Write Durable Instructions
Put project-wide non-negotiables in CLAUDE.md; everything else belongs in prompts, memory, or nowhere.
CLAUDE.md is for rules that should apply to every prompt in this project — non-negotiables, build commands, naming conventions, and gotchas a fresh assistant couldn't infer from the code. Per-task constraints belong in the prompt; user preferences belong in memory; finished work belongs nowhere. If the rule won't matter next month or to a different task, don't put it in CLAUDE.md.
Where you'll practice this
One Promptles scenario teaches this principle directly.
What Belongs in CLAUDE.md
You have five candidate facts about your project floating around in your head and in scattered prompts. They each need a home — CLAUDE.md (durable project rule), the prompt itself (this-task-only context), agent memory (user preference), or nowhere (finished work). Putting them…
Other principles in Context
Declare the Tools You Need
Name the tool or MCP server by name, and say what to do if it isn't reachable.
Describe Before You Prescribe
Describe the Data Shape
Claude can't clean data it can't picture.
Explain the Integration Point
Keep Memory Reusable
Save patterns and preferences that survive across sessions; never save snapshots of finished work.
Map to Real Components
Use Code Connect so it reuses your components, not new markup.