---
name: calendar_meeting_series_rungs
description: "Set up a recurring weekly meeting on specific days with a set number of occurrences and a pop-up reminder a certain number of minutes before it starts. calendar_meeting_series_rungs: An iCalendar file (RFC 5545): one VCALENDAR with VERSION:2.0 and exactly the given PRODID, containing exactly one VEV"
---

# calendar_meeting_series_rungs (a Neruva verified skill for `calendar`)

Set up a recurring weekly meeting on specific days with a set number of occurrences and a pop-up reminder a certain number of minutes before it starts.

Verified helper code for `calendar`, python. Entry points: `parse_utc_stamp`, `create_vevent`, `create_calendar`, `serialize_calendar`, `write_ics`.
Code hash sha256 `49e3cb7a727c6c0cc007fc90c45c885d8dc85c0933cc820d75142fa0e170d813`, signed (ed25519). Banked by `legacy-dev`.

## One call

Call `build(**args)` with an object matching this schema. You do not have to write code or match the helper signatures below.

```json
{
  "type": "object",
  "properties": {
    "output_path": {
      "type": "string",
      "description": "Filesystem path where the .ics file will be written. Parent directories will be created if they do not exist."
    },
    "uid": {
      "type": "string",
      "description": "Unique identifier for the VEVENT (UID field)."
    },
    "summary": {
      "type": "string",
      "description": "Event title/summary text (SUMMARY field), also used as the VALARM description."
    },
    "location": {
      "type": "string",
      "description": "Event location text (LOCATION field)."
    },
    "dtstart": {
      "type": "string",
      "description": "Event start time as a UTC timestamp string ending in 'Z', format %Y%m%dT%H%M%SZ, e.g. '20250503T060000Z'."
    },
    "dtend": {
      "type": "string",
      "description": "Event end time as a UTC timestamp string ending in 'Z', format %Y%m%dT%H%M%SZ, e.g. '20250503T063000Z'."
    },
    "byday": {
      "type": "array",
      "items": {
        "type": "string"
      },
      "description": "List of two-letter weekday codes for the RRULE BYDAY, e.g. ['MO', 'SA', 'FR']."
    },
    "count": {
      "type": "integer",
      "description": "Number of occurrences for the RRULE COUNT value."
    },
    "alarm_minutes": {
      "type": "integer",
      "description": "Number of minutes before DTSTART that the VALARM TRIGGER fires (given as a positive integer; will be applied as a negative duration)."
    },
    "prodid": {
      "type": "string",
      "description": "PRODID value for the VCALENDAR, e.g. '-//Stark//Cal//EN'."
    }
  },
  "required": [
    "output_path",
    "uid",
    "summary",
    "location",
    "dtstart",
    "dtend",
    "byday",
    "count",
    "alarm_minutes",
    "prodid"
  ]
}
```

Example arguments:

```json
{
  "output_path": "/tmp/calendars/retro_series.ics",
  "uid": "call-0139@stark.example",
  "summary": "Retro",
  "location": "Room 5",
  "dtstart": "20250503T060000Z",
  "dtend": "20250503T063000Z",
  "byday": [
    "MO",
    "SA",
    "FR"
  ],
  "count": 15,
  "alarm_minutes": 30,
  "prodid": "-//Stark//Cal//EN"
}
```

```python
def build(**kwargs):
    output_path = kwargs["output_path"]
    uid = kwargs["uid"]
    summary = kwargs["summary"]
    location = kwargs["location"]
    dtstart = kwargs["dtstart"]
    dtend = kwargs["dtend"]
    byday = kwargs["byday"]
    count = kwargs["count"]
    alarm_minutes = kwargs["alarm_minutes"]
    prodid = kwargs["prodid"]

    event = create_vevent(uid, summary, location, dtstart, dtend, byday, count, alarm_minutes)
    cal = create_calendar(prodid, event)
    data_bytes = serialize_calendar(cal)

    parent_dir = os.path.dirname(output_path)
    if parent_dir:
        os.makedirs(parent_dir, exist_ok=True)

    write_ics(output_path, data_bytes)
    return output_path
```

## How to use it

Helper functions for building an RFC 5545 iCalendar file with one VEVENT,
an RRULE, and one VALARM, using CRLF line endings.

1. parse_utc_stamp(dtstr)
   - Parameters: dtstr (str) - a UTC timestamp string ending in 'Z',
     e.g. "20250503T060000Z"
   - Returns: an aware datetime.datetime in UTC
   - Example: parse_utc_stamp("20250503T060000Z")

2. create_vevent(uid, summary, location, dtstart, dtend, byday, count, alarm_minutes)
   - Parameters:
       uid (str), summary (str), location (str)
       dtstart (str), dtend (str): UTC timestamp strings ending in 'Z'
       byday (list[str]): weekday codes like ["MO", "SA", "FR"]
       count (int): RRULE COUNT
       alarm_minutes (int): minutes before dtstart the VALARM triggers
   - Returns: icalendar.Event populated with DTSTART, DTEND, SUMMARY,
     LOCATION, UID, RRULE (FREQ=WEEKLY;BYDAY=...;COUNT=...), and a VALARM
     child component with ACTION:DISPLAY and a negative-duration TRIGGER.
   - Example:
       create_vevent("call-0139@stark.example", "Retro", "Room 5",
                     "20250503T060000Z", "20250503T063000Z",
                     ["MO", "SA", "FR"], 15, 30)

3. create_calendar(prodid, events)
   - Parameters:
       prodid (str): PRODID value
       events: a single icalendar.Event or a list of them
   - Returns: icalendar.Calendar with VERSION:2.0, the given PRODID, and
     the given VEVENT(s) added.
   - Example: create_calendar("-//Stark//Cal//EN", event)

4. serialize_calendar(cal)
   - Parameters: cal (icalendar.Calendar)
   - Returns: bytes of the serialized calendar with CRLF line endings
   - Example: serialize_calendar(cal)

5. write_ics(path, data_bytes)
   - Parameters: path (str) output file path, data_bytes (bytes) content
   - Returns: None (writes file to disk in binary mode)
   - Example: write_ics("/tmp/out.ics", data_bytes)


## Evidence (corpus named)

- held-out 16 specs, best-of-2, deepseek-chat: cold 0.375 -> 0.875 with the rung (CI +0.250..+0.750); helper reuse 1.00
- checker forged and mutation-gated, not hand-written: references accepted, every spoiler rejected, empty rejected, on 2 given specs plus 6 generated ($0.13)
- stage-1 gate before forging: 2/8 for the cheap tier cold, so the gate opened

## Files

- `scripts/skill.py`: the verified code (GET /v1/commons/rungs/rec_2e2daa08322849fba91a24b7fccf560c/code)
- verify: POST /v1/commons/verify {"id": "rec_2e2daa08322849fba91a24b7fccf560c"}