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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuine interpretive context beyond that: it computes both employer and employee notice, and warns that the result is a legal minimum a contract may exceed — which affects how the agent should present the answer.

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 sentences, no filler, with the core computation stated first and the contract caveat following. Every clause carries meaning.

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?

Output schema exists, so return values need no explanation, and the three-parameter surface is simple. The remaining gap is selection context: a sibling named 'check_notice_period' sits next to this tool and the description gives no basis for choosing between them.

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%, with 'given', 'nation' and 'started' each documented including date format and an enum for nation. The description restates the same inputs ('start date', 'day notice is given', 'any UK nation') without adding format or edge-case detail, so 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?

A specific verb ('work out') and resource ('the least notice the law requires to end employment'), with the scope of both directions (employer and employee) stated. However, it never distinguishes itself from the sibling 'check_notice_period', which by name appears to overlap heavily — an agent cannot tell which one to pick.

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?

The second sentence ('A contract can require more notice, never less') establishes that this returns a statutory floor rather than the actual contractual notice, which is a useful scope boundary. But there is no explicit when-to-use, when-not-to-use, or routing to the similarly named 'check_notice_period' sibling.

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