EPA Air Quality System (AQS) MCP Server

aqs_list_parameter_classes

Retrieve parameter classification groups from the EPA Air Quality System to identify categories like criteria pollutants, air toxics, or meteorological data for targeted air quality queries.

Instructions

Get a list of parameter classification groups (e.g., "CRITERIA", "AIR TOXICS", "METEOROLOGICAL"). Use the class name to query parameters within that class using aqs_list_parameters. Common classes: CRITERIA (criteria pollutants like ozone, PM2.5), AIR TOXICS (hazardous air pollutants), METEOROLOGICAL (weather data).

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": "aqs_list_parameter_classes"
  }
}

Input Schema

Name	Required	Description	Default
`email`	No	Registered email address for AQS API. Optional if AQS_EMAIL env var is set.
`key`	No	AQS API key. Optional if AQS_API_KEY env var is set.

Schema Changelog

Changes observed during successful MCP inspections.

First observedJan 28, 2026

TDQS

A4/5.0

Behavior3/5

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

No annotations are provided, so the description carries full burden. It describes what the tool returns (classification groups) and their purpose, but doesn't disclose behavioral traits like authentication requirements, rate limits, error handling, or response format. The description is accurate but lacks operational details.

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 efficiently structured in two sentences: first stating the purpose with examples, second explaining usage context with concrete examples. Every sentence adds value without redundancy.

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?

For a simple list tool with 2 optional parameters and no output schema, the description provides good context about what's returned and how to use it. It could be more complete by mentioning authentication requirements or response format, but covers the essential purpose and usage well given the tool's simplicity.

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 schema already documents both parameters (email and key) with their optional nature and environment variable alternatives. The description adds no parameter-specific information beyond what's in the schema, meeting the baseline for high 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 verb 'Get' and resource 'list of parameter classification groups' with specific examples like 'CRITERIA', 'AIR TOXICS', 'METEOROLOGICAL'. It distinguishes from sibling tools by mentioning aqs_list_parameters as a related but different tool for querying within classes.

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?

The description provides clear context by explaining that the output class names should be used with aqs_list_parameters for further queries, and gives examples of common classes. However, it doesn't explicitly state when NOT to use this tool or compare it to all sibling alternatives beyond aqs_list_parameters.

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