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

Annotations already cover readOnly/idempotent/non-destructive, yet the description adds substantive behavior: live fetch rather than cached, a hard 50 cap, platform-dependent ordering (YouTube by relevance), a refund on zero-result calls, a trust warning about third-party text, and a 3-credit cost. These are exactly the traits 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?

Front-loaded with the verb, resource, and cap; each following sentence adds a distinct fact (return fields, ordering caveat, refund, trust, cost). No redundancy with the title.

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 compensates by listing the returned fields and the ordering behavior, and it discloses cost and refund policy. An agent has enough to decide whether to call it and how to interpret results.

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 100% and all three parameters are documented in the schema, so baseline is 3. The description reinforces that the URL may be tracked or untracked and that results are capped at 50, but adds no format or syntax detail beyond the schema.

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 and resource ('Returns up to 50 comments of one public post, fetched live from the platform') and enumerates what each comment contains. It is clearly separable from sibling get_post or download_post_media, which do not return comment threads.

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 names the two input modes (public post URL, tracked or not, or an internal post id) and warns to sort by likes yourself, which is useful operational guidance. However, it never says when to reach for this tool instead of a sibling like get_post or resolve_post_url, so usage is implied rather than routed.

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