PostgreSQL_list_roles_with_superuser
List database roles, optionally showing only superusers.
This record as markdown: /tools/mukul975-postgres-mcp-server/postgresql-list-roles-with-superuser.md
What PostgreSQL_list_roles_with_superuser does on Postgres
AI agents call PostgreSQL_list_roles_with_superuser to retrieve information from Postgres without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why PostgreSQL_list_roles_with_superuser is rated Low
This tool retrieves role information from PostgreSQL—a read-only operation that queries existing data without side effects. However, severity is elevated to 'medium' rather than 'low' because the data retrieved (superuser role membership) is sensitive security metadata.
From the tool's definition Tool name contains 'list' and description states 'List database roles'; this is a query/retrieval operation with no modification or deletion. The word 'showing' indicates data retrieval.
Attacks that exploit this kind of access
The rule that runs PostgreSQL_list_roles_with_superuser safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Postgres, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For PostgreSQL_list_roles_with_superuser, this is the rule to start with:
PostgreSQL_list_roles_with_superuser is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Postgres, apply this rule, and every PostgreSQL_list_roles_with_superuser call is checked against it from then on.
Questions about PostgreSQL_list_roles_with_superuser
List database roles, optionally showing only superusers. It is categorised as a Read tool in the Postgres MCP Server, which means it retrieves data without modifying state.
Register the Postgres MCP server in PolicyLayer and add a rule for PostgreSQL_list_roles_with_superuser: 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 Postgres. Nothing to install.
PostgreSQL_list_roles_with_superuser 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 PostgreSQL_list_roles_with_superuser 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 PostgreSQL_list_roles_with_superuser. 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.
PostgreSQL_list_roles_with_superuser is provided by the Postgres MCP server (mukul975/postgres-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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