I'm working on SpecPilot (https://specpilot.dev), a spec-driven development layer that sits in front of Claude Code, Cursor, Copilot and the rest. It deliberately doesn't generate code. It scaffolds a .specs/ folder and hands the actual writing off to whatever agent you already use, so the specs become the thing the agent is held to instead of a prompt you retype every session.

Open source, free, no login, nothing to sell. I'm not trying to build a business on this. I just want agents to write better code, and that only happens when they have something firmer than a chat prompt to work against. CLI is here: https://github.com/girishr/SpecPilot

It started as a TypeScript CLI in January. Enough people told me they either didn't want a CLI or didn't know how to use one that I rebuilt the front door as a guided chat: 27 questions, runs fully offline in the browser, outputs the .specs/ tree plus an onboarding prompt for your IDE.

Recently shipped an MCP server so the agent can run the questionnaire itself rather than the human doing it, published to the official MCP registry and Smithery. Next is brownfield: point it at an existing repo and backfill specs from the code. Honest state of things: the Product Hunt launch got 4 votes and around 100 visitors, and I had no event tracking wired up, so I couldn't even tell how many of those generated anything. Fixed since. Usage is small but real, and it's coming through MCP rather than the web app, which I did not expect.

The part I keep circling back to is that spec generation is easy to copy. Spec enforcement is where the value is: checking a diff against the spec and failing loudly. Feedback welcome, especially from anyone who tried SDD on an existing codebase and gave up.