swift-error-handling
Standards for throwing functions, Result type, and Never. Use when implementing Swift error throwing, designing error hierarchies, using Result types, or adding do-catch blocks. (triggers: **/*.swift, throws, try, catch, Result, Error)
Best use case
swift-error-handling is best used when you need a repeatable AI agent workflow instead of a one-off prompt.
Standards for throwing functions, Result type, and Never. Use when implementing Swift error throwing, designing error hierarchies, using Result types, or adding do-catch blocks. (triggers: **/*.swift, throws, try, catch, Result, Error)
Teams using swift-error-handling should expect a more consistent output, faster repeated execution, less prompt rewriting.
When to use this skill
- You want a reusable workflow that can be run more than once with consistent structure.
When not to use this skill
- You only need a quick one-off answer and do not need a reusable workflow.
- You cannot install or maintain the underlying files, dependencies, or repository context.
Installation
Claude Code / Cursor / Codex
Manual Installation
- Download SKILL.md from GitHub
- Place it in
.claude/skills/swift-error-handling/SKILL.mdinside your project - Restart your AI agent — it will auto-discover the skill
How swift-error-handling Compares
| Feature / Agent | swift-error-handling | Standard Approach |
|---|---|---|
| Platform Support | Not specified | Limited / Varies |
| Context Awareness | High | Baseline |
| Installation Complexity | Unknown | N/A |
Frequently Asked Questions
What does this skill do?
Standards for throwing functions, Result type, and Never. Use when implementing Swift error throwing, designing error hierarchies, using Result types, or adding do-catch blocks. (triggers: **/*.swift, throws, try, catch, Result, Error)
Where can I find the source code?
You can find the source code on GitHub using the link provided at the top of the page.
SKILL.md Source
# Swift Error Handling ## **Priority: P0** ## Workflow: Add Error Handling to a Swift Function 1. Define a custom error enum conforming to `Error` 2. Mark the function `throws` (or `async throws`) 3. Use `do-catch` at the call site with specific catch clauses 4. Map domain errors to user-facing messages at the presentation layer ## Implementation Guidelines ### Throwing Functions - **Propagate Errors**: Use `throws` for recoverable errors and `async throws` for modern concurrency. - **Do-Catch**: Handle errors close to source with specific catch clauses for each error type. Catch-all `catch` should be the last resort. - **Error Types**: Define custom errors as enums conforming to `Error`: See [implementation examples](references/implementation.md) for custom error enums, do-catch patterns, and Result type usage. - **Optional Try**: Use `try?` only for non-critical errors where nil is acceptable. ### Result Type - **Async Alternatives**: Use `throws` for synchronous code. Use `Result` for callbacks and non-async deferred error states. - **Transformations**: Use `.map()`, `.flatMap()` for functional composition. - **Conversion**: Use `.get()` to convert `Result` to throwing for use in `try-catch`. ### Never Type & Preconditions - **Fatalisms**: Use `Never` return type only for unrecoverable crash scenarios or to indicate unreachable code. Never for expected errors. - **Preconditions**: Use `precondition()`, `assert()`, and `fatalError()` for programmer errors. Use `assertionFailure()` for debug-only checks. ## Anti-Patterns - **No try!**: Use `try?` or `do-catch`. - **No try? without nil check**: Handle or log. - **No Error(message)**: Use typed errors. ## References - [Error Types & Result](references/implementation.md)
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