Golang Structs Interfaces

What it does

When your agent uses it

• Designing Go types
• Implementing interfaces
• Embedding structs
• Writing type assertions

Example prompts

• “accept interfaces, return structs”
• “/golang-structs-interfaces”

Requirements

• Compatibility (from SKILL.md): Designed for Claude Code, Codex or similar harness, and for projects using Golang.
• Pre-approved tools (allowed-tools): Read, Edit, Write, Glob, Grep, Bash(go:*), Bash(golangci-lint:*), Bash(git:*), Agent, AskUserQuestion

What it can do on your machine

Read from SKILL.md and the folder at commit 44923f3. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • Read
  • Edit
  • Write
  • Glob
  • Grep
  • Bash(go:*)
  • Bash(golangci-lint:*)
  • Bash(git:*)
  • Agent
  • AskUserQuestion

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Shell commands in SKILL.md call:

  • go

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

• Compatibility

  Designed for Claude Code, Codex or similar harness, and for projects using Golang.

  From compatibility in the SKILL.md frontmatter.

Context cost

Golang Structs Interfaces loads about 3k tokens when it runs, and up to ~4.5k if it reads all its reference files. Until then it costs about 162 tokens; SKILL.md has 1,057 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~162

When it runs · the whole SKILL.md, loaded when a task matches

~3k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~4.5k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from aiskillstore/marketplace at commit 44923f3, republished under its MIT licence (© aiskillstore). 1,057 words, ~3,025 tokens.

name

golang-structs-interfaces

description

Golang struct and interface design patterns — composition, embedding, type assertions, type switches, interface segregation, dependency injection via interfaces, struct field tags, and pointer vs value receivers. Use this skill when designing Go types, defining or implementing interfaces, embedding structs or interfaces, writing type assertions or type switches, adding struct field tags for JSON/YAML/DB serialization, or choosing between pointer and value receivers. Also use when the user asks about "accept interfaces, return structs", compile-time interface checks, or composing small interfaces into larger ones.

allowed-tools

Read, Edit, Write, Glob, Grep, Bash(go:*), Bash(golangci-lint:*), Bash(git:*), Agent, AskUserQuestion

compatibility

Designed for Claude Code, Codex or similar harness, and for projects using Golang.

user-invocable

true

license

MIT

metadata.author

samber

metadata.version

1.2.1

paths

**/*.go

type Reader interface {
    Read(p []byte) (n int, err error)
}

type Writer interface {
    Write(p []byte) (n int, err error)
}

// Composed from small interfaces
type ReadWriter interface {
    Reader
    Writer
}

type ReadWriteCloser interface {
    io.Reader
    io.Writer
    io.Closer
}

// package notification — defines only what it needs
type Sender interface {
    Send(to, body string) error
}

type Service struct {
    sender Sender
}

// Good — accepts interface, returns concrete
func NewService(store UserStore) *Service { ... }

// Bad — an interface return hides every other method of the concrete type from callers
func NewService(store UserStore) ServiceInterface { ... }

// Bad — premature interface with a single implementation
type UserRepository interface {
    FindByID(ctx context.Context, id string) (*User, error)
}
type userRepository struct { db *sql.DB }

// Good — start concrete, extract an interface later when needed
type UserRepository struct { db *sql.DB }

// Good — zero value is ready to use
var buf bytes.Buffer
buf.WriteString("hello")

var mu sync.Mutex
mu.Lock()

// Bad — zero value is broken, requires constructor
type Registry struct {
    items map[string]Item // nil map, panics on write
}

// Good — lazy initialization guards the zero value
func (r *Registry) Register(name string, item Item) {
    if r.items == nil {
        r.items = make(map[string]Item)
    }
    r.items[name] = item
}

// Bad — loses type safety
func Contains(slice []any, target any) bool { ... }

// Good — generic, type-safe
func Contains[T comparable](slice []T, target T) bool { ... }

var _ io.ReadWriter = (*MyBuffer)(nil)

type Logger struct {
    *slog.Logger
}

type Server struct {
    Logger
    addr string
}

// s.Info(...) works — promoted from slog.Logger through Logger
s := Server{Logger: Logger{slog.Default()}, addr: ":8080"}
s.Info("starting", "addr", s.addr)

// Embed — Server exposes all http.Handler methods
type Server struct {
    http.Handler
}

// Named field — Server uses the store but doesn't expose its methods
type Server struct {
    store *DataStore
}

type UserStore interface {
    FindByID(ctx context.Context, id string) (*User, error)
}

type UserService struct {
    store UserStore
}

func NewUserService(store UserStore) *UserService {
    return &UserService{store: store}
}

type Order struct {
    ID        string    `json:"id"         db:"id"`
    Total     float64   `json:"total"      db:"total"`
    CreatedAt time.Time `json:"created_at" db:"created_at"`
    Internal  string    `json:"-"          db:"-"`
}

© aiskillstore, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 4 other files (references) in skills/samber/golang-structs-interfaces of aiskillstore/marketplace.

• SKILL.md
• evals/evals.json
• references/struct-fields.md
• references/type-assertions.md
• skill-report.json

Open the folder on GitHubat commit 44923f3

Used in 1 other repository

We found 1 copy of this SKILL.md (exact, near-identical or edited) in other folders, from 1 other GitHub owner. This page covers the copy in aiskillstore/marketplace, which our catalogue first saw on October 7, 2026.

• samber/cc-skills-golangskills/golang-structs-interfaces