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

Annotations already establish readOnly/idempotent/non-destructive, and the description adds substantial extra context: what time horizons are returned (now, 3, 6, 12, 24 hour), that official road-condition service links are included, that road closures are out of scope, and that output is text plus structured data with no card. This is rich behavioral disclosure beyond the safety hints.

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 purpose followed by scope, limitations, and the sibling comparison. Slightly dense, but every sentence carries distinct information and none is padding.

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, and the description compensates by describing the return shape (text and structured data, no card) and the reading windows included. Combined with the annotations and complete schema, an agent has everything needed to call this 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 the schema already documents highway and region, and the description largely restates the region scoping ('optionally scoped to a state, province or town') rather than adding new format or syntax guidance. Baseline 3 is appropriate when the schema carries the parameter burden.

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') plus the scope modifier. It explicitly names the sibling get_highway_weather_interactive and how the two differ (card vs no card), so an agent can route correctly 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?

Gives positive selection criteria ('suitable for scheduled or background checks and summaries'), an exclusion ('does not report road closures'), and names the alternative tool with the condition that selects it (interactive card). Nothing is left to inference.

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