Agent Harness Skill

Automates the long-running agent workflow from Anthropic's engineering blog. Manages feature lists, progress tracking, and session orchestration across multiple Claude Code sessions.

Commands

/harness-init <project-description>

Initialize a new project with:

• feature_list.json — comprehensive feature tracking
• claude-progress.txt — cross-session progress log
• init.sh — development server startup script
• .harness.json — harness configuration

/harness-run

Start a coding session. Reads progress, picks the next feature, and follows the incremental development workflow.

/harness-status

Show current project progress: features completed, next features to implement, recent session history.

/harness-feature <description>

Add a new feature to the feature list.

/harness-commit

Commit current work with structured message and update progress file.

Architecture

┌─────────────┐     ┌──────────────┐     ┌──────────────┐
│  Initializer │────▶│  Coding Agent│────▶│   Next Coding│
│    Agent     │     │  Session #1  │     │    Agent #2  │
└─────────────┘     └──────────────┘     └──────────────┘
      │                    │                     │
      ▼                    ▼                     ▼
┌─────────────────────────────────────────────────────────┐
│                    Shared State                          │
│  ┌───────────────┐ ┌──────────────┐ ┌────────────────┐ │
│  │feature_list   │ │claude-progress│ │   Git History  │ │
│  │    .json      │ │    .txt       │ │   (commits)    │ │
│  └───────────────┘ └──────────────┘ └────────────────┘ │
└─────────────────────────────────────────────────────────┘

Workflow

1. Init: harness init "Build a chat app" — sets up project skeleton
2. Code: harness run — each session picks ONE feature
3. Track: Features marked passing only after end-to-end testing
4. Commit: Progress documented in git + progress file
5. Repeat: Continue until all features pass

Key Principles

• Incremental: One feature per session
• Tested: End-to-end testing before marking complete
• Clean state: Always leave codebase merge-ready
• Persistent state: Git + progress file bridge context windows