pg_list_functions

List user-defined functions with optional filtering. Use exclude (array) to filter out extension functions. Default limit=500 may need increasing for busy databases.

SERVERPostgreSQL MCP Server SOURCE@neverinfamous/postgres-mcp

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-neverinfamous-postgres-mcp/pg-list-functions.md

WHAT IT DOES

What pg_list_functions does on PostgreSQL MCP Server

AI agents call pg_list_functions to retrieve information from PostgreSQL MCP Server without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

RISK

Why pg_list_functions is rated Low

This tool queries the database schema to enumerate functions. It performs no write, delete, execute, or financial operations. The optional filtering parameters (exclude array, limit) are for controlling the scope of the read, not for altering data. The mention of 'default limit=500' further confirms this is a listing/querying tool.

From the tool's definition Tool name 'pg_list_functions' and description 'List user-defined functions with optional filtering' indicate a query/retrieval operation. The verb 'list' is a classic Read operation that retrieves metadata without modification.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs pg_list_functions safely

PolicyLayer is an MCP gateway: it sits between your AI agents and PostgreSQL MCP Server, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For pg_list_functions, this is the rule to start with:

pg_list_functions Allowed

pg_list_functions is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "pg_list_functions": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect PostgreSQL MCP Server, apply this rule, and every pg_list_functions call is checked against it from then on.

FAQ

Questions about pg_list_functions

What does the pg_list_functions tool do? +

List user-defined functions with optional filtering. Use exclude (array) to filter out extension functions. Default limit=500 may need increasing for busy databases. It is categorised as a Read tool in the PostgreSQL MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on pg_list_functions? +

Register the PostgreSQL MCP Server MCP server in PolicyLayer and add a rule for pg_list_functions: 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 PostgreSQL MCP Server. Nothing to install.

What risk level is pg_list_functions? +

pg_list_functions is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit pg_list_functions? +

Yes. Add a rate_limit block to the pg_list_functions 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.

How do I block pg_list_functions completely? +

Set action: deny in the PolicyLayer policy for pg_list_functions. 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.

What MCP server provides pg_list_functions? +

pg_list_functions is provided by the PostgreSQL MCP Server MCP server (@neverinfamous/postgres-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

What pg_list_functions does on PostgreSQL MCP Server

Why pg_list_functions is rated Low

The rule that runs pg_list_functions safely

Questions about pg_list_functions

More on PostgreSQL MCP Server, and thousands of servers like it.