CalDAV MCP Server

Create calendar event

create_event

Create a new event in a writable iCloud calendar by specifying calendar ID, start, end, and title; optionally add location, notes, alarms, or recurrence. Returns the stored event without modifying existing ones.

Instructions

Create a new event in a writable iCloud calendar and return the stored representation; existing events are not changed. Use list_calendars first to obtain calendar_id, and use update_event when the event already exists. Timed values require matching offsets and timezones, all-day end dates are exclusive, and recurrence rules omit the RRULE: prefix.

Input Schema

TableJSON Schema

Name	Required	Description
`end`	Yes	Event end using the same temporal type and timezone as start; an all-day end date is exclusive.
`rrule`	No	RFC 5545 recurrence rule without the RRULE: prefix; defaults to null.
`start`	Yes	Event start as a timed date-time or all-day date.
`alarms`	No	Display reminders; defaults to an empty array.
`summary`	Yes	Event title, between 1 and 1,024 characters.
`location`	No	Event location; defaults to null.
`calendar_id`	Yes	Opaque destination calendar ID returned by list_calendars.
`description`	No	Event notes; defaults to null.

Output Schema

TableJSON Schema

Name	Required	Description
`end`	Yes	Normalized event end.
`uid`	Yes	Stored iCalendar UID.
`etag`	Yes	Current ETag for optimistic concurrency, when available.
`href`	Yes	Redacted fingerprint of the CalDAV resource URL.
`rrule`	Yes	Stored RFC 5545 recurrence rule without the RRULE: prefix.
`start`	Yes	Normalized event start.
`alarms`	Yes	Normalized alarms attached to the event.
`summary`	Yes	Stored event title.
`location`	Yes	Stored event location.
`raw_ical`	No	Raw iCalendar resource, included only when explicitly requested.
`recurring`	Yes	Whether this event belongs to a recurring series.
`calendar_id`	Yes	Opaque ID of the containing calendar.
`description`	Yes	Stored event notes.
`resource_id`	Yes	Opaque event ID accepted by get_event, update_event, and delete_event.
`recurrence_id`	Yes	Occurrence identifier for an expanded recurring event.
`recurrence_exception`	Yes	Whether this result is an overridden recurrence instance.

Schema Changelog

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

Changed14 schema fields changedv0.1.7Sep 5, 2026

removedOutput schema / properties / alarms / items / properties / description / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

addedOutput schema / properties / alarms / items / properties / description / type
```
Added value: +[
+  "string",
+  "null"
+]
```

removedOutput schema / properties / alarms / items / properties / uid / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

addedOutput schema / properties / alarms / items / properties / uid / type
```
Added value: +[
+  "string",
+  "null"
+]
```

removedOutput schema / properties / description / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

addedOutput schema / properties / description / type
```
Added value: +[
+  "string",
+  "null"
+]
```

removedOutput schema / properties / etag / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

addedOutput schema / properties / etag / type
```
Added value: +[
+  "string",
+  "null"
+]
```

removedOutput schema / properties / location / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

addedOutput schema / properties / location / type
```
Added value: +[
+  "string",
+  "null"
+]
```

removedOutput schema / properties / recurrence_id / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

addedOutput schema / properties / recurrence_id / type
```
Added value: +[
+  "string",
+  "null"
+]
```

removedOutput schema / properties / rrule / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

addedOutput schema / properties / rrule / type
```
Added value: +[
+  "string",
+  "null"
+]
```

Changed37 schema fields changedv0.1.1Sep 4, 2026

addedInput schema / properties / alarms / description

Added value: +"Display reminders; defaults to an empty array."

addedInput schema / properties / alarms / items / description
```
Added value: +"A display reminder attached to an event."
```
addedInput schema / properties / alarms / items / properties / action / description
```
Added value: +"Alarm action; only DISPLAY is supported."
```
addedInput schema / properties / alarms / items / properties / description / description
```
Added value: +"Optional notification text for this alarm."
```
addedInput schema / properties / alarms / items / properties / minutes_before / description
```
Added value: +"Whole minutes before the event start; use 0 for an alarm at start time."
```

addedInput schema / properties / calendar_id / description

Added value: +"Opaque destination calendar ID returned by list_calendars."

addedInput schema / properties / description / description
```
Added value: +"Event notes; defaults to null."
```

