Spec-First - Spec-driven agentic development plugin for AI coding agents

Show HN: Specification First Agentic Development Plugin and Prove

Spec-First is an MIT-licensed plugin that turns AI coding agents into disciplined engineers. Every change starts as a written spec in your repo, complete with file-and-line citations, done criteria, and a fresh reviewer that checks it against the actual code before a single line is built. Each spec gets its own branch and worktree, parallel specs build simultaneously, and commits only land when your verify stages pass. Decisions are logged automatically with what was chosen, what it beat, and why. Works with Claude Code, Codex, Cursor, and Copilot via AGENTS.md. Proven across 1,300+ specs in Agent Smith.