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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so safety is covered. The description still adds genuine behavioral context beyond that: bank payment details are redacted from the response, and the returned field set varies by region, both of which affect how an agent should interpret results.

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?

One tight sentence plus the HTTP route; the payload description is front-loaded and nothing is padded. The trailing endpoint path is mildly redundant with the tool name but is compact and unambiguous.

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 no output schema, the description carries the return-value burden and does so reasonably: it names the main totals categories, warns the field set is region-dependent, and notes bank details are stripped. It omits pagination/response-shape details, but for a two-parameter read 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 description coverage is 100% and both required parameters (business_id, pay_run_id) are documented in the schema, including the pointer to keypay_list_businesses. The description adds no parameter syntax or format detail, so the baseline of 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 and resource ('Per-employee totals of a pay run') and enumerates the fields returned (gross, net, tax withheld, super), which is much more informative than the bare title. It does not, however, differentiate itself from the close sibling keypay_get_pay_run_summary, leaving the agent to infer the boundary.

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?

There is no when-to-use guidance at all: no condition, no prerequisites, and no mention of the neighboring tools (pay_run_summary, pay_run_payslips) an agent would have to choose between. The scope is implied by the name and path only.

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