diff --git a/ai/backend-context.md b/ai/backend-context.md
index f3b5ddd..e7825fa 100644
--- a/ai/backend-context.md
+++ b/ai/backend-context.md
@@ -15,14 +15,11 @@ intentionally omitted here - update this section as entities land.
 
 - Look at similar entities for reference before writing anything new
 - Entities: constructor with properties, getters
-- DTOs: simple data containers for creation (e.g. `CreateElementDto`)
+- DTOs: simple data containers for creation (e.g. `CreateSetDto`)
 - Repositories: interfaces that define data access
   - Do not write unit tests for concrete repository implementations
     (e.g. `Postgres*Repository`). They are exercised by e2e tests.
     Use cases are tested with fake repositories.
-  - Repository methods that find records by a foreign key should accept
-    the related entity, not a raw id (e.g. `findBySet(Set $set)`, not
-    `findBySetId(int $setId)`).
 - Use cases: business logic with Request objects
   - When throwing exceptions, add `@throws` docblock
 - Fakes: in-memory implementations for testing
@@ -53,33 +50,16 @@ to be added to the repo; the Nix flake already provides
 Constructs LLMs default to that this project forbids. Name the trap
 explicitly so you catch yourself before writing it.
 
-- Arrow function:
-  - Forbidden: `fn ($node) => $node->getId()`
-  - Required: `function ($node) { return $node->getId(); }`
-- Inline FQCN type:
-  - Forbidden: `function f(): \Psr\Http\Message\ResponseInterface`
-  - Required: import `ResponseInterface`, then return `ResponseInterface`
-- Inline `::class`:
-  - Forbidden: `Container::get(\App\Foo\Bar::class)`
-  - Required: import `Bar`, then call `Container::get(Bar::class)`
-- Default param:
-  - Forbidden: `function f(int $count = 10)`
-  - Required: `function f(int $count)`
-- Default in fake:
-  - Forbidden: `public function create(Dto $dto, bool $strict = true)`
-  - Required: no default; every caller passes a value
-- Lookup returns stored ref:
-  - Forbidden: `return $this->items[$id] ?? null;`
-  - Required: rebuild a new instance with the stored fields
-- FK lookup by id:
-  - Forbidden: `findBySetId(int $setId)`
-  - Required: `findBySet(Set $set)`
-- Short variable name:
-  - Forbidden: one-letter or abbreviated names (`$t`, `$n`, `$res`)
-  - Required: explicit names (`$text`, `$node`, `$response`)
-- Em dash:
-  - Forbidden: comment or docblock containing an em dash character
-  - Required: use `-`
+| Anti-pattern | Forbidden | Required |
+|---|---|---|
+| Arrow function | `fn ($x) => $x->getId()` | `function ($x) { return $x->getId(); }` |
+| Inline FQCN type | `function f(): \Psr\Http\Message\ResponseInterface` | `use Psr\Http\Message\ResponseInterface;` then `function f(): ResponseInterface` |
+| Inline `::class` | `Container::get(\App\Foo\Bar::class)` | `use App\Foo\Bar;` then `Container::get(Bar::class)` |
+| Default param | `function f(int $count = 10)` | `function f(int $count)` |
+| Default in fake | `public function create(Dto $dto, bool $strict = true)` | no default; every caller passes a value |
+| Lookup returns stored ref | `return $this->items[$id] ?? null;` | rebuild a new instance with the stored fields |
+| Short variable name | `$t`, `$n`, `$res`, `$req`, `$e` | `$text`, `$node`, `$response`, `$request`, `$exception` |
+| Em dash | `// fetches user — by email` | `// fetches user - by email` |
 
 When generating code, scan the diff for these patterns before writing it
 to disk. If you catch one mid-write, rewrite that line.
diff --git a/ai/shared.md b/ai/shared.md
index 3d0522e..c07271e 100644
--- a/ai/shared.md
+++ b/ai/shared.md
@@ -16,9 +16,7 @@ guides (`backend-context.md`, `frontend-context.md`) extend these.
 4. Implement the code to make the test pass
 5. Run the test to confirm it passes
 6. Commit the implementation
-7. Repeat this red/green commit cycle for each new behavior. Do not
-   batch multiple behaviors into one failing-test commit and one
-   implementation commit when they can be reviewed separately.
