diff --git a/package.json b/package.json
index 9dce1346..7e80cc8e 100644
--- a/package.json
+++ b/package.json
@@ -15,12 +15,13 @@
     "lint": "npx eslint 'ts/**/*.{js,ts}' --fix",
     "test": "npm run build:jsonschema && jest",
     "test:cover": "npm run build:jsonschema && jest --coverage",
-    "build": "npm run build:jsonschema && npm run build:jsonld && npm run build:ts && npm run build:py && npm run build:r",
+    "build": "npm run build:jsonschema && npm run build:jsonld && npm run build:ts && npm run build:py && npm run build:r && npm run build:dist",
     "build:jsonschema": "ts-node ts/schema.ts",
     "build:jsonld": "ts-node ts/bindings/jsonld.ts",
-    "build:ts": "ts-node ts/bindings/typescript.ts && microbundle --tsconfig tsconfig.lib.json && cp public/*.schema.json dist && cp public/*.jsonld dist",
+    "build:ts": "ts-node ts/bindings/typescript.ts",
     "build:py": "ts-node ts/bindings/python.ts",
     "build:r": "ts-node ts/bindings/r.ts",
+    "build:dist": "microbundle --tsconfig tsconfig.lib.json && cp public/*.schema.json dist && cp public/*.jsonld dist",
     "docs": "npm run docs:readme && npm run docs:build && npm run docs:api",
     "docs:readme": "markdown-toc -i --maxdepth=4 README.md",
     "docs:build": "ts-node ts/docs.ts",
diff --git a/schema/Array.schema.yaml b/schema/Array.schema.yaml
new file mode 100644
index 00000000..1b6d8217
--- /dev/null
+++ b/schema/Array.schema.yaml
@@ -0,0 +1,4 @@
+title: Array
+'@id': stencila:Array
+description: A value comprised of several other values.
+type: array
diff --git a/schema/Boolean.schema.yaml b/schema/Boolean.schema.yaml
new file mode 100644
index 00000000..bcd72861
--- /dev/null
+++ b/schema/Boolean.schema.yaml
@@ -0,0 +1,4 @@
+title: Boolean
+'@id': schema:Boolean
+description: A value that is either true or false
+type: boolean
diff --git a/schema/Null.schema.yaml b/schema/Null.schema.yaml
new file mode 100644
index 00000000..84a31c1d
--- /dev/null
+++ b/schema/Null.schema.yaml
@@ -0,0 +1,4 @@
+title: 'Null'
+'@id': stencila:Null
+description: The null value
+type: 'null'
diff --git a/schema/Number.schema.yaml b/schema/Number.schema.yaml
new file mode 100644
index 00000000..81f8648a
--- /dev/null
+++ b/schema/Number.schema.yaml
@@ -0,0 +1,4 @@
+title: Number
+'@id': schema:Number
+description: A value that is a number
+type: number
diff --git a/schema/Object.schema.yaml b/schema/Object.schema.yaml
new file mode 100644
index 00000000..14e50b26
--- /dev/null
+++ b/schema/Object.schema.yaml
@@ -0,0 +1,4 @@
+title: Object
+'@id': stencila:Object
+description: A value comprised of keyed values.
+type: object
diff --git a/schema/Text.schema.yaml b/schema/Text.schema.yaml
new file mode 100644
index 00000000..c2f173e2
--- /dev/null
+++ b/schema/Text.schema.yaml
@@ -0,0 +1,4 @@
+title: Text
+'@id': schema:Text
+description: A value comprised of a string of characters
+type: string
diff --git a/ts/bindings/python.ts b/ts/bindings/python.ts
index ee028f80..2a7c5ea1 100644
--- a/ts/bindings/python.ts
+++ b/ts/bindings/python.ts
@@ -7,7 +7,7 @@ import fs from 'fs-extra'
 import path from 'path'
 import {
   autogeneratedHeader,
-  filterTypeSchemas,
+  filterInterfaceSchemas,
   filterUnionSchemas,
   getSchemaProperties,
   readSchemas,
@@ -39,7 +39,7 @@ async function build(): Promise<void> {
   const schemas = await readSchemas()
 
   globals = []
-  const classesCode = filterTypeSchemas(schemas)
+  const classesCode = filterInterfaceSchemas(schemas)
     .map(classGenerator)
     .join('\n\n')
   const unionsCode = filterUnionSchemas(schemas)
diff --git a/ts/bindings/r.ts b/ts/bindings/r.ts
index 726e27be..7cab21dd 100644
--- a/ts/bindings/r.ts
+++ b/ts/bindings/r.ts
@@ -6,7 +6,7 @@ import fs from 'fs-extra'
 import path from 'path'
 import {
   autogeneratedHeader,
-  filterTypeSchemas,
+  filterInterfaceSchemas,
   filterUnionSchemas,
   getSchemaProperties,
   readSchemas,
@@ -25,7 +25,7 @@ if (module.parent === null) build()
 async function build(): Promise<void> {
   const schemas = await readSchemas()
 
