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

Beyond readOnlyHint/openWorldHint/destructiveHint, the description discloses pagination via continuationToken, that repeated requests may re-purchase data, and the credit cost of a completed lookup — all useful context an agent cannot get from annotations. It is undercut by an internal cost inconsistency ("at least 10 Nexscope credits" versus "1 credit per request" in the pasted pricing block), which could mislead cost budgeting.

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 core paragraph is repeated verbatim twice, and the middle block is pasted marketing/pricing boilerplate ("View Pricing", "Get paginated videos from a YouTube channel..."). The useful constraints are front-loaded, but roughly half the text is redundant, forcing an agent to reconcile duplicated and conflicting cost statements.

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?

For a read-only paginated list tool with no output schema, the description covers return fields, sorting, paging, the extras tradeoff, cost, and the one unsupported capability with a redirect to the right endpoint. Nothing essential to calling it correctly is missing; the only defect is duplication, which is a structure issue rather than a completeness gap.

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%, so baseline is 3, but the description adds real meaning: it establishes that a channel is addressed by either channelId or handle, that sort accepts latest or popular, that extras mean like count, comment count, and description, and that continuationToken drives paging. The includeExtras reliability caveat lives only in the schema, not the description, which keeps this from a 5.

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 first sentence names a specific verb and resource ("Fetches a paginated list of videos uploaded by a YouTube channel") and enumerates the returned fields, so an agent immediately knows what it gets. It is distinguishable from siblings like social_youtube_channel_shorts or social_youtube_channel_lives by the 'uploaded videos' framing, though it never explicitly contrasts itself with those siblings or with social_youtube_video_detail.

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 gives one concrete routing rule: paid-promotion filtering is unsupported here, so use /v1/youtube/video and read isPaidPromotion. That is genuine alternative-naming. However, there is no guidance on when to prefer this over social_youtube_channel_shorts, social_youtube_channel_playlists, or the channel/search siblings, and no statement of prerequisites such as supplying channelId or handle.

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