Coding sessions are longer and use more context. Claude Opus 5.5 is built with that in mind.
https://claude.com/blog/claude-opus-5-5-built-for-coding-sessions-that-use-more-context📌 Claude Opus 5.5:讓快取讀取成本砍 60%,因為你的 coding session 早就變了
TL;DR:Anthropic 官方數據顯示 coding session 變長變重,Opus 5.5 用定價、模型行為與 harness 三管齊下,把費用壓低約 40%。
過去半年,你跟 Claude Code 的互動模式其實悄悄變了:同一個 prompt,Claude 現在願意多花 3.3 倍的時間、多打超過 40% 的 model call 才回覆你。這不是模型變慢,而是開發者已經把 agent 丟去處理更龐大、更開放式的任務。Anthropic 在這篇部落格中,用實際使用數據解釋了 Claude Opus 5.5 為何是為這種新型態工作打造的。
🤔 coding session 正在變長、變重
Anthropic 拉取了 2026 年 3 月到 9 月的 Claude Code 聚合使用數據,發現幾個明顯趨勢:每個 session 的 prompt 數量維持穩定,但每個 prompt 的處理深度大幅上升。Claude 在每個 prompt 上工作的時間拉長 3.3 倍,model call 次數增加超過 40%,而中斷次數減少 68%。開發者連接 tool server 或使用 skill 的機率增加約一倍,直接貼文字進 prompt 的頻率則減少三分之一。每個請求的 context 量成長了 2.6 倍,輸入輸出 token 比例也從 189:1 拉高到 324:1。這些數字共同指向同一件事:開發者正把更有能力、資訊更充足的 Claude 導向更大、更開放式的任務,context engineering 的經濟效益也因此被放大。
🧩 三個讓長 session 更省錢的改動
Anthropic 指出三個讓長時間、高 context session 更划算的變化:
第一是定價本身。按 token 計費的輸入與輸出 token 價格降低 20%,而快取讀取(cache read)的 token 價格更是直接砍了 60%。這一點格外關鍵,因為快取讀取本來就佔 agentic 與 coding 工作成本的大宗,而過去六個月每個請求的 context 量又成長了 2.6 倍,代表帳單裡快取讀取所佔比例只會愈來愈高。截至發文當下,Opus 5.5 的快取 token 價格僅為競品的五分之一,同時效能表現更好。
第二是 Claude Code harness 本身更擅長運用快取。照理說 session 變複雜,快取命中率應該下降,但實際上輸入未命中快取(cache miss)的比例反而降低超過 50%。Anthropic 修補了會意外打斷快取的小地方(例如重新登入),也處理了較大動作造成的破壞(例如對話中途加入新指令、動態載入 tool)。針對 Opus 5.5 與 Fable 5.1 這類新模型,開發者現在可以在 session 中途切換 effort level 而不用重設快取;API key 與雲端供應商的使用者也能像訂閱用戶一樣設定一小時的快取存續時間,被 fork 出來的 subagent 更能直接沿用 parent 的快取,不必重新付費讀取同一份 context。
第三是完成同樣任務所需的輪次變少。Anthropic 引用 Zeta Labs 的案例:相較 Opus 5,他們在任務中所需的輪次與 tool call 次數更少,成本接近腰斬,同時完成的高難度任務數量翻倍。
💡 輪次省下的錢,比快取省下的更多
不過 Anthropic 也坦言這個優勢並非放諸四海皆準。文中引用 Addy 在《The cost of a task on Opus 5.5》的觀察:「在範疇明確的任務上,兩個模型花的輪次差不多,你拿到的就只是降價本身;差距最大的地方會出現在開放式任務,因為模型可能在錯誤方向上耗掉很多輪次。沒有一個數字能套用在所有 codebase 上,你得自己實測。」換句話說,簡單、機械式的任務不會因為換模型而省下輪次,但困難、開放式的任務,Opus 5.5 更有機會避免在錯誤路徑上燒 token——而少一輪對話省下的錢,通常比省一次快取讀取還多。另外值得一提的是,Opus 5.5 的輸出生成速度比 Opus 5 快超過 30%,雖然這不會直接降低 token 用量,但長時間無人看管執行時能大幅減少等待。
🎯 實務啟示:保護好你的快取命中率
Anthropic 建議開發者在 Claude Code 中執行 /usage 檢查自己有多少用量來自快取讀取,並針對性地保護這個數字:在 session 一開始就選定模型、避免中途切換;離開電腦前先執行 compact 而不是回來後才做;若使用 API key 或雲端供應商,長時間 session 應設定一小時的快取存續時間。隨著 agentic coding 從「不計成本衝規模」轉向「有效率地擴大規模」,把開放式、高 context 的工作交給 Opus 5.5,並養成這些保護快取的習慣,會是接下來降低帳單的關鍵路徑。
🔗 來源
- 標題:Coding sessions are longer and use more context. Claude Opus 5.5 is built with that in mind.
