@harness-engineering/orchestrator

Orchestrator daemon for dispatching coding agents to issues. Polls an issue tracker for candidate tasks, manages ephemeral workspaces, runs agents to resolve issues, and updates the tracker with progress.

Architecture

┌──────────────────────────────────────────────────┐
│                 Issue Tracker                     │
│  RoadmapTrackerAdapter · Linear Extension        │
└──────────────────┬───────────────────────────────┘
                   ▼
┌──────────────────────────────────────────────────┐
│              Core State Machine                   │
│  Candidate Selection · Concurrency Control       │
│  Reconciliation · Retry Logic                    │
│  Event Sourcing (applyEvent → side effects)      │
└──────────────────┬───────────────────────────────┘
                   ▼
┌────────────────┐  ┌─────────────────┐
│  Agent Runner  │  │   Workspaces    │
│  Claude Backend│  │  WorkspaceManager│
│  Mock Backend  │  │  WorkspaceHooks │
└───────┬────────┘  └────────┬────────┘
        └────────┬───────────┘
                 ▼
┌──────────────────────────────────────────────────┐
│            Prompt Rendering (LiquidJS)           │
└──────────────────────────────────────────────────┘

Quick Start

import {
  Orchestrator,
  loadWorkflowConfig,
  WorkspaceManager,
  WorkspaceHooks,
  ClaudeBackend,
  PromptRenderer,
  RoadmapTrackerAdapter,
} from '@harness-engineering/orchestrator';

// Load workflow configuration
const config = loadWorkflowConfig('./workflow.yaml');

// Create and start the orchestrator
const orchestrator = new Orchestrator(config);
await orchestrator.start();

Core Concepts

Event-Sourced State Machine

The orchestrator uses an event-sourced architecture. All state transitions are modeled as events (OrchestratorEvent) that produce side effects (SideEffect):

import { applyEvent, createEmptyState } from '@harness-engineering/orchestrator';

const state = createEmptyState();
const { state: next, effects } = applyEvent(state, event);
// effects: DispatchEffect, StopEffect, ScheduleRetryEffect, etc.

Candidate Selection

Issues are ranked and filtered before dispatch:

import { sortCandidates, selectCandidates, isEligible } from '@harness-engineering/orchestrator';

const ranked = sortCandidates(issues);
const selected = selectCandidates(ranked, availableSlots);

Agent Backends

Two backends are available:

• ClaudeBackend — Production backend using the Claude API
• MockBackend — Test backend for deterministic behavior in tests

Workspace Management

Each agent run gets an ephemeral workspace with lifecycle hooks:

import { WorkspaceManager, WorkspaceHooks } from '@harness-engineering/orchestrator';

const manager = new WorkspaceManager(config);
const hooks = new WorkspaceHooks(config);

API

Orchestrator

The main class that ties everything together:

• start() — Begin polling and dispatching
• stop() — Gracefully shut down
• Events: state_change, agent_event

Core Functions

| Export | Description | | --------------------- | ----------------------------------------------------------- | | applyEvent | Apply an event to state, returning new state + side effects | | createEmptyState | Create an initial empty orchestrator state | | sortCandidates | Rank issues by priority and eligibility | | selectCandidates | Select top candidates within concurrency limits | | isEligible | Check if an issue is eligible for dispatch | | getAvailableSlots | Get number of available agent slots | | canDispatch | Check if dispatch is possible given current state | | reconcile | Reconcile expected state against actual state | | calculateRetryDelay | Compute exponential backoff delay |

Tracker Adapters

| Export | Description | | ------------------------ | ---------------------------------------- | | RoadmapTrackerAdapter | Reads issues from docs/roadmap.md | | LinearTrackerExtension | Extends tracking with Linear integration |

Prompt Rendering

| Export | Description | | ---------------- | -------------------------------------------- | | PromptRenderer | Renders LiquidJS templates for agent prompts |

License

MIT