markdown-writing

markdown-writing is a skill for Claude Code, Codex from edloidas/skills. It costs 67 tokens per session (2,031 once invoked), scanned A, original, MIT.

A guide to writing readable Markdown for README files, documentation, pull requests, issues, release notes, and changelogs. It covers syntax supported by GitHub and other places where Markdown may appear.

In plain words
What is it for?
Use it when creating or improving repository documentation, pull request text, issue text, release notes, changelogs, task lists, collapsible sections, alerts, or Mermaid diagrams.
Why use it?
It helps you choose formatting that will display correctly and keeps important information easy to find. It also reduces the risk that GitHub-specific features look broken elsewhere.

Skill for Claude CodeCodex

Written for Claude Code and Codex: argument-hint in frontmatter, but also agents/openai.yaml present. Also seen: mentions Claude Code; mentions Codex; mentions OpenCode.

Part of the write plugin — 1 skill shipped together

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.

agentmods
npx agentmods add skills/edloidas/skills/markdown-writing
Any agent
npx skills add edloidas/skills --skill markdown-writing
Clone the repo
git clone --depth 1 https://github.com/edloidas/skills

Made for: Claude Code, Codex.

Or install write, the plugin that ships this one along with the rest of its 1 skill.

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 markdown-writing

README.md
[![agentmods](https://agentmods.dev/badge/skills/edloidas/skills/markdown-writing.svg)](https://agentmods.dev/skills/edloidas/skills/markdown-writing)
Your own site
<a href="https://agentmods.dev/skills/edloidas/skills/markdown-writing"><img src="https://agentmods.dev/badge/skills/edloidas/skills/markdown-writing.svg" alt="Measured on agentmods" height="20"></a>
Per session 67 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,031 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00067 $0.02031
Opus 5 $0.00034 $0.01015
Sonnet 5 $0.00013 $0.00406
Haiku 4.5 $0.00007 $0.00203

Measured 2d ago against content hash f14934932df5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

markdown-writing 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 2d 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.

write/skills/markdown-writing/SKILL.md · 193 lines

How it starts

The opening of the file, as written. The whole thing — 193 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Markdown Writing

Two things decide whether Markdown is good: where it renders (which syntax you may use) and how it reads (whether anyone finishes it). Handle them in that order.

This skill writes and edits Markdown files in the working tree, and nothing else — no commits. Edit an existing document with targeted edits to the passages you are changing; never rewrite the whole file. A whole-file rewrite restyles wrap width, emphasis, and heading case that nobody asked to change, and buries the real edit in the diff.

1. Check the render target first

Renders where What you may use
GitHub only — issues, PRs, comments, discussions, wiki, repo file views Everything, including alerts, <details>, task lists, footnotes, mermaid, theme-aware images
README that also ships to npm, PyPI, a docs site, or an editor preview CommonMark + tables + <details>. GitHub extras are degradable, not free: every alert body must read correctly with its [!IMPORTANT] line showing as literal text
Terminal, --help output, plain-text logs No Markdown. Write plain text

What that degradation looks like: on npm a GitHub alert renders as a plain blockquote with a literal [!IMPORTANT] line above the text. Use alerts in a published README anyway — but an alert whose body reads "This one." is meaningless the moment the label stops rendering.

Full syntax and per-host support: references/github-features.md.

2. GitHub alerts

Five types, exact spelling, uppercase, nothing on the label line:

> [!NOTE]
> Highlights information that users should take into account, even when skimming.

> [!TIP]
> Optional information to help a user be more successful.

> [!IMPORTANT]
> Crucial information necessary for users to succeed.

> [!WARNING]
> Critical content demanding immediate user attention due to potential risks.

> [!CAUTION]
> Negative potential consequences of an action.

Picking one:

  • NOTE — a true fact that a skimmer would otherwise miss. No stakes.
  • TIP — an optional shortcut. Deleting it costs nothing.
  • IMPORTANT — they will fail without this. Version floors, required config.
  • WARNING — doing it wrong has consequences. Deprecations, data loss, footguns.
  • CAUTION — the consequence of an action they are about to take.

Read the full file on GitHub · 193 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 2d ago Changed · +24 lines f14934932df5
  2. 6d ago First seen · 169 lines · 67 tokens per session scan A 4117fb59b671

Subscribe to this mod's changes

markdown-writing is a skill published in the GitHub repository edloidas/skills (2 stars, last pushed 3d ago), licensed MIT. It adds 67 tokens to every session and 2,031 once invoked, about $0.0003 per session on Opus 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 2026-08-31.