- 作者/機構:Michael Segner @ Anthropic
- 連結:https://claude.com/blog/claude-opus-5-5-built-for-coding-sessions-that-use-more-context
#Anthropic #ClaudeCode #ClaudeOpus #LLM #AIcoding #PromptCaching #DeveloperTools #AgenticAI #TokenPricing #SoftwareEngineering
原始資料 Claude Blog · 收集於 2026-09-24
摘要原文
Coding sessions are longer and use more context. Claude Opus 5.5 is built with that in mind. Our latest Opus model is priced and trained to optimize costs for how developers code now. Category Claude Code Enterprise AI Product Claude Code Claude Enterprise Date September 24, 2026 Reading time 5 min Share Copy link https://claude.com/blog/claude-opus-5-5-built-for-coding-sessions-that-use-more-context Author(s) Michael Segner We estimate Claude Opus 5.5 costs about 40% less to run than Opus 5 for typical workloads billed by token. For developers, exactly how those savings stack up matters. If you pay by the token, you will see the greatest cost difference for longer-running, higher context sessions–the exact type of Claude Code sessions that have become more prevalent in the last six months. This post will dive into the mechanics of what makes Opus 5.5 cost effective for how developers are coding today (and likely tomorrow). Claude Code trends We've pulled aggregate data on how developers have been using Claude Code from March to September 2026. As model capabilities improve, developers have been deploying agents in increasingly sophisticated ways. The number of prompts per session has been steady, but we found some interesting behaviors: Claude works 3.3x longer on each prompt with more than 40% more model calls per prompt. There are 68% fewer interruptions. Developers are about twice as likely to have a tool server connected or use a skill and a third less likely to paste text into a prompt. Context per request has grown 2.6x. The input to output token ratio moved from 189:1 to 324:1. All of this points to developers aiming a harder working, better informed Claude toward bigger, more open-ended tasks. For these types of sessions, the economic impact of context engineering is compounded. Simply put, Claude reads more tokens. You need to make sure all the context you are providing is necessary , and that as much of that context as possible is reading from cache . What makes Opus 5.5 cost effective for long, context heavy sessions There are three changes that make long-running, context-heavy sessions more cost effective: changes to pricing, model behavior, and the Claude Code harness. Let’s look at each. Cache is cheap For usage billed by the token, we reduced the cost of input and output tokens 20%, and we dropped the price of reading a cached token 60% . The latter reduction is significant because cache reads make up the majority of agentic and coding work costs. And as we just discussed, context per request has increased roughly 2.6x in six months, which means savings are trending in the right direction. The same price change for those billed by token saves more on today's Claude Code traffic than it would have six months ago, because more of the bill is now re-read context. As of the publication date, a cached token on Opus 5.5 costs a fifth of what it does compared to competing models while outperforming them. Claude Code is better at using the cache This is less specific to Opus 5.5, and more the result of many of the Claude Code features we’ve added in the last six months. Given the coding session trends we just discussed, you would expect a higher rate of cache misses, but the opposite is true. Input that misses the cache decreased by more than 50%. For example, we made it harder to unintentionally break your cache with smaller papercuts like refreshing a login. We also made it harder to break with larger actions, like adding instructions mid-conversation or loading tools on demand. For newer models like Opus 5.5 and Fable 5.1, you can now change effort levels during your sessions without resetting your cache. We also made the cache more useful for longer-running and delegated sessions. Developers on API keys and cloud providers can now set a one-hour cache lifetime (which subscribers already had) and forked subagents start from the parent's cache instead of paying for the same context again. The same task, but with fewer turns Opus 5.5 can need fewer turns than other models to accomplish the same task. Zeta Labs saw fewer turns and tool calls per task than Opus 5, but at nearly half the cost and twice as many of their hardest tasks completed. This won't hold for every task. In The cost of a task on Opus 5.5 , Addy wrote, "On a well-scoped task, both models finish in about the same number of turns, and the price cut is all you get. The gap should be biggest on open-ended tasks, where a model can spend many turns on the wrong idea. No single number holds for every codebase, so measure it." In other words, simple, short, and mechanical tasks will take the same amount of turns while longer, harder tasks have more potential for Opus 5.5 to avoid burning tokens on the wrong approach. A reduced turn is even more cost efficient than a cached token. Also worth noting, especially as Claude works longer unattended or uninterrupted, is that Opus 5.5 generates output more than 30% faster than Opus 5. While this doesn’t increase cache hit rate or use less tokens, it means waiting less on long runs. Protect your cached reads As agentic coding has matured, organizations have shifted from asking developers to scale at all costs to asking developers to scale efficiently. Run /usage in Claude Code to see how much of your usage is cached reads. Then protect that number: Pick your model at the start of a session rather than switching midway, Compact before you step away rather than after, and If you're on an API key or cloud provider, set the one-hour cache lifetime for long sessions. Point Opus 5.5 at the open-ended, context-heavy work where those habits compound, and see What a task costs on Opus 5.5 for the worked numbers. No items found. Prev Prev 0 / 5 Next Next eBook FAQ No items found. Transform how your organization operates with Claude See pricing See pricing See pricing Contact sales Contact sales Contact sales Get the developer newsletter Product updates, how-tos, community spotlights, and more. Delivered monthly to your inbox.
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