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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds genuinely useful behavior: the ordering guarantee (highest revenue first), result caps (10 default, 50 max), and the availability precondition that the workspace must have a connected store. It stops short of stating anything about result emptiness or how 'earned' is computed, so it is not fully closed.

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?

Front-loaded with the resource and ordering, then a short routing sentence, then a one-line precondition — no wasted framing. Minor redundancy in restating the returned field list when an output schema already exists, but the sizing is appropriate for a 5-param tool.

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 handling return values and 80% schema coverage on inputs, the description supplies exactly the missing pieces: ordering, caps, sibling routing, and the store-connection prerequisite. Nothing an agent needs to call it correctly is absent.

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 80%, and the description adds meaning where the schema is silent — it documents the `limit` default and ceiling that the schema leaves undescribed, and clarifies that `days` is a revenue ranking window. The from/to interplay is handled by the schema itself rather than added here.

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+resource (top-earning products) with ranking direction ('best first') and the exact fields returned (title, orders, units, revenue). It explicitly names the two nearest siblings — readStoreOverview for totals, readListings for product pages — so an agent can distinguish it without opening a schema.

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?

Gives explicit when-to-use routing ('For the store's totals use readStoreOverview; for product pages that need work, readListings') plus a hard prerequisite: only for a workspace with a store connected, and it points to listWorkspaces to check. Both the alternative and the exclusion condition are stated.

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