property_set · Obsidian Local MCP: Risk & Policy

WHAT IT DOES

What property_set does on Obsidian Local

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

WHY IT NEEDS A POLICY

Why property_set needs a policy

This tool modifies frontmatter properties (metadata) within Obsidian notes. Frontmatter properties are YAML key-value pairs at the top of markdown files. Setting properties is reversible—an agent can set them to different values, delete them, or revert changes. This is a Write operation, not Destructive, since the action can be undone.

From the tool's definition Tool name 'property_set' and description 'Set a frontmatter property on a note' indicate modification of note metadata. The verb 'set' combined with 'frontmatter property' confirms this creates or modifies data reversibly.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

property_set Rate-limited

property_set 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": {
    "property_set": {
      "limits": [
        {
          "counter": "property_set_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 Obsidian Local, so you can run agents against it safely.

FAQ

Questions about property_set

What does the property_set tool do? +

Set a frontmatter property on a note. It is categorised as a Write tool in the Obsidian Local MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on property_set? +

Register the Obsidian Local MCP server in PolicyLayer and add a rule for property_set: 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 property_set? +

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

Can I rate-limit property_set? +

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

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

property_set 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.