claude-code-system-prompts/system-prompts/skill-run-cli-tool-example.md

Example: CLI tool

CLIs are the simplest case — there's usually no background process to manage, no ports, no lifecycle. The skill focuses on installation, representative invocations, and testing.

What matters

• How to get the binary on PATH. Installed globally? Run via npx/uv run? Built to ./target/release/foo? Be explicit.
• Two or three example invocations that cover the main use cases. Include expected output so a reader can tell it worked.
• Exit codes if they're meaningful (e.g. linter returns 1 on findings).
• Stdin behavior if the tool reads from stdin.

Example snippet

---

name: run-mytool description: Build, install, and run mytool. Use when asked to run mytool, test it, or verify it's installed correctly.

Setup

pip install -e .

This puts mytool on PATH. Verify:

mytool --version
# → mytool 0.3.1

Run

Process a single file:

mytool process input.json
# → Processed 42 records, wrote output.json

Read from stdin, write to stdout:

cat input.json | mytool process -

Lint a directory (exits non-zero on problems):

mytool lint ./src
echo $?  # 0 if clean, 1 if issues found

Test

pytest

Keep it short

A CLI's run skill can be very compact. Don't pad it with every flag — the --help output covers that. Just show enough that an agent can (a) build it, (b) confirm it works, (c) run the tests.