Stdlib First

Assume the standard library already has it until go doc proves otherwise. Every hand-rolled helper is a liability: untested, unnamed, invisible to the next reader who already knows the stdlib name.

Lookup workflow

1. go doc <pkg> for the package index; go doc <pkg>.<Symbol> for one API.
2. go doc -all <pkg> | rg -i <term> when the symbol name is unknown.
3. Search across std: pkg.go.dev via [[z-go-pkg]], or the coverage map below.
4. Nothing in std → check golang.org/x (x/sync, x/time, x/text, x/crypto, x/exp).
5. Only then a third-party dependency — and justify it (see gate below).

Never quote an API from memory into code — signatures drift between releases. Verify with go doc at the version in go.mod.

Coverage map — task → package