Flue is the agent harness framework. If you know how to use Claude Code, Codex, or OpenCode, you already understand the basics — Flue gives you those same capabilities as a 100% headless, programmable TypeScript API. No TUI, no GUI, no baked-in human operator. Just TypeScript agents that run autonomously and deploy anywhere.Documentation Index
Fetch the complete documentation index at: https://mintlify.com/withastro/flue/llms.txt
Use this file to discover all available pages before exploring further.
Quickstart
Build and run your first agent in under five minutes.
Core concepts
Understand agents, harnesses, sessions, and sandboxes.
Writing agents
Learn the agent file format, triggers, and handler patterns.
CLI reference
Explore every
flue command: dev, run, build, add, logs.Why Flue?
Flue is a proper runtime-agnostic framework — think Astro or Next.js, but for agents. Write once, deploy anywhere. Agents require very little code; most of the “logic” lives in Markdown — skills, context, andAGENTS.md.
Virtual sandboxes
Run agents in a fast, cheap in-process sandbox (powered by just-bash) — no container needed for most use cases.
Remote sandboxes
Connect full Linux containers via Daytona, E2B, Cloudflare Containers, or any custom connector.
Persistent sessions
Sessions persist automatically on Cloudflare (Durable Objects) or in-memory on Node.js. Conversations survive across requests.
Typed results
Get schema-validated structured data back from any
prompt(), skill(), or task() call using Valibot schemas.MCP support
Connect to remote MCP servers and pass their tool lists directly to your agent harness.
Multi-target deploys
One codebase, multiple targets: Node.js server, Cloudflare Workers, GitHub Actions, GitLab CI.
Get started
Write your first agent
Create
.flue/agents/hello.ts and add a handler with triggers = { webhook: true }.Explore the docs
Sandboxes
Choose between virtual, local, or remote sandboxes for your agent.
Skills and roles
Shape agent behavior with reusable Markdown instruction sets.
Deploy to Cloudflare
Deploy agents as Cloudflare Workers with persistent Durable Object sessions.
API reference
Full TypeScript API documentation for
FlueContext, FlueHarness, and FlueSession.