PgAdmin-MCP

pg_describe_table

Describe columns for a PostgreSQL table or view. Specify schema, database, or profile to inspect table structure across environments.

Instructions

Describe columns for a table or view. Optional schema, database, and/or profile override.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "table": "<table>"
    },
    "name": "pg_describe_table"
  }
}

Input Schema

Name	Required	Description
`table`	Yes	Table or view name
`schema`	No	Schema name (default: public)
`profile`	No	Connection profile: "dev" \| "qa" \| "default". Uses credentials from mcp.json (PG_DEV_* / PG_QA_*). Omit to use the sticky session profile from pg_set_profile / PG_PROFILE.
`database`	No	Optional database name override

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.1Sep 2, 2026

TDQS

A3.5/5.0

Behavior3/5

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

With no annotations, the description carries the full behavioral burden. It discloses that the tool is an introspection operation and that views are supported, but it does not mention output shape, errors, or side-effect profile. Adequate but minimal.

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?

Two short sentences front-load the core action and then summarize the optional overrides. There is no filler, no repetition of the schema, and every part of the description earns its place.

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?

Invocation details are well covered by the schema and description, and the result is implied as column descriptions. However, without an output schema, the return format is unspecified, and there is no guidance on profile defaulting or when to use pg_query instead.

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 100%, so the baseline is 3. The description's mention of table/view and optional overrides aligns with the schema but adds no additional meaning or guidance beyond what the schema already provides.

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 specific action, 'Describe columns', with a clear target, 'a table or view'. This differentiates it from the sibling list/database tools even though no sibling is named explicitly. The scope is unambiguous and not a tautology.

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 mentioning optional schema, database, and profile overrides, but it does not explicitly say when to prefer this tool over pg_query or pg_list_tables. No alternatives, exclusions, or conditions are stated.

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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