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

Annotations already cover the read-only and closed-world profile, and the description adds genuinely new operational facts: an authentication prerequisite ('Needs the owner signed in') and the constraint that receipts/invoices are not available from this tool because Stripe emails them. It stops short of describing result ordering, pagination, or what an empty account returns.

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 sentences, front-loaded with the returned resource set, then routing and auth constraints — no filler. The first sentence's dense enumeration is slightly heavy but every element maps to a distinct returned entity.

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 parameterless read tool with no output schema, the description carries the return-value burden and does list order fields, plus useful scope exclusions and the sign-in requirement. It is less explicit about the shape of subscription payments, renewal-eligible licenses, and upgrade offers, so an agent still has gaps about the full payload.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline of 4 applies. The parenthetical field list is return-value information rather than parameter guidance.

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 description enumerates exactly what is retrieved: orders (with fields id, date, what, amount, status), subscription payments, renewable-update licenses, and upgrade offers. The verb is only implicit (the noun phrase 'The account's orders...'), but the resource set is specific enough to distinguish it from siblings like list_owned, list_sites, or get_license.

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 explicitly routes one class of request elsewhere — 'to cancel a subscription or change a card, call billing_portal_link' — and rules out receipts/invoices since Stripe emails those. However, it gives no positive trigger for when to call this versus get_license, check_updates, or renew_updates, which overlap with the 'licenses whose updates can be renewed' content.

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