create_subaccount · Mcp Kraken MCP: Risk & Policy

WHAT IT DOES

What create_subaccount does on Mcp Kraken

AI agents use create_subaccount to create or update resources in Mcp Kraken — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Mcp Kraken environment.

WHY IT NEEDS A POLICY

Why create_subaccount needs a policy

This tool creates a new sub-account, which is a reversible write operation that modifies account structure and configuration. It does not delete data (not Destructive), execute arbitrary code (not Execute), or move funds (not Financial). While it has moderate blast radius in a multi-account cryptocurrency context, it is fundamentally a Write operation.

From the tool's definition Tool description states 'Create a new sub-account' - a create operation that modifies account structure. Server context shows this is a Kraken cryptocurrency exchange API with 'account management' capabilities.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_subaccount Rate-limited

create_subaccount 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.

View as policy code

policy.json

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

LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about create_subaccount

What does the create_subaccount tool do? +

Create a new sub-account. It is categorised as a Write tool in the Mcp Kraken MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_subaccount? +

Register the Mcp Kraken MCP server in PolicyLayer and add a rule for create_subaccount: 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 Mcp Kraken. Nothing to install.

What risk level is create_subaccount? +

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

Can I rate-limit create_subaccount? +

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

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

create_subaccount is provided by the Mcp Kraken MCP server (xavierbeheydt/mcp-kraken). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.