hl_create_sub_account

THE RISK

Critical Risk

Why hl_create_sub_account needs a policy

Creating a sub-account on Hyperliquid (a perpetuals/DeFi exchange) establishes a new financial account entity that can hold funds and execute trades. On a platform with perp trading and financial operations, sub-accounts are used to segregate funds and trading activity.

From the tool's definition Create a new Hyperliquid sub-account — on a server described as handling 'transfers, token management, DeFi (swap, lend, stake, bridge, perp)' with spending limits and financial operations

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

POLICY

How to control hl_create_sub_account

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

policy.json

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

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

Create a free account and register Waiaas — 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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EXPLORE

Related tools and policies

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Go deeper

Critical-risk tools in Waiaas → Every critical-risk tool this server exposes, in one view.
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 hl_create_sub_account

What does the hl_create_sub_account tool do? +

Create a new Hyperliquid sub-account. It is categorised as a Financial tool in the Waiaas MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on hl_create_sub_account? +

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

What risk level is hl_create_sub_account? +

hl_create_sub_account 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 hl_create_sub_account? +

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

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

hl_create_sub_account is provided by the Waiaas MCP server (minhoyoo-iotrust/waiaas). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Waiaas tool call.

Start from Waiaas, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

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