Installation¶

Requirements¶

Python: 3.10, 3.11, or 3.12
pytest: 7.0 or newer (already a runtime dependency)

Install from PyPI¶

CoreWith FastAPIDevelopment

pip install agent-grammar

Installs the pytest plugin, AgentTestClient, the markdown renderer, the agent-grammar CLI, and a Starlette-based GrammarRouter for serving the compiled workflows.

pip install "agent-grammar[fastapi]"

Adds FastAPI as a hard dependency. Use this if your service is FastAPI- based and you want to mount GrammarRouter directly into your app.

pip install -e ".[dev]"

Editable install with pytest-cov, mypy, and ruff for local development of agent-grammar itself.

Verify the install¶

Check that the CLI is on your PATH:

agent-grammar --help

Confirm the pytest plugin auto-loaded:

pytest --help | grep agent-grammar

You should see the --agent-grammar-output and --agent-grammar-disable options listed. The plugin is registered through the pytest11 entry point and is discovered automatically once agent-grammar is installed — no conftest.py change required.

Smoke-test the import:

python -c "from agent_grammar import AgentTestClient, step_boundary, workflow; print('ok')"

What gets installed¶

Component	Provided by	Used for
`agent_grammar.workflow`	Python API	Decorate pytest tests to mark them as workflows.
`agent_grammar.step_boundary`	Python API	Annotate non-HTTP steps inside a workflow.
`agent_grammar.AgentTestClient`	Python API	Drop-in replacement for Starlette's `TestClient` that captures HTTP traffic.
`agent_grammar.serve.fastapi.GrammarRouter`	Python API	Mount the compiled `workflows.md` on a versioned route.
`agent_grammar.serve.fastapi.AgentTelemetryMiddleware`	Python API	Detect agent-driven requests via the `X-Agent-Grammar-Workflow` header.
`agent-grammar` CLI	Console script	Export Claude/Cursor/Copilot/Gemini system-prompt files.
pytest plugin	Entry point	Adds `--agent-grammar-output` / `--agent-grammar-disable` and writes the markdown after the session.

Next step¶

Head to the Walkthrough to clone the demo project, generate a workflows.md, and see the end-to-end loop.