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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is covered. The description still adds real value by disclosing the 'approved' filter and the returned field set, which matters since there is no output schema. It stops short of failure behavior for unknown identifiers.

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 tight sentences, counter and identifier list front-loaded, no filler or restatement of the title.

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 three-parameter read tool with no output schema, naming the returned fields and the accepted identifier forms covers most of what an agent needs. The remaining gap is edge behavior: not-found handling and the fact that supplying no identifier is invalid.

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 coverage is 67% with the slug parameter undocumented, and the description fills that gap by naming it 'product slug' and clarifying that the url parameter accepts either a Shipstry product URL or the product's own website URL. It does not state that all three identifiers are optional or what happens when none is supplied.

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 verb ('Fetch') and resource ('one approved launch'), and enumerates exactly what comes back (description, tags, awards, maker name). The singular scope cleanly separates it from the plural discovery sibling search_launches.

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 tells the agent how to target a launch (four identifier forms) but never states when to reach for this tool versus search_launches, get_winners, or check_url. Usage is implied by 'one approved launch' rather than stated.

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