Backblaze B2 MCP Server — MCP server for Claude Code: buckets, files
Backblaze's official MCP server puts B2 storage in your agent's hands: buckets, objects, application keys, Object Lock. Handy when you want to inspect a bucket or push a file without leaving the chat.
claude mcp add --env B2_APPLICATION_KEY_ID=<B2_APPLICATION_KEY_ID> --env B2_APPLICATION_KEY=<B2_APPLICATION_KEY> --env B2_REGION=<B2_REGION> --env B2_MASTER_KEY_ID=<B2_MASTER_KEY_ID> --env B2_MASTER_KEY=<B2_MASTER_KEY> --transport stdio backblaze-b2-mcp-server -- npx -y @backblaze-labs/b2-mcpWhat Backblaze B2 MCP Server does
The server ships 40 tools. Seventeen go through the native B2 SDK and cover control-plane work the S3 API cannot do: buckets, application keys, Object Lock, event notifications, Partner/Groups. Nineteen use the AWS S3 SDK for the data plane — uploading, downloading, copying, listing and deleting objects, multipart transfers, presigned URLs. Four more are custom MCP code that computes reports over B2 data: storage growth, top egress, biggest files, abandoned uploads.
Destructive calls are gated. B2 secrets stay away from the model context under the default, file and off modes. Tool registration follows the key's capabilities, so a key only sees what it can actually do. Read-only resources are exposed too: b2://server-config, plus capability-gated b2://capabilities and b2://bucket/{bucketName}.
You need a Node.js runtime in the ^22.22.2 || ^24 || ^26 range and a B2 application key. A non-master key is enough for storage, S3 and key management. Partner/Groups tools throw without B2_MASTER_KEY_ID and B2_MASTER_KEY. Add B2_REGION when the region has to be known before authorization.
What it helps with
- list every bucket in a B2 account
- upload or pull an object over the S3-compatible API
- find the biggest files in a bucket
- check which uploads were never finished
- issue an application key with narrow rights
Example prompts for the agent
- List the buckets in my Backblaze B2 account and show the Object Lock settings on each
- Upload
report.pdfto thearchivebucket through the S3-compatible endpoint - Run the B2 report: how much did storage grow and which files drive egress
How to install Backblaze B2 MCP Server
Platform CLI
claude mcp add --env B2_APPLICATION_KEY_ID=<B2_APPLICATION_KEY_ID> --env B2_APPLICATION_KEY=<B2_APPLICATION_KEY> --env B2_REGION=<B2_REGION> --env B2_MASTER_KEY_ID=<B2_MASTER_KEY_ID> --env B2_MASTER_KEY=<B2_MASTER_KEY> --transport stdio backblaze-b2-mcp-server -- npx -y @backblaze-labs/b2-mcpReplace <…> with your own values
Platform CLI
codex mcp add backblaze-b2-mcp-server --env B2_APPLICATION_KEY_ID=<B2_APPLICATION_KEY_ID> --env B2_APPLICATION_KEY=<B2_APPLICATION_KEY> --env B2_REGION=<B2_REGION> --env B2_MASTER_KEY_ID=<B2_MASTER_KEY_ID> --env B2_MASTER_KEY=<B2_MASTER_KEY> -- npx -y @backblaze-labs/b2-mcpReplace <…> with your own values
Config file
{
"mcpServers": {
"backblaze-b2-mcp-server": {
"command": "npx",
"args": [
"-y",
"@backblaze-labs/b2-mcp"
],
"env": {
"B2_APPLICATION_KEY_ID": "<B2_APPLICATION_KEY_ID>",
"B2_APPLICATION_KEY": "<B2_APPLICATION_KEY>",
"B2_REGION": "<B2_REGION>",
"B2_MASTER_KEY_ID": "<B2_MASTER_KEY_ID>",
"B2_MASTER_KEY": "<B2_MASTER_KEY>"
}
}
}
}Replace <…> with your own values
Config file
{
"servers": {
"backblaze-b2-mcp-server": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@backblaze-labs/b2-mcp"
],
"env": {
"B2_APPLICATION_KEY_ID": "<B2_APPLICATION_KEY_ID>",
"B2_APPLICATION_KEY": "<B2_APPLICATION_KEY>",
"B2_REGION": "<B2_REGION>",
"B2_MASTER_KEY_ID": "<B2_MASTER_KEY_ID>",
"B2_MASTER_KEY": "<B2_MASTER_KEY>"
}
}
}
}Replace <…> with your own values
Platform CLI
gemini mcp add -e B2_APPLICATION_KEY_ID=<B2_APPLICATION_KEY_ID> -e B2_APPLICATION_KEY=<B2_APPLICATION_KEY> -e B2_REGION=<B2_REGION> -e B2_MASTER_KEY_ID=<B2_MASTER_KEY_ID> -e B2_MASTER_KEY=<B2_MASTER_KEY> backblaze-b2-mcp-server npx -y @backblaze-labs/b2-mcpReplace <…> with your own values
Step by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about Backblaze B2 MCP Server
How do I install Backblaze B2 MCP Server in Claude Code?
Run `claude mcp add b2-mcp -e B2_APPLICATION_KEY_ID=<B2_APPLICATION_KEY_ID> -e B2_APPLICATION_KEY=<B2_APPLICATION_KEY> -e B2_MASTER_KEY_ID=<B2_MASTER_KEY_ID> -e B2_MASTER_KEY=<B2_MASTER_KEY> -- npx -y @backblaze-labs/b2-mcp`, then restart the client.
What does Backblaze B2 MCP Server do?
It connects an MCP client to Backblaze B2 with tools for buckets, files, keys and Object Lock, plus reports on stored data. Which tools show up depends on what the key allows.
Which credentials are required?
A non-master application key handles storage, S3 and key management. Partner/Groups tools additionally need B2_MASTER_KEY_ID and B2_MASTER_KEY.
