tilwhen date engine

Business-day calculations

business_days

Read-onlyIdempotent

Span mode (from+to): business days between two dates, exclusive of the start day, inclusive of the end day. Add mode (days, optional date): the date N business days away. Optional holiday jurisdiction or custom calendar, and a selectable working week.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`to`	No	ISO date YYYY-MM-DD, or "today" (resolved in tz)
`tz`	No	IANA timezone that defines "today" (e.g. Africa/Kampala). Default UTC.	UTC
`date`	No	ISO date YYYY-MM-DD, or "today" (resolved in tz)
`days`	No
`from`	No	ISO date YYYY-MM-DD, or "today" (resolved in tz)
`workweek`	No	Working week. Default mon-fri (Sat+Sun weekend).
`jurisdiction`	No	Holiday jurisdiction id: US, GB, GB-SCT, GB-NIR, IE, FR, CA, AU, UG (alias UK for GB). No default: omit for no holiday calendar.
`customHolidays`	No	Custom organizational holiday calendar as ISO dates (mutually exclusive with jurisdiction)

Output Schema

TableJSON Schema

Name	Required	Description	Default
`answer`	Yes	The calculated answer (kind-discriminated)
`receipt`	Yes	Auditable receipt: inputs, timezone, convention, workweek, holiday calendar, exclusions, versions, stable result ID

TDQS

A4.7/5.0

Behavior5/5

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

The description adds significant behavioral context beyond the annotations: exclusive start day, inclusive end day for span mode; resolution of 'today' in timezone; working week options; and holiday customization. Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the description supplements with operational details.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences packed with information, front-loaded with the key distinguishing feature (span vs add modes). Every phrase earns its place, with no redundancy or filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the complexity (two modes, 8 parameters, optional holidays), the description covers the essential behavior for both modes and mentions all configurable options. With an output schema present, return values need not be explained. It is sufficient for an agent to understand when and how to use this tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 88%, so many parameters are already explained. The description adds value by explaining how parameters relate to modes (from+to for span, days+date for add). However, it does not detail the interaction between jurisdiction and customHolidays or the default workweek, leaving some semantics implicit.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states two modes (span and add) with specific verbs ('business days between', 'the date N business days away'). It distinguishes itself from siblings like 'days_between' and 'add_days' by focusing on business day calculations with holiday and working week options.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage scenarios via the two modes but does not explicitly contrast with siblings. For example, it does not state 'use days_between for calendar days' or 'use this for workday calculations'. While the context is clear, explicit when-not-to-use guidance is missing.

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

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TDQS

A4.1/5.0

Disambiguation5/5

Each tool targets a distinct date operation: calendar addition/subtraction, business days, days between, holidays, invoice due, next occurrence, natural language parsing, and an explainer. No two tools overlap in purpose; descriptions clearly differentiate them.

Naming Consistency5/5

All tool names follow a consistent pattern: lowercase with underscores, predominantly verb_noun (add_days, parse_date_query) or noun_phrase (business_days, invoice_due). The naming is uniform and predictable.

Tool Count5/5

With 9 tools, the server is well-scoped. Each tool addresses a core date calculation need without redundancy or bloat. The count is appropriate for a focused date engine.

Completeness5/5

The tool surface covers all essential date operations: calendar arithmetic, business days, holidays, payment terms, next occurrences, and natural language queries. No obvious gaps remain for common date calculations.

Resources

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