Ultrareview is a premium slash command in Claude Code that kicks off a deep, multi-agent code review in a remote sandbox. Instead of a single-pass scan in your terminal, it spins up a fleet of reviewer agents on Claude Code's web infrastructure to hunt for real bugs in a branch or pull request, with each finding independently reproduced before it lands back in your session.
What ultrareview actually does
When you invoke the command, Claude Code bundles your repository state (or, in PR mode, points the sandbox at GitHub directly) and dispatches multiple reviewer agents in parallel. Each agent looks at the diff from a different angle. Before anything is reported, a verification pass tries to reproduce the issue against the real code, so style nitpicks and hallucinated bugs get filtered out.
The tradeoff is time and money. A run takes roughly 5 to 10 minutes and costs about $5 to $20 once you exhaust free runs, which is why it's positioned as a pre-merge check rather than a while-you-type linter.
Requirements and where it won't run
| Requirement | Detail |
|---|---|
| Claude Code version | v2.1.86 or later |
| Authentication | Claude.ai account (API-key-only sessions must run /login first) |
| Extra usage | Must be enabled to run paid reviews; check with /extra-usage |
| PR mode | Repository needs a github.com remote |
| Unsupported | Amazon Bedrock, Google Cloud Vertex AI, Microsoft Foundry, and any org with Zero Data Retention enabled |
If your repo is too large to bundle and upload, Claude Code will prompt you to switch to PR mode. The workaround is to push the branch, open a draft PR, and rerun with the PR number.
Running it from the CLI
Step 1: Open a terminal inside any git repository that Claude Code recognizes, and make sure you're signed in with a Claude.ai account. If you've only authenticated with an API key, run /login first.
Step 2: Run /ultrareview on its own to review the diff between your current branch and the default branch, including uncommitted and staged changes. Pass a PR number (for example, /ultrareview 1234) to have the remote sandbox clone that pull request from GitHub instead.
Step 3: Confirm the scope in the dialog that appears. It shows what's being reviewed, how many free runs you have left, and the estimated cost. Once you accept, the review runs in the background, so you can keep coding, start other commands, or close the terminal.
Tracking and stopping a review
Use /tasks to see running and completed reviews, open the detail view, or stop a review that's still in progress. Stopping archives the cloud session and discards any partial findings, so it's an all-or-nothing call.
When the review finishes, verified findings land as a notification in your session. Each one includes the file and line, plus an explanation you can hand straight back to Claude with a "fix this" follow-up.
Pricing and free runs
| Plan | Free runs | After free runs |
|---|---|---|
| Pro | 3, one-time allotment | Billed as extra usage |
| Max | 3, one-time allotment | Billed as extra usage |
| Team and Enterprise | None | Billed as extra usage |
The three free runs on Pro and Max do not refresh. After that, every run is billed as extra usage, typically $5 to $20 depending on how large the change is. If extra usage isn't enabled on your account or org, Claude Code blocks the launch and links out to billing so you can flip it on.
Ultrareview vs /review
| /review | /ultrareview | |
|---|---|---|
| Where it runs | Locally, in your current session | Remote cloud sandbox |
| Depth | Single-pass review | Multi-agent fleet with independent verification |
| Duration | Seconds to a few minutes | Roughly 5 to 10 minutes |
| Cost | Counts toward normal usage | Free runs, then about $5 to $20 per review as extra usage |
| Best for | Fast feedback while iterating | Pre-merge confidence on substantial changes |
The short version: /review is for the inner loop, /ultrareview is for the gate before you hit merge on something meaningful.
If the command doesn't appear
Ultrareview is a research preview, and availability can lag behind the docs. Some users on recent Claude Code builds, including v2.1.111 on macOS with a Max subscription, have reported that /ultrareview and /ultraplan don't show up in /help or resolve as slash commands. The feature sits behind a feature flag and an entitlement check on the server side, so being on the right version and plan isn't always enough on its own.
If the command isn't visible:
- Confirm you're on Claude Code v2.1.86 or later with
claude --version. - Make sure you're signed in through
/loginwith a Claude.ai account, not just an API key. - Check that your organization doesn't have Zero Data Retention enabled and isn't routing Claude Code through Bedrock, Vertex AI, or Foundry.
- Verify extra usage is on via
/extra-usage, since a disabled billing path can gate paid features.
Rollout is staged, so eligibility can change without a client update.
When to reach for it
Ultrareview earns its cost on substantial, pre-merge changes, such as refactors that touch concurrency, auth, or data handling, long-running feature branches, or PRs where a single-pass review has a decent chance of missing a subtle regression. For a quick sanity check on a small diff, the local /review is faster, cheaper, and usually good enough. Save the multi-agent fleet for the moments where a missed bug would be expensive.