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

The read-only/idempotent annotations already cover safety, and the description adds real operational behavior beyond them: it names the upstream source, states that no auth is required, exposes the 15-requests/hour shared throttle, and notes 30-minute caching. This lets an agent anticipate rate-limit and staleness issues. No contradiction with annotations.

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?

Two sentences, front-loaded with the action, followed by returned fields, then operational constraints. The data-source/throttling/cache sentence is dense but every clause earns its place for an agent deciding whether to call and how often.

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 an output schema present and read-only/idempotent annotations, the description covers the remaining practical concerns: data source, auth, rate limiting, and cache. An agent has what it needs to decide to call, set expectations, and interpret results.

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?

Both params are fully described in the schema, including limit range/default and search examples, so the description bears little parameter burden. It adds only a slight clarification that search spans mission/rocket/agency names, which is marginal beyond the schema's 'name/mission/agency' fields; not enough to lift above the high-coverage baseline.

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?

Opens with a specific verb and scope ('List upcoming global orbital launches') and enumerates the returned fields, so an agent immediately knows what to ask for. The qualifier 'upcoming' and the resource order distinguish it from sibling searches like agencies.search/astronauts.search and from a single-launch detail tool, even though those siblings are not named.

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 'upcoming global orbital launches' scope plus the optional free-text search tells the agent when this tool fits: future launches, filterable by mission/rocket/agency. It does not explicitly route to launches.detail for past/specific launches or state when not to use it, but the context is clear enough to avoid misuse.

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