Skip to main content
Glama
Sign In
Northwind PostgreSQL MCP Server

Northwind PostgreSQL MCP Server

by mosesliao
OverviewSchemaSourceRelated ServersDiscussionsAdmin
Python
Local

sample_table

Preview sample rows from a specified Northwind table to quickly inspect column values and verify data before writing queries.

Instructions

Return the first N rows of a table (default 5, max 100).

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_name": "<table_name>"
    },
    "name": "sample_table"
  }
}

Input Schema

NameRequiredDescriptionDefault
limitNo
table_nameYes

Output Schema

NameRequiredDescriptionDefault
resultYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv1.0.0

TDQS

B3.3/5.0
Behavior2/5

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

No annotations are supplied, so the description carries the full burden, yet it only mentions the row cap. It never states that this is a read-only operation, what 'first' means without an ORDER BY, whether it errors on an unknown table, or anything about permissions. The default/max detail is useful but far short of the disclosure a zero-annotation tool needs.

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 the constraint in parentheses and zero filler. Nothing to cut.

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 and an output schema exists, so return shape needn't be described. Still missing for correct invocation are the meaning of table_name (valid existing table, discoverable via list_tables) and the row-ordering semantics, which leave a real gap for a preview 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?

Schema coverage is 0%, so the description must compensate for both parameters. It adds a maximum (100) that the schema lacks and restates the default, but table_name is left unexplained — no hint that it must be an existing table name obtainable via list_tables — so the compensation is partial.

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 verb and resource: 'Return the first N rows of a table'. An agent can tell it apart from query (arbitrary SQL) and describe_table (schema only) without opening the schema. It stops short of 5 because it never names those siblings or clarifies the boundary against query.

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: 'sample' combined with 'first N rows' suggests a quick preview, but there is no explicit when-to-use, no when-not, and no routing to alternatives such as query for filtered results or describe_table for column metadata.

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

Deploy Server

Other Tools