Go Modern Guidelines — AI skill for Claude Code

[](https://confluence.jetbrains.com/display/ALL/JetBrains+on+GitHub)

Modern Go Guidelines

This repository contains [guidelines](https://github.com/JetBrains/go-modern-guidelines/blob/main/plugin/skills/use-modern-go/SKILL.md) for code agents that help them write modern Go code.

For example, an agent with these guidelines uses `max(a, b)` instead of an if-else block, `slices.Contains` instead of a manual loop, `cmp.Or(a, b, c)` instead of a chain of nil checks. It also knows about recent additions like `new(42)` to get a pointer to a value and `errors.AsType[T](err)` for type-safe error matching—both from Go 1.26.

The guidelines cover the most useful features from Go 1.0 through Go 1.27, including everything targeted by the `modernize` analyzer. An agent will:

• Detect the project's Go version from go.mod
• Use language features and stdlib additions available up to and including that version
• Prefer modern idioms over older patterns

Motivation

All coding agents tend to generate outdated Go. Two reasons:

1. **Training data lag.** Models don't know about features added after their training cutoff. They can't use `errors.AsType[T]` (Go 1.26) if they've never seen it.

2. **Frequency bias.** Even for features the model knows, it often picks older patterns. There's more `for i := 0; i < n; i++` in the training data than `for i := range n`, so that's what comes out.

These guidelines fix both problems by giving the agent an explicit reference.

This aligns with the Go team's direction. The `modernize` analyzer exists to automatically update existing code to use newer idioms (see [this talk](https://www.youtube.com/watch?v=_VePjjjV9JU) from the Go team). These guidelines serve the same goal for new code: agents write modern Go from the start, so there's less to fix later.

Requirements

The marketplace integrations run a small CLI that is installed on first use with `go install`. Because of th