diff --git a/src/component-models/structure.normalizer.ts b/src/component-models/structure.normalizer.ts
new file mode 100644
index 0000000..75bff4f
--- /dev/null
+++ b/src/component-models/structure.normalizer.ts
@@ -0,0 +1,109 @@
+import type { ComponentModelStructure } from '../shared/types/inventory';
+
+type InputValue = Record<string, unknown> | null | undefined;
+
+const toArray = (value: unknown): unknown[] => {
+  if (Array.isArray(value)) {
+    return value;
+  }
+  if (value === undefined || value === null) {
+    return [];
+  }
+  return [value];
+};
+
+const sanitizeRole = (role: unknown): string | undefined => {
+  if (role === undefined || role === null) {
+    return undefined;
+  }
+  const stringValue = String(role).trim();
+  return stringValue ? stringValue : undefined;
+};
+
+const sanitizeAlias = (alias: unknown): string | undefined => {
+  if (alias === undefined || alias === null) {
+    return undefined;
+  }
+  const stringValue = String(alias).trim();
+  return stringValue ? stringValue : undefined;
+};
+
+const ensureString = (value: unknown): string => String(value ?? '');
+
+export function normalizeComponentModelStructure(
+  input: unknown,
+): ComponentModelStructure {
+  const structure = (input ?? {}) as InputValue;
+
+  const pieces = toArray((structure as any)?.pieces).map((piece) => {
+    const candidate = piece as Record<string, unknown> | null | undefined;
+    if (candidate?.familyCode) {
+      return {
+        familyCode: ensureString(candidate.familyCode).trim() || 'UNKNOWN',
+        role: sanitizeRole(candidate.role),
+      } as ComponentModelStructure['pieces'][number];
+    }
+    if (candidate?.typePieceId) {
+      return {
+        typePieceId: ensureString(candidate.typePieceId).trim() || 'UNKNOWN',
+        role: sanitizeRole(candidate.role),
+      } as ComponentModelStructure['pieces'][number];
+    }
+
+    return {
+      familyCode:
+        ensureString(
+          candidate?.familyCode ?? candidate?.name ?? candidate?.typePieceLabel ?? 'UNKNOWN',
+        ).trim() || 'UNKNOWN',
+      role: sanitizeRole(candidate?.role),
+    } as ComponentModelStructure['pieces'][number];
+  });
+
+  const customFields = toArray((structure as any)?.customFields).map((field) => {
+    const candidate = field as Record<string, unknown> | null | undefined;
+    const key = ensureString(candidate?.key ?? candidate?.name ?? 'unknown').trim();
+
+    return {
+      key: key || 'unknown',
+      value: candidate?.value ?? null,
+    };
+  });
+
+  const rawSubcomponents = toArray(
+    (structure as any)?.subcomponents ?? (structure as any)?.subComponents,
+  );
+
+  const subcomponents = rawSubcomponents.map((subcomponent) => {
+    const candidate = subcomponent as Record<string, unknown> | null | undefined;
+
+    if (candidate?.modelId) {
+      return {
+        modelId: ensureString(candidate.modelId).trim() || 'UNKNOWN',
+        alias: sanitizeAlias(candidate?.alias ?? candidate?.name),
+      } as ComponentModelStructure['subcomponents'][number];
+    }
+    if (candidate?.familyCode) {
+      return {
+        familyCode: ensureString(candidate.familyCode).trim() || 'UNKNOWN',
+        alias: sanitizeAlias(candidate?.alias ?? candidate?.name),
+      } as ComponentModelStructure['subcomponents'][number];
+    }
+    if (candidate?.typeComposantId) {
+      return {
+        typeComposantId: ensureString(candidate.typeComposantId).trim() || 'UNKNOWN',
+        alias: sanitizeAlias(candidate?.alias ?? candidate?.name),
+      } as ComponentModelStructure['subcomponents'][number];
+    }
+
+    return {
+      familyCode: ensureString(candidate?.name ?? 'UNKNOWN').trim() || 'UNKNOWN',
+      alias: sanitizeAlias(candidate?.alias ?? candidate?.name),
+    } as ComponentModelStructure['subcomponents'][number];
+  });
+
+  return {
+    pieces,
+    customFields,
+    subcomponents,
+  };
+}
diff --git a/src/composants/composants.service.ts b/src/composants/composants.service.ts
index 6887f73..0a4cf84 100644
--- a/src/composants/composants.service.ts
+++ b/src/composants/composants.service.ts
@@ -123,7 +123,8 @@ export class ComposantsService {
       include: COMPONENT_WITH_RELATIONS_INCLUDE,
     })) as ComposantWithRelations;
 
