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

Annotations already establish read-only, idempotent, and non-destructive behavior. The description adds value beyond annotations by stating what the tool returns (canonical Lunoo URL and public structured metadata) and by prohibiting use for fabricating rankings.

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?

Three focused sentences with no filler. Usage context, required input, return value, and a critical constraint are all front-loaded and each sentence earns its place.

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 single-parameter, read-only lookup tool with rich annotations and no output schema, the description is largely complete. It states the return values at a useful level, though enumerating the specific metadata fields would make it fully complete.

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 schema already documents the single 'slug' parameter with a description and example, so schema coverage is 100%. The description reinforces that the slug must be exact and come from a Lunoo result or URL, but mostly restates information already present in 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 verb ('get'), resource ('item details'), and the exact context (after a ranking result, for details about one item). Clearly distinguishes from siblings by tying it to individual item lookup rather than rankings or niche finding.

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?

Explicitly tells the agent when to use the tool: after a ranking result, when the user wants details about one item. It also gives a when-not instruction by warning not to use it to invent rankings not returned by get_rankings, effectively directing ranking needs to a sibling.

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