d0nghyun/api-google-calendar

Google Calendar Skill

When to Activate

• Query today's/weekly events
• Create meeting events
• Update or delete events
• Integrate with /weekly command

Authentication

Credentials File: .credentials/google.json

{
  "client_id": "...",
  "client_secret": "...",
  "refresh_token": "..."
}

Create credentials at: https://console.cloud.google.com/apis/credentials

Setup Steps:

1. Create OAuth2 credentials in Google Cloud Console
2. Enable Google Calendar API
3. Get refresh token via OAuth2 flow
4. Store in .credentials/google.json

Load credentials before API calls:

GOOGLE_CLIENT_ID=$(jq -r '.client_id' /Users/dhlee/Git/personal/neuron/.credentials/google.json)
GOOGLE_CLIENT_SECRET=$(jq -r '.client_secret' /Users/dhlee/Git/personal/neuron/.credentials/google.json)
GOOGLE_REFRESH_TOKEN=$(jq -r '.refresh_token' /Users/dhlee/Git/personal/neuron/.credentials/google.json)

API Base URL

https://www.googleapis.com/calendar/v3

Get Access Token

Refresh tokens to get short-lived access tokens:

ACCESS_TOKEN=$(curl -s -X POST "https://oauth2.googleapis.com/token" \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "client_id=$GOOGLE_CLIENT_ID" \
  -d "client_secret=$GOOGLE_CLIENT_SECRET" \
  -d "refresh_token=$GOOGLE_REFRESH_TOKEN" \
  -d "grant_type=refresh_token" | jq -r '.access_token')

Common Operations

List Events (Today)

TODAY=$(date +%Y-%m-%dT00:00:00Z)
TOMORROW=$(date -v+1d +%Y-%m-%dT00:00:00Z)

curl -s -H "Authorization: Bearer $ACCESS_TOKEN" \
  "https://www.googleapis.com/calendar/v3/calendars/${GOOGLE_CALENDAR_ID:-primary}/events?timeMin=$TODAY&timeMax=$TOMORROW&singleEvents=true&orderBy=startTime"

List Events (This Week)

TODAY=$(date +%Y-%m-%dT00:00:00Z)
WEEK_END=$(date -v+7d +%Y-%m-%dT23:59:59Z)

curl -s -H "Authorization: Bearer $ACCESS_TOKEN" \
  "https://www.googleapis.com/calendar/v3/calendars/${GOOGLE_CALENDAR_ID:-primary}/events?timeMin=$TODAY&timeMax=$WEEK_END&singleEvents=true&orderBy=startTime"

Create Event

curl -s -X POST \
  -H "Authorization: Bearer $ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "summary": "Meeting Title",
    "description": "Meeting description",
    "start": {
      "dateTime": "2026-01-20T14:00:00+09:00",
      "timeZone": "Asia/Seoul"
    },
    "end": {
      "dateTime": "2026-01-20T15:00:00+09:00",
      "timeZone": "Asia/Seoul"
    },
    "attendees": [
      {"email": "[email protected]"}
    ]
  }' \
  "https://www.googleapis.com/calendar/v3/calendars/${GOOGLE_CALENDAR_ID:-primary}/events"

Update Event

curl -s -X PATCH \
  -H "Authorization: Bearer $ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "summary": "Updated Title"
  }' \
  "https://www.googleapis.com/calendar/v3/calendars/${GOOGLE_CALENDAR_ID:-primary}/events/{eventId}"

Delete Event

curl -s -X DELETE \
  -H "Authorization: Bearer $ACCESS_TOKEN" \
  "https://www.googleapis.com/calendar/v3/calendars/${GOOGLE_CALENDAR_ID:-primary}/events/{eventId}"

Integration with /weekly

The /weekly command can query calendar events to auto-populate the weekly update:

# Load credentials
GOOGLE_CLIENT_ID=$(jq -r '.client_id' /Users/dhlee/Git/personal/neuron/.credentials/google.json)
GOOGLE_CLIENT_SECRET=$(jq -r '.client_secret' /Users/dhlee/Git/personal/neuron/.credentials/google.json)
GOOGLE_REFRESH_TOKEN=$(jq -r '.refresh_token' /Users/dhlee/Git/personal/neuron/.credentials/google.json)

# Get this week's meetings for /weekly
ACCESS_TOKEN=$(curl -s -X POST "https://oauth2.googleapis.com/token" \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "client_id=$GOOGLE_CLIENT_ID" \
  -d "client_secret=$GOOGLE_CLIENT_SECRET" \
  -d "refresh_token=$GOOGLE_REFRESH_TOKEN" \
  -d "grant_type=refresh_token" | jq -r '.access_token')

curl -s -H "Authorization: Bearer $ACCESS_TOKEN" \
  "https://www.googleapis.com/calendar/v3/calendars/primary/events?timeMin=$(date -v-7d +%Y-%m-%dT00:00:00Z)&timeMax=$(date +%Y-%m-%dT23:59:59Z)&singleEvents=true&orderBy=startTime" \
  | jq '.items[] | {summary, start: .start.dateTime, attendees: [.attendees[]?.email]}'

Error Handling

| Status | Meaning | Action | |--------|---------|--------| | 401 | Invalid/expired token | Refresh access token | | 403 | Insufficient permissions | Check OAuth2 scopes | | 404 | Calendar/event not found | Verify calendar ID | | 429 | Rate limit exceeded | Wait and retry |

OAuth2 Scopes Required

• https://www.googleapis.com/auth/calendar.readonly - Read events
• https://www.googleapis.com/auth/calendar.events - Create/update/delete events

References

• Google Calendar API Docs
• OAuth2 for Server Apps