update_actor_attributes

THE RISK

Medium Risk

Why update_actor_attributes needs a policy

This tool creates or modifies actor data reversibly, fitting the Write category. Severity is high because modifying character attributes can significantly disrupt game sessions—altering abilities, health thresholds, or skill values could break campaign balance or player progression. However, it is not Destructive (changes are reversible via re-update) or Financial.

From the tool's definition Tool name 'update_actor_attributes' explicitly indicates modification of actor data. Description states 'Update attributes on an actor', confirming reversible data modification capability.

Documented attack patterns abuse exactly the kind of access update_actor_attributes gives an agent:

POLICY

How to control update_actor_attributes

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 update_actor_attributes:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "update_actor_attributes": {
      "limits": [
        {
          "counter": "update_actor_attributes_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

update_actor_attributes 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.

Create a free account and register FoundryVTT MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More FoundryVTT MCP Server tools

Destructive delete_actor_item Delete an item owned by an actor (requires FOUNDRY_WRITE_ENABLED + active Socket.IO connec Execute roll_dice Roll dice using standard RPG notation (e.g., 1d20, 3d6+4) Write create_actor_item Create an item on an actor from an inline item document (requires FOUNDRY_WRITE_ENABLED + Write generate_loot Generate random loot for encounters Write generate_npc Generate a random NPC with stats and background Read diagnose_errors Stub: returns raw logs without analysis. Full diagnostic logic is tracked in 133 and not y Read get_actor_details Get detailed information about a specific actor Read get_chat_messages Get recent chat messages from the game

All 25 FoundryVTT MCP Server tools →

Write tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about update_actor_attributes

What does the update_actor_attributes tool do? +

Update attributes on an actor. It is categorised as a Write tool in the FoundryVTT MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on update_actor_attributes? +

Register the FoundryVTT MCP Server MCP server in PolicyLayer and add a rule for update_actor_attributes: 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.

What risk level is update_actor_attributes? +

update_actor_attributes is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit update_actor_attributes? +

Yes. Add a rate_limit block to the update_actor_attributes 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.

How do I block update_actor_attributes completely? +

Set action: deny in the PolicyLayer policy for update_actor_attributes. 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.

What MCP server provides update_actor_attributes? +

update_actor_attributes 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.

Enforce policy on every FoundryVTT MCP Server tool call.

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.

CHECK YOUR STACK →