Get size information for all databases in the cluster.
AI agents call PostgreSQL_get_database_size 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 metadata about database sizes without modifying any data, executing code, or producing side effects. It is a pure read operation that gathers diagnostic information. The blast radius of misuse is minimal—an attacker could enumerate database sizes but cannot access data, modify databases, or compromise system integrity.
From the tool's definition Tool name 'get_database_size' and description 'Get size information for all databases' indicate a query/retrieval operation with no modification or side effects.
Documented attack patterns abuse exactly the kind of access PostgreSQL_get_database_size 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_database_size:
{
"version": "1",
"default": "deny",
"tools": {
"PostgreSQL_get_database_size": {}
}
}PostgreSQL_get_database_size is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get size information for all databases in the cluster. 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_database_size: 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_database_size 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_database_size 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_database_size. 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_database_size 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.
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239 Postgres tools catalogued and risk-classified — across an index of 43,000+ MCP servers.