Repo Scan

repo-scan

Every ecosystem has its own dependency manager, but no tool looks across C++, Android, iOS, and Web to tell you: how much code is actually yours, what's third-party, and what's dead weight.

When to Use

• Taking over a large legacy codebase and need a structural overview
• Before major refactoring — identify what's core, what's duplicate, what's dead
• Auditing third-party dependencies embedded directly in source (not declared in package managers)
• Preparing architecture decision records for monorepo reorganization

Installation

# Clone first so the pinned commit can be reviewed before installation
set -euo pipefail

REPO_SCAN_COMMIT=2742664ebcad1450c208eda0ae45d3c17fad5dd8
REPO_SCAN_INSTALL_DIR="${CLAUDE_CONFIG_DIR:-$HOME/.claude}/skills/repo-scan"
REPO_SCAN_INSTALL_PARENT="$(dirname "$REPO_SCAN_INSTALL_DIR")"
mkdir -p "$REPO_SCAN_INSTALL_PARENT"
REPO_SCAN_TMP="$(mktemp -d "$REPO_SCAN_INSTALL_PARENT/.repo-scan-install.XXXXXX")"
REPO_SCAN_TOKEN="${REPO_SCAN_TMP##*.}"
REPO_SCAN_STAGE="$REPO_SCAN_TMP/stage-$REPO_SCAN_TOKEN"
REPO_SCAN_BACKUP="$REPO_SCAN_TMP/backup-$REPO_SCAN_TOKEN"
REPO_SCAN_LOCK="$REPO_SCAN_INSTALL_PARENT/.repo-scan-install.lock"
REPO_SCAN_KEEP_TMP=0
REPO_SCAN_LOCK_HELD=0
REPO_SCAN_MV_HAS_NO_TARGET=0
cleanup_repo_scan_install() {
  if [ "$REPO_SCAN_KEEP_TMP" -eq 0 ]; then
    rm -rf -- "$REPO_SCAN_TMP"
  fi
  if [ "$REPO_SCAN_LOCK_HELD" -eq 1 ] && ! rmdir -- "$REPO_SCAN_LOCK"; then
    printf 'Could not release installation lock at %s\n' "$REPO_SCAN_LOCK" >&2
  fi
}
trap cleanup_repo_scan_install EXIT
mkdir "$REPO_SCAN_TMP/mv-probe-source"
if mv -T -- "$REPO_SCAN_TMP/mv-probe-source" \
  "$REPO_SCAN_TMP/mv-probe-destination" 2>/dev/null; then
  REPO_SCAN_MV_HAS_NO_TARGET=1
  rmdir "$REPO_SCAN_TMP/mv-probe-destination"
else
  rmdir "$REPO_SCAN_TMP/mv-probe-source"
fi
move_repo_scan_dir() {
  REPO_SCAN_MOVE_SOURCE=$1
  REPO_SCAN_MOVE_DESTINATION=$2
  REPO_SCAN_MOVE_NAME=${REPO_SCAN_MOVE_SOURCE##*/}
  if [ -e "$REPO_SCAN_MOVE_DESTINATION" ] || [ -L "$REPO_SCAN_MOVE_DESTINATION" ]; then
    return 1
  fi
  if [ "$REPO_SCAN_MV_HAS_NO_TARGET" -eq 1 ]; then
    mv -T -- "$REPO_SCAN_MOVE_SOURCE" "$REPO_SCAN_MOVE_DESTINATION"
    return
  fi
  if ! mv -- "$REPO_SCAN_MOVE_SOURCE" "$REPO_SCAN_MOVE_DESTINATION"; then
    return 1
  fi
  if [ -e "$REPO_SCAN_MOVE_DESTINATION/$REPO_SCAN_MOVE_NAME" ] || \
    [ -L "$REPO_SCAN_MOVE_DESTINATION/$REPO_SCAN_MOVE_NAME" ]; then
    if ! mv -- "$REPO_SCAN_MOVE_DESTINATION/$REPO_SCAN_MOVE_NAME" \
      "$REPO_SCAN_MOVE_SOURCE"; then
      REPO_SCAN_KEEP_TMP=1
      printf 'Move conflict recovery failed; staged data remains at %s\n' \
        "$REPO_SCAN_MOVE_DESTINATION/$REPO_SCAN_MOVE_NAME" >&2
    fi
    return 1
  fi
}

