start_transfer

THE RISK

Critical Risk

Why start_transfer needs a policy

A tool that starts financial transfers commits financial obligations and moves money. This is the most severe category (Financial > Destructive > Execute > Write > Read). Even though the description is empty, the function name combined with the server's explicit banking context and presence of verify_transfer as a sibling tool makes the intent unambiguous.

From the tool's definition Tool name is 'start_transfer' on an MBBank server with description stating it 'providing monitoring and analytics capabilities for MBBank accounts.' Sibling tools include transaction and balance queries, indicating this server manages real financial accounts.

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

POLICY

How to control start_transfer

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

policy.json

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

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

Create a free account and register MBBank 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.

GATE THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More MBBank MCP Server tools

Financial verify_transfer verify_transfer Read get_balances Get the balance from all accounts in MB Bank. Read get_bank_list Get the list of banks and their corresponding bank codes. Read get_card_transactions get_card_transactions Read get_cards Get the cards associated with the MB Bank account. Read get_interest_rates Get the interest rates for savings accounts in MB Bank. Read get_saving_details get_saving_details Read get_savings Get the savings accounts associated with the MB Bank account.

All 11 MBBank MCP Server tools →

Financial tools on other servers

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Go deeper

Critical-risk tools in MBBank MCP Server → 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 start_transfer

What does the start_transfer tool do? +

start_transfer. It is categorised as a Financial tool in the MBBank MCP Server MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on start_transfer? +

Register the MBBank MCP Server MCP server in PolicyLayer and add a rule for start_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 MBBank MCP Server. Nothing to install.

What risk level is start_transfer? +

start_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 start_transfer? +

Yes. Add a rate_limit block to the start_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 start_transfer completely? +

Set action: deny in the PolicyLayer policy for start_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 start_transfer? +

start_transfer is provided by the MBBank MCP Server MCP server (thedtvn/mbbank-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every MBBank MCP Server tool call.

Start from MBBank 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 →