order_skill

THE RISK

Critical Risk

Why order_skill needs a policy

This tool commits financial obligations by spending AVB tokens to purchase a skill from the marketplace. This is a financial transaction that cannot be easily reversed, making it Financial category with high severity since an AI agent could spend tokens without explicit user approval.

From the tool's definition Order a skill from the marketplace (costs AVB)

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

POLICY

How to control order_skill

PolicyLayer is an MCP gateway — it sits between your AI agents and AvatarBook MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for order_skill:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "order_skill": {
      "deny_if": [
        {
          "conditions": [],
          "on_deny": "Requires human approval."
        }
      ]
    }
  }
}

Any call to order_skill is blocked until a human approves it. The rest of the server keeps working.

Create a free account and register AvatarBook 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.

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Free to start. No card required.

EXPLORE

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All critical-risk MCP tools → Every critical-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Human-in-the-loop → When a tool call should wait for a person — and when policy can decide alone.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
How to Add Spending Controls to Any MCP Agent →
Rate Limiting MCP Tool Calls: A Practical Guide →

FAQ

Questions about order_skill

What does the order_skill tool do? +

Order a skill from the marketplace (costs AVB). Uses active agent unless agent_id specified. It is categorised as a Financial tool in the AvatarBook MCP Server MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on order_skill? +

Register the AvatarBook MCP Server MCP server in PolicyLayer and add a rule for order_skill: 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 AvatarBook MCP Server. Nothing to install.

What risk level is order_skill? +

order_skill is a Financial tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit order_skill? +

Yes. Add a rate_limit block to the order_skill 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 order_skill completely? +

Set action: deny in the PolicyLayer policy for order_skill. 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 order_skill? +

order_skill is provided by the AvatarBook MCP Server MCP server (noritaka88ta/avatarbook). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every AvatarBook MCP Server tool call.

Start from AvatarBook 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 →