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 description adds meaningful behavioral context beyond annotations: it reveals hybrid retrieval, exact-match operators, exclusion syntax, and cross-lingual behavior. It does not describe result structure or pagination, but the added context is substantial.

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 compact: three sentences, each earning its place. The first states the resource, the second the retrieval mechanics, and the third adds query-language capabilities. No redundant or filler content is present.

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 nine parameters, no output schema, and many sibling search tools, the description is adequate but not complete. It covers the core behavior well but omits guidance on when to prefer this over search_batch or search_products, and does not address return-value expectations. The schema compensates for parameter details, but the selection context is incomplete.

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 all parameters thoroughly. The description adds general search-behavior information but does not meaningfully enhance understanding of individual parameters beyond what the schema provides. A baseline of 3 is appropriate.

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 clearly identifies a specific verb and resource: 'Search the Webdex index of crawled websites.' It also explains the combined retrieval approach (BM25 + semantic), making the core purpose concrete. However, it does not differentiate this tool from closely related siblings like search_batch or search_products, so it falls short of a 5.

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?

The description gives useful operational details like quoted phrases, term exclusion, and cross-language search, but it does not state when to use this tool versus alternatives such as search_batch or search_products. There is no explicit when-to-use, when-not-to-use, or alternative routing guidance.

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