---
title: "Sandboxes for AI code review: build and test every pull request warm"
description: "Promigence gives AI code-review agents a sandbox forked from an already-built snapshot of the repo, so every suggestion can be built and tested before it is posted."
url: "https://www.promigence.ai/for/code-review"
site: "Promigence"
---

# AI code review that checks every pull request on a warm, built repo

Promigence gives an AI code-review agent a sandbox forked from a verified, already-built snapshot of the repository, so it can build, run the tests and check its suggestions on every pull request without paying for a fresh clone and install each time.

**Who this is for:** Companies building AI code-review products, and teams running review agents on their own repositories.

## What breaks today
### Every pull request pays for a fresh build
To check a suggestion, the reviewer needs the code built and the tests runnable. From a cold machine that is a clone, an install and a build on every pull request.

### Suggestions nobody ran
A review comment that was never compiled or tested is a guess, and developers learn to ignore guesses.

### Review traffic arrives in bursts
A busy morning lands dozens of pull requests at once, and a review that queues behind the others arrives after the author has moved on.

## What changes with Promigence
### Fork from the latest built snapshot
Snapshot the default branch with its build. Each pull request forks from it and brings only its own changes.

### Run the checks before you comment
Build and test the suggested change inside the sandbox, so a comment can say whether it passed.

### Many reviews at once
Fork one sandbox per pull request. A burst of reviews starts together instead of waiting in a queue.

## A warm, built repo for every pull request
```bash
# When the default branch moves
promigence snapshot create --image node:22 \
  --setup "git clone https://github.com/your-org/app /work/repo && git -C /work/repo checkout <40-char sha>" \
  --setup "cd /work/repo && corepack enable && pnpm install && pnpm build" \
  --verify "cd /work/repo && pnpm test" --alias app --wait --wait-timeout 10m

# Per pull request: fork, check out the change, test before commenting
promigence fork --snapshot app --count 1 --cap 1
promigence exec --sandbox "$SANDBOX" -- sh -c "cd /work/repo && git fetch origin $PR_REF && git checkout FETCH_HEAD"
promigence exec --sandbox "$SANDBOX" -- sh -c "cd /work/repo && pnpm test"
```