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

Annotations already declare read-only/idempotent/closed-world, so the bar is low, yet the description adds rich operational context: the 3-station and 25 km caps, the elevation-band grouping, the named networks, and the key data-availability rule that daily networks carry depth while hourly ones carry temperature and wind.

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?

Front-loads the core payload (what is measured, scope, bands) before the data-availability rule and usage examples. It is dense but every clause carries operational meaning; slightly long, which keeps it from a 5.

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?

With an output schema present, return values need no explanation, and the description covers scope, limits, fields, network behavior, and sibling routing. An agent has everything needed to call 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?

Single parameter with 100% schema description coverage that fully documents the slug format and its source (search_resorts). The description adds no slug detail beyond the schema, so baseline 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?

States a specific verb (what instruments measured) and resource (nearby stations) with precise scope: up to three stations within 25 km, split by elevation band. Explicitly distinguishes itself from get_resort_conditions, so an agent can tell them apart without opening schemas.

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?

Names the exact questions it answers ("what is it like at the top right now", "how old is that number") and routes the alternative use case — the snow report — to get_resort_conditions. This is explicit when-to-use plus alternative routing.

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