Open Agent SDK

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

hljs language-perl

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, parsing, XML injection)
└── examples/
    └── coding-agent/       # Complete coding agent example

Quick Start

hljs language-bash

pnpm install
pnpm build
pnpm test

`oa` — Standalone CLI Agent

A terminal coding agent you can install globally and run from any directory. Session persistence, auto-compaction, streaming, skill discovery — all built in.

hljs language-bash

# Run directly from source (dev):
AI_GATEWAY_API_KEY=... pnpm --filter @open-agent-sdk/cli start

# Or build and install globally:
pnpm --filter @open-agent-sdk/cli build
npm i -g @open-agent-sdk/cli
oa                # start or resume a session
oa --new          # fresh session
oa --model openai/gpt-4o   # use a different model

# Or compile a standalone binary (requires bun):
pnpm --filter @open-agent-sdk/cli compile
./packages/cli/dist/oa     # no runtime needed

Run the example coding agent

A full-featured terminal chatbot with session persistence, auto-compaction, and streaming — in ~100 lines of code.

hljs language-bash

# Copy .env and set AI_GATEWAY_API_KEY to your Vercel AI Gateway token
cp examples/coding-agent/.env examples/coding-agent/.env.local
AI_GATEWAY_API_KEY=... pnpm --filter @open-agent-sdk/example-coding-agent chatbot
# start a fresh session:
AI_GATEWAY_API_KEY=... pnpm --filter @open-agent-sdk/example-coding-agent chatbot --new

Run a single-task agent

hljs language-bash

AI_GATEWAY_API_KEY=... pnpm --filter @open-agent-sdk/example-coding-agent start "Count lines of code in src/"

Complete Example

hljs language-typescript

import { gateway } from "ai";
import { runAgent, stepCountIs } from "@open-agent-sdk/core";
import { LocalSandbox } from "@open-agent-sdk/sandbox-local";
import { createAgentTools } from "@open-agent-sdk/tools";
import { discoverSkills, skillsToXml } from "@open-agent-sdk/skills";

// Works with any Vercel AI SDK provider — swap gateway() for openai(), google(), etc.
const model = gateway("anthropic/claude-sonnet-4.6");

const sandbox = new LocalSandbox({ cwd: process.cwd() });
const { tools } = createAgentTools(sandbox);

const skills = await discoverSkills();
const system = `You are an AI agent.\n\n${skillsToXml(skills)}`;

for await (const event of runAgent({
  model,
  tools,
  system,
  messages: "Summarize this codebase.",
  stopWhen: stepCountIs(10),
  stream: true,
})) {
  if (event.type === "text-delta") process.stdout.write(event.delta);
  if (event.type === "done") console.log(`\nDone in ${event.steps} steps.`);
}

Packages

`@open-agent-sdk/core`

Core interfaces and the agent loop.

Sandbox interface — uniform API for local and cloud execution environments
runAgent(options) — async generator that yields AgentEvents as the agent acts
stepCountIs(n), budgetExceeded(fn), composeStops(...fns) — stop conditions
cached(tool, name, options?) — LRU cache wrapper for any tool
compactConversation(config, state) — token-budget context compaction
middleTruncate(text, maxLength) — truncate long strings for display

hljs language-typescript

import { runAgent, stepCountIs } from "@open-agent-sdk/core";

for await (const event of runAgent({ model, tools, messages: "Hello!" })) {
  if (event.type === "done") console.log(event.text);
}

`@open-agent-sdk/sandbox-local`

Local sandbox that runs commands via child_process and accesses the real filesystem.

hljs language-typescript

import { LocalSandbox } from "@open-agent-sdk/sandbox-local";

const sandbox = new LocalSandbox({ cwd: "/my/project" });
const result = await sandbox.exec("ls -la");

`@open-agent-sdk/sandbox-e2b`

Cloud sandbox backed by E2B. Requires @e2b/code-interpreter as a peer dependency.

hljs language-typescript

import { E2BSandbox } from "@open-agent-sdk/sandbox-e2b";

const sandbox = new E2BSandbox({ apiKey: process.env.E2B_API_KEY });

`@open-agent-sdk/sandbox-vercel`

Cloud sandbox backed by Vercel Firecracker. Requires @vercel/sandbox as a peer dependency.

hljs language-typescript

import { VercelSandbox } from "@open-agent-sdk/sandbox-vercel";

const sandbox = new VercelSandbox({ runtime: "node22" });

`@open-agent-sdk/tools`

Standard agent tools built on the Sandbox interface.

