hl_sub_transfer

THE RISK

Critical Risk

Why hl_sub_transfer needs a policy

This tool moves money (USDC tokens) between accounts, which is a direct financial transaction. Even with the policy engine and spending limits mentioned in the server description, the tool's core function is to commit financial obligations and transfer value. This is the most severe risk category. The confidence is high because the description unambiguously describes a token transfer operation.

From the tool's definition Tool description explicitly states 'Transfer USDC between master account and sub-account'. USDC is a stablecoin with direct financial value.

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

POLICY

How to control hl_sub_transfer

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_sub_transfer:

policy.json

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

Any call to hl_sub_transfer 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

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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.
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FAQ

Questions about hl_sub_transfer

What does the hl_sub_transfer tool do? +

Transfer USDC between master account and 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_sub_transfer? +

Register the Waiaas MCP server in PolicyLayer and add a rule for hl_sub_transfer: 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_sub_transfer? +

hl_sub_transfer 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_sub_transfer? +

Yes. Add a rate_limit block to the hl_sub_transfer 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_sub_transfer completely? +

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

hl_sub_transfer 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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