[Bug] LaTeX math corrupted by markdown escaping and not rendered in terminal output

I built an opt-in MessageDisplay plugin that preserves Markdown-sensitive LaTeX escapes in Claude Code terminal output:

• Repository: https://github.com/iCodeCraft/claude-code-latex-terminal
• Release: https://github.com/iCodeCraft/claude-code-latex-terminal/releases/tag/v0.1.0

It preserves commands such as \,, \;, \:, \!, and \\ in dollar-delimited LaTeX, so the source remains copyable. The transformation is display-only: it does not modify the transcript or model context, and it makes no network requests.

I verified the workaround end-to-end with Claude Code 2.1.220 on macOS/Kitty. The automated test suite also runs on macOS, Linux, and Windows with Git Bash. I have submitted the plugin to the Claude Code community marketplace for review.

This is a source-preservation workaround, not visual equation rendering; a built-in rendering or source-preservation fix would still be preferable. Feedback from a Windows/WezTerm setup would be especially valuable.

While implementing this workaround, I found that the bundled Hook Development skill did not cover the MessageDisplay event or its streaming semantics. I opened a separate documentation PR to address that gap: https://github.com/anthropics/claude-code/pull/83374

Follow-up: I've since published mathshow, which takes a different angle on the same pain. The MessageDisplay plugin here preserves LaTeX-sensitive escapes in Claude Code's terminal output — still valuable for copy/paste fidelity. mathshow is agent-agnostic: when the user should see a formula, the agent runs:

npx --yes mathshow -- '<latex>'

→ KaTeX preview in the browser. Works with Cursor, Claude Code, Codex, and other agents via the Agent Skills format.

https://github.com/iCodeCraft/mathshow Still not a substitute for fixing markdown escaping at the TUI layer (this issue), but it sidesteps the rendering gap entirely. If you're on Windows/WezTerm, I'd love to know whether the plugin + mathshow combo covers your workflow.

Adding evidence from the other side of the pipe. I maintain a terminal that typesets $…$ / $$…$$ in command output, so I see exactly which bytes Claude Code writes, twice: once while the answer streams, and once when the finished answer is redrawn through the markdown renderer. The streamed bytes are intact; the final redraw is where the LaTeX is changed. Beyond the spacing macros in the report above, three more rules bite:

1. \\ → \. Every row separator inside pmatrix / aligned / cases loses one backslash, so a matrix that was valid a second earlier ends up with a stray \ at each line end and cannot be parsed by any TeX engine.
2. \[ → [ and \] → ]. A display block delimited with brackets loses both delimiters.
3. A line holding only = (an A x = b written across three lines of matrices) is taken as a setext underline: the paragraph above it becomes an H1 and the = line is deleted from the output. The equation then reads A x b.

Minimal reproduction (ask for exactly this, then compare the streamed text with the final redraw):

$$
\begin{pmatrix} a & b \\ c & d \end{pmatrix}
\begin{pmatrix} x \\ y \end{pmatrix}
=
\begin{pmatrix} ax + by \\ cx + dy \end{pmatrix}
$$

Final redraw as received by the terminal: the \\ become \, and the = line is gone with the lines above it styled as a heading.

Suggested fix, in order of cost: mask $…$, $$…$$, \(…\) and \[…\] spans before the CommonMark pass and restore them verbatim afterwards (this is what GitHub's renderer does, and what the Codex TUI started doing this week in openai/codex#45501 and openai/codex#45612, with a verbatim fallback for anything it cannot render). Rendering the math is optional; not altering it is the part that matters, because the bytes in the terminal are what gets copied, and what a terminal that can typeset them is given.

Observed with Claude Code 2.1.274 on Windows 11, in Folio (the terminal I maintain); the bytes are the same in any terminal, since the change happens before they are written.