Purpose
mcp-server-s3 is an MCP server for AWS S3, designed to let users manage S3 buckets and objects through an AI assistant, without having to memorize aws s3 ls, aws s3 cp, presigned URL syntax, and various flag parameters on the command line.
Main Capabilities
- List buckets
- Browse objects
- Read/upload text objects
- Download content
- Delete keys
- Generate presigned URLs
- Bucket inspection
Usage
This server can be used with Claude Desktop, Cursor, VS Code Copilot, and any MCP client, and reuses existing AWS credentials.
Add to .cursor/mcp.json.
Add to claude_desktop_config.json (macOS path: ~/Library/Application Support/Claude/claude_desktop_config.json).
Configure the MCP server to run npx mcp-server-s3, and provide AWS_REGION, AWS_ACCESS_KEY_ID, and AWS_SECRET_ACCESS_KEY in the environment.
The server uses the standard AWS credential chain:
- Environment variables: AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_REGION
- Shared credentials file: ~/.aws/credentials
- IAM role: when running in EC2, ECS, Lambda, or similar environments
Set AWS_REGION (defaults to us-east-1), and ensure the credentials have the necessary S3 permissions: s3:ListBuckets, s3:ListBucket, s3:GetObject, s3:PutObject, s3:DeleteObject, s3:HeadBucket.
This repository is an Agent Plugins 1.0.0 package: plugin.json, a portable mcp.json, and skills/ are released together with the MCP server.
For Cursor, clone the repository and copy or symlink it to ~/.cursor/plugins/local/mcp-server-s3, then reload the window. Skills and MCP will appear under Customize > Plugins.
Applicable Scenarios and Example Prompts
- "List all my S3 buckets"
- "Show me the files in my-bucket/uploads/"
- "Download the config.json from my-bucket"
- "Upload this content to my-bucket/notes.txt"
- "Generate a presigned URL for this file that expires in 1 hour"
Limitations
- Agent Plugins v1 does not include OAuth or AWS SSO wiring. AWS_REGION and credentials must be set in the MCP client host via environment variables or ~/.aws/credentials.
- There is no one-click installation, because keys remain in environment variables.
- AWS keys cannot be embedded in a portable installation link; use the JSON under Quick Start.
FAQ
- What is mcp-server-s3? An MCP server for S3: list buckets and objects, read/upload text objects, delete keys, presigned URLs, and bucket inspection.
- How does authentication work? The standard AWS credential chain: environment variables, a shared credentials file, or an IAM role on the machine running the MCP server.
- Which environment variables should be set in the MCP configuration? At least AWS_REGION. Unless relying on ~/.aws/credentials or a role, AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY are usually also needed.
- Can it be installed in Cursor as an Agent Plugin? Yes, via ~/.cursor/plugins/local/mcp-server-s3. Make sure the Cursor process can read the same AWS credentials as the CLI.
- Why is there no one-click Cursor button? AWS keys cannot be embedded in a portable installation link. Please use the JSON under Quick Start.
MIT © 2026 Ofer Shapira
