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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so safety is covered. The description adds genuinely new behavioral context: the crawl is bounded to the homepage plus up to 60 sitemap pages, and it enumerates the artifact types inspected (embeds, facades, widgets, VideoObject nodes). That scope cap is the kind of limit an agent cannot get from 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?

A single long run-on sentence, front-loaded with the scope phrase, with no filler sentences. However, the density and stacked jargon (facades, page-builder widgets, VideoObject required properties) make it hard to scan, and it is not broken into purpose versus behavior.

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 signaling what data comes back by listing the extracted artifact types. It also states the crawl bound and the conditional handle behavior. It stops short of describing the return shape or the domain input format, but for a read-only scan tool this is close to sufficient.

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 description coverage is 0%, so the description carries the burden. It explains the handle parameter's effect well ('how many of the channel's videos the site carries'), but the required domain parameter is never characterized - no indication of whether it takes a bare domain, a URL, or a subdomain. Partial compensation only.

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 scope (homepage plus up to 60 sitemap pages) and enumerates what it extracts: YouTube embeds, facades, page-builder widgets, VideoObject nodes and their required properties. The phrase 'the site half of video' implicitly distinguishes it from the sibling video_channel, but it is a noun phrase rather than a clean verb+resource statement, so an agent must parse dense jargon to extract the action.

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 no explicit when-to-use, when-not-to-use, or named alternative. The 'site half of video' framing weakly implies a counterpart, but the agent is left to infer that video_channel covers the other half and that video_check is a different kind of operation. The only conditional guidance is 'with a handle', which is a parameter note rather than usage routing.

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