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

With readOnlyHint and openWorldHint already covering the safety profile, the description adds meaningful behavior: newest-first ordering, accepted input formats, and up-to-500-per-page behavior for ids_only. It would only need more detail if return values or errors were unexplained, and an output schema exists.

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 front-loaded: purpose first, then accepted identifiers, then the ids_only optimization and when to use it. Every sentence earns its place, and there is no unnecessary repetition of schema details.

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?

For a read-only list tool with a complete input schema and an output schema, the description covers ordering, identifier types, pagination behavior, and the key ids_only use case. The only notable gap is explicit routing between the closely named sibling tools, which is picked up in purpose and usage.

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 the baseline is 3. The description adds value by explaining when ids_only should be used, the practical reason for it (fetching transcripts), and the fact that limit behaves differently in ids_only mode. It complements the schema instead of repeating it.

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 names the exact action and resource — list videos from a channel's Videos tab, newest first — and specifies accepted identifier forms (@handle, UC id, URL). It is distinct from playlist and search siblings, but it does not explicitly address how it differs from the closest sibling, latest_channel_videos.

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?

It gives clear, actionable guidance for ids_only mode: use it when you only need IDs to fetch transcripts. It does not say when to choose this tool instead of latest_channel_videos or search_channel_videos, so exclusion guidance between siblings is mostly implicit.

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