-    return this.getComponentWithHierarchy(created.id);
+    const component = await this.getComponentWithHierarchy(created.id);
+    return component ?? created;
   }
 
   async findAll() {
@@ -244,9 +245,13 @@ export class ComposantsService {
       }
     }
 
-    const subComponents = Array.isArray(structure?.subComponents)
-      ? structure.subComponents
-      : [];
+    const rawSubcomponents =
+      (structure as any)?.subcomponents ?? structure?.subComponents;
+    const subComponents = Array.isArray(rawSubcomponents)
+      ? rawSubcomponents
+      : rawSubcomponents
+        ? [rawSubcomponents]
+        : [];
     for (const sub of subComponents) {
       const subTypeId = this.extractTypeComposantId(sub);
       if (!subTypeId) {
diff --git a/src/custom-fields/custom-fields.service.spec.ts b/src/custom-fields/custom-fields.service.spec.ts
index da568f1..50b6f5b 100644
--- a/src/custom-fields/custom-fields.service.spec.ts
+++ b/src/custom-fields/custom-fields.service.spec.ts
@@ -152,9 +152,3 @@ describe('CustomFieldsService', () => {
     });
   });
 });
-      expect(prisma.customField.findFirst).toHaveBeenCalledWith({
-        where: {
-          name: 'Température maximale',
-          typeMachineId: 'type-1',
-        },
-      });
diff --git a/src/machines/machines.service.ts b/src/machines/machines.service.ts
index e9227f3..65d2e1b 100644
--- a/src/machines/machines.service.ts
+++ b/src/machines/machines.service.ts
@@ -537,11 +537,19 @@ export class MachinesService {
       : prepared.pieces
         ? [prepared.pieces]
         : [];
-    prepared.subComponents = Array.isArray(prepared.subComponents)
-      ? prepared.subComponents
-      : prepared.subComponents
-        ? [prepared.subComponents]
+    const rawSubcomponents =
+      (definition as any)?.subcomponents ??
+      (definition as any)?.subComponents ??
+      prepared.subcomponents ??
+      prepared.subComponents ??
+      [];
+    const subcomponents = Array.isArray(rawSubcomponents)
+      ? rawSubcomponents
+      : rawSubcomponents
+        ? [rawSubcomponents]
         : [];
+    prepared.subcomponents = subcomponents;
+    prepared.subComponents = subcomponents;
 
     prepared.typeComposantId =
       prepared.typeComposantId ||
@@ -608,9 +616,13 @@ export class MachinesService {
       const componentPieces = Array.isArray(component.pieces)
         ? component.pieces
         : [];
-      const subComponents = Array.isArray(component.subComponents)
-        ? component.subComponents
-        : [];
+      const rawSubcomponents =
+        component.subcomponents ?? component.subComponents ?? [];
+      const subComponents = Array.isArray(rawSubcomponents)
+        ? rawSubcomponents
+        : rawSubcomponents
+          ? [rawSubcomponents]
+          : [];
 
       const componentModelId = component.__componentModelId ?? null;
       const requirementId = component.__requirementId ?? null;
diff --git a/src/shared/dto/type.dto.ts b/src/shared/dto/type.dto.ts
index 994e82d..8837535 100644
--- a/src/shared/dto/type.dto.ts
+++ b/src/shared/dto/type.dto.ts
@@ -9,6 +9,7 @@ import {
 } from 'class-validator';
 import { Type } from 'class-transformer';
 import { ValidateNested } from 'class-validator';
+import type { ComponentModelStructure } from '../types/inventory';
 
 export enum CustomFieldType {
   TEXT = 'text',
@@ -251,7 +252,7 @@ export class CreateComposantModelDto {
   typeComposantId: string;
 
   @IsOptional()
-  structure?: any;
+  structure?: ComponentModelStructure;
 }
 
 export class UpdateComposantModelDto {
@@ -268,7 +269,7 @@ export class UpdateComposantModelDto {
   typeComposantId?: string;
 
