Go Concurrency

What it does

When your agent uses it

• Writing concurrent Go code — goroutines
• Thread-safety guarantees
• Parallelizing work
• Fixing data races

Example prompts

• “/go-concurrency”

Workflow steps

4 steps, taken from the first numbered list in SKILL.md.

1. 1Every goroutine needs a stop mechanism — a predictable end time, a
2. 2Code must be able to wait for the goroutine to finish
3. 3No goroutines in init() — expose lifecycle methods (Close, Stop,
4. 4Keep synchronization scoped — constrain to function scope, factor logic

What it can do on your machine

Read from SKILL.md and the folder at commit 91f0c2e. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are go).

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

• Network

  Links to these hosts (documentation or services it may open):

  • pkg.go.dev
  • dave.cheney.net
  • youtube.com
  • changelog.com

  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.

Context cost

Go Concurrency loads about 1.8k tokens when it runs, and up to ~4.6k if it reads all its reference files. Until then it costs about 80 tokens; SKILL.md has 664 words of instructions outside code blocks.

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

~80

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

~1.8k

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

~4.6k

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 cxuu/golang-skills at commit 91f0c2e, republished under its Apache-2.0 licence (© cxuu). 664 words, ~1,775 tokens.

name

go-concurrency

description

Use when writing concurrent Go code — goroutines, channels, mutexes, or thread-safety guarantees. Also use when parallelizing work, fixing data races, or protecting shared state, even if the user doesn't explicitly mention concurrency primitives. Does not cover context.Context patterns (see go-context).

// Good: Clear lifetime with WaitGroup.Go (Go 1.25+)
var wg sync.WaitGroup
for item := range queue {
    item := item
    wg.Go(func() { process(ctx, item) })
}
wg.Wait()

// Bad: No way to stop or wait
go func() { for { flush(); time.Sleep(delay) } }()

// Good: Zero-value is valid    // Bad: Unnecessary pointer
var mu sync.Mutex                mu := new(sync.Mutex)

func produce(out chan<- int) { /* send-only */ }
func consume(in <-chan int)  { /* receive-only */ }
func transform(in <-chan int, out chan<- int) { /* both */ }

c := make(chan int)    // unbuffered — Good
c := make(chan int, 1) // size one — Good
c := make(chan int, 64) // arbitrary — needs justification

// Good: Type-safe              // Bad: Easy to forget
var running atomic.Bool          var running int32 // atomic
running.Store(true)              atomic.StoreInt32(&running, 1)
running.Load()                   running == 1 // race!

© cxuu, Apache-2.0. 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/go-concurrency of cxuu/golang-skills.

• SKILL.md
• references/ADVANCED-PATTERNS.md
• references/BUFFER-POOLING.md
• references/GOROUTINE-PATTERNS.md
• references/SYNC-PRIMITIVES.md

Open the folder on GitHubat commit 91f0c2e