postgres-mcp

list_schemas

List user schemas from a PostgreSQL database, optionally including system schemas, to clarify database structure and guide query planning.

Instructions

List schemas (user schemas only by default)

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_schemas"
  }
}

Input Schema

Name	Required	Description	Default
`db`	No	Database id from list_databases
`include_system`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.3.0Aug 2, 2026

TDQS

A3.7/5.0

Behavior3/5

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

With no annotations, the description carries the burden and does disclose a key behavior: it filters to user schemas by default, implying include_system toggles system schemas. However, it does not mention return format, pagination, permissions, or behavior when db is omitted, leaving some gaps.

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?

A single concise sentence that front-loads the action and key default behavior. Every word earns its place, with no filler or redundancy.

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

Completeness3/5

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

The tool is simple, but the description is incomplete in important contexts: it does not clarify whether db is optional or how the tool behaves without it, nor does it describe output shape or edge cases like no schemas found. The schema helps, but the description alone leaves room for ambiguity.

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 schema has 50% coverage: db has a description, but include_system does not. The tool description partially compensates by explaining the default behavior of include_system via 'user schemas only by default'. It adds moderate value beyond the schema, but not enough to fully offset the missing description for include_system.

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 verb 'List' and the resource 'schemas', and adds a specific scope ('user schemas only by default'). This distinguishes it from siblings like list_databases and list_objects, making the purpose immediately obvious.

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

Usage Guidelines3/5

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

The description implies usage by naming the operation and default behavior, but does not explicitly state when to choose this over list_objects or execute_sql. No exclusions or alternatives are mentioned, but the name and context make the primary use case clear.

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

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