run_python_code

THE RISK

High Risk

This tool executes arbitrary Python code in the interpreter. Code execution is inherently high-risk: it can read/write files, make network calls, spawn processes, access environment variables, and trigger side effects unpredictably. The 'critical' severity reflects the maximum blast radius—an LLM misuse could compromise the entire system running the interpreter.

From the tool's definition Tool name 'run_python_code' combined with server description stating it 'allows LLMs to interact with Python environments, execute code'.

Documented attack patterns abuse exactly the kind of access run_python_code gives an agent:

HOW TO CONTROL RUN_PYTHON_CODE

PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Python Interpreter, and nothing reaches the server without passing your rules. This is the rule we recommend for run_python_code:

policy.json

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

run_python_code 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.

Create a free account and register MCP Python Interpreter — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

More MCP Python Interpreter tools

Destructive clear_session Clear a REPL session's state and history. Args: session_id: Session ID to Execute run_python_file Execute a Python file (always uses subprocess for file execution). Args: Execute install_package Install a Python package in the specified environment. Args: package_name Write write_file Write content to a file. Args: file_path: Path to the file to write Read list_directory List all Python files in a directory. Args: directory_path: Path to direc Read list_installed_packages List installed packages for a specific Python environment. Args: environm Read list_python_environments List all available Python environments (system Python and conda environments). Read list_sessions List all active REPL sessions.

All 10 MCP Python Interpreter tools →

Execute tools on other servers

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Go deeper

High-risk tools in MCP Python Interpreter → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

What does the run_python_code tool do? +

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

How do I enforce a policy on run_python_code? +

Register the MCP Python Interpreter MCP server in PolicyLayer and add a rule for run_python_code: 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 MCP Python Interpreter. Nothing to install.

What risk level is run_python_code? +

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

Can I rate-limit run_python_code? +

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

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

run_python_code is provided by the MCP Python Interpreter MCP server (yzfly/mcp-python-interpreter). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every MCP Python Interpreter tool call.

Deterministic rules across all 10 MCP Python Interpreter tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

GOVERN MCP PYTHON INTERPRETER →

Free to start. No card required.

10 MCP Python Interpreter tools catalogued and risk-classified — across an index of 42,500+ MCP servers.

// WHAT RUN_PYTHON_CODE ON MCP PYTHON INTERPRETER DOES

// THE RISK

// HOW TO CONTROL RUN_PYTHON_CODE

// EXPLORE