add_notes · Claude File Management Server MCP: Risk & Policy

WHAT IT DOES

What add_notes does on Claude File Management Server

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

WHY IT NEEDS A POLICY

Why add_notes needs a policy

This tool creates or modifies data (appends notes) in a reversible manner. It does not delete, execute code, move money, or trigger external operations—it simply adds text to a notes file. The operation is completely reversible by editing or deleting the appended content. Blast radius is minimal as notes are typically low-sensitivity data and appending causes no destructive side effects.

From the tool's definition Tool appends content to Notes.txt file with optional timestamp; description explicitly states 'append' which is a reversible write operation that modifies but does not irreversibly delete data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_notes Rate-limited

add_notes 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": {
    "add_notes": {
      "limits": [
        {
          "counter": "add_notes_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 Claude File Management Server, so you can run agents against it safely.

FAQ

Questions about add_notes

What does the add_notes tool do? +

Append a note to Notes.txt with optional timestamp. It is categorised as a Write tool in the Claude File Management Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on add_notes? +

Register the Claude File Management Server MCP server in PolicyLayer and add a rule for add_notes: 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 Claude File Management Server. Nothing to install.

What risk level is add_notes? +

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

Can I rate-limit add_notes? +

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

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

add_notes is provided by the Claude File Management Server MCP server (vipin1000/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.