obsidian_write_note · Mcp Apple Obsidian MCP: Risk & Policy

WHAT IT DOES

What obsidian_write_note does on Mcp Apple Obsidian

AI agents use obsidian_write_note to create or update resources in Mcp Apple Obsidian — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Mcp Apple Obsidian environment.

WHY IT NEEDS A POLICY

Why obsidian_write_note needs a policy

The tool creates or modifies note data in Obsidian vaults reversibly. This is a Write operation rather than Read (retrieves data), Execute (runs code), Destructive (irreversible deletion), or Financial. Severity is medium because unintended modifications to notes could cause data loss or confusion, though it's reversible unlike Destructive operations.

From the tool's definition Tool name 'obsidian_write_note' indicates modification of note content. Context from sibling tools (obsidian_create_note, obsidian_append_note) and server description stating 'tools for interacting with Obsidian vaults, notes' confirms write capability.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

obsidian_write_note Rate-limited

obsidian_write_note stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "obsidian_write_note": {
      "limits": [
        {
          "counter": "obsidian_write_note_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Mcp Apple Obsidian, so you can run agents against it safely.

FAQ

Questions about obsidian_write_note

What does the obsidian_write_note tool do? +

obsidian_write_note. It is categorised as a Write tool in the Mcp Apple Obsidian MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on obsidian_write_note? +

Register the Mcp Apple Obsidian MCP server in PolicyLayer and add a rule for obsidian_write_note: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Mcp Apple Obsidian. Nothing to install.

What risk level is obsidian_write_note? +

obsidian_write_note is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit obsidian_write_note? +

Yes. Add a rate_limit block to the obsidian_write_note rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block obsidian_write_note completely? +

Set action: deny in the PolicyLayer policy for obsidian_write_note. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides obsidian_write_note? +

obsidian_write_note is provided by the Mcp Apple Obsidian MCP server (rex/mcp-apple-obsidian). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.