The Shift to Spec-Driven Development
October 22, 2025
The Problem
AI is now writing real code, but it still has no idea what we actually want. It produces results with confidence, even when they are misaligned or just plain wrong. In production environments, that overconfidence turns small mistakes into costly problems and wasted cycles.
AI coding tools rely on what we give them as input. When we hand them basic requirements without structure or boundaries, they have to infer architecture, dependencies, and intent. And they often guess incorrectly.
As codebases grow, the problem compounds. Agents hallucinate APIs, misread structure, or fix one issue by breaking three others. Teams waste hours reviewing AI output, rewriting code, and patching misunderstandings that never should have happened.
This is not a tooling problem. It is a context problem.
AI performs best when it starts with strong inputs. Trial-and-error loops in the IDE waste cycles and create as much rework as time saved. The same is true for quick prompts written only to unblock coding. Until we give AI a persistent, structured understanding of what we actually want and our existing product, it cannot be reliable.
The Solution
Spec-Driven Development gives AI and humans a shared language for intent.
It is a simple idea with profound consequences: specifications become the primary artifact, and code becomes their expression.
With Spec-Driven Development, each project acts as a container for features and knowledge. It holds the entire context for that area of the product or platform, including both the product definition and the technical architecture. We call them Living Projects that evolve continuously with every feature, task, and release.
A Living Project contains two core specs:
Requirements Spec – captures user intent, goals, acceptance criteria, and success metrics. It defines what success looks like for the feature or area of the product.
Tech Design Spec – maps those product requirements to the system design: APIs, data models, dependencies, integrations, and constraints. It defines how the system realizes the product intent.
This separation keeps intent and implementation clear while preserving alignment. Product managers, designers, engineers, and leaders all work within the same framework.
Inside each project, features (user stories) represent releasable slices of functionality. Features are broken into engineering tasks and prompt, each small enough to map to a single pull request. New features can be added iteratively after the initial release, using the existing project specs as context so the prompt passed to the coding agent has all historical decisions and structure.
With spec-driven development, every organization also maintains a system-wide platform spec, which is a living document that represents the current state of the entire product. It is initially generated from a deep understanding of the existing codebase and updated automatically as projects evolve. The platform spec is the ultimate map of the system’s behavior, boundaries, and intent and allows for new projects to kick off with a deep understanding of the existing product.
A Living Project structure that gets sent to an AI coding agent might look like this:
Being opinionated about how specs are written, stored, and iterated allows teams to move faster because convention eliminates ambiguity.
Core Principles
Specs as the Source of Truth
Functional and technical specs define the system. Code is their reflection.
Continuous Spec Integration
Specs evolve through updates, review, and versioning like code, ensuring the product never drifts from stated intent.
System Coherence
Project-level specs roll into a platform spec, keeping the product aligned as it grows.
Human Judgment, Machine Execution
Builders approve specs and guide direction; AI executes reliably within the guardrails.
Why This Matters
The software industry has reached a breaking point. Complexity has grown faster than our ability to manage it. Today, teams operate in fragmented systems with tickets in one tool, designs in another, specs in a third, code in a fourth, and AI sits awkwardly on top, trying to connect dots from disconnected systems.
Spec-Driven Development changes that. It creates a single layer of truth between human decision-making and AI execution. It turns planning and implementation into a continuous, data-driven loop.
With Living Projects, people, process, and AI all speaks the same language. The limitation is no longer technical ability but the clarity of human definition. When you formalize that intent in structured, versioned specs, you unlock scale without chaos.
The Future of Building
We’re entering a new phase of software creation where the roles of product, design, and engineering start to blur. AI is beginning to handle more of the mechanical work, and the way teams organize around it is changing.
In this next phase, a different kind of contributor is emerging. We call them builders. They still think like product managers and engineers, but their tools look different. Instead of handing off tickets or writing functions from scratch, they define intent and guide AI systems to bring that intent to life in code.
Builders can think in terms of outcomes. They use specs to express what should exist, what trade-offs matter, and what good looks like when it’s done. They manage projects that evolve and continuously release updates.
As AI takes on more of the coding, builders spend their time on what humans are uniquely good at: understanding users, reasoning about systems, and making creative and strategic decisions. The process starts to feel less like a chain of handoffs and more like a single conversation between people and machines working toward the same goal.
Specs become the shared language in that collaboration. AI becomes the translation layer that turns ideas into software.
The shift is still early, but it’s already underway. The teams that learn to work with clarity, context, and shared intent now will shape what building software looks like in the years ahead.