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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds genuinely non-obvious behavior: the result is capped at 12 weeks, filtered to weeks with remaining seats, and that upcoming launches are not public data — a real visibility caveat an agent would not get from the schema.

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 sentence that front-loads the resource and cap, then appends the two qualifying constraints in parentheses. No filler, and every clause carries a constraint the agent needs.

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?

An output schema exists, so return-shape explanation is not required, and the annotations cover the safety profile. The remaining weakness is that 'counts only' is slightly opaque — it's unclear whether seats/prices are returned as aggregates or per-week — a small ambiguity for an otherwise simple listing tool.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The description does usefully clarify that the 'next 12' cap and the seats-left filter are fixed, non-configurable behavior rather than optional inputs.

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 concrete resource (launch weeks) and pins down scope: the next 12, only those with seats left, including prices. It implicitly contrasts with get_launch's single-item retrieval, though it never names the sibling explicitly, keeping it short of a 5.

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?

No explicit when-to-use or when-not-to-use guidance against get_launch or list_winners. The phrase 'counts only' hints that this is an aggregate/overview call rather than a detail call, but the agent must infer that routing decision.

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