Backblaze B2 Cloud Storage — a skill for Claude Code

A Claude Code skill for managing Backblaze B2 cloud storage directly from your terminal — list files, audit buckets, clean up stale data, and review security posture.

Built on the open Agent Skills specification. Compatible with Claude Code, Codex CLI, Cursor, Gemini CLI, and other skills-compatible agents.

Badge	Meaning
CI	GitHub Actions runs lint, tests, frontmatter validation, and pre-commit on every PR across Python 3.10–3.14.
License: MIT	Permissive open-source license — free to fork, modify, and ship.
Python 3.10–3.14	Tested on every currently-supported CPython version. Python 3.9 reached EOL in October 2025 and is no longer in the matrix.
Ruff	Linted and formatted with Astral's Ruff. Enforced via pre-commit.
Checked with mypy	Static type-checked. The audit script's public surface and the B2 JSON inputs are fully annotated.
pre-commit	Hooks for whitespace, JSON/YAML validity, ruff, markdownlint, yamllint, cspell, and mypy run on every commit.
Spell-checked: cspell	Markdown and Python prose are spell-checked with a project-specific allowlist.
Claude Code	First-class compatibility with Claude Code — auto-invoked when you mention B2 in chat.
Agent Skills	Conforms to the open Agent Skills SKILL.md specification — works in any compatible agent (Codex CLI, Cursor, Gemini CLI, etc.).
Backblaze B2	Targets the Backblaze B2 Cloud Storage platform via the official b2 CLI v4+.
GitHub stars	Community signal — give it a ⭐ if it's useful.

Features

• List & search objects across buckets with prefix filtering
• Storage audit — live vs. billable storage, breakdown by prefix + extension, configurable thresholds
• Hidden-cost detection — surfaces unfinished large uploads, old versions, and hide markers that still bill
• Cost estimation — monthly storage cost + potential savings after cleanup
• Duplicate detection — groups files by contentSha1 (true duplicates, not same-name)
• Stale & large-file flags — configurable --stale-days and --large-mb thresholds
• JSON output — --json flag for downstream analysis
• Cleanup with safety — mandatory dry-run + explicit "yes" confirmation before any deletion
• Security review — per-bucket checklist (type, SSE, CORS, object lock, replication, lifecycle coverage)
• Lifecycle rules — view and update expiration policies
• Guided setup — checks for a user-installed CLI, then walks through app-key creation and authorization
• Per-project config — different buckets and credentials per project

Install

Pick whichever fits your tooling. All methods install the same skill folder; only the delivery differs.

1. npx skills add — open spec CLI (recommended cross-agent)

Works with any Agent Skills-compatible client (Claude Code, Codex CLI, Cursor, Gemini CLI, Goose, OpenCode, etc.).

npx skills add backblaze-labs/claude-skill-b2-cloud-storage -g    # global
npx skills add backblaze-labs/claude-skill-b2-cloud-storage       # current project only

The -g flag installs system-wide (~/.claude/skills/ for Claude Code). Without it, the skill is scoped to the current project.

2. Claude Code plugin marketplace (recommended for Claude Code users)

Inside Claude Code:

/plugin marketplace add backblaze-labs/claude-skill-b2-cloud-storage
/plugin install b2-cloud-storage

This reads the .claude-plugin/marketplace.json in the repo and installs the skill plus any future plugins shipped from the same source.

3. GitHub Release tarball

Latest (always points at the most recent release):

curl -L https://github.com/backblaze-labs/claude-skill-b2-cloud-storage/releases/latest/download/b2-cloud-storage.tar.gz \
  | tar xz -C ~/.claude/skills/

Pinned to a specific version (deterministic deploys, air-gapped environments):

# Substitute the tag you want — see https://github.com/backblaze-labs/claude-skill-b2-cloud-storage/releases
TAG=vX.Y.Z
curl -L "https://github.com/backblaze-labs/claude-skill-b2-cloud-storage/releases/download/${TAG}/b2-cloud-storage-${TAG}.tar.gz" \
  | tar xz -C ~/.claude/skills/

Each release ships four artifacts: an unversioned b2-cloud-storage.tar.gz / .zip (used by the latest URL) and a -<tag> versioned pair for pinning.

4. Manual git clone

When you want to edit the skill in place or test changes locally:

git clone https://github.com/backblaze-labs/claude-skill-b2-cloud-storage.git /tmp/b2-skill \
  && cp -r /tmp/b2-skill/skills/b2-cloud-storage ~/.claude/skills/b2-cloud-storage \
  && rm -rf /tmp/b2-skill

Or, if you've already cloned the repo, from the repo root:

cp -r skills/b2-cloud-storage ~/.claude/skills/b2-cloud-storage

5. Marketplace-specific CLIs

Once the skill is listed on the respective directory:

npx @skill-hub/cli install b2-cloud-storage      # SkillHub
lhm install b2-cloud-storage                     # LobeHub (lobehub-cli)

See RELEASE.md for the full list of directories and their listing status.

