EPA Air Quality System (AQS) MCP Server

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

With no annotations provided, the description carries full burden. It discloses authentication behavior (email/API key usage with environment variable fallback) and date constraints (same calendar year requirement), which are useful behavioral traits. However, it doesn't mention rate limits, pagination, error handling, or what 'detailed information' specifically includes beyond the listed fields. It adds some context but leaves gaps for a tool with 7 parameters.

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

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

The description is well-structured with a clear purpose statement followed by parameter details and authentication note. It's appropriately sized for a 7-parameter tool. Some redundancy exists between description and schema (e.g., date format mentioned in both), but overall it's efficient and front-loaded with the core functionality.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with 7 parameters, no annotations, and no output schema, the description provides adequate but incomplete context. It covers authentication, parameter semantics, and basic constraints, but lacks details on return format (beyond 'detailed information'), error cases, or performance characteristics. Given the complexity and lack of structured metadata, it should do more to compensate.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so baseline is 3. The description adds significant value by providing common parameter code examples (e.g., 44201 for Ozone) and clarifying FIPS code formats with specific examples (California='06', Los Angeles='037'). This enhances understanding beyond the schema's generic descriptions. However, it doesn't explain all parameters equally (email/key get less detail).

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states 'Get all air quality monitors in a county' with specific resource (air quality monitors) and geographic scope (county). It distinguishes from siblings like aqs_monitors_by_state or aqs_monitors_by_site by specifying county-level retrieval, though it doesn't explicitly contrast with all monitor-related siblings. The purpose is specific but could be more explicit about sibling differentiation.

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

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

The description implies usage context through parameter explanations (e.g., date constraints, FIPS codes) but doesn't explicitly state when to use this tool versus alternatives like aqs_monitors_by_state or aqs_monitors_by_site. The sibling list shows many similar tools, but no guidance is provided on selecting among them. Usage is implied rather than explicitly guided.

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