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Episode
407
Interview
Web News

My New Development Workflow | Spec Driven Development

Recorded:
September 11, 2025
Released:
September 23, 2025
Episode Number:
407

In this episode of the HTML All The Things Podcast, Matt explores his new development workflow centered around spec-driven development. With AI tools and coding agents becoming more powerful, the key to success isn’t just in writing code—it’s in writing clear, detailed specs first. Matt breaks down what spec-driven development is, why it works so well with large language models, and how it can transform the way developers approach projects. From lowering hallucinations and compressing prompts to enabling parallelization and automated testing, you’ll learn how structured specs can unlock more efficient, accurate development. Matt also shares real-world examples, including a spec for a dark mode toggle, and outlines how specs evolve into implementation docs for step-by-step coding.

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Who’s in This Episode?

Show Notes

Intro

  • With all the new AI tools and agents available I’ve been trying to find the most efficient way to program
  • One major breakthrough was realizing how important task requirements were before letting an LLM try to build something
  • I started writing and prompting more and more docs before even starting to write/generate code
  • Then saw the term spec-driven development pop up and that is what has taken over

What is Spec Driven Development

  • A document or set of documents that define the feature from a functionality, limitations, requirements and implementation details
  • Good to have code snippets and types created in the spec
  • Has completion criterion (When is this feature considered done?)
  • Would not have full code implementations, just smaller snippets with mix of code and pseudo code
  • Entire IDE’s are now being adjusted and developed to support this. Ex. Amazon’s Kiro (https://kiro.dev/)

Why Spec Driven Development Works Well With LLMs

  • Lowers hallucinations by fixing inputs/outputs (schemas, examples)
  • Improves prompt compression (shorter, clearer context = cheaper, faster)
  • Enables automated evals (acceptance criteria ⇢ tests ⇢ pass/fail gates)
  • Supports parallelization (split spec into small, independent contracts)
  • Easier handoffs (humans review spec; LLMs implement; repeat)

Example Spec

Dark Mode Toggle (Example Spec)

What’s next?

  • Use the specs to creation implementation documents
    • typically break the docs up by feature and keep each scope small
    • these docs will include todo’s and more detailed implementation startegies and code snippets for implementing the feature
  • Either implement the feature yourself or use these docs to prompt the LLM to begin implementation step by step while reviewing the todo’s it has tackled and hasn’t
  • Giving the LLM very strict scopes and smaller chunks to work on will give it a much high chance at success
  • You can also figure out which parts can be done in parallel once you create all the implementation docs and kick off multiple agents at once working on seperate features
  • Have the LLMs create tests first for even more accurate output



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