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Developing with AI

Watch an AI implement a complete feature:

AI implementing a development tool 30-second teaser at 4x speed. The user mostly just confirms each phase.

This is Claude Code adding Bash development tools to devcontainer-toolbox. The AI:

  • Created the install script
  • Added VS Code extensions
  • Ran tests to verify everything works
  • Updated documentation

How? Three things made this possible: a cage, a plan, and tests.

1. The Cage: Keep AI Contained​

AI coding assistants can read files, write code, and run commands. You don't want them doing this on your main machine.

Run the AI inside a devcontainer.

┌─────────────────────────────────────────────────┐
│  Your Machine                                   │
│                                                 │
│  ┌───────────────────────────────────────────┐  │
│  │  Devcontainer (the cage)                  │  │
│  │                                           │  │
│  │  ┌─────────────────────────────────────┐  │  │
│  │  │  /workspace (your repo)             │  │  │
│  │  │  - AI can only see this folder      │  │  │
│  │  │  - All changes are visible to you   │  │  │
│  │  └─────────────────────────────────────┘  │  │
│  │                                           │  │
│  └───────────────────────────────────────────┘  │
│                                                 │
│  ~/Documents, ~/.ssh, ~/other-projects          │
│  (AI cannot access these)                       │
│                                                 │
└─────────────────────────────────────────────────┘

The devcontainer is isolated. It can't see your home directory, SSH keys, or other projects. If something goes wrong, rebuild and start fresh.

2. The Plan: Stop AI from Hallucinating​

Without guidance, AI assistants:

  • Jump straight into coding without understanding the scope
  • Invent file locations that don't exist
  • Create code that doesn't match your patterns
  • Forget steps mid-implementation

Make the AI create a plan first.

Instead of "implement feature X", say:

we need to create a plan for adding a new install script

The AI reads your documentation and creates a structured plan:

AI creating a plan

Notice what happens:

  1. AI reads your plan templates
  2. AI reads your code conventions
  3. AI creates a phased plan with specific tasks
  4. You review before any code is written

The plan is a markdown file. Edit it if something's wrong. Only after you approve does the AI start coding.

Why Plans Work

They reduce hallucinations. The AI follows your documented patterns instead of guessing.

They enable course correction. When something goes wrong, point to the plan. There's a shared reference.

They create documentation. Completed plans show what was implemented and why.

Learn more: Creating Plans

3. The Tests: AI Self-Correction​

Plans reduce errors but don't eliminate them. Tests catch what plans miss.

# AI runs tests after making changes
dev-test static install-dev-bash.sh

# Test failed: Missing SCRIPT_CATEGORY metadata
# AI: "I see the test failed. Let me add the missing metadata..."

When tests exist:

  1. The AI runs them after changes
  2. Failures tell the AI exactly what's wrong
  3. The AI fixes issues before you even see them

Tests turn the AI into a self-correcting system.

The Three Layers​

LayerWhat it does
DevcontainerIsolates AI to your repo - protects your machine
PlansGuides AI behavior - reduces hallucinations
TestsValidates AI output - catches mistakes automatically
  1. Cage it - Devcontainer limits what the AI can access
  2. Guide it - Plans keep the AI on track
  3. Verify it - Tests catch errors before you do

Getting Started​

1. Install Claude Code​

dev-setup
# Select "Claude Code" from AI & Machine Learning Tools

Or install directly:

.devcontainer/additions/install-dev-ai-claudecode.sh

2. Configure API Key​

Create the environment file:

mkdir -p .devcontainer.secrets/env-vars
echo "ANTHROPIC_API_KEY=your-api-key" > .devcontainer.secrets/env-vars/anthropic.env

3. Start Using It​

claude

Then tell it what you want to build. It will create a plan for your review.

Next Steps​