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

Annotations already provide readOnlyHint=true, so the safe read-only nature is known. The description adds valuable behavioral context beyond that: newest-first ordering, the endpoint, the returned item fields, and the pagination wrapper shape when multiple pages exist. No contradictions exist.

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 with no filler. The core action and resource are front-loaded, and the API endpoint, ordering, return fields, and pagination behavior each earn their place. The description is compact yet information-dense.

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 read-only list operation with no output schema, the description covers the essential return shape and pagination behavior, which is the main thing an agent needs beyond the schema. It could be slightly more explicit about the exact response format when no pagination is needed, but the overall context is sufficiently 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?

Schema description coverage is 100%, so every parameter (page, per_page, created_before) is already documented in the schema. The description adds no additional parameter-level meaning, but it does reinforce the pagination concept by mentioning the { data, pagination } wrapper, which supports but does not extend 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?

The description states a specific verb ('List'), a specific resource ('products/items in the catalog'), and ordering ('newest first'). It also names the exact API endpoint (GET /items), which distinguishes it clearly from sibling tools like get_item, create_item, and list_contacts.

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 clearly implies collection retrieval from the catalog and provides pagination context, so an agent can tell when listing is appropriate. It does not explicitly name alternatives or state when not to use this tool, but the purpose is unambiguous enough that no exclusion is truly necessary.

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