AI agents call stock_events 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 informational data about corporate events (dividends, earnings dates, splits, etc.) for a given stock. It performs no modifications, deletions, or executions—it simply queries and returns existing event data. The blast radius of misuse is minimal: an agent could request events for stocks it shouldn't have access to, but cannot cause financial harm, trigger trades, or modify account state.
From the tool's definition Tool name 'stock_events' and description 'Get corporate events for a stock' indicate a query/retrieval operation with no side effects. The verb 'Get' and the read-only nature of fetching event information confirms this is data retrieval.
Documented attack patterns abuse exactly the kind of access stock_events 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_events:
{
"version": "1",
"default": "deny",
"tools": {
"stock_events": {}
}
}stock_events is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get corporate events 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_events: 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_events 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_events 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_events. 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_events 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.