Agent Skills: Obsidian Plugin Development Guidelines

Obsidian Plugin Development Guidelines

Follow these comprehensive guidelines derived from the official Obsidian ESLint plugin rules, submission requirements, and best practices.

Getting Started

Quick Start Tool

For new plugin projects, an interactive boilerplate generator is available:

• Script: tools/create-plugin.js in the skill repository
• Command: Invoke create-plugin using your agent's method (/create-plugin, $create-plugin, or @create-plugin)
• Generates minimal, best-practice boilerplate with no sample code
• Detects existing projects and only adds missing files

Recommend the boilerplate generator when users ask how to create a new plugin, want to start a new project, or need help setting up the basic structure.

Rules Reference (eslint-plugin-obsidianmd v0.1.9)

Submission & Naming

| # | Rule | ✅ Do | ❌ Don't | |---|------|--------|----------| | 1 | Plugin ID | Omit "obsidian"; don't end with "plugin" | Include "obsidian" or end with "plugin" | | 2 | Plugin name | Omit "Obsidian"; don't end with "Plugin" | Include "Obsidian" or end with "Plugin" | | 3 | Plugin name | Don't start with "Obsi" or end with "dian" | Start with "Obsi" or end with "dian" | | 4 | Description | Omit "Obsidian", "This plugin", etc. | Use "Obsidian" or "This plugin" | | 5 | Description | End with .?!) punctuation | Leave description without terminal punctuation |

Memory & Lifecycle

| # | Rule | ✅ Do | ❌ Don't | |---|------|--------|----------| | 6 | Event cleanup | Use registerEvent() for automatic cleanup | Register events without cleanup | | 7 | View references | Return views/components directly | Store view references in plugin properties or pass plugin as component to MarkdownRenderer |

Type Safety

| # | Rule | ✅ Do | ❌ Don't | |---|------|--------|----------| | 8 | TFile/TFolder | Use instanceof for type checking | Cast to TFile/TFolder; use any; use var |

UI/UX

| # | Rule | ✅ Do | ❌ Don't | |---|------|--------|----------| | 9 | UI text | Sentence case — "Advanced settings" | Title Case — "Advanced Settings" | | 10 | JSON locale | Sentence case in JSON locale files (recommendedWithLocalesEn) | Title case in locale JSON | | 11 | TS/JS locale | Sentence case in TS/JS locale modules | Title case in locale modules | | 12 | Command names | Omit "command" in command names/IDs | Include "command" in names/IDs | | 13 | Command IDs | Omit plugin ID/name from command IDs/names | Duplicate plugin ID in command IDs | | 14 | Hotkeys | No default hotkeys | Set default hotkeys | | 15 | Settings headings | Use .setHeading() | Create manual HTML headings; use "General", "settings", or plugin name in headings |

API Best Practices

| # | Rule | ✅ Do | ❌ Don't | |---|------|--------|----------| | 16 | Active file edits | Use Editor API | Use Vault.modify() for active file edits | | 17 | Background file mods | Use Vault.process() | Use Vault.modify() for background modifications | | 18 | User paths | Use normalizePath() | Hardcode .obsidian path; use raw user paths | | 19 | OS detection | Use Platform API | Use navigator.platform/userAgent | | 20 | Network requests | Use requestUrl() | Use fetch() | | 21 | Logging | Minimize console logging; none in onload/onunload in production | Use console.log in onload/onunload |

Styling

| # | Rule | ✅ Do | ❌ Don't | |---|------|--------|----------| | 22 | CSS variables | Use Obsidian CSS variables for all styling | Hardcode colors, sizes, or spacing | | 23 | CSS scope | Scope CSS to plugin containers | Use broad CSS selectors | | 24 | Style elements | Use styles.css file (no-forbidden-elements) | Create <link> or <style> elements; assign styles via JavaScript |

Accessibility (MANDATORY)

| # | Rule | ✅ Do | ❌ Don't | |---|------|--------|----------| | 25 | Keyboard access | Make all interactive elements keyboard accessible; Tab through all elements | Create inaccessible interactive elements | | 26 | ARIA labels | Provide ARIA labels for icon buttons; use data-tooltip-position for tooltips | Use icon buttons without ARIA labels | | 27 | Focus indicators | Use :focus-visible with Obsidian CSS variables; touch targets ≥ 44×44px | Remove focus indicators; make touch targets < 44×44px |

Security & Compatibility

| Rule | ✅ Do | ❌ Don't | |------|--------|----------| | DOM safety | Use Obsidian DOM helpers (createDiv(), createSpan(), createEl()) | Use innerHTML/outerHTML or document.createElement | | iOS compat | Avoid regex lookbehind (iOS < 16.4 incompatibility) | Use regex lookbehind |

