Anthropic ran the numbers: unguided Claude Code succeeds just 33% of the time.
The engineers who beat that odds don't write better prompts. They build structure around the agent before they type a single task.
Below is that exact structure: the 200-line CLAUDE.md, the slash commands, the writer/reviewer pattern, and the context rule seniors swear by.
Here's the full setup you need 👇
Before we dive in, I share daily notes on AI & vibe coding in my Telegram channel: https://t.me/zodchixquantðŸ§
## The mindset: structure beats prompting
The biggest shift is realizing the prompt isn't where the leverage is. Anthropic's internal teams found the gap between high-output engineers and everyone else isn't prompt quality, it's the structure built around Claude before execution starts.
That structure is a small set of files that control Claude's memory, behavior, and limits. Most people use only CLAUDE.md and miss the rest of the leverage. A senior setup uses all of it, and keeps each piece lean.
Four pieces below: the CLAUDE.md, the commands, the review pattern, and context control.
## 1. A lean CLAUDE.md, capped at 200 lines
CLAUDE.md loads into the system prompt and stays there the entire session, so every line costs context. The senior rule is to keep it under 200 lines and push detail into rule files that load only when relevant.
Your CLAUDE.md should hold the essentials:
## Project
One paragraph: what this is, the stack, the entry points.
## Conventions
- Use the simplest approach that works. No premature abstraction.
- Match existing patterns. Check a neighbor file before inventing.
## Commands
- Test: `npm test`
- Lint: `npm run lint`
## Rules
- Never push to main directly. Open a PR.
- Write a commit after each working step, so we can revert cleanly.
- Run the tests yourself before saying a task is done.The "use the simplest approach" line matters more than it looks. Claude over-engineers by default, adding abstraction layers and defensive code nobody asked for. One line in CLAUDE.md curbs it.
For anything longer, like detailed style guides, use .claude/rules/*.md with path globs so they load only when Claude touches matching files.
That keeps the always-on context small.
## 2. Slash commands for anything you do twice
At Anthropic, Security Engineering wrote 50% of all custom slash commands in the entire monorepo.
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