AI agents call lookup_rule to retrieve information from FoundryVTT MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a read-only lookup of game rules and mechanics. It retrieves data from the game system's rule database without side effects, making it a Read category tool. The severity is low because misuse would only result in retrieving incorrect or irrelevant rule information, posing no risk to game state, financial data, or system integrity.
From the tool's definition Tool name 'lookup_rule' and description 'Look up game rules and mechanics' indicate a retrieval operation that queries existing rule information without modifying, executing, or deleting anything.
Documented attack patterns abuse exactly the kind of access lookup_rule gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and FoundryVTT MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for lookup_rule:
{
"version": "1",
"default": "deny",
"tools": {
"lookup_rule": {}
}
}lookup_rule is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Look up game rules and mechanics. It is categorised as a Read tool in the FoundryVTT MCP Server MCP Server, which means it retrieves data without modifying state.
Register the FoundryVTT MCP Server MCP server in PolicyLayer and add a rule for lookup_rule: 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 FoundryVTT MCP Server. Nothing to install.
lookup_rule is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the lookup_rule 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 lookup_rule. 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.
lookup_rule is provided by the FoundryVTT MCP Server MCP server (laurigates/foundryvtt-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from FoundryVTT MCP Server, 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.
25 FoundryVTT MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.