Spec-Driven Development, A Waterfall model for AI Agent ?

[zjaveed]

Spec-Driven Developmentand Simple Agent Development

A quick decision guide for modern AI-assisted engineering

AI has expanded our toolbox. Today, teams can choose between Spec-Driven Development (SDD) — a structured, blueprint-first approach — and Simple Agent Development (SAD) — a fast, flexible prompting workflow.

Both are powerful.
Both have trade-offs.
Here’s how to pick the right one depending on your project.

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✅ Choose Spec-Driven Development when:

1. The project is complex or long-term

If you are building a backend service, platform component, API, or multi-module system, clarity and alignment matter.
SDD prevents architecture drift and ensures everyone (including AI agents) works from a shared spec.

2. Multiple teams or roles are involved

Product → Architect → Developer → Tester → Docs → AI Agents
A specification acts as the contract. Without it, context dissipates quickly.

3. Requirements must be stable, auditable, or compliant

SDD is ideal when you need:

• traceability

• governance

• predictable code behavior

• documentation for reviews or audits

4. Code quality and maintainability are more important than speed

Specs enforce consistent interfaces and reduce costly rewrites later.

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⚡ Choose Simple Agent Development when:

1. You need rapid prototyping or fast idea validation

Simple agent prompts allow you to test ideas within minutes — no heavy upfront work.

2. Requirements are unclear or evolving

When you are still exploring the problem, writing a detailed spec too early is expensive and often wrong.

3. The task is small, isolated, or disposable

Scripts, utilities, sample code, demos, experimentation — SAD is a perfect fit.

4. Creativity and exploration are more important than precision

Let the agent generate multiple variations and directions before locking anything down.

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🔄 When to use a Hybrid Approach

Most modern projects benefit from a mix:

• Start with simple agent exploration to understand the domain and clarify requirements.

• Once direction stabilizes, switch to spec-driven development for scalable implementation.

Think of it as:
Explore fast → define clearly → build predictably.

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🎯 Quick Decision Table

Situation	Recommended Approach
Complex architecture	Spec-Driven
Fast prototype needed	Simple Agent
Multi-team collaboration	Spec-Driven
Unclear requirements	Simple Agent → then SDD
High compliance / governance	Spec-Driven
Creative / R&D / experimentation	Simple Agent

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🧩 Final Thought

Spec-Driven brings order.
Simple Agents bring speed.
Smart teams use both intentionally, treating specs as an accelerator — not a barrier — and leveraging agents for what they do best: rapid iteration and exploration.

[tyler-dane]

I like the idea of having an evolving spec doc that agents update on their own. That way, the context is preserved without requiring the developer to pre-define the full spec.

Anyone already working like those, or know of a project that does? Would like to see if there's any tooling that could help this flow.