obsidian_add_tag · Mcp Apple Obsidian MCP: Risk & Policy

WHAT IT DOES

What obsidian_add_tag does on Mcp Apple Obsidian

AI agents use obsidian_add_tag 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_add_tag needs a policy

This tool creates or modifies note metadata by appending a tag, which is a reversible write operation. It does not execute code, delete data, or move money. While tags affect note organization and searchability, they can be removed without permanent data loss, making this a Write rather than Destructive operation.

From the tool's definition The tool description states 'Add a tag to a note,' which modifies note metadata. The server description confirms it provides tools for 'interacting with Obsidian vaults, notes, and application state' with 'direct file system access.' Adding a tag is a…

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

obsidian_add_tag Rate-limited

obsidian_add_tag 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_add_tag": {
      "limits": [
        {
          "counter": "obsidian_add_tag_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_add_tag

What does the obsidian_add_tag tool do? +

Add a tag to a 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_add_tag? +

Register the Mcp Apple Obsidian MCP server in PolicyLayer and add a rule for obsidian_add_tag: 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_add_tag? +

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

Can I rate-limit obsidian_add_tag? +

Yes. Add a rate_limit block to the obsidian_add_tag 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_add_tag completely? +

Set action: deny in the PolicyLayer policy for obsidian_add_tag. 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_add_tag? +

obsidian_add_tag 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.