AI agents call concat_hex as a supporting operation in BNB Chain MCP workflows.
This tool performs a pure data manipulation operation — joining hex strings — with no side effects, no data retrieval, no execution, and no financial implications. It is a utility/encoding helper that operates entirely locally on provided inputs.
From the tool's definition Concatenate multiple hex strings together
Documented attack patterns abuse exactly the kind of access concat_hex 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 concat_hex:
{
"version": "1",
"default": "deny",
"tools": {
"concat_hex": {
"limits": [
{
"counter": "concat_hex_rate",
"window": "minute",
"max": 60,
"scope": "grant"
}
]
}
}
}concat_hex gets a rate cap, and everything else on the server is denied unless you say otherwise.
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Concatenate multiple hex strings together. It is categorised as a Other tool in the BNB Chain MCP MCP Server, which means it performs auxiliary operations.
Register the BNB Chain MCP server in PolicyLayer and add a rule for concat_hex: 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.
concat_hex is a Other tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the concat_hex 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 concat_hex. 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.
concat_hex 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.
Free to start. No card required.
1240 BNB Chain MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.