# tilwhen date engine (remote · mcp.tilwhen.com)

Deterministic date arithmetic with auditable receipts: business days, due dates, holidays.

- Trust score: 76/100 (medium)
- Change this week: +6
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-08-03

## Components

- remote · `mcp.tilwhen.com`: 76/100 (this document), [markdown](https://verifymcp.io/servers/com-tilwhen-tilwhen/mcp.md), [page](https://verifymcp.io/servers/com-tilwhen-tilwhen/mcp)

## Channel facts

- Endpoint: `https://mcp.tilwhen.com/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `1.0.0`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-08-03.

- **Endpoint Security**: 80/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one.
  - HTTPS is enforced; there's no plaintext access path.
  - The HSTS (Strict-Transport-Security) header is present.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 82/100
  - 100% of prompts and resources have a non-trivial description (not blank, and not just the item's name).
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 1643 tokens (~136/item across 12 items; 9 tools + 3 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 27/100
  - Stability observed for 8 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 90/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 65% of tool parameters carry a description.
  - Structured output schemas are declared (100% of tools); any adoption earns full credit.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

### Claude

```bash
claude mcp add --transport http com-tilwhen-tilwhen https://mcp.tilwhen.com/mcp
```

### Codex

```toml
[mcp_servers.com-tilwhen-tilwhen]
url = "https://mcp.tilwhen.com/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "com-tilwhen-tilwhen": {
      "type": "remote",
      "url": "https://mcp.tilwhen.com/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add com-tilwhen-tilwhen --url https://mcp.tilwhen.com/mcp --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  com-tilwhen-tilwhen:
    url: "https://mcp.tilwhen.com/mcp"
```

