Transfer between two Santander accounts (TEF / mesma instituição). Settles instantly and is fee-free for most covenants.
AI agents use transfer_internal to commit financial operations through Mcp Ap2 — usually the final step of a payment, billing, or trading workflow. A call moves real money.
This tool moves money between accounts. Regardless of whether transfers are between internal accounts or to external parties, any tool that executes fund transfers without explicit mention of human authorization or transaction limits poses critical financial risk. An AI agent with access could drain accounts, redirect funds, or commit unauthorized transfers.
From the tool's definition Tool explicitly 'Transfer between two Santander accounts' with no approval gate mentioned; server context is 'Google's Agent-to-Agent Payment Protocol (authorization, audit, trust)'; description emphasizes 'settles instantly and is fee-free', confirming…
Documented attack patterns abuse exactly the kind of access transfer_internal gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mcp Ap2, and nothing reaches the server without passing your rules. This is the rule we recommend for transfer_internal:
{
"version": "1",
"default": "deny",
"tools": {
"transfer_internal": {
"deny_if": [
{
"conditions": [],
"on_deny": "Requires human approval."
}
]
}
}
} Any call to transfer_internal is blocked until a human approves it. The rest of the server keeps working.
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Transfer between two Santander accounts (TEF / mesma instituição). Settles instantly and is fee-free for most covenants. It is categorised as a Financial tool in the Mcp Ap2 MCP Server, which means it involves financial transactions. Block by default and require explicit approval.
Register the Mcp Ap2 MCP server in PolicyLayer and add a rule for transfer_internal: 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 Ap2. Nothing to install.
transfer_internal is a Financial tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the transfer_internal 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.
Set action: deny in the PolicyLayer policy for transfer_internal. 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.
transfer_internal is provided by the Mcp Ap2 MCP server (@codespar/mcp-ap2). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Mcp Ap2, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
1300 Mcp Ap2 tools catalogued and risk-classified — across an index of 43,000+ MCP servers.