create_script · Narrarium MCP: Risk & Policy

WHAT IT DOES

What create_script does on Narrarium

AI agents use create_script 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_script needs a policy

This tool creates new data artifacts (scene scripts) in a persistent storage location (the scripts directory). It is reversible (scripts can be deleted or modified later) and does not execute arbitrary code or delete data. The 'Create' verb and file creation behavior classify it as Write.

From the tool's definition Tool description states 'Create a new scene script in scripts/<chapter>/<paragraph>.md', which explicitly creates a new file in a structured directory hierarchy.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_script Rate-limited

create_script 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_script": {
      "limits": [
        {
          "counter": "create_script_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_script

What does the create_script tool do? +

Create a new scene script in scripts/<chapter>/<paragraph>.md using the Narrarium script meta-language. ${SCRIPT_LEGEND} When to use - Before writing a paragraph from scratch: write the script first, then call \. 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_script? +

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

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

Can I rate-limit create_script? +

Yes. Add a rate_limit block to the create_script 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_script completely? +

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

create_script 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.