Get Level II market data for a stock (Gold subscription required)
AI agents call stock_level2_data to retrieve information from Open Paper Trading MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves market data without altering any state, creating obligations, or executing external operations. It is a pure read operation. Severity is low because unauthorized access to Level II market data has minimal blast radius—it cannot be weaponized to cause financial harm, delete data, or execute unwanted operations.
From the tool's definition Tool name includes 'get' action (implied by 'Get Level II market data') and description explicitly states it retrieves market data. No side effects or modifications occur—it only queries and returns real-time market information.
Documented attack patterns abuse exactly the kind of access stock_level2_data gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Open Paper Trading MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for stock_level2_data:
{
"version": "1",
"default": "deny",
"tools": {
"stock_level2_data": {}
}
}stock_level2_data is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Get Level II market data for a stock (Gold subscription required). It is categorised as a Read tool in the Open Paper Trading MCP MCP Server, which means it retrieves data without modifying state.
Register the Open Paper Trading MCP server in PolicyLayer and add a rule for stock_level2_data: 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 Open Paper Trading MCP. Nothing to install.
stock_level2_data 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 stock_level2_data 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 stock_level2_data. 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.
stock_level2_data is provided by the Open Paper Trading MCP server (open-agent-tools/open-paper-trading-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Open Paper Trading MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
44 Open Paper Trading MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.