PulseFlow Tecnologia
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·6 min read·executive-brief·spec-driven-development·vibe-coding·spec-kit
PulseFlow Tecnologia

Spec-driven development: the mature answer to vibe coding

Two companies that compete directly for developers - GitHub and Microsoft - arrived at the same conclusion about the most expensive problem with "vibe coding": describing a goal, getting back a block of code, and only discovering afterward that the result never considered how the system should interact with what already existed. The answer both document is spec-driven development, and GitHub Spec Kit became the reference implementation.

The diagnosis: code is binding, a spec isn't

Microsoft sums up the central argument directly: "code is a binding artifact" - hard to decouple once implemented - while specs allow flexible experimentation before anything locks in. The company describes spec-driven development not as exhaustive documentation or waterfall planning, but as "version control for your thinking" - making technical decisions "explicit, reviewable, and evolvable," the same way code gets versioned.

The scenario that illustrates the cost of not having this

Microsoft cites a concrete scenario: a notification system where different team members made conflicting assumptions about how it should work - divergences a well-made spec would have caught before a single line of code was written, not afterward, in production. It's the same argument behind the contrast GitHub draws between vibe coding and spec-driven development: vibe coding accepts the first prompt's output; spec-driven development forces "clarity about how it should interact with existing systems" before accepting any implementation.

Three commands, one sequential flow

GitHub Spec Kit - now with more than 118,000 stars - organizes this around sequential commands: /specify defines functional requirements (the "what" and "why"), /plan defines technical decisions (the "how"), /tasks breaks the spec into implementable units. The tool itself, Specify CLI, is agnostic to which AI agent is used - it works with more than 30 different agents, from GitHub Copilot to Claude Code to Gemini.

What a spec allows that vibe coding doesn't

A detail Microsoft highlights that rarely comes up in discussions of generative AI in code: with the spec as the central artifact, it becomes possible to explore multiple implementations from the same spec - for example, comparing a component written in Rust against one written in Go, without rewriting the requirement from scratch for each attempt. That's structurally impossible in vibe coding, where the specification only lives inside a single attempt's prompt.

Why this is the mature answer, not just another tool

GitHub and Microsoft aren't inventing specs - architecture decision records (ADRs) and formal requirements already existed before generative AI. What changes is the systematic integration between spec and agent flow: the specification stops being a filed document and becomes the artifact the agent itself uses to generate, and the team uses to review, with traceability between the original requirement and the final code.

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