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

Beyond the readOnly/idempotent annotations, the description reveals the maximum 5-location limit, the comparison semantics, and the comfort outlook classification (ideal > mild > poor > severe). This adds meaningful behavioral context and aligns with the annotations.

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?

Two concise sentences: the first front-loads the core capability and ranking scale, the second gives relevant use cases. There is no filler or redundant restating of the title.

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 description covers the core behavior and implied ranking output, but it does not clarify whether coords and zip_codes are mutually exclusive, what the return structure looks like, or what happens when no inputs are supplied. Since there is no output schema and no required parameters, these gaps matter.

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 schema already documents coords and zip_codes formats and provides the units enum with default. The description adds no parameter-level meaning, and at 67% schema description coverage, the description does not need to fully compensate but also provides no enhancement.

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?

Description states a specific operation: 'Rank up to 5 locations by comfort outlook' with an explicit ordinal scale. It clearly distinguishes this tool from raw weather retrieval siblings like weather_current or weather_forecast by focusing on comparison and ranking.

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?

Concrete use cases are given: 'trip planning, expansion site comparison, event location selection.' This gives clear context for when to use the tool, but it does not explicitly name alternatives or exclusion conditions, so it falls short of a 5.

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