review

Review — standalone diff review

Runs mumei's review engine against an arbitrary diff and reports findings + verdict in the conversation. No .mumei footprint, no commits, no memory writes.

When to use

• The user wants a strong review of the current changes but is NOT driving the feature through /mumei:compose (spec) or /mumei:peruse (plan).
• The user keeps their own spec/SDD and wants mumei's detector + reviewer + gate pipeline on top of it (pass the spec file as the second argument).
• A change too small to plan, where the user still wants the strongest review.

When NOT to use

• An active mumei feature is mid-flight and the user wants its lifecycle review — use /mumei:compose (spec) or /mumei:peruse (plan) instead.
• The user wants findings persisted / phase advanced / archived — this skill is intentionally read-only.

Method

All steps run from the project root in a git repo. The skill never mutates .mumei, never commits, and never writes the ledger or agent memory.

Step 1 — Resolve base ref and diff

source "${CLAUDE_PLUGIN_ROOT}/hooks/_lib/detectors.sh"
source "${CLAUDE_PLUGIN_ROOT}/hooks/_lib/detectors-ext.sh"
source "${CLAUDE_PLUGIN_ROOT}/hooks/_lib/review.sh"
source "${CLAUDE_PLUGIN_ROOT}/hooks/_lib/residual.sh"

base_arg="$1"   # optional
spec_arg="$2"   # optional spec file for spec-compliance scope_source

if ! git rev-parse --git-dir >/dev/null 2>&1; then
  echo "not a git repository; /mumei:review needs a git repo." >&2
  exit 0
fi

# Base resolution: explicit arg → origin/HEAD → main → master.
if [[ -n "$base_arg" ]]; then
  base="$base_arg"
else
  base="$(git symbolic-ref --quiet --short refs/remotes/origin/HEAD 2>/dev/null \
    | sed 's#^origin/##')"
  [[ -z "$base" ]] && { git show-ref --verify --quiet refs/heads/main && base="main"; }
  [[ -z "$base" ]] && { git show-ref --verify --quiet refs/heads/master && base="master"; }
fi
if [[ -z "$base" ]]; then
  echo "could not resolve a base ref (no origin/HEAD, main, or master). Pass one explicitly: /mumei:review <base-ref>" >&2
  exit 0
fi

merge_base="$(git merge-base "$base" HEAD 2>/dev/null)"
if [[ -z "$merge_base" ]]; then
  echo "could not compute merge-base against '${base}'." >&2
  exit 0
fi

# Includes pushed commits since the branch point AND uncommitted working-tree
# changes (REQ-27.4).
diff="$(git diff "$merge_base")"
diff_lines="$(printf '%s\n' "$diff" | wc -l | tr -d ' ')"
if [[ -z "$diff" ]]; then
  echo "no changes against ${base} (merge-base ${merge_base}); nothing to review."
  exit 0
fi