pg-insight-mcp

List tables

list_tables

Read-onlyIdempotent

Retrieve tables and views in a PostgreSQL schema with estimated row counts and sizes to assess database structure and data volume.

Instructions

List tables and views in a schema with estimated row counts and sizes.

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_tables"
  }
}

Input Schema

Name	Required	Description	Default
`schema`	No		public

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Nov 5, 2026

TDQS

A3.6/5.0

Behavior3/5

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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so the safety profile is covered. The description adds one genuinely useful behavioral qualifier — counts are estimated, not exact — but says nothing about large schemas, pagination, or visibility/permission behavior for tables the caller cannot access.

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 front-loaded sentence with no filler; the scope and the returned metadata land immediately.

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?

With an output schema present, the description needn't enumerate return fields, and the safety profile comes from annotations. What remains missing is minor: guidance on schema identifier format/default and how this fits against describe_table and list_schemas.

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?

Schema description coverage is 0% for the single 'schema' parameter, so the description has to compensate and only partially does: 'in a schema' confirms the parameter's meaning but not the 'public' default or the expected identifier format (fully qualified vs bare name).

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?

States a clear verb (list) and resource (tables and views) scoped to a schema, plus what the listing includes (estimated row counts and sizes). It is distinguishable from list_schemas and describe_table by resource, though the description never names those siblings explicitly.

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?

Usage is only implied: an agent can infer this is the discovery step before describe_table or sample_rows, and that the scope is one schema. There is no explicit when-to-use or when-not-to-use statement, and no mention of what to do if the schema is unknown (list_schemas).

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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