B2 Cloud Storage

B2 Cloud Storage Management

Manage Backblaze B2 cloud storage: list files, audit usage, estimate cost, clean up stale data, and review security posture.

Security Rules (MANDATORY)

1. Never run b2 account get, b2 account clear, or any b2 key * subcommand — these expose or mutate credentials.
2. Never read ~/.b2_account_info or any file matching *b2_account_info* — this is the B2 credential database (SQLite).
3. Always run b2 rm --dry-run before any real deletion; show the user what would be deleted and require an explicit "yes" before executing.
4. Never change a bucket to allPublic without first warning the user about the security implications and getting explicit confirmation.
5. Default to read-only — only perform writes or deletes when the user explicitly requests them.
6. Never store or write API keys, application keys, or account IDs to any file.
7. If the user pastes key values into the chat instead of the terminal, warn them immediately and recommend rotating the key. Never echo, store, or reference key values that appear in conversation.

First-Use Flow

1. Check the B2 CLI is installed: b2 version. If missing, install (pip install b2) — see references/setup.md for detail.
2. Verify the CLI is authorized: b2 ls. If it fails with an auth error, walk the user through references/setup.md.
3. Check for a per-project config at .claude/b2-config.json in the project root. If missing, ask the user for bucket + prefix and create one.

Interactive auth note

b2 account authorize (no args) reads keys from an interactive prompt, which agents cannot drive. The user has two options:

• Run it themselves in the terminal — in Claude Code they can type !b2 account authorize to execute directly in the session.
• Pass the keyID and applicationKey as positional args: b2 account authorize (keys will appear in shell history — less safe).
• Or set B2_APPLICATION_KEY_ID and B2_APPLICATION_KEY env vars before running B2 commands (recommended for scripts and CI).

Project-Level Config

Per-project config at .claude/b2-config.json:

{
  "bucket": "my-project-bucket",
  "prefix": "",
  "accountInfoPath": "~/.b2_account_info"
}

| Field | Purpose | |-------|---------| | bucket | Default bucket name for this project | | prefix | Optional prefix to scope all operations (e.g. data/models/) | | accountInfoPath | Path to B2 credential file — allows different keys per project |

If accountInfoPath differs from the default, prepend B2_ACCOUNT_INFO= when running b2 commands. This file stores bucket names and paths only — never API keys.

Common Actions

List & search

b2 ls b2://                    # top-level
b2 ls -r b2://                 # recursive
b2 ls -r --json b2://          # JSON for scripting
b2 ls --versions -r --json b2://    # include old versions + hide markers
b2 ls b2:///           # prefix-scoped

Inspect file

b2 file info b2id://

Storage audit (usage, stale, large, duplicates, cost)

python scripts/storage_audit.py 
python scripts/storage_audit.py  --json
python scripts/storage_audit.py  --stale-days 180 --large-mb 500 --prefix-depth 2

Reports live vs. billable storage, unfinished large files, old versions, hide markers, SHA1-based duplicates, and an estimated monthly cost.

Cleanup (destructive)

See references/cleanup-playbook.md. Never skip the dry-run step.

Lifecycle rules

b2 bucket get 
b2 bucket update --lifecycle-rules ''  allPrivate

Lifecycle rule JSON format is in references/b2-cli-reference.md.

Security review

See references/security-review.md for the full checklist (bucket type, SSE, CORS, object lock, replication, lifecycle coverage).

References

• references/setup.md — first-use setup walk-through (install, app-key creation, authorization)
• references/cleanup-playbook.md — safe deletion procedure with dry-run
• references/security-review.md — per-bucket security audit checklist
• references/b2-cli-reference.md — CLI v4 command reference

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: backblaze-labs
• Source: backblaze-labs/claude-skill-b2-cloud-storage
• License: MIT
• Homepage: https://blze.ai/storage

Install and usage instructions live in the source repository linked above.