Expecting a single model to act as researcher, architect, execution engineer, and QA reviewer leads to context rot. The solution is cognitive decomposition: break the software development lifecycle into specialized agents—Research, Planning & Refinement, Execution, and Review—each restricted to a single cognitive task, with predictable handoff protocols and drop-in Markdown specs for Cursor, Claude Code, and Antigravity.

We are crossing the threshold into "System 2" AI: agentic workflows. For Ruby and Rails developers, this means moving from stateless chat to orchestrating autonomous agents that plan, reason, and execute. This guide covers tools vs skills, MCP, multi-agent pipelines, and production infrastructure.