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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The word 'public' hints that no authentication is required, which is modest added context, but the description offers no detail on result count, ranking, or limits. The output schema covers returns, so a 3 is fair.

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?

Two compact sentences, zero waste, with the core purpose front-loaded before the disambiguation sentence.

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 one-parameter read-only autocomplete tool with an output schema and covering annotations, the description carries enough to call it correctly. The remaining gap is the lack of when-to-use detail for this tool itself, which is minor given its narrow scope.

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% for the single 'keyword' parameter, so the schema already documents it fully. The description adds nothing about format or constraints (e.g., partial words, language) beyond the schema, so baseline 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?

States a specific verb ('Returns typeahead keyword suggestions'), the resource ('Amazon's public suggestion API'), and the scope ('for amazon.com'). It also names amazon_search, so the agent can distinguish this autocomplete tool from product search without opening either 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?

Explicitly routes the agent away from this tool with 'Use amazon_search to search Amazon products,' making the boundary clear. It does not, however, state when this tool itself is the right choice (e.g., keyword/autocomplete discovery), so guidance is positive-by-exclusion rather than fully bilateral.

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