   @IsOptional()
-  structure?: any;
+  structure?: ComponentModelStructure;
 }
 
 export class CreatePieceModelDto {
diff --git a/src/shared/schemas/inventory.ts b/src/shared/schemas/inventory.ts
new file mode 100644
index 0000000..6750f25
--- /dev/null
+++ b/src/shared/schemas/inventory.ts
@@ -0,0 +1,152 @@
+import { normalizeComponentModelStructure } from '../../component-models/structure.normalizer';
+import type { ComponentModelStructure } from '../types/inventory';
+
+export class ComponentModelStructureValidationError extends Error {
+  constructor(message: string) {
+    super(message);
+    this.name = 'ComponentModelStructureValidationError';
+  }
+}
+
+function assertString(value: unknown, context: string): string {
+  if (typeof value !== 'string') {
+    throw new ComponentModelStructureValidationError(
+      `${context} doit être une chaîne de caractères`,
+    );
+  }
+  return value;
+}
+
+function sanitizeOptionalString(value: unknown): string | undefined {
+  if (value === undefined || value === null) {
+    return undefined;
+  }
+  return String(value);
+}
+
+function validatePieces(
+  pieces: ComponentModelStructure['pieces'],
+): ComponentModelStructure['pieces'] {
+  return pieces.map((piece, index) => {
+    if ('familyCode' in piece) {
+      const familyCode = assertString(
+        piece.familyCode,
+        `pieces[${index}].familyCode`,
+      ).trim();
+      if (!familyCode) {
+        throw new ComponentModelStructureValidationError(
+          `pieces[${index}].familyCode ne peut pas être vide`,
+        );
+      }
+      return {
+        familyCode,
+        role: sanitizeOptionalString(piece.role),
+      };
+    }
+
+    if ('typePieceId' in piece) {
+      const typePieceId = assertString(
+        piece.typePieceId,
+        `pieces[${index}].typePieceId`,
+      ).trim();
+      if (!typePieceId) {
+        throw new ComponentModelStructureValidationError(
+          `pieces[${index}].typePieceId ne peut pas être vide`,
+        );
+      }
+      return {
+        typePieceId,
+        role: sanitizeOptionalString(piece.role),
+      };
+    }
+
+    throw new ComponentModelStructureValidationError(
+      `pieces[${index}] doit définir "familyCode" ou "typePieceId"`,
+    );
+  });
+}
+
+function validateCustomFields(
+  customFields: ComponentModelStructure['customFields'],
+): ComponentModelStructure['customFields'] {
+  return customFields.map((field, index) => {
+    const key = assertString(field.key, `customFields[${index}].key`).trim();
+    if (!key) {
+      throw new ComponentModelStructureValidationError(
+        `customFields[${index}].key ne peut pas être vide`,
+      );
+    }
+
+    return { key, value: field.value };
+  });
+}
+
+function validateSubcomponents(
+  subcomponents: ComponentModelStructure['subcomponents'],
+): ComponentModelStructure['subcomponents'] {
+  return subcomponents.map((subcomponent, index) => {
+    if ('modelId' in subcomponent) {
+      const modelId = assertString(
+        subcomponent.modelId,
+        `subcomponents[${index}].modelId`,
+      ).trim();
+      if (!modelId) {
+        throw new ComponentModelStructureValidationError(
+          `subcomponents[${index}].modelId ne peut pas être vide`,
+        );
+      }
+      return {
+        modelId,
+        alias: sanitizeOptionalString(subcomponent.alias),
+      };
+    }
+
+    if ('familyCode' in subcomponent) {
+      const familyCode = assertString(
+        subcomponent.familyCode,
+        `subcomponents[${index}].familyCode`,
+      ).trim();
+      if (!familyCode) {
+        throw new ComponentModelStructureValidationError(
+          `subcomponents[${index}].familyCode ne peut pas être vide`,
+        );
+      }
+      return {
+        familyCode,
+        alias: sanitizeOptionalString(subcomponent.alias),
+      };
+    }
+
+    if ('typeComposantId' in subcomponent) {
+      const typeComposantId = assertString(
+        subcomponent.typeComposantId,
+        `subcomponents[${index}].typeComposantId`,
+      ).trim();
+      if (!typeComposantId) {
+        throw new ComponentModelStructureValidationError(
+          `subcomponents[${index}].typeComposantId ne peut pas être vide`,
+        );
+      }
+      return {
+        typeComposantId,
+        alias: sanitizeOptionalString(subcomponent.alias),
+      };
+    }
+
+    throw new ComponentModelStructureValidationError(
+      `subcomponents[${index}] doit définir "modelId", "familyCode" ou "typeComposantId"`,
+    );
+  });
+}
+
+export const ComponentModelStructureSchema = {
+  parse(input: unknown): ComponentModelStructure {
+    const normalized = normalizeComponentModelStructure(input);
+
+    return {
+      pieces: validatePieces(normalized.pieces),
+      customFields: validateCustomFields(normalized.customFields),
+      subcomponents: validateSubcomponents(normalized.subcomponents),
+    };
+  },
+};
diff --git a/src/shared/types/inventory.ts b/src/shared/types/inventory.ts
new file mode 100644
index 0000000..ff5f000
--- /dev/null
+++ b/src/shared/types/inventory.ts
@@ -0,0 +1,41 @@
+/**
+ * Structure canonique d'un ComponentModel.
+ */
+export type ComponentModelStructure = {
+  /**
+   * Familles de pièces autorisées (ou identifiant de famille) — pas de quantité ici.
+   */
+  pieces: Array<
+    | {
+        familyCode: string;
+        role?: string;
+      }
+    | {
+        typePieceId: string;
+        role?: string;
+      }
+  >;
+
+  /**
+   * Valeurs par défaut au niveau "modèle" (libres, mais clé obligatoire).
+   */
+  customFields: Array<{ key: string; value: unknown }>;
+
+  /**
+   * Sous-composants : soit on pointe un modèle précis, soit on autorise une famille.
+   */
+  subcomponents: Array<
+    | {
+        modelId: string;
+        alias?: string;
+      }
+    | {
+        familyCode: string;
+        alias?: string;
+      }
+    | {
+        typeComposantId: string;
+        alias?: string;
+      }
+  >;
+};
diff --git a/src/types/services/composant-model.service.ts b/src/types/services/composant-model.service.ts
index 61c4bac..ca5142e 100644
--- a/src/types/services/composant-model.service.ts
+++ b/src/types/services/composant-model.service.ts
@@ -1,9 +1,12 @@
 import { Injectable } from '@nestjs/common';
 import { ComposantModelsRepository } from '../../common/repositories/composant-models.repository';
+import type { Prisma } from '@prisma/client';
 import {
   CreateComposantModelDto,
   UpdateComposantModelDto,
 } from '../../shared/dto/type.dto';
+import { ComponentModelStructureSchema } from '../../shared/schemas/inventory';
+import type { ComponentModelStructure } from '../../shared/types/inventory';
 
