Allenhutchison Obsidian Gemini Obsidian Plugin Development

Obsidian Plugin Development

When to use this skill

Use this skill when:

• Creating or modifying an Obsidian plugin
• Working with the obsidian npm package TypeScript API
• Building plugin UI: views, modals, settings tabs, commands, ribbon icons, context menus, status bar
• Performing vault file operations (read, create, modify, delete, rename)
• Manipulating the editor (cursor, selection, transactions)
• Working with the workspace (leaves, tabs, splits, sidebars)
• Using MetadataCache for frontmatter, links, tags, headings
• Handling events (vault, workspace, editor, metadata changes)
• Rendering markdown programmatically
• Making HTTP requests from a plugin (use requestUrl, not fetch)
• Using the Obsidian CLI for automation, scripting, or developer tooling
• Debugging or testing an Obsidian plugin

Plugin anatomy

An Obsidian plugin consists of:

my-plugin/
  ├── main.ts          # Entry point: default export extending Plugin
  ├── manifest.json    # Plugin metadata (id, name, version, minAppVersion)
  ├── styles.css       # Optional: plugin styles
  ├── package.json     # npm dependencies
  ├── tsconfig.json    # TypeScript config
  └── esbuild.config.mjs  # Build config (or rollup/vite)

manifest.json

{
	"id": "my-plugin",
	"name": "My Plugin",
	"version": "1.0.0",
	"minAppVersion": "1.0.0",
	"description": "Description of plugin",
	"author": "Author Name",
	"authorUrl": "https://example.com",
	"isDesktopOnly": false
}

Main plugin class

import { Plugin } from 'obsidian';

export default class MyPlugin extends Plugin {
	settings: MySettings;

	async onload() {
		// Called when plugin is activated
		await this.loadSettings();
		this.addSettingTab(new MySettingTab(this.app, this));
		this.addCommand({ id: 'my-cmd', name: 'My Command', callback: () => {} });
		this.addRibbonIcon('icon-name', 'Tooltip', () => {});
		this.registerView('view-type', (leaf) => new MyView(leaf));
		this.registerEvent(this.app.vault.on('modify', (file) => {}));
	}

	onunload() {
		// Called when plugin is deactivated - cleanup happens automatically
		// for anything registered via this.register*() or this.add*()
	}

	async loadSettings() {
		this.settings = Object.assign({}, DEFAULT_SETTINGS, await this.loadData());
	}

	async saveSettings() {
		await this.saveData(this.settings);
	}
}

Core API classes

The app object (available as this.app in Plugin subclasses) provides access to the entire API:

Vault - File operations

// Read
const content = await this.app.vault.read(file); // async read
const cached = await this.app.vault.cachedRead(file); // faster, may be stale

// Create
const newFile = await this.app.vault.create('path/file.md', 'content');
await this.app.vault.createFolder('path/folder');

// Modify
await this.app.vault.modify(file, 'new content');
await this.app.vault.append(file, '\nappended text');

// Atomic read-modify-write
await this.app.vault.process(file, (data) => {
	return data.replace('old', 'new');
});

// Delete and rename
await this.app.vault.delete(file);
await this.app.vault.trash(file, true); // system trash
await this.app.vault.rename(file, 'new/path.md');

// Find files
const file = this.app.vault.getAbstractFileByPath('notes/note.md');
if (file instanceof TFile) {
	/* use it */
}
const allMd = this.app.vault.getMarkdownFiles();
const allFiles = this.app.vault.getFiles();

IMPORTANT: Always use vault.getAbstractFileByPath() and check instanceof TFile/TFolder. Never construct TFile/TFolder objects directly.

Workspace - Views, leaves, layout

// Get active editor/file
const view = this.app.workspace.getActiveViewOfType(MarkdownView);
const file = this.app.workspace.getActiveFile();

// Open files
const leaf = this.app.workspace.getLeaf('tab'); // 'tab' | 'split' | 'window'
await leaf.openFile(file);
await this.app.workspace.openLinkText('Note Name', '', true);

// Find views
const leaves = this.app.workspace.getLeavesOfType('my-view');
this.app.workspace.iterateAllLeaves((leaf) => {
	/* ... */
});

// Sidebar leaves
const rightLeaf = this.app.workspace.getRightLeaf(false);

// Layout readiness
this.app.workspace.onLayoutReady(() => {
	/* safe to access UI */
});

