harn-orchestration

Harn orchestration

Use this skill for workflows, triggers, workers, handoffs, parallelism, durable execution, and agent_loop composition.

Pair it with [[harn-agent]] for loop behavior, [[harn-testing]] for deterministic verification, and [[harn-product-quality]] for product projections.

One execution substrate

• Harn owns scheduling, lifecycle, transcript, replay, lineage, and audit.
• A host adapts Harn state into native UI and concrete capabilities.
• Harn Cloud durably runs the same semantics; it does not fork them.
• CLI, TUI, IDE, headless, and cloud should consume one execution contract.
• Do not add a second scheduler, retry engine, or completion model to a host.
• Repair drift at the owner or projection interface.
• Keep provider-specific behavior behind provider adapters.

Workflow design

• Model a workflow around a durable outcome and typed stages.
• Give every stage explicit input, output, failure, and compensation behavior.
• Keep the external interface small; hide composition inside a deep module.
• Use existing stdlib primitives before adding runtime mechanics.
• Keep pure decisions separate from host effects.
• Route effects through harness.*.
• Make idempotency and resume semantics explicit.
• Persist checkpoints before expensive or irreversible stages.

Agent loops

• Use agent_loop as the one agent entry point; use harness.llm.call or harness.llm.completion for one model request and leave interactive input and editor state to the host.
• Build the flat AgentSpec with agent_options or agent_preset; accept its six named component records when a boundary needs only part of the contract.
• Bound iterations, tool duration, concurrency, tokens, and cost.
• Prefer structural progress and lifecycle events over prompt conventions.
• Define completion against observable artifacts or receipts.
• Use deterministic gates before model judges.
• Put resilience in a composable llm_caller.
• Keep a stable session id for durable work.
• Use harness.agent for open, snapshot, fork, compact, inject, and lifecycle operations. Do not add a parallel ambient session API.
• Treat stop, wait, stand-down, and pivot as lifecycle events.
• Return AgentResult and project its producer-owned terminal.kind; hosts do not derive lifecycle state from text or transport stop reasons.