+7. Repeat for each new behavior
 
 ## Code style
 
@@ -34,8 +32,8 @@ guides (`backend-context.md`, `frontend-context.md`) extend these.
   and fakes - if a helper accepts a value, every caller must supply it.
 - First, explore the codebase to understand existing patterns - look at similar
   files for reference before writing anything
-- Never use em dash characters in code, comments, or docblocks - use
-  hyphens (-) instead
+- Never use em dashes (—) in code, comments, or docblocks - use hyphens (-)
+  instead
 
 ## Git commit style
 
@@ -53,21 +51,9 @@ guides (`backend-context.md`, `frontend-context.md`) extend these.
 ## Git commits
 
 - Tests should be committed first, before implementation
-- Prefer small, reviewable commits. Commit each meaningful step as soon as
-  it is green and the pre-commit checklist passes.
 - One logical change per commit - a commit may span multiple files when they
   form a single logical unit (e.g. a use case with its request and exception,
   or a Vue SFC with its Pinia store and route entry)
-- Split commits by behavior, public contract, migration, wiring, docs, or
-  mechanical formatting when those parts can be reviewed independently.
-- A multi-file commit is okay only when the files form one inseparable
-  change. Do not use "one logical change" to justify batching adjacent work.
-- Do not batch several behaviors into one "tests" commit and one
-  "implementation" commit. Repeat the red/green cycle per behavior.
-- Do not bundle backend and frontend changes unless both are required for
-  the same user-facing behavior.
-- Do not bundle cleanup, refactors, renames, or formatting with feature
-  behavior.
 - Keep commits focused: not one file per commit, not unrelated work batched
 - Make commits frequent - commit each meaningful logical step as you go
 - Commits are for reviewing and documenting the development of code
@@ -97,8 +83,6 @@ mechanical, not aspirational - a "yes" to all is required.
 - [ ] On a feature branch (not master/main).
 - [ ] This commit is one logical change. If it spans unrelated changes,
       stop and split it.
-- [ ] This commit has been split as far as it can be while staying
-      reviewable. If any part can land independently, split it.
 - [ ] Tests for new behavior were committed BEFORE this implementation
       (or this commit IS the failing-test commit).
 
@@ -111,8 +95,6 @@ mechanical, not aspirational - a "yes" to all is required.
       (PHP or TS).
 - [ ] Find/lookup repository methods return new instances, not stored
       references.
-- [ ] Backend repository methods that find by a foreign key accept the
-      related entity, not a raw id.
 - [ ] No em dashes (use hyphens).
 - [ ] Variable names are explicit (no `$t`, `n`, `res`, `req`, `e`, etc.).
 - [ ] No `any` in TypeScript - use concrete types or `unknown` with a
diff --git a/backend/app/Element/CreateElementDto.php b/backend/app/Element/CreateElementDto.php
deleted file mode 100644
index db77dd7..0000000
--- a/backend/app/Element/CreateElementDto.php
+++ /dev/null
@@ -1,14 +0,0 @@
-<?php
-
-namespace App\Element;
-
-use App\Set\Set;
-
-class CreateElementDto
-{
-    public function __construct(
-        public Set $set,
-        public string $title,
-        public ?Element $parentElement,
-    ) {}
-}
diff --git a/backend/app/Element/Element.php b/backend/app/Element/Element.php
deleted file mode 100644
index 9ef75f6..0000000
--- a/backend/app/Element/Element.php
+++ /dev/null
@@ -1,35 +0,0 @@
-<?php
-
-namespace App\Element;
-
-use App\Set\Set;
-
-class Element
-{
-    public function __construct(
-        private int $id,
-        private string $title,
-        private Set $set,
-        private ?Element $parentElement,
-    ) {}
-
-    public function getId(): int
-    {
-        return $this->id;
-    }
-
-    public function getTitle(): string
-    {
-        return $this->title;
-    }
-
-    public function getSet(): Set
-    {
-        return $this->set;
-    }
-
-    public function getParentElement(): ?Element
-    {
-        return $this->parentElement;
