Get the execution plan for a SQL query to analyze performance
AI agents call explain_query to retrieve information from Vertica MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns metadata (execution plans) about how queries would execute, which is a read operation. However, it receives 'medium' severity because a malicious actor could abuse query plans to extract schema information about sensitive tables or identify performance bottlenecks/vulnerabilities in database structure, or use it for reconnaissance before launching more damaging attacks.
From the tool's definition Tool description states it retrieves an 'execution plan for a SQL query' without modifying data. The server provides 'schema inspection, database documentation, and data export capabilities' indicating read-centric operations.
Attacks that exploit this kind of access
Get the execution plan for a SQL query to analyze performance. It is categorised as a Read tool in the Vertica MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Vertica MCP Server MCP server in PolicyLayer and add a rule for explain_query: 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 Vertica MCP Server. Nothing to install.
explain_query 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 explain_query 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 explain_query. 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.
explain_query is provided by the Vertica MCP Server MCP server (smith-nathanh/vertica-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
explain_query is one line of Vertica MCP Server's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
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