go-docs - SKILL.md Agent Skill

name: go-docs description: Go documentation conventions — a doc comment on every exported function, struct, type, and package, package comments in a dedicated doc.go for multi-file packages, godoc style (complete sentences beginning with the identifier's name), and LLM-ready CLI reference generation for cobra tools via a docgen helper built on cobra/doc. Use when writing or reviewing doc comments or godoc in Go code, documenting an exported Go API, package, function, or struct, deciding where a package comment or doc.go belongs, or generating markdown CLI documentation for a cobra-based Go tool. license: MIT

Go documentation conventions

Doc comments are the API's reference manual: godoc, pkg.go.dev, and editors render them, and LLM coding agents read them to learn an API. These rules say where they go and what they look like; for the code itself see the go-style skill.

1. Every exported identifier gets a doc comment

Every exported function, method, struct and other type, interface, and package-level const or var (or grouped block) carries a doc comment — no exceptions for "obvious" ones. The comment is a complete sentence that begins with the identifier's name and states what the caller may rely on:

// Parse splits a KEY=VALUE line into its key and value, trimming whitespace
// around both. It returns an error when the separator is missing.
func Parse(line string) (key, value string, err error) {

Start with the name: // Loader reads …, never // This function reads ….
Document behavior and invariants, not implementation — what holds true for the caller.
Mark deprecations with a Deprecated: paragraph so tooling can flag callers.

2. Package comments live in doc.go

Every package has exactly one package comment, beginning Package <name> …. In a package with more than one non-test file, put it in a dedicated doc.go that holds only the comment and the package clause, so it never moves when files are reorganized:

// Package keyval stores and parses KEY=VALUE pairs for the demo service.
//
// A Store is safe for concurrent readers; writes must be serialized by the
// caller.
package keyval

When the package has a single non-test file, the comment sits at the top of that file instead — a doc.go beside one source file is noise.

3. Cobra CLIs generate an LLM-ready reference

A cobra command tree already knows every command, flag, and example — publish it as one markdown page per command (mycli.md, mycli_serve.md, …) that humans, search engines, and LLMs can read (see the cobra.dev guide):

Expose the root command from the command package, and fill in Short, Long, an Example, and GroupID on every command — the generators publish exactly that metadata:
```
// Root exposes the root command for main and the docgen tool.
func Root() *cobra.Command { return rootCmd }
```
Copy templates/docgen/main.go to internal/tools/docgen/main.go and point its import at your command package. It sets root.DisableAutoGenTag = true so the output is reproducible (no timestamp footer), and renders markdown — optionally with YAML front matter — man, or reST via the github.com/spf13/cobra/doc generators.
The helper imports your application's packages, so it lives in the application module and runs with go run — it is not a pinned developer tool in tools/go.mod (see the go-project skill):
```
docs: ## Regenerate the CLI reference (docs/cli) from the cobra command tree
    go run ./internal/tools/docgen -out docs/cli -format markdown
```
Commit the generated docs/cli and refresh it whenever commands or flags change, so the reference never drifts from the binary.