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

Annotations already declare readOnlyHint and destructiveHint, giving a baseline safety profile. The description adds useful behavioral context: it returns 'current' live results, uses cursor-based pagination, and explicitly states that 'Each page is one metered request.' This goes beyond the annotations and helps agents anticipate cost.

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 compact and front-loaded: one summary sentence, one sentence listing applicable filter dimensions, and one sentence describing pagination and metering. Every sentence the main purpose, the main options, and the key usage constraint without wasted prose.

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 read-only search tool with an output schema, this description covers the primary query intent, filter semantics, and cursor cycle. It still leaves small gaps such as the meaning of limit/newline and what terminates pagination, but these are partially inferable from schema defaults and the output schema, so the description is close to complete.

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 schema has zero description coverage, so the description is the main provider of meaning. It maps many parameters thematically — upload window, popularity, result type, duration, country, language — and explains ‘pass next_cursor back as cursor for the next page.’ However, it does not clarify the `q`, `limit`, or `cursor` values beyond terms already in the schema, leaving some parameter semantics to be inferred from names and enums.

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 a specific verb and resource: 'Search current YouTube results' with filters and pagination. It distinguishes the tool generically from sibling search tools like search_creators and get_youtube_video, but does not explicitly name those alternatives or narrow the resource to videos.

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 gives clear context for when to use this tool: searching YouTube results with discovery filters and pagination. However, it provides no explicit guidance on when not to use it or how it compares to sibling tools such as search_creators, get_youtube_video, or semantic_search_creators, so the agent must infer the appropriate selection.

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