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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description still adds real behavior: the ten-day horizon, local-time interpretation of planned departures, clarification on missing/ambiguous places, and the returned payload (text, structured data, card, credits, link).

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?

Four tight sentences, front-loaded with the core capability and then the differentiating sibling comparison. No filler, though the credits/link detail is secondary and could be trimmed for a shorter front-load.

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 carries the return-value burden and does so: text plus structured data plus an interactive card, along with credits and a deep link. Error behavior (clarification requests) is also stated, making the definition complete for correct invocation.

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 parameters are already fully documented and the baseline is 3. The description restates the 'departure now' default and the ten-day window already present in the schema, adding no new syntax, format, or edge-case detail beyond it.

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?

Opens with a specific verb+resource+scope: 'Arrival-time weather between named places, defaulting to departure now.' It explicitly names the sibling get_drive_weather and states the distinguishing feature (interactive card vs. no card), so an agent can route between the two without opening either 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?

It clearly frames when to prefer this variant ('with an interactive forecast card') versus the paired tool ('for background checks'). It does not spell out when to prefer this over the highway weather siblings, so the guidance is clear but not exhaustive.

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