Razor Mode

What is Razor Mode?

Razor is Krnl's YAGNI-first coding philosophy, baked directly into the agent's system prompt. It follows a strict productivity ladder that biases toward minimal code, standard library reuse, and zero unnecessary abstractions. Every line that isn't written is a line that can't break.

The Productivity Ladder

Razor Mode enforces a strict order of preference when the agent chooses a solution:

Three Tiers

Razor Mode has three levels, each progressively stricter about code minimalism:

Using Razor Mode

Control Razor Mode from within the agent session or via the VS Code extension:

/razor             # Show current mode
/razor minimal     # Enable minimal mode
/razor ultra       # Enable ultra mode
/razor off         # Disable Razor discipline

Why Razor Matters

AI coding agents naturally over-generate. They don't pay for the lines they write — but you do, in maintenance cost, cognitive load, and technical debt. Razor Mode is Krnl's answer: a simple, enforceable discipline that keeps the agent focused on what actually needs to exist. The result is smaller diffs, fewer bugs, and code that humans can still understand.

Before vs. After Razor

Consider the task: “add a simple email validation function”

# Over-engineered solution
class EmailValidator:
    def __init__(self, regex_pattern=None):
        self.pattern = regex_pattern or             r'^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$'
        self.logger = logging.getLogger(__name__)
    
    def validate(self, email):
        if not isinstance(email, str):
            raise ValidationError("Email must be string")
        if not re.match(self.pattern, email):
            self.logger.warning(f"Invalid email: {email}")
            return False
        return True
    
    def batch_validate(self, emails):
        return [self.validate(e) for e in emails]

# Minimal solution
import re

EMAIL_REGEX = r'^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$'

def is_valid_email(email: str) -> bool:
    return isinstance(email, str) and re.match(EMAIL_REGEX, email) is not None