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

Annotations already indicate readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds minimal extra behavioral context beyond stating the purposeaaa; it doesn't disclose error behavior, return format specifics, or any side effects. With annotations present, the description provides a modest addition by naming the output fields (videoId/pageType), so 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?

The description is a single concise sentence that fully conveys the tool's function without redundancy. It is front-loaded and free of unnecessary details.

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 simple one-parameter tool, the description is sufficient for the core purpose but lacks details on expected output structure, edge cases (e.g., invalid URLs), or how to interpret pageType values. Since there is no output schema and no additional context, the description is minimally complete but not rich.

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 has 100% coverage (url param with type string), and the description adds crucial semantics by specifying it accepts 'YouTube URL or share link', which clarifies the expected format beyond the schema's generic 'url' field. This compensates for the 0% schema description coverage.

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 resolves a YouTube URL or share link into videoId and pageType. The verb 'resolve' and resource 'YouTube URL' are specifichol and distinguish this tool from siblings like youtube_search or youtube_download, which perform different actions.

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 implies usage (when you need to extract an ID from a URL), but it does not explicitly state when to use this tool versus alternatives, nor does it mention any prerequisites or typical scenarios. It's a single purpose tool, so usage is somewhat obvious, but lacks explicit guidance or exclusions.

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