-  const classesCode = filterTypeSchemas(schemas)
+  const classesCode = filterInterfaceSchemas(schemas)
     .map(classGenerator)
     .join('\n')
   const unionsCode = filterUnionSchemas(schemas)
diff --git a/ts/bindings/typescript.test.ts b/ts/bindings/typescript.test.ts
index 6f0db14c..5d1d406c 100644
--- a/ts/bindings/typescript.test.ts
+++ b/ts/bindings/typescript.test.ts
@@ -13,12 +13,12 @@ import * as typescript from 'typescript'
 import { schema, snapshot } from '../__tests__/helpers'
 import {
   generateTypeDefinitions,
-  typeGenerator,
+  interfaceGenerator,
   unionGenerator
 } from './typescript'
 
 test('generators', async () => {
-  expect(typeGenerator(await schema('Person.schema.json'))).toMatchFile(
+  expect(interfaceGenerator(await schema('Person.schema.json'))).toMatchFile(
     snapshot(__dirname, 'Person.ts')
   )
 
diff --git a/ts/bindings/typescript.ts b/ts/bindings/typescript.ts
index 77db5e8c..98ec3134 100644
--- a/ts/bindings/typescript.ts
+++ b/ts/bindings/typescript.ts
@@ -8,7 +8,7 @@ import path from 'path'
 import prettier from 'prettier'
 import {
   autogeneratedHeader,
-  filterTypeSchemas,
+  filterInterfaceSchemas,
   filterUnionSchemas,
   getSchemaProperties,
   readSchemas,
@@ -35,8 +35,8 @@ const prettify = async (contents: string): Promise<string> => {
 export const generateTypeDefinitions = async (): Promise<string> => {
   const schemas = await readSchemas()
 
-  const typesCode = filterTypeSchemas(schemas)
-    .map(typeGenerator)
+  const interfacesCode = filterInterfaceSchemas(schemas)
+    .map(interfaceGenerator)
     .join('')
 
   const unionsCode = filterUnionSchemas(schemas)
@@ -57,7 +57,7 @@ const compact = <O extends object>(o: O): O =>
 
 ${typesInterface(schemas)}
 
-${typesCode}
+${interfacesCode}
 
 ${unionsCode}
 `
@@ -74,14 +74,32 @@ ${unionsCode}
  */
 export const typesInterface = (schemas: Schema[]): string => {
   return `export interface Types {\n${schemas
-    .map(({ title }) => `  ${title}: ${title}`)
+    .map(({ title }) => `  ${title}: ${titleToType(title ?? '')}`)
     .join('\n')}\n}`
 }
 
+/**
+ * Convert the `title` of a JSON Schema to the name of a Typescript
+ * type, including the interfaces and unions generated below.
+ */
+export const titleToType = (title: string): string => {
+  switch (title) {
+    case 'Null':
+    case 'Boolean':
+    case 'Number':
+    case 'Object':
+      return title.toLowerCase()
+    case 'Array':
+      return 'Array<any>'
+    default:
+      return title
+  }
+}
+
 /**
  * Generate a `interface` and a factory function for each type.
  */
-export const typeGenerator = (schema: Schema): string => {
+export const interfaceGenerator = (schema: Schema): string => {
   const {
     title = 'Undefined',
     extends: parent,
@@ -171,7 +189,7 @@ const docComment = (description?: string, tags: string[] = []): string => {
 }
 
 /**
- * Convert a schema definition to a Typescript type
+ * Convert a JSON Schema definition to a Typescript type
  */
 const schemaToType = (schema: Schema): string => {
   const { type, anyOf, allOf, $ref } = schema
@@ -193,7 +211,7 @@ const schemaToType = (schema: Schema): string => {
 }
 
 /**
- * Convert a schema `$ref` (reference) to a Typescript type
+ * Convert a JSON Schema `$ref` (reference) to a Typescript type
  *
  * Assume that any `$ref`s refer to a type defined in the file.
  */
@@ -202,7 +220,7 @@ const $refToType = ($ref: string): string => {
 }
 
 /**
- * Convert a schema with the `anyOf` property to a Typescript `Union` type.
+ * Convert a JSON Schema with the `anyOf` property to a Typescript `Union` type.
  */
 const anyOfToType = (anyOf: Schema[]): string => {
   const types = anyOf
@@ -217,7 +235,7 @@ const anyOfToType = (anyOf: Schema[]): string => {
 }
 
 /**
- * Convert a schema with the `allOf` property to a Typescript type.
+ * Convert a JSON Schema with the `allOf` property to a Typescript type.
  *
  * If the `allOf` is singular then just use that (this usually arises
  * because the `allOf` is used for a property with a `$ref`). Otherwise,
@@ -231,7 +249,7 @@ const allOfToType = (allOf: Schema[]): string => {
 }
 
