entity_create_spline

THE RISK

Medium Risk

Why entity_create_spline needs a policy

This tool creates new drawing objects (spline entities), modifying the CAD document state. It is Write rather than Execute because it performs a specific, bounded geometric operation (spline creation) rather than executing arbitrary code. It is not Destructive because spline creation is reversible (can be undone/deleted).

From the tool's definition Tool name 'entity_create_spline' and description 'Create a NURBS spline curve passing through the specified fit points' indicate irreversible creation of new geometric entities in a CAD drawing.

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

POLICY

How to control entity_create_spline

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

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "entity_create_spline": {
      "limits": [
        {
          "counter": "entity_create_spline_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

entity_create_spline 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.

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

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More AutoCAD MCP Pro tools

Destructive construction_clear Delete every entity on the CONSTRUCTION layer. Idempotent. Destructive drawing_purge Purge all unused objects (layers, blocks, linetypes, styles) from the drawing. Destructive entity_delete Permanently delete an entity by its handle. Destructive entity_delete_many Delete multiple entities in one call. Returns count of deleted entities. Destructive layer_delete layer_delete Destructive block_explode block_explode Execute drawing_audit Run an integrity audit on the drawing to detect and fix errors. Execute system_run_command system_run_command

All 108 AutoCAD MCP Pro tools →

Write tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about entity_create_spline

What does the entity_create_spline tool do? +

Create a NURBS spline curve passing through the specified fit points. It is categorised as a Write tool in the AutoCAD MCP Pro MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on entity_create_spline? +

Register the AutoCAD MCP Pro MCP server in PolicyLayer and add a rule for entity_create_spline: 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 AutoCAD MCP Pro. Nothing to install.

What risk level is entity_create_spline? +

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

Can I rate-limit entity_create_spline? +

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

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

entity_create_spline is provided by the AutoCAD MCP Pro MCP server (u-c4n/autocad-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every AutoCAD MCP Pro tool call.

Start from AutoCAD MCP Pro, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →