# Craft Guard Clause

> Crafting Guard Clauses. Early returns for preconditions.

- Skill: `attac-t/craft-guard-clause` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add attac-t/craft-guard-clause`
- Raw SKILL.md: https://api.skillmd.com/api/skills/attac-t/craft-guard-clause/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: attac-t (https://skillmd.com/u/attac-t)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/attac-t/craft-guard-clause

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# Skill: Craft Guard Clause

> "Handle the bad cases first. Let the happy path breathe."

## The Standard

1. **Guards at the top**: All precondition checks before any business logic.
2. **One check, one exit**: Each guard handles one condition, then returns or throws.
3. **Flat over nested**: Guards eliminate if/else trees. Main logic lives at outer scope.

## The Anti-Patterns

| ❌ Don't                     | ✅ Do                          | Why                           |
|-----------------------------|-------------------------------|-------------------------------|
| Nested if/else trees        | Guard clauses                 | Readability, maintainability  |
| Check then continue         | Check then exit               | Happy path stays clear        |
| 10+ guards in one method    | Split the method              | Too many guards = too much responsibility |
| Silent return on failure    | Return Result or throw        | Caller needs to know          |

## Real-World Examples

See [examples.md](examples.md).