AI agents call get_historical_stock_prices to retrieve information from MCP Yahoo Finance without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves historical stock price data without side effects. It queries and returns financial information but does not create, modify, delete, or execute transactions. The absence of a tool description is offset by strong contextual evidence from the server purpose and naming pattern of sibling tools, all of which are read-only financial data accessors.
From the tool's definition Tool name 'get_historical_stock_prices' indicates data retrieval. Server description states it 'Provides tools to get financial data (stock prices, company information)' with no mention of modification, deletion, or financial transactions.
Documented attack patterns abuse exactly the kind of access get_historical_stock_prices gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Yahoo Finance, and nothing reaches the server without passing your rules. This is the rule we recommend for get_historical_stock_prices:
{
"version": "1",
"default": "deny",
"tools": {
"get_historical_stock_prices": {}
}
}get_historical_stock_prices is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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get_historical_stock_prices. It is categorised as a Read tool in the MCP Yahoo Finance MCP Server, which means it retrieves data without modifying state.
Register the MCP Yahoo Finance MCP server in PolicyLayer and add a rule for get_historical_stock_prices: 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 MCP Yahoo Finance. Nothing to install.
get_historical_stock_prices 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 get_historical_stock_prices 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 get_historical_stock_prices. 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.
get_historical_stock_prices is provided by the MCP Yahoo Finance MCP server (leoncuhk/mcp-yahoo-finance). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP Yahoo Finance, 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.
12 MCP Yahoo Finance tools catalogued and risk-classified — across an index of 43,000+ MCP servers.