screen_stocks
AI agents call screen_stocks to retrieve information from yfinance MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Stock screening is a read-only query operation that filters and retrieves stock data based on criteria. It has no side effects, does not modify data, and does not execute external operations or trigger financial transactions. The broader context of the yfinance server, which is a data provider, confirms this is a retrieval tool.
From the tool's definition Tool name 'screen_stocks' combined with sibling tools that are all retrieval-focused (get_historical_data, get_earnings, get_dividends, get_financials, get_analyst_ratings, etc.).
Attacks that exploit this kind of access
screen_stocks. It is categorised as a Read tool in the yfinance MCP Server MCP Server, which means it retrieves data without modifying state.
Register the yfinance MCP Server MCP server in PolicyLayer and add a rule for screen_stocks: 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 yfinance MCP Server. Nothing to install.
screen_stocks 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 screen_stocks 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 screen_stocks. 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.
screen_stocks is provided by the yfinance MCP Server MCP server (torosent/yfinance-mcp). 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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