Trace where a parameter or field such as userId is used across path parameters, query parameters, request bodies, and response bodies.
AI agents call trace_parameter_usage to retrieve information from MCP OpenAPI Discovery without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool performs static analysis of OpenAPI/Swagger specifications to identify where a given parameter is used. This is a read-only operation that retrieves and analyzes existing API metadata without side effects. No data is created, modified, deleted, or executed. It functions as a documentation inspection tool, similar to a search or query operation within specifications.
From the tool's definition Tool traces parameter usage across API specifications (path parameters, query parameters, request bodies, response bodies) - a purely informational operation that inspects and queries API documentation without modifying or executing any operations.
Attacks that exploit this kind of access
Trace where a parameter or field such as userId is used across path parameters, query parameters, request bodies, and response bodies. It is categorised as a Read tool in the MCP OpenAPI Discovery MCP Server, which means it retrieves data without modifying state.
Register the MCP OpenAPI Discovery MCP server in PolicyLayer and add a rule for trace_parameter_usage: 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 OpenAPI Discovery. Nothing to install.
trace_parameter_usage 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 trace_parameter_usage 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 trace_parameter_usage. 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.
trace_parameter_usage is provided by the MCP OpenAPI Discovery MCP server (rekl0w/mcp-openapi-discovery). 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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