Kalender Sync

Create event

create_event

Creates an event in one of the calendars this access may write to.

Availability in the requested slot is checked LIVE (not from cache). An overlapping event does NOT prevent creation — the event is created regardless and the overlap comes back as a warning. Pass that warning on to the user instead of silently double-booking; whether the overlap is intended is the user's call.

The check counts only events that BLOCK the time (blocks_time: true in get_availability). Entries that do not block it — holidays, birthdays, and every all-day event from Apple/iCloud — are deliberately not reported as conflicts, because otherwise every booking on a day carrying a holiday would look like a clash. So no warning does NOT mean the day is empty: an all-day "Baustelle Darmstadt" is a working day that will not show up here. When the user asks to book on a specific day, check the day with get_availability first and mention what is already on it.

All-day events: pass bare dates (start: "2026-09-01", end: "2026-09-03") or set all_day: true. For all-day the end date is INCLUSIVE — that example creates a three-day event covering 1–3 September. Both ends must use the same form.

calendar_id is only needed when several calendars are writable; with exactly one, that one is used. list_calendars shows the writable calendars. title is required.

Check status first: credits_exhausted means this call was NOT performed. Only warnings and credit information are returned in that case; no result data or write confirmation. Tell the user how to restore credits; do not retry automatically.

Input Schema

TableJSON Schema

Name	Required	Description
`end`	Yes	End — same form as `start`. For all-day events this date is INCLUSIVE (end 2026-09-03 means the event runs through 3 September).
`start`	Yes	Start — either an ISO 8601 timestamp WITH timezone (2026-07-28T10:00:00+02:00 or …Z), or a bare date (2026-07-28) for an all-day event. A timestamp without a zone is rejected.
`title`	Yes	Event title (required)
`all_day`	No	Force an all-day event; time components in start/end are then discarded. Not needed when start/end are already bare dates.
`location`	No
`time_zone`	No	IANA zone, e.g. America/New_York. For timed events it preserves the NAMED zone so the event follows daylight saving (without it the event is stored as UTC and shows as GMT in Apple Calendar, and a recurring series will not shift with the clocks). For all-day events it decides which local day is covered. Always send it when you know the user's zone; defaults to UTC.
`calendar_id`	No	Target calendar; only needed when several are writable
`description`	No

Output Schema

TableJSON Schema

Name	Required	Description
`status`	Yes	ok: tool executed; use its result fields. credits_exhausted: not executed; no result fields.
`warning`	No
`event_id`	No
`warnings`	No
`resets_at`	No
`calendar_id`	No
`calendar_name`	No
`credits_required`	No
`credits_available`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedOct 18, 2026
- addedInput schema / properties / description / maxLength
```
Added value: +8000
```
- addedInput schema / properties / location / maxLength
```
Added value: +1000
```
- addedInput schema / properties / title / maxLength
```
Added value: +500
```

Changed6 schema fields changedOct 11, 2026

addedOutput schema / properties / credits_available
```
Added value: +{
+  "type": "number"
+}
```
addedOutput schema / properties / credits_required
```
Added value: +{
+  "type": "number"
+}
```

addedOutput schema / properties / resets_at

Added value: +{
+  "type": [
+    "string",
+    "null"
+  ]
+}

addedOutput schema / properties / status

Added value: +{
+  "description": "ok: tool executed; use its result fields. credits_exhausted: not executed; no result fields.",
+  "enum": [
+    "ok",
+    "credits_exhausted"
+  ],
+  "type": "string"
+}

addedOutput schema / properties / warnings

Added value: +{
+  "items": {
+    "type": "string"
+  },
+  "type": "array"
+}

changedOutput schema / required

Previous value: -[
-  "event_id",
-  "calendar_id"
-]New value: +[
+  "status"
+]

Changed1 schema field changedAug 28, 2026

changedInput schema / properties / time_zone / description

Previous value: -"IANA zone (e.g. Europe/Brussels) deciding which local day an all-day event covers. Defaults to UTC. Ignored for timed events, which carry their own offset."New value: +"IANA zone, e.g. America/New_York. For timed events it preserves the NAMED zone so the event follows daylight saving (without it the event is stored as UTC and shows as GMT in Apple Calendar, and a recurring series will not shift with the clocks). For all-day events it decides which local day is covered. Always send it when you know the user's zone; defaults to UTC."

Changed4 schema fields changedAug 27, 2026

addedInput schema / properties / all_day

Added value: +{
+  "description": "Force an all-day event; time components in start/end are then discarded. Not needed when start/end are already bare dates.",
+  "type": "boolean"
+}

changedInput schema / properties / end / description

Previous value: -"End, ISO 8601 with timezone"New value: +"End — same form as `start`. For all-day events this date is INCLUSIVE (end 2026-09-03 means the event runs through 3 September)."

changedInput schema / properties / start / description

Previous value: -"Start, ISO 8601 WITH timezone — e.g. 2026-07-28T10:00:00+02:00 or …Z. Rejected without a zone."New value: +"Start — either an ISO 8601 timestamp WITH timezone (2026-07-28T10:00:00+02:00 or …Z), or a bare date (2026-07-28) for an all-day event. A timestamp without a zone is rejected."

addedInput schema / properties / time_zone

Added value: +{
+  "description": "IANA zone (e.g. Europe/Brussels) deciding which local day an all-day event covers. Defaults to UTC. Ignored for timed events, which carry their own offset.",
+  "type": "string"
+}

First observedJul 31, 2026

TDQS

A4.8/5.0

Behavior5/5

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

Goes well past the annotations (readOnlyHint=false, destructiveHint=false): it discloses that availability is checked LIVE, that overlaps do NOT block creation and instead return a warning the agent must surface, that only blocks_time:true entries count as conflicts, and that credits_exhausted means the call was not performed and no write confirmation exists. That is exactly the kind of consequence-level detail annotations cannot carry.

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

Conciseness4/5

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

Front-loaded with purpose, then behavior, then parameters, then the status contract — a sensible ordering. It is long, and the all-day inclusive-end rule is restated from the schema, but for a tool with this many sharp edges most sentences carry operational weight.

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?

For an 8-parameter write tool with a sibling list of 14, the description covers the failure mode (credits_exhausted), the conflict semantics, timezone/all-day handling, and calendar selection. An output schema exists, so it correctly does not spend space on return shape beyond the status/warning contract.

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 coverage is 75%, and the description fills the important gaps: all-day end is INCLUSIVE with a concrete 1–3 September example, both ends must use the same form, calendar_id is conditionally optional, and title is required. It does not address location or description (the undescribed schema fields), but those are self-evident string fields.

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?

Opens with a specific verb+resource ('Creates an event') plus a scope constraint ('in one of the calendars this access may write to') that immediately separates it from update_event and delete_event. An agent knows what this does and where it lands without opening the schema.

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

Usage Guidelines5/5

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

Explicitly routes the agent: 'check the day with get_availability first' when a user asks to book a specific day, 'list_calendars shows the writable calendars', and calendar_id is only needed when several calendars are writable. It also gives a when-not-to-act rule (credits_exhausted → do not retry automatically).

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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