Read comments on one of your YouTube videos

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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description reinforces this with 'Read-only, 0 credits' and 'Needs a connected YouTube channel.' It adds useful context like return fields and ordering ('newest first') and the cost implication (0 credits), which goes beyond the annotations. No contradictions found.

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 three concise sentences, each earning its place: purpose, analogy to a sibling, and return/cost/prerequisite details. It is front-loaded with the core action and avoids redundancy, making it efficient for an agent to parse quickly.

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 list tool with 2 params and no output schema, the description covers essential aspects: purpose, return fields and ordering, cost, and prerequisite. It does not mention whether replies are included or error behavior, but given the straightforward nature and the 100% schema coverage, these are minor gaps and the description is sufficiently complete.

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 description coverage is 100%, so the schema already documents both videoId and limit thoroughly. The description does not add any additional parameter-specific semantics beyond what the schema provides, so it meets the baseline but does not elevate it.

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 action ('Read the comments under a video on the connected channel') and the resource (YouTube video). It also distinguishes this tool from its Meta counterpart by explicitly referring to list_meta_comments, making its scope unambiguous among numerous platform-specific siblings.

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 context that this is for gathering 'questions, objections and exact wording real viewers use' for ad copy, and draws an explicit comparison to list_meta_comments, implying when to use this tool versus the Meta equivalent. However, it does not explicitly state exclusions or alternative tools for other platforms, though the mention of 'connected YouTube channel' implies the prerequisite.

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