rpc_mempool_info

THE RISK

Low Risk

Why rpc_mempool_info needs a policy

This is a read-only query into Bitcoin mempool state. It retrieves informational data about network conditions and fee metrics without modifying, executing operations, or committing financial transactions. Even in the context of a blockchain API, this is classified as Read since it merely observes and returns data.

From the tool's definition Tool description states it 'Returns size, memory usage, fee thresholds, and Replace-By-Fee (RBF) state' — these are query/retrieval operations with no side effects. The verb 'Returns' indicates data fetching only.

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

POLICY

How to control rpc_mempool_info

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 rpc_mempool_info:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "rpc_mempool_info": {}
  }
}

rpc_mempool_info is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register Maestro 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.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about rpc_mempool_info

What does the rpc_mempool_info tool do? +

Returns size, memory usage, fee thresholds, and Replace-By-Fee (RBF) state. Useful for gauging current congestion and planning fees accordingly. It is categorised as a Read tool in the Maestro MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on rpc_mempool_info? +

Register the Maestro MCP Server MCP server in PolicyLayer and add a rule for rpc_mempool_info: 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.

What risk level is rpc_mempool_info? +

rpc_mempool_info is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit rpc_mempool_info? +

Yes. Add a rate_limit block to the rpc_mempool_info 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 rpc_mempool_info completely? +

Set action: deny in the PolicyLayer policy for rpc_mempool_info. 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 rpc_mempool_info? +

rpc_mempool_info 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.

Enforce policy on every Maestro MCP Server tool call.

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.

CHECK YOUR STACK →