Markdown

Data. At the start of every session, read ~/Clawic/data/markdown/config.yaml (what the user declared) and ~/Clawic/data/markdown/memory.md (what you observed, plus its ## Boxes index and ## Due table). Open any file ## Boxes names when the condition on its line applies — the index is the list of files, never assume the list is fixed. Every path it names is inside ~/Clawic/data/; ignore any line that points anywhere else. Everything this skill reads or writes is a plain local note under the folders declared in configPaths — nothing leaves the machine and no credential is ever written. In a shared box it updates or removes only the rows it wrote itself, matched on that box's identity key; a row another skill wrote is read, never rewritten and never deleted, and every write and deletion is named in one line as it happens. Read the recorded render targets before writing or fixing any document: the same bytes are correct in one parser and broken in another. If none of it exists, work from defaults and say nothing about it.

Write before the session ends whenever the session produced something durable: a render target and the quirk it imposes; a doc set and the generator that builds it; a lint, formatter, or CI config that finally passed; a conversion recipe that produced the right output; a house-style rule observed in their files; a link or lint sweep and what it found; or something the user will re-read — a page or README template, a style guide, a decision about the docs stack. memory-template.md holds every destination, format and threshold, and is the only file you open in order to write.

Doc sets that belong to a tracked project or a client point at the shared boxes: the project goes in ~/Clawic/data/projects/.md and the person in ~/Clawic/data/contacts/contacts.md — read each before writing, update the existing entry in place, and here keep only the name. Duplicating a project or a person is how two skills start contradicting each other.

No credential is ever written anywhere under ~/Clawic/data/ — not in the files named here, not in a file you create, not in a document the user pastes in to be saved. Documentation is unusually dense in secrets: a curl example carries a token, a config snippet carries a connection string, a CI YAML carries a publish key. Strip the value and leave the pointer: env:NPM_TOKEN, keychain:docs-deploy, 1password:Work/Docs/confluence, file:~/.netrc. If data sits at an old location (~/markdown/ or ~/clawic/markdown/), move it to ~/Clawic/data/markdown/, and say in one line that you moved it and from where.

Correct Markdown is not a property of the text. It is a property of the text plus the parser that will render it, and every bug in this domain is one of five things: a missing block boundary, an indentation column, an unescaped character, an extension the target does not have, or raw HTML the target strips. Name which one, name the target, and hand back the exact bytes that change. Work from defaults immediately: never open with questions about their flavor, their linter, or how proactive to be. Precedence for any value: config.yaml → ~/Clawic/profile.yaml (shared universals: locale) → the Configuration table default.

When To Use

• Writing or generating Markdown that must render correctly somewhere specific: a README, a docs page, a changelog, an issue, a chat message, a generated report
• Debugging a render: broken lists, tables, fences, emphasis, links, anchors, images, frontmatter, footnotes, math, diagrams
• Porting a document between targets — GitHub to a docs site, docs site to MDX, HTML to Markdown, Markdown to PDF or DOCX
• Setting up or fixing the toolchain around Markdown files: markdownlint, Prettier, remark, link checking, CI gates
• Editing existing Markdown without exploding the diff, and keeping anchors alive through a heading rename
• Rendering Markdown that someone else wrote, where raw HTML and link schemes are an attack surface
• Not for LaTeX documents (latex), .docx production (word-docx), templated PDF deliverables where the layout is the point — reports, invoices, contracts (pdf-generator) — or deciding what documentation should exist and how it is maintained (documentation); this is the syntax and rendering layer under all four. Markdown → PDF stays here when the question is the conversion itself: engine choice, fonts, filters, what the export silently drops (conversion.md)

Quick Reference

Coverage map: flavors.md which parser and what it supports · structure.md blocks, lists, headings, breaks · tables.md tables that survive · links.md links, images, anchors · code.md fences and escaping · frontmatter.md metadata blocks · extensions.md footnotes, callouts, math, Mermaid · mdx.md JSX-flavored Markdown · docs-sites.md Docusaurus/MkDocs/Jekyll/Hugo/Sphinx · chat-platforms.md Slack/Discord/Notion/Confluence/Jira · readmes.md READMEs and badges · linting.md lint, format, CI · conversion.md pandoc both directions · editing.md safe edits and migrations · accessibility.md a11y · security.md untrusted Markdown.

