youtube_search_videos

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

Annotations cover the safety profile (readOnlyHint, openWorldHint), so the bar is lower. The description adds genuinely valuable context the annotations lack: the ~101 quota-unit cost and the recommendation to keep queries narrow, which tells the agent to budget calls carefully. It doesn't cover pagination or the statistics returned, but the quota disclosure is meaningful.

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?

Two short sentences, front-loaded with the tool's function and then the cost caveat. No filler or restated boilerplate.

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?

An output schema exists, so return values needn't be explained, and the cost hint is valuable. But for a 5-parameter search tool with only 40% schema coverage, the description omits any parameter guidance and any sibling differentiation, leaving clear gaps.

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 only 40%, so the description should compensate but adds no parameter meaning at all. region_code and published_after are documented in the schema, but order and max_results are undocumented in both places, and nothing in the description clarifies enum choices or result limits.

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 (Search) and resource (YouTube videos) plus the return shape (with statistics). It is clear what the tool does, but it does not distinguish itself from siblings like youtube_recent_uploads or youtube_video_details, leaving the agent to infer that search is query-driven rather than feed-driven.

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 cost note ('prefer narrow queries') gives useful operational guidance, implying this is an expensive, last-resort-style call. However, it never states when to use this over the sibling tools (e.g., use recent_uploads for a known channel), so routing guidance is only implied.

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