有状态 MCP 服务器功能
模型上下文协议 (MCP) 为 AI 应用程序提供了一种与外部数据和功能交互的标准化方式。本指南演示如何构建全面的 MCP 服务器,展示所有主要协议功能,以及如何在本地和部署到 Amazon Bedrock 时对其进行测试。 AgentCore
有关协议的完整详细信息,请参阅 MCP 规范
MCP 功能概述
MCP 服务器可以通过多种功能类型向客户端公开功能。本指南演示了以下功能:
- 资源
-
资源将服务器中的数据和内容暴露给 MCP 客户端。使用资源共享配置、参考数据或客户端或 AI 模型可以读取的任何上下文信息。资源由 URI 标识(例如,
travel://destinations)。 - 提示
-
提示是可重复使用的模板,用于为 AI 模型生成结构化消息。使用提示来标准化常见的互动,例如生成装箱单或学习目的地的当地短语。
- 工具
-
工具是 AI 模型可以调用以执行操作或检索信息的函数。工具范围从简单的数据查找到结合其他 MCP 功能的复杂多步骤工作流程。
- 引发
-
Elicitation 允许在工具执行期间由服务器启动的用户输入请求。当您的工具需要以交互方式收集信息(例如通过多回合对话收集旅行偏好)时,请使用 elicitation。
- 采样
-
采样允许服务器向客户端请求 LLM-generated 内容。当您的工具需要生成 AI-powered 文本(例如基于用户偏好的个性化旅行推荐)时,请使用采样。
- 进度通知
-
进度通知可让客户随时了解长期运行的操作。在搜索航班或处理预订等任务期间,使用进度报告提供实时反馈。
注意
引发、采样和进度通知等功能需要有状态的 MCP 会话。通过在运行服务器stateless_http=False时进行设置来启用状态模式。
会话管理
在状态模式下,服务器在初始化调用期间返回Mcp-Session-Id标头。客户端必须在后续请求中包含此会话 ID 才能维护会话上下文。如果服务器终止或会话过期,请求可能会返回 404 错误,并且客户端必须重新初始化才能获得新的会话 ID。有关更多详细信息,请参阅 MCP 规范中的会话管理
创建具有所有功能的 MCP 服务器
设置项目
-
创建具有所需依赖关系的
requirements.txt文件:fastmcp>=2.10.0 mcp -
安装依赖项:
pip install -r requirements.txt
使用以下代码创建名为 travel_server.py 的文件。该旅行预订代理在真实的工作流程中演示了所有 MCP 功能:
""" Travel Booking Agent - Stateful MCP Server Demonstrates all MCP features in a real-world travel booking workflow: - Elicitation: Collect trip preferences interactively - Progress: Show search progress for flights and hotels - Sampling: AI-generated personalized recommendations - Resources: Expose destination data and pricing - Prompts: Templates for packing lists and local phrases """ import asyncio import json from fastmcp import FastMCP, Context from enum import Enum mcp = FastMCP("Travel-Booking-Agent") # ============================================================ # DATA # ============================================================ class TripType(str, Enum): BUSINESS = "business" LEISURE = "leisure" FAMILY = "family" DESTINATIONS = { "paris": {"name": "Paris, France", "flight": 450, "hotel": 180, "highlights": ["Eiffel Tower", "Louvre", "Notre-Dame"], "phrases": ["Bonjour", "Merci", "S'il vous plait"]}, "tokyo": {"name": "Tokyo, Japan", "flight": 900, "hotel": 150, "highlights": ["Shibuya", "Senso-ji Temple", "Mt. Fuji day trip"], "phrases": ["Konnichiwa", "Arigato", "Sumimasen"]}, "new york": {"name": "New York, USA", "flight": 350, "hotel": 250, "highlights": ["Central Park", "Broadway", "Statue of Liberty"], "phrases": ["Hey!", "Thanks", "Excuse me"]}, "bali": {"name": "Bali, Indonesia", "flight": 800, "hotel": 100, "highlights": ["Ubud Rice Terraces", "Tanah Lot", "Beach clubs"], "phrases": ["Selamat pagi", "Terima kasih", "Sama-sama"]} } # ============================================================ # RESOURCES - Expose data to MCP clients # ============================================================ @mcp.resource("travel://destinations") def list_destinations() -> str: """All available destinations with pricing.""" return json.dumps({k: {"name": v["name"], "flight": v["flight"], "hotel": v["hotel"]} for k, v in DESTINATIONS.items()}, indent=2) @mcp.resource("travel://destination/{city}") def get_destination(city: str) -> str: """Detailed info for a specific destination.""" dest = DESTINATIONS.get(city.lower()) return json.dumps(dest, indent=2) if dest else f"Unknown: {city}" # ============================================================ # PROMPTS - Reusable templates for AI generation # ============================================================ @mcp.prompt() def packing_list(destination: str, days: int, trip_type: str) -> str: """Generate packing list prompt.""" return f"Create a {days}-day packing list for a {trip_type} trip to {destination}. Be practical and concise." @mcp.prompt() def local_phrases(destination: str) -> str: """Generate local phrases prompt.""" dest = DESTINATIONS.get(destination.lower(), {}) phrases = dest.get("phrases", []) return f"Teach me essential phrases for {destination}. Start with: {', '.join(phrases)}" # ============================================================ # MAIN TOOL - Complete booking with all MCP features # ============================================================ @mcp.tool() async def plan_trip(ctx: Context) -> str: """ Plan a complete trip using all MCP features: 1. Elicitation - Collect preferences 2. Progress - Search flights and hotels 3. Sampling - AI recommendations """ # -------- PHASE 1: ELICITATION -------- # Collect trip details through multi-turn conversation dest_result = await ctx.elicit( message="Where would you like to go?