MetadataCache - Parsed file metadata

const cache = this.app.metadataCache.getFileCache(file);
if (cache) {
	cache.headings; // HeadingCache[]
	cache.tags; // TagCache[]
	cache.links; // LinkCache[]
	cache.embeds; // EmbedCache[]
	cache.frontmatter; // FrontMatterCache
	cache.sections; // SectionCache[]
}

// Resolve a wikilink to a TFile
const target = this.app.metadataCache.getFirstLinkpathDest('Note', 'source/path.md');

FileManager - High-level file operations

// Process frontmatter (atomic read-modify-write for YAML)
await this.app.fileManager.processFrontMatter(file, (fm) => {
	fm.tags = ['tag1', 'tag2'];
	fm.modified = new Date().toISOString();
});

// Rename with metadata updates (updates links across vault)
await this.app.fileManager.renameFile(file, 'new/path.md');

Editor - Text manipulation

const view = this.app.workspace.getActiveViewOfType(MarkdownView);
if (view) {
	const editor = view.editor;

	// Cursor and selection
	const cursor = editor.getCursor(); // { line, ch }
	const selection = editor.getSelection();
	editor.replaceSelection('replacement');
	editor.setSelection(anchor, head);

	// Content
	const value = editor.getValue();
	const line = editor.getLine(lineNum);
	editor.replaceRange('text', from, to);

	// Batch operations
	editor.transaction({ changes: [{ from, to, text: 'new' }] });

	// Scroll
	editor.scrollIntoView({ from, to }, true);
}

UI components

Commands

this.addCommand({
	id: 'unique-command-id',
	name: 'Human-readable name',
	callback: () => {
		/* runs always */
	},
	// OR for editor commands:
	editorCallback: (editor: Editor, view: MarkdownView) => {
		/* runs when editor active */
	},
	// OR conditional:
	checkCallback: (checking: boolean) => {
		if (canRun) {
			if (!checking) {
				doStuff();
			}
			return true;
		}
		return false;
	},
	hotkeys: [{ modifiers: ['Mod', 'Shift'], key: 'p' }],
});

Modals

class MyModal extends Modal {
	constructor(app: App) {
		super(app);
	}

	onOpen() {
		this.setTitle('My Modal');
		this.contentEl.createEl('p', { text: 'Content here' });
		new Setting(this.contentEl).setName('Option').addToggle((t) => t.setValue(true).onChange((v) => {}));
	}

	onClose() {
		this.contentEl.empty();
	}
}

// Usage: new MyModal(this.app).open();

Settings tabs

class MySettingTab extends PluginSettingTab {
	plugin: MyPlugin;
	constructor(app: App, plugin: MyPlugin) {
		super(app, plugin);
		this.plugin = plugin;
	}

	display() {
		const { containerEl } = this;
		containerEl.empty();

		new Setting(containerEl)
			.setName('Setting name')
			.setDesc('Description')
			.addText((text) =>
				text
					.setPlaceholder('placeholder')
					.setValue(this.plugin.settings.value)
					.onChange(async (v) => {
						this.plugin.settings.value = v;
						await this.plugin.saveSettings();
					})
			);

		// Setting control types: addText, addTextArea, addToggle, addDropdown,
		// addSlider, addButton, addExtraButton, addColorPicker, addSearch
	}
}

Custom views

class MyView extends ItemView {
  getViewType() { return 'my-view-type'; }
  getDisplayText() { return 'My View'; }
  getIcon() { return 'bot'; }

  async onOpen() {
    const container = this.containerEl.children[1];
    container.empty();
    container.createEl('h4', { text: 'My View' });
    this.addAction('refresh-cw', 'Refresh', () => { /* header action */ });
  }

  async onClose() { /* cleanup */ }
}

// Register in onload:
this.registerView('my-view-type', (leaf) => new MyView(leaf));

// Activate:
async activateView() {
  let leaf = this.app.workspace.getLeavesOfType('my-view-type')[0];
  if (!leaf) {
    leaf = this.app.workspace.getRightLeaf(false)!;
    await leaf.setViewState({ type: 'my-view-type', active: true });
  }
  this.app.workspace.revealLeaf(leaf);
}

Other UI

// Ribbon icon
this.addRibbonIcon('dice', 'Tooltip text', (evt) => {});

// Status bar
const statusEl = this.addStatusBarItem();
statusEl.setText('Status text');

// Notice (toast)
new Notice('Message to user');
new Notice('Persistent message', 0); // 0 = no auto-dismiss

// Context menu
this.registerEvent(
	this.app.workspace.on('file-menu', (menu, file) => {
		menu.addItem((item) => {
			item
				.setTitle('My action')
				.setIcon('icon')
				.onClick(() => {});
		});
	})
);

