The author revisits Fred Brooks’s classic software lessons in the era of AI coding agents, arguing that while agents wipe out accidental complexity, they amplify essential design challenges and generate unprecedented technical debt. He warns of new “agentic” tar pits, scope creep, and coordination overhead as AI swarms bloat codebases and shift the real work back to human judgment and taste.

• AI agents eliminate accidental complexity (boilerplate, tests, refactoring) but can't handle essential design work, which still requires human judgment
• Past ~100,000 lines of code, agents start "chasing their own tails," generating defensive boilerplate that clogs codebases—seen in McKinney's own projects and Posit's million-line Positron fork
• Coordination overhead doesn't disappear with AI, it just changes form: parallel agent sessions produce contradictory plans that force humans back into the loop
• Going from agent-generated prototype to production-ready code (testing, documentation, edge-case hardening) remains fundamentally human work