source_related

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

No annotations are provided, so the description bears the full responsibility for behavioral disclosure. It explains the operation (finding related videos) and the ordering (by number of shared tags), which is transparent about the result behavior. However, it does not explicitly state that the operation is read-only, any authentication requirements, rate limits, or potential side effects. Since 'find' implies a non-mutating query, this is largely implicit, but the description could be more explicit.

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?

The description is succinct and well-structured: a one-sentence purpose followed by a brief explanation and an argument list. Every sentence adds value, and the most important detail (the purpose) is front-loaded. It avoids fluff and is appropriately sized for the tool's simplicity.

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?

The tool has an output schema, so return values are likely documented there, and the description still notes the sorting order, which is helpful. However, it does not mention what happens when no related videos are found, nor does it specify the expected source format beyond the default. Given the relatively simple scope, the description is adequate but leaves some expected details unaddressed, such as error behavior or valid source names.

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?

The input schema provides only types and a default for source; it has no descriptions (coverage 0%). The description compensates by defining video_url as 'YouTube video URL or video ID' and noting source defaults to 'youtube.' This adds meaning beyond the schema, though it does not enumerate possible source values. Given the schema's absence of guidance, this is a solid contribution.

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 opens with a precise statement: 'Find related videos by shared tags.' It clearly identifies the verb (find), the resource (related videos), and the mechanism (shared tags), and then adds sorting criteria. This sets it apart from sibling tools like source_list or source_search, which likely handle listing or searching sources, so an agent can readily distinguish it.

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?

The description provides no guidance on when to prefer this tool over alternatives, nor any exclusions or prerequisites. It does not mention sibling tools or suggest alternative actions for different scenarios. An agent is left to infer that this is for retrieving related content based on video tags, but no explicit when-to-use or when-not-to-use guidance is given.

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