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

The "(1 credit)" note is a genuine behavioral disclosure not present in the annotations and is valuable for cost-aware planning. However, the description never confirms it is a paginated read (that detail lives only in the cursor schema field) and the verb-less phrasing sits uneasily next to readOnlyHint=true, which risks an agent misreading it as a write action.

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 short clauses with no filler, so nothing is wasted, but the brevity is under-specification rather than disciplined concision. The resource scope is front-loaded while the action and return behavior are absent entirely.

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 tool with no output schema, the description should at least indicate that it returns a list of comments with pagination, and it should distinguish itself from instagram_comment_replies. Neither is covered, leaving only the credit cost as extra context beyond the schema.

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% and the schema already explains url, the recent/popular enum, and that cursor comes from data.cursor. The description adds nothing beyond that, which is acceptable at full coverage but is the baseline rather than an enhancement.

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?

"Comments on a post or reel" names the resource and scopes it to a post or reel URL, so the subject matter is clear. But it omits a verb, leaving it ambiguous whether the tool fetches comments or posts a comment, and it gives no differentiation from the adjacent instagram_comment_replies sibling.

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 on when to use this versus instagram_comment_replies or facebook_comments, and no prerequisites such as whether a public account or login is required. The only usage-adjacent information is the cost note.

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