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 only adds that results are video metadata; it says nothing about pagination, result limits, or ranking behavior, so with annotations carrying the load a 3 is appropriate.

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 tight sentences, with the tool's scope front-loaded and the alternative-routing note second. No filler.

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?

An output schema exists, so return values need not be explained, and a single-parameter search tool needs little else. The definition covers scope and one alternative; mentioning the general yahoo_search sibling would have made it 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 coverage is 100% for the single required parameter q, so the schema already documents everything needed. The description's 'by query' phrasing adds no format or syntax detail beyond the schema, so the 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 (Search) and resource (Yahoo Videos) plus the return type (video-result metadata), and names a sibling it is not (yahoo_search_news). An agent can distinguish it from the many yahoo_* search variants without opening the 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?

Gives an explicit alternative with the condition that selects it: use yahoo_search_news when the query needs news results. It does not mention the closely related yahoo_search (general web) or yahoo_search_images, so exclusions are incomplete, but the routing guidance present is clear.

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