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What We've Built

Interactive Neural Network Visualizer

Try the demo →

A fully functional web application that lets you step through neural network training on the XOR problem. This isn't just a static visualization - it's an interactive learning tool that shows every detail of the training process.

Features

  • Step-by-step training: Move forward/backward through training iterations
  • Network visualization: See the architecture with real-time weight updates
  • Forward pass breakdown: Mathematical notation showing each computation
  • Backward pass detail: Gradient calculations with the chain rule made explicit
  • Loss tracking: Watch how error decreases over training
  • Interactive controls: Play, pause, reset, adjust learning rate, add noise

Technical Implementation

Built with React 18 + TypeScript + Vite:

  • Pure TypeScript neural network (no ML libraries)
  • KaTeX for mathematical notation rendering
  • SVG-based network visualization
  • Fully client-side - runs entirely in browser
  • Comprehensive test suite with Vitest

Why it matters: Understanding backpropagation is fundamental to understanding how any neural network (including transformers) learns. This visualizer makes the abstract math concrete and interactive.

Python Neural Network Implementation

Location: src/network.py

A from-scratch implementation of a feedforward neural network in pure NumPy:

  • Forward and backward pass with detailed intermediate values
  • Sigmoid activation and binary cross-entropy loss
  • Configurable architecture (layers, neurons, learning rate)
  • Training history tracking for analysis
  • Visualization utilities using matplotlib

Tests: Comprehensive pytest suite in tests/test_network.py

Why it matters: Implementing backprop by hand (no PyTorch/TensorFlow magic) forces you to understand exactly what's happening at each step.

Development Infrastructure

Test-Driven Development Workflow

All code in this project follows TDD:

  • RED: Write failing test that defines desired behavior
  • GREEN: Implement minimal code to pass
  • REFACTOR: Improve with safety net of passing tests

Example: The web visualizer's Network class has 100% test coverage before any UI was built.

Custom Claude Code Commands

16 custom commands for streamlined development:

  • /hygiene - Quick project health check
  • /commit - Atomic commits with quality checks
  • /tdd - TDD workflow guidance
  • /docs - Documentation maintenance
  • /next - AI-recommended priorities

See all commands →

Claude Code Agents

Specialized agents for analysis tasks:

  • documentation-auditor - Ensures docs quality
  • session-insights - Analyzes development patterns
  • next-priorities - Recommends what to work on
  • test-coverage-advisor - Identifies testing gaps

Learn about agents →

Token Efficiency Optimization

Through npm script delegation and command optimization:

  • 87-91% token reduction in common operations
  • Fast command execution (< 1 second for most)
  • Consistent, reliable results

Read more →

Python Tooling

Visualization Utilities

Location: src/visualize.py

Functions for analyzing and visualizing neural network training:

  • plot_training() - Loss curves and weight evolution
  • draw_network() - Network graph with weights/gradients
  • draw_training_steps() - Network state at key milestones
  • plot_biases() - Bias evolution through training

Testing Infrastructure

  • Python: pytest with coverage tracking
  • TypeScript: Vitest for unit and integration tests
  • CI/CD: GitHub Actions for automated testing

Documentation

Project Documentation

  • README.md - Project overview and goals
  • PLAN.md - Detailed design for web visualizer
  • LEARNINGS.md - Captured insights and patterns
  • AGENTS.md - Guide to commands vs agents

Development Guides

12 comprehensive guides covering:

  • TDD with Claude Code
  • Best practices for AI-assisted development
  • Token efficiency patterns
  • Command and agent patterns
  • Self-updating documentation

Browse development docs →

What This Enables

With these foundations in place, we can:

  1. Experiment rapidly - TDD and testing infrastructure catch regressions
  2. Visualize concepts - Interactive tools make abstract ideas concrete
  3. Document learnings - Custom commands make it easy to capture insights
  4. Build incrementally - Each piece builds on tested, working code

Source Code

All code is open source and available on GitHub:

Repository: github.com/jflournoy/llm-workings

  • src/ - Python neural network implementation
  • web/ - Interactive web visualizer
  • tests/ - Python test suite
  • .claude/ - Custom commands and agents
  • docs/ - This documentation site

Next Steps

Now that we have working tools and visualizations, what comes next?

See the roadmap →

A hands-on learning project exploring LLM internals