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

The description discloses billing cost but does not mention read-only behavior, error handling, or what happens if the video ID is invalid. With no annotations, the description fails to provide a complete behavioral profile beyond the cost.

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 extremely concise, packing the return type, definition, group, and billing into a single sentence with zero filler. It is well-structured and front-loaded.

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?

As a simple getter with one parameter and no output schema, the description partially conveys the return type but does not explicitly state that it returns the channel ID for the given video. It also does not clarify whether the parameter is required, despite the schema showing zero required parameters, leaving a critical gap.

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 schema already fully documents the 'id' parameter with example and format, meeting the 100% coverage baseline. The description adds no parameter-specific meaning, so the baseline score of 3 is appropriate.

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 defines what a channel ID is but lacks an explicit action verb like 'gets' or 'returns'. The title and name imply the operation, but the description itself only describes the output value, making the purpose vague without relying on context.

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?

No guidance is provided on when to use this tool over sibling tools like get_info_channelName. The only hint is 'Group: Specific video Info,' which is a classification rather than actionable selection criteria.

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