Spec-Driven Development Workflows

Overview

Spec-Driven Development (SDD) follows a clear workflow pattern: write specification → implement code → validate alignment. This approach ensures that design intentions and actual implementations stay synchronized, preventing drift and enabling fast, confident iteration—especially valuable when working with AI coding agents.

The workflow emphasizes maintaining a living specification that evolves with your system, allowing teams to work with clarity and shared understanding of what's being built.

The Fundamental SDD Workflow

Spec-Driven Development begins with specification first—defining what you're building before writing implementation code. The workflow follows three key phases:

1. Define the Specification

Teams first define the system specification before writing any implementation code. This specification serves as the shared understanding between all parties—different teams, stakeholders, and AI coding agents working on the project.

2. Implement Against the Specification

Once the specification is established and agreed upon, development can proceed with clarity. Teams build according to the specification, ensuring everyone is working toward the same vision without constant coordination overhead.

3. Validate Through Automated Checks

Automated validation ensures implementations match the specification. Tests verify that the system behaves as specified, catching misalignments early when they're cheapest to fix.

Evolution Beyond Initial Features

As systems grow beyond their first feature, the methodology's true value emerges. The key insight: evolution requires regression prevention, especially when autonomous coding agents optimize for speed.

Rather than allowing incremental changes to introduce drift, successful SDD workflows maintain a living specification that captures the system's current state. Each new feature must align with this evolving specification, ensuring the system grows coherently rather than fragmenting into disconnected implementations.

Specification as Source of Truth

The core principle: maintain the specification as the single source of truth for what the system does. This creates powerful alignment benefits:

• Shared understanding: Everyone works from the same definition of system behavior
• Clear intent: Specifications capture the "why" and "what" before implementation details
• Validation anchor: The specification provides a reference point to verify implementations
• AI agent alignment: Agents can reference the specification to stay on track with system goals

This clarity is critical for velocity—teams make progress confidently because they're aligned on what they're building.

Backward Compatibility as Guardrail

A crucial innovation in modern SDD workflows: backward compatibility checks happen at design time rather than discovery time.

By embedding compatibility validation into the planning phase (before any code generation), teams catch breaking changes when they're cheapest to fix. Automated validation tools can check proposed specification changes, preventing incompatibilities from reaching implementation.

This shifts quality checks left in the development cycle, enabling fast iteration without sacrificing stability.

Workflow Support in Different Tools

Various tools support the SDD workflow with different emphases:

• OpenSpec: Source of truth specification with delta specs for changes
• Kiro: Continuous validation between specification and implementation
• Github Spec Kit: GitHub-integrated workflow for specification evolution

Each tool provides mechanisms for the core workflow (define → implement → validate) while offering unique features for different team needs.

Learn More

• Spec-Driven Development with OpenSpec: Source of Truth

  Deep dive into source of truth specifications and workflow patterns.

• Analyzing Across Features with Systems Thinking

  Applying systems thinking to detect cross-feature conflicts in SDD workflows.

• Mind the Context Length in SDD

  Understanding the relationship between SDD and LLM context length management.