Implement character and scenario management features in the API

- Add create, update, and delete functionality for characters and scenarios in CharacterService and ScenarioService.
- Introduce CreateCharacterRequest and CreateScenarioRequest models for handling character and scenario creation requests.
- Update CharactersResource and ScenariosResource to expose new endpoints for character and scenario management.
- Enhance OpenAPI specification to document new API endpoints and request/response schemas.
- Implement frontend components for managing characters and scenarios, including listing, creating, editing, and deleting.
- Add unit tests for CharacterService to ensure correct behavior of character creation and updates.

src/main/java/de/neitzel/roleplay/business/CharacterService.java

@@ -3,6 +3,7 @@ package de.neitzel.roleplay.business;
 import de.neitzel.roleplay.data.CharacterEntity;
 import de.neitzel.roleplay.data.CharacterRepository;
 import de.neitzel.roleplay.fascade.model.CharacterDefinition;
+import de.neitzel.roleplay.fascade.model.CreateCharacterRequest;
 
 import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.inject.Inject;
@@ -47,6 +48,73 @@ public class CharacterService {
         return entity != null ? Optional.of(toCharacterDefinition(entity)) : Optional.empty();
     }
 
+    /**
+     * Creates a new character from the request. Uses request id if present, otherwise generates a UUID.
+     *
+     * @param request the create request (name and role required)
+     * @return the created character definition
+     */
+    public CharacterDefinition create(final CreateCharacterRequest request) {
+        CharacterEntity entity = fromRequest(request, request.getId() != null ? request.getId() : UUID.randomUUID());
+        characterRepository.persist(entity);
+        return toCharacterDefinition(entity);
+    }
+
+    /**
+     * Updates an existing character by id. Full replace of all fields.
+     *
+     * @param id      the character UUID
+     * @param request the update request
+     * @return the updated character definition
+     * @throws java.util.NoSuchElementException if the character does not exist
+     */
+    public CharacterDefinition update(final UUID id, final CreateCharacterRequest request) {
+        CharacterEntity entity = characterRepository.findByIdOptional(id);
+        if (entity == null) {
+            throw new java.util.NoSuchElementException("No character found with id: " + id);
+        }
+        applyRequest(entity, request);
+        characterRepository.persist(entity);
+        return toCharacterDefinition(entity);
+    }
+
+    /**
+     * Deletes a character by id.
+     *
+     * @param id the character UUID
+     * @return true if deleted, false if no character existed
+     */
+    public boolean delete(final UUID id) {
+        CharacterEntity entity = characterRepository.findByIdOptional(id);
+        if (entity == null) {
+            return false;
+        }
+        characterRepository.delete(entity);
+        return true;
+    }
+
+    /**
+     * Builds a new entity from the request and the given id.
+     */
+    private static CharacterEntity fromRequest(final CreateCharacterRequest request, final UUID id) {
+        CharacterEntity entity = new CharacterEntity();
+        entity.setId(id);
+        applyRequest(entity, request);
+        return entity;
+    }
+
+    /**
+     * Applies request fields to an existing entity (id is not changed).
+     */
+    private static void applyRequest(final CharacterEntity entity, final CreateCharacterRequest request) {
+        entity.setName(request.getName());
+        entity.setRole(request.getRole());
+        entity.setBackstory(request.getBackstory());
+        entity.setSpeakingStyle(request.getSpeakingStyle());
+        entity.setPersonalityTraits(request.getPersonalityTraits() != null ? request.getPersonalityTraits() : List.of());
+        entity.setGoals(request.getGoals() != null ? request.getGoals() : List.of());
+    }
+
     /**
      * Maps a character entity to the API CharacterDefinition. Uses entity id as string for API id.
      */

src/main/java/de/neitzel/roleplay/business/ScenarioService.java

@@ -1,14 +1,18 @@
 package de.neitzel.roleplay.business;
 
+import de.neitzel.roleplay.data.CharacterRepository;
 import de.neitzel.roleplay.data.ScenarioCharacterEntity;
 import de.neitzel.roleplay.data.ScenarioEntity;
 import de.neitzel.roleplay.data.ScenarioRepository;
 import de.neitzel.roleplay.fascade.model.CharacterDefinition;
+import de.neitzel.roleplay.fascade.model.CreateScenarioRequest;
+import de.neitzel.roleplay.fascade.model.ScenarioCharacterSlot;
 import de.neitzel.roleplay.fascade.model.ScenarioSetup;
 import de.neitzel.roleplay.fascade.model.ScenarioSummary;
 
 import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.inject.Inject;
+import jakarta.persistence.EntityManager;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -22,10 +26,15 @@ import java.util.UUID;
 public class ScenarioService {
 
     private final ScenarioRepository scenarioRepository;
+    private final CharacterRepository characterRepository;
+    private final EntityManager entityManager;
 
     @Inject
-    public ScenarioService(final ScenarioRepository scenarioRepository) {
+    public ScenarioService(final ScenarioRepository scenarioRepository, final CharacterRepository characterRepository,
+            final EntityManager entityManager) {
         this.scenarioRepository = scenarioRepository;
+        this.characterRepository = characterRepository;
+        this.entityManager = entityManager;
     }
 
     /**
@@ -50,6 +59,97 @@ public class ScenarioService {
         return entity != null ? Optional.of(toScenarioSetup(entity)) : Optional.empty();
     }
 
