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

The description makes clear this is a read-oriented search operation that returns a results page, but no annotations are present and it does not explicitly mention authentication, rate limits, error behavior, or confirm there are no side effects. The read-only nature is implied rather than fully 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 dense but every clause earns its place: the first sentence front-loads the purpose and output structure, and the second sentence explains real-world use cases and relationships to sibling tools. There is no redundant filler or repeated schema content.

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?

Given there is no output schema, the description thoroughly covers the response shape (videoResults, channelResults, shortsResults, shelves, adsResults, sponsoredResults, positionOnPage) and gives downstream usage context. Pagination is also covered indirectly through the paginationToken parameter, making the tool self-contained enough for an agent.

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?

The input schema already provides 100% descriptive coverage of all 11 parameters, including enums and the sp override behavior. The description itself adds no parameter-level meaning beyond that, so it sits at the baseline for a fully documented 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 opens with 'Searches YouTube for a query' and precisely identifies the resource and action, and it enumerates the distinct result sections returned. This makes the tool's purpose unmistakable and distinguishes it from the channel, video, and transcript sibling tools.

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 lists concrete use cases (competitor monitoring, brand tracking, ad-placement intelligence, creator discovery, trend research) and tells agents to feed returned videoId/channelId into the Video, Channel, or Transcript endpoints. This provides clear guidance on when to use the search tool versus its siblings.

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