Rank outliers across several channels

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

With no annotations, the description carries the burden of behavioral disclosure. It discloses the cost ('Costs about 5 quota units per channel') and explains the normalization basis ('measured against its own channel's baseline'). It implies read-only behavior via 'scan', but does not explicitly confirm non-mutating behavior or describe return format. Overall, it adds meaningful context beyond the schema.

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?

Three short sentences, each serving a distinct purpose: what it does, when to use it, and cost. No filler or redundancy.

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?

The core function and usage context are clear, and the cost note is helpful. However, with no output schema and two undocumented params (depth, limit), the description leaves significant gaps in understanding the tool's full behavior and return values. It is adequate but not complete.

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 33% (only 'channels' has a schema description). The description rephrases 'channels' as 'several YouTube channels' and adds niche/competitor context, but provides no explanation for 'depth' or 'limit'. The enum values for 'depth' (light/standard/deep) remain completely undefined, so the description does not compensate for the low schema coverage.

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 the tool's function: 'Scan several YouTube channels at once and return the strongest outliers across all of them, each measured against its own channel's baseline.' This gives a specific verb, resource, and scope, and distinguishes it from single-channel analysis.

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?

Explicit usage guidance is provided: 'Call this when the user wants to see what is working across a niche or a set of competitors rather than one channel.' This clearly indicates when to use it, though it does not name alternative sibling tools explicitly, only contrasts with single-channel use.

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