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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses cost (1 credit), the ~1 hour validity window of the HLS playlist in mediaUrls, and the precise causes of an empty stream (DRM protection, player unavailable to a logged-out visitor). These are exactly the operational constraints an agent needs before spending a credit and before interpreting a missing stream as an error.

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 short sentences, front-loaded with the identity ('Video details and stream') followed by what is returned, the key output field's lifetime, the failure condition, and the cost. Every sentence carries non-redundant information; nothing is padding.

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 describing returns (field list, mediaUrls semantics, empty-state conditions) and even flags partial-data cases like hidden likes/comments. The only material gap is the undocumented cache_max_age parameter, which an agent may need to control caching behavior.

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 only 50%: `url` is documented in the schema, but `cache_max_age` has no description anywhere. The tool description never mentions either parameter — it doesn't restate the accepted id/URL formats or explain what cache_max_age does or how it affects the one-hour stream validity. It adds no meaning beyond the schema and leaves a parameter fully undocumented.

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 and scope: 'Public metadata for a Vimeo video' with an enumerated field list (title, description, channel, duration, tags, upload date, plays, likes, comments) plus the stream URL. That is far more specific than the title alone. It does not differentiate itself from sibling video tools on other platforms (youtube_video, dailymotion_video, etc.), but since this is the only Vimeo tool in the list, that omission costs little.

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 context is implied by 'Public metadata... for a logged-out visitor' and by the note that counts are shown only 'where the owner shows them,' but there is no explicit when-to-use / when-not-to-use guidance and no named alternative. The empty-mediaUrls conditions tell the agent what a null result means, which is useful, but it is not routing guidance.

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