The onboarding-doc vs SOP analogy for CLAUDE.md vs SKILL.md is the cleanest version of that distinction I have seen. One thing worth adding to the procedural-memory section: retrieval for SKILL.md is keyed on the description field, not the body. The agent decides whether to load a skill from that one description alone, so a skill with a great process and a vague description simply never fires. You can watch this at scale by browsing real SKILL.md files sorted by install count (disclosure, I run Skillselion: skillselion.com/skills ): the heavily-installed ones almost all spend the description on trigger conditions, "use when X", rather than summarizing the body. Which fits your consistency point: procedural memory only makes an agent consistent if the trigger fires reliably.