AI agents use create_arc to create or update resources in GOLEM-3DMCP-Rhino- — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your GOLEM-3DMCP-Rhino- environment.
This tool creates a new arc geometry object in Rhino, which is a reversible Write operation. It adds new data to the model but does not execute arbitrary code, delete irreversibly, or move money. The severity is medium because misuse could add unwanted geometry to a model, but the effect is recoverable through undo/deletion.
From the tool's definition Tool is part of GOLEM-3DMCP server which provides 'direct, programmatic control of Rhino 8' to 'create geometry.' The tool name 'create_arc' and its presence among sibling tools like 'align_objects', 'apply_transform', 'array_objects_linear' indicates it…
Documented attack patterns abuse exactly the kind of access create_arc gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and GOLEM-3DMCP-Rhino-, and nothing reaches the server without passing your rules. This is the rule we recommend for create_arc:
{
"version": "1",
"default": "deny",
"tools": {
"create_arc": {
"limits": [
{
"counter": "create_arc_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_arc 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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create_arc. It is categorised as a Write tool in the GOLEM-3DMCP-Rhino- MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the GOLEM-3DMCP-Rhino- MCP server in PolicyLayer and add a rule for create_arc: 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 GOLEM-3DMCP-Rhino-. Nothing to install.
create_arc 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 create_arc 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 create_arc. 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.
create_arc is provided by the GOLEM-3DMCP-Rhino- MCP server (thekinghippopotamus/golem-3dmcp-rhino-). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from GOLEM-3DMCP-Rhino-, 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.
89 GOLEM-3DMCP-Rhino- tools catalogued and risk-classified — across an index of 43,000+ MCP servers.