Step 2: Clear & Exclusive Responsibilities

Imagine a restaurant where the chef also takes orders, the waiter also cooks, and the cashier also serves food. Chaos, right?

Your system components need mutually exclusive responsibilities - like a well-organized restaurant:

Feed System Example:

Web Server: "I serve HTTP requests to users. That's MY job."

• Handles user requests
• Fetches feed from database
• Sends response back

Generator: "I create candidate feeds. That's MY job."

• Pulls from post service
• Pulls from follow service
• Stores in temporary database

Aggregator: "I create final feeds. That's MY job."

• Processes temporary data
• Filters low-quality content
• Creates final feed for database

Pro Tip: When responsibilities overlap, bugs multiply and debugging becomes a nightmare.