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

With no annotations, the description carries the full burden. It usefully discloses sort order ('newest first'), that filters are optional, and roughly what is returned (email, status, plan, amounts), but says nothing about pagination/limit behavior, permissions, or result caps.

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?

Three short sentences, front-loaded with the core action and ordering, then filters, then return content, then alternatives. No filler and every clause carries information.

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?

No output schema or annotations, so the description does well to name return fields and alternatives, but the two undocumented parameters (limit, include_samples) leave a gap for a list tool where pagination matters.

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 0%, so the description must compensate. It adds real meaning for three of five params (app_id, status, payment_type as optional filters), but 'limit' and 'include_samples' are left entirely unexplained in both schema and description.

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+resource ('List subscriptions/registrations'), a sort order ('newest first'), and the filterable dimensions. It explicitly names the sibling tools it is not (get_customer, revenue_summary), so an agent can route without opening schemas.

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 gives clear routing conditions: get_customer for a single user, revenue_summary for totals. It does not address when to prefer this over other list-style siblings (list_recent_payments, list_recent_cancellations, list_plans), so the guidance is clear but not exhaustive.

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