@ag-ui/client

Client SDK for connecting to Agent-User Interaction (AG-UI) Protocol servers.

@ag-ui/client provides agent implementations that handle the full lifecycle of AG-UI communication: connecting to servers, processing streaming events, managing state mutations, and providing reactive subscriber hooks.

Installation

npm install @ag-ui/client
pnpm add @ag-ui/client
yarn add @ag-ui/client

Features

• 🔗 HTTP connectivity – HttpAgent for direct server connections with SSE/protobuf support
• 🏗️ Custom agents – AbstractAgent base class for building your own transport layer
• 📡 Event streaming – Full AG-UI event processing with validation and transformation
• 🔄 State management – Automatic message/state tracking with reactive updates
• 🪝 Subscriber system – Middleware-style hooks for logging, persistence, and custom logic
• 🎯 Middleware support – Transform and filter events with function or class-based middleware

Quick example

import { HttpAgent } from "@ag-ui/client";

const agent = new HttpAgent({
  url: "https://api.example.com/agent",
  headers: { Authorization: "Bearer token" },
});

const result = await agent.runAgent({
  messages: [{ role: "user", content: "Hello!" }],
});

console.log(result.newMessages);

Using Middleware

import { HttpAgent, FilterToolCallsMiddleware } from "@ag-ui/client";

const agent = new HttpAgent({
  url: "https://api.example.com/agent",
});

// Add middleware to transform or filter events
agent.use(
  // Function middleware for logging
  (input, next) => {
    console.log("Starting run:", input.runId);
    return next.run(input);
  },

  // Class middleware for filtering tool calls
  new FilterToolCallsMiddleware({
    allowedToolCalls: ["search", "calculate"]
  })
);

await agent.runAgent();

Documentation

• Concepts & architecture: docs/concepts
• Full API reference: docs/sdk/js/client

Contributing

Bug reports and pull requests are welcome! Please read our contributing guide first.

License

MIT © 2025 AG-UI Protocol Contributors