Markdown to HTML Converter

Converts Markdown files to beautifully styled HTML with inline CSS, optimized for WeChat Official Account and other platforms.

User Input Tools

When this skill prompts the user, follow this tool-selection rule (priority order):

1. Prefer built-in user-input tools exposed by the current agent runtime — e.g., AskUserQuestion, request_user_input, clarify, ask_user, or any equivalent.
2. Fallback: if no such tool exists, emit a numbered plain-text message and ask the user to reply with the chosen number/answer for each question.
3. Batching: if the tool supports multiple questions per call, combine all applicable questions into a single call; if only single-question, ask them one at a time in priority order.

Concrete AskUserQuestion references below are examples — substitute the local equivalent in other runtimes.

Script Directory

Agent Execution: Determine this SKILL.md directory as {baseDir}. Resolve ${BUN_X} runtime: if bun installed → bun; if npx available → npx -y bun; else suggest installing bun. Replace {baseDir} and ${BUN_X} with actual values.

Script	Purpose
scripts/main.ts	Main entry point

Preferences (EXTEND.md)

Check EXTEND.md in priority order — the first one found wins:

Priority	Path	Scope
1	.baoyu-skills/baoyu-markdown-to-html/EXTEND.md	Project
2	${XDG_CONFIG_HOME:-$HOME/.config}/baoyu-skills/baoyu-markdown-to-html/EXTEND.md	XDG
3	$HOME/.baoyu-skills/baoyu-markdown-to-html/EXTEND.md	User home

If none found, use defaults.

EXTEND.md supports: default theme, custom CSS variables, code block style, mermaid defaults (mermaid_theme, mermaid_scale, mermaid_background).

Workflow

Step 0: Pre-check (Chinese Content)

Condition: Only execute if input file contains Chinese text.

Detection:

1. Read input markdown file
2. Check if content contains CJK characters (Chinese/Japanese/Korean)
3. If no CJK content → skip to Step 1

Format Suggestion:

If CJK content detected AND baoyu-format-markdown skill is available:

Use AskUserQuestion to ask whether to format first. Formatting can fix:

• Bold markers with punctuation inside causing ** parse failures
• CJK/English spacing issues

If user agrees: Invoke baoyu-format-markdown skill to format the file, then use formatted file as input.

If user declines: Continue with original file.

Step 1: Determine Theme

Theme resolution order (first match wins):

1. User explicitly specified theme (CLI --theme or conversation)
2. EXTEND.md default_theme (this skill's own EXTEND.md, checked in Step 0)
3. baoyu-post-to-wechat EXTEND.md default_theme (cross-skill fallback)
4. If none found → use AskUserQuestion to confirm

Cross-skill EXTEND.md check (only if this skill's EXTEND.md has no default_theme):

Read $HOME/.baoyu-skills/baoyu-post-to-wechat/EXTEND.md if it exists and look for a default_theme: line. Use the value if present; otherwise fall through.

If theme is resolved from EXTEND.md: Use it directly, do NOT ask the user.

If no default found: use AskUserQuestion to confirm a theme from the Themes table below.

Step 1.5: Determine Citation Mode

Default: Off. Do not ask by default.

Enable only if the user explicitly asks for "微信外链转底部引用", "底部引用", "文末引用", or passes --cite.

Behavior when enabled:

• Ordinary external links are rendered with numbered superscripts and collected under a final 引用链接 section.
• https://mp.weixin.qq.com/... links stay as direct links and are not moved to the bottom.
• Bare links where link text equals URL stay inline.

Step 2: Convert

${BUN_X} {baseDir}/scripts/main.ts <markdown_file> --theme <theme> [--cite]

Step 3: Report Result

Display the output path from JSON result. If backup was created, mention it.

Usage

${BUN_X} {baseDir}/scripts/main.ts <markdown_file> [options]

Options:

Option	Description	Default
--theme <name>	Theme name (default, grace, simple, modern)	default
--color <name|hex>	Primary color: preset name or hex value	theme default
--font-family <name>	Font: sans, serif, serif-cjk, mono, or CSS value	theme default
--font-size <N>	Font size: 14px, 15px, 16px, 17px, 18px	16px
--title <title>	Override title from frontmatter
--cite	Convert external links to bottom citations, append 引用链接 section	false (off)
--keep-title	Keep the first heading in content	false (removed)
--mermaid-theme <name>	Mermaid theme: default, forest, dark, neutral, base	default
--mermaid-scale <N>	Mermaid render scale (positive number ≤ 4)	2
--mermaid-width <N>	Mermaid target display width in CSS px; PNG is rendered at width × scale pixels when the diagram is narrower than this	860
--mermaid-bg <value>	Mermaid background: white, transparent, or #hex	white
--no-mermaid	Skip Mermaid PNG rendering; emit <pre class="mermaid"> fallback	false
--help	Show help

