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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), and the description goes well beyond them: it separates forecast from advice, discloses what it infers (mud, ice, fog) versus what it cannot know (trail surface), and states that an official weather warning overrides everything. It also effectively documents the return shape in the absence of an output schema.

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-loaded with the output contract before the input guidance, and almost every clause carries information. The opening 'Our flagship tool' is marketing filler that does not help selection, and the middle run-on sentence about inference versus unknowables is dense, but overall the length is justified by the tool's complexity.

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?

No output schema exists, so the description carries the burden by enumerating the verdict values and the returned fields. Combined with the input guidance and the explicit warning-override rule, an agent has everything needed to call this correctly and interpret the result.

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 100%, so the baseline is 3, but the description adds genuine semantics on top: naming a whole day makes the tool find and judge the best window inside it, and the relationship between start_time and duration_hours as an alternative to a natural-language phrase. The activity enum is restated from the schema rather than extended, which caps this at 4.

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 transformation of a specific resource: weather turned into a go/no_go verdict for a named outdoor activity, and enumerates the returned fields (reason, temp/feels-like, rain, wind, sunset, what to wear, concerns). An agent can distinguish it from get_forecast or get_weather without opening a schema.

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?

Explicitly routes the WHEN-to-go case to a named sibling: 'To find WHEN to go, use find_best_weather_window.' It also explains the accepted forms of the temporal input (start_time + duration_hours, or a phrase, or a whole day which triggers best-window selection), so the calling conditions are fully specified.

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