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

Annotations already declare readOnly/destructive/openWorld, but the description adds meaningful behavior the annotations cannot: it is an async SP-API report whose first call may take 30-60s, it excludes buyer PII, and ship_from_country is best-effort while fulfillment_center_id is authoritative. That is exactly the kind of operational caveat an agent needs.

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?

Dense but well front-loaded: the operation, its data content, the use case, the caveat, and the latency all appear in a logical order with little waste. The leading 'READ-ONLY' is slightly redundant with readOnlyHint=true, which keeps it from a 5.

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 no output schema, the description still conveys the return shape (per-order fulfillment center and derived country), the reliability caveat, the async latency, and the PII exclusion. For a read-only report tool with fully documented parameters, nothing essential is missing.

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 100%, so all five parameters are already documented in the schema; the description adds no filter syntax or format detail beyond it. The note about fulfillment_center_id being authoritative concerns output semantics rather than parameters, so the 3 baseline applies.

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: it returns FBA orders as physically fulfilled by Amazon, with the fulfillment-center-id each item shipped from and the derived ship-from country. It explicitly identifies itself as the 'Amazon Fulfilled Shipments, GENERAL variant' report, which distinguishes it from siblings like get_orders and get_order_items.

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 a clear when-to-use trigger — the user needs to know from which country an FBA order departed — plus a concrete typical case (VAT regime on manually issued invoices for amazon.ae/amazon.sa). It does not name explicit alternatives or when-not-to-use conditions, so it falls short of a 5.

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