Serve a project

From the agent folder, compile and start the standalone development server:

harnest serve .

Send a message from another terminal:

curl --fail-with-body -sS http://127.0.0.1:1907/responses \
  -H 'Content-Type: application/json' \
  -d '{"input":"Hello! What can you help me with?"}'

The response includes outputText and a sessionId you can reuse. See API requests and streaming examples for the request fields, typed inputs, authentication, and SSE. Startup output lists the Swagger URL and downloadable openapi.json / openapi.yaml resources. Calling agents can discover those resources through /agent. Set server.openapi: false to hide them. For a normal launch without --output or --reload, Harnest retains the validated compilation under .harnest/artifacts/. A later launch with the same source, configuration, locks, and managed compiler starts from that artifact without importing and validating the graph again. When any of those inputs changes, Harnest publishes a new immutable generation before it removes the superseded generation in the background. Reload after authored file changes during local development:

harnest serve . --reload

URL	Use it for
`http://127.0.0.1:1907/`	Test the agent in the playground
`http://127.0.0.1:1907/docs`	Inspect the generated API
`http://127.0.0.1:1907/healthz`	Check process health

Open the playground

Test managed or advanced ADK and LangGraph agents in the same UI.

Inspect the API

Explore HTTP, SSE, sessions, approvals, and client tools.

Override the bind, limits, timeout, concurrency, or playground under the optional server: section in config.yaml. Omit it to use the defaults.

See development reload for restart behavior and Serving agents for the HTTP, SSE, WebSocket, approval, authentication, storage, and production boundaries.

Overview

Get started

Guides

Serve a project

Open the playground

Inspect the API