The Momentum (MOM) indicator measures the rate of change of a security
AI agents call GetTimeSeriesMom to retrieve information from Twelve Data MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
GetTimeSeriesMom is a query tool that returns calculated technical indicators based on historical market data. It performs no side effects, creates no data modifications, executes no arbitrary code, and involves no financial transactions. This is clearly a Read operation with low severity since misuse would only retrieve potentially stale or misinterpreted technical analysis data without operational impact.
From the tool's definition Tool retrieves and calculates the Momentum (MOM) indicator—a technical analysis metric measuring rate of change. The description explicitly states it 'measures' a property, indicating data retrieval and computation without modification of underlying data.
Documented attack patterns abuse exactly the kind of access GetTimeSeriesMom gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Twelve Data MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for GetTimeSeriesMom:
{
"version": "1",
"default": "deny",
"tools": {
"GetTimeSeriesMom": {}
}
}GetTimeSeriesMom is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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The Momentum (MOM) indicator measures the rate of change of a security. It is categorised as a Read tool in the Twelve Data MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Twelve Data MCP Server MCP server in PolicyLayer and add a rule for GetTimeSeriesMom: 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 Twelve Data MCP Server. Nothing to install.
GetTimeSeriesMom 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 GetTimeSeriesMom 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 GetTimeSeriesMom. 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.
GetTimeSeriesMom is provided by the Twelve Data MCP Server MCP server (twelvedata/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 186 Twelve Data MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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186 Twelve Data MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.