Check if an address is a smart contract or an externally owned account (EOA)
AI agents call is_contract to retrieve information from BNB Chain MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool is purely informational, querying blockchain data to determine account type. It has no side effects, cannot execute code, modify state, or trigger financial transactions. This is a straightforward read operation with minimal risk if misused, as it only exposes publicly available account classification data.
From the tool's definition Tool performs a query operation: 'Check if an address is a smart contract or an externally owned account (EOA)'. This retrieves blockchain state information without modifying or executing anything.
Documented attack patterns abuse exactly the kind of access is_contract gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and BNB Chain MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for is_contract:
{
"version": "1",
"default": "deny",
"tools": {
"is_contract": {}
}
}is_contract is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Check if an address is a smart contract or an externally owned account (EOA). It is categorised as a Read tool in the BNB Chain MCP MCP Server, which means it retrieves data without modifying state.
Register the BNB Chain MCP server in PolicyLayer and add a rule for is_contract: 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 BNB Chain MCP. Nothing to install.
is_contract 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 is_contract 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 is_contract. 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.
is_contract is provided by the BNB Chain MCP server (nirholas/bnbchain-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 1240 BNB Chain MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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1240 BNB Chain MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.