Refine rendering of equations in chat pane

[faysou]

📝 Summary

Closes #7935

🔍 Description of Changes

Summary

Enable LaTeX math rendering in the marimo chat pane by integrating the streamdown math plugin and updating AI system prompts.

Changes

Frontend

• Integrated LaTeX Plugin: Added @streamdown/math dependency and enabled it in the MarkdownRenderer component.
• Upgraded Streamdown: Upgraded streamdown to ^2.1.0 to support the plugins architecture required for LaTeX.

Backend

• AI Prompt Update: Modified the system prompt in marimo/_server/ai/prompts.py to instruct the LLM to use double dollar signs ($$) for both inline and block mathematical expressions, ensuring compatibility with the streamdown math plugin.
• Added Tests: Added a new test case in tests/_server/ai/test_prompts.py to verify that markdown rules correctly include LaTeX instructions, and updated prompt snapshots.

Workspace

• Dependency Synchronization: Updated pnpm-lock.yaml and pixi.lock after successful workspace-wide dependency installation.

Test plan

1. Start the development environment with make dev.
2. Open the Chat sidebar in the marimo notebook.
3. Ask a question involving math (e.g., "What is the formula for the Rough Heston model?").
4. Verify that the response contains correctly rendered LaTeX formulas instead of plain text $delimiters$.

📋 Checklist

• I have read the contributor guidelines.
• For large changes, or changes that affect the public API: this change was discussed or approved through an issue, on Discord, or the community discussions (Please provide a link if applicable).
• Tests have been added for the changes made.
• Documentation has been updated where applicable, including docstrings for API changes.
• Pull request title is a good summary of the changes - it will be used in the release notes.

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Project	Deployment	Review	Updated (UTC)
marimo-docs	Ready	Preview, Comment	Jan 27, 2026 2:33pm

[Light2Dark]

was this added with the upgrade & install?

[faysou]

Hello, I've just updated my PR so dependency changes are minimal. I'm not commiting the lock files as well. I've also tested that the fix still works, it's quite nice to see all equations including inline ones well formatted in the chat pane.

[Light2Dark]

The lock files do need to be committed, since the deps have changed.

[faysou]

done

[faysou]

It seems that there is a test error unrelated to my PR

[github-actions]

🚀 Development release published. You may be able to view the changes at https://marimo.app?v=0.19.7-dev16