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

Annotations already establish readOnlyHint=true, destructiveHint=false, and openWorldHint=true. The description adds value by disclosing the default ad-type set and the shape of the result (overall status plus warnings/ineligibility reasons per ASIN/SKU), which goes beyond the safety profile covered by 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?

Three sentences, front-loaded with the core purpose and then the default behavior and return shape. It is efficient with essentially no wasted words, though it could be marginally tighter.

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 a 100%-covered schema, an output schema, and annotations carrying the safety profile, the description supplies enough context to invoke the tool correctly. Only the absence of explicit sibling routing keeps it short of fully 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 five parameters (including the carefully documented profile_id) are already explained in the schema. The description restates the ad-type default but adds no new format or constraint detail, so the baseline of 3 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?

The description states a specific verb ("Check") and resource ("product eligibility for selected ad types"), making the tool's function immediately clear. It is distinguishable from the nearby sibling get_fba_eligibility by scoping to advertising eligibility, though it never explicitly names or contrasts a sibling.

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?

It explains the default behavior (SP, SB, SD, optionally DSP), which implies when the tool applies, but gives no explicit when-to-use vs when-not guidance or alternative tools (e.g., for FBA eligibility or listing restrictions). Usage is implied rather than spelled out.

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