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 new behavioral context: the forecast horizons returned, the inclusion of official road-condition service links, the response shape (text plus structured data with an interactive card), and a negative disclosure about road closures. It stops short of mentioning rate limits or data freshness/auth needs.

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 sentences, front-loaded with the core action, and every sentence carries information (scope, content, exclusion, sibling routing). The clause 'Returns text and structured data with an interactive forecast card' partially restates the title's '(card)' label, which is the only mild redundancy.

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 burden of describing returns, and it does: text plus structured data with an interactive card, the time horizons, and road-condition links. Combined with the routing to the non-card sibling and the road-closure caveat, an agent has everything needed to select and 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?

Schema description coverage is 100%, so all three parameters are already documented, and the baseline is 3. The description corroborates the 'region' semantics by saying the forecast is 'optionally scoped to a state, province or town', but adds no syntax or format detail beyond the schema and never mentions the 'intent' parameter.

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 and resource ('Read the current published forecast for a supported highway'), names the optional scope, and enumerates the delivered content (now/3/6/12/24h readings, road-condition links). It explicitly distinguishes itself from the sibling get_highway_weather, so an agent can separate 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?

Names the alternative tool explicitly and gives the condition that selects it: the paired get_highway_weather returns the same forecast without a card 'for background checks', implying this tool is for card/interactive presentation. It also states a clear exclusion ('This does not report road closures'), so the agent knows what not to rely on it for.

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