Overview | TanStack AI Docs

TanStack AI is a lightweight, type-safe SDK for building production-ready AI experiences. Its framework-agnostic core provides type-safe tool/function calling, streaming responses, and first-class React and Solid integrations, with adapters for multiple LLM providers — enabling predictable, composable, and testable AI features across any stack.

Key Features

✅ Type-Safe - Full TypeScript support with Zod schema inference
✅ Streaming - Built-in streaming support for real-time responses
✅ Isomorphic Tools - Define once with toolDefinition(), implement with .server() or .client()
✅ Framework Agnostic - Core library works anywhere
✅ Multiple Providers - OpenAI, Anthropic, Gemini, Ollama, and more
✅ Approval Flow - Built-in support for tool approval workflows
✅ Automatic Execution - Both server and client tools execute automatically

Framework Agnostic

The framework-agnostic core of TanStack AI provides the building blocks for creating AI experiences in any environment, including:

Next.js - API routes and App Router
TanStack Start - React Start or Solid Start (recommended!)
Express - Node.js server
Remix Router v7 - Loaders and actions

TanStack AI lets you define a tool once and provide environment-specific implementations. Using toolDefinition() to declare the tool’s input/output types and the server behavior with .server() (or a client implementation with .client()). These isomorphic tools can be invoked from the AI runtime regardless of framework.

typescript

import { toolDefinition } from '@tanstack/ai'

// Define a tool
const getProductsDef = toolDefinition({
  name: 'getProducts',
  inputSchema: z.object({ query: z.string() }),
  outputSchema: z.array(z.object({ id: z.string(), name: z.string() })),
})

// Create server implementation
const getProducts = getProductsDef.server(async ({ query }) => {
  return await db.products.search(query)
})

// Use in AI chat
chat({ tools: [getProducts] })

import { toolDefinition } from '@tanstack/ai'

// Define a tool
const getProductsDef = toolDefinition({
  name: 'getProducts',
  inputSchema: z.object({ query: z.string() }),
  outputSchema: z.array(z.object({ id: z.string(), name: z.string() })),
})

// Create server implementation
const getProducts = getProductsDef.server(async ({ query }) => {
  return await db.products.search(query)
})

// Use in AI chat
chat({ tools: [getProducts] })

Core Packages

The TanStack AI ecosystem consists of several packages:

@tanstack/ai

The core AI library that provides:

AI adapter interface for connecting to LLM providers
Chat completion and streaming
Isomorphic tool/function calling system
Agent loop strategies
Type-safe tool definitions with toolDefinition()
Type-safe provider options based on adapter & model selection
Type-safe content modalities (text, image, audio, video, document) based on model capabilities