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

The readOnlyHint already declares the safe read profile, and the description adds useful behavioral context: it computes PAYE, UIF and SDL, returns gross/deductions/net/line detail, and previews payvalues overrides without storing or posting anything. It does not cover permissions, error behavior, or rate limits, but it adds meaningful context beyond the annotation.

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?

The description is front-loaded with a specific purpose, then the preview workflow, then the safety note. It is appropriately sized and easy to scan, though the final sentence slightly repeats the earlier 'without saving it' point rather than adding new information.

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 still explains the return content well: gross, deductions, net, each line, and statutory pricing. Combined with a fully described input schema and the readOnlyHint, it gives an agent enough to invoke the preview correctly and understand that nothing is persisted.

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 the input schema already documents paydate, employee, frequency, and payvalues in detail. The description reinforces that payvalues rows override saved values for preview only, but adds little syntax or meaning beyond what the schema already provides; the baseline of 3 is appropriate.

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 states a specific verb and resource ('Price a payslip') for a saved employee and immediately distinguishes it from the saving action ('without saving it'). It also names the computed outputs (gross, deductions, net, each line, PAYE/UIF/SDL), so an agent can distinguish it from save_payslip or get_payslip without opening the schema.

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 clearly says when to use the tool: to preview a change before saving with save_employee, and specifically via rows in payvalues. It names the save alternative but does not explicitly route agents to get_payslip when they want an already-saved payslip, so the alternative guidance is clear but not exhaustive.

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