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

Annotations already indicate readOnly, destructive, idempotent, and open world hints. The description adds behavioral context: update frequency and that it can return current conditions for multiple airports, which is beyond what annotations provide. No contradictions.

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 two sentences long, front-loading the purpose and key elements. Every word adds value with no filler or repetition.

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?

Given the tool's simplicity, well-documented parameters, and presence of an output schema, the description covers purpose, update frequency, and parameter hints sufficiently. No gaps for the agent to use it correctly.

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?

The input schema has 100% description coverage with clear examples for icao_codes and hours. The description mentions 'one or more airports' but adds no new semantics beyond what the schema already provides, so baseline score of 3 is appropriate.

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 the tool returns current METAR weather observations for one or more airports, listing included elements (wind, visibility, sky condition, etc.). It is specific about what it does but does not explicitly differentiate from sibling tools like aviation.taf.forecast.

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 provides update frequency (every 1 hour, more often in rapid changes) which helps agents decide if data is fresh enough, but it does not give explicit when-to-use or when-not-to-use guidance compared to other aviation tools.

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