 /**
- * Convert a schema with the `array` property to a Typescript `Array` type.
+ * Convert a JSON Schema with the `array` property to a Typescript `Array` type.
  *
  * Uses the more explicity `Array<>` syntax over the shorter`[]` syntax
  * because the latter necessitates the use of, sometime superfluous, parentheses.
@@ -246,7 +264,7 @@ const arrayToType = (schema: Schema): string => {
 }
 
 /**
- * Convert a schema with the `enum` property to Typescript "or values".
+ * Convert a JSON Schema with the `enum` property to Typescript "or values".
  */
 export const enumToType = (enu: (string | number)[]): string => {
   return enu
@@ -305,8 +323,9 @@ export const generateTypeMaps = async (): Promise<string> => {
 }
 
 /** Generate Type Definitions and Type Maps files */
-export const build = async (): Promise<unknown> => {
-  return generateTypeDefinitions().then(generateTypeMaps)
+export const build = async (): Promise<void> => {
+  await generateTypeDefinitions()
+  await generateTypeMaps()
 }
 
 /**
diff --git a/ts/helpers.ts b/ts/helpers.ts
index 9de9f9cb..7a68b006 100644
--- a/ts/helpers.ts
+++ b/ts/helpers.ts
@@ -34,13 +34,27 @@ export async function readSchemas(
 }
 
 /**
- * Get the 'type' schemas (i.e. not union schema, not property schemas) which are
- * usually translated into classes or similar for the language.
+ * Is a schema for a primitive type.
+ */
+export function isPrimitiveSchema(schema: Schema): boolean {
+  return schema.properties === undefined && schema.anyOf === undefined
+}
+
+/**
+ * Get the 'primitive' schemas
+ */
+export function filterPrimitiveSchemas(schemas: Schema[]): Schema[] {
+  return schemas.filter(isPrimitiveSchema)
+}
+
+/**
+ * Get the 'interface' schemas (i.e. not union schema, not property schemas) which are
+ * usually translated into `interface`s, `class`es or similar for the language.
  *
  * Types are sorted topologically so that schemas come before
  * any of their descendants.
  */
-export function filterTypeSchemas(schemas: Schema[]): Schema[] {
+export function filterInterfaceSchemas(schemas: Schema[]): Schema[] {
   const types = schemas.filter(schema => schema.properties !== undefined)
   const map = new Map(schemas.map(schema => [schema.title, schema]))
 
diff --git a/ts/util/node-type.test.ts b/ts/util/node-type.test.ts
index fe2db6a9..abcb60f4 100644
--- a/ts/util/node-type.test.ts
+++ b/ts/util/node-type.test.ts
@@ -1,13 +1,13 @@
 import { nodeType } from './node-type'
 
 test('nodeType', () => {
-  expect(nodeType(null)).toBe('null')
-  expect(nodeType(true)).toBe('boolean')
-  expect(nodeType(false)).toBe('boolean')
-  expect(nodeType(42)).toBe('number')
-  expect(nodeType(3.14)).toBe('number')
-  expect(nodeType('str')).toBe('string')
-  expect(nodeType([])).toBe('array')
-  expect(nodeType({})).toBe('object')
+  expect(nodeType(null)).toBe('Null')
+  expect(nodeType(true)).toBe('Boolean')
+  expect(nodeType(false)).toBe('Boolean')
+  expect(nodeType(42)).toBe('Number')
+  expect(nodeType(3.14)).toBe('Number')
+  expect(nodeType('str')).toBe('Text')
+  expect(nodeType([])).toBe('Array')
+  expect(nodeType({})).toBe('Object')
   expect(nodeType({ type: 'Person' })).toBe('Person')
 })
diff --git a/ts/util/node-type.ts b/ts/util/node-type.ts
index 84949fd8..79acd034 100644
--- a/ts/util/node-type.ts
+++ b/ts/util/node-type.ts
@@ -1,16 +1,17 @@
-import { Node } from '../types'
+import { Types, Node } from '../types'
 import { isEntity } from './guards'
 
 /**
  * Get the type of a node
+ *
  * @param {Node} node The schema node to get the type for
  */
-export const nodeType = (node: Node): string => {
-  if (node === null) return 'null'
-  if (typeof node === 'boolean') return 'boolean'
-  if (typeof node === 'number') return 'number'
-  if (typeof node === 'string') return 'string'
-  if (Array.isArray(node)) return 'array'
+export const nodeType = (node: Node): keyof Types => {
+  if (node === null) return 'Null'
+  if (typeof node === 'boolean') return 'Boolean'
+  if (typeof node === 'number') return 'Number'
+  if (typeof node === 'string') return 'Text'
+  if (Array.isArray(node)) return 'Array'
   if (isEntity(node)) return node.type
-  return typeof node
+  return 'Object'
 }