Why Claude writes simpler code
simplify.ts
Anthropic accidentally leaked its Claude Code source code. Although the archived repo is easy to find, deeper analysis is not. The popular reactions are surface-level, while the technical reports read like a mindless doctor’s note written by Claude itself.
“It’s just a Bash wrapper.”
“Wait, that’s it? This is so hack-y.”
“There’s an undercover pet!”
“It’s a CLI with multiple layers of abstractions.”
I blame the lack of substance on the legal grey zone we’re in: linking the repo or sharing specifics would anger the copyright police. At least that’s what my $20/month lawyer/SWE tells me.
After reading through the repo, I nevertheless have to share this amazing fact:
Claude Code has its own skill for simplifying code (simplify.ts).
That’s not as flashy as those other headlines, but it’s still important.
Coding with Gemini, Grok, or Cursor can feel like a game of whack-a-mole. They’ll add the feature I asked for and pass the tests…but they also litter the code with unnecessary comments, dependencies, and abstractions. Claude’s submissions feel more elegant — as if it spent some extra time refining away the rough edges first.
Well, that’s exactly what they’re doing, and it’s all documented in simplify.ts. Instead of pointing you to that file, though, here is my own “simplify-code” SKILL.md, which is spiritually equivalent to Claude’s.
// Excerpt from my SKILL.md for simplifying code
---
name: simplify-code
description: Simplifies code by minimizing complexity, eliminating duplication, and prioritizing legibility for contributors. Use when implementing features, fixing bugs, refactoring, or when the user asks to simplify, clean up, make DRY, reduce complexity, or improve maintainability.
---
# Simplify Code
Favor minimal, legible implementations. Fewer lines and clearer structure make code easier to understand and maintain.
...You and I aren’t the only ones who recognize the importance of this simple engineering philosophy. Claude is used by a whopping 75% of the smallest companies (ie, the ones that are free to use whatever they want) and is already the overall market leader, despite being released only 11 months ago.
It seems we agree:
When it comes to code,
Less > more.
Simple > complex.
We’ve been willing to pay for simplicity with our wallets and our time all along. Now we finally know why.
A few bonus observations:
Mixed file names. You’ll see kebab-case, camel case, Pascal case, and lowercase all in the root directory alone.
A few massive files. The entry point is 4600+ lines long, for example.
Types, kinda. It’s 100% TypeScript, but they don’t rely on types very heavily. There are lots of optional properties, and types aren’t widely shared.
My instinct tells me these are less engineering conventions they settled on and more symptoms of an internal POC that rapidly evolved into a mainstream product.
What was your first reaction to the leaked code?
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