open · Obsidian Local MCP: Risk & Policy

WHAT IT DOES

What open does on Obsidian Local

AI agents invoke open to trigger actions in Obsidian Local. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why open needs a policy

This tool triggers an external UI operation in Obsidian (opening a file in the application interface), which constitutes an action that affects the running application's state. It's not a pure read (it changes the UI state/focus), and it executes an Obsidian internal command. Given the server description mentions 'execution of internal Obsidian commands', this fits Execute.

From the tool's definition Open a file in the Obsidian UI

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

open Rate-limited

open stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "open": {
      "limits": [
        {
          "counter": "open_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about open

What does the open tool do? +

Open a file in the Obsidian UI. It is categorised as a Execute tool in the Obsidian Local MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on open? +

Register the Obsidian Local MCP server in PolicyLayer and add a rule for open: 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 Obsidian Local. Nothing to install.

What risk level is open? +

open is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit open? +

Yes. Add a rate_limit block to the open 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 open completely? +

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

open is provided by the Obsidian Local MCP server (matthewsuazo/obsidian-local-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.