/code-review locally: review your diff before the PR (it's not just the GitHub bot)

TL;DR Run /code-review in any session and Claude reviews your branch's diff (the commits ahead of your upstream plus anything uncommitted): correctness bugs, and on top of that reuse, simplification, and efficiency cleanups. --fix applies the findings to your working tree; --comment posts them inline on the PR. Pass a file, a PR number, or a main...branch range to scope it. Zero GitHub App.

Search "Claude Code code review" and everything points to the same place: the Team/Enterprise GitHub App that comments on your PRs in the cloud. It exists, but it's not the only thing. There's a /code-review that runs in your terminal, in any session, with nothing to install, and reviews your diff before you open the PR. It's the shift-left almost every solo dev misses.

The docs put it plainly: run /code-review in any Claude Code session and it reviews a diff without installing the GitHub App.

> /code-review

Reviewing: 3 commits ahead of origin/main + 2 uncommitted files
  src/auth/session.ts · src/api/rate-limit.ts

🔴 src/auth/session.ts:142   token refresh races with logout
🟡 src/api/rate-limit.ts:33  rate-limit window doesn't reset on failure
🟣 reuse  validateUser duplicates the logic in src/auth/guards.ts

Apply with --fix · post to the PR with --comment

How to use it

1. What it reviews, and which diff it picks

By default it reviews your branch's diff: the commits you're ahead of your upstream by, plus anything uncommitted in the working tree. It looks for correctness bugs and, since v2.1.151, also reuse, simplification, and efficiency cleanups. It's not a style linter; it's a reviewer that understands your code.

2. Scope it with a target

Plain /code-review uses the default diff. Pass something to narrow it:

/code-review src/auth/session.ts      # a single file
/code-review 1234                      # a GitHub PR
/code-review main...my-feature         # the diff that PR would contain

3. --fix and --comment

• --fix: applies the findings to your working tree after the review. You review them like any other change before committing.
• --comment: posts the findings as inline comments on the PR.

4. Raise the bar with effort, or go to the cloud

A low effort returns fewer, higher-confidence findings; high through max give broader coverage and the odd uncertain one. Without an argument, it uses your session's effort. For the deep, agent-fleet review in the cloud, /code-review ultra launches ultrareview and, with --fix, applies its findings when they come back to your session.

Coming from /simplify?

That was this command's name before v2.1.147, when it applied fixes by default. Since v2.1.154, /simplify is a different thing: a cleanup that applies fixes without hunting for bugs. If you scripted /simplify for bug-finding, it's now /code-review --fix.

Reference

Where it fits

• Don't confuse it with Claude reviewing PRs inside GitHub: that lives in the cloud and fires on the PR; this runs in your terminal, before.
• For a big change, the deep review with verification is /ultrareview in the cloud.
• And the earliest layer, as Claude writes, is the security plugin: it chains in-session security → PR review → CI.

Official docs: Review a diff locally

Requirements

• The reuse/simplification/efficiency cleanups land in v2.1.151; the /simplify change, in v2.1.154.