A local, open-source tool that turns a rough idea, or a change to an existing codebase, into ordered development phases written for a coding agent, plus an optional UI mock and a deployment plan. Seven planning agents run in order; everything they write is a file under .spec4/ in your project. Apache 2.0. Bring your own model provider.
Latest release v1.5.0 — Spec4 v1.5.0 — a new interface, and a pipeline that explains itself · 16 Sept 2026
2 files for Codex, OpenCode and Claude Code: Spec4 AGENTS.md, Spec4 CLAUDE.md — 1,456 tokens loaded in every session.
AGENTS.md A 1,451 tok CLAUDE.md A 5 tok These files are robertcrowe/Spec4's own configuration — they tell Codex, OpenCode and Claude Code how to work on this repository, so they are not mods to install elsewhere. Copy one as a starting point and replace the parts that are about this project.