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

Beyond the annotations (readOnly, idempotent, openWorld, non-destructive), the description discloses that X may cap retweeter lists for widely reposted posts, that like data does not exist, and the exact billing model ('1 credit + 1 credit per user_result returned'). Those are cost and completeness traits an agent cannot derive from the 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?

It is front-loaded with the purpose and every sentence carries information (cap behavior, likes unavailability, billing, pagination). The pagination advice appears twice — once as 'Paginate with `meta.nextCursor`' and again in the closing sentence — which is a minor redundancy.

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 available, the description still tells the agent what comes back ('accounts... as X lists them'), where the cursor lives in the response, that results may be truncated by X, and what each call costs. That is enough to invoke and loop the tool 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 `id`, `limit`, and `cursor` are already fully documented, including the cursor's rejection with 400 if reused across requests. The description's pagination sentence restates what the cursor schema already says, adding no new syntax or format semantics, so the baseline of 3 applies.

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 first sentence names a specific verb ('Get') and resource ('accounts that reposted an X post'), which is precise enough to separate it from sibling endpoints such as get_x_quotes, get_x_replies, and get_x_user_posts without opening any schema.

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 description tells the agent that pagination means calling again with `cursor` set from `meta.nextCursor`, and it rules out an adjacent use case by noting that liker data is unavailable because X made likes private. It stops short of naming alternative sibling tools (e.g. get_x_quotes) for the related-but-different question of who quoted the post.

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