Get ERC20 token balance for an address.
AI agents call erc20_balance to retrieve information from Mcp Services without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries blockchain state to retrieve balance information for a given address. It performs no writes, deletions, code execution, or financial transactions. While it provides information about cryptocurrency holdings, it is purely informational and read-only, making it a Read category tool with low severity.
From the tool's definition Tool name 'erc20_balance' and description 'Get ERC20 token balance for an address' indicate a read-only query operation. The verb 'Get' and action 'balance' are retrieval operations with no side effects.
Attacks that exploit this kind of access
Get ERC20 token balance for an address. It is categorised as a Read tool in the Mcp Services MCP Server, which means it retrieves data without modifying state.
Register the Mcp Services MCP server in PolicyLayer and add a rule for erc20_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 Mcp Services. Nothing to install.
erc20_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 erc20_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 erc20_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.
erc20_balance is provided by the Mcp Services MCP server (san-npm/mcp-services). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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