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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), and the description adds real context on top: metrics are derived from the YouTube Data API and the call costs $0.005. It also discloses the shape of the result, including the median-normalized multiple and a too_recent flag that warns some items may be immature. It does not state rate limits or failure modes for private/missing channels.

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 definition is dense and front-loaded: the ranking formula and return shape come first, then cost, then the use case. The parenthetical field list is compact and earns its place by substituting for an output schema, though the opening sentence is long and requires careful parsing.

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 does the work of enumerating returned fields (id, url, title, views, multiple_of_median, views_per_day, age_days, too_recent) and the channel/long/shorts nesting, which is substantial. Gaps remain around the meaning of too_recent, defaults for limit and format, and behavior on channels with no recent uploads.

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 only 33%, with just the channel parameter documented as accepting @handle, UC id, or URL. The description partly compensates by explaining the long/shorts split, which maps to the format enum, but it never clarifies the limit parameter's effect (top-N by multiple?) or default behavior. Baseline 3 is appropriate given partial compensation.

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 resource and computation: a channel's recent uploads ranked by views divided by the channel median, with long-form and Shorts handled separately. It also states the end goal (spotting outlier videos to inform content decisions). It does not explicitly distinguish itself from the sibling youtube_channel_growth, leaving that separation implicit.

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?

There is an explicit when-to-use clause: find videos that did many times a channel's normal views to decide what content to make. It gives clear context but no when-not conditions and never names an alternative or contrast with youtube_channel_growth, so it falls short of full routing guidance.

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