youtube_reply_to_comment

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

No annotations are provided, so the description must carry the full burden of behavioral disclosure. It only says 'Reply to an existing comment' without mentioning authorization requirements, side effects, validation, or error conditions. As a write operation, this is a significant transparency gap.

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 sentence plus a short Args list, with no redundant details. It is front-loaded and immediately understandable, earning its place without any waste.

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 two-parameter tool, the description covers the essential aspects: the action, the required parameters, and the source for parent_id. It does not mention authentication or error behavior, but the tool is straightforward enough that the provided information is nearly sufficient.

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 coverage is 0%, so the description's Args section is the primary explanation. It adds useful provenance for parent_id ('from youtube_list_comments'), but the text parameter is only described as 'Reply text,' which adds minimal semantic value beyond the schema itself.

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 exactly what the tool does: 'Reply to an existing comment.' It uses a specific verb and resource, and the phrase 'existing comment' distinguishes it from posting a new comment (as youtube_post_comment likely does). The parent_id parameter further reinforces the reply semantics.

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?

It provides clear context by instructing that parent_id should come from youtube_list_comments, which tells the agent where to obtain a valid comment ID. However, it does not explicitly mention when not to use this tool or compare it with youtube_post_comment, so it stops short of full exclusion guidance.

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