+    /**
+     * Creates a new scenario from the request. Validates that all referenced characters exist.
+     *
+     * @param request the create request (name required; optional setting, initialConflict, characterSlots)
+     * @return the created scenario summary
+     * @throws IllegalArgumentException if any referenced character id is not found
+     */
+    public ScenarioSummary create(final CreateScenarioRequest request) {
+        UUID scenarioId = UUID.randomUUID();
+        ScenarioEntity scenario = new ScenarioEntity();
+        scenario.setId(scenarioId);
+        scenario.setName(request.getName());
+        scenario.setSetting(request.getSetting());
+        scenario.setInitialConflict(request.getInitialConflict());
+        List<ScenarioCharacterSlot> slots = request.getCharacterSlots() != null ? request.getCharacterSlots() : List.of();
+        for (ScenarioCharacterSlot slot : slots) {
+            var character = characterRepository.findByIdOptional(slot.getCharacterId());
+            if (character == null) {
+                throw new IllegalArgumentException("Character not found: " + slot.getCharacterId());
+            }
+            ScenarioCharacterEntity link = new ScenarioCharacterEntity();
+            link.setId(UUID.randomUUID());
+            link.setScenario(scenario);
+            link.setCharacter(character);
+            link.setUserCharacter(Boolean.TRUE.equals(slot.getIsUserCharacter()));
+            link.setPosition(slot.getPosition() != null ? slot.getPosition() : 0);
+            scenario.getScenarioCharacters().add(link);
+        }
+        scenarioRepository.persist(scenario);
+        for (ScenarioCharacterEntity link : scenario.getScenarioCharacters()) {
+            entityManager.persist(link);
+        }
+        entityManager.flush();
+        return toScenarioSummary(scenario);
+    }
+
+    /**
+     * Updates an existing scenario by id. Full replace; replaces all character slots.
+     *
+     * @param id      the scenario UUID
+     * @param request the update request
+     * @return the updated scenario summary
+     * @throws java.util.NoSuchElementException if the scenario does not exist
+     * @throws IllegalArgumentException        if any referenced character id is not found
+     */
+    public ScenarioSummary update(final UUID id, final CreateScenarioRequest request) {
+        ScenarioEntity scenario = scenarioRepository.findByIdWithCharacters(id);
+        if (scenario == null) {
+            throw new java.util.NoSuchElementException("No scenario found with id: " + id);
+        }
+        scenario.setName(request.getName());
+        scenario.setSetting(request.getSetting());
+        scenario.setInitialConflict(request.getInitialConflict());
+        scenario.getScenarioCharacters().clear();
+        List<ScenarioCharacterSlot> slots = request.getCharacterSlots() != null ? request.getCharacterSlots() : List.of();
+        for (ScenarioCharacterSlot slot : slots) {
+            var character = characterRepository.findByIdOptional(slot.getCharacterId());
+            if (character == null) {
+                throw new IllegalArgumentException("Character not found: " + slot.getCharacterId());
+            }
+            ScenarioCharacterEntity link = new ScenarioCharacterEntity();
+            link.setId(UUID.randomUUID());
+            link.setScenario(scenario);
+            link.setCharacter(character);
+            link.setUserCharacter(Boolean.TRUE.equals(slot.getIsUserCharacter()));
+            link.setPosition(slot.getPosition() != null ? slot.getPosition() : 0);
+            scenario.getScenarioCharacters().add(link);
+        }
+        scenarioRepository.persist(scenario);
+        for (ScenarioCharacterEntity link : scenario.getScenarioCharacters()) {
+            entityManager.persist(link);
+        }
+        entityManager.flush();
+        return toScenarioSummary(scenario);
+    }
+
+    /**
+     * Deletes a scenario by id. Cascades to scenario-character links.
+     *
+     * @param id the scenario UUID
+     * @return true if deleted, false if no scenario existed
+     */
+    public boolean delete(final UUID id) {
+        ScenarioEntity scenario = scenarioRepository.findByIdWithCharacters(id);
+        if (scenario == null) {
+            return false;
+        }
+        scenarioRepository.delete(scenario);
+        return true;
+    }
+
     /**
      * Maps a scenario entity to the list-summary DTO.
      */

src/main/java/de/neitzel/roleplay/data/ScenarioEntity.java

@@ -35,7 +35,7 @@ public class ScenarioEntity extends PanacheEntityBase {
     private String initialConflict;
 
     @OneToMany(mappedBy = "scenario", cascade = CascadeType.ALL, orphanRemoval = true)
-    @OrderBy("isUserCharacter DESC, position ASC")
+    @OrderBy("userCharacter DESC, position ASC")
     private List<ScenarioCharacterEntity> scenarioCharacters = new ArrayList<>();
 
     /**
@@ -102,15 +102,19 @@ public class ScenarioEntity extends PanacheEntityBase {
 
     /**
      * Returns the list of scenario–character links (user character first, then AI by position).
+     * Never returns null; scenarios loaded from DB without characters (e.g. seed data) get an empty list.
      */
     public List<ScenarioCharacterEntity> getScenarioCharacters() {
+        if (scenarioCharacters == null) {
+            scenarioCharacters = new ArrayList<>();
+        }
         return scenarioCharacters;
     }
 
     /**
-     * Sets the list of scenario–character links.
+     * Sets the list of scenario–character links. Null is treated as empty list.
      */
     public void setScenarioCharacters(final List<ScenarioCharacterEntity> scenarioCharacters) {
-        this.scenarioCharacters = scenarioCharacters;
+        this.scenarioCharacters = scenarioCharacters != null ? scenarioCharacters : new ArrayList<>();
     }
 }

src/main/java/de/neitzel/roleplay/fascade/CharactersResource.java

@@ -3,12 +3,14 @@ package de.neitzel.roleplay.fascade;
 import de.neitzel.roleplay.business.CharacterService;
 import de.neitzel.roleplay.fascade.model.CharacterDefinition;
 import de.neitzel.roleplay.fascade.model.CharacterListResponse;
+import de.neitzel.roleplay.fascade.model.CreateCharacterRequest;
 import de.neitzel.roleplay.generated.api.CharactersApi;
 
 import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.inject.Inject;
 import jakarta.ws.rs.NotFoundException;
 
+import java.util.NoSuchElementException;
 import java.util.UUID;
 
 /**
@@ -36,4 +38,26 @@ public class CharactersResource implements CharactersApi {
         return characterService.getCharacter(characterId)
                 .orElseThrow(() -> new NotFoundException("No character found with id: " + characterId));
     }
+
+    @Override
+    public CharacterDefinition createCharacter(final CreateCharacterRequest createCharacterRequest) {
+        return characterService.create(createCharacterRequest);
+    }
+
+    @Override
+    public CharacterDefinition updateCharacter(final UUID characterId,
+            final CreateCharacterRequest createCharacterRequest) {
+        try {
+            return characterService.update(characterId, createCharacterRequest);
+        } catch (final NoSuchElementException e) {
+            throw new NotFoundException("No character found with id: " + characterId);
+        }
+    }
+
+    @Override
+    public void deleteCharacter(final UUID characterId) {
+        if (!characterService.delete(characterId)) {
+            throw new NotFoundException("No character found with id: " + characterId);
+        }
+    }
 }

src/main/java/de/neitzel/roleplay/fascade/ScenariosResource.java

@@ -1,14 +1,18 @@
 package de.neitzel.roleplay.fascade;
 
 import de.neitzel.roleplay.business.ScenarioService;
+import de.neitzel.roleplay.fascade.model.CreateScenarioRequest;
 import de.neitzel.roleplay.fascade.model.ScenarioListResponse;
 import de.neitzel.roleplay.fascade.model.ScenarioSetup;
+import de.neitzel.roleplay.fascade.model.ScenarioSummary;
 import de.neitzel.roleplay.generated.api.ScenariosApi;
 
 import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.inject.Inject;
+import jakarta.ws.rs.BadRequestException;
 import jakarta.ws.rs.NotFoundException;
 
+import java.util.NoSuchElementException;
 import java.util.UUID;
 
 /**
@@ -36,4 +40,32 @@ public class ScenariosResource implements ScenariosApi {
         return scenarioService.getScenarioAsSetup(scenarioId)
                 .orElseThrow(() -> new NotFoundException("No scenario found with id: " + scenarioId));
     }
+
+    @Override
+    public ScenarioSummary createScenario(final CreateScenarioRequest createScenarioRequest) {
+        try {
+            return scenarioService.create(createScenarioRequest);
+        } catch (final IllegalArgumentException e) {
+            throw new BadRequestException(e.getMessage());
+        }
+    }
+
+    @Override
+    public ScenarioSummary updateScenario(final UUID scenarioId,
+            final CreateScenarioRequest createScenarioRequest) {
+        try {
+            return scenarioService.update(scenarioId, createScenarioRequest);
+        } catch (final NoSuchElementException e) {
+            throw new NotFoundException("No scenario found with id: " + scenarioId);
+        } catch (final IllegalArgumentException e) {
+            throw new BadRequestException(e.getMessage());
+        }
+    }
+
+    @Override
+    public void deleteScenario(final UUID scenarioId) {
+        if (!scenarioService.delete(scenarioId)) {
+            throw new NotFoundException("No scenario found with id: " + scenarioId);
+        }
+    }
 }

