notebook_create · Jupyter MCP: Risk & Policy

WHAT IT DOES

What notebook_create does on JupyterMCP

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

WHY IT NEEDS A POLICY

Why notebook_create needs a policy

This tool creates a new file (reversible write operation). While file creation is not destructive and has limited blast radius compared to Execute or Destructive actions, it modifies the file system state. Severity is medium because an agent could create many notebooks or occupy disk space, but the action is reversible via deletion.

From the tool's definition Tool name 'notebook_create' and description 'Create a new Jupyter notebook (.ipynb) in the working directory' clearly indicate file creation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

notebook_create Rate-limited

notebook_create 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": {
    "notebook_create": {
      "limits": [
        {
          "counter": "notebook_create_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 JupyterMCP, so you can run agents against it safely.

FAQ

Questions about notebook_create

What does the notebook_create tool do? +

Create a new Jupyter notebook (.ipynb) in the working directory. It is categorised as a Write tool in the JupyterMCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on notebook_create? +

Register the Jupyter MCP server in PolicyLayer and add a rule for notebook_create: 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 JupyterMCP. Nothing to install.

What risk level is notebook_create? +

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

Can I rate-limit notebook_create? +

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

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

notebook_create is provided by the Jupyter MCP server (try3d/jupytermcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.