Returns the current balance of an ERC-20 token of an address.
AI agents call account__tokenbalance to retrieve information from Etherscan MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves blockchain data (token balance) without creating, modifying, deleting, or executing anything. It is a pure Read operation with minimal blast radius - an AI agent querying token balances cannot cause financial harm or irreversible changes. The low severity reflects that this is informational access only.
From the tool's definition Tool returns current balance of an ERC-20 token - a read-only query operation. Description explicitly uses 'Returns' indicating data retrieval with no side effects. No modification, deletion, or external execution is performed.
Documented attack patterns abuse exactly the kind of access account__tokenbalance gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Etherscan MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for account__tokenbalance:
{
"version": "1",
"default": "deny",
"tools": {
"account__tokenbalance": {}
}
}account__tokenbalance 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 current balance of an ERC-20 token of an address. It is categorised as a Read tool in the Etherscan MCP MCP Server, which means it retrieves data without modifying state.
Register the Etherscan MCP server in PolicyLayer and add a rule for account__tokenbalance: 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 Etherscan MCP. Nothing to install.
account__tokenbalance 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 account__tokenbalance 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 account__tokenbalance. 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.
account__tokenbalance is provided by the Etherscan MCP server (xiaok/etherscan-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Etherscan MCP, 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.
56 Etherscan MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.