Date & Time

ICS Calendar Recurrence Rule Expander

Expand RRULE-based VEVENT recurrence into concrete occurrences and export them as JSON or a flattened ICS calendar

json· JSON resultOpen tool

Quick start

Call this tool from your code in three languages.

cURL

# 1) Upload each file first → returns { filePath }
curl -X POST 'https://api.elysiatools.com/upload/ics-calendar-recurrence-rule-expander' \
  -F 'file=@/path/to/icsFile.ext'

# 2) Call the tool with the returned filePath values
curl -X POST 'https://api.elysiatools.com/en/api/tools/ics-calendar-recurrence-rule-expander' \
  -F 'icsInput=BEGIN:VEVENT
DTSTART:20260401T090000Z
DTEND:20260401T100000Z
RRULE:FREQ=WEEKLY;BYDAY=MO,WE;COUNT=6
SUMMARY:Team sync
UID:team-sync-1
END:VEVENT' \
  -F 'icsFile=/path/to/file.ext' \
  -F 'timezoneOverride=Asia/Shanghai' \
  -F 'holidayDates=2026-04-08' \
  -F 'maxOccurrences=20' \
  -F 'outputFormat=both'

API reference

Send a POST request with your inputs as JSON. File parameters require a separate upload first.

Endpoint

HTTP

POST https://api.elysiatools.com/en/api/tools/ics-calendar-recurrence-rule-expander

Parameters

Name	Type	Required	Description
icsInput	textarea	No	—
icsFile	fileupload required	No	—
timezoneOverride	text	No	—
holidayDates	textarea	No	—
maxOccurrences	number	No	—
outputFormat	select	No	—

File-type parameters must be uploaded first via POST /upload/ics-calendar-recurrence-rule-expander, then the returned filePath is passed to the corresponding file field.

Response format

JSON result

JSON

{
  "key": {...},
  "metadata": {
    "key": "value"
  },
  "error": "Error message (optional)",
  "message": "Notification message (optional)"
}

MCP integration

Add this tool to your Model Context Protocol server so AI agents can list and call it.

Server configuration

Add this block to your MCP client configuration:

mcp.json

{
  "mcpServers": {
    "elysiatools-ics-calendar-recurrence-rule-expander": {
      "name": "ics-calendar-recurrence-rule-expander",
      "description": "Expand RRULE-based VEVENT recurrence into concrete occurrences and export them as JSON or a flattened ICS calendar",
      "baseUrl": "https://api.elysiatools.com/mcp/sse?toolId=ics-calendar-recurrence-rule-expander",
      "command": "",
      "args": [],
      "env": {},
      "isActive": true,
      "type": "sse"
    }
  }
}

List available tools

After connecting to the SSE endpoint, list the exposed tools:

tools/list

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/list"
}

Call this tool

Invoke the tool by its id, passing arguments built from its parameters:

tools/call

{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "tools/call",
  "params": {
    "name": "ics-calendar-recurrence-rule-expander",
    "arguments": {
  "icsInput": "BEGIN:VEVENT\nDTSTART:20260401T090000Z\nDTEND:20260401T100000Z\nRRULE:FREQ=WEEKLY;BYDAY=MO,WE;COUNT=6\nSUMMARY:Team sync\nUID:team-sync-1\nEND:VEVENT",
  "icsFile": "https://example.com/file.ext",
  "timezoneOverride": "Asia/Shanghai",
  "holidayDates": "2026-04-08",
  "maxOccurrences": 20,
  "outputFormat": "both"
}
  }
}

Chain multiple tools in one session with a comma-separated toolId list, e.g. /mcp/sse?toolId=png-to-webp,jpg-to-webp,gif-to-webp (max 20).

File parameters accept a public file URL only (https://…). Local paths, data: URIs, and Base64 strings are not supported.

Questions or issues? Contact [email protected]