Fix MathJax in Cloze

An Anki add-on that fixes cloze conflicts where }} inside MathJax (or other cloze text) is interpreted as the end of a cloze deletion.

Cloze Conflict Background

Cloze deletions are terminated with }}. If }} appears inside cloze content, Anki may close the cloze too early.

• Problematic:

{{c1::[$]\frac{foo}{\frac{bar}{baz}}[/$] blah blah blah.}}

• Works (space workaround):

{{c1::[$]\frac{foo}{\frac{bar}{baz} }[/$] blah blah blah.}}

LaTeX math mode ignores extra spaces, so rendering remains the same.

Alternative workaround (for cases where visible spaces matter):

{{c1::[$]\frac{foo}{\frac{bar}{baz}<!-- -->}[/$] blah blah blah.}}

The same idea also helps when :: needs to appear in cloze-deleted text, e.g.:

{{c1::std:<!-- -->:variant::~type~}} in C++ is a {{c2::type-safe union}}

What this add-on does

This add-on applies the space workaround by default:

• Replaces internal }} inside cloze content and hints with } }
• Handles trailing }}} boundary conflicts by rewriting them to safe output
• Preserves nested cloze terminators like {{{c1::c}}}
• Overrides Anki's contenteditable default spacing issue by removing non-breaking spaces   exclusively from MathJax tags to prevent rendering breakage.
• Adds quick actions in the Browser menu bar, Browser right-click context menu, and reviewer context menu
• Includes a Settings tab and a Support tab with QR codes, copy buttons, and a Ko-fi widget

Usage

1. Bulk fix from Browser (menu bar)

1. Open Browse.
2. Select one or more notes.
3. Click Notes → Fix MathJax in Cloze (selected notes).
4. A tooltip shows how many notes and replacements were updated.

2. Bulk fix from Browser (right-click)

1. Open Browse.
2. Select one or more notes.
3. Right-click on the selection.
4. Click Fix MathJax in Cloze (selected notes).
5. A tooltip shows how many notes and replacements were updated.

3. Fix current review note

1. While reviewing a card, right-click.
2. Click Fix MathJax in This Note.
3. The current note is updated immediately.

<img width="2083" height="1188" alt="Screenshot_20260307_232051" src="https://github.com/user-attachments/assets/5852640e-4bcf-4dab-ad47-58b95345969e" /> <img width="2083" height="1188" alt="Screenshot_20260307_232059" src="https://github.com/user-attachments/assets/7f0d622d-c714-4c73-888a-c8a875b9b21a" />

Configuration

Open Tools -> Add-ons -> Fix MathJax in Cloze -> Config.

• Settings tab: update the replacement token used for unsafe internal }}
• Support tab: use the embedded Ko-fi button, QR codes, or copy buttons

config.json:

{
  "replacement": "} }",
  "remove_nbsp_in_mathjax": true
}

• replacement: string used to replace internal }} inside cloze content

• Default: } }

• If invalid (empty, non-string, or contains }}), the add-on falls back to } }

• remove_nbsp_in_mathjax: boolean to enable scrubbing non-breaking spaces   automatically generated by Anki's editor (e.g., from typing double spaces or pasting via web browser). This clears them exclusively inside MathJax blocks to avoid LaTeX compilation failures.

• Default: true

Notes

• The add-on rewrites }} found inside cloze content and at the immediate boundary before cloze termination.
• Malformed cloze starts are left unchanged, and parsing continues so later valid clozes in the same field can still be fixed.
• Development, packaging, and versioning notes live in DEVELOPMENT.md.

Support

If this add-on helps, you can support it from the in-app Support tab or here:

Changelog

2026-04-20

• Added automatic removal of non-breaking spaces   from inside native MathJax limits (\() and (\[) and Anki tags to prevent rendering errors caused by Anki's rich-text editor defaults, configurable via remove_nbsp_in_mathjax option and available natively in the settings UI.

2026-04-05

• Added Fix MathJax in Cloze to the Browser right-click context menu
• Refactored codebase into smaller modules for easier maintenance

2026-03-27

• Added Settings tab with configurable replacement token
• Added Support tab with QR codes, copy buttons, and Ko-fi widget
• Added bump.py and make_ankiaddon.py build/packaging scripts
• Added unit tests

2026-03-11

• Refactored cloze parsing into reusable helpers for clearer nested-cloze handling
• Fixed nested cloze cases like {{c3::\(\sin i_{{{c1::c}}} = ...\)}} so the add-on preserves {{c1::c}} and rewrites the outer brace boundary instead
• Added a regression test for the nested-cloze brace case

2026-03-07

• Added screenshots to README for visual guidance

2026-02-25

• Added handling for trailing }}} cloze-boundary conflicts (for example, {{c1::\\mathbf{0}}} → {{c1::\\mathbf{0} }})
• Confirmed behavior applies to cloze content inside and outside MathJax
• Added internal }} replacement in cloze hints (not just cloze answers)
• Added safety fallback for invalid custom replacement values
• Changed malformed-cloze handling to continue scanning later clozes
• Updated documentation to describe boundary rewrite behavior

2026-02-22

• Initial release
• Core cloze rewriting engine (}} → } })
• Browser menu action for bulk-fixing selected notes
• Reviewer right-click menu action for fixing current note
• Fixed replacement string formatting in config.json
• Fixed formatting issues in cloze handling functions
• Improved README with cloze conflict background and examples