update_chapter_notes · Narrarium MCP: Risk & Policy

WHAT IT DOES

What update_chapter_notes does on Narrarium

AI agents use update_chapter_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_chapter_notes needs a policy

This tool performs write operations on chapter notes files—it creates new notes or modifies existing ones, but these changes are reversible and do not destructively overwrite data or have system-wide side effects. The blast radius is limited to a specific chapter's notes file, making it a straightforward Write-category operation with low severity. No financial, destructive, or execution risk is present.

From the tool's definition Tool description states 'Update or append chapter-specific working notes stored in drafts/<chapter>/notes.md', which creates or modifies data (notes) in a reversible manner.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_chapter_notes Rate-limited

update_chapter_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_chapter_notes": {
      "limits": [
        {
          "counter": "update_chapter_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_chapter_notes

What does the update_chapter_notes tool do? +

Update or append chapter-specific working notes stored in drafts/<chapter>/notes.md. Use this when the user wants to keep or refine notes tied to a chapter draft. 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_chapter_notes? +

Register the Narrarium MCP server in PolicyLayer and add a rule for update_chapter_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_chapter_notes? +

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

Can I rate-limit update_chapter_notes? +

Yes. Add a rate_limit block to the update_chapter_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_chapter_notes completely? +

Set action: deny in the PolicyLayer policy for update_chapter_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_chapter_notes? +

update_chapter_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.