src/main/resources/application.yml

@@ -1,9 +1,6 @@
 quarkus:
   application:
     name: roleplay
-  resteasy-reactive:
-    scan:
-      paths: de.neitzel.roleplay.fascade,de.neitzel.roleplay.business,de.neitzel.roleplay.common,de.neitzel.roleplay.data
   http:
     root-path: /
   datasource:
@@ -12,9 +9,6 @@ quarkus:
       url: jdbc:h2:mem:roleplay;DB_CLOSE_DELAY=-1
     username: sa
     password: ""
-  hibernate-orm:
-    database:
-      generation: none
   liquibase:
     change-log: db/migration/changelog.xml
     migrate-at-start: true

src/main/resources/openapi-roleplay-public-v1.yml

@@ -61,6 +61,31 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/ScenarioListResponse'
+    post:
+      operationId: createScenario
+      summary: Create a scenario
+      description: Creates a new scenario with optional character slots. Server generates UUID.
+      tags:
+        - scenarios
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/CreateScenarioRequest'
+      responses:
+        "201":
+          description: Scenario created.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ScenarioSummary'
+        "400":
+          description: Invalid request body or referenced character not found.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorResponse'
 
   /scenarios/{scenarioId}:
     get:
@@ -84,6 +109,56 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/ErrorResponse'
+    put:
+      operationId: updateScenario
+      summary: Update a scenario
+      description: Full replace. Replaces all character slots.
+      tags:
+        - scenarios
+      parameters:
+        - $ref: '#/components/parameters/ScenarioId'
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/CreateScenarioRequest'
+      responses:
+        "200":
+          description: Scenario updated.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ScenarioSummary'
+        "400":
+          description: Invalid request body or referenced character not found.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorResponse'
+        "404":
+          description: Scenario not found.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorResponse'
+    delete:
+      operationId: deleteScenario
+      summary: Delete a scenario
+      description: Removes the scenario template.
+      tags:
+        - scenarios
+      parameters:
+        - $ref: '#/components/parameters/ScenarioId'
+      responses:
+        "204":
+          description: Scenario deleted.
+        "404":
+          description: Scenario not found.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorResponse'
 
   /characters:
     get:
@@ -99,6 +174,31 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/CharacterListResponse'
+    post:
+      operationId: createCharacter
+      summary: Create a character
+      description: Creates a new character template. Server generates UUID if id is omitted.
+      tags:
+        - characters
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/CreateCharacterRequest'
+      responses:
+        "201":
+          description: Character created.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/CharacterDefinition'
+        "400":
+          description: Invalid request body.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorResponse'
 
   /characters/{characterId}:
     get:
@@ -122,6 +222,56 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/ErrorResponse'
+    put:
+      operationId: updateCharacter
+      summary: Update a character
+      description: Full replace of the character. All fields required except optional ones.
+      tags:
+        - characters
+      parameters:
+        - $ref: '#/components/parameters/CharacterId'
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/CreateCharacterRequest'
+      responses:
+        "200":
+          description: Character updated.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/CharacterDefinition'
+        "400":
+          description: Invalid request body.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorResponse'
+        "404":
+          description: Character not found.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorResponse'
+    delete:
+      operationId: deleteCharacter
+      summary: Delete a character
+      description: Removes the character template. Scenarios referencing it may need updating.
+      tags:
+        - characters
+      parameters:
+        - $ref: '#/components/parameters/CharacterId'
+      responses:
+        "204":
+          description: Character deleted.
+        "404":
+          description: Character not found.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ErrorResponse'
 
   /sessions:
     post:
@@ -401,6 +551,80 @@ components:
       required:
         - characters
 
+    CreateCharacterRequest:
+      type: object
+      description: Request body for creating or updating a character. id optional on create (server generates UUID).
+      properties:
+        id:
+          type: string
+          format: uuid
+          description: Optional on create; server generates if omitted.
+        name:
+          type: string
+          description: Display name.
+        role:
+          type: string
+          description: Narrative role.
+        backstory:
+          type: string
+          description: Character background.
+        speakingStyle:
+          type: string
+          description: How the character speaks.
+        personalityTraits:
+          type: array
+          items:
+            type: string
+          description: List of personality traits.
+        goals:
+          type: array
+          items:
+            type: string
+          description: Character goals.
+      required:
+        - name
+        - role
+
+    ScenarioCharacterSlot:
+      type: object
+      description: Assignment of a character to a scenario slot (user or AI, with position).
+      properties:
+        characterId:
+          type: string
+          format: uuid
+          description: Reference to a saved character.
+        isUserCharacter:
+          type: boolean
+          description: True if this slot is the player character.
+        position:
+          type: integer
+          description: Order of the character (0 for user, 1+ for AI).
+      required:
+        - characterId
+        - isUserCharacter
+        - position
+
+    CreateScenarioRequest:
+      type: object
+      description: Request body for creating or updating a scenario.
+      properties:
+        name:
+          type: string
+          description: Human-readable scenario name.
+        setting:
+          type: string
+          description: Place, time, and atmosphere.
+        initialConflict:
+          type: string
+          description: The hook or starting conflict.
+        characterSlots:
+          type: array
+          items:
+            $ref: '#/components/schemas/ScenarioCharacterSlot'
+          description: Assigned characters (one user, ordered AI).
+      required:
+        - name
+
     ScenarioSetup:
       type: object
       description: |

src/main/web/src/App.tsx

@@ -1,17 +1,24 @@
 import {BrowserRouter, Route, Routes} from 'react-router-dom'
+import AppLayout from './components/AppLayout'
 import StartPage from './pages/StartPage'
 import SessionPage from './pages/SessionPage'
+import ScenariosPage from './pages/ScenariosPage'
+import CharactersPage from './pages/CharactersPage'
 
 /**
- * Root application component. Sets up client-side routing between the model
- * selection page and the active session page.
+ * Root application component. Sets up client-side routing with app shell:
+ * Home (start flow), Scenarios, Characters, and Session.
  */
 export default function App() {
     return (
         <BrowserRouter>
             <Routes>
-                <Route path="/" element={<StartPage/>}/>
-                <Route path="/session/:sessionId" element={<SessionPage/>}/>
+                <Route element={<AppLayout/>}>
+                    <Route path="/" element={<StartPage/>}/>
+                    <Route path="/scenarios" element={<ScenariosPage/>}/>
+                    <Route path="/characters" element={<CharactersPage/>}/>
+                    <Route path="/session/:sessionId" element={<SessionPage/>}/>
+                </Route>
             </Routes>
         </BrowserRouter>
     )

