Installation

Each LangStage stage is its own PyPI package — install only the surfaces you want. They all share the langgraph-stream-parser core, which is pulled in automatically.

WebTerminalJupyterLabVS CodeReference agent

pip install langstage

pip install langstage-cli

pip install langstage-jupyter

pip install langstage-vscode   # the Python sidecar
# + install the extension (see the VS Code stage page)

pip install langstage-hermes

Requirements

• Python 3.11+ (the core supports 3.10+).
• Your agent's own dependencies — typically langgraph and, if you use it, deepagents. Real surfaces already depend on langgraph, so the keyless --demo works on a bare install.
• An API key for whatever model your agent uses (e.g. ANTHROPIC_API_KEY) — not required for --demo.

Verify it works — no key needed

langstage run --demo          # web UI at http://localhost:8050
langstage-cli --demo "hello"  # one-shot terminal reply

Both launch against a built-in deterministic echo agent (langgraph_stream_parser.demo.stub:graph), so a fresh install is provably working before you wire up a real agent.

Next: Quickstart →