🌐 Language / 语言
English •
简体中文 •
日本語 •
한국어
cc-harness
Multi-agent harness framework for long-running application development with Claude Code.
Based on Anthropic's research: Harness Design for Long-Running Application Development
Why This Exists
Single-agent approaches to complex coding tasks produce superficially impressive but often broken results. Two persistent problems:
- Self-evaluation bias — Models confidently praise their own mediocre work. Separating creation from evaluation is the strongest lever for quality.
- Context deterioration — Models lose coherence over long sessions. Structured handoffs and context management keep multi-hour builds on track.
This plugin implements a generator-evaluator architecture (inspired by GANs) that drives real quality through iterative feedback loops.
Architecture
User Prompt (1-4 sentences)
│
▼
┌──────────────┐
│ PLANNER │──→ SPEC.md (ambitious product spec)
│ (read-only) │
└──────────────┘
│
▼
┌──────────────┐ file-based ┌──────────────┐
│ GENERATOR │◄──────communication────────►│ EVALUATOR │
│ (builds) │ │ (tests) │
└──────────────┘ └──────────────┘
│ │
git commit tests live app
▲ via Playwright/
└────────iterate if FAIL──────────────browser tools
Quick Start
Installation
# Add the marketplace
/plugin marketplace add Jinsong-Zhou/cc-harness
# Install the plugin
/plugin install cc-harness@cc-harness-marketplace
Then restart Claude Code.
Usage
# Start a harnessed development session
/harness Build a browser-based DAW using the Web Audio API
# Evaluate current work at any point
/evaluate
/evaluate the login flow
/evaluate frontend design
# Check session progress
/harness-status
What's Inside
cc-harness/
├── .claude-plugin/
│ ├── plugin.json # Plugin identity & metadata
│ └── marketplace.json # Marketplace distribution config
│
├── agents/
│ ├── planner.md # Expands prompts → ambitious product specs
│ ├── generator.md # Builds features one at a time, commits to git
│ └── evaluator.md # Skeptical QA — tests live apps, grades against criteria
│
├── skills/
│ ├── harness-loop/
│ │ ├── SKILL.md # Core generator-evaluator iteration loop orchestration
│ │ └── references/
│ │ ├── sprint-contract-examples.md # Worked examples of sprint contracts
│ │ └── evaluation-examples.md # Calibrated QA feedback examples from real runs
│ ├── context-management/
│ │ └── SKILL.md # Compaction vs reset strategies for long sessions
│ └── harness-tuning/
│ ├── SKILL.md # Evaluator calibration & harness simplification
│ └── references/
│ └── audit-template.md # Template for auditing harness component necessity
│
├── commands/
│ ├── harness.md # /harness — start a harnessed development session
│ ├── evaluate.md # /evaluate — trigger standalone QA evaluation
│ └── harness-status.md # /harness-status — show session progress & scores
│
├── rules/
│ └── common/
│ ├── harness-workflow.md # Mandatory pipeline: plan → contract → build → evaluate
│ ├── evaluator-discipline.md # Evaluator mindset rules — skepticism over politeness
│ ├── context-strategy.md # When to compact vs reset, model-specific guidance
│ └── file-communication.md # File-based agent communication protocol
│
├── hooks/
│ └── hooks.json # Lifecycle hooks: SessionStart, PreCompact, Stop
│
├── scripts/
│ └── hooks/
│ ├── run-with-flags.js # Profile-based hook runner (minimal/standard/strict)
│ └── track-iteration.js # Iteration counter, state persistence, session summaries
│
├── examples/
│ └── todo-app-harness/ # Complete worked example of a harness session
│ ├── SPEC.md # Example planner output
Jinsong-Zhou