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

Annotations already establish this is a read-only, closed-world calculation, so the bar is lower. The description adds real value beyond them by naming the authoritative basis (official means test, Department rate table) and versioning the rules by period (July 2026, July 2027 thresholds). It does not state that inputs are optional/default to zero or that the result is an estimate rather than an entitlement determination.

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 front-loaded sentence that opens with jurisdiction, verb, and resource, then layers the means-test detail in a parenthetical. Dense and wasteful-free, though the nested thresholds make the parenthetical hard to scan and slightly delay the core statement.

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 7-parameter means-test calculator with no output schema, the description should say what comes back (weekly rate, whether an eligibility verdict is included) and that unset parameters default to zero. It covers the inputs and their legal basis well but leaves the return shape entirely unstated.

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 baseline would be 3, but the description supplies meaning the schema lacks: the income disregard figures (€1,000/€2,000, then €1,150/€2,300) that explain how earn1/earn2 and period interact, plus a reference to savings bands underpinning 'capital'. It still does not explain the couple/aged66/caringForTwoOrMore rate escalation explicitly.

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?

Names a specific verb ('estimate') and a specific resource ('the weekly Carer's Allowance') scoped to Ireland, and grounds it in the official means test. The named benefit distinguishes it clearly from siblings such as ireland_fuel_allowance or ireland_working_family_payment without needing to open any 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?

Usage is implied by the tool name and the 'estimate' framing, but there is no explicit when-to-use guidance, no when-not-to-use condition, and no pointer to alternatives like ireland_what_can_i_claim or ireland_where_to_put_savings. An agent can infer the purpose but must decide routing on its own.

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