get_bollinger_bands
AI agents call get_bollinger_bands to retrieve information from MCP YFinance Stock Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Bollinger Bands is a passive technical analysis calculation derived from historical stock data. The tool retrieves or computes an indicator without modifying data, executing external operations, or causing side effects. This places it firmly in the Read category with low severity—an AI misuse would at worst retrieve unwanted data, with no destructive or financial consequences.
From the tool's definition Tool name 'get_bollinger_bands' indicates data retrieval. No description provided, but Bollinger Bands is a standard technical analysis indicator that reads and calculates values from historical price data.
Attacks that exploit this kind of access
get_bollinger_bands. It is categorised as a Read tool in the MCP YFinance Stock Server MCP Server, which means it retrieves data without modifying state.
Register the MCP YFinance Stock Server MCP server in PolicyLayer and add a rule for get_bollinger_bands: 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 YFinance Stock Server. Nothing to install.
get_bollinger_bands 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_bollinger_bands 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_bollinger_bands. 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_bollinger_bands is provided by the MCP YFinance Stock Server MCP server (sauniket/mcp-yfinance-server). 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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