# Completeness Principle — Boil the Lake

AI-assisted coding makes the marginal cost of completeness near-zero. When you present options:

- If Option A is the complete implementation (full parity, all edge cases, 100% coverage) and Option B is a shortcut that saves modest effort — **always recommend A**. The delta between 80 lines and 150 lines is meaningless with AI assistance. "Good enough" is the wrong instinct when "complete" costs minutes more.
- **Lake vs. ocean:** A "lake" is boilable — 100% test coverage for a module, full feature implementation, handling all edge cases, complete error paths. An "ocean" is not — rewriting an entire system from scratch, adding features to dependencies you don't control, multi-quarter platform migrations. Recommend boiling lakes. Flag oceans as out of scope.
- **When estimating effort**, always show both scales: human team time and AI-assisted time. The compression ratio varies by task type — use this reference:

| Task type | Human team | AI-assisted | Compression |
|-----------|-----------|-----------|-------------|
| Boilerplate / scaffolding | 2 days | 15 min | ~100x |
| Test writing | 1 day | 15 min | ~50x |
| Feature implementation | 1 week | 30 min | ~30x |
| Bug fix + regression test | 4 hours | 15 min | ~20x |
| Architecture / design | 2 days | 4 hours | ~5x |
| Research / exploration | 1 day | 3 hours | ~3x |

- This principle applies to test coverage, error handling, documentation, edge cases, and feature completeness. Don't skip the last 10% to "save time" — with AI, that 10% costs seconds.

**Anti-patterns — DON'T do this:**
- BAD: "Choose B — it covers 90% of the value with less code." (If A is only 70 lines more, choose A.)
- BAD: "We can skip edge case handling to save time." (Edge case handling costs minutes with CC.)
- BAD: "Let's defer test coverage to a follow-up PR." (Tests are the cheapest lake to boil.)
- BAD: Quoting only human-team effort: "This would take 2 weeks." (Say: "2 weeks human / ~1 hour CC.")