-    }
-}
diff --git a/backend/app/Element/ElementModel.php b/backend/app/Element/ElementModel.php
deleted file mode 100644
index 119d287..0000000
--- a/backend/app/Element/ElementModel.php
+++ /dev/null
@@ -1,40 +0,0 @@
-<?php
-
-namespace App\Element;
-
-use Illuminate\Database\Eloquent\Builder;
-use Illuminate\Database\Eloquent\Model;
-
-/**
- * @property int $id
- * @property int $set_id
- * @property string $title
- * @property int|null $parent_element_id
- *
- * @method static Builder<static>|ElementModel newModelQuery()
- * @method static Builder<static>|ElementModel newQuery()
- * @method static Builder<static>|ElementModel query()
- * @method static Builder<static>|ElementModel whereId($value)
- * @method static Builder<static>|ElementModel whereParentElementId($value)
- * @method static Builder<static>|ElementModel whereSetId($value)
- * @method static Builder<static>|ElementModel whereTitle($value)
- *
- * @mixin \Eloquent
- */
-class ElementModel extends Model
-{
-    protected $table = 'elements';
-
-    public $timestamps = false;
-
-    protected $fillable = [
-        'set_id',
-        'title',
-        'parent_element_id',
-    ];
-
-    protected $casts = [
-        'set_id' => 'integer',
-        'parent_element_id' => 'integer',
-    ];
-}
diff --git a/backend/app/Element/ElementRepository.php b/backend/app/Element/ElementRepository.php
deleted file mode 100644
index 4f39fb6..0000000
--- a/backend/app/Element/ElementRepository.php
+++ /dev/null
@@ -1,17 +0,0 @@
-<?php
-
-namespace App\Element;
-
-use App\Set\Set as DomainSet;
-
-interface ElementRepository
-{
-    public function create(CreateElementDto $dto): Element;
-
-    public function find(int $id): ?Element;
-
-    /**
-     * @return Element[]
-     */
-    public function findBySet(DomainSet $set): array;
-}
diff --git a/backend/app/Element/EloquentElementRepository.php b/backend/app/Element/EloquentElementRepository.php
deleted file mode 100644
index 56ec2e6..0000000
--- a/backend/app/Element/EloquentElementRepository.php
+++ /dev/null
@@ -1,78 +0,0 @@
-<?php
-
-namespace App\Element;
-
-use App\Set\Set as DomainSet;
-use App\Set\SetRepository;
-use DomainException;
-
-class EloquentElementRepository implements ElementRepository
-{
-    public function __construct(private SetRepository $setRepo) {}
-
-    public function create(CreateElementDto $dto): Element
-    {
-        $model = ElementModel::create([
-            'set_id' => $dto->set->getId(),
-            'title' => $dto->title,
-            'parent_element_id' => $dto->parentElement?->getId(),
-        ]);
-
-        return new Element(
-            id: $model->id,
-            title: $dto->title,
-            set: $dto->set,
-            parentElement: $dto->parentElement,
-        );
-    }
-
-    public function find(int $id): ?Element
-    {
-        $model = ElementModel::find($id);
-
-        return $model === null ? null : $this->toDomain($model);
-    }
-
-    /**
-     * @return Element[]
-     */
-    public function findBySet(DomainSet $set): array
-    {
-        $models = ElementModel::where('set_id', $set->getId())
-            ->orderBy('id')
-            ->get();
-        $elements = [];
-        foreach ($models as $model) {
-            $elements[] = $this->toDomain($model);
-        }
-
-        return $elements;
-    }
-
-    private function toDomain(ElementModel $model): Element
-    {
-        $set = $this->setRepo->find($model->set_id);
-        if ($set === null) {
-            throw new DomainException(
-                "Set with id: {$model->set_id} doesnt exist"
-            );
-        }
-
-        $parentElement = null;
-        if ($model->parent_element_id !== null) {
-            $parentElement = $this->find($model->parent_element_id);
-            if ($parentElement === null) {
-                throw new DomainException(
-                    "Element with id: {$model->parent_element_id} doesnt exist"
-                );
-            }
-        }
-
-        return new Element(
-            id: $model->id,
