find_alternates

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

With no annotations, the description carries the full burden. It discloses a key behavioral trait: the tool does not perform bulk geo-radius search and requires candidateAirportIds. However, it does not describe the return format, how radiusNm interacts with candidate filtering, or the behavior when no candidates meet the weather minima. The mismatch with the schema (candidateAirportIds not marked required) also introduces uncertainty.

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, front-loaded with the primary purpose, and the critical caveat is highlighted with 'IMPORTANT.' Every clause adds value, and there is no redundant content.

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?

The tool has 5 parameters, no output schema, and no annotations, yet the description is very brief. It does not explain the return value, how the candidates are evaluated, what radiusNm does, or the outcome if none meet the minima. The regulatory context helps but does not compensate for the operational details needed to use the tool 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?

Schema description coverage is 0%, so the description must compensate. It explains the meaning of minCeilingFt/minVisibilitySm via 'ceiling/visibility' and makes candidateAirportIds a central concept. However, it omits radiusNm entirely and contradicts the schema by stating candidateAirportIds 'must be supplied' while the schema lists only airportId as required. This creates confusion rather than clarity.

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's function: 'Find alternate airports near a given airport that currently meet minimum ceiling/visibility.' It also distinguishes itself from sibling tools by emphasizing the weather-based alternate selection and the regulatory context (14 CFR 91.103(a)). The explicit caveat about no bulk geo-radius search further sharpens its scope.

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 a clear when-to-use signal: satisfying the 14 CFR 91.103(a) requirement to consider alternates. It also gives an explicit usage instruction: 'you must supply candidateAirportIds,' and warns against expecting discovery. It does not mention alternative tools, but the context is sufficient.

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