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

No annotations are provided, so the description carries the burden. It states it returns a view count and that it costs 1 credit per call, which is useful. However, it does not disclose any behavior beyond that, such as whether it might return null for private videos, or any rate limits. It's a simple read operation, so transparency is acceptable but not rich.

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?

Extremely concise: one sentence with key info, plus structured fields like Group and Billing. Front-loaded with the core value. No fluff.

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 one parameter and no output schema, the description is mostly complete. It lacks details like whether the view count is for the current day or total, but the tool name says 'viewCount' and the description says 'number of times viewed', which is enough. With no complexity, this is fine, but it could mention if the video must be public or that it fails for missing IDs.

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 schema description coverage is 100% (the 'description' field covers the parameter), and the example is provided. The description adds the 'id' parameter meaning via schema, but it does not add extra beyond that. Baseline is 3 due to high coverage, but the example and clear format in the schema give a slight boost. However, the description does not reference the parameter directly, so 4 is slightly generous; still, the info is complete.

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 provides the number of times a video has been viewed, and the title aligns with the resource (video view count). However, it does not explicitly distinguish itself from sibling tools beyond being a specific field of video info, but that is clear from the tool name and group.

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: to get view count for a video. It mentions 'Group: Specific video Info' which contextualizes it among siblings, but it does not provide explicit when-to-use vs alternatives, nor any exclusions. It's adequate but minimal.

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