Spec-Driven Development

Overview

Spec-Driven Development (SDD) is a methodology for producing enterprise-quality software using AI code generation. Instead of generating code and hoping it works, SDD specifies contracts, interfaces, and integration points first — then generates implementations that must satisfy those specifications.

Version 11.0 is the terminal version of the methodology for Layer 0 — the NestJS + Prisma + PostgreSQL backend stack. It was validated across 10 trials and 30 enterprise applications, tracking 34 failure modes to complete resolution. Research continues via layered convergence, extending SDD to full-stack development.

Author: Stephen Deslate, SJD Labs, LLC
Version: 11.0 — March 2026
Status: Layer 0 converged — layered convergence active

Executive Summary

A solo developer using SDD can produce enterprise-quality software at high velocity. The constraint is verification quality, not process quantity. Ten trials across 30 enterprise applications have proven this methodology self-correcting, converging from build-breaking structural failures (Trial 1) to zero new code-quality findings (Trial 10).

Convergence proof: Trial 10 produced 3 applications scoring 9.83–10.0 with zero new failure modes. Every convention from v1.0 through v10.0 was applied correctly. Layer 0 is complete — layered convergence continues the research.

Convergence

Each trial discovers failure modes in the generated code, produces conventions to eliminate them, and validates the fix in the next trial. This cycle repeated 10 times until no new code-quality failures were found.

The final trial validated all prior conventions across 3 enterprise applications built in parallel. All 34 previously identified failure modes remained resolved. No new code-quality failure modes were discovered. Layer 0 has reached full convergence.

With Layer 0 converged, the research extends via layered convergence — adding one domain at a time (frontend, infrastructure, testing, etc.) and running the same trial-based convergence process on each. There are 9 layers total, with Layer 1 currently active. Each layer converges independently before the next begins, targeting approximately 49 trials across all layers.

Phases

SDD follows a structured phase progression from specification through verification:

Conventions

SDD codifies 31 conventions (numbered 5.1–5.31) and 28 anti-patterns (6.1–6.28), each discovered through a specific failure in an earlier trial. Conventions are cumulative — each version adds to the prior set without removing existing rules.

Additionally, a 49-item reproducibility checklist ensures consistent application across projects and developers.

Scoring

Each application is scored across 6 equally-weighted dimensions covering security, testing, delivery, feature completeness, code quality, and documentation. The composite score ranges from 0 to 10.

Trial History

Full Document

This page presents the structure and results of SDD v11.0. The full methodology document — including detailed convention definitions, the anti-pattern index, phase gate checklists, scoring criteria, and the 49-item reproducibility checklist — is available on request.

Contact Stephen Deslate to discuss access, consulting, or licensing.