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

With no annotations supplied, the description carries the full disclosure burden. It usefully adds the per-request credit cost and the Bearer auth requirement, but says nothing about result limits, return shape, or how pagination behaves beyond the mere existence of a cursor.

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 is front-loaded in one short sentence and the cost/auth notes are compact. The 'Platform=youtube resource=keyword-search' metadata restates the tool name and a stray double period adds noise, but the overall footprint is small.

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 simple two-parameter read tool without an output schema, purpose, cost, and auth are covered, which is adequate. It is incomplete on what a result looks like and any cap on returned items, which an agent needs to plan pagination.

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 are already documented (query as 'Search text', cursor as a pagination token). The description adds no query syntax, matching behavior, or cursor semantics beyond that, so the baseline of 3 applies.

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 public YouTube videos by keyword'), which lets an agent distinguish it from hashtag-based and trend-based siblings. The distinction is implied by 'keyword' rather than explicitly contrasted, so it stops short of a 5.

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?

There is no when-to-use or when-not-to-use guidance and no mention of alternatives such as youtube_hashtag_search or youtube_trend_search, even though those siblings overlap heavily with keyword search. The only constraint conveyed is that results are limited to public videos.

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