// Editor context menu
this.registerEvent(
	this.app.workspace.on('editor-menu', (menu, editor, info) => {
		menu.addItem((item) => {
			item.setTitle('Editor action').onClick(() => {});
		});
	})
);

// HTML elements (Obsidian extends HTMLElement)
const div = containerEl.createDiv({ cls: 'my-class', text: 'Hello' });
const el = containerEl.createEl('span', { cls: 'highlight', attr: { 'data-id': '1' } });
el.empty(); // remove all children
el.addClass('new-class');
el.toggleClass('active', true);

// Icons (Lucide icons built in)
import { setIcon } from 'obsidian';
setIcon(element, 'lucide-icon-name'); // e.g. 'bot', 'settings', 'file-text'

Events

Always use this.registerEvent() to ensure automatic cleanup on plugin unload:

// Vault events
this.registerEvent(this.app.vault.on('create', (file) => {}));
this.registerEvent(this.app.vault.on('modify', (file) => {}));
this.registerEvent(this.app.vault.on('delete', (file) => {}));
this.registerEvent(this.app.vault.on('rename', (file, oldPath) => {}));

// Workspace events
this.registerEvent(this.app.workspace.on('file-open', (file) => {}));
this.registerEvent(this.app.workspace.on('active-leaf-change', (leaf) => {}));
this.registerEvent(this.app.workspace.on('layout-change', () => {}));
this.registerEvent(this.app.workspace.on('editor-change', (editor, info) => {}));

// MetadataCache events
this.registerEvent(this.app.metadataCache.on('changed', (file, data, cache) => {}));
this.registerEvent(this.app.metadataCache.on('resolved', () => {}));

// Timed intervals
this.registerInterval(window.setInterval(() => {}, 60000));

// DOM events (auto-cleaned up)
this.registerDomEvent(document, 'click', (evt) => {});

Network requests

Always use requestUrl instead of fetch for cross-platform compatibility (desktop + mobile):

import { requestUrl } from 'obsidian';

const response = await requestUrl({
	url: 'https://api.example.com/data',
	method: 'POST',
	headers: { Authorization: 'Bearer TOKEN' },
	contentType: 'application/json',
	body: JSON.stringify({ key: 'value' }),
});
const data = response.json; // parsed JSON
const text = response.text; // raw text
const status = response.status;

Markdown rendering

import { MarkdownRenderer } from 'obsidian';

await MarkdownRenderer.render(
	this.app,
	'# Heading\nSome **bold** and a [[link]].',
	containerEl,
	'', // sourcePath for resolving links
	this // Component for lifecycle management
);

Key best practices

1. Always use Obsidian API over low-level alternatives: vault.getMarkdownFiles() not vault.adapter.list(), fileManager.processFrontMatter() not manual YAML parsing, app.metadataCache not re-parsing files
2. Register everything for cleanup: Use this.registerEvent(), this.registerInterval(), this.registerDomEvent(), this.addCommand(), this.addSettingTab(), this.registerView() - they all auto-clean on unload
3. Use requestUrl not fetch: Required for mobile compatibility
4. Wait for layout: Use this.app.workspace.onLayoutReady() before accessing UI
5. Check instanceof: Always verify TFile vs TFolder when using getAbstractFileByPath()
6. Use CSS variables: Use Obsidian's theme variables for styling, test in both light and dark themes
7. Use setIcon(): Use import { setIcon } from 'obsidian' with Lucide icon names
8. Debounce frequent operations: Use import { debounce } from 'obsidian' for editor changes or API calls
9. Use normalized paths: Obsidian uses forward slashes on all platforms
10. Never block the main thread: Use async/await for file operations, API calls, and heavy computations

Obsidian CLI

Obsidian 1.12+ includes a CLI for terminal-based vault interaction. See the CLI reference for complete command documentation.

Key developer commands:

• obsidian dev:eval code="expression" - Execute JavaScript in the app console
• obsidian dev:console - View captured console messages
• obsidian dev:dom query="selector" - Query DOM elements
• obsidian dev:css query="selector" - Inspect CSS with source locations
• obsidian dev:screenshot - Capture app screenshots
• obsidian dev:mobile - Toggle mobile emulation
• obsidian dev:errors - Display captured errors
• obsidian plugin:reload - Reload plugins during development

Further reading

• TypeScript API Reference - Complete class and interface definitions
• CLI Reference - Full Obsidian CLI command documentation
• Best Practices - Detailed patterns and anti-patterns

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