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

Annotations already cover the read-only, non-destructive, open-world profile, yet the description adds genuinely new operational facts: a hard 100-comment ceiling per call, the deliberate omission of commenter names and handles, per-call stablecoin billing, and a refund guarantee for paid-but-undelivered comments. That is exactly the behavioral context annotations cannot express.

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?

Two tightly packed sentences with no filler. Capability and return shape come first, then the operational caveats (data omission, pricing, refunds), which is the right front-loading for an agent scanning for a match.

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?

With no output schema, the description carries the return-value burden and does so (field list plus the explicit note that author identities are absent), and it covers cost and refunds. It stops short of describing failure modes for an invalid or non-video URL, which is the one remaining gap for a paid open-world fetch.

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% and the schema already documents url, sort (with enum) and limit (with defaults, bounds, and clamping behavior). The description only echoes the 100-comment cap, adding no meaning beyond what the schema provides, so the 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?

States a specific verb (get) and resource (comments under a YouTube video) and enumerates the return fields: text, time, likes, reply count. This cleanly separates it from the sibling youtube-transcript and from review-comment tools for other platforms, so an agent can route correctly without opening the schema.

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?

Usage is implied by the input shape ('send the URL of a video'), and the per-call cap of 100 comments hints at scope, but there is no explicit statement of when to use this over youtube-transcript or when-not to use it at all. Adequate but leaves routing to inference.

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