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

Annotations already declare readOnlyHint and openWorldHint, but the description adds non-obvious value: no public comments so commentCount is null, and a 1-credit cost. That's real behavior an agent couldn't derive from annotations. Return fields aren't covered, but with an undocumented openWorld read that gap is modest.

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 tight sentences: purpose first, field list second, then the two caveats (null comments, credit cost). No filler, and the most surprising fact (null commentCount) is called out.

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 lists return fields and explains why commentCount is null, plus the cost. The only meaningful gap is the unaddressed cache_max_age parameter, which leaves one behavior unexplained.

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%: `url` is well documented with accepted id and URL formats, but `cache_max_age` is undocumented in both schema and description, and the description adds nothing about it. Baseline 3 is appropriate given the schema already carries the strong url guidance.

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 verb (fetch details) and resource (a Dailymotion video) and enumerates the fields returned, so it clearly differs from dailymotion_transcript and dailymotion_channel. However, it doesn't explicitly contrast with siblings like dailymotion_search, which also surfaces video data.

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 (look up one video's metadata by id/URL), but there's no explicit statement of when to choose this over dailymotion_search or dailymotion_transcript, nor any exclusions or prerequisites. The reader must infer the routing.

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