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

Beyond the readOnly/openWorld annotations it discloses unusually valuable operational facts: the cost ($0.02 per successful call), the payment mechanism (_meta["x402/payment"], USDC on Base), and the billing edge cases (bad input free, not-found/no-match not charged). It omits rate limits and whether disabled comments return an error or an empty set, which keeps it short of a 5.

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?

It is a single dense paragraph that front-loads purpose, then return shape, use case, and finally pricing/payment. Every sentence carries information, though the packed semicolon-heavy style makes the payment requirement easy to skim past.

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?

There is no output schema, so the description compensates by enumerating the per-comment fields and the shared social schema, plus pagination via next_cursor. For a two-parameter read-only tool, an agent has everything needed to call it and interpret the result.

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?

With 100% schema description coverage, both parameters are already documented, including accepted URL forms. The description adds only that next_cursor maps to the cursor parameter for pagination, a marginal clarification over the schema's own wording — baseline 3 applies.

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?

It states a specific verb and resource — the public comments on one YouTube video, addressed by id or URL — so the agent knows exactly what it retrieves. It does not explicitly contrast with the nearest sibling (youtube_transcript), but the resource difference is self-evident.

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?

"Audience feedback and sentiment research" implies a use context, and the pricing note hints that this is a paid call to spend deliberately. However, there is no explicit when-to-use / when-not guidance and it never names alternatives such as youtube_transcript or reddit_comments for adjacent needs.

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