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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description usefully discloses the substantive rules the computation applies (31% from 7 Oct 2026 vs 33% before, 33% on development land, €1,270 exemption, losses, 15 December deadline), which lets an agent sanity-check results. It never says the tool returns an estimated liability figure or a breakdown, and gives no indication of result precision or handling of edge cases.

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 with no filler; the rate structure and the exclusion are packed in the right order. It reads as a dense run-on, though, and the parenthetical rate history takes space that could have been spent stating what the tool returns.

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 eight parameters and no output schema, the description should clarify the return value, which it does not – an agent cannot tell whether it receives a single tax figure, a line-by-line computation, or just rule text. The tax rules it does supply compensate for much of that gap, but the output contract remains undefined.

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 baseline would be 3, but the description earns more: it explains the rate split that the 'asset' enum implies (development land at 33% regardless of date), the date-dependent rate change tied to disposalDate, and the annual exemption that exemptionUsed partially consumes. Losses are named as allowable, clarifying what the losses parameter accepts.

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 names the specific tax and the resources it applies to (disposals of shares, crypto, property other than the home), so an agent knows this is an Irish CGT computation tool. It lacks an explicit verb such as 'calculate', which is implied only by the parameter set, but the domain is unambiguous against siblings like ireland_rent_tax_credit or uk_stamp_duty_england_ni.

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 gives a concrete exclusion: 'Not for Irish/EU ETFs or funds, which pay exit tax.' That is a real routing rule an agent can act on. It does not, however, state when the tool should be preferred over a general Irish tax sibling or what prerequisites (residency, tax year) apply.

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