\nOptions: Paris, Tokyo, New York, Bali", response_type=str ) if dest_result.action != "accept": return "Trip planning cancelled." dest_key = dest_result.data.lower().strip() dest = DESTINATIONS.get(dest_key, DESTINATIONS["paris"]) type_result = await ctx.elicit( message="What type of trip?\n1. business\n2. leisure\n3. family", response_type=TripType ) if type_result.action != "accept": return "Trip planning cancelled." trip_type = type_result.data days_result = await ctx.elicit( message="How many days? (3-14)", response_type=int ) if days_result.action != "accept": return "Trip planning cancelled." days = max(3, min(14, days_result.data)) travelers_result = await ctx.elicit( message="Number of travelers?", response_type=int ) if travelers_result.action != "accept": return "Trip planning cancelled." travelers = travelers_result.data # -------- PHASE 2: PROGRESS NOTIFICATIONS -------- # Search for flights and hotels with progress updates total_steps = 5 await ctx.report_progress(progress=1, total=total_steps) # Searching flights await asyncio.sleep(0.4) await ctx.report_progress(progress=2, total=total_steps) # Comparing airlines await asyncio.sleep(0.4) await ctx.report_progress(progress=3, total=total_steps) # Searching hotels await asyncio.sleep(0.4) await ctx.report_progress(progress=4, total=total_steps) # Checking availability await asyncio.sleep(0.4) await ctx.report_progress(progress=5, total=total_steps) # Finalizing await asyncio.sleep(0.2) # Calculate costs flight_cost = dest["flight"] * travelers hotel_cost = dest["hotel"] * days * ((travelers + 1) // 2) # Rooms needed total_cost = flight_cost + hotel_cost # -------- PHASE 3: SAMPLING -------- # Get AI-generated personalized recommendations ai_tips = f"Enjoy {dest['name']}!" try: response = await ctx.sample( messages=f"Give 3 brief tips for a {trip_type} trip to {dest['name']} for {travelers} travelers, {days} days. Max 60 words.", max_tokens=150 ) if hasattr(response, 'text') and response.text: ai_tips = response.text except Exception: ai_tips = f"Visit {dest['highlights'][0]}, try local food, learn basic phrases!" # -------- FINAL CONFIRMATION -------- confirm = await ctx.elicit( message=f""" ========== TRIP SUMMARY ========== Destination: {dest['name']} Trip Type: {trip_type} Duration: {days} days Travelers: {travelers} COSTS: Flights: ${flight_cost} Hotels: ${hotel_cost} ({(travelers + 1) // 2} room(s) x {days} nights) TOTAL: ${total_cost} Confirm booking? (Yes/No)""", response_type=["Yes", "No"] ) if confirm.action != "accept" or confirm.data == "No": return "Booking cancelled. Your search results are saved for 24 hours." # -------- FINAL RESULT -------- highlights_str = '\n'.join(f' * {h}' for h in dest['highlights']) phrases_str = '\n'.join(f' * {p}' for p in dest['phrases']) return f""" {'=' * 50} BOOKING CONFIRMED! {'=' * 50} Booking Reference: TRV-{ctx.session_id[:8].upper()} TRIP DETAILS: {dest['name']} {days} days | {travelers} traveler(s) Trip type: {trip_type} FLIGHTS: ${flight_cost} Outbound: Day 1, Morning departure Return: Day {days}, Evening departure ACCOMMODATION: ${hotel_cost} {(travelers + 1) // 2} room(s) for {days} nights TOTAL PAID: ${total_cost} HIGHLIGHTS TO EXPLORE: {highlights_str} USEFUL PHRASES: {phrases_str} AI RECOMMENDATIONS: {ai_tips} {'=' * 50} Thank you for booking with Travel Agent! """ if __name__ == "__main__": print("=" * 60) print(" Travel Booking Agent - Stateful MCP Server") print("=" * 60) print("\n MCP FEATURES DEMONSTRATED:") print(" * Elicitation - Multi-turn trip preference collection") print(" * Progress - Real-time search progress updates") print(" * Sampling - AI-powered travel recommendations") print(" * Resources - Destination data and pricing") print(" * Prompts - Packing list and phrase templates") print("\n TOOLS:") print(" plan_trip - Complete booking flow with all features") print("\n RESOURCES:") print(" travel://destinations - All destinations") print(" travel://destination/{city} - City details") print("\n PROMPTS:") print(" packing_list - Generate packing suggestions") print(" local_phrases - Learn useful phrases") print("\n" + "=" * 60) print(f" Server: http://0.0.0.0:8000/mcp") print("=" * 60) mcp.run( transport="streamable-http", host="0.0.0.0", port=8000, stateless_http=False )
本地测试
启动服务器
-
运行 MCP 服务器:
python travel_server.py您应该会看到显示服务器在端口 8000 上运行的输出。
使用以下代码创建名为 test_client.py 的文件。此客户端测试所有 MCP 功能,包括资源、提示和主工具:
""" Travel Booking Agent - Test Client Tests all MCP features: Elicitation, Sampling, Progress, Resources, Prompts """ import asyncio import os import sys from fastmcp import Client from fastmcp.client.transports import StreamableHttpTransport from fastmcp.client.elicitation import ElicitResult from mcp.types import CreateMessageResult, TextContent async def elicit_handler(message: str, response_type, params, ctx): """Handle elicitation - interactive input.""" print(f"\n>>> Server asks: {message}") if isinstance(response_type, list): for i, opt in enumerate(response_type, 1): print(f" {i}. {opt}") choice = input(" Your choice (number): ").strip() response = response_type[int(choice) - 1] else: hint = " (number)" if response_type == int else "" response = input(f" Your answer{hint}: ").strip() if response_type == int: response = int(response) print(f"<<< Responding: {response}") return ElicitResult(action="accept", content={"value": response}) async def sampling_handler(messages, params, ctx): """Handle sampling - provide LLM response.""" print(f"\n>>> AI Sampling Request") prompt = messages if isinstance(messages, str) else str(messages) print(f" Prompt: {prompt[:80]}...") user_input = input(" Enter AI response (or Enter for auto): ").strip() if not user_input: user_input = "1. Book popular attractions early. 2. Try local street food. 3. Learn basic greetings!" print(f"<<< AI Response: {user_input}") return CreateMessageResult( role="assistant", content=TextContent(type="text", text=user_input), model="test-model", stopReason="endTurn" ) async def progress_handler(progress: float, total: float | None, message: str | None): """Handle progress notifications.""" pct = int((progress / total) * 100) if total else 0 bar = "#" * (pct // 5) + "-" * (20 - pct // 5) print(f"\r Progress: [{bar}] {pct}% ({int(progress)}/{int(total or 0)})", end="", flush=True) if progress == total: print(" Done!") async def main(): local_test = os.getenv('LOCAL_TEST', 'true').lower() == 'true' if local_test: url = sys.argv[1] if len(sys.argv) > 1 else "http://localhost:8000/mcp" token = None else: agent_arn = os.getenv('AGENT_ARN') if not agent_arn: print("ERROR: Missing AGENT_ARN environment variable") sys.exit(1) encoded_arn = agent_arn.replace(':', '%3A').replace('/', '%2F') endpoint = os.getenv('MCP_ENDPOINT', 'https://bedrock-agentcore.us-west-2.amazonaws.com') url = f"{endpoint}/runtimes/{encoded_arn}/invocations?qualifier=DEFAULT" token = os.getenv('BEARER_TOKEN') if not token: print("ERROR: Missing BEARER_TOKEN for remote testing") sys.exit(1) print(f" Agent ARN: {agent_arn}") print(f" Endpoint: {endpoint}") print("=" * 60) print(" Travel Agent - MCP Feature Test Client") print("=" * 60) headers = {} if token: headers["Authorization"] = f"Bearer {token}" print(f" Using auth token (len={len(token)})") transport = StreamableHttpTransport(url=url, headers=headers) client = Client( transport, elicitation_handler=elicit_handler, sampling_handler=sampling_handler, progress_handler=progress_handler ) try: await client.