Fabric Harness in 5 minutes

Fabric Harness starts with one TypeScript definition: call init(), open a session, and prompt it. The default path uses the lightweight virtual sandbox, so you do not need Docker, Temporal, Cloudflare, or a remote sandbox to start.

Create an agent

npx @fabric-harness/cli init my-agent --template minimal
cd my-agent
npm install

Validate readiness

npx fabric-harness doctor --getting-started --tools

This checks Node, ESM package setup, Fabric dependencies, agent discovery, session storage, model resolution, and built-in tool schemas.

Run it

npx fabric-harness agents
npx fabric-harness run hello --name Preetham --mock

Or start the HTTP/SSE dev server:

npx fabric-harness dev --mock
curl http://localhost:3000/jobs/hello \
  -H 'content-type: application/json' \
  -d '{"name":"Preetham"}'

The mock provider requires no API key and still exercises discovery, schema validation, the model loop, and HTTP routing. Remove --mock after configuring a real provider.

Create more definitions without writing boilerplate:

fh new job summarize-report
fh new agent support

Choose the next runtime

Start with the minimal template, then add only the enterprise controls your use case needs: policy, approvals, audit, cost budgets, durable workflows, and deployment attestations.