backblaze-labs/b2-mcp

A Model Context Protocol server for Backblaze B2 Cloud Storage. It lets any MCP-compatible AI client (Claude, and others) operate B2 through a focused, safe set of tools, currently incubating in Backblaze-Labs.
> **This is the official Backblaze B2 MCP server** — backblaze-labs/b2-mcp, published as @backblaze-labs/b2-mcp on npm and listed in the Official MCP Registry as io.github.backblaze-labs/b2-mcp. Community forks and third-party wrappers are not maintained by Backblaze.
**40 tools, assigned by backing category:**
- **Native B2 SDK (@backblaze-labs/b2-sdk) (17)** — B2 control-plane operations the S3 API has no equivalent for: buckets, application keys, Object Lock, event notifications, and Partner/Groups operations.
- **AWS S3 SDK (@aws-sdk/client-s3) (19)** — the S3-compatible data plane: object upload/download/copy/list/delete, multipart, bucket reachability, lifecycle, and presigned URL paths.
- **Neither SDK (custom MCP code) (4)** — repository-owned analytics over B2 reports and bounded live listings: storage growth, egress leaders, largest files, and abandoned uploads.
Destructive actions are gated, durable B2 secrets stay out of the model's context in the default/file/off modes, and registration is capability-aware so a key only ever sees tools it can use. The server also exposes read-only MCP resources: b2://server-config (non-secret, registered even during credential-less discovery), plus capability-gated b2://capabilities and b2://bucket/{bucketName}.
**Contents**
- Quick start
- B2 Skills pack
- Configuration
- Tools
- Package API Surface
- CLI Reference
- Resources
- Security & self-hosting
- Privacy
- Development
- Documentation
- Backblaze Labs ecosystem
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Quick start
**Prerequisites:** A supported Node.js runtime and a Backblaze B2 application key. A non-master key is all you need. The package engine range is ^22.22.2 || ^24 || ^26; CI runs on Node.js 22.23.1, 24, and 26. One non-master application key covers normal storage work (B2 native, S3, and key management); the Partner/Groups tools additionally need B2_MASTER_KEY_ID / B2_MASTER_KEY.
Option A — npx (Claude Desktop config)
Edit claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\, Linux: ~/.config/Claude/) and add:
Restart Claude Desktop and the B2 tools appear. If you need an explicit fallback region before authorization, add B2_REGION to the same env block (S3/report tools otherwise derive their region from the authorized B2 account response):
The canonical package name is @backblaze-labs/b2-mcp and the canonical binary is b2-mcp (b2-mcp-server is a transition alias); npx -y @backblaze-labs/b2-mcp runs it directly. See Configuration for the full variable list, and docs/product-specs/clients.md for a source-checkout setup and copy-paste configs for Cursor, VS Code, Cline, Windsurf, Zed, Continue, Goose, Claude.ai, and hosted (Streamable HTTP).
Option B — Claude Desktop extension (MCPB)
> Available once a release publishes the b2-mcp.mcpb asset (0.2.1 onward); earlier releases carry no bundle, so use Option A until the asset appears on the releases page.
Prefer no JSON editing? Download **b2-mcp.mcpb** from the latest release, then in Claude Desktop open **Settings → Extensions → Advanced settings → Extension Developer → Install Extension…** and select the downloaded file. Claude Desktop prompts for your **Application Key ID** and **Application Key** (Region and Master keys optional) — no config file to hand-edit. The bundle launches a version-pinned npx -y @backblaze-labs/b2-mcp@ (npm resolves the server on first run) so it always runs the exact published version. A one-click Claude Connectors Directory listing is in progress.
**Then just ask:**
> _"List the buckets this key can access."_ · _"Upload ./data.csv to reports/may-2026.csv."_ · _"Give me a 1-hour download link for backups/latest.tar.gz."_ · _"List files under logs/2026/."_
> **Why your client may show fewer than 40 tools:** registration is capability-aware. With a non-master key and no master key configured, the three Partner/Groups tools that require a master key are not surfaced, so tools/list reports 37; add B2_MASTER_KEY_ID / B2_MASTER_KEY on a Partner-entitled account for the full 40. A read-only key trims the surface further. Credential-free scanners see the full advertised surface, but every tools/call returns missing_credentials until valid B2 credentials are supplied.