MCP（模型上下文协议）服务器和客户端使用 FastMCP 和 LangChain

本示例使用 FastMCP 构建本地 MCP 服务器，并创建一个使用 MCP 服务器中定义的工具的 LangChain 人工智能代理。

创建 MCP 服务器通常需要大量的样板代码和配置。FastMCP 使得设置 MCP 服务器变得更加容易。

LangChain MCP 适配器可以轻松连接到本地或外部 MCP 服务器。

本示例使用 FastMCP 创建本地 MCP 服务器，然后在客户端使用 LangChain MCP 适配器。由于此示例使用了 OpenAI 的大型语言模型 (LLM)，因此还使用了 LangChain 的 OpenAI 实现来与 LLM 通信。它创建了一个 LangGraph ReAct（推理和行动）代理。异步函数需要使用 asyncio。

由于此示例使用的是本地 MCP 服务器，因此连接（“传输”）使用 stdio（Python 标准输入/输出流）。外部 MCP 服务器则需要使用 Server-Sent Events (SSE) 或 WebSockets 传输而不是 stdio。

可以向 LLM 询问有关股票的任何问题。LLM 将调用 MCP 服务器中定义的工具，收集所有信息，并使用收集到的信息进行回答。

本示例询问：

使用股票代码 META 的公司是哪家？这家公司的收入在过去几个季度和几年里是如何发展的？

YFinance 为 MCP 服务器提供了股票市场工具。YFinance 是一个用于访问 Yahoo Finance 金融数据的 Python 库。YFinance 不需要 API 密钥。

此示例所需的 API 密钥

您需要一个 OpenAI API 密钥才能运行此示例。在此处获取您的 OpenAI API 密钥。将 OpenAI API 密钥插入 .env.example 文件中，然后将该文件重命名为 .env（删除 ".example" 后缀）。

