mcp-db-universal

db_query

Execute SELECT SQL queries to retrieve data from your database. Use this tool for all read operations, returning results up to a specified row limit.

Instructions

Execute a SELECT SQL query and return results. Use this for all read operations.

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": {
      "sql": "<sql>"
    },
    "name": "db_query"
  }
}

Input Schema

Name	Required	Description	Default
`sql`	Yes	A SELECT SQL query. Must be a read-only statement.
`limit`	No	Max rows to return (default 100, max 1000)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Sep 6, 2026

TDQS

A3.8/5.0

Behavior3/5

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

With no annotations, the description itself signals safe read-only behavior by restricting to SELECT and read operations. However, it adds little beyond that—no mention of side-effect absence, limit enforcement, timeout, or error behavior—so the burden is only partially met.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two concise sentences front-load the action and scope. No filler, though the space could have been used to mention the write alternative.

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?

Adequate for a simple SELECT tool, but leaves selection nuance to inference: it does not explicitly distinguish db_query from db_execute or specialized read-only metadata tools. The return value is only described generically as 'results.'

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 both parameters are already documented. The description adds no parameter-level detail beyond what the schema provides.

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?

States a specific verb and resource: 'Execute a SELECT SQL query and return results.' It also explicitly classifies the tool as the read-operation entry point, which distinguishes it from write and utility siblings.

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

Usage Guidelines4/5

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

Gives clear invocation context: 'Use this for all read operations.' It does not explicitly name db_execute as the write counterpart or specialized metadata tools as alternatives, so it stops short of full exclusion guidance.

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

Deploy Server