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

Annotations already declare a read-only, idempotent, closed-world, non-destructive operation, so the safety profile is covered. The description adds genuine value beyond that by disclosing the computational basis used (the 40-hours-in-5-weeks rule, a day's pay, or one fifth of weekly pay), telling the agent what logic drives the answer rather than merely that it is a safe read.

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?

A single sentence with the entitlement question front-loaded and the outcome rules parenthetically appended; no filler, no repetition of the title, and nothing that could be cut without losing 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 must convey what comes back, and it does at a high level: an entitlement determination plus the amount basis (a day's pay or one fifth of weekly pay). What is missing is the precise shape of the result (a boolean plus a computed euro figure) and any note that casual workers are covered via 'part_time', though the schema carries that mapping.

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%, so every parameter is already documented with units, defaults, and the casual-worker mapping. The description's mention of the 40-hours-in-5-weeks rule and the one-fifth-of-weekly-pay rule loosely corresponds to 'hours_last_5_weeks' and 'weekly_pay', but it adds no format, averaging, or edge-case detail beyond the schema, 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 ('Check whether...is entitled...and what they are owed'), the resource (public holiday pay in Ireland), and the worker scope (full-time, part-time, casual). The entitlement-calculation framing distinguishes it from sibling 'irish_public_holidays', which by name is a holiday listing rather than a pay calculator.

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?

Usage is clearly implied — you call it to determine Irish public holiday pay entitlement and amount — but there is no explicit when-to-use/when-not statement and no reference to alternatives such as 'irish_public_holidays' or 'temp_worker_cost_ireland'. The agent must infer the routing from names alone.

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