Agent Skills: Obsidian Hello World

Obsidian Hello World

Overview

Build a minimal working Obsidian plugin demonstrating the five core building blocks: commands (palette + editor + checkCallback), settings tab with typed config, ribbon icons, modals, and status bar. Every snippet uses real Obsidian API.

Prerequisites

• Completed obsidian-install-auth setup (symlinked dev vault, npm run dev working)
• Build pipeline producing main.js from src/main.ts

Instructions

Step 1: Define Typed Settings

// src/main.ts — top of file
import {
  App, Editor, MarkdownView, Modal, Notice,
  Plugin, PluginSettingTab, Setting, TFile
} from 'obsidian';

interface MyPluginSettings {
  greeting: string;
  showRibbon: boolean;
  dateFormat: string;
}

const DEFAULT_SETTINGS: MyPluginSettings = {
  greeting: 'Hello, Obsidian!',
  showRibbon: true,
  dateFormat: 'YYYY-MM-DD',
};

Step 2: Create the Plugin Class with Commands

export default class MyPlugin extends Plugin {
  settings: MyPluginSettings;

  async onload() {
    await this.loadSettings();

    // Ribbon icon — shows greeting as Notice
    if (this.settings.showRibbon) {
      this.addRibbonIcon('sparkles', 'My Plugin: Greet', () => {
        new Notice(this.settings.greeting);
      });
    }

    // Command: show greeting (available everywhere)
    this.addCommand({
      id: 'show-greeting',
      name: 'Show greeting',
      callback: () => new Notice(this.settings.greeting),
    });

    // Command: insert greeting at cursor (editor-only — greyed out when no editor is active)
    this.addCommand({
      id: 'insert-greeting',
      name: 'Insert greeting at cursor',
      editorCallback: (editor: Editor, view: MarkdownView) => {
        editor.replaceSelection(this.settings.greeting);
      },
    });

    // Command: word count with checkCallback (conditionally available)
    this.addCommand({
      id: 'count-words',
      name: 'Count words in current note',
      checkCallback: (checking: boolean) => {
        const view = this.app.workspace.getActiveViewOfType(MarkdownView);
        if (view) {
          if (!checking) {
            const text = view.editor.getValue();
            const count = text.split(/\s+/).filter(Boolean).length;
            new Notice(`Word count: ${count}`);
          }
          return true; // command is available
        }
        return false; // hide from palette when no editor
      },
    });

    // Command: open modal dialog
    this.addCommand({
      id: 'show-greeting-modal',
      name: 'Show greeting modal',
      callback: () => new GreetingModal(this.app, this.settings.greeting).open(),
    });

    // Command: insert today's date
    this.addCommand({
      id: 'insert-date',
      name: 'Insert today\'s date',
      editorCallback: (editor: Editor) => {
        const today = new Date().toISOString().slice(0, 10);
        editor.replaceSelection(today);
      },
    });

    // Status bar — persistent widget at bottom
    const statusEl = this.addStatusBarItem();
    statusEl.setText('Plugin loaded');

    // Update status bar when active file changes
    this.registerEvent(
      this.app.workspace.on('active-leaf-change', () => {
        const view = this.app.workspace.getActiveViewOfType(MarkdownView);
        if (view) {
          const count = view.editor.getValue().split(/\s+/).filter(Boolean).length;
          statusEl.setText(`Words: ${count}`);
        } else {
          statusEl.setText('No editor');
        }
      })
    );

    // Settings tab
    this.addSettingTab(new MySettingTab(this.app, this));
    console.log(`[${this.manifest.id}] loaded`);
  }

  onunload() {
    console.log(`[${this.manifest.id}] unloaded`);
  }

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

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

Step 3: Create Settings Tab

class MySettingTab extends PluginSettingTab {
  plugin: MyPlugin;