__aenter__() # Test Resources print("\n[1] Testing RESOURCES...") resources = await client.list_resources() print(f" Found {len(resources)} resource(s)") # Test Prompts print("\n[2] Testing PROMPTS...") prompts = await client.list_prompts() print(f" Found {len(prompts)} prompt(s)") # Test Main Tool (Elicitation + Progress + Sampling) print("\n[3] Testing PLAN_TRIP tool...") print(" (This tests Elicitation, Progress, and Sampling)\n") result = await client.call_tool("plan_trip", {}) print("\n" + "=" * 60) print("RESULT:") print("=" * 60) print(result.content[0].text) print("=" * 60) print(" ALL TESTS COMPLETED!") print("=" * 60) except Exception as e: print(f"\nERROR: {e}") return False finally: await client.__aexit__(None, None, None) return True if __name__ == "__main__": success = asyncio.run(main()) sys.exit(0 if success else 1)
运行本地测试
-
当服务器在一个终端中运行时,打开一个新终端并运行测试客户端:
python test_client.py -
客户端测试资源和提示,然后运行该
plan_trip工具,在完整的工作流程中演示启示、进度通知和采样。
部署到 Amazon Bedrock AgentCore
配置和部署
-
如果您尚未安装 AgentCore CLI,请安装:
npm install -g @aws/agentcore -
创建要部署的项目:
agentcore create --name TravelAgentDemo --protocol MCP -
部署代理:
agentcore deploy部署完成后,请记下输出中提供的代理 ARN。
测试已部署的代理
测试已部署的代理
-
设置所需的环境变量:
export AGENT_ARN='arn:aws:bedrock-agentcore:us-west-2:YOUR_ACCOUNT:runtime/YOUR_AGENT_NAME' export BEARER_TOKEN='your_bearer_token'用您的实际代理 ARN 和不记名令牌替换占位符。
-
在远程模式下运行测试客户端:
LOCAL_TEST=false python test_client.py -
客户端将测试资源、提示和
plan_trip工具。按照交互式提示完成预订,其中演示了已部署代理的招标、进度通知和采样。
Agent ARN: arn:aws:bedrock-agentcore:us-west-2:123456789012:runtime/TravelAgentDemo Endpoint: https://bedrock-agentcore.us-west-2.amazonaws.com ============================================================ Travel Agent - MCP Feature Test Client ============================================================ Using auth token (len=1034) [1] Testing RESOURCES... Found 1 resource(s) [2] Testing PROMPTS... Found 2 prompt(s) [3] Testing PLAN_TRIP tool... (This tests Elicitation, Progress, and Sampling) >>> Server asks: Where would you like to go? Options: Paris, Tokyo, New York, Bali Your answer: Paris <<< Responding: Paris >>> Server asks: What type of trip? 1. business 2. leisure 3. family Your answer: leisure <<< Responding: leisure >>> Server asks: How many days? (3-14) Your answer (number): 5 <<< Responding: 5 >>> Server asks: Number of travelers? Your answer (number): 2 <<< Responding: 2 Progress: [####################] 100% (5/5) Done! >>> AI Sampling Request Prompt: Give 3 brief tips for a leisure trip to Paris, France for 2 travelers... Enter AI response (or Enter for auto): <<< AI Response: 1. Book popular attractions early. 2. Try local street food. 3. Learn basic greetings! >>> Server asks: ========== TRIP SUMMARY ========== Destination: Paris, France Trip Type: leisure Duration: 5 days Travelers: 2 COSTS: Flights: $900 Hotels: $900 (1 room(s) x 5 nights) TOTAL: $1800 Confirm booking? (Yes/No) 1. Yes 2. No Your choice (number): 1 <<< Responding: Yes ============================================================ RESULT: ============================================================ ================================================== BOOKING CONFIRMED! ================================================== Booking Reference: TRV-A1B2C3D4 TRIP DETAILS: Paris, France 5 days | 2 traveler(s) Trip type: leisure FLIGHTS: $900 Outbound: Day 1, Morning departure Return: Day 5, Evening departure ACCOMMODATION: $900 1 room(s) for 5 nights TOTAL PAID: $1800 HIGHLIGHTS TO EXPLORE: * Eiffel Tower * Louvre * Notre-Dame USEFUL PHRASES: * Bonjour * Merci * S'il vous plait AI RECOMMENDATIONS: 1. Book popular attractions early. 2. Try local street food. 3. Learn basic greetings! ================================================== Thank you for booking with Travel Agent! ============================================================ ALL TESTS COMPLETED! ============================================================
提示
你也可以使用 MCP Inspector 来测试 MCP 服务器,这是一款用于测试 MCP 服务器的可视化工具。有关本地测试说明,请参阅使用 MCP 检查器进行本地测试。有关远程测试的说明,请参阅使用 MCP 检查器进行远程测试。