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

Annotations already establish read-only/idempotent safety, and the description adds substantive behavior beyond that: newest-first ordering, pagination termination semantics, counts behavior across song_id/artist_id/q and by video type, output fields per video, and the meaning of queue states (plan_limit vs render_capacity) for waiting videos. This is unusually rich disclosure for a list tool.

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?

It is front-loaded with ordering and pagination, and every sentence carries operational value (pagination, counts, outputs, get_video routing, queue states). It is somewhat dense and the clause 'counts says how many videos match song_id, artist_id and q: all, and by type' is grammatically compressed enough to require re-reading.

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?

There is no output schema, so the description must describe returned shape, which it does: counts, per-video outputs (aspect_ratio, poster_url, poster_seconds, web_url), and queue metadata for waiting videos. It also names the follow-up tool (get_video) for downloads, leaving no major gap for correct invocation.

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?

With 67% schema coverage, the description compensates well by adding the default limit of 50, the fact that cursor must be reused with identical filters, and how counts relate to song_id, artist_id, and q. The q search scope and type enum values are left primarily to the schema, which is acceptable at this coverage level.

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 opens with a specific verb and resource ('Videos, newest first, with status and thumbnails'), establishing both scope and ordering immediately. It explicitly separates this tool from get_video by noting that get_video carries download links, so an agent can distinguish the two without opening schemas.

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 precise pagination protocol: limit defaults to 50, next_cursor is null on the last page, otherwise pass it as cursor with the same filters. It also routes the agent to get_video for download links. However, it never states when to prefer this listing over related tools such as show_video or when not to use it, so usage is well-contextualized but not fully exclusive.

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