Code Quality

| Rule | ✅ Do | ❌ Don't | |------|--------|----------| | Sample code | Remove all sample/template code | Keep class names like MyPlugin, SampleModal | | Object.assign | Object.assign({}, defaults, overrides) (object-assign) | Object.assign(defaultsVar, other) — mutates defaults | | LICENSE | Copyright holder must not be "Dynalist Inc."; year must be current (validate-license) | Leave "Dynalist Inc." as holder or use an outdated year | | Async | Use async/await | Use Promise chains |

Detailed Guidelines

For comprehensive information on specific topics, see the reference files:

Memory Management & Lifecycle

• Using registerEvent(), addCommand(), registerDomEvent(), registerInterval()
• Avoiding view references in plugin
• Not using plugin as component
• Proper leaf cleanup

Type Safety

• Using instanceof instead of type casting
• Avoiding any type
• Using const and let over var

UI/UX Standards

• Sentence case enforcement (TypeScript, JSON locale, TS/JS locale modules)
• recommendedWithLocalesEn config for locale file checks
• Command naming conventions (no "command", no plugin name, no plugin ID)
• Settings and configuration best practices

File & Vault Operations

• View access patterns
• Editor vs Vault API
• Atomic file operations
• File management
• Path handling

CSS Styling Best Practices

• Avoiding inline styles
• Using Obsidian CSS variables
• Scoping plugin styles
• Theme support
• Spacing and layout

Accessibility (A11y)

• Keyboard navigation (MANDATORY)
• ARIA labels and roles (MANDATORY)
• Tooltips and accessibility
• Focus management (MANDATORY)
• Focus visible styles (MANDATORY)
• Screen reader support (MANDATORY)
• Mobile and touch accessibility (MANDATORY)
• Accessibility checklist

Code Quality & Best Practices

• Removing sample code
• Security best practices
• Platform compatibility
• API usage best practices
• Async/await patterns
• DOM helpers

Plugin Submission Requirements

• Repository structure
• Submission process
• Semantic versioning
• Testing checklist
• Additional resources and important notes

Plugin Submission Validation Workflow

Before submitting a plugin, follow this sequence:

1. Run ESLint — npx eslint . using eslint-plugin-obsidianmd; fix all errors (warnings are informational)
2. Validate manifest — Confirm id, name, description, version, and minAppVersion meet naming and formatting rules (rules 1–5)
3. Check LICENSE — Copyright holder must not be "Dynalist Inc." and the year must be current
4. Test on mobile — Verify no regex lookbehind, no fetch(), and touch targets ≥ 44×44px (skip only if plugin is declared desktop-only)
5. Keyboard accessibility audit — Tab through all interactive elements; confirm focus indicators and ARIA labels are present
6. Submit — Open a PR to the community plugins repository with the updated manifest.json and community-plugins.json entry

If ESLint reports new errors after fixing, re-run from step 1.

When Reviewing/Writing Code

Use this checklist for code review and implementation:

1. Memory management: Are components and views properly managed?
2. Type safety: Using instanceof instead of casts?
3. UI text: Is everything in sentence case?
4. Command naming: No redundant words?
5. File operations: Using preferred APIs?
6. Mobile compatibility: No iOS-incompatible features?
7. Sample code: Removed all boilerplate?
8. Manifest: Correct version, valid structure?
9. Accessibility: Keyboard navigation, ARIA labels, focus indicators?
10. Testing: Can you use the plugin without a mouse?
11. Touch targets: Are all interactive elements at least 44×44px?
12. Focus styles: Using :focus-visible and proper CSS variables?

Common Patterns

Proper Command Registration

// ✅ CORRECT
this.addCommand({
  id: 'insert-timestamp',
  name: 'Insert timestamp',
  editorCallback: (editor: Editor, view: MarkdownView) => {
    editor.replaceSelection(new Date().toISOString());
  }
});

Safe Type Narrowing

// ✅ CORRECT
const file = this.app.vault.getAbstractFileByPath(path);
if (file instanceof TFile) {
  // TypeScript now knows it's a TFile
  await this.app.vault.read(file);
}

Keyboard Accessible Button

// ✅ CORRECT
const button = containerEl.createEl('button', {
  attr: {
    'aria-label': 'Open settings',
    'data-tooltip-position': 'top'
  }
});
button.setText('⚙️');

button.addEventListener('keydown', (e) => {
  if (e.key === 'Enter' || e.key === ' ') {
    e.preventDefault();
    performAction();
  }
});

Themed CSS

/* ✅ CORRECT */
.my-plugin-modal {
  background: var(--modal-background);
  color: var(--text-normal);
  padding: var(--size-4-4);
  border-radius: var(--radius-m);
  font-size: var(--font-ui-medium);
}

.my-plugin-button:focus-visible {
  outline: 2px solid var(--interactive-accent);
  outline-offset: 2px;
}

When helping with Obsidian plugin development, proactively apply these rules and suggest improvements based on these guidelines. Refer to the detailed reference files for comprehensive information on specific topics.