Python CLI

Python CLI

Use for Python terminal applications where user experience, automation behavior, and command contracts matter.

Defaults

• Simple commands: argparse + optional rich-argparse
• Multi-command apps: Typer + Rich
• Real TUI: load skills/textual/SKILL.md
• Presentation: load skills/rich/SKILL.md
• Implementation: load skills/python/SKILL.md
• Final checks: load skills/verification/SKILL.md

Workflow

1. Inspect command entrypoints, parser, help text, scripts, and tests.
2. Separate parsing, orchestration, business logic, and rendering.
3. Define stdout/stderr, exit codes, interactive behavior, and machine-readable output.
4. Implement the smallest changed command surface.
5. Verify help, success path, failure path, and automation mode.

UX Rules

• --help must be accurate, scannable, and current.
• Success exits 0; failures exit non-zero.
• Machine-readable output goes to stdout; human-readable errors go to stderr.
• Interactive prompts must be optional when CI/scripts may call the command.
• Verbose/debug output is opt-in.
• Color and Rich formatting help usability but are not correctness.

Safety Rules

• Secrets are never printed.
• Dangerous operations require explicit flags or confirmation.
• File paths and overwrites are validated.
• Network, subprocess, and filesystem side effects are visible from command names or flags.

Suggested Layout

src/myapp/
├── cli/       # parsing, dispatch, commands
├── core/      # reusable logic
├── services/  # orchestration
├── models/    # typed inputs/outputs/config
└── views/     # terminal rendering

Verification

• uv run python -m myapp --help
• command success path
• command failure path
• stdout/stderr behavior
• exit codes
• interactive and non-interactive modes