Pre-release Harn is pre-1.0 — the language, standard library, and CLI may change between releases. See the release notes

Common tasks

Find the task that matches your next step. Follow one path until you have a working first version, then return to the reference pages for detail.

Build an agent#

TaskStart here
Learn the languageLanguage basics
Call a modelLLM calls and agents
Give an agent toolsLLM tools
Add several dependent stagesWorkflow runtime
Run independent child agentsDelegated workers
Test without an API keyMock LLM responses

Connect a system#

TaskStart here
Call an MCP serverMCP, ACP, and A2A integration
Expose a Harn programOutbound workflow server
Receive eventsTrigger manifests
Author a connector packageConnector authoring
Add human approvalHuman in the loop

Operate a run#

TaskStart here
Inspect a runHarn portal
Debug a failed agentDebugging agent runs
Replay or evaluate behaviorTesting
Deploy an orchestratorOrchestrator
Manage secrets and OAuthOrchestrator secrets

Starting from zero#

  1. Follow Getting started.
  2. Read Language basics.
  3. Build one small model-backed program with LLM calls and agents.
  4. Add tools, workflows, or workers only when the task needs them.
  5. Read Best practices before you run unattended or write to an external system.