运行此示例

从命令行运行应用程序：

python mcp_client.py

示例结果

从答案可以看出，MCP 服务器中定义的所有 3 个工具都已被使用：

Match 1:
{"address1": "1 Meta Way", "city": "Menlo Park", "state": "CA", "zip": "94025", "country": "United States", "phone": "650 543 4800", "website": "https://investor.atmeta.com", "industry": "Internet Content & Information", "industryKey": "internet-content-information", "industryDisp": "Internet Content & Information", "sector": "Communication Services", "sectorKey": "communication-services", "sectorDisp": "Communication Services", "longBusinessSummary": "Meta Platforms, Inc. engages in the development of products that enable people to connect and share with friends and family through mobile devices, personal computers, virtual reality and mixed reality headsets, augmented reality, and wearables worldwide. It operates through two segments, Family of Apps (FoA) and Reality Labs (RL). The FoA segment offers Facebook, which enables people to build community through feed, reels, stories, groups, marketplace, and other; Instagram that brings people closer through instagram feed, stories, reels, live, and messaging; Messenger, a messaging application for people to connect with friends, family, communities, and businesses across platforms and devices through text, audio, and video calls; Threads, an application for text-based updates and public conversations; and WhatsApp, a messaging application that is used by people and businesses to communicate and transact in a private way. The RL segment provides virtual, augmented, and mixed reality related products comprising consumer hardware, software, and content that help people feel connected, anytime, and anywhere. The company was formerly known as Facebook, Inc. and changed its name to Meta Platforms, Inc. in October 2021. The company was incorporated in 2004 and is headquartered in Menlo Park, California.", "fullTimeEmployees": 76834, "companyOfficers": [{"maxAge": 1, "name": "Mr. Mark Elliot Zuckerberg", "age": 40, "title": "Founder, Chairman & CEO", "yearBorn": 1984, "fiscalYear": 2024, "totalPay": 27219874, "exercisedValue": 0, "unexercisedValue": 0}, {"maxAge": 1, "name": "Ms. Susan J. S. Li", "age": 38, "title": "Chief Financial Officer", "yearBorn": 1986, "fiscalYear": 2024, "totalPay": 1948846, "exercisedValue": 0, "unexercisedValue": 0}, {"maxAge": 1, "name": "Mr. Javier Olivan", "age": 47, "title": "Chief Operating Officer", "yearBorn": 1977, "fiscalYear": 2024, "totalPay": 3835042, "exercisedValue": 0, "unexercisedValue": 0}, {"maxAge": 1, "name": "Mr. Andrew Bosworth", "age": 42, "title": "Chief Technology Officer", "yearBorn": 1982, "fiscalYear": 2024, "totalPay": 1923184, "exercisedValue": 0, "unexercisedValue": 0}, {"maxAge": 1, "name": "Mr. Christopher K. Cox", "age": 41, "title": "Chief Product Officer", "yearBorn": 1983, "fiscalYear": 2024, "totalPay": 1937677, "exercisedValue": 0, "unexercisedValue": 0}, {"maxAge": 1, "name": "Mr. Dana White", "title": "Independent Director", "fiscalYear": 2024, "totalPay": 272, "exercisedValue": 0, "unexercisedValue": 0}, {"maxAge": 1, "name": "Mr. Aaron A. Anderson", "title": "Chief Accounting Officer", "fiscalYear": 2024, "exercisedValue": 0, "unexercisedValue": 0}, {"maxAge": 1, "name": "Mr. Atish Banerjea", "age": 58, "title": "Chief Information Officer", "yearBorn": 1966, "fiscalYear": 2024, "exercisedValue": 0, "unexercisedValue": 0}, {"maxAge": 1, "name": "Ms. Jennifer G. Newstead J.D.", "age": 53, "title": "Chief Legal Officer", "yearBorn": 1971, "fiscalYear": 2024, "totalPay": 3079624, "exercisedValue": 0, "unexercisedValue": 0}, {"maxAge": 1, "name": "Mr. Henry T. A. Moniz", "age": 59, "title": "Chief Compliance Officer", "yearBorn": 1965, "fiscalYear": 2024, "exercisedValue": 0, "unexercisedValue": 0}], "auditRisk": 10, "boardRisk": 10, "compensationRisk": 10, "shareHolderRightsRisk": 10, "overallRisk": 10, "governanceEpochDate": 1746057600, "compensationAsOfEpochDate": 1735603200, "executiveTeam": [], "maxAge": 86400, "priceHint": 2, "previousClose": 599.27, "open": 592.525, "dayLow": 586.58, "dayHigh": 596.0, "regularMarketPreviousClose": 599.27, "regularMarketOpen": 592.525, "regularMarketDayLow": 586.58, "regularMarketDayHigh": 596.0, "dividendRate": 2.1, "dividendYield": 0.36, "exDividendDate": 1741910400, "payoutRatio": 0.0792, "beta": 1.237, "trailingPE": 22.932838, "forwardPE": 23.213835, "volume": 10332250, "regularMarketVolume": 10332250, "averageVolume": 18515718, "averageVolume10days": 18570790, "averageDailyVolume10Day": 18570790, "bid": 586.18, "ask": 588.22, "bidSize": 1, "askSize": 1, "marketCap": 