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S3Filesystem

Stores files in Amazon S3 or S3-compatible storage services like Cloudflare R2, MinIO, and DigitalOcean Spaces.

info

For interface details, see WorkspaceFilesystem Interface.

Installation
Direct link to Installation

npm install @mastra/s3

Usage
Direct link to Usage

Add an S3Filesystem to a workspace and assign it to an agent:

import { Agent } from '@mastra/core/agent';
import { Workspace } from '@mastra/core/workspace';
import { S3Filesystem } from '@mastra/s3';

const workspace = new Workspace({
  filesystem: new S3Filesystem({
    bucket: 'my-bucket',
    region: 'us-east-1',
    accessKeyId: process.env.AWS_ACCESS_KEY_ID,
    secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY,
  }),
});

const agent = new Agent({
  name: 'file-agent',
  model: 'anthropic/claude-opus-4-5',
  workspace,
});

Cloudflare R2
Direct link to Cloudflare R2

import { S3Filesystem } from '@mastra/s3';

const filesystem = new S3Filesystem({
  bucket: 'my-r2-bucket',
  region: 'auto',
  endpoint: `https://${process.env.R2_ACCOUNT_ID}.r2.cloudflarestorage.com`,
  accessKeyId: process.env.R2_ACCESS_KEY_ID,
  secretAccessKey: process.env.R2_SECRET_ACCESS_KEY,
});

MinIO
Direct link to MinIO

import { S3Filesystem } from '@mastra/s3';

const filesystem = new S3Filesystem({
  bucket: 'my-bucket',
  region: 'us-east-1',
  endpoint: 'http://localhost:9000',
  accessKeyId: 'minioadmin',
  secretAccessKey: 'minioadmin',
});

Constructor parameters
Direct link to Constructor parameters

bucket:

string
S3 bucket name

region:

string
AWS region (use 'auto' for R2)

accessKeyId?:

string
AWS access key ID. Optional for public buckets (read-only access).

secretAccessKey?:

string
AWS secret access key. Optional for public buckets (read-only access).

endpoint?:

string
Custom endpoint URL for S3-compatible storage (R2, MinIO, etc.)

prefix?:

string
Optional prefix for all keys (acts like a subdirectory)

id?:

string
= Auto-generated
Unique identifier for this filesystem instance

displayName?:

string
Human-friendly display name for the UI

readOnly?:

boolean
= false
When true, all write operations are blocked

Properties
Direct link to Properties

id:

string
Filesystem instance identifier

name:

string
Provider name ('S3Filesystem')

provider:

string
Provider identifier ('s3')

bucket:

string
The S3 bucket name

readOnly:

boolean | undefined
Whether the filesystem is in read-only mode

Methods
Direct link to Methods

S3Filesystem implements the WorkspaceFilesystem interface, providing all standard filesystem methods:

  • readFile(path, options?) - Read file contents
  • writeFile(path, content, options?) - Write content to a file
  • appendFile(path, content) - Append content to a file
  • deleteFile(path, options?) - Delete a file
  • copyFile(src, dest, options?) - Copy a file
  • moveFile(src, dest, options?) - Move or rename a file
  • mkdir(path, options?) - Create a directory
  • rmdir(path, options?) - Remove a directory
  • readdir(path, options?) - List directory contents
  • exists(path) - Check if a path exists
  • stat(path) - Get file or directory metadata

init()
Direct link to init

Initialize the filesystem. Verifies bucket access and credentials.

await filesystem.init();

getInfo()
Direct link to getinfo

Returns metadata about this filesystem instance.

const info = filesystem.getInfo();
// { id: '...', name: 'S3Filesystem', provider: 's3', status: 'ready' }

getMountConfig()
Direct link to getmountconfig

Returns the mount configuration for sandboxes that support mounting this filesystem type.

const config = filesystem.getMountConfig();
// { type: 's3', bucket: 'my-bucket', region: 'us-east-1', ... }

Mounting in E2B Sandboxes
Direct link to Mounting in E2B Sandboxes

S3Filesystem can be mounted into E2B sandboxes, making the bucket accessible as a local directory:

import { Workspace } from '@mastra/core/workspace';
import { S3Filesystem } from '@mastra/s3';
import { E2BSandbox } from '@mastra/e2b';

const workspace = new Workspace({
  mounts: {
    '/data': new S3Filesystem({
      bucket: 'my-bucket',
      region: 'us-east-1',
      accessKeyId: process.env.AWS_ACCESS_KEY_ID,
      secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY,
    }),
  },
  sandbox: new E2BSandbox({ id: 'dev-sandbox' }),
});

See E2BSandbox reference for more details on mounting.

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