Get available option expiration dates for a ticker
AI agents call get_option_expiration_dates to retrieve information from Yahoo Finance MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries financial market data (option expiration dates) with no side effects, capability to execute trades, modify data, or trigger irreversible actions. It is informational only, consistent with the Read category. Severity is low because misuse would only provide market information to an AI agent without enabling financial transactions or market manipulation.
From the tool's definition Tool name 'get_option_expiration_dates' and description 'Get available option expiration dates for a ticker' indicate data retrieval with no modification or execution. Returns metadata about available expiration dates for options on a given ticker.
Attacks that exploit this kind of access
Get available option expiration dates for a ticker. It is categorised as a Read tool in the Yahoo Finance MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Yahoo Finance MCP Server MCP server in PolicyLayer and add a rule for get_option_expiration_dates: 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 Yahoo Finance MCP Server. Nothing to install.
get_option_expiration_dates 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_option_expiration_dates 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_option_expiration_dates. 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_option_expiration_dates is provided by the Yahoo Finance MCP Server MCP server (refself/yahoo-finance-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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