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

Annotations indicate readOnlyHint and openWorldHint, so the safe read-only nature is already established. The description adds valuable behavioral context: it explains the pagination pattern and the meaning of has_more, which are not present in the input schema. No contradiction with annotations exists.

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 two sentences, front-loads the core search capability, and includes pagination guidance efficiently. There is no filler or redundant restating of the title.

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 the presence of a rich input schema, an output schema, and annotations, the description covers what an agent needs to invoke the tool correctly, especially the pagination loop. Nothing critical is missing for a search tool with this structure.

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 documents all four parameters with 100% coverage, so the baseline is 3. The description adds meaning by linking next_page_token to the pagination flow and mentioning that has_more indicates another page, which helps agents understand the parameter interaction beyond the schema's individual field descriptions.

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 states the tool searches YouTube for videos or channels, a specific verb and resource. This distinguishes it from sibling tools like search_channel_videos, which are scoped to specific contexts rather than a general YouTube-wide search.

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 provides clear pagination usage guidance with next_page_token and has_more, but it does not explicitly state when to choose this tool over siblings such as search_channel_videos or latest_channel_videos. The intended usage is implied rather than explicitly contrasted.

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