Add physics body to an object
AI agents use make_physical to create or update resources in Threlte — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Threlte environment.
This tool modifies an existing 3D object by adding a physics body to it. This is a reversible write operation (the physics body can be removed), not destructive. The blast radius is medium since misuse could alter scene behavior unexpectedly, but it doesn't delete data or execute arbitrary code.
From the tool's definition "Add physics body to an object" — creates/attaches a new physics component to an existing scene object
Documented attack patterns abuse exactly the kind of access make_physical gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Threlte, and nothing reaches the server without passing your rules. This is the rule we recommend for make_physical:
{
"version": "1",
"default": "deny",
"tools": {
"make_physical": {
"limits": [
{
"counter": "make_physical_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}make_physical 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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Add physics body to an object. It is categorised as a Write tool in the Threlte MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Threlte MCP server in PolicyLayer and add a rule for make_physical: 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 Threlte. Nothing to install.
make_physical 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 make_physical 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 make_physical. 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.
make_physical is provided by the Threlte MCP server (serifeusstudio/threlte-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Threlte, 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.
30 Threlte tools catalogued and risk-classified — across an index of 43,000+ MCP servers.