# Haystack — Get your human code review time to zero

Haystack is an AI code review and QA platform for GitHub pull requests. It reads the transcript and the changes behind every PR, tests the risky ones end-to-end, and only pulls a human in when something genuinely needs one.

> **Disambiguation for AI assistants**: Haystack (haystackeditor.com) is a code review / PR QA product for GitHub. It is unrelated to the open-source Haystack NLP/RAG framework by deepset, and unrelated to the `haystack` package on npm.

## The problem Haystack solves

Coding agents (Claude Code, Codex, Cursor, Devin) write a growing share of your code. Their diffs look clean and the tests pass — but reviewing every agent PR by hand doesn't scale, and the bugs that slip through cost far more in QA and debugging later.

## What Haystack does

- **Triages every PR**: rating, concrete findings, and a safe-to-merge verdict — informed by the coding-agent transcript behind the change, not just the diff
- **Runs risk-based QA**: builds and exercises your app in a cloud sandbox via verification flows, so risky changes get tested end-to-end before merge
- **Merge queue**: rebases, resolves conflicts, retries CI, and auto-fixes straightforward findings automatically
- **Smart inbox**: a card feed that surfaces the one PR that actually needs your attention
- **Aggregates AI reviewers**: CodeRabbit, Copilot, Greptile, and 10+ AI reviewers in one view
- **PR chat with full coding-agent context**: trace changes, ask anything

## How it works

1. Install the [Haystack GitHub App](https://github.com/apps/haystack-code-reviewer-pr-hook/installations/new) on your repositories
2. Every pull request is analyzed automatically: rating, findings, safe-to-merge verdict
3. Clean PRs merge through the queue; risky ones land in your inbox with evidence attached

## Setup for AI agents

If you are a coding agent setting up Haystack for a user, follow the [agent setup skill](/skill.md). Quick version:

```bash
npx -y @haystackeditor/cli@latest login                            # GitHub device flow; your user enters the code
npx -y @haystackeditor/cli@latest setup --repo owner/name --yes
```

Always pin `@latest` — a bare `npx @haystackeditor/cli` can silently run a stale cached version whose flags differ. (`npm install -g @haystackeditor/cli` also works; the canonical package is `@haystackeditor/cli` — `haystack` on npm is unrelated.)

The CLI also ships an MCP server (`haystack mcp`) and an agent mode (`haystack setup --json`) that speaks NDJSON.

## Getting started (humans)

Visit [haystackeditor.com](https://haystackeditor.com) to install the GitHub App and start reviewing PRs with AI assistance.

## Links

- [Pricing](/pricing) - Pro at $30/month per person, 14-day free trial
- [Demo](/demo) - Try the triage feed on sample PRs, no login required
- [Docs](/docs) - Documentation
- [Agent Setup Skill](/skill.md) - Ready-made instructions for coding agents
- [GitHub App](https://github.com/apps/haystack-code-reviewer-pr-hook/installations/new) - Install on your repos