Spec-Driven Development w Gemini CLI

This repo has some basic assets to experiment Spec-Driven Development using the Gemini CLI. You will act as a developer going from a raw Functional Specification to a deployed Pull Request in a single session.

Assets

• .gemini/commands/: Contains configuration files for custom commands (techspec, plan, build).
• GEMINI.md: Contains project rules and guidelines.
• js_codegen_instructions.md: Contains Gemini API coding guidelines for JavaScript/TypeScript.
• py_codegen_instructions.md: Contains Gemini API coding guidelines for Python.
• No application code.

Requirements

The GEMINI.md configuration and custom commands require the following extensions:

• Google Workspace
• Nano Banana
• GitHub

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Step 1: The Architect Phase (/techspec)

Goal: Transform a Functional Spec (Google Doc) into a Technical Spec (Google Doc).

1. Command:

   /techspec "Name of your functional specs doc" "Your desired technology stack and requirements"
   

2. What Happens:

   • The agent searches your Drive for the doc.
   • It reads the requirements.
   • It generates a Technical Specification including Data Models, API Routes, and Architecture based on your inputs.
   • Output: It creates a new Google Doc titled "Technical Specification - Application name" and gives you the link.

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Step 2: The Planning Phase (/plan)

Goal: Break the Technical Spec down into an atomic Implementation Plan.

1. Command:

   /plan "Name of your Tech spec doc"
   

   (Use the exact name of the doc generated in Step 1)

2. What Happens:

   • The agent reads the Tech Spec.
   • It creates a local file IMPLEMENTATION_PLAN.md.
   • It breaks the project into phases (e.g., Setup, Backend, Frontend, Polish).
   • It defines the Git strategy.

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Step 3: The Build Phase (/build)

Goal: Execute the plan and write the code.

1. Command:

   /build IMPLEMENTATION_PLAN.md "Name of your Tech spec doc"
   

2. What Happens (Iterative):

   • Execution: The agent iterates through the plan, initializing the project structure and writing the application code.
   • Visuals: It generates necessary visual assets (images, icons) as defined in the spec.
   • Progress: It updates IMPLEMENTATION_PLAN.md as tasks are completed.

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Step 4: Final Delivery

Goal: Push the code and open a Pull Request.

1. Action: The /build command's final phase usually covers this, or you can manually instruct the agent to finalize the project.

2. What Happens:

   • The agent runs final checks (linting/formatting).
   • It creates a README.md for the new application.
   • It commits all changes.
   • It pushes the feature branch to GitHub.
   • It uses the GitHub extension to Open a Pull Request.

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Summary of Commands

Step	Command	Input	Output
1. Spec	/techspec	Functional Doc (Drive)	Tech Spec (Drive)
2. Plan	/plan	Tech Spec (Drive)	IMPLEMENTATION_PLAN.md
3. Build	/build	Plan + Tech Spec	Code, Assets, App