-            title: $model->title,
-            set: $set,
-            parentElement: $parentElement,
-        );
-    }
-}
diff --git a/backend/app/Element/UseCases/CreateElement/CreateElement.php b/backend/app/Element/UseCases/CreateElement/CreateElement.php
deleted file mode 100644
index 6656338..0000000
--- a/backend/app/Element/UseCases/CreateElement/CreateElement.php
+++ /dev/null
@@ -1,85 +0,0 @@
-<?php
-
-namespace App\Element\UseCases\CreateElement;
-
-use App\Element\CreateElementDto;
-use App\Element\Element;
-use App\Element\ElementRepository;
-use App\Exceptions\BadRequestException;
-use App\Set\Set as DomainSet;
-use App\Set\SetRepository;
-use DomainException;
-
-class CreateElement
-{
-    public function __construct(
-        private ElementRepository $elementRepo,
-        private SetRepository $setRepo,
-    ) {}
-
-    /**
-     * @throws BadRequestException
-     * @throws DomainException
-     */
-    public function execute(CreateElementRequest $request): Element
-    {
-        if ($request->setId === null) {
-            throw new BadRequestException('setId is required');
-        }
-        if ($request->title === null || $request->title === '') {
-            throw new BadRequestException('title is required');
-        }
-
-        $set = $this->setRepo->find($request->setId);
-        if ($set === null) {
-            throw new DomainException(
-                "Set with id: {$request->setId} doesnt exist"
-            );
-        }
-
-        if ($request->parentElementId === null) {
-            $this->validateNoRootElementExists($set);
-
-            return $this->elementRepo->create(new CreateElementDto(
-                set: $set,
-                title: $request->title,
-                parentElement: null,
-            ));
-        }
-
-        $parentElement = $this->elementRepo->find(
-            $request->parentElementId
-        );
-        if ($parentElement === null) {
-            throw new DomainException(
-                "Element with id: {$request->parentElementId} doesnt exist"
-            );
-        }
-        if ($parentElement->getSet()->getId() !== $set->getId()) {
-            throw new DomainException(
-                'Parent element must belong to the same set'
-            );
-        }
-
-        return $this->elementRepo->create(new CreateElementDto(
-            set: $set,
-            title: $request->title,
-            parentElement: $parentElement,
-        ));
-    }
-
-    /**
-     * @throws DomainException
-     */
-    private function validateNoRootElementExists(DomainSet $set): void
-    {
-        $elements = $this->elementRepo->findBySet($set);
-        foreach ($elements as $element) {
-            if ($element->getParentElement() === null) {
-                throw new DomainException(
-                    'A root element already exists for this set'
-                );
-            }
-        }
-    }
-}
diff --git a/backend/app/Element/UseCases/CreateElement/CreateElementRequest.php b/backend/app/Element/UseCases/CreateElement/CreateElementRequest.php
deleted file mode 100644
index b9f0dbd..0000000
--- a/backend/app/Element/UseCases/CreateElement/CreateElementRequest.php
+++ /dev/null
@@ -1,12 +0,0 @@
-<?php
-
-namespace App\Element\UseCases\CreateElement;
-
-class CreateElementRequest
-{
-    public function __construct(
-        public ?int $setId,
-        public ?string $title,
-        public ?int $parentElementId,
-    ) {}
-}
diff --git a/backend/app/Providers/RepositoryServiceProvider.php b/backend/app/Providers/RepositoryServiceProvider.php
index 4b4b4f3..b4f42b2 100644
--- a/backend/app/Providers/RepositoryServiceProvider.php
+++ b/backend/app/Providers/RepositoryServiceProvider.php
@@ -4,10 +4,6 @@ namespace App\Providers;
 
 use App\Auth\EloquentSessionRepository;
 use App\Auth\SessionRepository;
-use App\Element\ElementRepository;
-use App\Element\EloquentElementRepository;
-use App\Set\EloquentSetRepository;
-use App\Set\SetRepository;
 use App\User\EloquentUserRepository;
 use App\User\UserRepository;
