Files
AgentCompany/builtin-skills/software-engineer/clean-code/references/emerge-simple-design.md
T
ZacharyZhang-NY e74dafcd36 Silence render-disposed spam, unbreak bundled skills, drop board wake
Three independently ugly bugs that all fed the same log flood:

* Electron's `WebFrameMain.send` writes every "Render frame was disposed"
  to stderr via `console.error`. When the worker fans a second
  agent-event past a reloading renderer, we produced thousands of
  identical lines and stalled the main loop on stderr I/O. Added a
  `mainFrame.detached` guard so the send is short-circuited before
  Electron's own catch block fires, and installed a targeted filter in
  `suppress-warnings.ts` (now actually imported from the entry point)
  so the specific `console.error("Error sending from webFrameMain:"…)`
  noise never reaches the terminal. Any other payload still surfaces.

* `dispatchAgentMessage` accepted the human-reader sentinel as a wake
  target when an agent replied to `__board__` — `wakeAgentIfPossible`
  then called `db.getAgent("__board__")`, threw, and the dispatcher
  kept repeating on every send. Strip `HUMAN_SENDER_ID` at
  `resolveMessageWakeTargets`, and keep a defense-in-depth guard in the
  heartbeat so a stray caller (future automation fan-out) cannot
  reintroduce the crash.

* Pi's skills loader rejects any SKILL.md whose frontmatter `name`
  diverges from its parent directory. The four bundled `my-writing-style`
  copies declared `name: writing-style-skill`, so every install emitted
  a warning and dropped the skill. They also lived as orphan gitlinks
  (mode 160000 without .gitmodules), and the global `*.md` gitignore
  hid every other SKILL.md from version control. Fixed the frontmatter
  to match the dir, converted the dangling submodules to plain trees,
  and allowlisted `builtin-skills/**/*.md` so a fresh clone carries the
  catalogue instead of silently losing it.
2026-04-20 08:13:48 -04:00

2.2 KiB

title, impact, impactDescription, tags
title impact impactDescription tags
Follow the Four Rules of Simple Design HIGH prevents over-engineering while maintaining quality emerge, simple-design, kent-beck, refactoring

Follow the Four Rules of Simple Design

Kent Beck's four rules of Simple Design, in order of priority:

  1. Passes all tests — correctness is non-negotiable
  2. Reveals intent — code is clear and expressive
  3. No duplication — every concept has a single representation
  4. Fewest elements — remove anything that doesn't serve the first three

Incorrect (over-engineered for imaginary requirements):

// Single implementation with unnecessary abstraction layers
public interface PaymentProcessor {}
public interface PaymentProcessorFactory {}
public abstract class AbstractPaymentProcessor implements PaymentProcessor {}
public class PaymentProcessorFactoryImpl implements PaymentProcessorFactory {
    public PaymentProcessor create() {
        return new DefaultPaymentProcessor();
    }
}
public class DefaultPaymentProcessor extends AbstractPaymentProcessor {
    public void process(Payment payment) {
        gateway.charge(payment.getAmount());
    }
}

Correct (simplest design that works):

public class PaymentProcessor {
    private final PaymentGateway gateway;

    public PaymentProcessor(PaymentGateway gateway) {
        this.gateway = gateway;
    }

    public void process(Payment payment) {
        gateway.charge(payment.getAmount());
    }
}

Rule 4 is the most overlooked: After making code correct, expressive, and DRY, actively look for things to remove. Every class, method, and variable should justify its existence. If you have one implementation of an interface, question whether you need the interface. If a design pattern adds indirection without a current concrete benefit, remove it.

When more structure is justified:

  • When you have 2+ implementations today (not hypothetically)
  • When a framework requires it (e.g., dependency injection interfaces)
  • When tests need seams for mocking external dependencies

Reference: Clean Code, Chapter 12: Emergence