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
Initialize a new project with:
feature_list.json— comprehensive feature trackingclaude-progress.txt— cross-session progress loginit.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
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
- Init:
harness init "Build a chat app"— sets up project skeleton - Code:
harness run— each session picks ONE feature - Track: Features marked passing only after end-to-end testing
- Commit: Progress documented in git + progress file
- 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