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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds useful behavioral context by noting the data source (NWS) and that alerts are 'active' rather than historical. It does not disclose output shape, pagination, rate limits, or the implications of optional parameters, but the annotations carry much of the burden.

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 description is short and front-loaded with the core purpose, followed by source and pricing/endpoint details. The word 'Active' is repeated from the title, which is minor redundancy, but the overall size is appropriate and every other part adds useful context.

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 a simple read-only tool with rich annotations, the description is mostly adequate. However, it does not clarify that lat/lon and q are alternative inputs, nor does it warn that all parameters are optional and at least one is presumably needed for a meaningful call. With no output schema, some indication of what the response contains would strengthen completeness.

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?

The input schema has 100% description coverage, so parameters are already documented. The description reinforces that lat/lon represent a US coordinate but does not explain the relationship between q and lat/lon or that none are required. Since schema coverage is complete, the baseline 3 is appropriate.

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 clearly identifies the resource as 'Active NWS watches/warnings for a US coordinate', which is specific enough to distinguish from sibling tools like v1_weather or v1_air_quality. The 'US coordinate' scope adds precision, and the endpoint path reinforces the retrieval purpose.

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?

The description gives clear context: this tool returns active NWS watches/warnings for a US location. It does not explicitly name alternative tools or state when not to use them, but the alert-specific wording makes the appropriate use case obvious. It lacks explicit exclusion guidance, which keeps it from a 5.

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