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

No annotations are provided, so the description carries the full behavioral burden. It lists what data is returned but does not state that the operation is read-only, mention rate limits or data freshness, or explain the authentication requirement beyond the bare "PRO" label and the schema's access_token description.

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?

A single tight sentence with no wasted words, and the returned components are front-loaded. The leading "PRO." is terse and not fully self-explanatory but does signal subscription access.

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?

Because there is no output schema, the list of returned elements (7-day, hourly, normals, warnings, sunrise/sunset) is useful. However, it omits sibling differentiation and postal-code format expectations, which are important given the two competing forecast tools.

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 50%, so the description should compensate for the undocumented `postal_code` parameter. It says the forecast is "for a postal code," which identifies the input but does not clarify the expected format or country context; `access_token` is already documented in the schema.

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 resource (forecast) and enumerates its components (7-day, hourly, normals, warnings, sunrise/sunset) scoped to a postal code. The word "Full" hints that it is broader than the sibling `forecast`, but it never explicitly contrasts the two.

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 no guidance on when to use this tool instead of `forecast` or `sites_forecast`. "PRO" implies a subscriber-only feature but does not explain the selection conditions or prerequisites beyond what the schema shows.

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