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

Annotations already declare read-only, idempotent, open-world, non-destructive, so safety is covered. The description adds genuinely new behavioral facts: billing cost ('Uses 1 extraction') and a plan-dependent truncation rule ('On the free plan it returns the first 10 entries and the total'), which an agent cannot infer from structured fields. It stops short of describing ordering guarantees beyond 'site order' or failure behavior for non-listing URLs.

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?

Three short sentences, zero filler, with the resource and scope front-loaded and the chaining instruction placed before the cost/limit caveats. Every clause carries operational information.

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 the return payload, and it does: entry URLs in site order, the next page if present, and the total on the free plan. Combined with the cost disclosure and the handoff to extract_video_metadata, an agent has everything needed to invoke and chain it.

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% and the single parameter is documented as a URI, so the baseline would be 3. The description earns the extra point by constraining what that URL may be — a category, archive, playlist, or listing page — narrowing the accepted input beyond the schema's generic 'Public URL of the listing page'.

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 verb and resource ('return the URLs of the individual entries' of a 'category, archive, playlist or listing page'), and enumerates the page kinds it accepts, which no sibling does. An agent can distinguish it from extract_video_metadata because the description explicitly frames this tool as the producer of URLs that the other consumes.

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?

Gives clear context for when to reach for this tool and names the follow-up step ('Pass those URLs to extract_video_metadata'), so sequencing is unambiguous. It does not state any exclusion or when-not-to-use condition, which keeps it short of a 5.

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