AI agents use scene_add_primitive to create or update resources in 8th Wall MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your 8th Wall MCP Server environment.
This tool creates new 3D primitive shapes within an AR scene, which is a reversible write operation. It adds data structures to the scene graph without deleting or executing external code. While it could theoretically be misused to clutter or degrade performance, the blast radius is limited to the current AR scene composition and can be undone by removing the primitives.
From the tool's definition Tool name 'scene_add_primitive' and description 'Add a primitive shape to the scene' indicate creation of new scene elements. The verb 'add' and context of building WebAR experiences confirm this modifies scene state by creating new 3D objects.
Documented attack patterns abuse exactly the kind of access scene_add_primitive gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and 8th Wall MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for scene_add_primitive:
{
"version": "1",
"default": "deny",
"tools": {
"scene_add_primitive": {
"limits": [
{
"counter": "scene_add_primitive_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}scene_add_primitive 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 a primitive shape to the scene. It is categorised as a Write tool in the 8th Wall MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the 8th Wall MCP Server MCP server in PolicyLayer and add a rule for scene_add_primitive: 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 8th Wall MCP Server. Nothing to install.
scene_add_primitive 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 scene_add_primitive 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 scene_add_primitive. 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.
scene_add_primitive is provided by the 8th Wall MCP Server MCP server (superdwayne/8thwallmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from 8th Wall MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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64 8th Wall MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.