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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive). The description adds material context beyond them: the data source (EPA AQS) and an authentication prerequisite (email + key). It does not describe the shape of the returned code lists, but that is a modest gap.

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?

Three sentences, front-loaded with the core purpose, then the calling-order hint, then the auth requirement. No filler; every sentence carries information.

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?

Covers purpose, ordering, source, and credentials for a 6-param read-only tool with no output schema. The only shortfall is that the format of the returned lists is not sketched, though the schema's list enum largely implies it.

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 coverage is 100%, so the baseline is 3. The description earns a bump by clarifying the parameter semantics the schema doesn't spell out — that list values are code vocabularies and that codes map from human terms like 'ozone' and 'North Carolina'.

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?

States a specific verb (look up) and resource (EPA AQS code lists), and frames its role relative to siblings: it supplies the codes 'the other tools in this pack need.' An agent can distinguish it from aqs_monitors or aqs_sample_data without opening a schema.

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?

'Call this FIRST' gives explicit ordering guidance and a concrete use case ('turn "ozone" into 44201 or "North Carolina" into 37'), which is exactly the when-to-use signal an agent needs before invoking dependent AQS tools.

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