The agent is the easy part — here's the rest of the stack

What it does

It’s a complete, working reference stack for serving an AI agent: a LangGraph agent behind a FastAPI service (streaming and non-streaming endpoints), a Python AgentClient for talking to that service, and a Streamlit chat app built on the client. Multiple agents can live in one service, addressed by URL path, with /info describing what’s available. The intended use is as a template — copy an agent like research_assistant.py, register it in agents.py, and you have a served agent with a UI.

The interesting bit

The agent itself is deliberately unremarkable; the value is the plumbing. The service supports both token-level and message-level streaming — the README calls the approach novel — and it threads LangGraph’s human-in-the-loop interrupt() through an HTTP API, which is exactly the part most demos skip.

Key highlights

• LangGraph v1.0 features wired end-to-end: interrupt() human-in-the-loop, Command flow control, long-term memory via Store, and a langgraph-supervisor setup
• Multiple agents per service, addressed by URL path; a hosted demo lets you poke the UI before reading any code
• Extras included: a basic RAG agent on ChromaDB, Safeguard content moderation, star feedback piped into LangSmith, and voice input/output in the UI
• Runs as three Docker services (postgres, agent API, Streamlit app) with live reload; unit and integration tests cover the stack
• A small ecosystem already builds on it, including a Next.js frontend and PolyRAG

Caveats

• It’s a well-made template, not a product — the bundled agents are demos you’re expected to copy and modify
• Content moderation requires a separate Groq API key, and nothing runs without at least one LLM API key
• Per the README, tests currently only run in the non-Docker local setup

Verdict

If you’re starting a LangGraph project and would rather not reinvent service protocol, streaming, and UI plumbing, this is one of the better starting points around. If you’re outside the LangChain ecosystem or want a hosted platform, keep moving.