimum<0> & tags.Maximum<100>;
  hobbies: string[];
  joined_at: string & tags.Format<"date">;
}

const { object } = await generateObject({
  model: openai("gpt-4o"),
  schema: jsonSchema<IMember>(typia.llm.parameters<IMember>(), {
    validate: (value) => {
      const result = typia.validate<IMember>(value);
      if (result.success) return { success: true, value: result.data };
      return {
        success: false,
        error: new Error(LlmJson.stringify(result)),
      };
    },
  }),
  prompt: dedent`
    I am a new member of the community.

    My name is John Doe, and I am 25 years old.
    I like playing basketball and reading books,
    and joined to this community at 2022-01-01.
  `,
});

Features

• No manual schema definition — generates everything from TypeScript types or OpenAPI
• Automatic argument validation with LLM-friendly error feedback
• Reflected return types advertise the { success, data/error } output wrapper
• Runtime tool errors are returned as { success: false, error } for model recovery
• Supports both class-based (typia.llm.controller) and HTTP-based (HttpLlm.controller) controllers
• Works with any LLM provider supported by Vercel AI SDK