Check the vault balance for a wallet address
AI agents call yault_check_balance to retrieve information from Yault AESP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves balance information without modifying, deleting, or moving funds. It is a read-only query on financial data. While it accesses sensitive information (wallet balances), it poses minimal risk because it neither executes transactions, transfers funds, nor modifies state.
From the tool's definition Tool description states 'Check the vault balance for a wallet address' — a pure query operation with no side effects.
Attacks that exploit this kind of access
Check the vault balance for a wallet address. It is categorised as a Read tool in the Yault AESP MCP Server, which means it retrieves data without modifying state.
Register the Yault AESP MCP server in PolicyLayer and add a rule for yault_check_balance: 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_check_balance is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the yault_check_balance 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_check_balance. 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_check_balance 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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