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

With no annotations, the description carries the full behavioral burden and does disclose two meaningful traits: an auth requirement (Authorization: Bearer <api_key>) and a cost model (1 credit per page). It still omits rate limits, sorting/ordering behavior, and whether results are paginated beyond the stated depth, which keeps it short of a 5.

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 purpose and page size lead the sentence, which is good, but the tail is boilerplate redundancy: 'Priced per page' is restated by 'Costs 1 credit(s)' and 'Credits unit: page', and 'Platform=youtube resource=search' adds nothing for an agent. A stray double period also signals templated, unedited text.

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 two-parameter read tool with no output schema and no annotations, the description is adequate: auth, cost, and approximate result volume are present. It stops short of describing result fields, ordering, or how to disambiguate from the many sibling search/video tools, which is the main remaining gap.

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 both parameters (keyword, depth) are already documented, and the description only restates the depth default and adds the ~20-per-page output estimate. Baseline 3 is appropriate when the schema does the heavy lifting.

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+resource ('Search public videos by keyword') and adds scope via the ~20-per-page estimate, so an agent knows this is a keyword-driven public video search. It does not, however, distinguish itself from near siblings like youtube_videos, tiktok_search, or threads_search, leaving that routing to inference.

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 only usage guidance is an implicit default page count; there is no statement of when to choose this over youtube_videos, youtube_channel, or other platform search tools, and no preconditions beyond the generic auth note.

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