AI code review for GitHub pull requests

Know what happened
before you merge.

Connect GitHub to one repository. Zeus reviews a pull request in an isolated sandbox, runs a targeted check when a claim needs proof, and posts merge advice and findings back to GitHub.

Start free with GitHub See how it works

Next: connect one repository, then review your first PR.

Repository-scoped access. Isolated sandbox. See access details.

example review output runtime-backed finding
✓Finding with runtime proof
Zeus found a second refund path.↗
Built for the pull requestRuns the code when it helpsPosts the result to GitHub

01The review gap

AI wrote the change.
Read the diff.
Test the claim.

Most review tools inspect the patch and make a claim. Zeus can inspect the patch, run a targeted check, and give you the observed result. That changes the question from "does this look safe?" to "what happened when we tested it?"

Review a pull request
01

Find the defect

Zeus reads the change and checks the code paths that the pull request touches.

02

Run the claim

When static reasoning is not enough, Zeus uses the checked out repo and shell.

03

Show the result

Runtime-backed findings include the test, what happened, and a short explanation.

02How it works

From pull request
to merge advice.

Connect GitHub once. Zeus works where your team already reviews code.

01

Connect a repository

Install Arcanist on the repository you want to review. Start a review from a PR comment or let it run when a PR opens.

@tryarcanist /review
02

Zeus checks the change

It gets the repo, dependencies, and shell in an isolated sandbox. When a claim needs proof, it runs a targeted check.

14 files · 3 paths · 1 probe
03

Your PR gets an answer

Zeus posts merge advice and findings to GitHub. Blocking issues, follow-ups, and clean reviews stay easy to tell apart.

✓ merge with follow-ups

03What the result looks like

A finding you
can check.

Zeus keeps the merge decision short and puts runtime evidence beside the finding when it has it. You can see what it tested, what happened, and what to change without translating a confidence score.

  • ✓ Blocking findings lead the review.
  • ✓ Follow-ups stay separate from merge advice.
  • ✓ Clean reviews say merge.
zeus reviewcompleted
acme / checkoutpull request #184
✓Merge with follow-ups
01

Blocking finding

Refund can be issued twice

A retry after the payment provider times out does not re-check the stored refund id.

reproduced with a failing probe
02

Follow-up

Add coverage for the retry path

evidence attachedposted to GitHub

04Pricing

Try it on your
own repository.

Starter is free for one PR author and includes 10 successfully published reviews each month. Teams can add authors and pay monthly.

Start freeNo card required
$0Starter
Team$25per active author / month

25 successful reviews per author included, then $1 per additional review.

Start free with GitHub

Connect one repository and review your first PR.

05Questions

Before you
connect GitHub.

Here is the short version of what Zeus does and how it fits with the tools you already use.

What does Zeus review?

Zeus reviews pull requests and gives merge advice from the findings it publishes. A clean review means it found no publishable findings. Findings that block a merge are separated from follow-up work.

How is this different from a review bot that reads the diff?

Zeus starts with the diff, then uses the checked-out repository, installed dependencies, and shell when a claim needs proof. It can run a decisive probe, reproduce a defect, and include the steps and observed result in the finding.

Will Zeus replace CI?

No. CI owns your suite status. Zeus looks for novel defects and uses runtime evidence when it helps prove a finding. A red CI check by itself does not change Zeus merge advice.

What does it cost?

New teams start with 50 free reviews while the repository environment is tuned. After that, reviews are $0.50 each. You can also request a team conversation if you need a different setup.

What access does Zeus need?

You connect a GitHub repository through Arcanist. Review sessions run with repository-scoped access in an isolated sandbox. The app handles authorization and token use on the server.

Can Zeus block a merge?

Zeus is advisory by default. Its GitHub check can be configured to block merges for a repository. A clean review means Zeus found no publishable findings. It does not replace CI or guarantee that a change is safe.

What happens after I connect GitHub?

You choose a repository, then Reviews suggests an open pull request. Start the review there, or use the PR comment command when you want to review a different change. Zeus checks out the branch and posts the result back to GitHub.

Make the next merge
easier to trust.

Connect a repository and let Zeus review the next pull request.

Start free with GitHub Talk to the team