Transfer vault shares from one account to another (must be parent→sub-account)
AI agents use yault_transfer to commit financial operations through Yault AESP — usually the final step of a payment, billing, or trading workflow. A call moves real money.
This tool moves value (vault shares representing cryptocurrency assets) between accounts. Even though it is described as 'policy-gated' and 'under human control', the core function is a financial transfer that commits assets from one party to another. This is a Financial category tool due to the movement of monetary value.
From the tool's definition Tool name includes 'transfer' and description explicitly states 'Transfer vault shares from one account to another'. Vault operations involve cryptocurrency/assets per server description ('Crypto payments for the agent economy').
Attacks that exploit this kind of access
Transfer vault shares from one account to another (must be parent→sub-account). It is categorised as a Financial tool in the Yault AESP MCP Server, which means it involves financial transactions. Block by default and require explicit approval.
Register the Yault AESP MCP server in PolicyLayer and add a rule for yault_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 Yault AESP. Nothing to install.
yault_transfer 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 yault_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.
Set action: deny in the PolicyLayer policy for yault_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.
yault_transfer is provided by the Yault AESP MCP server (@yault/aesp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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