src/main/web/src/components/AppLayout.tsx

@@ -0,0 +1,54 @@
+import {AppBar, Box, Toolbar, Typography} from '@mui/material'
+import {Link as RouterLink, Outlet, useLocation} from 'react-router-dom'
+import {Link} from '@mui/material'
+
+/**
+ * Persistent app shell with top navigation. Renders the current route's page via Outlet.
+ */
+export default function AppLayout() {
+    const location = useLocation()
+    const navItems = [
+        { to: '/', label: 'Home' },
+        { to: '/scenarios', label: 'Scenarios' },
+        { to: '/characters', label: 'Characters' },
+    ]
+
+    return (
+        <Box sx={{ display: 'flex', flexDirection: 'column', minHeight: '100vh' }}>
+            <AppBar position="static" elevation={0}>
+                <Toolbar variant="dense">
+                    <Typography
+                        component={RouterLink}
+                        to="/"
+                        variant="h6"
+                        sx={{
+                            flexGrow: 1,
+                            textDecoration: 'none',
+                            color: 'inherit',
+                            fontWeight: 700,
+                        }}
+                    >
+                        RolePlay
+                    </Typography>
+                    <Box sx={{ display: 'flex', gap: 1 }}>
+                        {navItems.map(({ to, label }) => (
+                            <Link
+                                key={to}
+                                component={RouterLink}
+                                to={to}
+                                underline={location.pathname === to ? 'always' : 'hover'}
+                                color="inherit"
+                                sx={{ px: 1.5, py: 0.5, borderRadius: 1 }}
+                            >
+                                {label}
+                            </Link>
+                        ))}
+                    </Box>
+                </Toolbar>
+            </AppBar>
+            <Box component="main" sx={{ flexGrow: 1, p: 2 }}>
+                <Outlet />
+            </Box>
+        </Box>
+    )
+}

src/main/web/src/pages/CharactersPage.tsx

@@ -0,0 +1,308 @@
+import {useCallback, useEffect, useState} from 'react'
+import {
+    Alert,
+    Box,
+    Button,
+    Card,
+    CardContent,
+    CardActions,
+    CircularProgress,
+    Dialog,
+    DialogActions,
+    DialogContent,
+    DialogTitle,
+    IconButton,
+    TextField,
+    Typography,
+} from '@mui/material'
+import AddIcon from '@mui/icons-material/Add'
+import DeleteIcon from '@mui/icons-material/Delete'
+import EditIcon from '@mui/icons-material/Edit'
+import type {CharacterDefinition, CreateCharacterRequest} from '../api/generated/index'
+import {CharactersApi, Configuration} from '../api/generated/index'
+
+const API_BASE = '/api/v1'
+const charactersApi = new CharactersApi(new Configuration({basePath: API_BASE}))
+
+/** Parse comma- or newline-separated string into trimmed non-empty strings. */
+function parseList(value: string | undefined): string[] {
+    if (!value || !value.trim()) return []
+    return value
+        .split(/[,\n]/)
+        .map((s) => s.trim())
+        .filter(Boolean)
+}
+
+/** Format string array for display in a text field. */
+function formatList(arr: string[] | undefined): string {
+    return arr?.length ? arr.join(', ') : ''
+}
+
+/**
+ * Characters management page. Lists characters as cards with New/Edit/Delete.
+ */
+export default function CharactersPage() {
+    const [characters, setCharacters] = useState<CharacterDefinition[]>([])
+    const [loading, setLoading] = useState(true)
+    const [error, setError] = useState<string | null>(null)
+    const [dialogOpen, setDialogOpen] = useState(false)
+    const [editingId, setEditingId] = useState<string | null>(null)
+    const [saving, setSaving] = useState(false)
+    const [deleteConfirmId, setDeleteConfirmId] = useState<string | null>(null)
+
+    const [formName, setFormName] = useState('')
+    const [formRole, setFormRole] = useState('')
+    const [formBackstory, setFormBackstory] = useState('')
+    const [formSpeakingStyle, setFormSpeakingStyle] = useState('')
+    const [formPersonalityTraits, setFormPersonalityTraits] = useState('')
+    const [formGoals, setFormGoals] = useState('')
+
+    const loadCharacters = useCallback(async () => {
+        setLoading(true)
+        setError(null)
+        try {
+            const res = await charactersApi.listCharacters()
+            setCharacters(res.characters ?? [])
+        } catch (e: unknown) {
+            setError(e instanceof Error ? e.message : 'Failed to load characters')
+        } finally {
+            setLoading(false)
+        }
+    }, [])
+
+    useEffect(() => {
+        loadCharacters()
+    }, [loadCharacters])
+
+    const openCreate = () => {
+        setEditingId(null)
+        setFormName('')
+        setFormRole('')
+        setFormBackstory('')
+        setFormSpeakingStyle('')
+        setFormPersonalityTraits('')
+        setFormGoals('')
+        setDialogOpen(true)
+    }
+
+    const openEdit = (c: CharacterDefinition) => {
+        setEditingId(c.id)
+        setFormName(c.name)
+        setFormRole(c.role)
+        setFormBackstory(c.backstory ?? '')
+        setFormSpeakingStyle(c.speakingStyle ?? '')
+        setFormPersonalityTraits(formatList(c.personalityTraits))
+        setFormGoals(formatList(c.goals))
+        setDialogOpen(true)
+    }
+
+    const closeDialog = () => {
+        setDialogOpen(false)
+        setEditingId(null)
+    }
+
+    const handleSave = async () => {
+        if (!formName.trim() || !formRole.trim()) return
+        setSaving(true)
+        setError(null)
+        try {
+            const body: CreateCharacterRequest = {
+                name: formName.trim(),
+                role: formRole.trim(),
+                backstory: formBackstory.trim() || undefined,
+                speakingStyle: formSpeakingStyle.trim() || undefined,
+                personalityTraits: parseList(formPersonalityTraits).length
+                    ? parseList(formPersonalityTraits)
+                    : undefined,
+                goals: parseList(formGoals).length ? parseList(formGoals) : undefined,
+            }
+            if (editingId) {
+                body.id = editingId
+                await charactersApi.updateCharacter({characterId: editingId, createCharacterRequest: body})
+            } else {
+                await charactersApi.createCharacter({createCharacterRequest: body})
+            }
+            closeDialog()
+            await loadCharacters()
+        } catch (e: unknown) {
+            setError(e instanceof Error ? e.message : 'Failed to save character')
+        } finally {
+            setSaving(false)
+        }
+    }
+
+    const handleDelete = async (id: string) => {
+        setError(null)
+        try {
+            await charactersApi.deleteCharacter({characterId: id})
+            setDeleteConfirmId(null)
+            await loadCharacters()
+        } catch (e: unknown) {
+            setError(e instanceof Error ? e.message : 'Failed to delete character')
+        }
+    }
+
+    if (loading) {
+        return (
+            <Box sx={{display: 'flex', justifyContent: 'center', py: 4}}>
+                <CircularProgress/>
+            </Box>
+        )
+    }
+
+    return (
+        <>
+            <Box sx={{display: 'flex', alignItems: 'center', justifyContent: 'space-between', mb: 2}}>
+                <Typography variant="h4">Characters</Typography>
+                <Button variant="contained" startIcon={<AddIcon/>} onClick={openCreate}>
+                    New character
+                </Button>
+            </Box>
+
+            {error && (
+                <Alert severity="error" onClose={() => setError(null)} sx={{mb: 2}}>
+                    {error}
+                </Alert>
+            )}
+
+            {characters.length === 0 ? (
+                <Alert
+                    severity="info"
+                    action={
+                        <Button color="inherit" size="small" onClick={openCreate}>
+                            Create first character
+                        </Button>
+                    }
+                >
+                    No characters yet. Create your first character to use in scenarios.
+                </Alert>
+            ) : (
+                <Box sx={{display: 'flex', flexWrap: 'wrap', gap: 2}}>
+                    {characters.map((c) => (
+                        <Card key={c.id} sx={{minWidth: 280, maxWidth: 360}}>
+                            <CardContent>
+                                <Typography variant="h6">{c.name}</Typography>
+                                <Typography variant="body2" color="text.secondary">
+                                    {c.role}
+                                </Typography>
+                                {c.backstory && (
+                                    <Typography
+                                        variant="body2"
+                                        sx={{mt: 1}}
+                                        noWrap
+                                    >
+                                        {c.backstory}
+                                    </Typography>
+                                )}
+                            </CardContent>
+                            <CardActions disableSpacing>
+                                <IconButton
+                                    aria-label="Edit"
+                                    onClick={() => openEdit(c)}
+                                    size="small"
+                                >
+                                    <EditIcon/>
+                                </IconButton>
+                                <IconButton
+                                    aria-label="Delete"
+                                    onClick={() => setDeleteConfirmId(c.id)}
+                                    size="small"
+                                    color="error"
+                                >
+                                    <DeleteIcon/>
+                                </IconButton>
+                            </CardActions>
+                        </Card>
+                    ))}
+                </Box>
+            )}
+
+            <Dialog open={dialogOpen} onClose={closeDialog} maxWidth="sm" fullWidth>
+                <DialogTitle>{editingId ? 'Edit character' : 'New character'}</DialogTitle>
+                <DialogContent>
+                    <TextField
+                        autoFocus
+                        margin="dense"
+                        label="Name"
+                        required
+                        fullWidth
+                        value={formName}
+                        onChange={(e) => setFormName(e.target.value)}
+                    />
+                    <TextField
+                        margin="dense"
+                        label="Role"
+                        required
+                        fullWidth
+                        value={formRole}
+                        onChange={(e) => setFormRole(e.target.value)}
+                    />
+                    <TextField
+                        margin="dense"
+                        label="Backstory"
+                        fullWidth
+                        multiline
+                        minRows={2}
+                        value={formBackstory}
+                        onChange={(e) => setFormBackstory(e.target.value)}
+                    />
+                    <TextField
+                        margin="dense"
+                        label="Speaking style"
+                        fullWidth
+                        value={formSpeakingStyle}
+                        onChange={(e) => setFormSpeakingStyle(e.target.value)}
+                    />
+                    <TextField
+                        margin="dense"
+                        label="Personality traits (comma-separated)"
+                        fullWidth
+                        value={formPersonalityTraits}
+                        onChange={(e) => setFormPersonalityTraits(e.target.value)}
+                        placeholder="e.g. brave, stern, witty"
+                    />
+                    <TextField
+                        margin="dense"
+                        label="Goals (comma-separated)"
+                        fullWidth
+                        value={formGoals}
+                        onChange={(e) => setFormGoals(e.target.value)}
+                        placeholder="e.g. Find the treasure, Protect the crew"
+                    />
+                </DialogContent>
+                <DialogActions>
+                    <Button onClick={closeDialog}>Cancel</Button>
+                    <Button
+                        onClick={handleSave}
+                        variant="contained"
+                        disabled={saving || !formName.trim() || !formRole.trim()}
+                    >
+                        {saving ? 'Saving…' : editingId ? 'Update' : 'Create'}
+                    </Button>
+                </DialogActions>
+            </Dialog>
+
+            <Dialog
+                open={deleteConfirmId !== null}
+                onClose={() => setDeleteConfirmId(null)}
+            >
+                <DialogTitle>Delete character?</DialogTitle>
+                <DialogContent>
+                    <Typography>
+                        This cannot be undone. Scenarios using this character may need to be updated.
+                    </Typography>
+                </DialogContent>
+                <DialogActions>
+                    <Button onClick={() => setDeleteConfirmId(null)}>Cancel</Button>
+                    <Button
+                        color="error"
+                        variant="contained"
+                        onClick={() => deleteConfirmId && handleDelete(deleteConfirmId)}
+                    >
+                        Delete
+                    </Button>
+                </DialogActions>
+            </Dialog>
+        </>
+    )
+}

