🚀 Free Lesson: Build a Fully Functional Calendar App with Just One Claude Skill and a JSON File

Learn how to turn plain natural language into a smart, self-updating calendar system — no coding, no setup, just pure structure and intelligence.

Just as I mentioned in the previous lesson — all you need to do is upload the SKILL.md file I’ve provided, and learn how to download the calendar.json file each time you start a new chat window in Claude.

You start first by saying “create a new calendar”.

And it would initiate a new calendar.json file.

I added all the public school holidays, early release dates for 2 years in one sentence.

It works instantly — no more missed school days or forgotten early pick-up times for my kids!

You can even add your yoga classes, school schedules, favorite restaurants, or every restaurant in a given ZIP code — including their lunch specials — all using simple natural language, as long as the information is public.

Give it a try!

SKILL.md

---

name: personal-schedule-manager
description: >
  Create, review, and edit a `calendar.json` file for schedules and routines.
  Summarizes upcoming events, detects conflicts, supports recurring rules,
  and runs natural-language multi-turn edits. Outputs a friendly summary and,
  when requested or on create, the complete `calendar.json` to copy/replace.
  Trigger phrase: “create a new personal calendar” (maps to intent=create with presets).

---
# ───────────────────────────────
# Inputs
# ───────────────────────────────
inputs:
  - id: intent
    type: string
    required: true
    description: One of: create | review | edit | export

  - id: calendar_json
    type: json
    required: false
    description: Paste full current `calendar.json` (omit for intent=create)

  - id: instructions
    type: string
    required: false
    description: Natural-language instructions (add/move/delete/recur/show conflicts/next 7 days)

  - id: date_range
    type: string
    required: false
    description: Optional range like “next 7 days”, “this month”, “2025-11-01..2025-11-30”

# ───────────────────────────────
# Outputs
# ───────────────────────────────
outputs:
  - id: human_summary
    type: markdown
    description: Clear summary of actions taken, upcoming events, and any conflicts.

  - id: calendar_json
    type: json
    description: Full updated file (on create/export, or when explicitly requested)

# ───────────────────────────────
# Behavior
# ───────────────────────────────
# • Default timezone: America/New_York (can be overridden via file or instruction)
# • Good initial defaults (优选初始值):
#   - defaults.event_duration_minutes = 60
#   - defaults.reminder_minutes_before = 30
#   - defaults.work_hours = 09:00–17:00, MO–FR
#   - defaults.priority = “normal”
#   - defaults.category = “personal”
# • Recurrence: iCalendar RRULE (e.g., FREQ=WEEKLY;BYDAY=WE;UNTIL=20251218)
# • Conflict detection: overlapping active events in the same timezone
# • Destructive edits: show a diff; apply only after user says “apply changes”
# • Natural-language verbs: add | move | reschedule | delete | skip (occurrence) | duplicate | tag | remind
# • On intent=create:
#     - Emit a fresh, canonical `calendar.json` with New York time + presets (see schema below)
# • Export: echoes the full canonical JSON

# ───────────────────────────────
# Schema (informative)
# ───────────────────────────────
# Top-level:
# {
#   “version”: “1.1”,
#   “timezone”: “America/New_York”,
#   “defaults”: {
#     “event_duration_minutes”: 60,
#     “reminder_minutes_before”: 30,
#     “work_hours”: {”start”: “09:00”, “end”: “17:00”, “days”: [”MO”,”TU”,”WE”,”TH”,”FR”]},
#     “priority”: “normal”,      # default priority for new events
#     “category”: “personal”     # default category for new events
#   },
#   “categories”: [”personal”,”family”,”work”,”school”,”health”,”finance”,”errands”,”travel”,”learning”],
#   “priority_levels”: [”critical”,”high”,”normal”,”low”],
#   “events”: [ Event ],
#   “exceptions”: [ Exception ],
#   “attendees”: [ Attendee ],
#   “audit”: [ AuditEntry ]
# }
#
# Event:
# {
#   “id”: “evt_001”,
#   “title”: “Deep Work”,
#   “start”: “2025-11-03T09:00:00”,
#   “end”: “2025-11-03T10:30:00”,
#   “timezone”: “America/New_York”,
#   “location”: “Home Office”,
#   “notes”: “No meetings.”,
#   “tags”: [”focus”],
#   “category”: “work”,          # NEW: one of categories (or a custom string)
#   “priority”: “high”,          # NEW: one of priority_levels
#   “recurrence”: null,          # RRULE string or null
#   “reminders”: [15],           # minutes before start
#   “status”: “confirmed”,       # tentative | confirmed | cancelled
#   “created_at”: “UTC-ISO”,     # e.g., 2025-10-30T20:00:00Z
#   “updated_at”: “UTC-ISO”
# }