Query historical data for Funds (ETF preferred).
AI agents call query_fund_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 financial market data (fund/ETF historical information) without side effects. It performs a simple read operation analogous to a database SELECT query. No data is created, modified, deleted, or financially transacted. The blast radius of misuse is minimal—an attacker could only gather market intelligence, not manipulate markets or accounts.
From the tool's definition Tool name 'query_fund_data' with description 'Query historical data for Funds (ETF preferred)' indicates data retrieval. The verb 'Query' and context of 'historical data' confirm read-only operation with no modification, deletion, or execution capability.
Attacks that exploit this kind of access
Query historical data for Funds (ETF preferred). 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_fund_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_fund_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_fund_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_fund_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_fund_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.
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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