note_write · Knowledge Wiki MCP: Risk & Policy

WHAT IT DOES

What note_write does on Knowledge Wiki

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

WHY IT NEEDS A POLICY

Why note_write needs a policy

This tool creates or modifies notes in the Obsidian vault (vault/01_Notes), which is a reversible action. It does not delete data (thus not Destructive), does not execute arbitrary code (thus not Execute), and does not involve financial transactions (thus not Financial).

From the tool's definition Tool description explicitly states 'Write a note' and 'note_write' as the function name, indicating creation or modification of note content in the vault.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

note_write Rate-limited

note_write 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": {
    "note_write": {
      "limits": [
        {
          "counter": "note_write_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 Knowledge Wiki, so you can run agents against it safely.

FAQ

Questions about note_write

What does the note_write tool do? +

Write a note under vault/01_Notes by type. Does not write vault/04_Knowledge. It is categorised as a Write tool in the Knowledge Wiki MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on note_write? +

Register the Knowledge Wiki MCP server in PolicyLayer and add a rule for note_write: 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 Knowledge Wiki. Nothing to install.

What risk level is note_write? +

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

Can I rate-limit note_write? +

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

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

note_write is provided by the Knowledge Wiki MCP server (pongs1/knowledge-wiki-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.