instantiate_prefab
Instantiate a prefab in the scene
This record as markdown: /tools/caravanglory-cocos-mcp-server/instantiate-prefab.md
What instantiate_prefab does on Cocos
AI agents use instantiate_prefab to create or update resources in Cocos, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Cocos environment.
Why instantiate_prefab is rated Medium
Instantiating a prefab creates a new node instance in the scene, which is a reversible write operation. It does not delete data or execute arbitrary code, but it does modify the scene by adding new content. This can be undone via the editor's undo system.
From the tool's definition Instantiate a prefab in the scene
Attacks that exploit this kind of access
The rule that runs instantiate_prefab safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Cocos, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For instantiate_prefab, this is the rule to start with:
instantiate_prefab 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.
The button opens the PolicyLayer dashboard: create your workspace, connect Cocos, apply this rule, and every instantiate_prefab call is checked against it from then on.
Questions about instantiate_prefab
Instantiate a prefab in the scene. It is categorised as a Write tool in the Cocos MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Cocos MCP server in PolicyLayer and add a rule for instantiate_prefab: 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 Cocos. Nothing to install.
instantiate_prefab 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 instantiate_prefab 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 instantiate_prefab. 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.
instantiate_prefab is provided by the Cocos MCP server (caravanglory/cocos-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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