AI agents call stock_ratings 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 and displays analyst rating information about stocks. It performs no writes, deletes, executions, or financial transactions. The data retrieved is informational only and cannot be used to modify account state or execute trades directly. Even in a paper trading context where financial risk is eliminated, the tool itself only reads publicly available analyst data.
From the tool's definition Tool name 'stock_ratings' and description 'Get analyst ratings for a stock' indicate data retrieval with no side effects. The verb 'Get' and lack of any modification or execution language confirm this is a query-only operation.
Documented attack patterns abuse exactly the kind of access stock_ratings 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_ratings:
{
"version": "1",
"default": "deny",
"tools": {
"stock_ratings": {}
}
}stock_ratings is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get analyst ratings for a stock. 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_ratings: 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_ratings 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_ratings 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_ratings. 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_ratings 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.
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44 Open Paper Trading MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.