Comments

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

Beyond the annotations (destructiveHint=false, openWorldHint=true), the description adds meaningful operational context: it consumes paid credits, requires confirm=true, and is capped at ~1,000 top / 7,000 newest comments. It also preempts confusion about the non-readOnly POST by noting it does not publish to social platforms. It stops short of describing error/pagination failure behavior, so not a 5.

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?

Purpose is front-loaded in the first sentence, followed by ordering/pagination, limits, and cost/auth constraints. All four sentences carry distinct, non-redundant information with 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?

With no output schema, the description compensates by listing the returned fields and the retrieval caps, and it covers the credit/confirm requirements. The one notable gap is behavior on missing or expired continuation tokens, but overall it is complete enough to invoke correctly.

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 description coverage is 100%, so all five parameters are already documented in the schema. The description restates 'ordering by top or newest' and continuationToken but adds no syntax, format, or edge-case detail beyond the schema, making the baseline 3 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 states a specific verb and resource ('Fetches comments and replies from a YouTube video') and enumerates the returned fields (text, author, like count, reply count, publish date). It is distinct from generic siblings, though it does not explicitly name youtube_comment_replies as the alternative for reply retrieval, which keeps it short of a 5.

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 surfaces a real precondition ('requires confirm=true', credit consumption) and describes ordering/pagination options, so usage is implied. However, it never states when to choose this tool over youtube_comment_replies or youtube_transcript, leaving the routing decision to inference.

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