AI agents use unsubscribe_from_stream to create or update resources in Binance MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Binance MCP Server environment.
Unsubscribing from a WebSocket stream modifies the state of an active subscription by terminating it, which is a reversible write-like operation (you can re-subscribe). It does not delete data, execute code, or move money. The blast radius is low — the worst outcome is losing a live data feed, which can be restored by re-subscribing.
From the tool's definition Unsubscribe from a WebSocket stream
Documented attack patterns abuse exactly the kind of access unsubscribe_from_stream gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Binance MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for unsubscribe_from_stream:
{
"version": "1",
"default": "deny",
"tools": {
"unsubscribe_from_stream": {
"limits": [
{
"counter": "unsubscribe_from_stream_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}unsubscribe_from_stream stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Unsubscribe from a WebSocket stream. It is categorised as a Write tool in the Binance MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Binance MCP Server MCP server in PolicyLayer and add a rule for unsubscribe_from_stream: 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 Binance MCP Server. Nothing to install.
unsubscribe_from_stream is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the unsubscribe_from_stream 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 unsubscribe_from_stream. 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.
unsubscribe_from_stream is provided by the Binance MCP Server MCP server (tienan92it/binance-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Binance MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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29 Binance MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.