Install
npx skillscat add eltmon/overdeck/code-review-performance Install via the SkillsCat registry.
SKILL.md
Performance Review
Algorithm Complexity
- Identify O(n^2) or worse algorithms
- Look for unnecessary iterations
- Check for opportunities to use better data structures
Database/API Patterns
- N+1 query detection
- Missing indexes (check query patterns)
- Unbounded queries (missing LIMIT)
- Connection pool exhaustion risks
Memory & Resources
- Memory leaks (unclosed resources)
- Unbounded caches or buffers
- Large object allocations in loops
Concurrency
- Lock contention hotspots
- Blocking operations in async contexts
- Thread pool exhaustion
Blocking Operations (CRITICAL for Node.js)
- execSync/spawnSync - These BLOCK the event loop and cause UI freezes
- Search for:
execSync,spawnSync,readFileSyncin hot paths - ALWAYS flag as HIGH IMPACT - causes perceived hangs and latency spikes
Fix pattern to recommend:
// Replace execSync with async version
import { exec } from 'child_process';
import { promisify } from 'util';
const execAsync = promisify(exec);
const { stdout } = await execAsync('command here');Common offenders in this codebase:
tmux capture-pane/tmux send-keys/tmux has-sessiongit branch/git status/git log
Output Format
For each finding:
- Impact: High/Medium/Low
- Scale factor: "At 10x load, this will..."
- Location: file:line
- Suggested optimization