src/main/web/src/pages/ScenariosPage.tsx

@@ -0,0 +1,356 @@
+import {useCallback, useEffect, useState} from 'react'
+import {useNavigate} from 'react-router-dom'
+import {
+    Alert,
+    Box,
+    Button,
+    Card,
+    CardContent,
+    CardActions,
+    CircularProgress,
+    Dialog,
+    DialogActions,
+    DialogContent,
+    DialogTitle,
+    FormControl,
+    IconButton,
+    InputLabel,
+    MenuItem,
+    Select,
+    TextField,
+    Typography,
+} from '@mui/material'
+import AddIcon from '@mui/icons-material/Add'
+import DeleteIcon from '@mui/icons-material/Delete'
+import EditIcon from '@mui/icons-material/Edit'
+import PlayArrowIcon from '@mui/icons-material/PlayArrow'
+import type {
+    CharacterDefinition,
+    CreateScenarioRequest,
+    ScenarioSetup,
+    ScenarioSummary,
+} from '../api/generated/index'
+import {CharactersApi, Configuration, ScenariosApi} from '../api/generated/index'
+
+const API_BASE = '/api/v1'
+const scenariosApi = new ScenariosApi(new Configuration({basePath: API_BASE}))
+const charactersApi = new CharactersApi(new Configuration({basePath: API_BASE}))
+
+/**
+ * Scenarios management page. List cards with New/Edit/Delete/Start; form with character assignment.
+ */
+export default function ScenariosPage() {
+    const navigate = useNavigate()
+    const [scenarios, setScenarios] = useState<ScenarioSummary[]>([])
+    const [characters, setCharacters] = useState<CharacterDefinition[]>([])
+    const [loading, setLoading] = useState(true)
+    const [error, setError] = useState<string | null>(null)
+    const [dialogOpen, setDialogOpen] = useState(false)
+    const [editingId, setEditingId] = useState<string | null>(null)
+    const [saving, setSaving] = useState(false)
+    const [deleteConfirmId, setDeleteConfirmId] = useState<string | null>(null)
+
+    const [formName, setFormName] = useState('')
+    const [formSetting, setFormSetting] = useState('')
+    const [formInitialConflict, setFormInitialConflict] = useState('')
+    const [formUserCharacterId, setFormUserCharacterId] = useState<string>('')
+    const [formAiCharacterIds, setFormAiCharacterIds] = useState<string[]>([])
+
+    const loadScenarios = useCallback(async () => {
+        setLoading(true)
+        setError(null)
+        try {
+            const res = await scenariosApi.listScenarios()
+            setScenarios(res.scenarios ?? [])
+        } catch (e: unknown) {
+            setError(e instanceof Error ? e.message : 'Failed to load scenarios')
+        } finally {
+            setLoading(false)
+        }
+    }, [])
+
+    const loadCharacters = useCallback(async () => {
+        try {
+            const res = await charactersApi.listCharacters()
+            setCharacters(res.characters ?? [])
+        } catch {
+            setCharacters([])
+        }
+    }, [])
+
+    useEffect(() => {
+        loadScenarios()
+    }, [loadScenarios])
+
+    useEffect(() => {
+        loadCharacters()
+    }, [loadCharacters])
+
+    const openCreate = () => {
+        setEditingId(null)
+        setFormName('')
+        setFormSetting('')
+        setFormInitialConflict('')
+        setFormUserCharacterId('')
+        setFormAiCharacterIds([])
+        setDialogOpen(true)
+    }
+
+    const openEdit = async (s: ScenarioSummary) => {
+        setEditingId(s.id)
+        setFormName(s.name ?? '')
+        setFormSetting(s.setting ?? '')
+        setFormInitialConflict(s.initialConflict ?? '')
+        setFormUserCharacterId('')
+        setFormAiCharacterIds([])
+        setDialogOpen(true)
+        try {
+            const setup: ScenarioSetup = await scenariosApi.getScenario({scenarioId: s.id})
+            setFormSetting(setup.setting ?? formSetting)
+            setFormInitialConflict(setup.initialConflict ?? formInitialConflict)
+            if (setup.userCharacter?.id) setFormUserCharacterId(setup.userCharacter.id)
+            if (setup.aiCharacters?.length)
+                setFormAiCharacterIds(setup.aiCharacters.map((c) => c.id))
+        } catch (e: unknown) {
+            setError(e instanceof Error ? e.message : 'Failed to load scenario')
+        }
+    }
+
+    const closeDialog = () => {
+        setDialogOpen(false)
+        setEditingId(null)
+    }
+
+    const buildCharacterSlots = (): Array<{characterId: string; isUserCharacter: boolean; position: number}> => {
+        const slots: Array<{characterId: string; isUserCharacter: boolean; position: number}> = []
+        if (formUserCharacterId) {
+            slots.push({characterId: formUserCharacterId, isUserCharacter: true, position: 0})
+        }
+        formAiCharacterIds.forEach((id, i) => {
+            slots.push({characterId: id, isUserCharacter: false, position: i + 1})
+        })
+        return slots
+    }
+
+    const handleSave = async () => {
+        if (!formName.trim()) return
+        setSaving(true)
+        setError(null)
+        try {
+            const body: CreateScenarioRequest = {
+                name: formName.trim(),
+                setting: formSetting.trim() || undefined,
+                initialConflict: formInitialConflict.trim() || undefined,
+                characterSlots: buildCharacterSlots(), // always send array so backend receives list
+            }
+            if (editingId) {
+                await scenariosApi.updateScenario({scenarioId: editingId, createScenarioRequest: body})
+            } else {
+                await scenariosApi.createScenario({createScenarioRequest: body})
+            }
+            closeDialog()
+            await loadScenarios()
+        } catch (e: unknown) {
+            setError(e instanceof Error ? e.message : 'Failed to save scenario')
+        } finally {
+            setSaving(false)
+        }
+    }
+
+    const handleDelete = async (id: string) => {
+        setError(null)
+        try {
+            await scenariosApi.deleteScenario({scenarioId: id})
+            setDeleteConfirmId(null)
+            await loadScenarios()
+        } catch (e: unknown) {
+            setError(e instanceof Error ? e.message : 'Failed to delete scenario')
+        }
+    }
+
+    const handleStart = (scenarioId: string) => {
+        navigate('/', {state: {scenarioId}})
+    }
+
+    if (loading) {
+        return (
+            <Box sx={{display: 'flex', justifyContent: 'center', py: 4}}>
+                <CircularProgress/>
+            </Box>
+        )
+    }
+
+    return (
+        <>
+            <Box sx={{display: 'flex', alignItems: 'center', justifyContent: 'space-between', mb: 2}}>
+                <Typography variant="h4">Scenarios</Typography>
+                <Button variant="contained" startIcon={<AddIcon/>} onClick={openCreate}>
+                    New scenario
+                </Button>
+            </Box>
+
+            {error && (
+                <Alert severity="error" onClose={() => setError(null)} sx={{mb: 2}}>
+                    {error}
+                </Alert>
+            )}
+
+            {scenarios.length === 0 ? (
+                <Alert
+                    severity="info"
+                    action={
+                        <Button color="inherit" size="small" onClick={openCreate}>
+                            Create first scenario
