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

Annotations already cover the safety profile (readOnly, non-destructive, open-world), and the description adds genuinely new context: the per-call cost (1 credit) and the fact that results are paginated. It does not disclose rate limits or what the response looks like, but pricing is a meaningful addition beyond structured fields.

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 sentences, no filler; the core action is front-loaded and the pricing caveat is placed last where it belongs. Every sentence earns its place.

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?

An output schema exists, so return values need not be described, and the description covers action, scope, pagination, and cost. The one gap is the absence of explicit routing to facebook_get_comment_replies for nested replies, which an agent might need given the large sibling set.

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 every parameter (link, limit, end_cursor, include_reply_info) is already documented in the schema. The description's mention of 'pagination' is the only added hint, which merely echoes the end_cursor parameter; baseline 3 applies when the schema does the heavy lifting.

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 (Retrieve) and resource (top-level comments) scoped to a Facebook post or reel, and the word 'top-level' implicitly carves out a distinct resource from the sibling facebook_get_comment_replies. It stops short of naming that sibling explicitly, so it is clear but not maximally discriminating.

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 'top-level' qualifier hints that reply retrieval is a separate operation, but the description never says when to use this tool vs. facebook_get_comment_replies or advertises any prerequisites. Usage is implied rather than stated.

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