create_item · Narrarium MCP: Risk & Policy

WHAT IT DOES

What create_item does on Narrarium

AI agents use create_item 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 create_item needs a policy

This tool creates new data structures (item files) in a reversible manner typical of Write operations. While it adds content to the Narrarium repository, it does not execute arbitrary code, delete data, or cause financial impact. The reversibility of creation (items can be edited or removed) and the write-focused nature place this in the Write category.

From the tool's definition Tool description states it will 'Create a rich item file' with various attributes. The verb 'Create' and the action of generating a new file with structured data (appearance, purpose, significance, ownership) clearly indicates data creation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_item Rate-limited

create_item 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": {
    "create_item": {
      "limits": [
        {
          "counter": "create_item_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 create_item

What does the create_item tool do? +

Create a rich item file with appearance, purpose, significance, ownership, and optional historical research support. 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 create_item? +

Register the Narrarium MCP server in PolicyLayer and add a rule for create_item: 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 create_item? +

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

Can I rate-limit create_item? +

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

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

create_item 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.