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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds a hard eligibility constraint not present in any structured field — AU, CA and UK companies only — which prevents failed calls. Return shape and not-found behavior remain unstated.

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 dense sentences with no filler: the action and lookup key come first, the usage condition second, and the domain/region constraints last. Every clause carries information an agent needs.

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 single-record read with no output schema, two fully documented parameters and readOnly annotations, the description covers purpose, routing and regional eligibility. Minor gaps (error behavior when the Id or region is invalid) keep it from being fully self-contained.

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 both 'id' and 'company' are fully documented in the schema already. The description only restates the by-Id lookup and adds no format, prefix, or multi-company disambiguation detail beyond what the schema provides, so the baseline 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?

States a specific verb+resource+key ('Get a single tax payment from QuickBooks Online by Id') and narrows the domain to sales tax payments/refunds on filed returns. The AU/CA/UK eligibility clause further disambiguates it from the sibling search_tax_payments and other get_* tools.

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?

Gives a clear routing rule: use this only 'when no search or write answer already holds it,' which steers the agent toward search_tax_payments first. It stops short of naming the alternative tool explicitly or stating when-not conditions beyond that one clause.

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