A writing guide for creating richly formatted HackMD notes. HackMD is a collaborative online Markdown editor with extra features such as callouts, diagrams, embeds, and mathematical notation.

Use it to draft HackMD notes with headings, tables, alerts, highlights, tags, diagrams, media embeds, or formulas when appropriate.

It helps choose suitable HackMD formatting instead of relying only on basic Markdown. The guide also keeps longer notes structured and easy to scan.

hackmd-note — Skill for Claude Code and Codex by unbias38

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 unbias38/my-claude-skills --skill hackmd-note

Clone the repo

git clone --depth 1 https://github.com/unbias38/my-claude-skills

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/unbias38/my-claude-skills/hackmd-note/github.svg)](https://agentmods.dev/skills/unbias38/my-claude-skills/hackmd-note)

Your own site

<a href="https://agentmods.dev/skills/unbias38/my-claude-skills/hackmd-note"><img src="https://agentmods.dev/badge/skills/unbias38/my-claude-skills/hackmd-note/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/unbias38/my-claude-skills/hackmd-note"><img src="https://agentmods.dev/badge/skills/unbias38/my-claude-skills/hackmd-note.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 142 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 827 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 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.

Model	Per session	Once invoked
Fable 5.1	$0.00142	$0.00827
Opus 5	$0.00071	$0.00413
Sonnet 5	$0.00028	$0.00165
Haiku 4.5	$0.00014	$0.00083

Measured 12d ago against content hash c18440d48037, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

hackmd-note 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 12d 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.

hackmd-note/SKILL.md · 49 lines

How it starts

The opening of the file, as written. The whole thing — 49 lines — stays where its author put it; the contents beside it link to each section on GitHub.

HackMD Note Writer

Write information-rich HackMD notes that make full use of HackMD's extended Markdown syntax.

Before Writing

Read references/syntax-core.md for the core HackMD syntax. Read references/syntax-advanced.md ONLY when the note needs diagrams (mermaid/graphviz/sequence/flow/markmap/vega), music notation, a slide deck, or book mode.

Writing Guidelines

Use the right feature for the job. Pick syntax that enhances readability:
- :::info / :::warning / :::danger / :::success for callouts
- :::spoiler for supplementary details the reader can expand
- > [!TIP] / > [!NOTE] / > [!IMPORTANT] for inline alerts
- ==highlight== for key terms, ++underline++ for emphasis
- Tables for structured comparisons
- [TOC] when the note has 4+ sections
- Mermaid / flow / sequence / graphviz diagrams when visualizing processes or relationships
- MathJax when formulas appear
- {%youtube ID %} / {%pdf URL %} / {%figma URL %} for embeds
Structure clearly. Use headings (##–####), horizontal rules (---), and tags (###### tags: `tag`). Lead with a brief summary or context block.
Keep it scannable. Combine prose paragraphs with bullet lists, tables, and diagrams. Avoid walls of text.
Respect the output mode. If the user asks for a slide deck, use --- / ---- separators and slideOptions YAML. If they ask for a book, use === / --- with list-of-links structure.
Language. Match the user's language. Default to Traditional Chinese (繁體中文) if the user writes in Chinese.
Output format. Produce the note as one copy-pasteable block. Because the note itself usually contains ``` fences (mermaid, code samples), wrap it in a four-backtick fence (markdown ... ), never a three-backtick one.

範圍邊界

本 skill 只負責產出筆記內容（Markdown 文字），保持無副作用。以下不在範圍：

發表／上傳：不呼叫 HackMD API 或 mcp__hackmd__* 工具。若使用者要求「發表」且環境有發表用 skill 或 MCP 工具，先用本 skill 完成草稿，再交給該工具/工作流。
既有筆記管理：不列出、更新、刪除使用者的 HackMD 筆記。

Read the full file on GitHub · 49 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.

12d ago First seen · 49 lines · 142 tokens per session scan A c18440d48037

Subscribe to this mod's changes

hackmd-note is a skill published in the GitHub repository unbias38/my-claude-skills (2 stars, last pushed 17d ago), licensed MIT. It adds 142 tokens to every session and 827 once invoked, about $0.0007 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.

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