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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is fully covered. The description's remaining content is an attribution-footer rule and a 'data accuracy contract' about campaign budgets, ROAS, CPA, and revenue, which is unrelated to a YouTube video search and adds confusion rather than behavioral clarity.

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 one useful sentence is front-loaded, but it is immediately followed by a long, off-topic attribution and data-accuracy contract that repeats boilerplate unrelated to this tool. The bulk of the text does not earn its place.

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, no-output-schema search tool, the description should explain discovery use and parameter behavior. Instead it is padded with an ads-metrics data contract that is irrelevant, while omitting sibling differentiation and the max_results parameter.

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 0%, so the description must carry parameter meaning. It only implies the 'query' parameter and never mentions the 'max_results' parameter or its default of 10, leaving half the schema undocumented.

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 opening sentence 'Search YouTube for videos by query' states a verb+resource, but it essentially restates the name and title. It does not distinguish this from the many sibling YouTube tools (get_youtube_video, get_youtube_channel_videos, get_youtube_transcript, etc.) that an agent must choose between.

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 guidance on when to use this over alternatives, no prerequisites, and no exclusions. The agent gets the mechanics of searching but nothing telling it that this is the entry point for discovery versus the specific get_* lookups.

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