Verify

ls ~/.claude/skills/b2-cloud-storage/SKILL.md

Then in Claude Code, restart the session and try > audit my-bucket for stale files — the skill is auto-invoked when you mention B2 in natural language.

Usage

The skill is auto-invoked when you mention B2 in natural language, or you can call it explicitly with /b2-cloud-storage:

> help me set up B2

> list everything in my-bucket

> audit my-bucket for stale files, duplicates, and unfinished uploads

> clean up files older than 90 days in my-bucket/logs

> run a security review on my public buckets

The audit script can also be run directly:

python ~/.claude/skills/b2-cloud-storage/scripts/storage_audit.py <bucket>
python ~/.claude/skills/b2-cloud-storage/scripts/storage_audit.py <bucket> --json
python ~/.claude/skills/b2-cloud-storage/scripts/storage_audit.py <bucket> \
  --stale-days 180 --large-mb 500 --prefix-depth 2

Note: You may need to restart Claude Code after installing the skill for it to be recognized.

Setup & API Keys

The skill verifies prerequisites and guides authorization on first use:

1. Checks for B2 CLI v4+ and asks you to install it if missing
2. Checks authorization — skips ahead if already configured
3. Guides API key creation:
   • Log in at secure.backblaze.com
   • Go to App Keys > Add a New Application Key
   • Set permissions (listBuckets, listFiles, readFiles for read-only)
   • Copy the keyID and applicationKey
4. Authorizes the CLI — runs b2 account authorize interactively (keys stay in your terminal, never in chat)
5. Verifies access with b2 ls

Credentials are stored by the B2 CLI in ~/.b2_account_info. The skill never sees or stores your keys.

Per-Project Configuration

Different projects can use different B2 buckets and credentials. On first use in a project, the skill asks which bucket to use and saves a config file at .claude/b2-config.json in your project root:

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

Field	Purpose
bucket	Default bucket for this project
prefix	Scope all operations to a prefix (e.g. data/models/)
accountInfoPath	Path to B2 credential file — use different keys per project

To use separate credentials per project, authorize into a project-specific file:

B2_ACCOUNT_INFO=~/.b2_account_info_myproject b2 account authorize

Then set accountInfoPath to ~/.b2_account_info_myproject in your project's config.

An example config file is included at skills/b2-cloud-storage/b2-config.example.json.

Note: This config file stores bucket names and file paths only — never API keys or secrets. Add .claude/b2-config.json to your .gitignore.

Security

• b2 account get and b2 key * commands are blocked (credential exposure)
• All deletions require --dry-run preview + explicit "yes" confirmation
• Bucket visibility changes (allPublic) require warning + confirmation
• All operations default to read-only
• API keys are never stored or displayed by the skill
• If you accidentally paste keys into chat, the skill warns you to rotate them

To report a security vulnerability, see SECURITY.md.

Privacy

This skill collects no data. It ships no telemetry and sends nothing to the skill's authors or any third party. Every operation runs locally: the skill invokes the user-installed b2 CLI, which talks only to Backblaze B2 using your own credentials. Those credentials are stored by the b2 CLI in ~/.b2_account_info and are never read, stored, or transmitted by the skill (see Security).

Data you store in or retrieve from Backblaze B2 is governed by Backblaze's Privacy Policy.

File Structure

claude-skill-b2-cloud-storage/
├── README.md
├── .github/workflows/ci.yml             # Lint + tests + frontmatter validation
├── tests/                               # Unit tests for the audit script
└── skills/
    └── b2-cloud-storage/                # Copy this folder to ~/.claude/skills/
        ├── SKILL.md                     # Skill definition and instructions
        ├── b2-config.example.json       # Example per-project config
        ├── scripts/
        │   └── storage_audit.py         # Audit: usage, versions, unfinished, cost
        └── references/
            ├── setup.md                 # First-use setup walk-through
            ├── cleanup-playbook.md      # Safe deletion procedure
            ├── security-review.md       # Per-bucket security checklist
            └── b2-cli-reference.md      # B2 CLI v4 command reference

Requirements

• Claude Code (or any Agent Skills-compatible tool)
• Python 3.10+ (CI tests against 3.10 – 3.14)
• User-installed B2 CLI v4+
• A Backblaze B2 account

License

MIT

Trademarks

This skill is an independent, community-maintained project. It is not affiliated with, sponsored, or endorsed by Anthropic. Claude and Claude Code are trademarks of Anthropic. Backblaze and Backblaze B2 are trademarks of Backblaze. References to these products are for identification and compatibility purposes only.