modify_object · Blender MCP: Risk & Policy

WHAT IT DOES

What modify_object does on Blender MCP

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

WHY IT NEEDS A POLICY

Why modify_object needs a policy

The name 'modify_object' strongly implies modifying an existing 3D object in Blender (e.g., changing position, scale, material, etc.), which is a reversible Write operation. However, the description is empty, lowering confidence. It sits alongside 'delete_object' and 'execute_python' which are more severe, and 'create_object' which is Write — 'modify_object' most plausibly fits Write.

From the tool's definition Tool name 'modify_object' on a server that enables control of Blender 3D for 'object creation, modification, deletion, and Python script execution'

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

modify_object Rate-limited

modify_object 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": {
    "modify_object": {
      "limits": [
        {
          "counter": "modify_object_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 Blender MCP, so you can run agents against it safely.

FAQ

Questions about modify_object

What does the modify_object tool do? +

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

How do I enforce a policy on modify_object? +

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

What risk level is modify_object? +

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

Can I rate-limit modify_object? +

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

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

modify_object is provided by the Blender MCP server (nowcika/blender_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.