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

Annotations already establish read-only, open-world, non-destructive behavior, so the description does not need to repeat safety information. It adds useful behavioral context beyond annotations by explaining that results are returned one page at a time, that tab/sort only apply to the first page, and that continuation tokens fetch subsequent pages.

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 description is front-loaded with the primary usage condition, then moves cleanly through return behavior, parameter meaning, and pagination. Every sentence adds information, and there is no redundant restatement of the tool name or schema.

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 paginated list tool with four parameters, enum options, and no output schema, the description covers the essential behavioral details: what is returned, how tab and sort work, their first-page limitation, and how to request the next page with continuation. An agent has enough context to select and invoke it correctly.

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 the schema already documents all four parameters. The description still adds value beyond the schema by clarifying the intended meaning of tab and sort, their defaults, and the important caveat that both apply only to the first page, which is not fully captured in the schema descriptions.

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 states a specific verb and resource: browse a YouTube channel's uploads, including older episodes, popular videos, Shorts, and past live streams. It clearly distinguishes this from the latest-videos path by saying it is for browsing 'beyond its latest videos,' so an agent can tell why this tool exists alongside siblings like get_channel_latest_videos.

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 a clear usage context: use this when the user wants to browse channel uploads beyond the latest videos, with concrete examples of older episodes, popular videos, Shorts, and live streams. It does not explicitly name alternative tools such as search_channel_videos or state when not to use this tool, which keeps it below a full 5.

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