Claude Code now has a real code review command

The old /simplify is now /code-review. It's not just a rename. The command now goes far enough to post its findings as comments directly on a GitHub PR.

Claude Code 2.1.147 · /code-review · --comment · May 21–22

01 · Not a rename — a change of job

The first line of the Claude Code 2.1.147 changelog, shipped on May 21, says the /simplify command became /code-review. It looks like a simple rename, but what it actually does has changed.

	Before (`/simplify`, gone)	Now (`/code-review`, first-class command)
Role	Code-simplification helper	Correctness bug review
Target	current code	current diff
Output	in the terminal	down to PR comments
Focus	refactor suggestions	correctness bugs

The key is that the focus moved. Instead of "make it cleaner," it now looks at "does this change have a bug?" Anthropic has said it runs code review on nearly every PR internally.

02 · What landed in this week's batch

Review effort: tunable — low→max selectable
PR posting: --comment — GitHub inline comments
/usage: by category — skill · subagent · MCP
/diff: keyboard — j · k · PgUp scroll

You can pick the review effort, from low to max. Low and medium surface only a few high-confidence flags, while high and max cast a wider net and catch the uncertain stuff too. In the same week, 2.1.149 made /usage break usage down by skills, subagents, plugins, and MCP servers, and let you scroll /diff from the keyboard.

03 · Where it slots into your workflow

/code-review use cases:

Run it locally once before opening a PR — It only looks at the current diff, so it stays focused on what changed.
Use low effort for busy PRs to get just the essentials — Less noise, high-confidence flags only.
Use --comment to put the review on the PR for important changes — Reviewers see it right inside GitHub.
Not a replacement for human review yet — Safer to treat it as a first-pass filter.

04 · The point is that it isn't a separate tool

The most striking part of this change is that code review didn't arrive as a separate tool — it came in as a single CLI command.

Why it matters: It stays inside your terminal workflow — no separate review bot to wire up.
What to watch: How much accuracy actually differs across effort levels is something you'll only learn by using it.

05 · Eddie's take

"The thing is, the review command doesn't just end on your screen — it goes out to the PR. If it were me, I'd wire it into the team pipeline as a first-pass filter first."

— Eddie

If you're already on Claude Code, update and run /code-review first. And if you've got the /simplify shortcut in muscle memory, just remember the name changed.