patch_note · Obsidian MCP: Risk & Policy

WHAT IT DOES

What patch_note does on Obsidian

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

WHY IT NEEDS A POLICY

Why patch_note needs a policy

This tool modifies existing notes by inserting or appending content at specific locations (under headings, block references, or frontmatter fields), making it a Write operation. The change is reversible (inserted content can be deleted).

From the tool's definition Tool description states it can "Insert content relative to a heading, block reference, or frontmatter field" and provides an example of appending a bullet.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

patch_note Rate-limited

patch_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": {
    "patch_note": {
      "limits": [
        {
          "counter": "patch_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 Obsidian, so you can run agents against it safely.

FAQ

Questions about patch_note

What does the patch_note tool do? +

Insert content relative to a heading, block reference, or frontmatter field — without rewriting the whole note. Example: append a bullet under. It is categorised as a Write tool in the 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 patch_note? +

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

What risk level is patch_note? +

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

Can I rate-limit patch_note? +

Yes. Add a rate_limit block to the patch_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 patch_note completely? +

Set action: deny in the PolicyLayer policy for patch_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 patch_note? +

patch_note is provided by the Obsidian MCP server (yanxue06/obsidian-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.