changedInput schema / properties / end / anyOf

Previous value: -[
-  {
-    "additionalProperties": false,
-    "properties": {
-      "date_time": {
-        "pattern": "^\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}(?:Z|[+-]\\d{2}:\\d{2})$",
-        "type": "string"
-      },
-      "timezone": {
-        "type": "string"
-      }
-    },
-    "required": [
-      "date_time",
-      "timezone"
-    ],
-    "type": "object"
-  },
-  {
-    "additionalProperties": false,
-    "properties": {
-      "date": {
-        "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
-        "type": "string"
-      }
-    },
-    "required": [
-      "date"
-    ],
-    "type": "object"
-  }
-]New value: +[
+  {
+    "additionalProperties": false,
+    "description": "A timed calendar value with an explicit offset and IANA timezone.",
+    "properties": {
+      "date_time": {
+        "description": "ISO 8601 date-time with seconds and an explicit UTC offset or Z.",
+        "pattern": "^\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}(?:Z|[+-]\\d{2}:\\d{2})$",
+        "type": "string"
+      },
+      "timezone": {
+        "description": "IANA timezone for the local event time; its offset must match date_time.",
+        "type": "string"
+      }
+    },
+    "required": [
+      "date_time",
+      "timezone"
+    ],
+    "type": "object"
+  },
+  {
+    "additionalProperties": false,
+    "description": "An all-day calendar value.",
+    "properties": {
+      "date": {
+        "description": "Calendar date in YYYY-MM-DD format.",
+        "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
+        "type": "string"
+      }
+    },
+    "required": [
+      "date"
+    ],
+    "type": "object"
+  }
+]

addedInput schema / properties / end / description

Added value: +"Event end using the same temporal type and timezone as start; an all-day end date is exclusive."

addedInput schema / properties / location / description
```
Added value: +"Event location; defaults to null."
```

addedInput schema / properties / rrule / description

Added value: +"RFC 5545 recurrence rule without the RRULE: prefix; defaults to null."

changedInput schema / properties / start / anyOf

Previous value: -[
-  {
-    "additionalProperties": false,
-    "properties": {
-      "date_time": {
-        "pattern": "^\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}(?:Z|[+-]\\d{2}:\\d{2})$",
-        "type": "string"
-      },
-      "timezone": {
-        "type": "string"
-      }
-    },
-    "required": [
-      "date_time",
-      "timezone"
-    ],
-    "type": "object"
-  },
-  {
-    "additionalProperties": false,
-    "properties": {
-      "date": {
-        "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
-        "type": "string"
-      }
-    },
-    "required": [
-      "date"
-    ],
-    "type": "object"
-  }
-]New value: +[
+  {
+    "additionalProperties": false,
+    "description": "A timed calendar value with an explicit offset and IANA timezone.",
+    "properties": {
+      "date_time": {
+        "description": "ISO 8601 date-time with seconds and an explicit UTC offset or Z.",
+        "pattern": "^\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}(?:Z|[+-]\\d{2}:\\d{2})$",
+        "type": "string"
+      },
+      "timezone": {
+        "description": "IANA timezone for the local event time; its offset must match date_time.",
+        "type": "string"
+      }
+    },
+    "required": [
+      "date_time",
+      "timezone"
+    ],
+    "type": "object"
+  },
+  {
+    "additionalProperties": false,
+    "description": "An all-day calendar value.",
+    "properties": {
+      "date": {
+        "description": "Calendar date in YYYY-MM-DD format.",
+        "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
+        "type": "string"
+      }
+    },
+    "required": [
+      "date"
+    ],
+    "type": "object"
+  }
+]

addedInput schema / properties / start / description

Added value: +"Event start as a timed date-time or all-day date."

addedInput schema / properties / summary / description

Added value: +"Event title, between 1 and 1,024 characters."

addedOutput schema / properties / alarms / description

Added value: +"Normalized alarms attached to the event."

addedOutput schema / properties / alarms / items / description

Added value: +"A normalized alarm returned by iCloud Calendar."

addedOutput schema / properties / alarms / items / properties / action / description
```
Added value: +"Stored iCalendar alarm action."
```
addedOutput schema / properties / alarms / items / properties / description / description
```
Added value: +"Stored alarm notification text, when available."
```
addedOutput schema / properties / alarms / items / properties / minutes_before / description
```
Added value: +"Whole minutes before event start, when representable."
```
addedOutput schema / properties / alarms / items / properties / uid / description
```
Added value: +"Stored alarm UID, when available."
```
addedOutput schema / properties / calendar_id / description
```
Added value: +"Opaque ID of the containing calendar."
```
addedOutput schema / properties / description / description
```
Added value: +"Stored event notes."
```

changedOutput schema / properties / end / anyOf

Previous value: -[
-  {
-    "additionalProperties": false,
-    "properties": {
-      "date_time": {
-        "pattern": "^\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}(?:Z|[+-]\\d{2}:\\d{2})$",
-        "type": "string"
-      },
-      "timezone": {
-        "maxLength": 4096,
-        "minLength": 1,
-        "type": "string"
-      }
-    },
-    "required": [
-      "date_time",
-      "timezone"
-    ],
-    "type": "object"
-  },
-  {
-    "additionalProperties": false,
-    "properties": {
-      "date": {
-        "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
-        "type": "string"
-      }
-    },
-    "required": [
-      "date"
-    ],
-    "type": "object"
-  }
-]New value: +[
+  {
+    "additionalProperties": false,
+    "description": "A stored timed calendar value.",
+    "properties": {
+      "date_time": {
+        "description": "Stored ISO 8601 date-time with seconds and an explicit UTC offset or Z.",
+        "pattern": "^\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}(?:Z|[+-]\\d{2}:\\d{2})$",
+        "type": "string"
+      },
+      "timezone": {
+        "description": "IANA timezone associated with the stored date-time.",
+        "maxLength": 4096,
+        "minLength": 1,
+        "type": "string"
+      }
+    },
+    "required": [
+      "date_time",
+      "timezone"
+    ],
+    "type": "object"
+  },
+  {
+    "additionalProperties": false,
+    "description": "An all-day calendar value.",
+    "properties": {
+      "date": {
+        "description": "Calendar date in YYYY-MM-DD format.",
+        "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
+        "type": "string"
+      }
+    },
+    "required": [
+      "date"
+    ],
+    "type": "object"
+  }
+]

addedOutput schema / properties / end / description
```
Added value: +"Normalized event end."
```

addedOutput schema / properties / etag / description

Added value: +"Current ETag for optimistic concurrency, when available."

