Find indexes that are rarely or never used.
AI agents call PostgreSQL_get_unused_indexes to retrieve information from Postgres without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and analyzes index usage statistics from the database, producing read-only diagnostic information. It has no side effects, does not execute queries, modify data, or perform destructive operations. The blast radius of misuse is minimal—an agent could only obtain information about index performance characteristics.
From the tool's definition Tool name contains 'get' and description states 'Find indexes' — both indicate data retrieval. The tool queries PostgreSQL metadata to identify unused indexes without modifying or executing any database operations.
Documented attack patterns abuse exactly the kind of access PostgreSQL_get_unused_indexes gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Postgres, and nothing reaches the server without passing your rules. This is the rule we recommend for PostgreSQL_get_unused_indexes:
{
"version": "1",
"default": "deny",
"tools": {
"PostgreSQL_get_unused_indexes": {}
}
}PostgreSQL_get_unused_indexes is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Find indexes that are rarely or never used. 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_get_unused_indexes: 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_get_unused_indexes 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_get_unused_indexes 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_get_unused_indexes. 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_get_unused_indexes 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.
Start from Postgres, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
239 Postgres tools catalogued and risk-classified — across an index of 43,000+ MCP servers.