清理表以回收空间
AI agents call vacuum to retrieve information from PostGIS Yukon MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Even though vacuum only reads data, uncontrolled read access leaks sensitive information and racks up API costs — an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Attacks that exploit this kind of access
清理表以回收空间. It is categorised as a Read tool in the PostGIS Yukon MCP MCP Server, which means it retrieves data without modifying state.
Register the PostGIS Yukon MCP server in PolicyLayer and add a rule for vacuum: 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 PostGIS Yukon MCP. Nothing to install.
vacuum 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 vacuum 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 vacuum. 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.
vacuum is provided by the PostGIS Yukon MCP server (zmgiser/postgis_yukon_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.