postgres-mcp-server

analyze_query_indexes

Analyze up to 10 SQL SELECT queries to receive index recommendations, improving query performance by suggesting optimal database indexes.

Instructions

Recommend indexes for specific SQL queries. Provide up to 10 SELECT queries and get index recommendations.

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": {
      "queries": "<queries>"
    },
    "name": "analyze_query_indexes"
  }
}

Input Schema

Name	Required	Description	Default
`queries`	Yes	SQL SELECT queries to analyze (max 10)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv3.0.3May 30, 2026

TDQS

A3.5/5.0

Behavior2/5

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

No annotations are provided, so the description must fully disclose behavior. It states the tool 'recommends' indexes, suggesting it is read-only, but it does not confirm whether recommendations are only advisory or if any side effects occur. Missing details on required permissions, handling of invalid queries, or response structure.

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?

The description is two sentences with no wasted words. The first sentence states the core purpose, and the second provides a usage instruction. It is front-loaded and concise.

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?

Given one well-documented parameter and no output schema, the description is minimally complete. It explains what input to provide and what to expect (recommendations), but lacks information about output format, limitations, or when not to use. Adequate but not rich.

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?

The single parameter 'queries' is fully described in the input schema as 'SQL SELECT queries to analyze (max 10)'. The description adds 'Provide up to 10 SELECT queries' which repeats the schema, adding no new semantic information. Baseline 3 is appropriate given full schema coverage.

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?

The description clearly states the tool recommends indexes for specific SQL queries, using a specific verb ('Recommend') and resource ('indexes'). It distinguishes from siblings like 'analyze_workload_indexes' (workload-level) and 'explain_query' (execution plan), as it focuses on individual SELECT queries.

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 use when you have specific SELECT queries needing index recommendations, but it does not explicitly state when to use this tool versus alternatives like 'analyze_workload_indexes' or 'explain_query'. No exclusions or prerequisites are mentioned.

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