Skill v1.0.0

version: "1.0.0" name: cli-tool-skill-authoring description: "Write a SKILL.md that lets any CLI agent correctly discover and operate an existing command-line tool. Use when asked to \"add a skill for X tool\", \"make this CLI agent-operable\", or document a binary/script for future agent sessions."

Goal

Produce a SKILL.md that a different agent, with zero prior context on the tool, can read once and then use the tool correctly and safely.

Structure that works

1. Frontmatter — name (kebab-case, matches the tool) and description (one line, front-load when to use it, not what it is — this is what discovery matches against).
2. One-paragraph mental model — what the tool actually does and its one core design decision (e.g. "picks the clipboard mechanism automatically", "never touches disk"). Not a feature list.
3. "Before using it" preflight — how to confirm the tool is installed/available and how to self-diagnose common environment issues (a --check/--doctor/--version equivalent), plus the install command if it's missing.
4. Core usage — the 2-4 invocation shapes that cover 90% of real use, as runnable examples, not a syntax diagram.
5. Agent-relevant flags table — NOT the full --help dump. Only flags an agent would actually need to reach for, each with when to use it, not just what it does. Omit flags aimed at interactive humans (like custom color themes).
6. Exit codes / failure modes — especially non-obvious ones (e.g. "exit 3 means refused-not-failed, here's the real fix"). Agents need to branch on these programmatically.
7. The one sharp edge — every real tool has exactly one thing that silently does the wrong thing if you don't know about it (a size limit that truncates silently, a flag that only works in one mode, a default that changes based on environment). Give it its own section, not a buried bullet.
8. Composability recipes — if the tool is meant to be piped/combined with standard tools (sed/awk/grep/tail, jq, xargs), show 3-5 concrete one-liners rather than describing the pattern abstractly.
9. How to verify it worked — don't let the agent trust a bare exit 0. State what to actually check (re-read the output, run a paired read-back command, grep a log) to confirm the side effect really happened.

Non-negotiable process

• Every operational claim MUST be grounded in the tool's actual source or an actual command run before it goes in the doc. Do not write "X will warn about Y" from memory or plausible inference — grep the source for where that warning would be emitted, or run the command and paste the real output. A plausible-sounding but false claim in an agent-facing skill doc causes silent downstream failures, because the next agent will trust it and act on it without re-verifying.
• Keep the flags table to what's actually needed; a full --help dump duplicates --help and gives the reading agent nothing extra.
• If the tool has an environment-variable equivalent for common flags, list it — agents scripting non-interactively often prefer env vars.
• Link back to full docs/README at the end rather than duplicating everything.