# Tdd · max4c

> Test-driven development with red-green-refactor discipline and vertical-slice tracer bullets. Use this skill whenever the user is building or fixing code in testable layers — parsers, formatters, services, pure functions, data models, CLI commands — even if they don't explicitly say "TDD". Triggers include "add a feature to the parser", "fix a bug in the formatter", "implement this utility", "write tests for X", "test-driven", "red-green-refactor", or any time the user is about to write logic that has a clean public interface. Skip for SwiftUI views, animations, visual polish, and system-framework integrations (EventKit, Core Data) where smoke tests and computer-use verification are more honest — the skill body has a "when NOT to TDD" section explaining the boundary. Use max:verify-before-done for the non-testable cases.

## Facts
- Page: https://tashan.sh/capability/skill-max4c-tdd
- tashan id: skill:max4c/tdd
- Source: https://github.com/max4c/skills
- Type: skill
- Category: other
- tashan score: 34.0 / 100
- Adoption: 14.0
- Upkeep: 54.0
- Freshness: 78.0
- Evidence coverage: 84% of the inputs this score can use
- Health: active
- Instruction depth: not yet graded
- License: MIT
- Official: no

## Install

```sh
cp -r tdd ~/.claude/skills/
```

## Security audit
Not scanned. We audit npm-published capabilities; this one has no npm package we can resolve, or has not reached the queue. This is not a clean bill of health.

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Measured 2026-08-15 by tashan (https://tashan.sh) from public evidence. Scorer s5.