Returns a list of ERC-721 token balances
AI agents call getERC721Balance to retrieve information from Somnia 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 ERC-721 token balance information from the Somnia blockchain without modifying, deleting, or executing any state-changing operations. It has no financial impact, does not execute code, and cannot delete or modify data. The blast radius of misuse is minimal—an attacker could only enumerate token holdings, which is typically public blockchain data anyway.
From the tool's definition Tool name 'getERC721Balance' and description 'Returns a list of ERC-721 token balances' indicate a retrieval operation with no side effects. The verb 'Returns' and context of querying blockchain data confirm this is a read-only operation.
Attacks that exploit this kind of access
Returns a list of ERC-721 token balances. It is categorised as a Read tool in the Somnia MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Somnia MCP Server MCP server in PolicyLayer and add a rule for getERC721Balance: 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 Somnia MCP Server. Nothing to install.
getERC721Balance 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 getERC721Balance 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 getERC721Balance. 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.
getERC721Balance is provided by the Somnia MCP Server MCP server (vastavikadi/somnia-mcp). 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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