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

Goes well beyond the readOnly/openWorld annotations: it discloses that only public metadata is returned, that mediaUrls links expire after about a day, that those links require a Chrome or Edge browser User-Agent, and that the call costs 1 credit. These are exactly the operational constraints an agent cannot infer from structured fields.

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?

Four compact sentences with no filler; the field inventory, media-link behavior, and cost are each delivered once. Slightly front-loaded weakly, since the generic 'Video details' opener precedes the substantive content.

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 usefully enumerates the returned fields and explains the mediaUrls ordering and expiry, which an agent needs to use results correctly. The one remaining hole is the unexplained cache_max_age parameter, plus no note on behavior for missing or private videos.

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 50%: the url parameter is well documented in the schema itself (id or ok.ru/video link) and the description adds nothing there, while cache_max_age is undocumented in both places. The expiring-media note indirectly hints at caching behavior but never explains the cache_max_age parameter, leaving half the inputs unexplained.

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 (OK.ru video) and enumerates the exact metadata returned – title, description, channel, duration, views, likes, comments, shares, upload date – so an agent knows precisely what it gets. The leading 'Video details' is somewhat tautological, but the follow-on sentence does the real work; sibling differentiation is inherent since this is the only ok.ru video tool.

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 rather than stated: 'Public metadata' signals this fetches details rather than searching or listing, and there are no competing ok.ru video siblings to route against. However, there is no explicit when-to-use, no mention of when it is the wrong tool (e.g. for private/restricted videos), and no stated prerequisites.

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