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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety bar is low. The description earnestly adds beyond that: the returned/omitted field set, one-page-per-call pagination, and that results are gated by token permissions. It omits ordering behavior and what happens when siteIds spans many sites.

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 compact sentences with no filler, and the field-scope statement leads. Field enumeration is slightly listy but each clause carries information the schema does not.

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 6 parameters, nested date-range objects, no output schema and near-zero schema coverage, the description leaves key decisions unexplained: the required siteIds semantics, includeDeleted's effect on results, and how the two date ranges differ. It adequately covers return shape but not invocation for a fairly complex signature.

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 only 17% and the description does not compensate: siteIds (the sole required param), pageSize, includeDeleted, createdDateRange and paymentDateRange are all undocumented in prose. 'Payment amounts, dates' and 'one page per call' only loosely gesture at the date-range and paging params.

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 the resource's fields (amounts, dates, method, currency, status) and explicitly scopes out notes, bank details, child records and metadata, so an agent can tell it targets payment records rather than invoices or purchases. It never states the action (list/retrieve) explicitly, relying on the title, but the field-level scope makes it distinguishable from siblings.

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 indication of when to choose this over famly_list_invoices, famly_list_purchases or the other list tools. 'One page per call' hints that callers must page, and the token-permission caveat sets expectations, but neither is a usage decision rule.

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