ChatGPT Codex Claude Code Spec/Vibe Coding

AIM for Software teaches a practical, hands-on approach for using AI to develop better software specs and then using modern coding agents to generate working software from those specs.

Realizing the Promise of Agent-Based Code Generation

Coding agents such as Claude Code and Codex have transformed software development. Prompt-based ("vibe") coding demonstrated that developers could build surprisingly sophisticated applications simply by describing the desired application in natural language.

While remarkably powerful, vibe coding also revealed an important limitation. As applications grew larger and more complex, success depended less on clever prompts and more on giving the coding agent a complete, consistent spec.

Tired robot holding a sign that says Will Vibe Code For Tokens, with a cup labeled More Tokens Please

Spec/vibe-based coding builds on the strengths of vibe coding while overcoming many of its limitations. By combining the speed and creativity of vibe coding with a lightweight software spec, developers can produce more capable, reliable, and maintainable applications.

The AIM Layered Specification Structure

The AIM layered specification structure shown below provides a roadmap for developing complete software specs that guide modern coding agents.

Layered AIM software specification structure connecting user stories, use cases, domain models, state machines, user interface specs, database design, and tests

What kind of spec do coding agents work best from? It turns out they need the same kind of well-formed spec that helps human developers build the right software: clear requirements, use case narratives, a shared domain model or glossary, interface and behavior details, and a testing strategy that explains how the system should be verified. AIM organizes those elements into a lightweight layered structure so the coding agent is not just responding to prompts, but building from a coherent description of the software to be generated.

Good Specs Save Time and Tokens

As most of the world knows by now, one of the biggest practical issues with vibe coding is token cost, which can literally run into billions of dollars. Repeated rebuilds can burn through tokens quickly, especially when the coding agent is still trying to infer intent, structure, behavior, tests, and edge cases from an incomplete description.

Comparison showing lower token cost and faster progress when AIM SpecAgent develops the specification before Codex or Claude builds the software

One of the biggest costs of vibe coding is iteration. As applications become larger and more complex, developers often find themselves asking the coding agent to regenerate portions of the application over and over again as missing requirements and misunderstandings are discovered. Too often, requirements get discovered by accident as you bump into them during development. Each iteration consumes additional time and tokens. As the conversation grows, so does the cost of generating the next version.

Spiral model in action showing AI build, human test, vibecode tuning, spec updates, and revised specs across repeated loops

A good spec helps identify requirements before code generation begins, giving the coding agent a much clearer understanding of what to build. Fewer iterations mean lower token consumption, less debugging, and faster delivery of working software.

AI Helps Write the Spec. The Spec Guides the Coding Agent, Which Writes the Code.
Engineer and robot discussing template-driven generation of high-level system specifications and subsystem specifications

AIM for Software extends the principles of AI-Assisted MBSE (AIM) to software development. If you're new to AIM, learn more in the AI-Assisted MBSE (AIM) Training course. AIM uses AI to help develop system specs expressed in SysML v2. These specs include exactly the artifacts needed to spec software, including requirements, use case narratives, domain models, state machines, user interface specs, database design, and testing artifacts.

AI helps write the spec. The spec guides the coding agent, which writes the code.

Most of the effort shifts from repeated code generation to collaborative spec development with AI. Developing the spec can be done with general-purpose LLMs such as ChatGPT, while the coding agent focuses on what it does best—generating software from a well-defined spec.

The result is fewer iterations, software that's much closer to being right the first time, and dramatically lower token costs.

AI-assisted MBSE workflow using SysML v2 specifications to generate working software with Claude Code and Codex
What You'll Learn

By the end of this course, you will be able to:

  • Use ChatGPT to collaboratively develop complete software specs, including:
    • Requirements
    • Use case narratives
    • Domain models
    • User interface specs and database design
  • Use Codex or Claude Code to generate, evaluate, and refine a working software application.
  • Learn how better specs reduce iterations, debugging, and token costs.
  • Refine and regenerate applications by improving the spec.
  • Apply the AIM for Software methodology to your own software development projects.
Course Format

Duration: Two Days

Price: $1,295/student

Format: Instructor-led with extensive hands-on labs using ChatGPT and Codex (Claude Code may also be used).

Hands-On Workflow: Students develop a complete software spec with ChatGPT, then use that spec to generate, evaluate, and refine a working application with Codex or Claude Code.

Audience: Software developers, software architects, systems engineers, technical leads, and anyone interested in AI-assisted software development.

Prerequisites: Familiarity with software development concepts. No prior experience with AI coding agents or SysML v2 is required. Prior completion of the AI-Assisted MBSE (AIM) course is recommended, but not required.

Course Outline
Day 1 — Building the Spec
Module 1 – Working with AI Coding Agents
  • Vibe coding and coding agents
  • Why larger projects need better specs
  • Spec/vibe-based development
  • Overview of the AIM for Software methodology
Module 2 – Writing Better Specs with AI
  • AI-assisted spec development
  • The essential elements of a software spec
  • Preparing the spec for the coding agent
Day 2 — From Spec to Working Software
Module 3 – AI-Assisted Code Generation
  • Generating software from the spec
  • Evaluating the generated application
  • Updating the spec
Module 4 – Refining the Application
  • Refining the spec
  • Regenerating the application
  • Best practices and common pitfalls