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MCP協議評測:砍Session換來史上最大改版 | MCP Spec Review: No More Sessions, Biggest Update Yet

By Kit 小克 | AI Tool Observer | 2026-08-24

🇹🇼 MCP協議評測:砍Session換來史上最大改版

MCP規範在2026年7月28日正式發布史上最大改版,這份由Anthropic主導、目前已被Claude、ChatGPT、多數AI Agent框架採用的Model Context Protocol,這次直接砍掉沿用兩年的session交握機制,全面轉向無狀態架構。對開發AI Agent串接工具的工程師來說,這不是小版更新,而是要重寫連線邏輯的破壞性變更。

什麼是MCP規範的無狀態架構改版?

簡單說,這次MCP規範拿掉了initialize交握流程和Mcp-Session-Id header,改成每個請求自帶完整的meta資訊,讓伺服器不再需要記住「你是誰」。原本要靠sticky session、共享session store、甚至deep packet inspection才能撐住的remote MCP server,現在可以直接丟在最陽春的round-robin負載平衡器後面運作,靠tools/list回應快取跟Mcp-Method header分流。

這次MCP規範改版砍了什麼?破壞性變更有哪些?

除了session機制整個拔掉,還有幾個開發者要注意的破壞性變更:

  • Roots、Sampling、Logging三個功能被列為Deprecated,2027年前還能用,但已經是明牌要淘汰
  • 缺少resource的錯誤碼-32002改成JSON-RPC標準的-32602,寫死錯誤碼判斷的程式會直接壞掉
  • Tasks功能整個重做,從實驗性核心功能畢業成獨立extension,長任務改用tasks/gettasks/updatetasks/cancel明確操作,舊版2025-11-25實作要重新遷移
  • Extensions框架正式成為一級公民,用reverse-DNS命名、獨立版本控管,MCP Apps擴充也讓伺服器能直接送出sandboxed iframe裡跑的互動介面
  • 授權機制對齊OAuth 2.0與OpenID Connect,新增強制iss參數驗證

對開發者影響多大?現在該升級MCP規範嗎?

官方時程是Release Candidate鎖定在5月21日,正式規範7月28日上線,主要SDK預計十週內跟上Tier 1支援。如果你的MCP server還是session-based架構,或程式裡有寫死舊錯誤碼、舊Tasks API,建議先在測試環境驗證再上正式環境——這次改版幅度大到官方自己都說是「協議推出以來最大修訂」。反過來說,如果你的agent工具只是簡單呼叫、沒有深度依賴session狀態,衝擊其實不大,甚至能省掉不少維運sticky session的麻煩。

常見問題 FAQ

  • Q: 舊版MCP server會馬上壞掉嗎?
    A: 不會馬上,Deprecated功能到2027年前仍可運作,但官方已經明確給出淘汰時間表,建議提早規劃遷移。
  • Q: MCP規範改版跟Claude有關嗎?
    A: 有,MCP是Anthropic主導、Claude Code等工具採用的協議,Anthropic自家SDK也會優先跟進新規範。
  • Q: 一般使用者需要做什麼嗎?
    A: 不用,這次改版主要影響MCP server/client的開發者,一般使用ChatGPT或Claude的人不會感受到差異。

好不好用,試了才知道。


🇺🇸 MCP Spec Review: No More Sessions, Biggest Update Yet

The Model Context Protocol (MCP) spec just shipped its biggest revision since launch. The final 2026-07-28 specification, released July 28, 2026, rips out the two-year-old session handshake and replaces it with a fully stateless architecture — a breaking change for anyone building MCP servers or clients for Claude, ChatGPT, and other agent frameworks.

What Changed in the MCP Spec Stateless Core?

The MCP spec drops the initialize handshake and the Mcp-Session-Id header entirely. Every request now carries its own metadata via _meta fields, so any server instance can handle any request. A remote MCP server that used to need sticky sessions, a shared session store, or deep packet inspection at the gateway can now sit behind a plain round-robin load balancer and route on the Mcp-Method header.

What Are the MCP Spec Breaking Changes?

Beyond killing sessions, developers need to watch for:

  • Roots, Sampling, and Logging are now Deprecated — still functional through 2027, but on notice
  • The missing-resource error code changed from -32002 to the JSON-RPC standard -32602, breaking any hardcoded error handling
  • Tasks graduated from an experimental core feature to a full extension, with a redesigned lifecycle using tasks/get, tasks/update, and tasks/cancel — anything on the old 2025-11-25 implementation needs migration
  • Extensions are now first-class, with reverse-DNS identifiers and independent versioning; MCP Apps lets servers ship sandboxed iframe UIs
  • Authorization now aligns with OAuth 2.0 and OpenID Connect, adding mandatory iss parameter validation

Should You Upgrade to the New MCP Spec Now?

The release candidate locked May 21, 2026, and the final spec shipped July 28, 2026, with Tier 1 SDK support expected within ten weeks. If your MCP server still relies on session state, or your code hardcodes old error codes or the legacy Tasks API, test the migration before touching production — Anthropic itself calls this the largest revision of the protocol since launch. If your integration is a simple stateless tool call, the impact is minimal, and you might even shed the headache of maintaining sticky sessions.

FAQ

  • Q: Will my old MCP server break immediately?
    A: No — deprecated features keep working through 2027, but the clock is now ticking on migration.
  • Q: Is this MCP spec change related to Claude?
    A: Yes. MCP is led by Anthropic, and Claude Code and Anthropic own SDKs will be among the first to support the new spec.
  • Q: Do regular ChatGPT or Claude users need to do anything?
    A: No — this change mainly affects developers building MCP servers and clients, not end users of chat apps.

好不好用,試了才知道。

Sources / 資料來源

常見問題 FAQ

舊版MCP server會馬上壞掉嗎?

不會,Deprecated功能到2027年前仍可運作,但官方已公布明確的淘汰時間表,建議提早規劃遷移。

MCP規範改版跟Claude有關嗎?

有關,MCP由Anthropic主導、Claude Code等工具採用,Anthropic自家SDK也會優先支援新規範。

一般使用者需要做什麼嗎?

不需要,這次改版主要影響MCP server/client開發者,一般使用ChatGPT或Claude的人不會感受到差異。

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