Aggregate the entire CMDB by class via the ServiceNow Aggregate API (/api/now/stats/cmdb_ci grouped by sys_class_name with counts). One call returns the shape of the whole CMDB: a count per CI class sorted by count descending, plus the grand total and number of populated classes.
AI agents call count_cis_by_class to retrieve information from ServiceNow MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Even though count_cis_by_class 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.
Risk signalsBulk/mass operation — affects multiple targets
Attacks that exploit this kind of access
Aggregate the entire CMDB by class via the ServiceNow Aggregate API (/api/now/stats/cmdb_ci grouped by sys_class_name with counts). One call returns the shape of the whole CMDB: a count per CI class sorted by count descending, plus the grand total and number of populated classes. It is categorised as a Read tool in the ServiceNow MCP Server MCP Server, which means it retrieves data without modifying state.
Register the ServiceNow MCP Server MCP server in PolicyLayer and add a rule for count_cis_by_class: 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 ServiceNow MCP Server. Nothing to install.
count_cis_by_class 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 count_cis_by_class 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 count_cis_by_class. 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.
count_cis_by_class is provided by the ServiceNow MCP Server MCP server (windoze95/servicewow-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.