diff --git a/src/Typegen.test.ts b/src/Typegen.test.ts
index e34640c..92e081e 100644
--- a/src/Typegen.test.ts
+++ b/src/Typegen.test.ts
@@ -248,6 +248,206 @@ describe('fromCli', () => {
     expect(output).toContain('output: string')
   })
 
+  test('invalid property keys are quoted', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        'dry-run': z.boolean(),
+        nested: z.object({ 'output-file': z.string().optional() }),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    expect(output).toContain('"dry-run": boolean')
+    expect(output).toContain('nested: { "output-file"?: string | undefined }')
+  })
+
+  test('tuple schemas render as TypeScript tuples', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        point: z.tuple([z.number(), z.number()]),
+        range: z.tuple([z.string()]).rest(z.number()),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    expect(output).toContain('point: [number, number]')
+    expect(output).toContain('range: [string, ...number[]]')
+  })
+
+  test('record and catchall schemas render indexable types', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        counts: z.record(z.string(), z.number()),
+        flags: z.object({ required: z.boolean() }).catchall(z.string()),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    expect(output).toContain('counts: Record<string, number>')
+    expect(output).toContain('flags: { required: boolean } & Record<string, string | boolean>')
+  })
+
+  test('catchall schemas widen record values for incompatible fixed properties', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        flags: z.object({ required: z.boolean() }).catchall(z.string()),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    // TypeScript cannot express "only unknown extra keys" with a plain index signature.
+    // Widening keeps declared properties assignable while still preserving an indexable shape.
+    expect(output).toContain('flags: { required: boolean } & Record<string, string | boolean>')
+  })
+
+  test('array item intersections are parenthesized', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        items: z.array(z.object({ id: z.number() }).catchall(z.string())),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    expect(output).toContain('items: ({ id: number } & Record<string, string | number>)[]')
+  })
+
+  test('partial enum records render optional keys', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        counts: z.partialRecord(z.enum(['open', 'closed']), z.number()),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    expect(output).toContain('counts: Partial<Record<"open" | "closed", number>>')
+  })
+
+  test('partial literal records render optional keys', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        counts: z.partialRecord(z.literal('open'), z.number()),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    expect(output).toContain('counts: Partial<Record<"open", number>>')
+  })
+
+  test('partial numeric literal records render optional keys', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        counts: z.partialRecord(z.literal(1), z.number()),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    expect(output).toContain('counts: Partial<Record<1, number>>')
+  })
+
+  test('partial union records render optional keys', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        counts: z.partialRecord(z.union([z.literal('open'), z.literal('closed')]), z.number()),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    expect(output).toContain('counts: Partial<Record<"open" | "closed", number>>')
+  })
+
+  test('mixed finite and open key records render open keys', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        counts: z.partialRecord(z.union([z.literal('open'), z.string()]), z.number()),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    expect(output).toContain('counts: Record<"open" | string, number>')
+  })
+
+  test('required enum records render required keys', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        counts: z.record(z.enum(['open', 'closed']), z.number()),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    expect(output).toContain('counts: Record<"open" | "closed", number>')
+  })
+
+  test('required literal records render required keys', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        counts: z.record(z.literal('open'), z.number()),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    expect(output).toContain('counts: Record<"open", number>')
+  })
+
+  test('required numeric literal records render required keys', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        counts: z.record(z.literal(1), z.number()),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    expect(output).toContain('counts: Record<1, number>')
+  })
+
+  test('required union records render required keys', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        counts: z.record(z.union([z.literal('open'), z.literal('closed')]), z.number()),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    expect(output).toContain('counts: Record<"open" | "closed", number>')
+  })
+
+  test('required numeric union records render required keys', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        counts: z.record(z.union([z.literal(1), z.literal(2)]), z.number()),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    expect(output).toContain('counts: Record<1 | 2, number>')
+  })
+
+  test('record with unknown property names falls back to string keys', () => {
+    const cli = Cli.create('test').command('create', {
+      options: z.object({
+        counts: z.record(z.any(), z.number()),
+      }),
+      run: () => ({}),
+    })
+
+    const output = Typegen.fromCli(cli)
+    expect(output).toContain('counts: Record<string, number>')
+  })
+
   test('mixed top-level and grouped commands', () => {
     const cli = Cli.create('test')
     cli.command('ping', { run: () => ({}) })
diff --git a/src/Typegen.ts b/src/Typegen.ts
index 0903fe6..4469a07 100644
--- a/src/Typegen.ts
+++ b/src/Typegen.ts
@@ -88,28 +88,144 @@ function resolveType(
     case 'null':
       return 'null'
     case 'array': {
+      const prefixItems = schema.prefixItems as Record<string, unknown>[] | undefined
+      if (prefixItems) {
+        const items = prefixItems.map((item) => resolveType(item, defs))
+        const rest = schema.items as Record<string, unknown> | undefined
+        if (rest) items.push(`...${arrayToType(resolveType(rest, defs))}`)
+        return `[${items.join(', ')}]`
+      }
+
       const items = schema.items as Record<string, unknown> | undefined
       const itemType = items ? resolveType(items, defs) : 'unknown'
-      return itemType.includes(' | ') ? `(${itemType})[]` : `${itemType}[]`
-    }
-    case 'object': {
-      const properties = schema.properties as Record<string, Record<string, unknown>> | undefined
-      if (!properties || Object.keys(properties).length === 0) return '{}'
-      const required = new Set((schema.required as string[] | undefined) ?? [])
-      const entries = Object.entries(properties).map(([key, value]) => {
-        const type = resolveType(value, defs)
-        if (required.has(key)) return `${propertyKey(key)}: ${type}`
-        return `${propertyKey(key)}?: ${type} | undefined`
-      })
-      return `{ ${entries.join('; ')} }`
+      return arrayToType(itemType)
     }
+    case 'object':
+      return objectToType(schema, defs)
     default:
       return 'unknown'
   }
 }
 
