How to Explain Code with AI — Understand Any Codebase

What is AI code explanation?

AI code explanation uses language models to translate source code into plain English descriptions of what the code does, why it does it (if context is available), and what could go wrong. It's most useful when onboarding to a new codebase, reading legacy code without documentation, or understanding algorithms in unfamiliar languages.

AI is excellent at explaining what code does mechanically — step by step, without assumptions.

❌ Code nobody wants to touch

def memoize(fn):
    cache = {}
    def wrapper(*args):
        key = str(args)
        if key not in cache:
            cache[key] = fn(*args)
        return cache[key]
    return wrapper
# Legacy code, no comment, no docstring

✅ AI explains it instantly

# AI explanation of memoize():
# This is a memoization decorator. It wraps any function (fn) 
# and caches its return values. When wrapper() is called:
# 1. Converts all arguments to a string key
# 2. Checks if this exact set of arguments was called before
# 3. If yes, returns the cached result (fast)
# 4. If no, calls the original function, stores the result, returns it
# Net effect: expensive functions are only computed once per unique input.

The quality of AI explanation depends heavily on how you ask. These templates get consistently good results.

LearnCodeGuide has a dedicated 'Explain Code' mode that gives structured, plain-English explanations for any snippet.