1506761506816, "fiftyTwoWeekLow": 442.65, "fiftyTwoWeekHigh": 740.91, "priceToSalesTrailing12Months": 8.844573, "fiftyDayAverage": 580.1932, "twoHundredDayAverage": 580.8713, "trailingAnnualDividendRate": 2.025, "trailingAnnualDividendYield": 0.0033791114, "currency": "USD", "tradeable": false, "enterpriseValue": 1455978577920, "profitMargins": 0.39113998, "floatShares": 2166796937, "sharesOutstanding": 2181270016, "sharesShort": 31512402, "sharesShortPriorMonth": 24545066, "sharesShortPreviousMonthDate": 1741910400, "dateShortInterest": 1744675200, "sharesPercentSharesOut": 0.0125, "heldPercentInsiders": 0.00089, "heldPercentInstitutions": 0.80194, "shortRatio": 1.45, "shortPercentOfFloat": 0.0145000005, "impliedSharesOutstanding": 2565530112, "bookValue": 73.337, "priceToBook": 8.008372, "lastFiscalYearEnd": 1735603200, "nextFiscalYearEnd": 1767139200, "mostRecentQuarter": 1743379200, "earningsQuarterlyGrowth": 0.346, "netIncomeToCommon": 66635001856, "trailingEps": 25.61, "forwardEps": 25.3, "enterpriseToRevenue": 8.546, "enterpriseToEbitda": 16.549, "52WeekChange": 0.24272108, "SandP52WeekChange": 0.08081472, "lastDividendValue": 0.525, "lastDividendDate": 1741910400, "quoteType": "EQUITY", "currentPrice": 587.31, "targetHighPrice": 935.0, "targetLowPrice": 466.0, "targetMeanPrice": 703.8915, "targetMedianPrice": 690.0, "recommendationMean": 1.45588, "recommendationKey": "strong_buy", "numberOfAnalystOpinions": 62, "totalCash": 70229999616, "totalCashPerShare": 27.932, "ebitda": 87979999232, "totalDebt": 49519001600, "quickRatio": 2.501, "currentRatio": 2.662, "totalRevenue": 170359996416, "debtToEquity": 26.763, "revenuePerShare": 67.349, "returnOnAssets": 0.17879999, "returnOnEquity": 0.39835, "grossProfits": 139297996800, "freeCashflow": 36658999296, "operatingCashflow": 96108003328, "earningsGrowth": 0.365, "revenueGrowth": 0.161, "grossMargins": 0.81767, "ebitdaMargins": 0.51644003, "operatingMargins": 0.41487, "financialCurrency": "USD", "symbol": "META", "language": "en-US", "region": "US", "typeDisp": "Equity", "quoteSourceName": "Nasdaq Real Time Price", "triggerable": true, "customPriceAlertConfidence": "HIGH", "longName": "Meta Platforms, Inc.", "exchange": "NMS", "messageBoardId": "finmb_20765463", "exchangeTimezoneName": "America/New_York", "exchangeTimezoneShortName": "EDT", "gmtOffSetMilliseconds": -14400000, "market": "us_market", "esgPopulated": false, "regularMarketChangePercent": -1.9957651, "regularMarketPrice": 587.31, "shortName": "Meta Platforms, Inc.", "hasPrePostMarketData": true, "firstTradeDateMilliseconds": 1337347800000, "postMarketChangePercent": 0.929666, "postMarketPrice": 592.77, "postMarketChange": 5.46002, "regularMarketChange": -11.960022, "regularMarketDayRange": "586.58 - 596.0", "fullExchangeName": "NasdaqGS", "averageDailyVolume3Month": 18515718, "fiftyTwoWeekLowChange": 144.66, "fiftyTwoWeekLowChangePercent": 0.3268045, "fiftyTwoWeekRange": "442.65 - 740.91", "fiftyTwoWeekHighChange": -153.59998, "fiftyTwoWeekHighChangePercent": -0.2073126, "fiftyTwoWeekChangePercent": 24.272108, "dividendDate": 1742947200, "earningsTimestamp": 1746043503, "earningsTimestampStart": 1753786740, "earningsTimestampEnd": 1754308800, "earningsCallTimestampStart": 1746046800, "earningsCallTimestampEnd": 1746046800, "isEarningsDateEstimate": true, "epsTrailingTwelveMonths": 25.61, "epsForward": 25.3, "epsCurrentYear": 25.53311, "priceEpsCurrentYear": 23.001898, "fiftyDayAverageChange": 7.1168213, "fiftyDayAverageChangePercent": 0.012266296, "twoHundredDayAverageChange": 6.4387207, "twoHundredDayAverageChangePercent": 0.011084591, "sourceInterval": 15, "exchangeDataDelayedBy": 0, "ipoExpectedDate": "2022-06-09", "averageAnalystRating": "1.5 - Strong Buy", "cryptoTradeable": false, "marketState": "PREPRE", "corporateActions": [], "postMarketTime": 1746575989, "regularMarketTime": 1746561600, "displayName": "Meta Platforms", "trailingPegRatio": 1.9916}

Match 2:
Tax Effect Of Unusual Items ... Operating Revenue
2025-03-31 21935371.559134 ... 41804000000.0
2024-12-31 -44365234.375 ... 47866000000.0
2024-09-30 1320000.0 ... 40155000000.0
2024-06-30 -18480000.0 ... 38682000000.0
2024-03-31 -18929140.520341 ... 36075000000.0

[5 rows x 45 columns]

Match 3:
Tax Effect Of Unusual Items ... Operating Revenue
2024-12-31 -81420000.0 ... 162779000000.0
2023-12-31 -64416000.0 ... 133844000000.0
2022-12-31 -15795000.0 ... 115801000000.0
2021-12-31 -23380000.0 ... 117208000000.0
2020-12-31 NaN ... NaN

[5 rows x 48 columns]请提供需要翻译的英文技术文档内容。您目前只提供了翻译要求，但没有给出具体的文档文本。请将文档文本一并提供，以便我为您进行准确的翻译。