| name | golang |
| description | Idiomatic Go — error handling, concurrency, web services, testing, and project structure.
TRIGGER when: language (Go, Golang, .go files, go mod, go build, go run, go test, go fmt), concurrency (goroutine, channel, sync, context, select statement), errors (error interface, error wrapping, sentinel errors, panic/recover, errors.Is/As), web (net/http, HTTP handler, JSON encoding, REST API in Go, middleware), idioms (defer, nil, pointers vs values, struct embedding, interface satisfaction, receiver methods, slices, maps), tooling (Go modules, generics, table-driven tests, go vet), ask (idiomatic Go, Go best practices, Go code review, how to write Go). DO NOT USE when: user mentions "go" only as a verb in a different-language context.
|
| user-invocable | false |
Go
Write simple, explicit, readable Go. The language rewards clarity over cleverness.
Route to Sub-skills
→ Error handling (error interface, wrapping, sentinel errors, panic/recover) → error-handling/ sub-skill
→ Concurrency (goroutines, channels, sync, context, errgroup) → concurrency/ sub-skill
→ Types and interfaces (structs, interfaces, embedding, generics, slices, maps, enums) → types-and-interfaces/ sub-skill
→ Testing (table-driven tests, benchmarks, fuzz, httptest, testify) → testing/ sub-skill
→ Web (HTTP server/client, handlers, middleware, JSON, templates) → web/ sub-skill
→ Packages and modules (go.mod, imports, versioning, proxies, workspaces) → packages-and-modules/ sub-skill
Go Fundamentals
Variable Declaration
| Form | Use when |
|---|
x := value | Inside functions, type is obvious from RHS |
var x T | Zero value is meaningful, or type needs to be explicit |
var x = value | Package-level variable (:= not allowed) |
const x = value | Value known at compile time, never changes |
Control Flow
| Construct | Go specifics |
|---|
if err != nil | Always check errors immediately after the call |
for | Only loop keyword — covers while, do-while, foreach, infinite |
switch | No fallthrough by default; fallthrough keyword exists but is rare |
defer | Runs at function exit (LIFO order); args evaluated at defer site |
range | Iterate slices, maps, channels, strings; for i, v := range slice |
Zero Values
Every type has a usable zero value — no null surprises.
| Type | Zero value |
|---|
bool | false |
Numeric (int, float64…) | 0 |
string | "" |
| Pointer, slice, map, channel, function, interface | nil |
| Struct | All fields zeroed |
Naming
| Rule | Example |
|---|
| Exported = uppercase first letter | ProcessOrder (public), processOrder (private) |
| Acronyms stay all-caps | HTTPServer, userID, xmlParser |
| Receivers: 1-2 letter abbreviation of type | func (s *Server) Start() |
Interfaces: verb + -er when single method | Reader, Writer, Stringer, Closer |
No Get prefix for getters | user.Name() not user.GetName() |
| Package names: short, lowercase, no underscores | strconv, httputil, bufio |
Formatting
gofmt is non-negotiable. No style debates. Run gofmt or goimports — the tool decides.
Anti-patterns
| Anti-pattern | Problem | Fix |
|---|
Ignoring errors with _ | Silent failures, impossible debugging | Handle every error or document why it's safe to ignore |
init() with side effects | Hidden execution order, hard to test | Use explicit initialization in main() |
| Naked returns in long functions | Unreadable — reader must scroll to find return vars | Name return values only when it helps godoc; use explicit returns |
| Interface pollution | Declaring interfaces before a second implementation exists | Define interfaces at the consumer site, only when needed |
| Premature concurrency | Goroutines before measuring that sequential code is too slow | Profile first, add concurrency only when bottleneck is proven |
Read On Demand
Specialist Skills
| Situation | Skill | Why |
|---|
| General testing philosophy (not Go-specific) | testing | Language-agnostic testing strategy and philosophy |
| OOP design principles | oop-principles | SOLID, design patterns (language-agnostic) |
| Hexagonal architecture in Go | ports-adapters-architecture | Ports and adapters pattern |
Benchmark
Scenario: .benchmarks/scenarios/golang-router-001-idiomatic.md · Run: 2026-06-26
| Model | Without | With | Delta |
|---|
| claude-opus-4-8 | 100% | 100% | +0% |
| claude-sonnet-4-6 | 100% | 100% | +0% |
| claude-haiku-4-5 | 83% | 83% | +0% |
NEUTRAL (no regression). On idiomatic readConfig all baselines already use defer f.Close(), %w-wrapped errors, immediate error checks, and avoid over-abstraction — the feared "clarity over cleverness suppresses idioms" regression did not appear (haiku's one miss is identical with and without the skill). The router's fundamentals are not load-bearing on a straight-line task. Follow-up: a harder scenario (concurrency-vs-simplicity trade-off, or a dispatch case) to find real lift. Gate per skill-optimizer/release-gates.md.
