Obs186｜Local REST API & MCP Server 4.0 Major Overhaul! Search Notes, Write Files, and Manage Tags Using Natural Language

In Obs105 – The Local REST API Plugin for External Integration, I introduced the Local REST API plugin. Through the browser extension Obsidian Web, you could add URLs or selected text to a designated note. However, after upgrading the Local REST API plugin to version 4.0, the browser operations stopped working.

Upon investigation, the cause was clear: Local REST API underwent a major overhaul starting with version 4.0. It now provides not only an HTTP Server (for browser use) but also an MCP Server (for AI Agent use). The browser extension settings have also changed accordingly.

1. AI Agent Feature Demo

Notes containing "MCP server", write the results to 030-Inbox/list.md

• Because AGENTS.md contains the rule: "For simple tasks, just do them directly — no need to 'ask for directions' first.", it prioritizes using OpenCode native tools, i.e., MCP tools.

Write the results of the following query to 030-Inbox/mcp.md:
What is MCP?

1.1. Differences from Obsidian CLI

2. MCP Server Features and Configuration

2.1. MCP Available Tools

2.2. AI Agent Configuration

• For Claude and Cursor, refer to GitHub.

• OpenCode configuration is as follows:

  "mcp": {
    "obsidian": {
      "type": "remote",
      "url": "http://127.0.0.1:27123/mcp/",
      "enabled": true,
      "headers": {
        "Authorization": "Bearer YOUR_API_KEY",
      }
    }
  }

• Because Local REST API uses a self-signed certificate, using http:// directly is simpler.
• If you run the following commands before launching OpenCode, you can use "https://127.0.0.1:27124/mcp/" for the "url":

set NODE_TLS_REJECT_UNAUTHORIZED=0

rem Permanently set the environment variable
setx NODE_TLS_REJECT_UNAUTHORIZED 0

3. Installing and Enabling in Obsidian

• Search for "Local REST API" in Community Plugins, then install and enable it.
• Go to Settings → search for "Local REST API" → copy the API Key: Bearer YOUR_API_KEY
• Check "Enable non-encrypted (HTTP) server"

4. Obsidian Web Browser Extension Settings

• Right-click the Obsidian Web icon → Extension Options → modify existing Templates.

4.1. Local REST API 3.x Original Settings

• Append content: PATCH /vault/folder/note.md
  • Find the heading "2026" in the note and prepend new content at the beginning of that section.
  • The HTTP Headers format has changed in 4.0.

4.2. Local REST API 4.x New Settings

• Append content: PATCH /vault/folder/note.md
  • Find the heading "2026" in the note and prepend new content at the beginning of that section.

• Operation: append (add at the end of the section), prepend (add at the first line of the section), replace
• Target-Type: heading, block, frontmatter
  • For heading, you must use the format heading1::heading2, specifying headings from top to bottom.
• Content-Type: cannot use text/plain → use text/markdown or application/json instead.

5. 💡 Related Links

✅ Explanation article (Traditional Chinese): https://jdev.tw/blog/9217/
✅ Explanation article (English)
✅ Explanation article (Japanese)

✅ Obsidian Web browser extension: Obsidian Web - Chrome Web Store
✅ GitHub local-rest-api with MCP: https://github.com/coddingtonbear/obsidian-local-rest-api

6. Tutorial Video