getERC20Balance

THE RISK

Low Risk

Why getERC20Balance needs a policy

This tool retrieves blockchain data (token balance) without modifying state, executing code, or moving funds. It is a straightforward read operation on immutable ledger data.

From the tool's definition Tool name is 'getERC20Balance' and description states 'Get the ERC20 token balance of a wallet'—pure query operation with no side effects, no state modification, and no execution of external operations.

Documented attack patterns abuse exactly the kind of access getERC20Balance gives an agent:

POLICY

How to control getERC20Balance

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 getERC20Balance:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "getERC20Balance": {}
  }
}

getERC20Balance 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 MCP Ethers Wallet — 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

More MCP Ethers Wallet tools

Financial prepareERC1155BatchTransfer Prepare an ERC1155 batch transfer transaction for signing. Returns transaction data that c Financial safeBatchTransferERC1155 Safely transfer multiple tokens from the connected wallet to another address in a single t Financial safeTransferERC1155 Safely transfer tokens from the connected wallet to another address Financial safeTransferERC721 Safely transfer an NFT from the connected wallet to another address, with additional data Financial transferERC20 Transfer ERC20 tokens from the connected wallet to another address Financial transferERC721 Transfer an NFT from the connected wallet to another address Financial transferFromERC20 Transfer ERC20 tokens from one address to another (requires approval) Financial transferNFT transferNFT

All 69 MCP Ethers Wallet tools →

Read tools on other servers

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Go deeper

Roll out MCP under one policy → Per-person scoped tokens, one central policy, and full audit across every server your team connects.
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 →
PolicyLayer vs alternatives → How deterministic, per-call MCP policy compares with gateways, identity layers, and authorisation platforms.

FAQ

Questions about getERC20Balance

What does the getERC20Balance tool do? +

Get the ERC20 token balance of a wallet. It is categorised as a Read tool in the MCP Ethers Wallet MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on getERC20Balance? +

Register the MCP Ethers Wallet MCP server in PolicyLayer and add a rule for getERC20Balance: 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.

What risk level is getERC20Balance? +

getERC20Balance is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit getERC20Balance? +

Yes. Add a rate_limit block to the getERC20Balance 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 getERC20Balance completely? +

Set action: deny in the PolicyLayer policy for getERC20Balance. 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 getERC20Balance? +

getERC20Balance 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.

Enforce policy on every MCP Ethers Wallet tool call.

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.

CHECK YOUR STACK →