 use Illuminate\Support\ServiceProvider;
@@ -24,13 +20,5 @@ class RepositoryServiceProvider extends ServiceProvider
             SessionRepository::class,
             EloquentSessionRepository::class
         );
-        $this->app->bind(
-            SetRepository::class,
-            EloquentSetRepository::class
-        );
-        $this->app->bind(
-            ElementRepository::class,
-            EloquentElementRepository::class
-        );
     }
 }
diff --git a/backend/app/Set/CreateSetDto.php b/backend/app/Set/CreateSetDto.php
deleted file mode 100644
index 2999a88..0000000
--- a/backend/app/Set/CreateSetDto.php
+++ /dev/null
@@ -1,10 +0,0 @@
-<?php
-
-namespace App\Set;
-
-class CreateSetDto
-{
-    public function __construct(
-        public string $name,
-    ) {}
-}
diff --git a/backend/app/Set/EloquentSetRepository.php b/backend/app/Set/EloquentSetRepository.php
deleted file mode 100644
index ef8976e..0000000
--- a/backend/app/Set/EloquentSetRepository.php
+++ /dev/null
@@ -1,41 +0,0 @@
-<?php
-
-namespace App\Set;
-
-class EloquentSetRepository implements SetRepository
-{
-    public function create(CreateSetDto $dto): Set
-    {
-        $model = SetModel::create([
-            'name' => $dto->name,
-        ]);
-
-        return $this->toDomain($model);
-    }
-
-    public function find(int $id): ?Set
-    {
-        $model = SetModel::find($id);
-
-        return $model === null ? null : $this->toDomain($model);
-    }
-
-    public function getAll(): array
-    {
-        $models = SetModel::orderBy('id')->get();
-        $sets = [];
-        foreach ($models as $model) {
-            $sets[] = $this->toDomain($model);
-        }
-
-        return $sets;
-    }
-
-    private function toDomain(SetModel $model): Set
-    {
-        return new Set(
-            id: $model->id,
-            name: $model->name,
-        );
-    }
-}
diff --git a/backend/app/Set/Set.php b/backend/app/Set/Set.php
deleted file mode 100644
index d045e70..0000000
--- a/backend/app/Set/Set.php
+++ /dev/null
@@ -1,21 +0,0 @@
-<?php
-
-namespace App\Set;
-
-class Set
-{
-    public function __construct(
-        private int $id,
-        private string $name,
-    ) {}
-
-    public function getId(): int
-    {
-        return $this->id;
-    }
-
-    public function getName(): string
-    {
-        return $this->name;
-    }
-}
diff --git a/backend/app/Set/SetModel.php b/backend/app/Set/SetModel.php
deleted file mode 100644
index c30e2c9..0000000
--- a/backend/app/Set/SetModel.php
+++ /dev/null
@@ -1,27 +0,0 @@
-<?php
-
-namespace App\Set;
-
-use Illuminate\Database\Eloquent\Builder;
-use Illuminate\Database\Eloquent\Model;
-
-/**
- * @property int $id
- * @property string $name
- *
- * @method static Builder<static>|SetModel newModelQuery()
- * @method static Builder<static>|SetModel newQuery()
- * @method static Builder<static>|SetModel query()
- * @method static Builder<static>|SetModel whereId($value)
- * @method static Builder<static>|SetModel whereName($value)
- *
- * @mixin \Eloquent
- */
-class SetModel extends Model
-{
-    protected $table = 'sets';
-
-    public $timestamps = false;
-
-    protected $fillable = ['name'];
-}
diff --git a/backend/app/Set/SetRepository.php b/backend/app/Set/SetRepository.php
deleted file mode 100644
index 7f1efcd..0000000
--- a/backend/app/Set/SetRepository.php
+++ /dev/null
@@ -1,15 +0,0 @@
-<?php
-
-namespace App\Set;
-
-interface SetRepository
-{
-    public function create(CreateSetDto $dto): Set;
-
-    public function find(int $id): ?Set;
-
-    /**
-     * @return Set[]
-     */
-    public function getAll(): array;
-}
diff --git a/backend/database/migrations/2026_05_24_000000_sets_table.php b/backend/database/migrations/2026_05_24_000000_sets_table.php
deleted file mode 100644
index a39348b..0000000
--- a/backend/database/migrations/2026_05_24_000000_sets_table.php
+++ /dev/null
@@ -1,21 +0,0 @@
-<?php
-
-use Illuminate\Database\Migrations\Migration;
-use Illuminate\Database\Schema\Blueprint;
-use Illuminate\Support\Facades\Schema;
-
