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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely useful context beyond that: the hard 7-day window cap, the fact that it returns every day's score/confidence/caveats plus a spot card for the winner, and the 'free during early access' cost signal.

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 core question is front-loaded in the first clause, followed by a returns sentence and a one-line pricing note. Every sentence carries information; there is no filler or restatement 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?

For an 8-parameter tool with an output schema, the description covers scope, destination forms, window limits and result shape well. The remaining gap is behavioural edge cases — what happens when no destination form is supplied or when spot/region conflict with lat/lon — but the output schema carries the return contract.

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 100%, so the baseline is 3. The description adds meaning the schema does not enforce: it frames spot, region, and lat+lon+radius as three alternative ways to specify the destination, which is not expressed via oneOf/anyOf in the schema. It does not, however, clarify defaults or fallback behaviour for the date fields.

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 states a specific verb and resource: it answers 'which day in a window is best for an activity at a destination', and adds the differentiating detail of comparing the winner against a runner-up. It is clearly distinct from siblings like get_conditions (raw conditions) and recommend_spot (place recommendation), and it even names the destination forms it accepts.

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: the agent can infer this is the tool for picking a day within a short window, and the 'max 7 days' and 'Free during early access' notes hint at scope and cost. However, it never says when to prefer this over get_conditions or recommend_spot, nor does it state prerequisites such as needing a resolvable spot/region.

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