AI agents call get_stock_bars to retrieve information from Alpaca without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves historical stock price information (bars/candles), which is a read-only operation with no side effects. While the server enables trading operations, this specific tool follows the pattern of other data-retrieval tools like 'get_account_info', 'get_all_assets', and 'get_asset_info' on the same server.
From the tool's definition Tool name 'get_stock_bars' indicates data retrieval of historical price bar data for stocks. No description provided, but the naming convention and context within a trading API server strongly suggest this is a query operation that retrieves time-series…
Attacks that exploit this kind of access
get_stock_bars. It is categorised as a Read tool in the Alpaca MCP Server, which means it retrieves data without modifying state.
Register the Alpaca MCP server in PolicyLayer and add a rule for get_stock_bars: 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 Alpaca. Nothing to install.
get_stock_bars 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_stock_bars 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_stock_bars. 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_stock_bars is provided by the Alpaca MCP server (mfoster5303-1/alpaca-mcp-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.
Teams ship this data inside their own products. See what a licence covers →