git clone --filter=blob:none --no-checkout \
  https://github.com/haibindev/repo-scan.git "$REPO_SCAN_TMP/source"
git -C "$REPO_SCAN_TMP/source" checkout --detach "$REPO_SCAN_COMMIT"
mkdir -p "$REPO_SCAN_STAGE"
git -C "$REPO_SCAN_TMP/source" archive "$REPO_SCAN_COMMIT" | \
  tar -xf - -C "$REPO_SCAN_STAGE"

# Review "$REPO_SCAN_TMP/source" before approving installation.
printf 'Type install to replace %s after reviewing the pinned source: ' \
  "$REPO_SCAN_INSTALL_DIR" >&2
read -r REPO_SCAN_CONFIRM
if [ "$REPO_SCAN_CONFIRM" != install ]; then
  printf 'Installation cancelled.\n' >&2
  exit 1
fi
if ! mkdir -- "$REPO_SCAN_LOCK" 2>/dev/null; then
  printf 'Another repo-scan installation holds the lock at %s\n' \
    "$REPO_SCAN_LOCK" >&2
  exit 1
fi
REPO_SCAN_LOCK_HELD=1

if [ -e "$REPO_SCAN_INSTALL_DIR" ] || [ -L "$REPO_SCAN_INSTALL_DIR" ]; then
  move_repo_scan_dir "$REPO_SCAN_INSTALL_DIR" "$REPO_SCAN_BACKUP"
fi
if ! move_repo_scan_dir "$REPO_SCAN_STAGE" "$REPO_SCAN_INSTALL_DIR"; then
  if [ -e "$REPO_SCAN_BACKUP" ] || [ -L "$REPO_SCAN_BACKUP" ]; then
    if [ -e "$REPO_SCAN_INSTALL_DIR" ] || [ -L "$REPO_SCAN_INSTALL_DIR" ]; then
      REPO_SCAN_KEEP_TMP=1
      printf 'Replacement failed and target was recreated; previous installation preserved at %s\n' \
        "$REPO_SCAN_BACKUP" >&2
    elif ! move_repo_scan_dir "$REPO_SCAN_BACKUP" "$REPO_SCAN_INSTALL_DIR"; then
      REPO_SCAN_KEEP_TMP=1
      printf 'Replacement and rollback failed; previous installation preserved at %s\n' \
        "$REPO_SCAN_BACKUP" >&2
    fi
  fi
  exit 1
fi

Review the source before installing any agent skill.

Installation completes only the bootstrap. Reload your agent harness, then invoke repo-scan again. This ECC pointer installs the external skill but does not run a scan itself.

Core Capabilities

Analysis Depth Levels

How It Works

1. Classify the repo surface: enumerate files, then tag each as project code, embedded third-party code, or build artifact.
2. Detect embedded libraries: inspect directory names, headers, license files, and version markers to identify bundled dependencies and likely versions.
3. Score each module: group files by module or subsystem, then assign one of the four verdicts based on ownership, duplication, and maintenance cost.
4. Highlight structural risks: call out dead-weight artifacts, duplicated wrappers, outdated vendored code, and modules that should be extracted, rebuilt, or deprecated.
5. Produce the report: return a concise summary plus the interactive HTML output with per-module drill-down so the audit can be reviewed asynchronously.

Examples

On a 50,000-file C++ monorepo:

• Found FFmpeg 2.x (2015 vintage) still in production
• Discovered the same SDK wrapper duplicated 3 times
• Identified 636 MB of committed Debug/ipch/obj build artifacts
• Classified: 3 MB project code vs 596 MB third-party

Best Practices

• Start with standard depth for first-time audits
• Use fast for monorepos with 100+ modules to get a quick inventory
• Run deep incrementally on modules flagged for refactoring
• Review the cross-module analysis for duplicate detection across sub-projects

Links

• GitHub Repository