S3 MCP Server

#!/usr/bin/env node import { Server } from "@modelcontextprotocol/sdk/server/index.js"; import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js"; import { CallToolRequestSchema, ListToolsRequestSchema, ErrorCode, McpError, } from "@modelcontextprotocol/sdk/types.js"; import { S3Client, ListBucketsCommand, ListObjectsV2Command, GetObjectCommand, PutObjectCommand, DeleteObjectCommand, } from "@aws-sdk/client-s3"; import { z } from "zod"; const S3_REGION = process.env.S3_REGION || "auto"; const S3_ENDPOINT = process.env.S3_ENDPOINT; const S3_ACCESS_KEY_ID = process.env.S3_ACCESS_KEY_ID; const S3_SECRET_ACCESS_KEY = process.env.S3_SECRET_ACCESS_KEY; if (!S3_ENDPOINT || !S3_ACCESS_KEY_ID || !S3_SECRET_ACCESS_KEY) { console.error("Error: S3_ENDPOINT, S3_ACCESS_KEY_ID, and S3_SECRET_ACCESS_KEY environment variables are required."); process.exit(1); } const s3Client = new S3Client({ region: S3_REGION, endpoint: S3_ENDPOINT, credentials: { accessKeyId: S3_ACCESS_KEY_ID, secretAccessKey: S3_SECRET_ACCESS_KEY, }, }); const server = new Server( { name: "s3-mcp-server", version: "1.0.0", }, { capabilities: { tools: {}, }, } ); // Helper to convert stream to string const streamToString = (stream: any): Promise<string> => new Promise((resolve, reject) => { const chunks: any[] = []; stream.on("data", (chunk: any) => chunks.push(chunk)); stream.on("error", reject); stream.on("end", () => resolve(Buffer.concat(chunks).toString("utf8"))); }); server.setRequestHandler(ListToolsRequestSchema, async () => { return { tools: [ { name: "s3_list_buckets", description: "List all S3 buckets", inputSchema: { type: "object", properties: {}, }, }, { name: "s3_list_objects", description: "List objects in an S3 bucket", inputSchema: { type: "object", properties: { bucket: { type: "string", description: "The name of the bucket", }, prefix: { type: "string", description: "Optional prefix to filter objects", }, maxKeys: { type: "number", description: "Maximum number of keys to return (default 1000)", }, }, required: ["bucket"], }, }, { name: "s3_read_object", description: "Read the content of an object from an S3 bucket", inputSchema: { type: "object", properties: { bucket: { type: "string", description: "The name of the bucket", }, key: { type: "string", description: "The key (path) of the object", }, }, required: ["bucket", "key"], }, }, { name: "s3_put_object", description: "Upload an object to an S3 bucket", inputSchema: { type: "object", properties: { bucket: { type: "string", description: "The name of the bucket", }, key: { type: "string", description: "The key (path) of the object", }, content: { type: "string", description: "The content to upload", }, }, required: ["bucket", "key", "content"], }, }, { name: "s3_delete_object", description: "Delete an object from an S3 bucket", inputSchema: { type: "object", properties: { bucket: { type: "string", description: "The name of the bucket", }, key: { type: "string", description: "The key (path) of the object", }, }, required: ["bucket", "key"], }, }, ], }; }); server.setRequestHandler(CallToolRequestSchema, async (request) => { try { switch (request.params.name) { case "s3_list_buckets": { const command = new ListBucketsCommand({}); const response = await s3Client.send(command); return { content: [ { type: "text", text: JSON.stringify(response.Buckets || [], null, 2), }, ], }; } case "s3_list_objects": { const { bucket, prefix, maxKeys } = request.params.arguments as { bucket: string; prefix?: string; maxKeys?: number; }; const command = new ListObjectsV2Command({ Bucket: bucket, Prefix: prefix, MaxKeys: maxKeys, }); const response = await s3Client.send(command); const files = (response.Contents || []).map((item) => ({ key: item.Key, size: item.Size, lastModified: item.LastModified, })); return { content: [ { type: "text", text: JSON.stringify(files, null, 2), }, ], }; } case "s3_read_object": { const { bucket, key } = request.params.arguments as { bucket: string; key: string; }; const command = new GetObjectCommand({ Bucket: bucket, Key: key, }); const response = await s3Client.send(command); const body = await streamToString(response.Body); return { content: [ { type: "text", text: body, }, ], }; } case "s3_put_object": { const { bucket, key, content } = request.params.arguments as { bucket: string; key: string; content: string; }; const command = new PutObjectCommand({ Bucket: bucket, Key: key, Body: content, }); await s3Client.send(command); return { content: [ { type: "text", text: `Successfully uploaded to ${bucket}/${key}`, }, ], }; } case "s3_delete_object": { const { bucket, key } = request.params.arguments as { bucket: string; key: string; }; const command = new DeleteObjectCommand({ Bucket: bucket, Key: key, }); await s3Client.send(command); return { content: [ { type: "text", text: `Successfully deleted ${bucket}/${key}`, }, ], }; } default: throw new McpError( ErrorCode.MethodNotFound, `Unknown tool: ${request.params.name}` ); } } catch (error: any) { return { content: [ { type: "text", text: `Error: ${error.message}`, }, ], isError: true, }; } }); const transport = new StdioServerTransport(); await server.connect(transport);