update_video

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

With no annotations provided, the description carries the full burden. It discloses important behaviors: tag replacement semantics ('An empty list for tags removes all existing tags'), partial update behavior ('Omitted fields are left unchanged'), and the requirement that the video exists. It could add permission or error details, but the disclosed behaviors are material and well-covered.

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 well-structured with a brief opening statement, a clear args list with per-parameter explanations, and a return format summary. Every sentence adds necessary information, with no fluff or redundancy. The length is appropriate for the six-parameter tool.

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?

All six parameters are documented, the return object is described, and key behavioral nuances (e.g., empty tags removal, omitted fields unchanged) are covered. The presence of an output schema reduces the need to detail return structure, but the description still provides it. This is complete for effective tool usage.

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 0%, so the description is the sole source of parameter meaning. It explains each parameter in detail: video_id, title, description, tags (including empty list behavior), category_id, and privacy_status (with allowed values). This exceeds the schema's minimal type information and adds crucial semantics.

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 clearly states the tool's function: 'Updates metadata for a YouTube video identified by videoId'. This specific verb-resource pairing distinguishes it from siblings like upload_video or update_thumbnail. It also emphasizes that the video must already exist, which is a clear scope.

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 clear context: it is for updating existing video metadata, and it states prerequisites ('video must exist') and semantic rules ('Omitted fields are left unchanged'). It does not explicitly name sibling alternatives or state when not to use it, but the context is sufficient for most cases.

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