-return new class extends Migration
-{
-    public function up(): void
-    {
-        Schema::create('sets', function (Blueprint $table) {
-            $table->id();
-            $table->string('name');
-        });
-    }
-
-    public function down(): void
-    {
-        Schema::dropIfExists('sets');
-    }
-};
diff --git a/backend/database/migrations/2026_05_24_000001_elements_table.php b/backend/database/migrations/2026_05_24_000001_elements_table.php
deleted file mode 100644
index 377ba38..0000000
--- a/backend/database/migrations/2026_05_24_000001_elements_table.php
+++ /dev/null
@@ -1,25 +0,0 @@
-<?php
-
-use Illuminate\Database\Migrations\Migration;
-use Illuminate\Database\Schema\Blueprint;
-use Illuminate\Support\Facades\Schema;
-
-return new class extends Migration
-{
-    public function up(): void
-    {
-        Schema::create('elements', function (Blueprint $table) {
-            $table->id();
-            $table->foreignId('set_id')->constrained('sets');
-            $table->string('title');
-            $table->foreignId('parent_element_id')
-                ->nullable()
-                ->constrained('elements');
-        });
-    }
-
-    public function down(): void
-    {
-        Schema::dropIfExists('elements');
-    }
-};
diff --git a/backend/tests/Fakes/FakeElementRepository.php b/backend/tests/Fakes/FakeElementRepository.php
deleted file mode 100644
index 65dbcad..0000000
--- a/backend/tests/Fakes/FakeElementRepository.php
+++ /dev/null
@@ -1,69 +0,0 @@
-<?php
-
-namespace Tests\Fakes;
-
-use App\Element\CreateElementDto;
-use App\Element\Element;
-use App\Element\ElementRepository;
-use App\Set\Set as DomainSet;
-
-class FakeElementRepository implements ElementRepository
-{
-    /**
-     * @var Element[]
-     */
-    private array $elementsById = [];
-
-    public function create(CreateElementDto $dto): Element
-    {
-        $id = count($this->elementsById) + 1;
-        $element = new Element(
-            id: $id,
-            title: $dto->title,
-            set: $dto->set,
-            parentElement: $dto->parentElement,
-        );
-        $this->elementsById[$id] = $element;
-
-        return $element;
-    }
-
-    public function find(int $id): ?Element
-    {
-        if (! isset($this->elementsById[$id])) {
-            return null;
-        }
-
-        return $this->cloneElement($this->elementsById[$id]);
-    }
-
-    /**
-     * @return Element[]
-     */
-    public function findBySet(DomainSet $set): array
-    {
-        $elements = [];
-        foreach ($this->elementsById as $element) {
-            if ($element->getSet()->getId() === $set->getId()) {
-                $elements[] = $this->cloneElement($element);
-            }
-        }
-
-        return $elements;
-    }
-
-    private function cloneElement(Element $element): Element
-    {
-        $parentElement = $element->getParentElement();
-        if ($parentElement !== null) {
-            $parentElement = $this->cloneElement($parentElement);
-        }
-
-        return new Element(
-            id: $element->getId(),
-            title: $element->getTitle(),
-            set: $element->getSet(),
-            parentElement: $parentElement,
-        );
-    }
-}
diff --git a/backend/tests/Fakes/FakeSetRepository.php b/backend/tests/Fakes/FakeSetRepository.php
deleted file mode 100644
index 295e619..0000000
--- a/backend/tests/Fakes/FakeSetRepository.php
+++ /dev/null
@@ -1,57 +0,0 @@
-<?php
-
-namespace Tests\Fakes;
-
-use App\Set\CreateSetDto;
-use App\Set\Set as DomainSet;
-use App\Set\SetRepository;
-
-class FakeSetRepository implements SetRepository
-{
-    /**
-     * @var DomainSet[]
-     */
-    private array $setsById = [];
-
-    public function create(CreateSetDto $dto): DomainSet
-    {
-        $id = count($this->setsById) + 1;
-        $set = new DomainSet(
-            id: $id,
-            name: $dto->name,
-        );
-        $this->setsById[$id] = $set;
-
-        return $set;
-    }
-
-    public function find(int $id): ?DomainSet
-    {
