Library Overview¶

mcp-s3 can be used as a Go library to add S3 tools to your own MCP server.

Why Use as a Library?¶

Compose with other tools: Add S3 capabilities alongside your own custom MCP tools
Custom configuration: Full control over client creation and options
Extensibility: Add custom middleware, interceptors, and transformers
Integration: Use the integration interfaces to connect with other systems

Package Structure¶

Package	Description
`pkg/client`	S3 client wrapper around AWS SDK v2
`pkg/tools`	MCP tool implementations and Toolkit
`pkg/extensions`	Built-in middleware and interceptors
`pkg/multiserver`	Multi-connection management
`pkg/integration`	Cross-system integration interfaces
`internal/server`	Server factory (for reference)

Key Packages¶

pkg/client¶

Low-level S3 client wrapper around AWS SDK v2:

import "github.com/txn2/mcp-s3/pkg/client"

cfg := client.FromEnv()
s3Client, err := client.New(ctx, &cfg)

buckets, err := s3Client.ListBuckets(ctx)
content, err := s3Client.GetObject(ctx, "bucket", "key")

pkg/tools¶

MCP toolkit with all S3 tools:

import "github.com/txn2/mcp-s3/pkg/tools"

toolkit := tools.NewToolkit(s3Client,
    tools.WithReadOnly(true),
    tools.WithMaxGetSize(10*1024*1024),
)

toolkit.RegisterTools(mcpServer)

pkg/extensions¶

Built-in extensions for common needs:

import "github.com/txn2/mcp-s3/pkg/extensions"

// Read-only interceptor
readonly := extensions.NewReadOnlyInterceptor(true)

// Size limit interceptor
sizelimit := extensions.NewSizeLimitInterceptor(10*1024*1024, 100*1024*1024)

// Logging middleware
logging := extensions.NewLoggingMiddleware(logger)

pkg/integration¶

Interfaces for cross-system integration:

import "github.com/txn2/mcp-s3/pkg/integration"

resolver := integration.NewDefaultResolver("default", "my-bucket")
ref, err := resolver.ParseURI("s3://bucket/key")