Turn Specs Into Apps. Autonomously.

CopilotHarness wraps GitHub Copilot CLI in a persistent loop that plans, implements, verifies, and iterates until your application is complete.

Get Started View on GitHub

async function build()

verifyTests()

git commit -m "feat"

progress.json

The Problem with AI Coding Agents

⚠️

Context Amnesia

Each session forgets what happened before

⚠️

One-Shot Failure

Tries to build everything at once

⚠️

Premature Victory

Declares done when code is half-written

⚠️

Untested Output

Code looks right but doesn't run

How CopilotHarness Fixes This

✅

Perfect Memory

Reads progress.json to resume exactly where it left off

✅

Incremental Success

One feature at a time, fully tested

✅

Definition of Done

Only stops when every checklist item passes

✅

Verified Code

Browser automation confirms features work

The Autonomous Loop

This is how the Harness works

📝

Your Spec

Define what you want to build

⚙️

Initializer

Sets up repo & environment

📋

Feature Checklist

Breaks down into atomic tasks

🤖

Copilot Implements

Writes code & tests

✅

Verify & Test

Runs browser automation

📊

Update Progress

Commits & marks complete

📦

Finished App

Ready for deployment

Built for Reliability

🔒

Security Sandbox

Allowlist of safe commands only

Prevents dangerous operations with command allowlisting. Only git, npm, and safe file operations permitted. Protects your system from untrusted code execution.

🎭

Browser Automation

Playwright MCP for real verification

Uses Playwright to test features like a real user. Clicks buttons, fills forms, and verifies visual appearance - not just API calls.

🔄

Recovery Mode

Auto-simplifies when stuck

Detects when the agent is making no progress and automatically simplifies the task or requests human guidance. Never spins forever.

📊

Progress Tracking

Every session leaves detailed notes

Maintains progress.json with what was accomplished, what broke, and what's next. Each session picks up exactly where the last one left off.

🌿

Git Integration

Creates repo and commits per feature

Initializes git repository automatically and commits after each verified feature. Full audit trail of what was built when.

📋

200+ Test Cases

Comprehensive checklist from your spec

Automatically generates hundreds of test cases from your app specification. Agent works through them one by one until all pass.

See It In Action

copilot-harness — zsh

# Sample app_spec.txt

Build a todo app with React and Express...

➜ ~ |

What Developers Are Saying

Finally, an AI that actually finishes what it starts.

Developer

Software Engineer

The progress tracking is a game changer for complex projects.

Developer

Tech Lead

I defined a spec and had a working app by the next morning.

Developer

Founder

Ready to Build Autonomously?

Get Started on GitHub Read the Documentation

⭐ Star us on GitHub