-        if (! isset($this->setsById[$id])) {
-            return null;
-        }
-
-        return $this->cloneSet($this->setsById[$id]);
-    }
-
-    /**
-     * @return DomainSet[]
-     */
-    public function getAll(): array
-    {
-        $sets = [];
-        foreach ($this->setsById as $set) {
-            $sets[] = $this->cloneSet($set);
-        }
-
-        return $sets;
-    }
-
-    private function cloneSet(DomainSet $set): DomainSet
-    {
-        return new DomainSet(
-            id: $set->getId(),
-            name: $set->getName(),
-        );
-    }
-}
diff --git a/backend/tests/Unit/Element/ElementTest.php b/backend/tests/Unit/Element/ElementTest.php
deleted file mode 100644
index 3e914d9..0000000
--- a/backend/tests/Unit/Element/ElementTest.php
+++ /dev/null
@@ -1,33 +0,0 @@
-<?php
-
-namespace Tests\Unit\Element;
-
-use App\Element\Element;
-use App\Set\Set as DomainSet;
-use Tests\TestCase;
-
-class ElementTest extends TestCase
-{
-    public function testCreatesElementWithNullableParent(): void
-    {
-        $set = new DomainSet(1, 'Daily learning');
-        $rootElement = new Element(
-            id: 1,
-            title: 'Root',
-            set: $set,
-            parentElement: null,
-        );
-        $childElement = new Element(
-            id: 2,
-            title: 'Child',
-            set: $set,
-            parentElement: $rootElement,
-        );
-
-        $this->assertSame(2, $childElement->getId());
-        $this->assertSame('Child', $childElement->getTitle());
-        $this->assertSame($set, $childElement->getSet());
-        $this->assertSame($rootElement, $childElement->getParentElement());
-        $this->assertNull($rootElement->getParentElement());
-    }
-}
diff --git a/backend/tests/Unit/Element/UseCases/CreateElementTest.php b/backend/tests/Unit/Element/UseCases/CreateElementTest.php
deleted file mode 100644
index 2d01fc6..0000000
--- a/backend/tests/Unit/Element/UseCases/CreateElementTest.php
+++ /dev/null
@@ -1,183 +0,0 @@
-<?php
-
-namespace Tests\Unit\Element\UseCases;
-
-use App\Element\Element;
-use App\Element\UseCases\CreateElement\CreateElement;
-use App\Element\UseCases\CreateElement\CreateElementRequest;
-use App\Exceptions\BadRequestException;
-use App\Set\CreateSetDto;
-use DomainException;
-use Tests\Fakes\FakeElementRepository;
-use Tests\Fakes\FakeSetRepository;
-use Tests\TestCase;
-
-class CreateElementTest extends TestCase
-{
-    private FakeSetRepository $setRepo;
-
-    private FakeElementRepository $elementRepo;
-
-    private CreateElement $createElement;
-
-    protected function setUp(): void
-    {
-        $this->setRepo = new FakeSetRepository();
-        $this->elementRepo = new FakeElementRepository();
-        $this->createElement = new CreateElement(
-            $this->elementRepo,
-            $this->setRepo,
-        );
-    }
-
-    public function testCreatesRootElement(): void
-    {
-        $set = $this->setRepo->create(
-            new CreateSetDto('Daily learning')
-        );
-
-        $element = $this->createElement->execute(new CreateElementRequest(
-            setId: $set->getId(),
-            title: 'Root',
-            parentElementId: null,
-        ));
-
-        $this->assertInstanceOf(Element::class, $element);
-        $this->assertSame('Root', $element->getTitle());
-        $this->assertSame($set->getId(), $element->getSet()->getId());
-        $this->assertNull($element->getParentElement());
-    }
-
-    public function testCreatesChildElement(): void
-    {
-        $set = $this->setRepo->create(
-            new CreateSetDto('Daily learning')
-        );
-        $rootElement = $this->createElement->execute(
-            new CreateElementRequest(
-                setId: $set->getId(),
-                title: 'Root',
-                parentElementId: null,
-            )
-        );
-
-        $childElement = $this->createElement->execute(
-            new CreateElementRequest(
-                setId: $set->getId(),
-                title: 'Child',
-                parentElementId: $rootElement->getId(),
