http-fastapi-agent.md

FastAPI HTTP Agent Example

This example shows the HTTP endpoint contract without requiring your agent to be a subprocess. It is useful when your agent already runs as a web service.

Start the example endpoint:

uv run --with fastapi --with uvicorn \
  uvicorn examples.http_fastapi_agent.app:app --host 127.0.0.1 --port 8080

In another terminal, verify the endpoint contract:

uv run anvil conformance external-agent --url "http://127.0.0.1:8080/anvil"

Then run the scenario suite:

uv run anvil run scenarios/http_fastapi_agent.yaml --offline

The FastAPI app exposes POST /anvil. Agent Anvil sends the same scenario payload used by JSONL agents, and the endpoint returns an events list with model_call, tool_call, and final_output events.

The pure agent logic lives in examples/http_fastapi_agent/agent.py. The FastAPI wrapper lives in examples/http_fastapi_agent/app.py.