AI agents use entity_create_block_ref to create or update resources in AutoCAD MCP Pro — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your AutoCAD MCP Pro environment.
Creating a block reference in AutoCAD adds a new drawable entity to the document, which modifies the design reversibly. This is a Write operation—the change can be undone (undo/delete the reference) and does not destroy existing data. Severity is medium because misuse could pollute a critical design file with unwanted references, but the effect is reversible and localized to the current session unless saved.
From the tool's definition Tool name 'entity_create_block_ref' indicates creation of a block reference entity in AutoCAD. The 'create' verb and context of sibling tools like 'block_create_from_entities' and 'block_explode' confirm it modifies the CAD drawing by adding/inserting a new…
Documented attack patterns abuse exactly the kind of access entity_create_block_ref gives an agent:
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_block_ref:
{
"version": "1",
"default": "deny",
"tools": {
"entity_create_block_ref": {
"limits": [
{
"counter": "entity_create_block_ref_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
} entity_create_block_ref 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.
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entity_create_block_ref. 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.
Register the AutoCAD MCP Pro MCP server in PolicyLayer and add a rule for entity_create_block_ref: 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.
entity_create_block_ref is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the entity_create_block_ref 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.
Set action: deny in the PolicyLayer policy for entity_create_block_ref. 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.
entity_create_block_ref 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.
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.
Free to start. No card required.
108 AutoCAD MCP Pro tools catalogued and risk-classified — across an index of 43,000+ MCP servers.