Create CLI

Design CLI surface area (syntax + behavior), human-first, script-friendly.

Do This First

• Read agent-scripts/skills/create-cli/references/cli-guidelines.md and apply it as the default rubric.

• Upstream/full guidelines: https://clig.dev/ (propose changes: https://github.com/cli-guidelines/cli-guidelines)

• Ask only the minimum clarifying questions needed to lock the interface.

Clarify (fast)

Ask, then proceed with best-guess defaults if user is unsure:

• Command name + one-sentence purpose.

• Primary user: humans, scripts, or both.

• Input sources: args vs stdin; files vs URLs; secrets (never via flags).

• Output contract: human text, --json, --plain, exit codes.

• Interactivity: prompts allowed? need --no-input? confirmations for destructive ops?

• Config model: flags/env/config-file; precedence; XDG vs repo-local.

• Platform/runtime constraints: macOS/Linux/Windows; single binary vs runtime.

Deliverables (what to output)

When designing a CLI, produce a compact spec the user can implement:

• Command tree + USAGE synopsis.

• Args/flags table (types, defaults, required/optional, examples).

• Subcommand semantics (what each does; idempotence; state changes).

• Output rules: stdout vs stderr; TTY detection; --json/--plain; --quiet/--verbose.

• Error + exit code map (top failure modes).

• Safety rules: --dry-run, confirmations, --force, --no-input.

• Config/env rules + precedence (flags > env > project config > user config > system).

• Shell completion story (if relevant): install/discoverability; generation command or bundled scripts.

• 5–10 example invocations (common flows; include piped/stdin examples).

Default Conventions (unless user says otherwise)

• -h/--help always shows help and ignores other args.

• --version prints version to stdout.

• Primary data to stdout; diagnostics/errors to stderr.

• Add --json for machine output; consider --plain for stable line-based text.

• Prompts only when stdin is a TTY; --no-input disables prompts.

• Destructive operations: interactive confirmation + non-interactive requires --force or explicit --confirm=....

• Respect NO_COLOR, TERM=dumb; provide --no-color.

• Handle Ctrl-C: exit fast; bounded cleanup; be crash-only when possible.

Templates (copy into your answer)

CLI spec skeleton

Fill these sections, drop anything irrelevant:

1. Name: mycmd

2. One-liner: ...

3. USAGE:

   • mycmd [global flags] <subcommand> [args]

4. Subcommands:

   • mycmd init ...
   • mycmd run ...

5. Global flags:

   • -h, --help
   • --version
   • -q, --quiet / -v, --verbose (define exactly)
   • --json / --plain (if applicable)

6. I/O contract:

   • stdout:
   • stderr:

7. Exit codes:

   • 0 success
   • 1 generic failure
   • 2 invalid usage (parse/validation)
   • (add command-specific codes only when actually useful)

8. Env/config:

   • env vars:
   • config file path + precedence:

9. Examples:

   • …

Notes

• Prefer recommending a parsing library (language-specific) only when asked; otherwise keep this skill language-agnostic.

• If the request is “design parameters”, do not drift into implementation.