The Open Agent Framework
Build durable AI agents with Flue's programmable TypeScript harness. Write once, deploy anywhere, use any LLM.
export function MyAssistant() {
const [count, setCount] = usePersistentState('count', 0);
useAgentStart(() => setCount((n) => n + 1));
useModel('moonshot/kimi-k2');
return `You are a helpful assistant. This conversation has ${count} messages.`;
}Powered by Pi, the open agent harness.
Flue is powered by Pi, the trusted agent harness used by OpenClaw and millions worldwide. Pi gives you the tools you need to unlock real agent autonomy, moving beyond simple chatbots.
Pi is the core of our open tech stack including Durable Streams, Vite, and a flexible Sandbox API. Deploy Flue anywhere with confidence.
Durability. Recovery. It's all handled for you.
Agents can’t die when the server goes down. Flue records every session in a durable stream, then safely resumes interrupted work when the runtime comes back online. Run one agent or a multi-agent swarm on the same durable foundation.
- Accepted work is never lost
- Interrupted sessions resume automatically
- Clients reconnect without starting over
Bring the stack you already love.
Explore our ecosystem →
Features
Build agents that can safely take action, maintain continuity, and connect to the systems where work already happens.
Agents
Build agents that can keep context across conversations and events as they autonomously work toward a goal. Each one is durable, stateful, and addressable over HTTP.
Workflows
Agents are just functions. Script them with flue run and the SDK — locally, in CI, or from your own backend — or orchestrate them with Cloudflare Workflows, Inngest, and more.
Sandboxes
A secure environment where agents run commands, edit files, and do real work.
Persistent State
Write data on each agent and update its capabilities as state changes.
Subagents
Define specialized roles and let your agent delegate work to the right expert.
Tools
Agents call APIs, query data, and make changes — using the code you define.
Skills
Package expertise that agents load whenever a task needs guidance.
MCP Servers
Connect agents to thousands of tools through the open Model Context Protocol.
Durable Execution
Work survives crashes, restarts, and deploys — sessions resume automatically.
Observability
Export session traces to OpenTelemetry, Braintrust, Sentry, or your own observer.
Chat
Connect agents to where work happens — Slack, Teams, Discord, GitHub, and more.
Explore the docs
Learn how to build, run, and deploy production-ready agents with Flue.