CLI Conventions Skill

Purpose

Encode this project's argv/stdout contract so a dev-loop agent extends the CLI
without smuggling untested plumbing past the quality gate. This is the
project-scoped skill the forge↔project contract expects every project to bind
at least one of (skills[] in .forge/project.json) — replace or extend it
as the project's real behaviour grows past the starter's single greet
function.

When to use

• Adding a new CLI flag, subcommand, or argument.
• Changing how output is formatted or written.
• Reviewing whether a change belongs in main() or in a pure function.

The rule

Real behaviour lives in small, pure, testable functions (greet in
src/index.ts is the template — replace it, keep the shape). main(argv)
stays thin: parse argv, call the pure function(s), write to stdout. The
if (import.meta.url === ...) guard is what lets test/*.test.ts import the
module without executing main as a side effect — keep it when the entry
point changes.

Verification workflow

1. Add or extend a pure function; write its node:test case FIRST, with a
   distinctive value (mirroring greet('sentinel-42')) so a stub
   implementation that ignores its input is caught.
2. npm test — fast, deterministic, must fail before the behaviour exists.
3. npm run build (tsc → dist/) before npm run acceptance, which runs the
   BUILT CLI — a read-back against the actually-running binary, never the
   source.