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

The annotations declare readOnlyHint=true, and the description adds meaningful behavioral detail beyond that: it explains member kinds, the `reference: true` flag for Wikipedia ingredient cards, the `app_url_template` substitution rule, and that `unavailable_count` reports unresolved members. This gives the agent a solid understanding of what the result contains without contradicting the 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?

The description is compact yet information-dense. Every clause adds value: the definition of curated shelves, the member structure, the reference flag, the app link template, and the unavailable_count meaning. It is front-loaded with the action and resource, and there is no filler or repetition.

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?

Even though there is no output schema, the description supplies all essential return-value semantics: the top-level fields, the member object shape, the allowed kinds, the reference flag, the link-building instruction, and the meaning of unavailable_count. With zero parameters and a read-only annotation, this is sufficient for an agent to invoke the tool and interpret its result correctly.

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 has zero parameters, so there is nothing for the description to clarify about argument semantics. The schema already covers parameters completely, and the description focuses on output behavior instead, which is appropriate for a parameterless read-only listing tool.

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 states a specific verb ('List') and a specific resource ('the collection's current curated shelves'), and then enumerates exactly what is returned: titles, descriptions, cover photos, and member details. It also distinguishes shelves from other tools by noting they are 'themed groups spanning all entry kinds,' so an agent can clearly identify this as the listing operation.

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 gives clear context: this tool lists current curated shelves and describes their composition. It does not explicitly name sibling alternatives or state when not to use it, but none of the sibling tools perform the same listing function, so the usage context is already clear enough to avoid confusion.

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