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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so safety is covered. The description adds genuinely new behavioral context: the four possible result states, the special not_connected branch and the required agent response, and a caveat that eligibility should be re-verified live. It does not mention rate limits, latency, or whether results can go stale.

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?

Three short sentences, front-loaded with the core purpose and outcome values before the procedural branches. The final line naming 'get_retailer_product / check_listing_eligibility' is slightly muddled since one of those is this same tool, costing a point on structure.

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 compensates by naming the four result states and the not_connected failure mode, which is the critical thing an agent needs to branch on. Coverage is solid for a two-parameter read tool; only rate-limiting and batch-size behavior are left unstated.

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%, including the 1-200 bound on asins and the default for conditionType, so the schema carries parameter semantics. The description only says to pass the ASINs and never explains conditionType's effect on the ELIGIBLE/GATED outcome, adding little beyond the structured field.

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 (check), resource (listing eligibility), and scope (YOUR connected Amazon seller account), and enumerates the exact outcome vocabulary (ELIGIBLE / GATED / RESTRICTED / UNKNOWN). An agent can distinguish this from price-history or product-lookup siblings 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 clear operating instructions: pass the ASINs to verify, and if the result is not_connected, stop and tell the user to connect their account. It also points at get_retailer_product for live verification before buying. It stops short of stating explicit when-not conditions or which sibling to prefer for large batches.

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