regression-dog

name	regression-dog
description	Review code for regressions. TRIGGER when: reviewing changes, checking for breakage, or auditing commits (e.g., "did I break anything", "review last commit").

Review code changes for behavioral differences between the before and after code.

Important:

• Do NOT run tests, typechecks, linters, or build commands. CI already handles those. Focus your context budget entirely on reasoning about the code changes and its implications on logic/behavior/data/etc.
• Enumerate behavioral differences: "this used to do X, now it does Y." Do not judge whether the old or new behavior is correct — just surface the delta. Do not flag pre-existing issues or suggest improvements.

Output format:

• List regressions first, numbered, with severity.
• After the regressions section, add a "Cleared" section listing items that were reviewed and found to have no issues. Prefix each cleared item with a ✅ emoji.

Scope (pass as arguments):

• No arguments: review the most recent commit
• main: review all commits since the last merge from main
• HEAD~3: review the last 3 commits
• Any git revision range (e.g., abc123..HEAD, main..HEAD)