Search YouTube videos

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

With no annotations provided, the description carries the full burden and discloses meaningful traits: 'no API key' signals authentication requirements, and the explicit 'Returns id, title, channel, published, views, duration, snippet per hit' describes the response shape. It does not mention rate limits, pagination, or error behavior, but the disclosed return fields and filter effects are substantial for a search tool.

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 short sentences, each earning its place: action and authentication, return shape, then filter guidance. Front-loaded with the core verb and resource. No filler or 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?

For a 5-parameter search tool with no output schema and no annotations, the description is fairly complete: purpose, auth trait, per-hit return fields, and filter guidance. It does not explicitly describe the overall response container (e.g., array vs. object) or pagination, but the field list and parameter schema fill most gaps an agent would need to invoke it correctly.

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 the baseline is 3. The description goes beyond the schema by mapping two parameters to concrete use cases ('uploadDate for recency, sortBy view_count to find what performs'), adding semantic meaning to the enum choices. It does not describe maxResults or duration, but those are already clear from the schema.

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?

States a specific verb and resource ('Search YouTube for videos') and immediately differentiates from sibling tools by the action of searching. The added '(no API key)' and field-list detail confirm it is the general search tool, not get_video or get_channel_videos. Even without naming siblings, the core purpose is unambiguous.

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?

Gives clear context for when to use filters ('uploadDate for recency, sortBy view_count to find what performs'), which is actionable usage guidance. It does not explicitly contrast with sibling tools or state when not to use this tool, but the search-vs-single-item distinction is strongly implied by the title and description.

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