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

Annotations already mark readOnlyHint as false and destructiveHint as false, so the mutation intent is expected. The description adds useful behavior: it costs 50 quota units, posts as the connected channel, and is explicitly top-level. This is valuable operational context beyond the annotations, although it does not describe failure modes or raw edge behavior.

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 compact and well-structured: core purpose, usefulness of a sibling, quota cost, and bulk behavior. Each sentence adds new information without redundancy, and the most important information appears first.

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 write-oriented tool with 4 parameters, 0% schema coverage, and no output schema, the description gives enough to use the simplest case but not enough to confidently use optional parameters or batch mode correctly. The account role and the relationship between video_id and video_ids are important gaps.

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 0%, so the description should compensate by explaining the parameters. It only adds meaning to video_ids via 'Bulk support', but does not explain what video_id represents more fully, how video_id and video_ids interact, what text means beyond a comment, or how account is resolved.

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 uses a specific verb ('Publica') and a specific resource ('comentário NOVO de topo em um vídeo'), so an agent can clearly understand the core action. It also immediately distinguishes itself from youtube_comment_reply, which is the closely related sibling tool.

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 explicitly states when to use this tool: for a new top-level comment on a video. It also states the alternative: for replying to a person, use youtube_comment_reply. Additionally, it mentions batch mode via video_ids, guiding usage beyond the defaults.

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