supercli: Skill for Claude Code

.agents/skills/write-a-skill/SKILL.md

write-a-skill is a skill for Claude Code, Codex from javimosch/supercli. It costs 35 tokens per session (664 once invoked), scanned A, a copy of write-a-skill, MIT.

A guide for creating new skills for a coding agent, including their instructions, supporting reference files, examples, and utility scripts. It also describes how to gather requirements and review a draft.

In plain words
What is it for?
Use it when designing, writing, reviewing, or packaging a new agent skill for a particular task or domain.
Why use it?
It gives a consistent structure for agent instructions and helps keep long or detailed material in separate files instead of making the main skill difficult to use.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

This is javimosch/supercli's own configuration. It tells Claude Code and Codex how to work on supercli itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything supercli configures →

Reuse

Borrowing it

Nothing to install: this file belongs to javimosch/supercli. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/javimosch/supercli/master/.agents/skills/write-a-skill/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/javimosch/supercli

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.

agentmods badge for write-a-skill

README.md
[![agentmods](https://agentmods.dev/badge/skills/javimosch/supercli/write-a-skill/github.svg)](https://agentmods.dev/skills/javimosch/supercli/write-a-skill)
Your own site
<a href="https://agentmods.dev/skills/javimosch/supercli/write-a-skill"><img src="https://agentmods.dev/badge/skills/javimosch/supercli/write-a-skill/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.

agentmods 80×15 button for write-a-skill

Your own site · 80×15
<a href="https://agentmods.dev/skills/javimosch/supercli/write-a-skill"><img src="https://agentmods.dev/badge/skills/javimosch/supercli/write-a-skill.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 35 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 664 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00035 $0.00664
Opus 5.5 $0.00014 $0.00266
Sonnet 5.5 $0.00007 $0.00133
Haiku 4.5 $0.00003 $0.00066

Measured today against content hash be8f20e66309, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

write-a-skill 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 today.

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.

Origin

This is a copy

100% identical to write-a-skill — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/write-a-skill/SKILL.md · 118 lines

How it starts

The opening of the file, as written. The whole thing — 118 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Writing Skills

Process

  1. Gather requirements - ask user about:

    • What task/domain does the skill cover?
    • What specific use cases should it handle?
    • Does it need executable scripts or just instructions?
    • Any reference materials to include?
  2. Draft the skill - create:

    • SKILL.md with concise instructions
    • Additional reference files if content exceeds 500 lines
    • Utility scripts if deterministic operations needed
  3. Review with user - present draft and ask:

    • Does this cover your use cases?
    • Anything missing or unclear?
    • Should any section be more/less detailed?

Skill Structure

skill-name/
├── SKILL.md           # Main instructions (required)
├── REFERENCE.md       # Detailed docs (if needed)
├── EXAMPLES.md        # Usage examples (if needed)
└── scripts/           # Utility scripts (if needed)
    └── helper.js

SKILL.md Template

---
name: skill-name
description: Brief description of capability. Use when [specific triggers].
---

# Skill Name

## Quick start

[Minimal working example]

## Workflows

[Step-by-step processes with checklists for complex tasks]

## Advanced features

[Link to separate files: See [REFERENCE.md](REFERENCE.md)]

Description Requirements

The description is the only thing your agent sees when deciding which skill to load. It's surfaced in the system prompt alongside all other installed skills. Your agent reads these descriptions and picks the relevant skill based on the user's request.

Goal: Give your agent just enough info to know:

  1. What capability this skill provides
  2. When/why to trigger it (specific keywords, contexts, file types)

Format:

  • Max 1024 chars
  • Write in third person
  • First sentence: what it does
  • Second sentence: "Use when [specific triggers]"

Good example:

Extract text and tables from PDF files, fill forms, merge documents. Use when working with PDF files or when user mentions PDFs, forms, or document extraction.

Read the full file on GitHub · 118 lines

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.

  1. today First seen · 118 lines · 35 tokens per session scan A be8f20e66309

Subscribe to this mod's changes

write-a-skill is a skill published in the GitHub repository javimosch/supercli (56 stars, last pushed today), licensed MIT. It adds 35 tokens to every session and 664 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to write-a-skill, differing in 0 lines, and is treated as a copy.

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