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

With no annotations provided, the description carries full burden. It discloses pay-per-call via x402, no account/API key, and that unresolved channels or naive timestamps return errors without charge. This provides critical behavioral context beyond basic functionality.

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 a single, well-structured paragraph that front-loads the purpose and efficiently covers usage, return values, pricing, and error handling. Every sentence adds value with no wasted words.

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 no output schema, the description explains return fields (new videos ids/titles/times) and pagination cursor. It addresses pricing and error states, making it complete for a tool of this complexity without needing additional context.

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 0%, so description compensates by explaining the three parameters: channel (required), since (ISO 8601 timestamp), and since_video_id (optional cursor). It clarifies their usage and mentions the output new_video_id for pagination, adding meaning beyond the bare schema.

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 lists new videos on a YouTube channel since last poll, with a specific verb ('list') and resource ('new channel videos'). It distinguishes from sibling tools like get_youtube_transcript and summarize_youtube_video, which serve different functions.

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 explains when to use the tool (pass channel URL/@handle/id, optional cursor) and how to paginate with new_video_id. It notes error conditions and pricing but lacks explicit alternatives or when-not-to-use guidance, though siblings are clearly different.

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