postgres-mcp-server

list_servers

Discover all configured PostgreSQL servers and their connection status. Use this first to get available server names before proceeding with other actions.

Instructions

List all configured PostgreSQL servers. Call this FIRST to discover available server names before using list_databases or switch_server_db. Returns server names and connection status.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "list_servers"
  }
}

Input Schema

Name	Required	Description	Default
`filter`	No	Filter servers by name (case-insensitive partial match)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv3.0.3May 30, 2026

TDQS

A4.4/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

While no annotations are provided, the description reveals that the tool returns server names and connection status, implying it checks connectivity. It does not explicitly state it is read-only, but 'List' implies no destructive side effects.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three concise sentences: purpose, usage guidance, output. No extraneous words, front-loaded with the most important information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given no output schema, the description mentions the return values (server names and connection status). It does not cover potential edge cases like empty lists, but it is adequate for this simple tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The description adds no information about the 'filter' parameter beyond what is already in the input schema (which has a comprehensive description). Schema coverage is 100%, so baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: 'List all configured PostgreSQL servers.' It distinguishes from sibling tools like list_databases and switch_server_db by instructing to call this first to discover server names.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit guidance is given: 'Call this FIRST to discover available server names before using list_databases or switch_server_db.' This tells the agent when and in what order to use the tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.