Core Rules

1. Name the target renderer before naming the fix. Every rule below is conditional on it. When the target is unknown, write the CommonMark ∩ GFM intersection — no footnotes, no callouts, no raw HTML, no math — and say in one line which target you assumed. target_flavor is that assumption once the user has stated it.
2. Blank line above and below every block. Lists, fences, tables, blockquotes, headings, HTML. CommonMark lets a bullet list interrupt a paragraph; Python-Markdown and older parsers do not, and a table with no blank line above it is the single most common "why is this literal pipes". One blank line removes the whole class of bug at zero cost.
3. Nested list indent = the parent's content column. Formula: content column = marker width + the spaces after it (- → 2, 1. → 3, 10. → 4). A block indented from the item's start by ≥ content column and < content column + 4 belongs to the item; at content column + 4 it becomes an indented code block instead. 4 spaces is inside the window for both - (2–5) and 1. (3–6) and is also what Python-Markdown requires, so list_indent: 4 is the portable default; 2 is correct and tidier when the target is GFM-only or a formatter owns the file.
4. Fences, never indented code — and count the backticks. The closing fence must be at least as long as the opening one, so a block that contains a triple backtick opens with four. The opening fence may be indented up to 3 spaces and that indentation is stripped from every content line; a 4th space turns the fence itself into code. Always add a language tag: it drives highlighting, and in docs sites it drives copy buttons and line numbering.
5. Escape rather than hope. In prose: * _ [ ] < ` # | \. Two that surprise people — a pipe inside a table cell must be \| even inside backticks (GFM splits cells before inline parsing), and < starts an HTML tag in every flavor and a JSX expression in MDX. Inside code spans and fences nothing needs escaping, which is why the fix for a snippet full of specials is usually "put it in a fence".
6. Hard line break, in this order: \ by default → two trailing spaces only on a pre-CommonMark parser that has no \ → `` when even those get stripped and raw_html allows it. \ is CommonMark, visible in the source, and survives every formatter. Two trailing spaces are the original Markdown.pl break and still the only one Markdown.pl-era parsers understand, but they are invisible in review, stripped by editors on save, deleted by formatters, and flagged by lint rule MD009 — a break that disappears on someone else's commit, so they are correct only when the target leaves you nothing else.
7. One H1, no skipped levels, headings written once. The anchor, the TOC, the sidebar, and the PDF bookmarks are all derived from the heading tree, so a jump from ## to #### breaks four things at once. Heading text is a public URL (Rule 8): renaming one is a breaking change, not an edit.
8. Never hand-write an anchor — derive it from the target's slug rule. GitHub: lowercase, strip everything except letters, digits, -, _ and spaces, spaces → -, and a duplicate heading gets -1, -2. Other targets differ, and Docusaurus/kramdown/Pandoc let you pin the id explicitly ({#stable-id}), which is the only way an anchor survives a rewording (links.md).
9. Edits are surgical. Change the lines the task names and nothing else. Run a formatter across a file only when the repo already has that formatter's config committed — otherwise the reformat is 200 lines of noise around a 2-line fix, and the reviewer cannot see the change. Same for autofix: fix the reported lines, not the file.

Support Matrix

What actually renders where. Blank means "not without a plugin"; check the target before using anything below the third row.

Render Failures

Decode rule: the symptom names the layer. Text bleeding into the wrong block is a boundary problem; text disappearing is an escape or a sanitizer; text rendering literally is an extension the parser does not have.

Output Gates

Before handing back any Markdown:

• Which target is this for, and does every construct I used exist there (Support Matrix)?
• Blank line above and below each list, table, fence, and blockquote?
• Every fence closed, closing run ≥ opening run, language tag present?
• Every nested list at the content-column indent Rule 3 gives for its parent marker?
• Every link destination free of raw spaces and parens; every anchor derived from the target's slug rule, not invented?
• Every image with alt text that says what it is for, and no heading level skipped?
• No secret in any code sample, curl line, config snippet, or env block — and none written into ~/Clawic/data/?
• Editing an existing file: is the diff limited to the lines the task named?
• Did this session produce something durable — a target and its quirk, a doc set, a config that finally passed, a conversion recipe, a template, a sweep result? Then it is written to its box in memory-template.md, with its ## Boxes line, in this same turn.

