Roll dice using standard RPG notation (e.g., 1d20, 3d6+4)
AI agents invoke roll_dice to trigger actions in FoundryVTT MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
This tool executes a dice-rolling operation in FoundryVTT, triggering an external operation in the game system. It doesn't read existing data, write persistent data, or delete anything — it performs a computation/action with side effects (posting roll results to the chat/game state). Severity is low as the blast radius of misuse is minimal in a tabletop gaming context.
From the tool's definition Roll dice using standard RPG notation (e.g., 1d20, 3d6+4)
Documented attack patterns abuse exactly the kind of access roll_dice 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 roll_dice:
{
"version": "1",
"default": "deny",
"tools": {
"roll_dice": {
"limits": [
{
"counter": "roll_dice_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}roll_dice stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Roll dice using standard RPG notation (e.g., 1d20, 3d6+4). It is categorised as a Execute tool in the FoundryVTT MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the FoundryVTT MCP Server MCP server in PolicyLayer and add a rule for roll_dice: 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.
roll_dice is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the roll_dice 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 roll_dice. 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.
roll_dice 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.