AI agents call eth_balance to retrieve information from Crypto Multi-MCP Hub without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves Ethereum balance data, which is a read-only query with no side effects. No data is created, modified, deleted, or financial transactions are initiated. The lack of a description lowers confidence slightly, but the name and server context strongly suggest a simple balance lookup.
From the tool's definition Tool name 'eth_balance' indicates a balance query operation. Given the server context of crypto operations and sibling tools like 'erc20_balance' and 'coin_info', this retrieves account balance data without modification.
Documented attack patterns abuse exactly the kind of access eth_balance gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Crypto Multi-MCP Hub, and nothing reaches the server without passing your rules. This is the rule we recommend for eth_balance:
{
"version": "1",
"default": "deny",
"tools": {
"eth_balance": {}
}
}eth_balance is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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eth_balance. It is categorised as a Read tool in the Crypto Multi-MCP Hub MCP Server, which means it retrieves data without modifying state.
Register the Crypto Multi-MCP Hub MCP server in PolicyLayer and add a rule for eth_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 Crypto Multi-MCP Hub. Nothing to install.
eth_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 eth_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 eth_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.
eth_balance is provided by the Crypto Multi-MCP Hub MCP server (pellenybe/crypto-mcp-server---by-corax-colab). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Crypto Multi-MCP Hub, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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48 Crypto Multi-MCP Hub tools catalogued and risk-classified — across an index of 43,000+ MCP servers.