Calendar Hold Sync

Implement hold mirroring from source Google calendars into target calendars to prevent double-booking.

Dependency

Require gog CLI in PATH.
Require user OAuth already configured for each account used in mappings.
Do not hardcode account emails, calendar IDs, or event IDs in code.

If gog is not configured, use this setup flow:

Run gog auth credentials /path/to/client_secret.json.
Run gog auth add you@gmail.com --services calendar.
Verify with gog auth list.

Only add additional Google services if you explicitly need them for another workflow.

Official gog references:

Homepage: https://gogcli.sh/
Source: https://github.com/steipete/gogcli

Config Contract

Use a user-provided JSON config file with this shape:

mappings[]
mappings[].name
mappings[].targetAccount
mappings[].targetCalendarId (default primary)
mappings[].sources[] with { account, calendarId }
mappings[].lookaheadDays (default 30)
mappings[].allDayMode: ignore|mirror
mappings[].overlapPolicy: skip|allow
hold.summary (default Busy)
hold.visibility (private)
hold.transparency (busy)
hold.notifications (none)
hold.reminders (none)
metadata.format (SYNCV1)
metadata.encoding (base64url(json))
metadata.fields: srcAccount,srcCalendar,eventId,start,end,title
scheduling.reconcileCron
scheduling.daytimeCron (optional)
scheduling.driftWindowDays (optional)
scheduling.watchIntervalSeconds (optional, default 20)
safety.dryRun
safety.maxChangesPerRun
safety.excludeIfSummaryMatches[]
safety.excludeIfDescriptionPrefix[]
gog.listEventsCmd|createEventCmd|updateEventCmd|deleteEventCmd (optional template overrides)
gog.allowCustomCommands (must be true to enable any gog.*Cmd override)

Custom Command Template Safety

When custom commands are enabled:

Only gog command templates are accepted.
Templates are rendered by replacing placeholders like {account} and {calendarId}.
Rendered commands are executed as argv tokens (no shell interpolation).
Keep gog.allowCustomCommands=false unless you fully trust and audit the config file.

Metadata Encoding

Store source linkage in hold description as:

SYNCV1:<base64url(JSON)>

JSON fields:

srcAccount
srcCalendar
eventId
start
end
title

Behavior

For each mapping:

Read source events in the active window.
Build desired hold events (private, busy, no reminders).
Detect existing managed holds by SYNCV1: prefix.
Reconcile idempotently:

Create missing holds.
Update drifted holds.
Delete stale holds.

If overlap policy is skip, do not create a hold when a non-managed target event overlaps.
Enforce maxChangesPerRun.
Respect dryRun.

Backfill

Backfill mode upgrades legacy hold events (matching expected hold signature but lacking SYNCV1) by attaching encoded metadata when a unique source match exists.

Command Surface

hold-sync validate-config
hold-sync reconcile --mapping <name>|--all [--dry-run]
hold-sync backfill --mapping <name>|--all [--dry-run]
hold-sync status --mapping <name>|--all
hold-sync install-cron --mapping <name>|--all
hold-sync watch --mapping <name>|--all [--dry-run] [--interval-seconds <n>]

Watch Cadence

Require watch cadence to be configurable from user config:

scheduling.watchIntervalSeconds controls watch poll frequency.
mappings[].lookaheadDays controls rolling watch/reconcile window.

Recommend baseline values:

watchIntervalSeconds: 900 (15 minutes)
lookaheadDays: 1 (24 hours)

Working Model

Use polling-based watch mode (hold-sync watch) for fast updates.
Expect update latency approximately equal to watchIntervalSeconds.
Treat this as self-hosted/operator-run automation.

Known Limits

Do not assume webhook/push subscriptions are present; current fast sync path is polling.
Keep periodic scheduled reconcile as fallback even when watch mode is enabled.

Required Tests

metadata encode/decode round-trip
overlap detection correctness
idempotent reconcile upsert/delete behavior

Attribution: gog setup flow adapted from:

Provider Notes (openclaw)

Use this variant when publishing to ClawHub/OpenClaw.

Keep instructions implementation-focused and command-oriented.
Keep dependency explicit: gog must be preconfigured by user.
Prefer deterministic script execution over speculative edits.
Avoid provider-specific APIs; treat the CLI as the boundary.