Phase 2: Context Engineering for Builders · 45 min · Claude Code · MCP · Python

Rules, Skills, and Persistent Context

Everything always-needed goes in the rules file. Everything sometimes-needed goes in a skill you load on demand. Confusing the two bloats every single session.

Real-world application: Structuring persistent context into always-loaded rules versus on-demand skills is a concrete architecture decision — describing it well signals you've actually built and maintained one of these systems, not just read about CLAUDE.md.

What you will learn

Distinguish rules files (CLAUDE.md, AGENTS.md, .cursorrules), skills, and MCP connections by when their content should load
Decide whether a piece of persistent context belongs in an always-loaded rules file or an on-demand skill
Explain MCP's role as a live context protocol rather than a copy-pasted, stale integration
Audit a real rules file for narrow, rarely-needed content that should be extracted into a skill

Introduction

Rules, Skills, and Persistent Context

Objective

Audit a real rules file's sections against an always-loaded token budget and flag narrow, rarely-needed sections that should be extracted into on-demand skills.

Unlock the full lesson

You've read the first 2 sections. The rest of this lesson covers The Problem, The Concept, Build, Check Yourself, Key Terms & Next — plus a hands-on lab, quiz, and project artifact.

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