Subscribe/Unsubscribe to Futu real-time quote updates.
AI agents call subscribe_quote to retrieve information from Stock Data MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Despite the word 'subscribe,' this tool's function is to establish or terminate a connection to real-time market data feeds. No data is created, modified, or destroyed in the underlying system; the tool merely controls the AI agent's access to existing quote information. This is fundamentally a Read operation with subscription management as the mechanism.
From the tool's definition Tool description states 'Subscribe/Unsubscribe to Futu real-time quote updates' - this is a subscription management operation for receiving data streams, not creating persistent data, modifying records, executing commands, or deleting resources.
Attacks that exploit this kind of access
Subscribe/Unsubscribe to Futu real-time quote updates. It is categorised as a Read tool in the Stock Data MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Stock Data MCP Server MCP server in PolicyLayer and add a rule for subscribe_quote: 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 Stock Data MCP Server. Nothing to install.
subscribe_quote 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 subscribe_quote 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 subscribe_quote. 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.
subscribe_quote is provided by the Stock Data MCP Server MCP server (wallacetju/mystockmcp). 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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