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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds genuine behavioral context beyond that: it returns a recommended bid with a low/high range per keyword, and it discloses that SB only yields campaign-level CPC rather than per-keyword bids. It stops short of noting pagination/limits, but the value-add is real.

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 purpose, then input requirements, then the return shape, then the SB alternative. Every sentence earns its place and there is no redundancy.

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, the description needn't enumerate return fields, and it still summarizes them. Parameter context, the mutual-requirement constraint, and the sibling routing are all covered, so an agent has everything needed to invoke it correctly.

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 the schema already documents asins, campaign_id/ad_group_id and the rest. The description restates the ASIN-vs-campaign/adgroup either/or constraint but adds no syntax, format, or default semantics beyond what the schema provides. Baseline 3 is appropriate when the schema does the heavy lifting.

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 (Get) plus resource (Amazon's suggested Sponsored Products keyword bids) and scope (Sponsored Products keyword bids). It explicitly distinguishes itself from the Sponsored Brands path via get_sponsored_ads_targeting_options, so an agent can route correctly without opening schemas.

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?

Explicitly states the two valid input contexts (ASINs for a new ad group, or campaign_id + ad_group_id for an existing one) and names the alternative tool plus its parameters for the Sponsored Brands case. The when-to-use and when-to-use-something-else conditions are both present.

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