ipynb_set_kernel · Jupyter Editor MCP: Risk & Policy

WHAT IT DOES

What ipynb_set_kernel does on Jupyter Editor

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

WHY IT NEEDS A POLICY

Why ipynb_set_kernel needs a policy

Setting a kernel is a reversible write operation that modifies notebook metadata but does not delete data or execute arbitrary code directly. However, it could indirectly alter execution behavior if misapplied. Confidence is moderate because the description is empty, limiting certainty about exact behavior.

From the tool's definition Tool name 'ipynb_set_kernel' indicates modification of notebook kernel metadata. Sibling tools like 'ipynb_append_cell', 'ipynb_clear_outputs', and 'ipynb_delete_cell' are explicitly Write/Destructive operations, placing this in a modifying context.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

ipynb_set_kernel Rate-limited

ipynb_set_kernel 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": {
    "ipynb_set_kernel": {
      "limits": [
        {
          "counter": "ipynb_set_kernel_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 Jupyter Editor, so you can run agents against it safely.

FAQ

Questions about ipynb_set_kernel

What does the ipynb_set_kernel tool do? +

ipynb_set_kernel. It is categorised as a Write tool in the Jupyter Editor MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on ipynb_set_kernel? +

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

What risk level is ipynb_set_kernel? +

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

Can I rate-limit ipynb_set_kernel? +

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

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

ipynb_set_kernel is provided by the Jupyter Editor MCP server (jsamuel1/jupyter-editor-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.