The Problem
Codebase entropy is the gradual degradation of code quality and consistency over time. With human developers, entropy accumulates slowly. With AI agents generating code at high velocity, entropy can accumulate 10× faster. Slightly different naming conventions, subtly inconsistent patterns, gradually diverging module structures.
How It Manifests
Naming drift: Some modules use getUserById, others use fetchUser, others use loadUserData.
Pattern drift: Error handling is done differently in each module.
Documentation drift: README says one thing, code does another.
Constraint drift: CLAUDE.md rules don’t match actual code patterns.
Critical in AI: Entropy is invisible until it’s severe. Each individual deviation is small. But after 1,000 agent-generated PRs, the cumulative drift can make the codebase feel like it was written by 100 different developers with different conventions.