Claude’s Best Hidden Feature

Specs-Driven Development with Claude: A Detailed Breakdown

Key Concepts:

• Specs-Driven Development: A development approach that prioritizes detailed specifications before implementation.
• Claude (Anthropic): A large language model (LLM) used for generating and refining technical specifications.
• Ask User Question Tool (Claude Code): A specific tool within Claude Code designed to iteratively gather requirements and build specifications through a question-and-answer process.
• YOLO Mode (Claude Code): A mode allowing Claude to perform tasks without intermediate confirmation steps.
• Greenfield Project: A project starting from scratch with no existing codebase.
• Brownfield Project: A project involving modifications or additions to an existing codebase.
• REST API: Representational State Transfer Application Programming Interface – a standard way for different software systems to interact.
• Gemini API: Google's multimodal AI API.
• Plan Mode (Claude Code): A mode where Claude generates a detailed plan for implementation based on the specifications.

1. Introduction & The Problem of Spec Creation

The video addresses the challenge of creating detailed technical specifications for software projects, particularly for individuals without a technical background. While specs-driven development is widely recommended, the initial step of defining those specs can be daunting. The presenter introduces the "Ask User Question" tool within Claude Code (from Anthropic) as a solution to this problem.

2. Demonstrating the Tool: Text-to-Image Generator

The presenter demonstrates the tool's functionality using a practical example: building a text-to-image generator. The initial specification is deliberately simple: "Create a text to image generator. The user is going to provide text description and then we're going to use the Google Nano Banana REST API to generate four different images. The API does not support concurrent generation. So you will have to create or make multiple different calls. Do not use any SDK. Use the REST API." The presenter provides a link to the Nano Banana API documentation. This initial spec intentionally lacks technical details, focusing solely on the desired functionality.

3. The Iterative Questioning Process

The core of the tool's functionality lies in its iterative questioning process. Using the "Ask User Question" prompt (developed by Taric from the Claude Code team), Claude engages the user in a series of questions designed to clarify requirements and uncover potential issues. The presenter highlights that this process previously required manual sessions with LLMs like Opus or Sonnet, but the tool formalizes and streamlines it.

Examples of questions asked by Claude include:

• "When two of the four image generation fail, should the UI show partial results immediately or prompt the user to decide?"
• "Since the API doesn't support concurrent calls, how should the four sequential generation appear to the user during 20 to 40 seconds?"
• "Should the system enhance user prompt before sending it to the API or pass it verbatim?"
• "How should those four images should be generated in terms of the layout?"

The presenter emphasizes that these are the types of questions an engineer would typically ask, and the tool helps non-technical users consider these aspects. The user selects from predefined options for many questions, while others require free-text input (e.g., specifying "desktop only" for screen size). A total of 26 questions were asked in this example.

4. Generating Detailed Specifications

After the questioning phase, Claude generates a comprehensive specification document. This document includes:

• Architectural Details: Outlines the overall structure of the application.
• API Integrations: Specifies how the application will interact with the Nano Banana API.
• API Key Management: Details how the API key will be handled.
• User Interface (UI) Information: Describes the UI elements and their behavior.
• API Call Handling: Explains how API calls will be made and processed.
• File Structure: Suggests a project file structure.

The presenter recommends reviewing this document for completeness before proceeding.

5. Implementation & The "Plan Mode"

The presenter then demonstrates how to use Claude to implement the specifications. They switch to "Plan Mode" (activated by pressing Shift+Tab twice) to have Claude generate a detailed implementation plan. The plan outlines the creation of index.html and CSS files, details user management and data storage, and specifies the overall workflow. The presenter accepts the plan and allows Claude to begin implementation.

6. UI Refinement with Front-End Design Skills

The initial implementation includes a basic UI. The presenter utilizes a Chrome extension for Claude to analyze the webpage and suggest UI improvements, leveraging Claude’s front-end design capabilities. Claude transforms the basic design into a more visually appealing interface, including pre-built prompt templates. The presenter notes that Claude’s front-end skills are comparable to Gemini 3.

7. Results & Iteration

The resulting application is fully functional. The presenter notes a minor issue with a grainy effect on the images, suggesting a simple iteration with Claude to resolve it. A full-resolution downloaded image is shown to demonstrate the quality of the generated images.

8. Applying the Tool to Brownfield Projects

The presenter demonstrates the tool's applicability to existing codebases ("brownfield projects"). They create a new specification to implement dark mode in an existing application, prompting Claude to help with the process. Claude asks 23 questions related to dark mode implementation, highlighting the tool's ability to address even seemingly simple changes with detailed technical considerations. The presenter then instructs Claude to implement the dark mode within the existing codebase.

9. Learning & Skill Development

The presenter emphasizes that the tool is not only useful for generating specifications but also for learning. Even for individuals with some technical skills (e.g., data science or backend development), the tool can expose them to different options and best practices in areas where they lack expertise (e.g., front-end development).

10. Conclusion & Call to Action

The video concludes by encouraging viewers to try the tool and share their experiences and preferred specification-building methods in the comments. The presenter highlights the potential of Claude Code's "Ask User Question" tool to bridge the gap between non-technical ideas and detailed technical specifications, ultimately leading to more efficient and well-designed software projects.

Data & Statistics:

• The tool asked a total of 26 questions for the text-to-image generator example.
• The tool asked 23 questions for the dark mode implementation example.
• The presenter states Claude’s front-end design skills are “on par with Gemini 3.”

Technical Terms Explained:

• LLM (Large Language Model): A type of artificial intelligence that can understand and generate human-like text.
• API (Application Programming Interface): A set of rules and specifications that allow different software applications to communicate with each other.
• SDK (Software Development Kit): A collection of software development tools in one installable package.
• REST (Representational State Transfer): An architectural style for designing networked applications.
• UI (User Interface): The means by which the user interacts with a software application.