best-practices

best-practices is a cursor rule for coding agents from ofershap/go-best-practices. It costs 259 tokens per session, scanned A, original, MIT.

A set of Go coding rules covering error handling, logging, context use, modern Go 1.22 or later loops, and safe goroutine lifecycles.

In plain words
What is it for?
Use it when writing or reviewing Go code to require wrapped errors, structured logging with slog, context-aware functions, standard error checks, and stoppable goroutines.
Why use it?
It keeps Go code consistent and helps prevent lost error context, unmanaged background work, and patterns that conflict with current language practices.

Cursor rule

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.

agentmods
npx agentmods add rules/ofershap/go-best-practices/best-practices
Clone the repo
git clone --depth 1 https://github.com/ofershap/go-best-practices

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 best-practices

README.md
[![agentmods](https://agentmods.dev/badge/rules/ofershap/go-best-practices/best-practices.svg)](https://agentmods.dev/rules/ofershap/go-best-practices/best-practices)
Your own site
<a href="https://agentmods.dev/rules/ofershap/go-best-practices/best-practices"><img src="https://agentmods.dev/badge/rules/ofershap/go-best-practices/best-practices.svg" alt="Measured on agentmods" height="20"></a>
Per session 259 This file is loaded in full into every session.
When invoked 259 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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 $0.00259 $0.00259
Opus 5 $0.00130 $0.00130
Sonnet 5 $0.00052 $0.00052
Haiku 4.5 $0.00026 $0.00026

Measured 3d ago against content hash cea0dc8ee7e7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

best-practices scanned grade A with 0 findings 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 3d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

rules/best-practices.mdc · 19 lines

What it actually says

When writing or modifying Go code:

  1. Wrap all errors with context — Use fmt.Errorf("context: %w", err) instead of return err. Never propagate bare errors.

  2. Use slog for logging — Use log/slog (slog.Info, slog.Error, slog.Debug) instead of log package. No log.Printf.

  3. Context as first parameter — Pass context.Context as the first argument to functions. Never store context in struct fields.

  4. Error checking — Use errors.Is(err, target) and errors.As(err, &target) for error checks. Never use == or type assertion on errors.

  5. Go 1.22+ patterns — Prefer for i := range n over for i := 0; i < n; i++. Do not add unnecessary loop variable shadow copies (Go 1.22 fixed capture).

  6. Goroutine lifecycle — Every goroutine must have an exit path. Use context cancellation, done channels, or errgroup. Never spawn unbounded goroutines that cannot stop.

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. 3d ago First seen · 19 lines · 259 tokens per session scan A cea0dc8ee7e7

Subscribe to this mod's changes

best-practices is a cursor rule published in the GitHub repository ofershap/go-best-practices (2 stars, last pushed 6mo ago), licensed MIT. It adds 259 tokens to every session, about $0.0013 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.