---

name: golang-language description: Core idioms, style guides, and best practices for writing idiomatic Go code. Use when writing Go code following official style guides and idiomatic patterns. metadata: triggers: files: - 'go.mod' keywords: - golang - go code - idiomatic - gofmt - goimports - iota - golang style

Golang Language Standards

Priority: P0 (CRITICAL)

Guidelines

• Formatting: Run gofmt or goimports on save. Use gopls for LSP features.
• Naming: Use camelCase for internal (unexported) and PascalCase for public (exported) symbols.
• Packages: Use short, lowercase, singular names (e.g., http, user). Avoid _ or camelCase in package names.
• Interfaces: Small interfaces — 1-2 methods max. Define where used (consumer side), not where implemented.
• Errors: Return error as last return value. Handle errors immediately at call-site.
• Slices: Use make(slice, len, cap) to pre-allocate capacity and avoid redundant re-allocations.
• Enums: Use const block with iota for type-safe enumerations.
• Zero Values: Leverage zero-value initialization over explicit nil checks where possible.

Anti-Patterns

• No init: Use constructors (NewService()), not init(). (not init() — it runs implicitly and makes testing harder)
• No Globals: Use DI, not global mutable state.
• No panic: Return errors, don't panic.
• No _ ignored errors: Always check and handle errors.
• No stutter: log.Error, not log.LogError.

Verification Workflow (Mandatory)

After writing or modifying Go code:

1. mcp__ide__getDiagnostics — catch compile errors and gopls type diagnostics immediately
2. go vet ./... — catch common mistakes (printf mismatches, unreachable code, shadowed vars)
3. goimports -w . — fix imports and formatting in one pass

References

• Idioms
• Effective Go Summary