SAP OData to MCP Server

Instructions

Implementation Reference

• src/utils/validation-schemas.ts:85-90 (schema)

  Zod input validation schema for the get-entity-schema tool defining serviceId, entityName, and optional flags

  export const EntitySchemaSchema = z.object({
    serviceId: serviceName,
    entityName: entitySetName,
    includeNavigations: z.boolean().optional(),
    includeConstraints: z.boolean().optional(),
  });

• src/middleware/mcp-auth.ts:560-567 (registration)

  get-entity-schema registered as public discovery tool that does not require authentication (requiresAuth returns false)

    'get-entity-schema',
  
    // System tools
    'sap_service_discovery',
    'sap_metadata',
    'sap_health_check',
    'system_info',
  ];

• src/services/sap-discovery.ts:205-224 (helper)

  Core helper function to fetch and parse service $metadata XML, used by get-entity-schema to retrieve full entity schema

  private async getServiceMetadata(service: ODataService): Promise<ServiceMetadata> {
    try {
      const destination = await this.sapClient.getDestination({
        type: 'design-time',
        operation: 'discovery',
      });
  
      const response = await executeHttpRequest(destination, {
        method: 'GET',
        url: service.metadataUrl,
        headers: {
          Accept: 'application/xml',
        },
      });
      return this.parseMetadata(response.data, service.odataVersion);
    } catch (error) {
      this.logger.error(`Failed to get metadata for service ${service.id}:`, error);
      throw error;
    }
  }

• src/services/sap-discovery.ts:241-286 (helper)

  Extracts EntityType details including properties, keys, and capabilities from $metadata XML - core logic for entity schema retrieval

  private extractEntityTypes(
    xmlDoc: Document,
    entitySets: Array<{ [key: string]: string | null }>
  ): EntityType[] {
    const entityTypes: EntityType[] = [];
    const nodes = xmlDoc.querySelectorAll('EntityType');
  
    nodes.forEach((node: Element) => {
      const entitySet = entitySets.find(
        entitySet => entitySet.entitytype?.split('.')[1] === node.getAttribute('Name')
      );
      const entityType: EntityType = {
        name: node.getAttribute('Name') || '',
        namespace: node.parentElement?.getAttribute('Namespace') || '',
        entitySet: entitySet?.name,
        creatable: entitySet?.creatable?.toLowerCase() === 'true',
        updatable: entitySet?.updatable?.toLowerCase() === 'true',
        deletable: entitySet?.deletable?.toLowerCase() === 'true',
        addressable: entitySet?.addressable?.toLowerCase() === 'true',
        properties: [],
        navigationProperties: [],
        keys: [],
      };
  
      // Extract properties
      const propNodes = node.querySelectorAll('Property');
      propNodes.forEach((propNode: Element) => {
        entityType.properties.push({
          name: propNode.getAttribute('Name') || '',
          type: propNode.getAttribute('Type') || '',
          nullable: propNode.getAttribute('Nullable') !== 'false',
          maxLength: propNode.getAttribute('MaxLength') ?? undefined,
        });
      });
  
      // Extract keys
      const keyNodes = node.querySelectorAll('Key PropertyRef');
      keyNodes.forEach((keyNode: Element) => {
        entityType.keys.push(keyNode.getAttribute('Name') || '');
      });
  
      entityTypes.push(entityType);
    });
  
    return entityTypes;
  }

• src/mcp-server.ts:78-78 (registration)

  Calls registerDiscoveryTools() on HierarchicalSAPToolRegistry which likely registers get-entity-schema and other discovery tools

  await this.toolRegistry.registerDiscoveryTools();