### Other

```json
{
  "mcpServers": {
    "com-tilwhen-tilwhen": {
      "type": "http",
      "url": "https://mcp.tilwhen.com/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-08-02 (score 76, +1)

No change was recorded against any check on this day. Stability & Change Management went from 20 to 23. That category is still filling its 30-day observation window: 6 days of observed history at the previous scan, 7 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-31 (score 75, +3)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-30 (score 72, +1)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-29 (score 71, +1)

No change was recorded against any check on this day. Stability & Change Management went from 7 to 10. That category is still filling its 30-day observation window: 2 days of observed history at the previous scan, 3 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-27 (score 70, +1)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-26 (score 69)

First indexed and scored.

## MCP tools (9)

### `parse_date_query` (~108 tokens)

Parse a natural-language date question

Parses queries like "90 business days from today in uganda" into a normalized operation, answers it, and returns the auditable receipt. Ambiguous dates (03/04/2027) return needsClarification instead of a guess.

Input parameters:

- `locale` (string): Resolves ambiguous slash dates; omit to receive clarification choices
- `q` (string, required)
- `tz` (string): IANA timezone that defines "today" (e.g. Africa/Kampala). Default UTC.

Output parameters:

- `answer` (object): The calculated answer, absent when parsed is null
- `canonicalUrl` (string|null): tilwhen page that answers this query, to cite; null when no page covers it
- `confidence` (number): 1.0 is a clean grammar hit; below 0.5 the query is refused rather than guessed
- `needsClarification` (object): Present when the query is genuinely ambiguous (e.g. 03/04/2027); offers explicit choices instead of a guess
- `parsed`: Normalized operation, or null when the query could not be understood confidently
- `receipt` (object): Auditable receipt, absent when parsed is null
- `warnings` (array): Machine-readable notes, e.g. unsupported_unit or time_ignored

### `add_days` (~83 tokens)

Add calendar days to a date

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

Input parameters:

- `date` (string): ISO date YYYY-MM-DD, or "today" (resolved in tz)
- `days` (integer, required)
- `tz` (string): IANA timezone that defines "today" (e.g. Africa/Kampala). Default UTC.

Output parameters:

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

### `subtract_days` (~72 tokens)

Subtract calendar days from a date

The date N whole calendar days before a date.

Input parameters:

- `date` (string): ISO date YYYY-MM-DD, or "today" (resolved in tz)
- `days` (integer, required)
- `tz` (string): IANA timezone that defines "today" (e.g. Africa/Kampala). Default UTC.

Output parameters:

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

### `days_between` (~80 tokens)

Days between two dates

Signed whole calendar days from one date to another, midnight to midnight, endpoints exclusive (the gap).

Input parameters:

- `from` (string, required): ISO date YYYY-MM-DD, or "today" (resolved in tz)
- `to` (required)
- `tz` (string): IANA timezone that defines "today" (e.g. Africa/Kampala). Default UTC.

Output parameters:

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

### `business_days` (~241 tokens)

Business-day calculations

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 parameters:

- `customHolidays` (array): Custom organizational holiday calendar as ISO dates (mutually exclusive with jurisdiction)
- `date`: ISO date YYYY-MM-DD, or "today" (resolved in tz)
- `days` (integer)
- `from` (string): ISO date YYYY-MM-DD, or "today" (resolved in tz)
- `jurisdiction` (string): 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.
- `to`: ISO date YYYY-MM-DD, or "today" (resolved in tz)
- `tz` (string): IANA timezone that defines "today" (e.g. Africa/Kampala). Default UTC.
- `workweek` (string): Working week. Default mon-fri (Sat+Sun weekend).

Output parameters:

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

### `invoice_due` (~193 tokens)

Invoice due date from net terms

Due date for Net-N payment terms (calendar days, invoice date = day 0). Optional roll-forward past weekends and, with a jurisdiction or custom calendar, public holidays.

Input parameters:

- `customHolidays` (array): Custom organizational holiday calendar as ISO dates (mutually exclusive with jurisdiction)
- `invoiceDate` (string): ISO date YYYY-MM-DD, or "today" (resolved in tz)
- `jurisdiction` (string): 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.
- `net` (integer, required)
- `roll` (boolean)
- `tz` (string): IANA timezone that defines "today" (e.g. Africa/Kampala). Default UTC.
- `workweek` (string): Working week. Default mon-fri (Sat+Sun weekend).

Output parameters:

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

### `next_occurrence` (~117 tokens)

Next occurrence of an event or weekday

The next occurrence strictly after the base date (default today) of either a tracked event slug (e.g. "christmas") or a weekday (0 = Sunday .. 6 = Saturday). Provide exactly one of event/weekday.

Input parameters:

- `event` (string)
- `from` (string): ISO date YYYY-MM-DD, or "today" (resolved in tz)
- `tz` (string): IANA timezone that defines "today" (e.g. Africa/Kampala). Default UTC.
- `weekday` (integer)

Output parameters:

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

### `holidays` (~90 tokens)

Public holidays for a jurisdiction and year

Observed public holidays with the nominal (legal) date and status: rule (statutory) or declared (officially declared for that year). Declared-only holidays are omitted for undeclared years, with a holiday_data_incomplete warning.

Input parameters:

- `jurisdiction` (string, required): US, GB, GB-SCT, GB-NIR, CA, AU, UG (alias UK)
- `year` (integer, required)

Output parameters:

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

### `explain` (~278 tokens)

Explain a calculation step by step

Runs any operation and returns the receipt plus human-readable derivation steps. Accepts the same fields as the other tools, discriminated by op.

Input parameters:

- `customHolidays` (array): Custom organizational holiday calendar as ISO dates (mutually exclusive with jurisdiction)
- `date` (string): ISO date YYYY-MM-DD, or "today" (resolved in tz)
- `days` (integer)
- `event` (string)
- `from`: ISO date YYYY-MM-DD, or "today" (resolved in tz)
- `invoiceDate`: ISO date YYYY-MM-DD, or "today" (resolved in tz)
- `jurisdiction` (string): 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.
- `net` (integer)
- `op` (string, required)
- `roll` (boolean)
- `to`: ISO date YYYY-MM-DD, or "today" (resolved in tz)
- `tz` (string): IANA timezone that defines "today" (e.g. Africa/Kampala). Default UTC.
- `weekday` (integer)
- `workweek` (string): Working week. Default mon-fri (Sat+Sun weekend).
- `year` (integer)

Output parameters:

- `receipt` (object): Auditable receipt for the operation
- `steps` (array): Human-readable derivation, identical to the REST /api/v1/explain output

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/com-tilwhen-tilwhen/mcp#diagnostics

## Score history

- 2026-08-03: 76
- 2026-08-02: 76
- 2026-08-01: 75
- 2026-07-31: 75
- 2026-07-30: 72
- 2026-07-29: 71
- 2026-07-28: 70
- 2026-07-27: 70
- 2026-07-26: 69

## Links

- Remote endpoint: https://mcp.tilwhen.com/mcp
- Repository: https://github.com/abmwine/tilwhen
- Website: https://tilwhen.com/mcp
- Changelog RSS feed: https://verifymcp.io/servers/com-tilwhen-tilwhen/mcp/changelog.xml
- Changelog JSON feed: https://verifymcp.io/servers/com-tilwhen-tilwhen/mcp/changelog.json
- HTML version of this page: https://verifymcp.io/servers/com-tilwhen-tilwhen/mcp