Anthropic's Official Context Engineering Guide: Just-in-Time Loading, Compaction, and Sub-Agent Isolation as the Three Pillars of Production Agent Performance

Anthropic Engineering·high signal

Anthropic's engineering team published their canonical context engineering guide establishing that context arrangement and quality determine agent performance more than any other factor. Three core strategies: (1) just-in-time context — maintain lightweight references (file paths, URLs, queries) and dynamically load data at runtime instead of pre-loading; (2) compaction — summarize conversation history when approaching context limits while preserving architectural decisions and unresolved issues; (3) sub-agent isolation — spawn specialists with scoped permissions receiving exactly the context needed. Anti-pattern: curating 'laundry lists' of edge cases — instead use diverse canonical examples.