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01 setup → Lesson 1

Chapter 01: Environment Setup

Understand why mise/bun/OpenRouter, then install and smoke-test each piece before scaffolding the project.

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Chapter 01: Environment Setup

Objective

Set up a reproducible local environment: mise (tool versions), bun (TypeScript runtime), and an OpenRouter API key so later chapters can call LLMs without reinventing setup.

Your tutor walks this gate by gate — one install, one verify — not one mega paste.

Concept: Why this stack

PieceJob
misePins runtimes/tools so “works on my machine” is a config file, not luck
bunFast TS runtime/package runner for the agent project
OpenRouterOne API key → many models; swap models with an env var

You are not installing “random tools.” You are making the rest of the course repeatable.

Concept check

Q1. Why pin tools with mise instead of “install whatever Node is on the laptop”?

Q2. What problem does OpenRouter solve compared to separate keys for every model vendor?

Concept answer key — attempt first

Answer key (concept)

Q1

Model answer: Reproducible versions across machines/sessions; the project declares what it needs.

Pass criteria: reproducibility / version pin

Q2

Model answer: One gateway/key; easy model swaps without re-plumbing auth.

Pass criteria: single key / multi-model routing

Gate: Install mise

curl https://mise.run | sh

Restart the terminal if needed. Verify:

mise --version

Stop if this fails.

Gate: Install bun via mise

mise use bun
bun --version

Pass: version string prints.

Gate: OpenRouter key + project dir

  1. Create a key at openrouter.ai/settings/keys
  2. Create the project:
mkdir weekend-coding-agent
cd weekend-coding-agent
  1. Env + gitignore:
echo 'OPENROUTER_API_KEY=sk-or-v1-your-key-here' > .env
echo 'AGENT_MODEL=google/gemini-3-pro-preview' >> .env
echo '.env' >> .gitignore

Never commit .env.

Optional model: anthropic/claude-opus-4.5.

  1. Lock tools:
# mise.toml
[tools]
bun = "latest"

Pass: ls shows .env, .gitignore, mise.toml; tutor confirms you did not paste the real key into chat.

What We Have Now

weekend-coding-agent/
├── .env              # OPENROUTER_API_KEY and AGENT_MODEL
├── .gitignore        # includes .env
└── mise.toml         # bun version locked

Later chapters build src/ step by step. Do not jump ahead until this gate is green.

Check your understanding

Q3. What is the smoke test for “bun is ready” in this lesson?

Q4. Why does the lesson put secrets in .env and force .gitignore before any agent code?

Answer key — attempt every question first

Answer key

Q3

Model answer: bun --version (after mise use) succeeds.

Pass criteria: version command

Q4

Model answer: Avoid committing API keys; separate config from code from the start.

Pass criteria: secrets hygiene

← Part 1 Index · Next: Chapter 02 →

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