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

Annotations already declare readOnly, non-destructive and openWorld, and the description adds real value on top: the verdict is date- and weather-dependent, daylight and animal sightings are factored in, and the payload includes a map, 3D fly-through video and GPX link. It does not discuss caching, failures for unknown ids, or payload size, keeping it short of a 5.

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?

A single front-loaded sentence that opens with the identifying constraint (one route by id) before listing outputs, with no filler. It is dense and clause-heavy, but every clause maps to a real returned field, so nothing is wasted.

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 no output schema, the description must describe the return payload, and it does so thoroughly (metrics, verdict, safety points, map, links). The remaining gap is the undocumented 'kind' parameter and no note on behavior for invalid ids or unavailable weather data.

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 67%, so the schema carries most of the load. The description reinforces id ('by its route id') and adds meaning to date by tying it to the weather/daylight verdict, but the 'kind' enum (hiking/cycling) is never mentioned and its effect on results is unexplained.

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 retrieval verb and resource ('One Wai Trails route by its route id') and then enumerates exactly what comes back: length, ascent/descent, height range, effort, walking time, a go/caution verdict, map and link. That level of specificity clearly separates it from the sibling list-style tool wai_trails.

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?

Usage is implied rather than stated: 'One ... route by its route id' suggests the list tool supplies ids, and 'Answer with the returned numbers, not an estimate made before the call' tells the agent to trust live results over prior knowledge. But it never explicitly says when to prefer this over wai_trails or what to do if the id is unknown.

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