Returns the total balance in satoshis held at the specified address or script pubkey by summing all unspent outputs (UTXOs). In addition to confirmed transactions, mempool endpoints return data which reflects pending transactions in some number of
AI agents call mempool_satoshi_balance_by_address to retrieve information from Maestro MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves blockchain balance data for a given address without modifying, deleting, or executing any operations. It is a read-only query operation that has no side effects on the blockchain or wallet state. The mention of mempool data reflects pending transactions is standard blockchain indexing, not an action taken by the tool.
From the tool's definition Returns the total balance in satoshis...by summing all unspent outputs (UTXOs). No side effects; pure data retrieval of balance information.
Documented attack patterns abuse exactly the kind of access mempool_satoshi_balance_by_address gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Maestro MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for mempool_satoshi_balance_by_address:
{
"version": "1",
"default": "deny",
"tools": {
"mempool_satoshi_balance_by_address": {}
}
} mempool_satoshi_balance_by_address is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Returns the total balance in satoshis held at the specified address or script pubkey by summing all unspent outputs (UTXOs). In addition to confirmed transactions, mempool endpoints return data which reflects pending transactions in some number of. It is categorised as a Read tool in the Maestro MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Maestro MCP Server MCP server in PolicyLayer and add a rule for mempool_satoshi_balance_by_address: 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 Maestro MCP Server. Nothing to install.
mempool_satoshi_balance_by_address 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 mempool_satoshi_balance_by_address 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 mempool_satoshi_balance_by_address. 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.
mempool_satoshi_balance_by_address is provided by the Maestro MCP Server MCP server (maestro-org/maestro-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Maestro MCP Server, 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.
117 Maestro MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.