get_video_metadata

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

The annotations already indicate readOnlyHint=true and openWorldHint=true, which align with the description stating it returns metadata. The description adds value by detailing the returned fields (snippet, contentDetails, statistics), surpassing what annotations provide, and does not contradict them.

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 a single, well-structured paragraph. It front-loads the purpose, then lists return fields and usage modes. Every sentence adds value, with no redundancy.

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?

Given the presence of an output schema and 100% schema description coverage, the description is complete. It covers both lookup modes, parameter usage, and return structure, leaving no gaps for effective tool use.

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 100%, so baseline is 3. The description adds meaning by clarifying that video_ids are comma-separated, chart_type='mostPopular' triggers trending, and mentions max_results default of 5, improving upon the schema's basic descriptions.

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 it fetches full metadata for YouTube videos by ID or retrieves the most popular videos chart. It specifies the verb 'Fetch' and the resource 'video metadata', distinguishing from sibling tools like get_channel_metadata and get_video_transcript.

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 explains two use cases: lookup by video_ids or using chart_type='mostPopular'. It implies when not to use (e.g., if you need a transcript, use a different tool), but does not explicitly list alternatives from the sibling context.

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