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

With annotations present (readOnlyHint=false, openWorldHint=true), the disclosure bar is lower, and the description usefully reveals the lack of cursor-based pagination. It does not explain rate limits, what happens on private/invalid videos, or the shape of comments returned.

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?

Two tight sentences, front-loaded with the core action and followed by the key operational caveat. No filler.

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 simple two-parameter read tool with full schema coverage and annotations, the definition covers what's needed to invoke it correctly. Only minor gaps remain around error behavior and comment fields, which an output schema would otherwise cover.

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 both parameters are already documented including the 1-100 range and default of 20. The description's note that limit bounds the returned sample and that there is no cursor adds modest value over the 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?

States a specific verb+resource ("List comments on a YouTube video") that is clearly distinct from the platform-specific comment siblings. However, it offers no further disambiguation beyond the platform implied by the name.

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?

Adds a useful practical note that limit bounds the sample because no pagination cursor exists, which implies usage for sampling rather than exhaustive retrieval. It never states when to prefer this over sibling comment tools or what prerequisites (e.g., public video) apply.

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