---

name: sem-integration description: | Provides sem semantic-diff detection, install-on-first-use, and fallback patterns version: 1.9.8 triggers:

• sem
• semantic-diff
• git
• foundation
• building skills that consume git diff output metadata: {"openclaw": {"homepage": "https://github.com/athola/claude-night-market/tree/master/plugins/leyline", "emoji": "\ud83e\udd9e"}} source: claude-night-market source_plugin: leyline

---

Night Market Skill — ported from claude-night-market/leyline. For the full experience with agents, hooks, and commands, install the Claude Code plugin.

sem Integration

Foundation patterns for using sem semantic diffs in night-market skills.

When To Use

Consult this skill when building or modifying skills that consume git diff output. It provides the detection, installation, and fallback patterns.

When NOT To Use

• Direct sem CLI usage (just run sem diff yourself)
• Skills that don't consume diff output

Detection Pattern

Check sem availability once per session:

# Detection (cache per session)
_sem_check() {
  local cache="${CLAUDE_CODE_TMPDIR:-/tmp}/sem-available"
  if [ -f "$cache" ]; then
    cat "$cache"
    return
  fi
  if command -v sem &>/dev/null; then
    echo "1" | tee "$cache"
  else
    echo "0" | tee "$cache"
  fi
}

When _sem_check returns 0, offer installation. See modules/detection.md for install-on-first-use logic and platform-specific commands.

Semantic Diff Pattern

Primary path (sem available):

sem diff --format json <baseline>

Fallback path (sem unavailable):

git diff --name-only --diff-filter=A <baseline>
git diff --name-only --diff-filter=M <baseline>
git diff --name-only --diff-filter=D <baseline>
git diff --name-only --diff-filter=R <baseline>

See modules/fallback.md for output normalization that produces the same entity schema from both paths.

Impact Analysis Pattern

Primary path (sem available):

sem impact --json <file-or-entity>

Fallback path (sem unavailable): use rg/grep to trace callers by filename. See modules/fallback.md.