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

Annotations declare readOnlyHint=true, but "Replies to one Facebook comment" reads as a write action (posting a reply), which contradicts that. The description adds only a credit cost and says nothing about pagination, cursors, permissions, or what data comes back.

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?

It is short with no padding, but the brevity is under-specification rather than economy: the single sentence creates ambiguity instead of resolving it, and the credit note is appended parenthetically without context.

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 four-parameter, paginated, open-world tool with no output schema, the description should clarify that it lists replies, how the cursor/feedback_id/expansion_token fit together, and what is returned. It supplies none of this and misleads on the read/write distinction.

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 four parameters are already documented in the schema; the description adds no meaning beyond them. Baseline 3 applies, and notably the description never mentions that cursor implies paged retrieval.

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?

"Replies to one Facebook comment" restates the tool name and is ambiguous about the operation: it reads like posting a reply, while the parameter set (cursor, comment_id, feedback_id, expansion_token) indicates retrieving replies. It does not distinguish the tool from the sibling facebook_comments.

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 when-to-use guidance and no alternatives are named, even though facebook_comments is an obvious sibling that an agent must choose between. The only added instruction is a cost note, not a usage condition.

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