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

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

    new Setting(containerEl)
      .setName('Greeting message')
      .setDesc('Text shown by the greet command and ribbon icon.')
      .addText(text => text
        .setPlaceholder('Hello, Obsidian!')
        .setValue(this.plugin.settings.greeting)
        .onChange(async (value) => {
          this.plugin.settings.greeting = value;
          await this.plugin.saveSettings();
        }));

    new Setting(containerEl)
      .setName('Show ribbon icon')
      .setDesc('Toggle the sparkles icon in the left ribbon. Reload plugin to apply.')
      .addToggle(toggle => toggle
        .setValue(this.plugin.settings.showRibbon)
        .onChange(async (value) => {
          this.plugin.settings.showRibbon = value;
          await this.plugin.saveSettings();
        }));

    new Setting(containerEl)
      .setName('Date format')
      .setDesc('Format for the Insert Date command.')
      .addDropdown(dropdown => dropdown
        .addOption('YYYY-MM-DD', '2026-03-22')
        .addOption('MM/DD/YYYY', '03/22/2026')
        .addOption('DD.MM.YYYY', '22.03.2026')
        .setValue(this.plugin.settings.dateFormat)
        .onChange(async (value) => {
          this.plugin.settings.dateFormat = value;
          await this.plugin.saveSettings();
        }));
  }
}

Step 4: Create a Modal

class GreetingModal extends Modal {
  message: string;

  constructor(app: App, message: string) {
    super(app);
    this.message = message;
  }

  onOpen() {
    const { contentEl } = this;
    contentEl.createEl('h2', { text: this.message });
    contentEl.createEl('p', { text: 'This is a modal dialog from your plugin.' });

    // Add a button that does something
    const btn = contentEl.createEl('button', { text: 'Count vault files' });
    btn.addEventListener('click', () => {
      const count = this.app.vault.getMarkdownFiles().length;
      contentEl.createEl('p', { text: `Your vault has ${count} markdown files.` });
    });
  }

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

Step 5: Build and Test

set -euo pipefail
npm run build

# In Obsidian:
# 1. Settings > Community plugins > Enable your plugin
# 2. Click the sparkles icon in the ribbon
# 3. Ctrl+P > "Show greeting"
# 4. Ctrl+P > "Count words in current note" (open a .md file first)
# 5. Ctrl+P > "Show greeting modal"
# 6. Settings > My Plugin > change the greeting
# 7. Check the status bar at bottom for word count

Step 6: Listen to Vault Events

// Add to onload() — react to file changes
this.registerEvent(
  this.app.workspace.on('file-open', (file: TFile | null) => {
    if (file) {
      console.log(`[${this.manifest.id}] Opened: ${file.path}`);
    }
  })
);

// Track file modifications (debounce for production — see obsidian-rate-limits)
this.registerEvent(
  this.app.vault.on('create', (file) => {
    if (file instanceof TFile) {
      new Notice(`New file: ${file.basename}`);
    }
  })
);

Output

• Working plugin with:
  • Three command types: callback, editorCallback, checkCallback
  • Settings tab with text, toggle, and dropdown controls
  • Ribbon icon with click handler
  • Modal dialog with interactive button
  • Status bar widget with live word count
  • Event listeners for file-open and file-create

Error Handling

| Error | Cause | Solution | |-------|-------|----------| | Plugin not loading | Build errors or bad manifest | Check console (Ctrl+Shift+I) for red errors | | Settings not saving | Missing await on saveData | Always await this.saveSettings() in onChange | | Command greyed out | editorCallback needs active editor | Open a markdown note, or use callback instead | | Ribbon icon missing | Invalid icon name | Use Lucide icon names: sparkles, file-text, search | | Status bar not updating | Event not registered | Wrap in this.registerEvent() for auto-cleanup | | Settings reset on restart | Forgot saveData call | loadData returns null on first run — Object.assign handles this |

Examples

Available Lucide Icon Names

Obsidian uses Lucide icons. Common examples:

• file-text, folder, search, settings, star
• heart, bookmark, tag, link, external-link
• edit, trash-2, copy, clipboard, check
• dice, bot, sparkles, wand, calendar
• bar-chart-2, globe, download, upload

Command Types Summary

| Type | When Available | Use Case | |------|---------------|----------| | callback | Always | Non-editor commands (open modal, toggle feature) | | editorCallback | When editor is active | Insert text, transform selection | | checkCallback | Conditionally | Show/hide based on context |

Register a Hotkey-Ready Command

// Users assign hotkeys in Settings > Hotkeys
this.addCommand({
  id: 'toggle-feature',
  name: 'Toggle my feature',
  callback: () => this.toggleFeature(),
});

Resources

• Obsidian Plugin API
• Plugin Development Workflow
• Lucide Icons — icon names for addRibbonIcon
• Obsidian Hub — community knowledge base

Next Steps

• Set up hot-reload development: obsidian-local-dev-loop
• Build advanced UI (views, fuzzy search, context menus): obsidian-core-workflow-b
• Apply production patterns: obsidian-sdk-patterns