## Feature request: add KaTeX mhchem extension to the Markdown renderer

[vin130901]

Before submitting your bug report

• I've tried using the "Ask AI" feature on the Continue docs site to see if the docs have an answer
• I'm not able to find a related conversation on GitHub discussions that reports the same bug
• I'm not able to find an open issue that reports the same bug
• I've seen the troubleshooting guide on the Continue Docs

Relevant environment info

- OS: Linux x64 (VS Code Server)
- Continue version: 1.2.22
- IDE version: 1.123.0

Description

Summary
The Continue GUI renderer uses KaTeX but does not load the mhchem contrib extension. As a result, \ce{} and \pu{} commands crash the renderer and cause the response to stop rendering mid-output.

Expected behavior
\ce{H2O}, \ce{Fe^{2+}}, and similar chemical equation syntax should render correctly.

Current behavior
Any response containing \ce{...} or \pu{...} causes the KaTeX parser to throw and the entire message block stops rendering.

Proposed fix
Add a single import in the GUI bundle before KaTeX is first used:

import 'katex/contrib/mhchem';

This is the standard way to enable mhchem — it monkey-patches the katex module globally and requires no API changes. The katex package already ships with this contrib file, so no new dependency is needed.

Use case
Users writing chemistry or physics notes (university level) rely on \ce{} for chemical equations. Without mhchem, they are forced to use \mathrm{H_2O} workarounds that produce inferior typesetting — no automatic spacing around arrows, no charge notation, no state symbols.

References

• KaTeX mhchem contrib: https://github.com/KaTeX/KaTeX/tree/main/contrib/mhchem
• mhchem manual: https://mhchem.github.io/MathJax-mhchem/

To reproduce

No response

Log output

[aaditmehtacoder]

Hi! I’m new to contributing and would like to try working on this as a small first contribution.

I’ll look into where KaTeX is initialized in the GUI markdown renderer and try adding the katex/contrib/mhchem import if that’s the right place for the fix, so commands like \ce{H2O} and \pu{...} render correctly. I’ll test locally and open a small PR if the fix works.

[aaditmehtacoder]

I opened PR #12612 for this. I tested it locally in the VS Code Extension Development Host with \ce{CO2 + C -> 2 CO} and confirmed the block reaction renders correctly without stopping the message render.