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Backblaze B2 MCP Server

Operate B2 buckets, objects, keys, Object Lock, notifications, and multipart uploads through MCP.

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Install Backblaze B2 MCP Server

Pick your client, then add it in one click or paste the config.

STDIONode.js
~/Library/Application Support/Claude/claude_desktop_config.json
claude_desktop_config.json
{
  "mcpServers": {
    "backblaze-b2-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@backblaze-labs/b2-mcp"
      ],
      "env": {
        "B2_APPLICATION_KEY_ID": "YOUR_VALUE_HERE",
        "B2_APPLICATION_KEY": "YOUR_VALUE_HERE"
      }
    }
  }
}

Settings → Developer → Edit Config, merge this into mcpServers, then fully quit and reopen Claude Desktop.

Values are written into the snippet above so you can paste it as is. They never leave your browser.

Automated check passed— started and listed 40 tools correctly (4d ago).

Overview

Backblaze B2 MCP Server MCP server exposes Backblaze B2 control-plane and S3-compatible storage operations to MCP clients. It can manage buckets, application keys, notifications, Object Lock settings, objects, versions, and multipart uploads through dedicated tools. Use it when an AI client needs to inspect or change B2 resources, with credentials and capability-aware tool registration controlling access. Some partner and group operations require separate Partner API credentials.

Use cases

  • List accessible B2 buckets
  • Create and configure storage buckets
  • Upload or copy S3-compatible objects
  • Manage object retention and legal holds
  • Create and revoke application keys

Key features

  • B2 bucket administration
  • Application key management
  • Object Lock controls
  • S3-compatible object operations
  • Multipart upload workflow
  • Capability-aware tool registration

Tools40

What Backblaze B2 MCP Server lets your agent do. Expand a tool for its parameters.

Verified live~14.3k tokens of context

Security & health

What it can reach and how reliably it runs — from our own checks, not the maintainer’s claims.

ActiveLast checked 1d ago

Recent health check succeeded.

9/9 checks healthy over the last 46d

What it can do

From the 40 tools this server returned when we ran it; 40 declare their own safety hints.

Can delete or modify data · 15Writes files · 5Handles credentials · 10Makes network requests · 40Read-only tools · 22
Network at startup4 connections
Files written at startup1
Install scriptsNone
npm provenanceSigned build
Package age66 days
Maintainers2

Observed 2026-10-24 in an isolated sandbox. A description of reach, not a security audit.

Supply-chain signal

No high-severity advisories surfaced by our automated scan.

Critical 0High 0Medium 0Low 0

Scanned 5d ago via OSV.dev · @backblaze-labs/b2-mcp (npm)

Adoption & maintenance

Factual signals from GitHub, npm, and our automated checks — not a rating.

GitHub stars46Stargazers on the source repository.
Last commit1d agoMost recent push to the default branch.
Availability100%Our rolling endpoint + install checks that succeeded.
Install checkPassedOur sandbox started it and listed its tools.
Tools exposed40Callable tools this server registers over MCP.

How Backblaze B2 MCP Server works

What Backblaze B2 MCP Server MCP server does

Backblaze B2 MCP Server connects MCP-compatible clients to Backblaze B2 Cloud Storage. It covers native B2 administration and S3-compatible object operations, so an agent can work with storage resources without requiring a separate custom integration.

The control-plane tools can authorize an account, inspect and manage buckets, list and revoke application keys, configure bucket notification rules, and change file legal-hold or retention settings. Partner and Groups operations are also available when the required Partner API credentials and account access are present.

The S3-compatible tools handle object metadata, listing, copying, deletion, version listing, and small inline transfers. Multipart tools support starting an upload, creating presigned part-upload URLs, listing parts, completing an upload, and aborting an upload.

How it works

Backblaze B2 MCP Server uses the B2 SDK for native B2 operations and the AWS S3 SDK for S3-compatible storage operations. MCP clients call individual tools rather than receiving unrestricted access to the underlying credentials.

The server registers tools according to available capabilities. A normal application key can cover storage work and key management, while Partner or Groups functions need master-key credentials for an appropriately entitled account. Read-only keys can expose a smaller tool surface. Destructive operations, such as deleting buckets, keys, or objects, include safety gates.

Small object uploads and downloads through the inline S3 tools are limited to 1 MiB. Larger transfers should use the multipart workflow where applicable. The server also provides read-only MCP resources for non-secret server configuration, capabilities, and bucket information.

Setup and configuration

Run the published npm package with a supported Node.js runtime and provide a Backblaze B2 application key. The required environment variables are B2_APPLICATION_KEY_ID and B2_APPLICATION_KEY. A non-master application key is sufficient for normal storage operations.

For Claude Desktop, configure an MCP server entry that runs npx -y @backblaze-labs/b2-mcp, then place the credentials in its environment block. The canonical executable is b2-mcp; b2-mcp-server is a transition alias. B2_REGION can provide an explicit fallback region, although S3 and report operations can derive the region after authorization.

Partner and Groups tools additionally require B2_MASTER_KEY_ID and B2_MASTER_KEY. Docker deployments use environment variables and default to HTTP transport; the published image should be pinned to a release version rather than relying on a mutable latest tag.

Tools and capabilities

  • Verify credentials and retrieve account information.
  • Create, inspect, update, and delete buckets, subject to bucket and safety constraints.
  • Read or replace public HTTPS bucket notification rules, with secrets redacted on reads.
  • List, create, and irreversibly revoke application keys.
  • Apply or clear object legal holds and retention settings.
  • Manage Partner group membership when Partner API access is configured.
  • List, copy, inspect, delete, and version objects through the S3-compatible interface.
  • Perform multipart uploads with presigned part URLs.

Limitations and notes

Inline S3 transfers are restricted to objects no larger than 1 MiB. Bucket deletion requires an empty bucket, and destructive actions may be blocked unless their safety conditions are satisfied. Notification targets must be public HTTPS endpoints.

The complete tool list is not necessarily visible to every client. Missing credentials, a read-only key, or absent master-key configuration can reduce the registered surface. Credential-free discovery may show advertised tools, but calls require valid B2 credentials.

Read the full README View source on GitHub

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Frequently Asked Questions about Backblaze B2 MCP Server

Backblaze B2 MCP Server is an MCP server that connects AI clients to Backblaze B2 Cloud Storage. Its main tools manage buckets, application keys, Object Lock, notifications, objects, versions, and multipart uploads through native B2 and S3-compatible APIs.

Install it by configuring an MCP client to run `npx -y @backblaze-labs/b2-mcp` and supplying `B2_APPLICATION_KEY_ID` and `B2_APPLICATION_KEY`. The README provides a Claude Desktop configuration example and also documents Docker deployment.

Yes, Backblaze B2 MCP Server works with Cursor. The project documentation names Cursor among the clients with setup guidance, alongside Claude Desktop, VS Code, Cline, Windsurf, Zed, and Continue.

It needs a Backblaze B2 application key ID and application key for normal storage operations. Partner and Groups tools additionally require `B2_MASTER_KEY_ID` and `B2_MASTER_KEY` with suitable Partner API access.

Yes, it can support larger uploads through multipart operations, but inline uploads are limited to 1 MiB. The multipart tools create an upload, provide presigned part URLs, list parts, complete the upload, or abort it.

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