Promotes type-safe parsing over validation to enforce data invariants at the type level.
Install
mkdir -p .claude/skills/parse-dont-validate && curl -L -o skill.zip "https://agentskills.codes/api/skills/download/16359" && unzip -o skill.zip -d .claude/skills/parse-dont-validate && rm skill.zipInstalls to .claude/skills/parse-dont-validate
Activation
This is the description your AI agent reads to decide when to run this skill — the better it matches your request, the more reliably it fires.
「Parse, don't validate」原則に基づくコードレビューと設計支援。validateパターン（チェックして結果を捨てる） をparseパターン（チェック結果を型で保持）に変換し、型システムで不変式を強制する設計を促進する。 コードレビュー、新規実装、リファクタリング時にvalidation関数の改善が必要な場合に使用。 対象言語: Rust, Haskell, TypeScript, Scala, Java, Go, Python。 トリガー：「バリデーションを改善して」「型で保証したい」「shotgun parsingを直して」 「不正な状態を型で防ぎたい」「Maybeを減らしたい」といった型安全性関連リクエストで起動。Key capabilities
- →Convert validation patterns to parsing patterns
- →Promote designs that enforce invariants with type systems
- →Improve validation functions during code review
- →Refactor existing implementations to use parsing
- →Detect anti-patterns like `validate*()` returning `()`
- →Transform lists into non-empty arrays or maps
How it works
The skill transforms validation functions that discard information into parsing functions that retain information within a type, ensuring type safety.
Inputs & outputs
When to use parse-dont-validate
- →Replacing validation checks with types
- →Preventing shotgun parsing
- →Improving type safety in APIs
About parse-dont-validate
Identifies runtime validation anti-patterns and converts them into parsing functions that return type-checked values, preventing invalid states.
>-
When not to use it
- →When the cost of refactoring for a single `error "impossible"` is too high
- →When compatibility with existing APIs is required
- →In performance-critical hot paths
Limitations
- →Not suitable for single `error "impossible"` cases due to high modification cost
- →Not recommended when existing API compatibility is a concern
- →Avoid in performance-critical hot paths
How it compares
This approach uses the type system to guarantee invariants, unlike manual validation which requires re-checking and does not provide type guarantees.
Compared to similar skills
parse-dont-validate side by side with the closest alternatives in the catalog.
| Skill | Installs | Updated | Safety | Difficulty |
|---|---|---|---|---|
| parse-dont-validate (this skill) | 0 | 5mo | No flags | Intermediate |
| deepwiki-rs | 25 | 9mo | Review | Intermediate |
| tldr-code | 1 | 7mo | Review | Advanced |
| harness-boundary | 0 | 3mo | No flags | Advanced |
Try saying
Example prompts that trigger this skill in your AI assistant.
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