Flue
The agent harness framework — build autonomous agents with TypeScript, deploy anywhere from Node.js to Cloudflare Workers
Overview
Flue is the agent harness framework from Fred K. Schott (Astro co-founder), introduced in May 2026 as a TypeScript framework for building truly autonomous agents. Unlike simple chatbots, Flue agents maintain context across conversations and work toward goals autonomously. It's runtime-agnostic — think Astro or Next.js, but for agents — letting you write once and deploy to Node.js, Cloudflare Workers, GitHub Actions, GitLab CI/CD, and more. Flue is 100% headless and programmable with no TUI, no GUI, and no assumption of a human operator. Most agent logic lives in Markdown (skills, context, AGENTS.md), keeping TypeScript code minimal.
The Verdict
Who Should Use Flue?
Best For
- Teams building headless, programmable agents for CI/CD
- Developers wanting Astro-like DX for agent development
- Projects needing multi-runtime deployment (Node, Cloudflare, etc.)
- Organizations requiring sandboxed, secure agent execution
- Teams preferring Markdown-first agent configuration
Not Ideal For
- Users wanting interactive TUI/GUI experiences
- Simple chatbot use cases
- Python-only teams (though PyFlue exists)
- Quick prototyping without deployment needs
What's Great
- From Astro team — proven DX expertise
- Runtime-agnostic: Node.js, Cloudflare, GitHub Actions, GitLab CI
- Built-in sandboxes for secure agent execution
- Durable execution — progress survives failures and restarts
- MCP server integration out of the box
- OpenTelemetry, Braintrust, Sentry observability
- Slack, Teams, Discord, GitHub chat integrations
- PyFlue port available for Python teams
Watch Out For
- No TUI/GUI — fully headless by design
- Requires Node.js 22.18.0+
- Newer framework (launched May 2026)
- TypeScript-focused (Python port separate)
Pricing
View all features & details
Core Concepts
- Agents — autonomous goal-driven workers
- Workflows — structured automations
- Sandboxes — secure execution environments
- Subagents — specialized delegation
- Tools — typed API actions
- Skills — reusable expertise packages
CLI Commands
- flue dev — watch-mode dev server
- flue run — one-shot CI invocations
- flue build — deployable artifacts
- flue connect — connect to agent
Deploy Targets
- Node.js
- Cloudflare Workers
- GitHub Actions
- GitLab CI/CD
- Daytona
- Render
LLM Providers
- Anthropic Claude
- OpenAI
- Google Gemini
- Moonshot Kimi
- OpenRouter (any model)
How It Compares
| Feature | Flue | Pi | Claude Code | LangChain |
|---|---|---|---|---|
| Philosophy | Headless framework | Minimal harness | Interactive CLI | SDK |
| Deploy Targets | 6+ runtimes | Local only | Local only | Varies |
| Sandboxes | Built-in | No | No | No |
| MCP Support | Native | Extension | Native | Plugin |
| Durable Execution | Yes | No | No | No |
| GitHub Stars | 4.9K | 62K | 30K+ | 100K+ |