Skeptic

Your coding agent says it works. Skeptic proves it.

Skeptic is an open-source verification agent for AI-built web applications. Give it a running app and acceptance criteria written in Markdown; it explores the product in a real browser, attempts to disprove each claim, and returns evidence-backed verdicts with replayable Playwright tests.

Each criterion is classified as PASS, FAIL, UNVERIFIABLE, or HARNESS_ERROR.

Requirements

• Node.js 24
• pnpm 10.7

Install

Published npm package:

npm install @pol-cova/skeptic

The package name is reserved. The verification CLI is still under development in this repository.

Clone and install from source:

git clone https://github.com/pol-cova/Skeptic.git
cd Skeptic
pnpm install

Quick start

Run the reference demo app:

pnpm demo:dev

Open http://127.0.0.1:3100/login and sign in with demo / skeptic-demo.

Start the Eve agent:

pnpm dev

Development

pnpm typecheck
pnpm test
pnpm lint
pnpm build

Skeptic uses a local ChatGPT subscription through codex login by default. Set SKEPTIC_PROVIDER to use OpenRouter, Cerebras, Bedrock, or an OpenAI-compatible endpoint. Credentials stay in environment variables; never commit them.

Repository layout:

• packages/ — core, CLI, Playwright harness, and report
• agent/ — Eve verification agent
• examples/demo-app/ — reference application

Further reading:

• Day 0 preflight
• Public contract (ADR 0001)
• Model providers (ADR 0002)
• Demo app

Planned CLI

skeptic verify \
  --url https://preview.example.com \
  --criteria acceptance.md

License

Apache-2.0. See LICENSE.

Community

• Contributing
• Code of Conduct
• Security policy