Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add oborchers/fractional-cto --skill cli-architecturegit clone --depth 1 https://github.com/oborchers/fractional-ctoWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/oborchers/fractional-cto/cli-architecture)<a href="https://agentmods.dev/skills/oborchers/fractional-cto/cli-architecture"><img src="https://agentmods.dev/badge/skills/oborchers/fractional-cto/cli-architecture/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/oborchers/fractional-cto/cli-architecture"><img src="https://agentmods.dev/badge/skills/oborchers/fractional-cto/cli-architecture.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00092 | $0.01525 |
| Opus 5.5 | $0.00037 | $0.00610 |
| Sonnet 5.5 | $0.00018 | $0.00305 |
| Haiku 4.5 | $0.00009 | $0.00153 |
Grade A, and why
cli-architecture scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 134 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLI Architecture for Python Packages
Not every package needs a CLI, but when it does, the structure and framework choice have long-term consequences for maintenance, discoverability, and user experience. The Python ecosystem has converged on clear patterns -- 7 out of 13 surveyed top packages (httpx, Black, Hatch, Flask, cookiecutter, rich-cli, Typer itself) use Click directly. Typer wraps Click and is gaining adoption for simpler CLIs. argparse remains the choice when zero external dependencies is a hard requirement.
Framework Selection
Choose the CLI framework based on your constraints and complexity:
| Your CLI | Use This Framework | Why |
|---|---|---|
| Zero dependencies required | argparse (stdlib) | No external deps; used by pytest, pre-commit, Django |
| Simple-to-moderate, modern Python (3.10+) | Typer | Less boilerplate, leverages type hints, Click underneath |
| Complex with subcommand groups, plugins, custom types | Click | Battle-tested, explicit decorators, deep customization |
| Performance-critical tool | Clap (Rust) + maturin | Used by ruff, uv; not a Python CLI at all |
What top packages use:
| Package | Framework | Reason |
|---|---|---|
| Flask, Hatch, Black, httpx, cookiecutter | Click | Complex CLIs, plugin systems, mature ecosystem |
| fastapi-cli | Typer | Same author, type-hint-driven API |
| pytest, pre-commit | argparse | Zero-dependency policy |
| ruff, uv | Clap (Rust) | Performance-critical, not Python CLIs |
Click has ~530M monthly downloads; Typer has ~100M and growing. Typer IS Click underneath -- choosing Typer means you are using Click with a type-hint-based API surface. The Python Packaging User Guide now demonstrates Typer as its primary CLI example.
CLI Module Layout
Two patterns, chosen by CLI complexity:
Single cli.py file (small-to-medium CLIs, used by Flask, httpx, pre-commit, fastapi-cli):
src/my_package/
__init__.py
__main__.py # delegates to cli.main()
cli.py # all CLI logic here
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 3d ago First seen · 134 lines · 92 tokens per session scan A a58e57c5a7e2
cli-architecture is a skill published in the GitHub repository oborchers/fractional-cto (32 stars, last pushed 3d ago), licensed MIT. It adds 92 tokens to every session and 1,525 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-10-13.
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