List Comment Replies

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

The description goes beyond annotations by detailing pagination behavior, the exact return structure (including fields like id, authorDisplayName, text, etc.), error conditions (404, 403), and default values. Annotations already indicate read-only, non-destructive, idempotent, and open-world, so the description adds significant context on how the tool behaves.

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 well-structured with clear sections (Args, Returns, Examples, Errors). It is concise, using only necessary information without redundancy. Every sentence serves a purpose.

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?

Despite having no output schema in structured form, the description provides a detailed JSON return schema, pagination details, error handling, and a usage example. This fully compensates for the lack of formal output schema and makes the tool's behavior completely transparent.

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?

All four parameters are fully described in the input schema (100% coverage). The description reiterates the same information with added context like defaults and an example, but does not provide new meaning beyond what the schema already conveys. Baseline of 3 is appropriate.

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 'Retrieves a page of replies to a specific top-level comment thread,' specifying the verb, resource, and scope. It distinguishes from siblings like 'youtube_list_comment_threads' (which lists top-level threads) and 'youtube_reply_to_comment' (which creates replies).

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 clear context for when to use the tool (when you have a parent comment ID and want replies) and includes examples and error cases. However, it does not explicitly state when not to use it or directly contrast with sibling tools, though this is implied by the name and sibling list.

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