What is Spec-Exact Development?
Understanding the concept, background, and solution
Definition
Spec-Exact Development (SED) is an AI-driven development paradigm in which the AI never deviates by even a single line from the specification.
"If the spec is wrong, the product is wrong - by design."
- The specification is the absolute standard
- AI neither interprets nor infers intent - it executes exactly what is written
- Specifications must be meticulously precise and complete
- The AI is given a complete architectural blueprint and reproduces it without deviation
Background
Created by Song Jaeho on November 4, 2025 to overcome the limitations of "vibe coding" and ensure consistent, predictable AI-driven development.
Problems with Prior Approaches
Vague Specifications
Specifications, context, and required skills are often described vaguely, leaving too much room for interpretation.
Fragmented Information
MCPs (Model Context Protocols) provide only fragmented pieces of information, making it difficult to maintain consistency.
Free Interpretation
AI freely interprets requirements, creating unpredictable outcomes that vary between implementations.
SED's Solution
Complete Blueprints
Provide AI with complete blueprints that cover every aspect of implementation. No room for guessing or assumption.
Precise Execution
AI follows the blueprints precisely without making inferences. Executes exactly what is specified, nothing more, nothing less.
Guaranteed Consistency
Specifications become the absolute standard that guarantees consistency across all implementations.
Key Takeaway
SED transforms AI from an unpredictable interpreter into a precise implementation tool by eliminating all ambiguity through complete, detailed specifications.
🤖 SED is Completely AI Agnostic
One of the most powerful aspects of SED is that it works with any artificial intelligence — regardless of the platform or vendor.
🔀 Platform Independence
SED specifications are not tied to any specific AI model or platform:
- OpenAI: GPT-4, GPT-3.5
- Anthropic: Claude (any version)
- Google: Gemini
- Meta: LLaMA
- Others: Mistral, Cohere, local models, etc.
♻️ Future-Proof Methodology
Your specifications remain valuable because:
- SED focuses on spec quality, not AI-specific prompts
- No vendor lock-in — your specs are completely portable
- You can switch AI providers without changing specifications
- Standards-based format (Markdown + YAML)
- Works with future AI models yet to be released
Universal Applicability
Whether you work with Claude today, switch to ChatGPT tomorrow, or use a custom open-source model in the future — your SED specifications remain unchanged and fully compatible. Only your system prompts need adjustment. This universality is the key advantage of treating specifications as the source of truth, independent of any particular AI implementation.