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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description does add genuinely useful behavioral context — credit cost and the warning that repeated requests may purchase data again — but the pricing text is self-inconsistent ("at least 10 Nexscope credits" versus "1 credit per request"), which muddies rather than clarifies the cost model.

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 first two sentences are well-formed and front-loaded, but everything after is pasted marketing boilerplate: a repeated title fragment ("YouTube Community Post Details API View Pricing Get the details of a community post"), a conflicting per-request price, and a disclaimer about supplier units. That trailing block is redundant with itself and does not earn its place.

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 usefully compensates by listing what the response contains, including the conditional linked video. A read-only lookup with one required URL parameter needs little more; only the cost model's inconsistency and absent failure modes keep it from full marks.

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?

There is a single parameter with 100% schema description coverage ("The URL of the YouTube community post to get"), so the schema already carries the semantics. The description adds nothing about accepted URL formats, post-ID vs full-URL forms, or error behavior, leaving the baseline score 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 names a specific verb and resource ("Retrieves the full details of a YouTube community post") and enumerates the returned fields: text content, attached images, like count, publish date, channel info, and linked video. It does not explicitly distinguish itself from the sibling social_youtube_channel_community_posts (which lists a channel's posts), so differentiation is only implied by the word "details".

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 rather than stated: an agent can infer this is the follow-up to a listing call once a post URL is known. There is no explicit when-to-use/when-not-to-use guidance and no named alternative among the many YouTube siblings, leaving the routing decision to inference.

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