addedOutput schema / properties / href / description

Added value: +"Redacted fingerprint of the CalDAV resource URL."

addedOutput schema / properties / location / description
```
Added value: +"Stored event location."
```

addedOutput schema / properties / raw_ical / description

Added value: +"Raw iCalendar resource, included only when explicitly requested."

addedOutput schema / properties / recurrence_exception / description

Added value: +"Whether this result is an overridden recurrence instance."

addedOutput schema / properties / recurrence_id / description

Added value: +"Occurrence identifier for an expanded recurring event."

addedOutput schema / properties / recurring / description

Added value: +"Whether this event belongs to a recurring series."

addedOutput schema / properties / resource_id / description

Added value: +"Opaque event ID accepted by get_event, update_event, and delete_event."

addedOutput schema / properties / rrule / description

Added value: +"Stored RFC 5545 recurrence rule without the RRULE: prefix."

changedOutput schema / properties / start / anyOf

Previous value: -[
-  {
-    "additionalProperties": false,
-    "properties": {
-      "date_time": {
-        "pattern": "^\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}(?:Z|[+-]\\d{2}:\\d{2})$",
-        "type": "string"
-      },
-      "timezone": {
-        "maxLength": 4096,
-        "minLength": 1,
-        "type": "string"
-      }
-    },
-    "required": [
-      "date_time",
-      "timezone"
-    ],
-    "type": "object"
-  },
-  {
-    "additionalProperties": false,
-    "properties": {
-      "date": {
-        "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
-        "type": "string"
-      }
-    },
-    "required": [
-      "date"
-    ],
-    "type": "object"
-  }
-]New value: +[
+  {
+    "additionalProperties": false,
+    "description": "A stored timed calendar value.",
+    "properties": {
+      "date_time": {
+        "description": "Stored ISO 8601 date-time with seconds and an explicit UTC offset or Z.",
+        "pattern": "^\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}(?:Z|[+-]\\d{2}:\\d{2})$",
+        "type": "string"
+      },
+      "timezone": {
+        "description": "IANA timezone associated with the stored date-time.",
+        "maxLength": 4096,
+        "minLength": 1,
+        "type": "string"
+      }
+    },
+    "required": [
+      "date_time",
+      "timezone"
+    ],
+    "type": "object"
+  },
+  {
+    "additionalProperties": false,
+    "description": "An all-day calendar value.",
+    "properties": {
+      "date": {
+        "description": "Calendar date in YYYY-MM-DD format.",
+        "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
+        "type": "string"
+      }
+    },
+    "required": [
+      "date"
+    ],
+    "type": "object"
+  }
+]

addedOutput schema / properties / start / description
```
Added value: +"Normalized event start."
```
addedOutput schema / properties / summary / description
```
Added value: +"Stored event title."
```
addedOutput schema / properties / uid / description
```
Added value: +"Stored iCalendar UID."
```

First observedv0.1.0Sep 4, 2026

TDQS

A4.7/5.0

Behavior5/5

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

Beyond annotations, the description adds meaningful behavioral context: it requires a writable calendar, returns the stored representation, guarantees existing events are unchanged, and warns about timezone offset matching, exclusive all-day end dates, and RRULE prefix omission. These constraints are not deducible from the annotations (readOnlyHint=false, destructiveHint=false).

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?

Three sentences with no filler. The core purpose is front-loaded, and each subsequent sentence adds distinct, high-value guidance: prerequisites, alternative tool, and tricky format constraints. Every sentence earns its place.

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 a complex create tool with 8 parameters, the description covers prerequisites, alternatives, return behavior, and the most error-prone input constraints. Since an output schema exists, it appropriately does not need to describe return structure further.

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

Parameters3/5

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

Schema description coverage is 100%, so the schema already documents all parameters in detail. The description reinforces key constraints like timezone matching, exclusive all-day ends, and RRULE prefix omission, but these largely restate what the schema properties already say, adding limited new meaning.

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 uses a specific verb and resource—'Create a new event in a writable iCloud calendar'—and explicitly contrasts with update_event by noting 'existing events are not changed.' This clearly differentiates the tool from its siblings like list_events and get_event.

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?

It gives explicit when-to-use guidance: 'Use list_calendars first to obtain calendar_id, and use update_event when the event already exists.' This directly routes an agent to prerequisites and alternatives, leaving no ambiguity about the tool's appropriate context.

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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