StateLens

Chrome DevTools for AI Agents

StateLens is a local-first debugging workspace for AI applications. Inspect every node, state transition, tool call, prompt, and execution path in your LangGraph agents.

Quick Start

1. Install the SDK

cd sdk
uv sync --extra langgraph
# or: pip install -e ".[langgraph]"

2. Instrument your graph

from statelens import observe

app = graph.compile()
app = observe(app)  # ← one line, zero config

result = app.invoke({"messages": [...]})

3. Start the server

cd backend
uv sync
statelens-server

4. View your executions

Open http://localhost:8000/conversations

Architecture

SDK (writes)  →  SQLite (~/.statelens/statelens.db)  ←  Backend (reads)  →  Frontend (displays)

• SDK — instruments LangGraph via callbacks, writes events to SQLite
• Backend — FastAPI server, reads from the same SQLite, serves REST API
• Frontend — Next.js app (separate repo concern), consumes the REST API

Project Structure

statelens/
├── contracts/      # Shared schemas and API contracts
├── sdk/            # Python SDK (statelens-sdk package)
├── backend/        # FastAPI server (statelens-server package)
├── frontend/       # Next.js UI (managed by OpenCode)
├── examples/       # Example LangGraph apps
└── docs/           # Documentation

API Endpoints

Configuration

License

MIT