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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=true), so the description's job is supplementary — and it does add real context: live 'right now' data, the authoritative NWS source, the fields each alert carries, and a 5-credit cost that an agent should weigh before calling. It does not address the no-alerts-in-effect case or response size.

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?

One dense sentence plus a parenthetical cost tag, front-loaded with the tool's identity and scope. Every clause carries information, though the single long sentence packs payload details that the output schema already supplies.

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 zero-required-parameter read tool with an output schema and full annotation coverage, the definition covers source, currency of data, scope, payload, and cost. The only meaningful omission is what happens when no alerts are active.

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 explains lat/lon pairing and the state fallback, making 3 the baseline. The description only echoes the location flexibility ('any point or state') without adding format or precedence detail beyond 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?

The description names a specific verb and resource ('returns the severe weather warnings, watches and advisories in effect right now') and scopes it to the US via the National Weather Service. It is distinguishable from the generic Weather sibling by the alert-specific payload, though it never names Weather or MarineWeather explicitly to draw the boundary.

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 states the scope ('any point or state in the United States'), which implies the lat/lon vs. state selection, and the schema clarifies the fallback rule. However, there is no explicit when-to-use-this-vs-alternatives guidance, e.g. that forecast conditions belong to Weather and marine alerts to MarineWeather.

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