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

Annotations already cover read-only and open-world, so the description correctly spends its words elsewhere: page size (~48), ordering (newest first), the fact that duration and publish date are null because YouTube doesn't render them, and the credit cost of extra_fetch scaling with page size. That is genuine behavioral disclosure beyond the annotations.

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?

Mostly efficient and front-loaded, with the surface and ordering stated first and the null-field caveat immediately after. The closing 'Costs 1 credit per item fetched, up to the page size. Costs 1 credit.' is redundant and slightly ambiguous about whether the base call is free or costs 1 credit.

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?

No output schema exists, and the description compensates by explaining what fields will be null and how to fill them, plus pagination and cost. The only gap is the unclear base-credit accounting and no explicit note on when cursor pagination should be followed.

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 75%, and the description adds real meaning beyond it: it explains why extra_fetch exists (to populate nulls individually) and quantifies its cost up to the page size. The cursor parameter's role is implied by the 'about 48 per page' statement, though 'cache_max_age' is left entirely to the schema.

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?

States a specific resource and surface: 'A channel's Shorts grid, newest first', which is clearly a channel-scoped Shorts listing. It is distinguishable from youtube_channelVideos by naming 'Shorts', though it never explicitly contrasts with youtube_trendingShorts.

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 by the scope (channel Shorts), and the extra_fetch note implies a when-to-use condition ('fill fields the list page leaves null'). But there is no explicit guidance on when to prefer this over youtube_channelVideos or youtube_trendingShorts, nor any stated prerequisites.

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