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

Annotations already mark the call as read-only and non-destructive, so the description does not need to restate that. It adds useful behavioral nuance by warning that payment processing is unsupported and ProcessPayment must be omitted or false, which prevents an agent from attempting write-like behavior through this read tool.

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 short sentences with the core action front-loaded and the one non-obvious constraint placed second. There is no filler or repetition of schema details.

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?

The tool is a simple single-resource lookup with only two parameters and no output schema, so the description supplies enough operational context. It might have named search_payments as the companion for finding payments without an Id, but that is a minor gap.

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 100%, so id and company are already documented. The description adds only that lookup is 'by Id', which reinforces the schema but does not add format, syntax, or interaction details beyond it.

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 identifies a specific verb-resource pair ('Get a single payment from QuickBooks Online by Id') and clarifies the resource type ('accounting record of a customer payment already received'). This clearly distinguishes it from search-style siblings and other get_* tools like get_bill_payment.

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?

'By Id' and 'single payment' indicate this is for retrieving one known record rather than listing/searching. The explicit warning that payment processing is not supported and ProcessPayment must be omitted/false gives a clear when-not condition, though it does not name an alternative tool for processing payments.

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