youtube_video_details

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

With no annotations, the description carries the full burden, and it does disclose two non-obvious behavioral facts: no YouTube Data API key or quota is required, and each call is billed to the caller's Apify account at ~$0.001 per video. What it omits is failure behavior for invalid/private IDs and any rate-limit context, so it is strong but not complete.

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?

Two sentences, both earning their place: the first front-loads what is returned and the input domain, the second front-loads cost. No filler, no restating of the tool name.

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 3-parameter, single-purpose scraper, the description covers purpose, input shape, pricing, and auth context. It also enumerates returned fields, which partially substitutes for the missing output schema, though error cases and per-call limits remain undocumented.

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 100%, so region, videos, and language are already fully documented in the schema, including accepted ID/URL formats and localization semantics. The description adds no parameter-level meaning beyond that, making the baseline 3 the correct score.

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 ('returns views, likes, description, tags, category, channel and comment count for any YouTube video URL or ID') and names its input domain. It is clear what the tool does, though it never differentiates itself from siblings like youtube_search_scraper or youtube_comments_scraper.

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 input contract — an agent should reach for it when it already has a video URL/ID. However, there is no explicit when-to-use or when-not-to-use guidance, and no mention of how it relates to the search, channel, or comments siblings in the same family.

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