2026 Q1 is the year developers still build the agent harness. 2026 Q3 / 2027 is the year the LLM builds its own harness.

2026 Q1 is the year developers still build the agent harness.

2026 Q3 / 2027 is the year the LLM builds its own harness.

Today, every AI coding agent — Claude Code, Cursor, Codex, Gemini CLI, Aider, you name it — depends on the same hidden layer:

the files that brief the agent before it starts work.

AGENTS.md