Cloud Storage

## When to Use User needs to upload, download, sync, or manage files across cloud storage providers. Agent handles multi-provider operations with cost awareness. ## Quick Reference | Topic | File | |-------|------| | Provider-specific patterns | `providers.md` | | Authentication setup | `auth.md` | | Cost calculation | `costs.md` | ## Scope This skill covers operational cloud storage tasks across providers: - S3, GCS, Azure Blob, Backblaze B2, Cloudflare R2 - Google Drive, Dropbox, OneDrive, iCloud For storage architecture decisions, see `storage` skill. For S3-specific deep patterns, see `s3` skill. ## Critical Rules 1. **Verify operations completed** — API 200 ≠ success; check file exists with correct size/checksum 2. **Calculate ALL costs before large transfers** — egress fees often exceed storage costs; check `costs.md` 3. **Never delete without backup verification** — confirm backup exists AND is restorable before removing source 4. **Handle partial failures** — long operations fail mid-way; implement checkpoints and resume logic 5. **Rate limits vary wildly** — Google 750GB/day upload, Dropbox batch limits, S3 3500 PUT/s per prefix ## Authentication Traps - **OAuth tokens expire** — refresh before long operations, not during - **Service account ≠ user account** — different quotas, permissions, audit trails - **Wrong region/endpoint** — S3 bucket in `eu-west-1` won't work with `s3.amazonaws.com` - **MFA required** — some operations need session tokens, plan for interactive auth ## Multi-Provider Gotchas | Concept | Translates differently | |---------|----------------------| | Shared folder | Drive "Shared with me" ≠ Dropbox "Team Folders" ≠ OneDrive "SharePoint" | | File ID | Drive uses IDs; Dropbox uses paths; S3 uses keys | | Versioning | S3 explicit enable; Drive automatic; Dropbox 180 days | | Permissions | S3 ACLs + policies; Drive roles; Dropbox link-based | ## Before Any Bulk Operation - [ ] Estimated time calculated (size ÷ bandwidth) - [ ] Rate limits checked for both source AND destination - [ ] Cost estimate including egress + API calls - [ ] Checkpoint/resume strategy for failures - [ ] Verification method defined (checksum, count, spot-check)