Color Presets:

Name	Hex	Label
blue	#0F4C81	Classic Blue
green	#009874	Emerald Green
vermilion	#FA5151	Vibrant Vermilion
yellow	#FECE00	Lemon Yellow
purple	#92617E	Lavender Purple
sky	#55C9EA	Sky Blue
rose	#B76E79	Rose Gold
olive	#556B2F	Olive Green
black	#333333	Graphite Black
gray	#A9A9A9	Smoke Gray
pink	#FFB7C5	Sakura Pink
red	#A93226	China Red
orange	#D97757	Warm Orange (modern default)

Examples:

# Basic conversion (uses default theme, removes first heading)
${BUN_X} {baseDir}/scripts/main.ts article.md

# With specific theme
${BUN_X} {baseDir}/scripts/main.ts article.md --theme grace

# Theme with custom color
${BUN_X} {baseDir}/scripts/main.ts article.md --theme modern --color red

# Enable bottom citations for ordinary external links
${BUN_X} {baseDir}/scripts/main.ts article.md --cite

# Keep the first heading in content
${BUN_X} {baseDir}/scripts/main.ts article.md --keep-title

# Override title
${BUN_X} {baseDir}/scripts/main.ts article.md --title "My Article"

Output

File location: Same directory as input markdown file.

• Input: /path/to/article.md
• Output: /path/to/article.html

Conflict handling: If HTML file already exists, it will be backed up first:

• Backup: /path/to/article.html.bak-YYYYMMDDHHMMSS

JSON output to stdout:

{
  "title": "Article Title",
  "author": "Author Name",
  "summary": "Article summary...",
  "htmlPath": "/path/to/article.html",
  "backupPath": "/path/to/article.html.bak-20260128180000",
  "contentImages": [
    {
      "placeholder": "MDTOHTMLIMGPH_1",
      "localPath": "/path/to/img.png",
      "originalPath": "imgs/image.png"
    }
  ],
  "mermaidImages": [
    {
      "hash": "a1b2c3d4e5f6",
      "localPath": "/path/to/imgs/.mermaid-cache/mermaid-a1b2c3d4e5f6.png",
      "cached": false
    }
  ]
}

Mermaid rendering: Code blocks fenced as ```mermaid are rendered to PNGs via headless Chrome (CDP) and cached at imgs/.mermaid-cache/mermaid-<hash>.png. The cache key includes the code, theme, scale, target width, background, and mermaid version. Add imgs/.mermaid-cache/ to .gitignore if you do not want generated diagrams checked in. Requires Chrome/Chromium/Edge on the system; otherwise the block falls back to <pre class="mermaid">…</pre> and conversion still succeeds.

Themes

Theme	Description
default	Classic - traditional layout, centered title with bottom border, H2 with white text on colored background
grace	Elegant - text shadow, rounded cards, refined blockquotes (by @brzhang)
simple	Minimal - modern minimalist, asymmetric rounded corners, clean whitespace (by @okooo5km)
modern	Modern - large radius, pill-shaped titles, relaxed line height (pair with --color red for traditional red-gold style)

Supported Markdown Features

Feature	Syntax
Headings	# H1 to ###### H6
Bold/Italic	**bold**, *italic*
Code blocks	```lang with syntax highlighting
Inline code	`code`
Tables	GitHub-flavored markdown tables
Images	
Links	[text](url); add --cite to move ordinary external links into bottom references
Blockquotes	> quote
Lists	- unordered, 1. ordered
Alerts	> [!NOTE], > [!WARNING], etc.
Footnotes	[^1] references
Ruby text	`{base
Mermaid	```mermaid blocks rendered to local PNG via headless Chrome (cached under imgs/.mermaid-cache/); falls back to <pre class="mermaid"> if Chrome is unavailable or rendering fails
PlantUML	```plantuml diagrams

Frontmatter

Supports YAML frontmatter for metadata:

---
title: Article Title
author: Author Name
description: Article summary
---

If no title is found, extracts from first H1/H2 heading or uses filename.

Extension Support

Custom configurations via EXTEND.md. See Preferences section for paths and supported options.