name: create-cli description: > Design command-line interface parameters and UX: arguments, flags, subcommands, help text, output formats, error messages, exit codes, prompts, config/env precedence, and safe/dry-run behavior. Use when you’re designing a CLI spec (before implementation) or refactoring an existing CLI’s surface area for consistency, composability, and discoverability.

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:

Name:
```
mycmd
```
One-liner:
```
...
```

USAGE:

mycmd [global flags] <subcommand> [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.

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] <subcommand> [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:

Create cli

Create CLI

Do This First

Clarify (fast)

Deliverables (what to output)

Default Conventions (unless user says otherwise)

Templates (copy into your answer)

CLI spec skeleton

Notes

Create CLI

Do This First

Clarify (fast)

Deliverables (what to output)

Default Conventions (unless user says otherwise)

Templates (copy into your answer)

CLI spec skeleton

Notes