+                        </Button>
+                    }
+                >
+                    No scenarios yet. Create your first scenario to start a story.
+                </Alert>
+            ) : (
+                <Box sx={{display: 'flex', flexWrap: 'wrap', gap: 2}}>
+                    {scenarios.map((s) => (
+                        <Card key={s.id} sx={{minWidth: 280, maxWidth: 360}}>
+                            <CardContent>
+                                <Typography variant="h6">{s.name}</Typography>
+                                {s.setting && (
+                                    <Typography variant="body2" color="text.secondary" noWrap>
+                                        {s.setting}
+                                    </Typography>
+                                )}
+                                {s.initialConflict && (
+                                    <Typography variant="body2" sx={{mt: 0.5}} noWrap>
+                                        {s.initialConflict}
+                                    </Typography>
+                                )}
+                            </CardContent>
+                            <CardActions disableSpacing>
+                                <Button
+                                    size="small"
+                                    startIcon={<PlayArrowIcon/>}
+                                    onClick={() => handleStart(s.id)}
+                                >
+                                    Start
+                                </Button>
+                                <IconButton aria-label="Edit" onClick={() => openEdit(s)} size="small">
+                                    <EditIcon/>
+                                </IconButton>
+                                <IconButton
+                                    aria-label="Delete"
+                                    onClick={() => setDeleteConfirmId(s.id)}
+                                    size="small"
+                                    color="error"
+                                >
+                                    <DeleteIcon/>
+                                </IconButton>
+                            </CardActions>
+                        </Card>
+                    ))}
+                </Box>
+            )}
+
+            <Dialog open={dialogOpen} onClose={closeDialog} maxWidth="sm" fullWidth>
+                <DialogTitle>{editingId ? 'Edit scenario' : 'New scenario'}</DialogTitle>
+                <DialogContent>
+                    <TextField
+                        autoFocus
+                        margin="dense"
+                        label="Name"
+                        required
+                        fullWidth
+                        value={formName}
+                        onChange={(e) => setFormName(e.target.value)}
+                    />
+                    <TextField
+                        margin="dense"
+                        label="Setting"
+                        fullWidth
+                        multiline
+                        minRows={2}
+                        value={formSetting}
+                        onChange={(e) => setFormSetting(e.target.value)}
+                        placeholder="Place, time, and atmosphere"
+                    />
+                    <TextField
+                        margin="dense"
+                        label="Initial conflict"
+                        fullWidth
+                        multiline
+                        minRows={2}
+                        value={formInitialConflict}
+                        onChange={(e) => setFormInitialConflict(e.target.value)}
+                    />
+                    <FormControl fullWidth margin="dense" size="small">
+                        <InputLabel>User character</InputLabel>
+                        <Select
+                            value={formUserCharacterId}
+                            label="User character"
+                            onChange={(e) => setFormUserCharacterId(e.target.value)}
+                        >
+                            <MenuItem value="">— None —</MenuItem>
+                            {characters.map((c) => (
+                                <MenuItem key={c.id} value={c.id}>
+                                    {c.name} ({c.role})
+                                </MenuItem>
+                            ))}
+                        </Select>
+                    </FormControl>
+                    <FormControl fullWidth margin="dense" size="small">
+                        <InputLabel>AI characters</InputLabel>
+                        <Select
+                            multiple
+                            value={formAiCharacterIds}
+                            label="AI characters"
+                            onChange={(e) =>
+                                setFormAiCharacterIds(
+                                    typeof e.target.value === 'string'
+                                        ? []
+                                        : (e.target.value as string[])
+                                )
+                            }
+                            renderValue={(selected) =>
+                                selected
+                                    .map((id) => characters.find((c) => c.id === id)?.name ?? id)
+                                    .join(', ')
+                            }
+                        >
+                            {characters
+                                .filter((c) => c.id !== formUserCharacterId)
+                                .map((c) => (
+                                    <MenuItem key={c.id} value={c.id}>
+                                        {c.name} ({c.role})
+                                    </MenuItem>
+                                ))}
+                        </Select>
+                    </FormControl>
+                </DialogContent>
+                <DialogActions>
+                    <Button onClick={closeDialog}>Cancel</Button>
+                    <Button
+                        onClick={handleSave}
+                        variant="contained"
+                        disabled={saving || !formName.trim()}
+                    >
+                        {saving ? 'Saving…' : editingId ? 'Update' : 'Create'}
+                    </Button>
+                </DialogActions>
+            </Dialog>
+
+            <Dialog open={deleteConfirmId !== null} onClose={() => setDeleteConfirmId(null)}>
+                <DialogTitle>Delete scenario?</DialogTitle>
+                <DialogContent>
+                    <Typography>This cannot be undone.</Typography>
+                </DialogContent>
+                <DialogActions>
+                    <Button onClick={() => setDeleteConfirmId(null)}>Cancel</Button>
+                    <Button
+                        color="error"
+                        variant="contained"
+                        onClick={() => deleteConfirmId && handleDelete(deleteConfirmId)}
+                    >
+                        Delete
+                    </Button>
+                </DialogActions>
+            </Dialog>
+        </>
+    )
+}

