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

No annotations are provided, so the description carries the full burden. It discloses what the tool processes (recent uploads, packaging, titles), what it evaluates (niche demand vs. top-performing videos), and its output (90-day action plan). It also explicitly warns about slow execution time. It does not explicitly mention payment or read-only behavior, but these are at least partially covered by schema descriptions and the audit nature of the tool.

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 description is compact and well-organized: purpose first, then input expectations, process details, and a latency warning. Every sentence contributes new information with no fluff or repetition.

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 the output schema is provided and all parameters are documented, the description completes the picture by stating the tool's purpose, input types, key processing steps, output type, and the important 'up to 5 minutes' latency caveat. An agent has enough context to select and invoke this tool correctly without further assumptions.

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 coverage is 100%, so all three parameters are documented in the schema. The description repeats guidance for channel_input ('Give a channel URL, @handle, or channel ID') but adds no additional parameter-level meaning beyond the schema. This matches the baseline score for well-covered schema descriptions.

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 clearly states a specific verb and resource: 'YouTube channel growth audit' and enumerates concrete outputs (packaging grades, rewritten titles, niche demand validation, 90-day action plan). It is distinct from sibling tools like analyze_youtube_topic or search_and_rank_videos because it targets a full channel-level growth audit rather than a narrower analysis or search.

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 communicates when to use the tool: when a user wants a channel growth audit with actionable recommendations. The 'Slow call... allow up to 5 minutes' warning provides an important timing consideration. However, it does not explicitly name alternatives or state conditions when another sibling tool would be a better fit.

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