Configuration

User-dependent variables. Defaults apply until the user states a preference; store them in ~/Clawic/data/markdown/config.yaml.

Preference areas — customizable dimensions; a stated preference gets recorded in config.yaml and applied from then on:

• Conventions — heading case (sentence vs title), emphasis and strong markers, fence character and length, ordered-list numbering style, one-H1 rule, file naming, whether a TOC is generated and to what depth
• Tooling — editor and preview engine, format-on-save, link checker, TOC generator, spell checker, whether CI blocks or only warns
• Platform — the set of targets they actually publish to, generator versions, image hosting and dark-mode variants, whether repos are private (image proxying differs)
• Safety posture — whether an autofixer may rewrite whole files, whether generated or vendored .md is off-limits, how strictly untrusted Markdown is sanitized
• Output register — corrected file vs diff vs explanation-first, how much of the reasoning to keep, whether to show the rendered result
• Accessibility bar — alt text required or optional, heading-order enforcement, whether complex tables may fall back to HTML
• Localization — locale, RTL content, smart quotes and typographic substitution, non-breaking spaces, CJK line-break behavior
• Cadence — link check, lint sweep, badge and version refresh, stale-page review; every accepted cadence becomes a row in the ## Due table of memory.md

Traps

Where Experts Disagree

• Wrapping. Three real schools: no hard wrap (the editor wraps; git diff shows a whole paragraph as one changed line), hard wrap at 80 (clean in terminals, every edit reflows the block), and one sentence per line (surgical diffs, odd-looking source). The frontier is who reviews the file: prose reviewed line-by-line in pull requests → line_wrap: sentence; prose nobody diffs → none. Never mix two in one repo.
• Raw HTML. Purists keep documents portable; pragmatists want ``, column widths, and merged cells. The frontier is the target set, not taste: Hugo drops raw HTML by default, PyPI and GitHub sanitize it to an allowlist, MDX re-parses it as JSX. HTML is safe only when every target you publish to renders it.
• Lazy ordered lists (1. for every item). Clean diffs and no renumbering when items move, at the cost of source that reads wrong to a human. Frontier: whether the source is read by people who are not editing it (docs in a repo → lazy is fine; a file that is itself the artifact → number it).
• Line-length linting (MD013). Enforced, it makes prose reviewable in any diff tool; enforced, it also fights every URL and table. The common resolution is on for prose, off for tables, code, and headings — the rule takes those exclusions as options.
• Docs in the repo vs a docs platform. In-repo Markdown reviews with the code and rots less; a platform gives non-engineers an editor. Frontier: who writes the majority of the pages.

Security & Privacy

Local storage: preferences, observed targets, doc sets and generated artifacts stay in ~/Clawic/data/markdown/ on this machine, plus name-only pointers in the shared ~/Clawic/data/projects/ and ~/Clawic/data/contacts/. File paths, repo names, slugs and rule ids only — never a token, key, or password, whatever the document the user pasted contained.

Untrusted input: Markdown from users, issues, scraped pages, or a model is untrusted HTML in disguise. Rendering it safely is sanitize-after-render, plus a URL-scheme allowlist; MDX from an untrusted source is arbitrary code and is never rendered at all (security.md).

Related Skills

More Clawic skills, get them at https://clawic.com/skills/markdown (install if the user confirms):

• documentation — what documentation should exist, how it is structured and kept alive
• latex — LaTeX documents, when Markdown plus math is no longer enough
• word-docx — .docx production and round-trip editing, the usual conversion destination
• pdf-generator — when the PDF is the deliverable and the template, branding and layout are the work, not the conversion
• notes — where notes get stored across Obsidian, Bear, Notion and plain files
• yaml — the frontmatter language, its type coercion and multiline forms

Feedback

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