golang-performance

golang-performance is a skill for Claude Code from samber/cc-skills-golang. It costs 130 tokens per session (2,226 once invoked), scanned A, original, MIT.

A guide to improving the performance of Go programs after profiling identifies a bottleneck. Profiling measures where a program spends time or memory before changes are made.

In plain words
What is it for?
Use it to review a Go package or service, investigate a hot path, or choose changes such as reducing allocations, improving data layout, or tuning concurrency after measurement.
Why use it?
It helps match a measured problem to an appropriate fix instead of making guesses or optimising code that is not slow. It covers CPU, memory, garbage collection, I/O, concurrency, caching, and algorithms.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions subagents; names the AskUserQuestion tool; mentions Claude Code.

Part of the cc-skills-golang plugin — 46 skills shipped together

Good fit Use it to review a Go package or service, investigate a hot path, or choose changes such as reducing allocations, improving data layout, or tuning concurrency after measurement.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/samber/cc-skills-golang/golang-performance
About the project

samber/cc-skills-golang is a collection of reusable agent instructions for Go development, covering areas such as the language, testing, security, and observability. It is for coding agents assisting with production-oriented Golang projects. The catalogue entries are its Go-specific skills, rule, plugin, and instruction.

samber/cc-skills-golang · 3,232 stars · on GitHub · skills.sh

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add samber/cc-skills-golang --skill golang-performance
Clone the repo
git clone --depth 1 https://github.com/samber/cc-skills-golang

Made for: Claude Code.

Or install cc-skills-golang, the plugin that ships this one along with the rest of its 46 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for golang-performance

README.md
[![agentmods](https://agentmods.dev/badge/skills/samber/cc-skills-golang/golang-performance/github.svg)](https://agentmods.dev/skills/samber/cc-skills-golang/golang-performance)
Your own site
<a href="https://agentmods.dev/skills/samber/cc-skills-golang/golang-performance"><img src="https://agentmods.dev/badge/skills/samber/cc-skills-golang/golang-performance/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for golang-performance

Your own site · 80×15
<a href="https://agentmods.dev/skills/samber/cc-skills-golang/golang-performance"><img src="https://agentmods.dev/badge/skills/samber/cc-skills-golang/golang-performance.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 130 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,226 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • Socket pass 20 May 2026
  • Snyk pass 20 May 2026
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00130 $0.02226
Opus 5 $0.00065 $0.01113
Sonnet 5 $0.00026 $0.00445
Haiku 4.5 $0.00013 $0.00223

Measured 8d ago against content hash 80a4e7aa3b34, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

golang-performance scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

allowed-tools: Read Edit Write Glob Grep Bash(go:*) Bash(golangci-lint:*) Bash(git:*) Agent WebFetch Bash(benchstat:*) Bash(fieldalignment:*) Bash(staticcheck:*) Bash(curl:*) Bash(fgprof:*) Bash(perf:*) WebSearch AskUser
Origin

Copies of this mod

3 near-identical copies found in the catalogue:

skills/golang-performance/SKILL.md · 122 lines

How it starts

The opening of the file, as written. The whole thing — 122 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Persona: You are a Go performance engineer. You never optimize without profiling first — measure, hypothesize, change one thing, re-measure.

Thinking mode: Reason as thoroughly as possible for performance optimization — shallow analysis misidentifies bottlenecks and deep reasoning ensures the right optimization is applied to the right problem. On Claude Code, use ultrathink to trigger extended thinking explicitly.

Orchestration mode: Fan out the three sub-agents described in Review mode (architecture) (allocation and memory layout, I/O and concurrency, algorithmic complexity and caching) for a broad architectural performance review. A single hot-path review stays sequential; fan-out only pays off at package/service scope. On Claude Code, use ultracode to opt into multi-agent orchestration explicitly.

Modes:

  • Review mode (architecture) — broad scan of a package or service for structural anti-patterns (missing connection pools, unbounded goroutines, wrong data structures). Use up to 3 parallel sub-agents split by concern: (1) allocation and memory layout, (2) I/O and concurrency, (3) algorithmic complexity and caching.
  • Review mode (hot path) — focused analysis of a single function or tight loop identified by the caller. Work sequentially; one sub-agent is sufficient.
  • Optimize mode — a bottleneck has been identified by profiling. Follow the iterative cycle (define metric → baseline → diagnose → improve → compare) sequentially — one change at a time is the discipline.

Dependencies:

  • benchstat: go install golang.org/x/perf/cmd/benchstat@latest

Go Performance Optimization

Core Philosophy

  1. Profile before optimizing — intuition about bottlenecks is wrong ~80% of the time. Use pprof to find actual hot spots (→ See samber/cc-skills-golang@golang-troubleshooting skill)
  2. Allocation reduction yields the biggest ROI — Go's GC is fast but not free. Reducing allocations per request often matters more than micro-optimizing CPU
  3. Document optimizations — add code comments explaining why a pattern is faster, with benchmark numbers when available. Future readers need context to avoid reverting an "unnecessary" optimization

Read the full file on GitHub · 122 lines

Files

What ships with it

8 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago Changed 80a4e7aa3b34
  2. 10d ago Changed 52630c1ab074
  3. 13d ago First seen · 122 lines · 130 tokens per session scan A fba9034aa666

Subscribe to this mod's changes

golang-performance is a skill published in the GitHub repository samber/cc-skills-golang (3,232 stars, last pushed 5d ago), licensed MIT. It adds 130 tokens to every session and 2,226 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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