datetime.fiscal_quarter

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

Annotations already declare readOnly, idempotent and closed-world, so safety is covered. The description adds real behavioral rules beyond that: quarters are cut in 3-month steps from each country's fiscal-year start, the start day-of-month is preserved, and UK quarters begin on the 6th. It does not disclose edge-case handling (e.g. day-of-month overflow such as a 31st start), which for a date-arithmetic tool is the remaining risk.

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?

Three dense sentences with no filler: output definition, computation rule, then the exclusion. The returned value is front-loaded and the caveat is placed last where it belongs.

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?

An output schema exists, so the description needn't spell out the return shape, and the country/as_of semantics are fully covered. The one gap is that per-country fiscal-year start dates (KR Jan 1, US Oct 1, JP Apr 1, UK Apr 6) are referenced but never listed, leaving the agent to rely on the implementation for the actual anchors.

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 0%, so the description carries the full load and does so: as_of is defined as a YYYY-MM-DD reference date, and country is enumerated inline (KR | US | JP | UK) with a stated default of KR — information the schema's bare string types do not provide.

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 (구한다) and resource (회계분기), plus exactly what is returned: quarter number 1~4 and start/end dates. Naming '분기' versus the sibling datetime.fiscal_year makes the scope boundary legible without opening either 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?

Gives clear applicability context via the country parameter (fiscal-year start per jurisdiction, default KR) and an explicit exclusion: statutory filing deadlines such as VAT reporting are not computed. It stops short of naming the alternative tool (e.g. datetime.tax_period_kr) that would handle those deadlines, so the 'use instead' half of the guidance is only implied.

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