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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so safety and idempotency are covered. The description adds the return fields (ids, titles, channels, durations, view counts) and a cross-tool workflow hint, but doesn't discuss rate limits, pagination, or authentication requirements. With annotations carrying the safety profile, this is adequate but not rich.

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 sentences with zero waste: the first states the action and return data, the second provides a direct next-step hint. The information is front-loaded and each sentence earns 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?

Given a simple two-parameter tool with annotations covering safety, an output schema (which the description doesn't need to detail), and the description providing return fields and a workflow hint, it's nearly complete. The only gap is the lack of explicit 'limit' semantics, which could confuse an agent about result count.

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 compensate. It reveals that 'query' is a keyword string and that returned fields include durations and view counts, implying what 'limit' controls (number of results), but it doesn't explicitly describe the 'limit' parameter's effect or default. The description adds some meaning but leaves the 'limit' parameter 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 description states a specific verb 'Search' and resource 'YouTube for videos', and names the primary input 'by keyword'. It clearly distinguishes itself from sibling tools like get_channel_videos and get_playlist_videos, which are scoped to channels or playlists.

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 tells when to use this tool (to search by keyword) and names a follow-up alternative (get_youtube_transcript) for reading a video's content. It doesn't explicitly rule out other scenarios or mention when to use sibling tools like search_channel_videos, but the context is clear enough.

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