 const COMPOSANT_MODEL_INCLUDE = {
   typeComposant: true,
@@ -14,40 +17,81 @@ export class ComposantModelService {
   constructor(private readonly repository: ComposantModelsRepository) {}
 
   async create(dto: CreateComposantModelDto) {
-    const { typeComposantId, ...data } = dto;
-    return this.repository.create(
+    const { typeComposantId, structure, ...data } = dto;
+    const parsedStructure = this.parseStructure(structure);
+
+    const created = await this.repository.create(
       {
         ...data,
+        structure: parsedStructure as Prisma.InputJsonValue,
         typeComposant: { connect: { id: typeComposantId } },
       },
       COMPOSANT_MODEL_INCLUDE,
     );
+
+    return this.withParsedStructure(created);
   }
 
   async findAll(typeComposantId?: string) {
-    return this.repository.findAll(typeComposantId, COMPOSANT_MODEL_INCLUDE);
+    const models = await this.repository.findAll(
+      typeComposantId,
+      COMPOSANT_MODEL_INCLUDE,
+    );
+
+    return models.map((model) => this.mapStructure(model));
   }
 
   async findOne(id: string) {
-    return this.repository.findOne(id, COMPOSANT_MODEL_INCLUDE);
+    const model = await this.repository.findOne(id, COMPOSANT_MODEL_INCLUDE);
+    return this.withParsedStructure(model);
   }
 
   async update(id: string, dto: UpdateComposantModelDto) {
-    const { typeComposantId, ...data } = dto;
+    const { typeComposantId, structure, ...data } = dto;
 
-    return this.repository.update(
+    const parsedStructure =
+      structure !== undefined ? this.parseStructure(structure) : undefined;
+
+    const updated = await this.repository.update(
       id,
       {
         ...data,
+        ...(parsedStructure
+          ? { structure: parsedStructure as Prisma.InputJsonValue }
+          : {}),
         ...(typeComposantId
           ? { typeComposant: { connect: { id: typeComposantId } } }
           : {}),
       },
       COMPOSANT_MODEL_INCLUDE,
     );
+
+    return this.withParsedStructure(updated);
   }
 
   async remove(id: string) {
     return this.repository.delete(id);
   }
+
+  private parseStructure(
+    structure: unknown | undefined,
+  ): ComponentModelStructure {
+    return ComponentModelStructureSchema.parse(structure);
+  }
+
+  private mapStructure<T extends { structure?: unknown }>(
+    model: T,
+  ): T & { structure: ComponentModelStructure } {
+    const structure = this.parseStructure((model as any).structure);
+    return {
+      ...model,
+      structure,
+    };
+  }
+
+  private withParsedStructure<T extends { structure?: unknown }>(
+    model: T | null,
+  ): (T & { structure: ComponentModelStructure }) | null {
+    return model ? this.mapStructure(model) : null;
+  }
 }