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: (propose changes: )
• 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:

Name: mycmd

One-liner: ...

USAGE:

- mycmd [global flags] [args]

Subcommands:

- mycmd init ...
- mycmd run ...

Global flags:

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

I/O contract:

- stdout:
- stderr:

Exit codes:

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

Env/config:

- env vars:
- config file path + precedence:

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.