bn_close_listen_key · Node2flow/binance MCP: Risk & Policy

WHAT IT DOES

What bn_close_listen_key does on Node2flow/binance

AI agents invoke bn_close_listen_key to trigger actions in Node2flow/binance. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why bn_close_listen_key needs a policy

This tool terminates an active user data stream by invalidating a listen key. It is an external operation with a real side effect (stream termination), but it is not strictly destructive to persistent data — streams can be recreated. It falls under Execute as it triggers an external operation on Binance's infrastructure.

From the tool's definition Close/invalidate a listen key. The associated user data stream will be terminated.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

bn_close_listen_key Rate-limited

bn_close_listen_key stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "bn_close_listen_key": {
      "limits": [
        {
          "counter": "bn_close_listen_key_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Node2flow/binance, so you can run agents against it safely.

FAQ

Questions about bn_close_listen_key

What does the bn_close_listen_key tool do? +

Close/invalidate a listen key. The associated user data stream will be terminated. It is categorised as a Execute tool in the Node2flow/binance MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on bn_close_listen_key? +

Register the Node2flow/binance MCP server in PolicyLayer and add a rule for bn_close_listen_key: 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 Node2flow/binance. Nothing to install.

What risk level is bn_close_listen_key? +

bn_close_listen_key is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit bn_close_listen_key? +

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

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

bn_close_listen_key is provided by the Node2flow/binance MCP server (node2flow-th/binance-mcp-community). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.