# The New Rules of Context Engineering for Claude 5 > Source: > Published: 2026-08-01 16:31:57+00:00 Member-only story # The New Rules of Context Engineering for Claude 5 *A 1M-token window isn’t a 1M-token attention span. Here is the decision framework for RAG, memory, compaction, context editing, and subagents.* A 1M-token context window does not give your agent a 1M-token attention span. It gives your system a massive, expensive attic to hide stale tool output, obsolete decisions, and silent performance degradation until production reliability collapses. The real Claude 5 advantage is not more context — it is an operating system for deciding what the agent should forget. If you are using free version of Medium, [Please consider]use link to access this article for free.[, share this article with your friends to support my work. Thank you.]following and subscribing **In this Article you’ll learn** · [The 1M-Token Trap: Capacity Is Not Attention](#7228) · [The Context Routing Map: Five Jobs, Five Primitives](#294c) · [Start With the Bottleneck, Not the Feature](#9db2) · [Compaction Is a Handoff, Not a Trash Can](#da38) · [Forget Selectively: Editing and Memory Need Governance](#02bd) · [Subagents Earn Their Keep Only When Work Is Truly Separate](#43c1) · [Make Context a Measured Product Surface](#3427) · [Conclusion](#319d)