Scaffold Exercises

# Scaffold Exercises

Create exercise directory structures that pass `pnpm ai-hero-cli internal lint`, then commit with `git commit`.

## Directory naming

- **Sections**: `XX-section-name/` inside `exercises/` (e.g., `01-retrieval-skill-building`) - **Exercises**: `XX.YY-exercise-name/` inside a section (e.g., `01.03-retrieval-with-bm25`) - Section number = `XX`, exercise number = `XX.YY` - Names are dash-case (lowercase, hyphens)

## Exercise variants

Each exercise needs at least one of these subfolders:

- `problem/` - student workspace with TODOs - `solution/` - reference implementation - `explainer/` - conceptual material, no TODOs

When stubbing, default to `explainer/` unless the plan specifies otherwise.

## Required files

Each subfolder (`problem/`, `solution/`, `explainer/`) needs a `readme.md` that:

- Is **not empty** (must have real content, even a single title line works) - Has no broken links

When stubbing, create a minimal readme with a title and a description:

```md # Exercise Title

Description here ```

If the subfolder has code, it also needs a `main.ts` (>1 line). But for stubs, a readme-only exercise is fine.

## Workflow

1. **Parse the plan** - extract section names, exercise names, and variant types 2. **Create directories** - `mkdir -p` for each path 3. **Create stub readmes** - one `readme.md` per variant folder with a title 4. **Run lint** - `pnpm ai-hero-cli internal lint` to validate 5. **Fix any errors** - iterate until lint passes

## Lint rules summary

The linter (`pnpm ai-hero-cli internal lint`) checks:

- Each exercise has subfolders (`problem/`, `solution/`, `explainer/`) - At least one of `problem/`, `explainer/`, or `explainer.1/` exists - `readme.md` exists and is non-empty in the primary subfolder - No `.gitkeep` files - No `speaker-notes.md` files - No broken links in readmes - No `pnpm run exercise` commands in readmes - `main.ts` required per subfolder unless it's readme-only

## Moving/renaming exercises

When renumbering or moving exercises:

1. Use `git mv` (not `mv`) to rename directories - preserves git history 2. Update the numeric prefix to maintain order 3. Re-run lint after moves

Example:

```bash git mv exercises/01-retrieval/01.03-embeddings exercises/01-retrieval/01.04-embeddings ```

## Example: stubbing from a plan

Given a plan like:

``` Section 05: Memory Skill Building - 05.01 Introduction to Memory - 05.02 Short-term Memory (explainer + problem + solution) - 05.03 Long-term Memory ```

Create:

```bash mkdir -p exercises/05-memory-skill-building/05.01-introduction-to-memory/explainer mkdir -p exercises/05-memory-skill-building/05.02-short-term-memory/{explainer,problem,solution} mkdir -p exercises/05-memory-skill-building/05.03-long-term-memory/explainer ```

Then create readme stubs:

``` exercises/05-memory-skill-building/05.01-introduction-to-memory/explainer/readme.md -> "# Introduction to Memory" exercises/05-memory-skill-building/05.02-short-term-memory/explainer/readme.md -> "# Short-term Memory" exercises/05-memory-skill-building/05.02-short-term-memory/problem/readme.md -> "# Short-term Memory" exercises/05-memory-skill-building/05.02-short-term-memory/solution/readme.md -> "# Short-term Memory" exercises/05-memory-skill-building/05.03-long-term-memory/explainer/readme.md -> "# Long-term Memory" ```