src/main/web/src/pages/StartPage.tsx

@@ -1,5 +1,5 @@
-import {useEffect, useState} from 'react'
-import {useNavigate} from 'react-router-dom'
+import {useEffect, useRef, useState} from 'react'
+import {useLocation, useNavigate} from 'react-router-dom'
 import {
     Accordion,
     AccordionDetails,
@@ -59,6 +59,8 @@ const scenariosApi = new ScenariosApi(new Configuration({basePath: API_BASE}))
  */
 export default function StartPage() {
     const navigate = useNavigate()
+    const location = useLocation()
+    const deepLinkApplied = useRef(false)
 
     const [models, setModels] = useState<ModelInfo[]>([])
     const [selectedModel, setSelectedModel] = useState<string>('')
@@ -100,6 +102,25 @@ export default function StartPage() {
             .finally(() => setLoading(false))
     }, [])
 
+    /** When arriving from Scenarios "Start" with state.scenarioId, pre-select that scenario and load its setup. */
+    useEffect(() => {
+        const state = location.state as { scenarioId?: string } | null
+        const id = state?.scenarioId
+        if (!id || deepLinkApplied.current || scenarios.length === 0) return
+        if (!scenarios.some((s) => s.id === id)) return
+        deepLinkApplied.current = true
+        setSelectedScenarioId(id)
+        scenariosApi
+            .getScenario({scenarioId: id})
+            .then((setup) => {
+                setSetting(setup.setting ?? '')
+                setInitialConflict(setup.initialConflict ?? '')
+                setUserCharacter(setup.userCharacter ?? null)
+                setAiCharacters(setup.aiCharacters ?? [])
+            })
+            .catch(() => setError('Could not load scenario.'))
+    }, [scenarios, location.state])
+
     const handleModelChange = (event: SelectChangeEvent) => {
         setSelectedModel(event.target.value)
     }

src/test/java/de/neitzel/roleplay/business/CharacterServiceTest.java

@@ -0,0 +1,131 @@
+package de.neitzel.roleplay.business;
+
+import de.neitzel.roleplay.data.CharacterEntity;
+import de.neitzel.roleplay.data.CharacterRepository;
+import de.neitzel.roleplay.fascade.model.CharacterDefinition;
+import de.neitzel.roleplay.fascade.model.CreateCharacterRequest;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.util.List;
+import java.util.UUID;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+/**
+ * Unit tests for {@link CharacterService}.
+ */
+@ExtendWith(MockitoExtension.class)
+class CharacterServiceTest {
+
+    @Mock
+    private CharacterRepository characterRepository;
+
+    private CharacterService characterService;
+
+    @BeforeEach
+    void setUp() {
+        characterService = new CharacterService(characterRepository);
+    }
+
+    @Test
+    void createPersistsWithGeneratedIdAndReturnsDefinition() {
+        CreateCharacterRequest request = new CreateCharacterRequest("Captain Morgan", "captain");
+        request.setBackstory("Sea veteran");
+        request.setSpeakingStyle("Gruff");
+        request.setPersonalityTraits(List.of("brave", "stern"));
+        request.setGoals(List.of("Find the treasure"));
+
+        CharacterDefinition result = characterService.create(request);
+
+        assertNotNull(result.getId());
+        assertEquals("Captain Morgan", result.getName());
+        assertEquals("captain", result.getRole());
+        assertEquals("Sea veteran", result.getBackstory());
+        assertEquals("Gruff", result.getSpeakingStyle());
+        assertEquals(List.of("brave", "stern"), result.getPersonalityTraits());
+        assertEquals(List.of("Find the treasure"), result.getGoals());
+        ArgumentCaptor<CharacterEntity> captor = ArgumentCaptor.forClass(CharacterEntity.class);
+        verify(characterRepository).persist(captor.capture());
+        assertEquals("Captain Morgan", captor.getValue().getName());
+        assertEquals("captain", captor.getValue().getRole());
+    }
+
+    @Test
+    void createUsesRequestIdWhenProvided() {
+        UUID id = UUID.fromString("11111111-1111-1111-1111-111111111101");
+        CreateCharacterRequest request = new CreateCharacterRequest("Name", "role");
+        request.setId(id);
+
+        CharacterDefinition result = characterService.create(request);
+
+        assertEquals(id.toString(), result.getId());
+        ArgumentCaptor<CharacterEntity> captor = ArgumentCaptor.forClass(CharacterEntity.class);
+        verify(characterRepository).persist(captor.capture());
+        assertEquals(id, captor.getValue().getId());
+    }
+
+    @Test
+    void updateReplacesAndPersists() {
+        UUID id = UUID.fromString("11111111-1111-1111-1111-111111111101");
+        CharacterEntity existing = new CharacterEntity();
+        existing.setId(id);
+        existing.setName("Old");
+        existing.setRole("oldRole");
+        when(characterRepository.findByIdOptional(id)).thenReturn(existing);
+
+        CreateCharacterRequest request = new CreateCharacterRequest("New Name", "newRole");
+        request.setBackstory("Updated backstory");
+
+        CharacterDefinition result = characterService.update(id, request);
+
+        assertEquals(id.toString(), result.getId());
+        assertEquals("New Name", result.getName());
+        assertEquals("newRole", result.getRole());
+        assertEquals("Updated backstory", result.getBackstory());
+        verify(characterRepository).persist(existing);
+        assertEquals("New Name", existing.getName());
+    }
+
+    @Test
+    void updateThrowsWhenCharacterNotFound() {
+        UUID id = UUID.randomUUID();
+        when(characterRepository.findByIdOptional(id)).thenReturn(null);
+        CreateCharacterRequest request = new CreateCharacterRequest("Name", "role");
+
+        assertThrows(java.util.NoSuchElementException.class,
+                () -> characterService.update(id, request));
+    }
+
+    @Test
+    void deleteReturnsTrueAndDeletesWhenFound() {
+        UUID id = UUID.randomUUID();
+        CharacterEntity entity = new CharacterEntity();
+        entity.setId(id);
+        when(characterRepository.findByIdOptional(id)).thenReturn(entity);
+
+        boolean result = characterService.delete(id);
+
+        assertTrue(result);
+        verify(characterRepository).delete(entity);
+    }
+
+    @Test
+    void deleteReturnsFalseWhenNotFound() {
+        UUID id = UUID.randomUUID();
+        when(characterRepository.findByIdOptional(id)).thenReturn(null);
+
+        boolean result = characterService.delete(id);
+
+        assertTrue(!result);
+    }
+}

