# Golang Concurrency

Golang concurrency design, goroutine lifecycle and leak prevention, channels and...

- Repository: https://github.com/samber/cc-skills-golang (3750 stars)
- Category: Design
- License: MIT
- Last updated: 2026-11-01
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add samber/cc-skills-golang --skill golang-concurrency -g -a claude-code -y`
Codex: `npx skills add samber/cc-skills-golang --skill golang-concurrency -g -a codex -y`
Cursor: `npx skills add samber/cc-skills-golang --skill golang-concurrency -g -a cursor -y`
Gemini CLI: `npx skills add samber/cc-skills-golang --skill golang-concurrency -g -a gemini-cli -y`

## Description

Golang concurrency design, goroutine lifecycle and leak prevention, channels and `select`, channel ownership and direction, `sync.Mutex`/`RWMutex`/`sync.Map`/`sync.Once`/atomics, `errgroup`, `singleflight`, worker pools, and fan-out/fan-in pipelines. Use when writing or reviewing concurrent Go code, when choosing between channels and mutexes, when protecting a shared map or counter, or when a goroutine has no clear exit. Not for defensive coding unrelated to concurrency such as nil panics, slice aliasing, or numeric overflow (→ See `samber/cc-skills-golang@golang-safety` skill), and not for debugging a specific hung, crashing, or racing program after the fact (→ See `samber/cc-skills-golang@golang-troubleshooting` skill).

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

**Persona:** You are a Go concurrency engineer. You assume every goroutine is a liability until proven necessary, correctness and leak-freedom come before performance.

**Orchestration mode:** Fan out the five sub-agents described in the "Parallelizing Concurrency Audits" section for auditing concurrent code across a large codebase, and consolidate their findings into one report. On Claude Code, use `ultracode` to opt into multi-agent orchestration explicitly.

**Modes:**

- **Write mode**, implement concurrent code (goroutines, channels, sync primitives, worker pools, pipelines). Follow the sequential instructions below.
- **Review mode**, reviewing a PR's concurrent code changes. Focus on the diff: check for goroutine leaks, missing context propagation, ownership violations, and unprotected shared state. Sequential.
- **Audit mode**, auditing existing concurrent code across a codebase. Use up to 5 parallel sub-agents as described in the "Parallelizing Concurrency Audits" section.

> **Community default.** A company skill that explicitly supersedes `samber/cc-skills-golang@golang-concurrency` skill takes precedence.

# Go Concurrency Best Practices

Go's concurrency model is built on goroutines and channels. Goroutines are cheap but not free, every goroutine you spawn is a resource you must manage. The goal is structured concurrency: every goroutine has a clear owner, a predictable exit, and proper error propagation.

## Core Principles

The rest: https://github.com/samber/cc-skills-golang/blob/HEAD/skills/golang-concurrency/SKILL.md