Get native token balance for an EVM address on any supported network
AI agents call getEvmBalance to retrieve information from Web3 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 data (native token balance) from the blockchain without modifying, executing code, or committing any financial transactions. It is a read-only query operation with minimal blast radius if misused by an AI agent — worst case, an agent queries balances it should not have access to, a data confidentiality concern rather than a security or safety risk.
From the tool's definition Tool name is 'getEvmBalance' and description states 'Get native token balance for an EVM address on any supported network' — purely a query operation that retrieves balance information with no side effects.
Documented attack patterns abuse exactly the kind of access getEvmBalance gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Web3 MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for getEvmBalance:
{
"version": "1",
"default": "deny",
"tools": {
"getEvmBalance": {}
}
}getEvmBalance is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get native token balance for an EVM address on any supported network. It is categorised as a Read tool in the Web3 MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Web3 MCP Server MCP server in PolicyLayer and add a rule for getEvmBalance: 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 Web3 MCP Server. Nothing to install.
getEvmBalance 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 getEvmBalance 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 getEvmBalance. 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.
getEvmBalance is provided by the Web3 MCP Server MCP server (strangelove-ventures/web3-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 55 Web3 MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
55 Web3 MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.