Claude Code version 2.1.147 shipped on May 21 and removed the /simplify command, replacing it with /code-review. Per Claude Code’s official changelog, the new command reports correctness bugs at a chosen effort level (e.g., /code-review high) and accepts a --comment flag that posts findings as inline GitHub pull-request comments. The old cleanup-and-fix behavior of /simplify has been removed; this is not a rename, it is a replacement.

What is gone

/simplify had been Claude Code’s slash command for cleanup and small fixes: invoke it on a file or a diff, get back a modified version with the proposed cleanup applied. The verb was, in practice, “fix.” Version 2.1.147 deletes that verb. The new command does not apply changes. It reports them, at the effort level you specify, and optionally posts the report as a PR comment for a human to act on.

What replaced it

/code-review produces correctness findings rather than edits. The effort level — /code-review high, for example — sets how thoroughly the reviewer reads the code. The --comment flag turns the output into a sequence of inline GitHub PR comments instead of a terminal report; the workflow is “open the PR, run the command, see the comments on the diff.”

What else shipped in 2.1.147

The same release notes report that pinned background sessions (Ctrl+T in claude agents) now stay alive when idle, restart in place to apply Claude Code updates, and are shed under memory pressure only after non-pinned sessions. The pinned-session change is a reliability improvement; the command replacement is a directional one.

Community response

An upstream GitHub issue in the Claude Code repository requests /simplify back. The change has not been reverted; the reframe — AI tools stepping back from auto-fix and into report — is taken up in from fix to report.