The Williams %R (WILLR) is a momentum oscillator that measures the level of a security
AI agents call GetTimeSeriesWillR 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.
This tool retrieves and calculates financial market analysis data (Williams %R technical indicator) without creating, modifying, deleting, or executing any operations. It is a passive data query with no side effects. The low severity reflects that misuse would only result in retrieving analysis data, posing minimal risk.
From the tool's definition Tool name 'GetTimeSeriesWillR' uses 'Get' prefix and returns time series data for a technical indicator (Williams %R momentum oscillator).
Documented attack patterns abuse exactly the kind of access GetTimeSeriesWillR 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 GetTimeSeriesWillR:
{
"version": "1",
"default": "deny",
"tools": {
"GetTimeSeriesWillR": {}
}
}GetTimeSeriesWillR is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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The Williams %R (WILLR) is a momentum oscillator that measures the level 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 GetTimeSeriesWillR: 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.
GetTimeSeriesWillR 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 GetTimeSeriesWillR 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 GetTimeSeriesWillR. 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.
GetTimeSeriesWillR 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.