pg-insight-mcp

List schemas

list_schemas

Read-onlyIdempotent

Lists user schemas with table and view counts, enabling quick discovery of PostgreSQL data structures before querying or inspecting execution plans.

Instructions

List user schemas with table and view counts.

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
No arguments

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Nov 5, 2026

TDQS

B3.4/5.0

Behavior3/5

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed-world scope, so the safety profile is fully covered. The description adds only that counts of tables and views are included; it says nothing about whether system schemas are excluded ('user schemas' is the only hint), ordering, or behavior on an empty database.

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 short sentence with the verb and resource front-loaded and no filler. The trailing detail about counts earns its place by signaling the return payload.

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?

An output schema exists, so return values need no explanation. However, for a discovery tool sitting beside list_tables and describe_table, the description could have stated scope (which connection/database) and sequencing; as written it is adequate but leaves the agent to infer placement in the workflow.

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

Parameters4/5

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

The tool takes zero parameters, so the description carries no parameter burden and the baseline of 4 applies. Nothing in the description misdescribes or omits a callable input.

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

Purpose4/5

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

Uses a specific verb and resource ('List user schemas') and adds scope detail that the return includes table and view counts, which distinguishes it from list_tables. It does not explicitly contrast with sibling tools, but the resource word 'schemas' vs 'tables' makes the distinction reasonably clear.

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

Usage Guidelines2/5

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

There is no guidance on when to call this versus list_tables or describe_table, nor any stated ordering such as 'call this first to discover schemas before listing tables'. A reader can infer it is a discovery step, but the description never says so.

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

Deploy Server