buy_item · Habitca MCP: Risk & Policy

WHAT IT DOES

What buy_item does on Habitca

AI agents use buy_item to commit financial operations through Habitca — usually the final step of a payment, billing, or trading workflow. A call moves real money.

WHY IT NEEDS A POLICY

Why buy_item needs a policy

This tool performs a purchase transaction, spending in-game currency (gold/gems) to acquire items. While it operates within the Habitica virtual economy rather than real money, it commits financial-equivalent obligations (resource expenditure) that may be irreversible. The 'buy' action directly consumes currency, making it Financial in category.

From the tool's definition Buy an item from a shop

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

buy_item Approval-gated

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

View as policy code

policy.json

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

GATE THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Habitca, so you can run agents against it safely.

FAQ

Questions about buy_item

What does the buy_item tool do? +

Buy an item from a shop. It is categorised as a Financial tool in the Habitca MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on buy_item? +

Register the Habitca MCP server in PolicyLayer and add a rule for buy_item: 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 Habitca. Nothing to install.

What risk level is buy_item? +

buy_item 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 buy_item? +

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

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

buy_item is provided by the Habitca MCP server (leon-jarvis1/habitca_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.