compare_channels

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes the tool's behavior by specifying the output format (subscriber count, total views, video count, winners) and constraints (max 5 channels). However, it lacks details on error handling, rate limits, or authentication needs, which are important for a tool fetching external data.

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 front-loaded with the core purpose in the first sentence, followed by output details and usage context. Every sentence earns its place by adding essential information without redundancy, making it efficient and well-structured.

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 tool's moderate complexity (fetching and comparing external data), no annotations, and no output schema, the description is adequate but incomplete. It covers the purpose, output metrics, and usage context, but lacks details on error cases, data freshness, or response structure, which could hinder an agent's ability to handle edge cases effectively.

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?

The input schema has 100% description coverage, so the baseline is 3. The description adds value by reinforcing the parameter's purpose ('Side-by-side overview comparison for multiple channels') and context ('Good for competitor analysis'), which enhances understanding beyond the schema's technical details. It does not provide additional syntax or format details, but the context is helpful.

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 purpose with specific verbs ('compare', 'returns') and resources ('multiple channels'), distinguishing it from siblings like 'get_channel_overview' by emphasizing side-by-side analysis and competitor focus. It explicitly mentions the scope (max 5 channels) and output metrics (subscriber count, total views, video count, winners).

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 provides clear context for usage ('Good for competitor analysis'), implying when to use this tool. However, it does not explicitly state when not to use it or name alternatives among siblings, such as 'get_channel_overview' for single-channel data or 'compare_videos' for video-level comparisons, leaving some ambiguity.

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