Tool	Description
`createBashTool(sandbox)`	Run shell commands with timeout and output truncation
`createReadTool(sandbox)`	Read files with line numbers, offset/limit pagination
`createWriteTool(sandbox)`	Write files with parent directory creation
`createEditTool(sandbox)`	Targeted string replacement in files
`createGlobTool(sandbox)`	Glob pattern file search
`createGrepTool(sandbox)`	Regex content search (with ripgrep when available)
`createAskUserTool()`	Pause agent to ask the user a question
`createEnterPlanModeTool(state)`	Enter planning mode
`createExitPlanModeTool(state)`	Exit planning mode with a plan
`createTodoWriteTool(state)`	Track task progress
`createTaskTool(config)`	Spawn sub-agents for parallel/isolated work

The createAgentTools(sandbox, config?) convenience factory creates all tools in one call:

hljs language-typescript

import { createAgentTools } from "@open-agent-sdk/tools";

const { tools, planModeState, todoState } = createAgentTools(sandbox, {
  tools: { Bash: { timeout: 30_000 } },
});

`@open-agent-sdk/tools-web`

Web tools backed by parallel-web. Install this package when you need WebSearch or WebFetch.

hljs language-typescript

import { createWebSearchTool, createWebFetchTool } from "@open-agent-sdk/tools-web";

const webSearch = createWebSearchTool();
const webFetch = createWebFetchTool();

`@open-agent-sdk/cli`

Standalone CLI coding agent — oa. Install globally or compile to a standalone binary.

hljs language-bash

npm i -g @open-agent-sdk/cli
oa              # interactive agent in current directory
oa --new        # fresh session
oa --help       # show all options

Features: session persistence (.session.jsonl), auto-compaction, skill discovery, configurable model via --model.

`@open-agent-sdk/skills`

Agent Skills standard — composable behavior modules loaded from SKILL.md files.

hljs language-typescript

import { discoverSkills, skillsToXml, setupAgentEnvironment } from "@open-agent-sdk/skills";

// Discover skills from .skills/ and ~/.agents/skills/
const skills = await discoverSkills();

// Inject into system prompt as XML
const systemPrompt = `You are an AI agent.\n\n${skillsToXml(skills)}`;

// Or set up a sandbox workspace with skill files
await setupAgentEnvironment(sandbox, { skills });

Open Agent SDK vs Claude Agent SDK

	Open Agent SDK	Claude Agent SDK
LLM providers	Any (OpenAI, Anthropic, Google, Mistral, …)	Anthropic only
Open source	Yes (MIT)	No
Package architecture	Modular — install only what you need	Monolithic
Sandbox	Local, E2B, Vercel, or custom	Managed (opaque)
Agent loop	Transparent, extensible	Internal, black-box
Built on	Vercel AI SDK (standard)	Proprietary runtime

Development

hljs language-bash

pnpm build          # Build all packages
pnpm test           # Run all tests (105 tests across 8 packages)
pnpm -r typecheck   # Type-check all packages

License

MIT

open-agent-sdk

Open Agent SDK

Features

Architecture

Quick Start

`oa` — Standalone CLI Agent

Run the example coding agent

Run a single-task agent

Complete Example

Packages

`@open-agent-sdk/core`

`@open-agent-sdk/sandbox-local`

`@open-agent-sdk/sandbox-e2b`

`@open-agent-sdk/sandbox-vercel`

`@open-agent-sdk/tools`

`@open-agent-sdk/tools-web`

`@open-agent-sdk/cli`

`@open-agent-sdk/skills`

Open Agent SDK vs Claude Agent SDK

Development

License

Similar Packages

Repository

Tags

Original Author

Publisher

Repository

open-agent-sdk

Open Agent SDK

Features

Architecture

Quick Start

oa — Standalone CLI Agent

Run the example coding agent

Run a single-task agent

Complete Example

Packages

@open-agent-sdk/core

@open-agent-sdk/sandbox-local

@open-agent-sdk/sandbox-e2b

@open-agent-sdk/sandbox-vercel

@open-agent-sdk/tools

@open-agent-sdk/tools-web

@open-agent-sdk/cli

@open-agent-sdk/skills

Open Agent SDK vs Claude Agent SDK

Development

License

Similar Packages

Repository

Tags

Original Author

Publisher

Repository

`oa` — Standalone CLI Agent

`@open-agent-sdk/core`

`@open-agent-sdk/sandbox-local`

`@open-agent-sdk/sandbox-e2b`

`@open-agent-sdk/sandbox-vercel`

`@open-agent-sdk/tools`

`@open-agent-sdk/tools-web`

`@open-agent-sdk/cli`

`@open-agent-sdk/skills`