edit_and_run_cell · Marimo MCP: Risk & Policy

WHAT IT DOES

What edit_and_run_cell does on Marimo

AI agents invoke edit_and_run_cell to trigger actions in Marimo. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why edit_and_run_cell needs a policy

The tool name 'edit_and_run_cell' strongly implies it both edits (modifies) and runs (executes) a notebook cell. Since execution is involved — running arbitrary code in a notebook context — this falls under Execute, which is more severe than Write. The server description confirms the server supports 'editing, and running cells'. Misuse could execute arbitrary code with high blast radius.

From the tool's definition Tool name: 'edit_and_run_cell' — implies both modifying a cell's content (Write) and executing it (Execute). Server description mentions 'editing, and running cells via MCP'.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

edit_and_run_cell Rate-limited

edit_and_run_cell stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "edit_and_run_cell": {
      "limits": [
        {
          "counter": "edit_and_run_cell_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Marimo, so you can run agents against it safely.

FAQ

Questions about edit_and_run_cell

What does the edit_and_run_cell tool do? +

edit_and_run_cell. It is categorised as a Execute tool in the Marimo MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on edit_and_run_cell? +

Register the Marimo MCP server in PolicyLayer and add a rule for edit_and_run_cell: 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 Marimo. Nothing to install.

What risk level is edit_and_run_cell? +

edit_and_run_cell is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit edit_and_run_cell? +

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

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

edit_and_run_cell is provided by the Marimo MCP server (vladisluv12/marimo-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.