src/test/java/de/neitzel/roleplay/business/ScenarioServiceTest.java

@@ -1,14 +1,20 @@
 package de.neitzel.roleplay.business;
 
+import jakarta.persistence.EntityManager;
+
 import de.neitzel.roleplay.data.CharacterEntity;
+import de.neitzel.roleplay.data.CharacterRepository;
 import de.neitzel.roleplay.data.ScenarioCharacterEntity;
 import de.neitzel.roleplay.data.ScenarioEntity;
 import de.neitzel.roleplay.data.ScenarioRepository;
+import de.neitzel.roleplay.fascade.model.CreateScenarioRequest;
+import de.neitzel.roleplay.fascade.model.ScenarioCharacterSlot;
 import de.neitzel.roleplay.fascade.model.ScenarioSetup;
 import de.neitzel.roleplay.fascade.model.ScenarioSummary;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.ArgumentCaptor;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
 
@@ -18,7 +24,9 @@ import java.util.UUID;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 /**
@@ -30,11 +38,17 @@ class ScenarioServiceTest {
     @Mock
     private ScenarioRepository scenarioRepository;
 
+    @Mock
+    private CharacterRepository characterRepository;
+
+    @Mock
+    private EntityManager entityManager;
+
     private ScenarioService scenarioService;
 
     @BeforeEach
     void setUp() {
-        scenarioService = new ScenarioService(scenarioRepository);
+        scenarioService = new ScenarioService(scenarioRepository, characterRepository, entityManager);
     }
 
     @Test
@@ -124,4 +138,105 @@ class ScenarioServiceTest {
         assertEquals("Captain Morgan", setup.getAiCharacters().get(0).getName());
         assertEquals("captain", setup.getAiCharacters().get(0).getRole());
     }
+
+    @Test
+    void createScenarioPersistsAndReturnsSummary() {
+        UUID charId = UUID.fromString("11111111-1111-1111-1111-111111111101");
+        CharacterEntity character = new CharacterEntity();
+        character.setId(charId);
+        character.setName("Detective");
+        character.setRole("detective");
+        when(characterRepository.findByIdOptional(charId)).thenReturn(character);
+
+        ScenarioCharacterSlot slot = new ScenarioCharacterSlot(charId, true, 0);
+        CreateScenarioRequest request = new CreateScenarioRequest("Mystery");
+        request.setSetting("A harbour");
+        request.setInitialConflict("Noises");
+        request.setCharacterSlots(List.of(slot));
+
+        ScenarioSummary result = scenarioService.create(request);
+
+        assertNotNull(result.getId());
+        assertEquals("Mystery", result.getName());
+        assertEquals("A harbour", result.getSetting());
+        assertEquals("Noises", result.getInitialConflict());
+        ArgumentCaptor<ScenarioEntity> captor = ArgumentCaptor.forClass(ScenarioEntity.class);
+        verify(scenarioRepository).persist(captor.capture());
+        assertEquals(1, captor.getValue().getScenarioCharacters().size());
+        assertTrue(captor.getValue().getScenarioCharacters().get(0).isUserCharacter());
+    }
+
+    @Test
+    void createScenarioThrowsWhenCharacterNotFound() {
+        UUID charId = UUID.randomUUID();
+        when(characterRepository.findByIdOptional(charId)).thenReturn(null);
+        ScenarioCharacterSlot slot = new ScenarioCharacterSlot(charId, false, 1);
+        CreateScenarioRequest request = new CreateScenarioRequest("Mystery");
+        request.setCharacterSlots(List.of(slot));
+
+        assertThrows(IllegalArgumentException.class, () -> scenarioService.create(request));
+    }
+
+    @Test
+    void updateScenarioReplacesAndPersists() {
+        UUID scenarioId = UUID.fromString("22222222-2222-2222-2222-222222222201");
+        UUID charId = UUID.fromString("11111111-1111-1111-1111-111111111101");
+        CharacterEntity character = new CharacterEntity();
+        character.setId(charId);
+        character.setName("Detective");
+        character.setRole("detective");
+        ScenarioEntity existing = new ScenarioEntity();
+        existing.setId(scenarioId);
+        existing.setName("Old");
+        existing.setScenarioCharacters(new java.util.ArrayList<>());
+
+        when(scenarioRepository.findByIdWithCharacters(scenarioId)).thenReturn(existing);
+        when(characterRepository.findByIdOptional(charId)).thenReturn(character);
+
+        ScenarioCharacterSlot slot = new ScenarioCharacterSlot(charId, true, 0);
+        CreateScenarioRequest request = new CreateScenarioRequest("Updated");
+        request.setSetting("New setting");
+        request.setCharacterSlots(List.of(slot));
+
+        ScenarioSummary result = scenarioService.update(scenarioId, request);
+
+        assertEquals(scenarioId, result.getId());
+        assertEquals("Updated", result.getName());
+        assertEquals("New setting", result.getSetting());
+        verify(scenarioRepository).persist(existing);
+        assertEquals(1, existing.getScenarioCharacters().size());
+    }
+
+    @Test
+    void updateScenarioThrowsWhenScenarioNotFound() {
+        UUID scenarioId = UUID.randomUUID();
+        when(scenarioRepository.findByIdWithCharacters(scenarioId)).thenReturn(null);
+        CreateScenarioRequest request = new CreateScenarioRequest("Name");
+
+        assertThrows(java.util.NoSuchElementException.class,
+                () -> scenarioService.update(scenarioId, request));
+    }
+
+    @Test
+    void deleteScenarioReturnsTrueWhenFound() {
+        UUID scenarioId = UUID.randomUUID();
+        ScenarioEntity scenario = new ScenarioEntity();
+        scenario.setId(scenarioId);
+        when(scenarioRepository.findByIdWithCharacters(scenarioId)).thenReturn(scenario);
+
+        boolean result = scenarioService.delete(scenarioId);
+
+        assertTrue(result);
+        verify(scenarioRepository).delete(scenario);
+    }
+
+    @Test
+    void deleteScenarioReturnsFalseWhenNotFound() {
+        UUID scenarioId = UUID.randomUUID();
+        when(scenarioRepository.findByIdWithCharacters(scenarioId)).thenReturn(null);
+
+        boolean result = scenarioService.delete(scenarioId);
+
+        assertTrue(!result);
+    }
 }