edge-case-finderlisted

# Edge Case Finder Find edge cases in: **$ARGUMENTS** (scope defaults to all) ## Steps 1. **Read the code** — understand the function/module's purpose, inputs, outputs, and dependencies. 2. **Analyze input boundaries**: - Empty/null/undefined inputs - Single-element collections - Maximum-length strings, arrays at capacity - Negative numbers, zero, MAX_SAFE_INTEGER - Unicode, emoji, RTL text, zero-width characters - SQL injection strings, XSS payloads, path traversal - Extremely long inputs (DoS potential) 3. **Analyze state transitions**: - Initial state (first-time use, empty database) - Race conditions (concurrent calls to the same resource) - State after error (is cleanup handled? partial writes?) - Stale state (cached data that's been updated elsewhere) - State overflow (counters wrapping, queues full) 4. **Analyze external dependencies**: - Network timeout/failure during operation - Database connection pool exhaustion - Partial response from external API - Clock skew (timezone, DST, leap seconds) - File system full, permission denied 5. **Analyze business logic boundaries**: - Off-by-one in pagination, date ranges, loops - Timezone handling (UTC vs local, DST boundaries) - Currency rounding (0.005 → 0.00 or 0.01?) - Locale differences (decimal separator, date format) - Permission boundaries (user A accessing user B's data) 6. **Prioritize by impact**: - **Critical**: data corruption, security vu