What is cli-developer?

A guide for creating command-line tools, which are programs operated through a terminal. It covers command arguments, interactive questions, progress displays, shell tab completion, packaging, and support across operating systems.

Use it to build commands, parse options, add prompts and progress indicators, provide tab completion, package releases, and support multiple platforms.

It helps handle the details that make terminal programs clear and usable. It also reduces the work needed to distribute one tool to people using different systems.

cli-developer — Skill for Claude Code and Codex by johnefemer

Install

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.

Any agent

npx skills add johnefemer/skillfish --skill cli-developer

Clone the repo

git clone --depth 1 https://github.com/johnefemer/skillfish

Made for: Claude Code, Codex.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/johnefemer/skillfish/cli-developer/github.svg)](https://agentmods.dev/skills/johnefemer/skillfish/cli-developer)

Your own site

<a href="https://agentmods.dev/skills/johnefemer/skillfish/cli-developer"><img src="https://agentmods.dev/badge/skills/johnefemer/skillfish/cli-developer/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/johnefemer/skillfish/cli-developer"><img src="https://agentmods.dev/badge/skills/johnefemer/skillfish/cli-developer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 9,102 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 2 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin unknown No closer match found in the catalogue.

Token cost

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	$0.00000	$0.09102
Opus 5.5	$0.00000	$0.03641
Sonnet 5.5	$0.00000	$0.01820
Haiku 4.5	$0.00000	$0.00910

Measured 2mo ago against content hash c3672287ab07, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

cli-developer scanned grade A with 2 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 2mo 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

import urllib.request

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

import { execFileSync } from "node:child_process";

skills/cli-developer/SKILL.md · 1,285 lines

The source is not reproduced here

No licence file

Read it on GitHub

Changes

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.

2mo ago First seen · 1,285 lines · 0 tokens per session scan A c3672287ab07

Subscribe to this mod's changes

cli-developer is a skill published in the GitHub repository johnefemer/skillfish (4 stars, last pushed 4d ago), with no licence file. It costs nothing until one of its globs matches a file; then it loads 9,102 tokens. A static security scan graded it A with 2 findings (makes network calls, runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

cli-developer next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
cli-developerjohnefemer/skillfish	Skill	4	4d ago	none	A	0	Claude Code, Codex
imagegenopenai/codex	Skill	133k	yesterday	Apache-2.0	A	113	Codex
playwright-climicrosoft/playwright	Skill	99k	yesterday	Apache-2.0	A	19	Claude Code
local-ai-agentsmicrosoft/ai-agents-for-beginners	Skill	79k	4d ago	MIT	A	200	Claude Code, Codex
systematic-debuggingobra/superpowers	Skill	313k	3d ago	MIT	A	21	Claude Code
next-cache-components-adoptionvercel/next.js	Skill	143k	yesterday	MIT	A	95	Claude Code
next-partial-prefetching-adoptionvercel/next.js	Skill	143k	yesterday	MIT	A	103	Claude Code

cli-developer

Getting it into your agent

Wrote this? Show the measurements

What it costs to keep this loaded

Grade A, and why

Makes network callslowCapability

Runs shell commandslowCapability

The source is not reproduced here

No licence file

What this file has done since we first saw it

cli-developer compared with skills from other repositories