update_book_notes · Narrarium MCP: Risk & Policy

WHAT IT DOES

What update_book_notes does on Narrarium

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

WHY IT NEEDS A POLICY

Why update_book_notes needs a policy

This tool modifies data (book notes/story-design documents) in a reversible manner—updates can be undone or corrected in subsequent calls. It does not delete data (would be Destructive), execute arbitrary code (would be Execute), or handle financial transactions (would be Financial).

From the tool's definition Tool description states 'Update the global working notes or story-design document' with options to append or replace content. The verb 'Update' and the capability to modify persistent document state clearly indicate a Write operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_book_notes Rate-limited

update_book_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": {
    "update_book_notes": {
      "limits": [
        {
          "counter": "update_book_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 Narrarium, so you can run agents against it safely.

FAQ

Questions about update_book_notes

What does the update_book_notes tool do? +

Update the global working notes or story-design document. Use appendBody when the user asks you to keep a note without replacing the whole file. It is categorised as a Write tool in the Narrarium MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on update_book_notes? +

Register the Narrarium MCP server in PolicyLayer and add a rule for update_book_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 Narrarium. Nothing to install.

What risk level is update_book_notes? +

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

Can I rate-limit update_book_notes? +

Yes. Add a rate_limit block to the update_book_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 update_book_notes completely? +

Set action: deny in the PolicyLayer policy for update_book_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 update_book_notes? +

update_book_notes is provided by the Narrarium MCP server (narrarium-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.