-function propertyKey(key: string) {
-  return /^[A-Za-z_$][\w$]*$/.test(key) ? key : JSON.stringify(key)
+function arrayToType(type: string): string {
+  return type.includes(' | ') || type.includes(' & ') ? `(${type})[]` : `${type}[]`
+}
+
+function objectToType(
+  schema: Record<string, unknown>,
+  defs: Record<string, Record<string, unknown>>,
+): string {
+  const properties = schema.properties as Record<string, Record<string, unknown>> | undefined
+  const required = new Set((schema.required as unknown[] | undefined) ?? [])
+  const entries = Object.entries(properties ?? {}).map(([key, value]) =>
+    propertyToType(key, value, required, defs),
+  )
+  const object = entries.length > 0 ? `{ ${entries.join('; ')} }` : '{}'
+  const additional = schema.additionalProperties as Record<string, unknown> | boolean | undefined
+
+  if (!additional) return object
+  const value = typeof additional === 'object' ? resolveType(additional, defs) : 'unknown'
+  const propertyNames = schema.propertyNames as Record<string, unknown> | undefined
+  const key = recordKeyToType(propertyNames, defs)
+  const propertyValues = Object.entries(properties ?? {}).map(([key, value]) =>
+    propertyValueToType(key, value, required, defs),
+  )
+  const recordValue = unionTypes([value, ...propertyValues])
+  const record = recordToType(key, recordValue, propertyNames, required)
+  if (entries.length === 0) return record
+  return `${object} & ${record}`
+}
+
+function recordKeyToType(
+  schema: Record<string, unknown> | undefined,
+  defs: Record<string, Record<string, unknown>>,
+): string {
+  if (!schema) return 'string'
+  const type = resolveType(schema, defs)
+  if (type === 'unknown') return 'string'
+  return type
+}
+
+function recordToType(
+  key: string,
+  value: string,
+  propertyNames: Record<string, unknown> | undefined,
+  required: Set<unknown>,
+): string {
+  const record = `Record<${key}, ${value}>`
+  const keys = propertyNames ? finitePropertyNames(propertyNames) : undefined
+  if (!keys) return record
+
+  if (keys.every((key) => required.has(key))) return record
+  return `Partial<${record}>`
+}
+
+function finitePropertyNames(schema: Record<string, unknown>): unknown[] | undefined {
+  if ('const' in schema) return [schema.const]
+  if (schema.enum) return schema.enum as unknown[]
+  if (schema.anyOf) {
+    const keys = (schema.anyOf as Record<string, unknown>[]).map(finitePropertyNames)
+    if (keys.every((key) => key)) return keys.flatMap((key) => key)
+  }
+  return undefined
+}
+
+function propertyValueToType(
+  key: string,
+  schema: Record<string, unknown>,
+  required: Set<unknown>,
+  defs: Record<string, Record<string, unknown>>,
+): string {
+  const type = resolveType(schema, defs)
+  if (required.has(key)) return type
+  return unionTypes([type, 'undefined'])
+}
+
+function unionTypes(types: string[]): string {
+  const entries = types.flatMap(splitUnionType)
+  if (entries.includes('unknown')) return 'unknown'
+  return [...new Set(entries)].join(' | ')
+}
+
+function splitUnionType(type: string): string[] {
+  const parts: string[] = []
+  let depth = 0
+  let quote = ''
+  let start = 0
+
+  for (let i = 0; i < type.length; i++) {
+    const char = type[i]
+    if (quote) {
+      if (char === '\\') i++
+      else if (char === quote) quote = ''
+    } else if (char === '"' || char === "'") quote = char
+    else if (char === '(' || char === '[' || char === '{' || char === '<') depth++
+    else if (char === ')' || char === ']' || char === '}' || char === '>') depth--
+    else if (depth === 0 && type.slice(i, i + 3) === ' | ') {
+      parts.push(type.slice(start, i))
+      start = i + 3
+      i += 2
+    }
+  }
+
+  parts.push(type.slice(start))
+  return parts
+}
+
+function propertyToType(
+  key: string,
+  schema: Record<string, unknown>,
+  required: Set<unknown>,
+  defs: Record<string, Record<string, unknown>>,
+): string {
+  const type = resolveType(schema, defs)
+  if (required.has(key)) return `${propertyKey(key)}: ${type}`
+  return `${propertyKey(key)}?: ${type} | undefined`
+}
+
+function propertyKey(key: string): string {
+  if (/^[$A-Z_a-z][$\w]*$/.test(key)) return key
+  return JSON.stringify(key)
 }
 
 function isStream(command: Cli.CommandDefinition<any, any, any, any, any, any>) {