TypeScript AI SDK for building AI agents with any LLM — OpenAI, Claude, Gemini & more. Open-source alternative to Claude Agent SDK.

Open Agent SDK

Open-source TypeScript SDK for building AI agents — a provider-agnostic, modular alternative to the Gemini Agent SDK.

Built on the Vercel AI SDK (v6+), so it works with any LLM: Anthropic Claude, OpenAI GPT, Google Gemini, Mistral, and more.

Why Open Agent SDK? The official Gemini Agent SDK is powerful but vendor-locked and opaque. Open Agent SDK gives you the same agent loop capabilities — tool use, multi-step reasoning, sub-agents, context compaction — with full control, any LLM provider, and an install-only-what-you-need package architecture.

Features

• Provider-agnostic — swap between Gemini, GPT-4, Gemini, or any Vercel AI SDK provider
• Modular packages — use only what you need; no mandatory cloud dependencies
• Sandbox-agnostic — run locally, on E2B, on Vercel Firecracker, or bring your own
• Full TypeScript — strict types, Zod schemas, generic type parameters throughout
• Agent loop built-in — step management, budget tracking, context compaction, stop conditions
• Sub-agent support — spawn isolated agents for parallel or delegated work
• Skills system — composable behavior modules via the Agent Skills standard
• Tool caching — LRU cache wrapper for any tool, out of the box

Architecture

open-agent-sdk/
├── packages/
│   ├── core/               # Agent loop, types, caching, utilities
│   ├── sandbox-local/      # Local filesystem + shell sandbox
│   ├── sandbox-e2b/        # E2B cloud sandbox
│   ├── sandbox-vercel/     # Vercel Firecracker sandbox
│   ├── cli/                # `oa` — standalone CLI coding agent
│   ├── tools/              # Standard agent tools (Bash, Read, Write, Edit, Glob, Grep, …)
│   ├── tools-web/          # Web tools (WebSearch, WebFetch) via parallel-web
│   └── skills/             # Agent Skills standard (discovery, parsin