AI agents call getFeeData to retrieve information from MCP Ethers Wallet without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool name 'getFeeData' indicates retrieval of blockchain fee information, which is a read operation with no side effects. However, within the context of an Ethereum wallet server where an LLM could use this data to make transaction decisions, severity is rated medium rather than low—an attacker could use fee data queries to enumerate blockchain state or inform transaction timing attacks.
From the tool's definition Tool name 'getFeeData' with no description provided. Given the server context (Ethereum wallet interaction), this most likely retrieves gas fee or transaction cost data from the blockchain.
Documented attack patterns abuse exactly the kind of access getFeeData gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Ethers Wallet, and nothing reaches the server without passing your rules. This is the rule we recommend for getFeeData:
{
"version": "1",
"default": "deny",
"tools": {
"getFeeData": {}
}
}getFeeData is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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getFeeData. It is categorised as a Read tool in the MCP Ethers Wallet MCP Server, which means it retrieves data without modifying state.
Register the MCP Ethers Wallet MCP server in PolicyLayer and add a rule for getFeeData: 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 Ethers Wallet. Nothing to install.
getFeeData 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 getFeeData 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 getFeeData. 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.
getFeeData is provided by the MCP Ethers Wallet MCP server (crazyrabbitltc/mcp-ethers-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP Ethers Wallet, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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69 MCP Ethers Wallet tools catalogued and risk-classified — across an index of 43,000+ MCP servers.