fix(gh-body-audit,gh-body-conventions): prescribe math fence for display math

[ultimatile]

Summary

GitHub applies Markdown backslash-escape processing to the content of a $$ block before the math renderer receives it, so a backslash followed by ASCII punctuation reaches the renderer as the punctuation alone. A fenced code block with the math info string passes its content through. gh-body-conventions § Math prescribed $$...$$ for display math, and now prescribes the fence.

Closes #241

Changes

• gh-body-conventions § Math prescribes a fenced code block whose info string is math for display math, and rules out $$...$$.
• The limitations comment in skills/gh-body-audit/body-math-scan.sh states that the scan is line-oriented, so its check for inline math wrapped in a code span misses a code span split across source lines, and does not mention $$...$$.
• metadata.version in .claude-plugin/marketplace.json is 2026.10.2.

Verification

• gh api -X POST /markdown -f mode=gfm on a body whose math fence holds x &= a \, b \\ c \{ d \} inside aligned returned a display <math-renderer> element with \,, \\, \{ and \} intact.
• The same endpoint on a $$ block holding a \\ b \, c \; d \{ e \} \_ f \alpha returned a \ b , c ; d { e } _ f \alpha.
• bash skills/gh-body-audit/test-body-math-scan.sh printed All checks passed.; the script edit is comment-only.
• The pre-commit mdformat hook reported Passed on the edited files.

Notes

• gh-body-audit step 2 dismisses a math-scan hit that sits inside a fenced code block, so it dismisses a \operatorname inside a math fence, although § Math forbids the macro in display math. With $$ display math such a hit was outside any fenced code block and was reported. The step dismisses a hit inside an inline code span the same way, and inline math is written as a code span; gh-body-conventions § Math leaves the reach of its rules unstated #242 covers both cases.
• The math scan does not report $$, so a body that still uses it passes the audit; body-math-scan: report $$ display math #243 tracks that check.
• GitHub hands the renderer three backslashes for a \\ that ends a line inside the fence. The rows still typeset one per line, as seen in a browser on the fence in A complicated math expression is not rendered correctly in pdf jupyter-book/mystmd#1583, whose cases rows each end in \\.

[Copilot]

Copilot review overview

🟢 Approval recommended

The focused documentation correction is consistent with the reported GitHub behavior and repository versioning rules.

Review effort: Balanced
Findings: None

What changed in this PR

Updates GitHub body guidance to prevent display-math backslash corruption.

Changes:

• Prescribes fenced math blocks instead of $$...$$.
• Clarifies the math scanner’s line-oriented limitation.
• Bumps plugin version to 2026.10.2.

File	Description
skills/​gh-body-conventions/​SKILL.md	Updates display-math guidance.
skills/​gh-body-audit/​body-math-scan.sh	Corrects the limitations comment.
.claude-plugin/​marketplace.json	Applies the required version bump.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.