Query historical data for indices (e.g.,
AI agents call query_index_data to retrieve information from Stock Data 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 historical index data for analysis purposes. It has no side effects, does not modify data, execute code, delete records, or move money. It is purely informational and read-only. Severity is low because misuse would at worst provide misleading financial information to an AI agent, but cannot cause direct operational or financial harm through the tool itself.
From the tool's definition Tool name 'query_index_data' and description 'Query historical data for indices' indicate retrieval of financial data without modification or execution.
Attacks that exploit this kind of access
Query historical data for indices (e.g.,. It is categorised as a Read tool in the Stock Data MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Stock Data MCP Server MCP server in PolicyLayer and add a rule for query_index_data: 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 Stock Data MCP Server. Nothing to install.
query_index_data 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 query_index_data 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 query_index_data. 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.
query_index_data is provided by the Stock Data MCP Server MCP server (xj-bear/stockdata-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
query_index_data is one line of Stock Data MCP Server's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
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