zk_update_note · Zettelkasten MCP: Risk & Policy

WHAT IT DOES

What zk_update_note does on Zettelkasten

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

WHY IT NEEDS A POLICY

Why zk_update_note needs a policy

The tool updates existing notes within the knowledge management system, which is a reversible Write operation. The severity is medium because an adversarial AI agent could maliciously modify notes, corrupting the knowledge base or injecting false information, but updates are generally reversible (notes can be edited again or restored from version history if available).

From the tool's definition Tool name 'zk_update_note' indicates modification of existing data. The Zettelkasten server description confirms it 'allow[s] you to create, link, explore and synthesize atomic notes', and this tool performs the update operation on notes.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

zk_update_note Rate-limited

zk_update_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": {
    "zk_update_note": {
      "limits": [
        {
          "counter": "zk_update_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 Zettelkasten, so you can run agents against it safely.

FAQ

Questions about zk_update_note

What does the zk_update_note tool do? +

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

How do I enforce a policy on zk_update_note? +

Register the Zettelkasten MCP server in PolicyLayer and add a rule for zk_update_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 Zettelkasten. Nothing to install.

What risk level is zk_update_note? +

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

Can I rate-limit zk_update_note? +

Yes. Add a rate_limit block to the zk_update_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 zk_update_note completely? +

Set action: deny in the PolicyLayer policy for zk_update_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 zk_update_note? +

zk_update_note is provided by the Zettelkasten MCP server (entanglr/zettelkasten-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.