-            )
-        );
-
-        $this->assertSame('Child', $childElement->getTitle());
-        $this->assertSame(
-            $rootElement->getId(),
-            $childElement->getParentElement()->getId(),
-        );
-    }
-
-    public function testThrowsWhenSetIdMissing(): void
-    {
-        $this->expectException(BadRequestException::class);
-        $this->expectExceptionMessage('setId is required');
-
-        $this->createElement->execute(new CreateElementRequest(
-            setId: null,
-            title: 'Root',
-            parentElementId: null,
-        ));
-    }
-
-    public function testThrowsWhenTitleMissing(): void
-    {
-        $this->expectException(BadRequestException::class);
-        $this->expectExceptionMessage('title is required');
-
-        $this->createElement->execute(new CreateElementRequest(
-            setId: 1,
-            title: null,
-            parentElementId: null,
-        ));
-    }
-
-    public function testThrowsWhenSetDoesNotExist(): void
-    {
-        $this->expectException(DomainException::class);
-        $this->expectExceptionMessage('Set with id: 99 doesnt exist');
-
-        $this->createElement->execute(new CreateElementRequest(
-            setId: 99,
-            title: 'Root',
-            parentElementId: null,
-        ));
-    }
-
-    public function testThrowsWhenParentElementDoesNotExist(): void
-    {
-        $set = $this->setRepo->create(
-            new CreateSetDto('Daily learning')
-        );
-
-        $this->expectException(DomainException::class);
-        $this->expectExceptionMessage(
-            'Element with id: 99 doesnt exist'
-        );
-
-        $this->createElement->execute(new CreateElementRequest(
-            setId: $set->getId(),
-            title: 'Child',
-            parentElementId: 99,
-        ));
-    }
-
-    public function testThrowsWhenRootElementAlreadyExists(): void
-    {
-        $set = $this->setRepo->create(
-            new CreateSetDto('Daily learning')
-        );
-        $this->createElement->execute(new CreateElementRequest(
-            setId: $set->getId(),
-            title: 'Root',
-            parentElementId: null,
-        ));
-
-        $this->expectException(DomainException::class);
-        $this->expectExceptionMessage(
-            'A root element already exists for this set'
-        );
-
-        $this->createElement->execute(new CreateElementRequest(
-            setId: $set->getId(),
-            title: 'Another root',
-            parentElementId: null,
-        ));
-    }
-
-    public function testThrowsWhenParentBelongsToAnotherSet(): void
-    {
-        $parentSet = $this->setRepo->create(
-            new CreateSetDto('Parent set')
-        );
-        $childSet = $this->setRepo->create(
-            new CreateSetDto('Child set')
-        );
-        $parentElement = $this->createElement->execute(
-            new CreateElementRequest(
-                setId: $parentSet->getId(),
-                title: 'Parent root',
-                parentElementId: null,
-            )
-        );
-
-        $this->expectException(DomainException::class);
-        $this->expectExceptionMessage(
-            'Parent element must belong to the same set'
-        );
-
-        $this->createElement->execute(new CreateElementRequest(
-            setId: $childSet->getId(),
-            title: 'Invalid child',
-            parentElementId: $parentElement->getId(),
-        ));
-    }
-}
diff --git a/backend/tests/Unit/Set/SetTest.php b/backend/tests/Unit/Set/SetTest.php
deleted file mode 100644
index a98ac5f..0000000
--- a/backend/tests/Unit/Set/SetTest.php
+++ /dev/null
@@ -1,17 +0,0 @@
-<?php
-
-namespace Tests\Unit\Set;
-
-use App\Set\Set as DomainSet;
-use Tests\TestCase;
-
-class SetTest extends TestCase
-{
-    public function testCreatesSetWithName(): void
-    {
-        $set = new DomainSet(1, 'Daily learning');
-
-        $this->assertSame(1, $set->getId());
-        $this->assertSame('Daily learning', $set->getName());
-    }
-}