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

Annotations already declare readOnlyHint=true and destructiveHint=false; the description adds 'Pure data fetch (no AI analysis)' and a mandatory OUTPUT CONTRACT for the 'Account notice:' prefix, which is important behavior not captured in annotations or schema. No contradiction found, though rate limits and result-error behavior are not disclosed.

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?

The description is front-loaded with purpose, then routes to a sibling, then gives operational guidance and the critical output contract. The 'How to use' sentence is useful but slightly beyond selection/invocation needs; otherwise every sentence earns its place.

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?

For a tool with no output schema and a nested filters object, the description covers the returned fields, the raw-vs-analyzed distinction, and the unusual account-notice behavior. It lacks explicit empty-result/error handling and pagination, but those are not critical for correct invocation here.

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 baseline is 3 and the description doesn't need to compensate. It adds only light semantic context by referencing sort order/filters and the returned fields; it doesn't materially enrich parameter meaning beyond the schema.

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 names a specific action ('keyword search'), resource ('Amazon'), and concrete output ('top N products with price, sales, revenue, reviews, rating'). It also distinguishes itself from analyzeNiche ('Pure data fetch (no AI analysis)'), so an agent can discriminate it from the closest sibling 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?

It explicitly states the best use case ('raw product rows (specific sort order or filters)') and names the alternative tool with the exact differentiating condition ('analyzeNiche additionally returns computed market aggregates'). This is explicit routing, not just implied context.

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