Top stock movers — gainers (largest % up), losers (largest % down), or active
AI agents call get_top_movers to retrieve information from Signal8 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 existing financial market data to identify stocks with largest price movements. It has no side effects—no data is created, modified, deleted, or transacted. The severity is low because the data retrieved is public market information that does not enable direct financial harm; an AI agent could misuse it only by providing misleading analysis based on the data, not by the tool itself.
From the tool's definition Tool name 'get_top_movers' and description 'Top stock movers — gainers (largest % up), losers (largest % down), or active' indicate retrieval of publicly available market data (stock price movements).
Attacks that exploit this kind of access
Top stock movers — gainers (largest % up), losers (largest % down), or active. It is categorised as a Read tool in the Signal8 MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Signal8 MCP Server MCP server in PolicyLayer and add a rule for get_top_movers: 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 Signal8 MCP Server. Nothing to install.
get_top_movers 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_top_movers 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_top_movers. 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_top_movers is provided by the Signal8 MCP Server MCP server (signal8ai/signal8-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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