Create an Assembly Definition Reference (.asmref) file. This lets you include scripts from a different folder into an existing assembly, useful for extending packages or splitting code across directories while keeping them in the same compilation unit.
AI agents use unity_asmdef_create_ref to create or update resources in Unity MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Unity MCP Server environment.
This tool creates a new file (.asmref) that modifies the project's assembly configuration. It is reversible (the file can be deleted or modified), so it falls under Write rather than Destructive.
From the tool's definition Tool name contains 'create' and description states 'Create an Assembly Definition Reference (.asmref) file', which involves creating a new file in the project structure.
Documented attack patterns abuse exactly the kind of access unity_asmdef_create_ref gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Unity MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for unity_asmdef_create_ref:
{
"version": "1",
"default": "deny",
"tools": {
"unity_asmdef_create_ref": {
"limits": [
{
"counter": "unity_asmdef_create_ref_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}unity_asmdef_create_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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Create an Assembly Definition Reference (.asmref) file. This lets you include scripts from a different folder into an existing assembly, useful for extending packages or splitting code across directories while keeping them in the same compilation unit. It is categorised as a Write tool in the Unity MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Unity MCP Server MCP server in PolicyLayer and add a rule for unity_asmdef_create_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 Unity MCP Server. Nothing to install.
unity_asmdef_create_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 unity_asmdef_create_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 unity_asmdef_create_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.
unity_asmdef_create_ref is provided by the Unity MCP Server MCP server (anklebreaker-studio/unity-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 324 Unity MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
324 Unity MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.