execute_blender_code · Blender MCP: Risk & Policy

WHAT IT DOES

What execute_blender_code does on BlenderMCP

AI agents invoke execute_blender_code to trigger actions in BlenderMCP. 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 execute_blender_code needs a policy

This tool allows execution of arbitrary code within Blender's Python environment. Arbitrary code execution is the definition of the Execute category. The severity is critical because: (1) Python code in Blender has access to the full Blender API and can modify scenes, models, and files; (2) it could import arbitrary libraries and perform network operations, file I/O, or system calls; (3) a misconfigured or…

From the tool's definition "Execute arbitrary Python code in Blender" — the tool explicitly permits execution of arbitrary Python code in a running Blender instance, with no apparent restrictions or sandboxing.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

execute_blender_code Rate-limited

execute_blender_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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "execute_blender_code": {
      "limits": [
        {
          "counter": "execute_blender_code_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 BlenderMCP, so you can run agents against it safely.

FAQ

Questions about execute_blender_code

What does the execute_blender_code tool do? +

Execute arbitrary Python code in Blender. Make sure to do it step-by-step by breaking it into smaller chunks. It is categorised as a Execute tool in the BlenderMCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on execute_blender_code? +

Register the Blender MCP server in PolicyLayer and add a rule for execute_blender_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 BlenderMCP. Nothing to install.

What risk level is execute_blender_code? +

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

Can I rate-limit execute_blender_code? +

Yes. Add a rate_limit block to the execute_blender_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 execute_blender_code completely? +

Set action: deny in the PolicyLayer policy for execute_blender_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 execute_blender_code? +

execute_blender_code is provided by the Blender MCP server (spranjal3301/final-year-project). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.