Mermaid Fixer

Mermaid Fixer

Repair Mermaid diagrams and Markdown tables in Obsidian notes before they break preview, export, or publishing.

Mermaid Fixer is free, local-only, and does not make network requests.

Why this exists

AIGC tools now generate more Markdown, specs, tables, and diagrams than ever. They are useful, but they still frequently produce Mermaid blocks and Markdown tables that look almost right while failing to render in Obsidian.

Mermaid Fixer turns those repeat fixes into a one-command local Markdown repair workflow. Run it on the current note or scan the whole vault, preview the diff, and apply the safe fixes you want.

flowchart LR
    A[AIGC draft] --> B[Mermaid diagram or Markdown table]
    B --> C{Renders cleanly in Obsidian?}
    C -- Yes --> D[Keep writing]
    C -- No --> E[Run Mermaid Fixer]
    E --> F[Preview diff]
    F --> G[Apply fixes]
    G --> D

Highlights

Fix rules

Mermaid Fixer targets common syntax problems that often appear in AI-generated or hand-edited diagrams and tables.

Mermaid rules

Markdown table rules

Table repair is conservative. Ambiguous rows are left unchanged, and fenced code blocks are never modified by table repair.

Examples

Mermaid diagram repair

AI-generated Mermaid diagrams often fail in a way that looks like this:

```mermaid
graph TD
A[Review AIGC output (Mermaid)] --> B{Score > 10}
subgraph Draft Flow
B --> C[Fix & publish]
end
```

Obsidian may show a Mermaid parse error instead of a diagram:

ERROR ON LINE 3:
A[Review AIGC output (Mermaid)] --> B{Score > 10}
-------------------------------------^
Expecting a valid node label, string, or quoted text.

Run Mermaid Fixer, preview the diff, apply the fix, and the same diagram becomes renderable:

graph TD
A["Review AIGC output (Mermaid)"] --> B{"Score > 10"}
subgraph "Draft Flow"
B --> C["Fix & publish"]
end

Markdown table repair

AI-generated Markdown tables often fail in a quieter way:

| Plan | Success | Time | :--- | :--- | :--- | A | 95% | 30 min | B | 85% | 15 min |

Mermaid Fixer can turn the safe collapsed sequence into a normal Markdown table:

Installation

Mermaid Fixer requires Obsidian 1.1.0 or newer.

Community plugins

After the plugin is accepted into the Obsidian Community directory:

1. Open Obsidian settings.
2. Go to Community plugins.
3. Search for Mermaid Fixer.
4. Install and enable the plugin.

Manual install

1. Download the latest GitHub release.
2. Copy main.js, manifest.json, and styles.css.
3. Place them in .obsidian/plugins/mermaid-fixer/.
4. Reload Obsidian.
5. Enable Mermaid Fixer in Community plugins.

Usage

Open the command palette and run:

• Fix current file
• Fix whole vault

If diff preview is enabled, Mermaid Fixer shows the proposed edits before changing your notes. The current-file command updates the active editor. The whole-vault command scans Markdown files for Mermaid or table issues, shows scan progress, opens a summary, and applies changes only after confirmation.

When no repair is needed, Mermaid Fixer confirms the clean state with:

All Mermaid and table are good.

Settings

Privacy

Mermaid Fixer reads note contents only when you run a repair command. It writes only the notes you explicitly choose to update. Mermaid and table repair both run locally. The plugin does not send vault content off device, does not use telemetry, and does not require an account or API key.

Vault enumeration

Mermaid Fixer calls app.vault.getMarkdownFiles() only when you run the Fix whole vault command. This lets the plugin list Markdown file paths in the current vault so it can scan for Mermaid diagrams and Markdown tables that may need repair. During that command, non-skipped Markdown files are read in memory to detect fix candidates. The scan runs locally, does not make network requests, and does not send file paths or note contents off device. Files are modified only after you review and confirm the proposed changes.

See PRIVACY.md for the full data-flow summary.

Release

See RELEASE.md for the Community submission checklist and GitHub release artifact rules.

Development

npm install
npm test
npm run lint
npm run build
node --check main.js

The plugin uses TypeScript, esbuild, and the Obsidian API. Runtime code does not depend on third-party libraries beyond Obsidian itself.

License

MIT