JetBrains/go-modern-guidelines

This repository contains guidelines 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.

All coding agents tend to generate outdated Go.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

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 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.

The marketplace integrations run a small CLI that is installed on first use with go install. Because of that, the Go toolchain must be installed and available on your PATH.

The CLI is installed into a local cache (for example ~/.cache/go-modern-guidelines) and never modifies your project. It targets Go 1.25 or newer; on an older Go it still works as long as automatic toolchain switching is enabled (GOTOOLCHAIN=auto, the default), which lets Go fetch a compatible toolchain on first run.