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

Annotations declare readOnlyHint and idempotentHint, which already indicate a safe read operation. The description adds minimal behavioral context beyond labeling it a 'feed'—no mention of pagination, rate limits, or what happens with the token parameter.

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 short sentence, which is concise, but it is under-specified. It reads more like a title than a description, failing to provide enough substance to be genuinely useful.

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?

With no output schema and minimal description, the tool is severely incomplete. It does not explain what data is returned, how to paginate (token is likely used for that), or what geo/lang filters do. The agent would have to guess or test extensively.

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 has 0% description coverage for three parameters (geo, lang, token). The description does not explain any of them, leaving the agent to guess what these parameters control. This is a critical gap for a tool with no parameter documentation.

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 states it's a feed of viral/hyped videos, which identifies the resource but is vague about exact scope. It doesn't differentiate from youtube_trending or youtube_home_feed, making it unclear when this tool should be preferred.

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?

No guidance on when to use this tool versus the numerous sibling tools. There is no mention of alternatives or contextual triggers, leaving the agent without direction.

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