tilwhen date engine

Add calendar days to a date

add_days

Read-onlyIdempotent

The date N whole calendar days after a date (exclusive counting: the start date is day 0).

Input Schema

TableJSON Schema

Name	Required	Description	Default
`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)	today
`days`	Yes

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

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

First observedJul 26, 2026

TDQS

B3.1/5.0

Behavior3/5

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

Annotations already indicate read-only and idempotent behavior. The description adds that counting is exclusive (start date is day 0), but lacks details on timezone handling, error cases, or range limits (provided in schema).

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

Conciseness3/5

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

Single sentence is concise but slightly terse. It is front-loaded but could be expanded slightly for clarity without becoming verbose.

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

Completeness2/5

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

Despite having an output schema, the description lacks important context such as how timezone affects the result, default behavior for 'today', and edge cases. For a date math tool, it feels incomplete.

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

Parameters2/5

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

Description adds no information beyond the input schema. Parameters like 'tz' and 'date' are only documented in the schema; the description does not clarify their usage or defaults beyond what's in the schema.

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 the tool computes a date offset by N calendar days with exclusive counting. It distinguishes from siblings like 'subtract_days' and 'business_days'.

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

Usage Guidelines2/5

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

No explicit guidance on when to use this tool versus siblings such as 'business_days' or 'next_occurrence'. The description only details the counting method.

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

All tilwhen date engine tools Inspect

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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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