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

Annotations already declare this a read-only, idempotent, non-destructive, closed-world lookup, so the safety profile is covered. The description still adds real behavioral context: results are ordered strongest-first, each entry carries days-to-peak and peak rate, and the data comes from the IMO major-shower calendar — useful for trusting and parsing the output.

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 dense sentence that front-loads the resource and the returned content, with no filler. Every clause (ordering, peak distance, peak rate, source) carries information.

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 compensates well by enumerating the fields a caller will receive. The one remaining gap is the default behavior when the optional date is omitted (presumably 'now'), which an agent must infer.

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?

There is one optional parameter with 100% schema description coverage, so the schema already documents the ISO date/date-time format. The description only implicitly ties this parameter to 'on a date' and does not state what happens when it is omitted, so it adds little 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?

States a specific resource (meteor showers) with the exact scope of the answer: showers active on a date plus the next peak on or after it. It even previews the return shape (strongest first, days to peak, peak rate) and names the data source (IMO calendar), leaving no ambiguity about what the tool answers.

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 never says when to reach for this tool or what to do instead; the only guidance ('Leave it out for now') lives in the schema, not the description. It is a single-purpose lookup, so context is implied, but no explicit when/when-not or alternative is offered.

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