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

Annotations already establish read-only, non-destructive, closed-world behavior, so the bar is lower, and the description still adds real context: rows surface tenant-wide for any marketplace-scoped key and are anchored to the primary marketplace, plus order_marketplace_id is derived and null when no order matches. That is meaningful data-model behavior beyond 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?

Front-loaded with the core capability in the first sentence, then two sentences of genuinely load-bearing marketplace semantics. No filler or repetition of the schema.

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 present, return-value detail is unnecessary, and the description covers scope, filters, and the tricky multi-marketplace attribution behavior. Pagination is left to the schema, which documents it well, so coverage is nearly 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 all 12 parameters are already documented in the schema; the description only restates the filter dimensions (date, ASIN, SKU, reason, disposition) without adding syntax or edge-case semantics. Baseline 3 is appropriate.

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 and resource ('Get FBA return records') and immediately enumerates the dimensions it can be filtered on. This clearly separates it from neighbors like get_reimbursements or get_order_items without needing to name them.

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 filter list implies when the tool is useful, but there is no explicit when-to-use/when-not guidance and no named alternative tool. An agent must infer that this is the returns-analytics path rather than, say, order history.

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