diff --git a/src/prelude/index.ts b/src/prelude/index.ts
index cf6e5a5..2a01236 100644
--- a/src/prelude/index.ts
+++ b/src/prelude/index.ts
@@ -13,8 +13,9 @@ import { load } from './load'
 import { list } from './list'
 import { math } from './math'
 import { str } from './str'
+import { types } from './types'
 
-export const globals = {
+export const globals: Record<string, any> = {
   dict,
   fs,
   json,
@@ -34,7 +35,6 @@ export const globals = {
       name: Bun.argv[2] || '(shrimp)',
       path: resolve(join('.', Bun.argv[2] ?? ''))
     },
-
   },
 
   // hello
@@ -84,16 +84,6 @@ export const globals = {
   exit: (num: number) => process.exit(num ?? 0),
 
   // type predicates
-  'string?': (v: any) => toValue(v).type === 'string',
-  'number?': (v: any) => toValue(v).type === 'number',
-  'boolean?': (v: any) => toValue(v).type === 'boolean',
-  'array?': (v: any) => toValue(v).type === 'array',
-  'dict?': (v: any) => toValue(v).type === 'dict',
-  'function?': (v: any) => {
-    const t = toValue(v).type
-    return t === 'function' || t === 'native'
-  },
-  'null?': (v: any) => toValue(v).type === 'null',
   'some?': (v: any) => toValue(v).type !== 'null',
 
   // boolean/logic
@@ -212,4 +202,8 @@ export function formatValue(value: Value, inner = false): string {
     default:
       return String(value)
   }
-}
\ No newline at end of file
+}
+
+// add types functions to top-level namespace
+for (const [key, value] of Object.entries(types))
+  globals[key] = value
\ No newline at end of file
diff --git a/src/prelude/tests/types.test.ts b/src/prelude/tests/types.test.ts
new file mode 100644
index 0000000..6a4a587
--- /dev/null
+++ b/src/prelude/tests/types.test.ts
@@ -0,0 +1,143 @@
+import { expect, describe, test } from 'bun:test'
+
+describe('type predicates', () => {
+  test('boolean? checks if value is boolean', async () => {
+    await expect(`boolean? true`).toEvaluateTo(true)
+    await expect(`boolean? false`).toEvaluateTo(true)
+    await expect(`boolean? 42`).toEvaluateTo(false)
+    await expect(`boolean? 'hello'`).toEvaluateTo(false)
+    await expect(`boolean? null`).toEvaluateTo(false)
+    await expect(`boolean? [1 2 3]`).toEvaluateTo(false)
+  })
+
+  test('number? checks if value is number', async () => {
+    await expect(`number? 42`).toEvaluateTo(true)
+    await expect(`number? 3.14`).toEvaluateTo(true)
+    await expect(`number? 0`).toEvaluateTo(true)
+    await expect(`number? -5`).toEvaluateTo(true)
+    await expect(`number? 'hello'`).toEvaluateTo(false)
+    await expect(`number? true`).toEvaluateTo(false)
+    await expect(`number? null`).toEvaluateTo(false)
+  })
+
+  test('string? checks if value is string', async () => {
+    await expect(`string? 'hello'`).toEvaluateTo(true)
+    await expect(`string? ''`).toEvaluateTo(true)
+    await expect(`string? world`).toEvaluateTo(true)
+    await expect(`string? 42`).toEvaluateTo(false)
+    await expect(`string? true`).toEvaluateTo(false)
+    await expect(`string? null`).toEvaluateTo(false)
+    await expect(`string? [1 2 3]`).toEvaluateTo(false)
+  })
+
+  test('array? checks if value is array', async () => {
+    await expect(`array? [1 2 3]`).toEvaluateTo(true)
+    await expect(`array? []`).toEvaluateTo(true)
+    await expect(`array? ['a' 'b']`).toEvaluateTo(true)
+    await expect(`array? [a=1 b=2]`).toEvaluateTo(false)
+    await expect(`array? 42`).toEvaluateTo(false)
+    await expect(`array? 'hello'`).toEvaluateTo(false)
+    await expect(`array? null`).toEvaluateTo(false)
+  })
+
+  test('list? is alias for array?', async () => {
+    await expect(`list? [1 2 3]`).toEvaluateTo(true)
+    await expect(`list? []`).toEvaluateTo(true)
+    await expect(`list? [a=1 b=2]`).toEvaluateTo(false)
+  })
+
+  test('dict? checks if value is dict', async () => {
+    await expect(`dict? [a=1 b=2]`).toEvaluateTo(true)
+    await expect(`dict? [=]`).toEvaluateTo(true)
+    await expect(`dict? [1 2 3]`).toEvaluateTo(false)
+    await expect(`dict? []`).toEvaluateTo(false)
+    await expect(`dict? 42`).toEvaluateTo(false)
+    await expect(`dict? 'hello'`).toEvaluateTo(false)
+  })
+
+  test('function? checks if value is function', async () => {
+    await expect(`
+      my-fn = do x: x * 2 end
+      function? my-fn
+    `).toEvaluateTo(true)
+    await expect(`function? inc`).toEvaluateTo(true)
+    await expect(`function? list.map`).toEvaluateTo(true)
+    await expect(`function? 42`).toEvaluateTo(false)
+    await expect(`function? 'hello'`).toEvaluateTo(false)
+    await expect(`function? [1 2 3]`).toEvaluateTo(false)
+  })
+
+  test('null? checks if value is null', async () => {
+    await expect(`null? null`).toEvaluateTo(true)
+    await expect(`null? 0`).toEvaluateTo(false)
+    await expect(`null? false`).toEvaluateTo(false)
+    await expect(`null? ''`).toEvaluateTo(false)
+    await expect(`null? []`).toEvaluateTo(false)
+  })
+})
+
+describe('type coercion', () => {
+  test('boolean coerces to boolean', async () => {
+    await expect(`boolean true`).toEvaluateTo(true)
+    await expect(`boolean false`).toEvaluateTo(false)
+    await expect(`boolean 1`).toEvaluateTo(true)
+    await expect(`boolean 0`).toEvaluateTo(false)
+    await expect(`boolean 'hello'`).toEvaluateTo(true)
+    await expect(`boolean ''`).toEvaluateTo(false)
+    await expect(`boolean null`).toEvaluateTo(false)
+    await expect(`boolean [1 2 3]`).toEvaluateTo(true)
+  })
+
+  test('number coerces to number', async () => {
+    await expect(`number 42`).toEvaluateTo(42)
+    await expect(`number '42'`).toEvaluateTo(42)
+    await expect(`number '3.14'`).toEvaluateTo(3.14)
+    await expect(`number true`).toEvaluateTo(1)
+    await expect(`number false`).toEvaluateTo(0)
+  })
+
+  test('string coerces to string', async () => {
+    await expect(`string 'hello'`).toEvaluateTo('hello')
+    await expect(`string 42`).toEvaluateTo('42')
+    await expect(`string true`).toEvaluateTo('true')
+    await expect(`string false`).toEvaluateTo('false')
+    await expect(`string null`).toEvaluateTo('null')
+  })
+})
+
+describe('type predicates in conditionals', () => {
+  test('using type predicates in if statements', async () => {
+    await expect(`
+      x = 42
+      if (number? x):
+        'is-num'
+      else:
+        'not-num'
+      end
+    `).toEvaluateTo('is-num')
+  })
+
+  test('filtering by type', async () => {
+    await expect(`
+      items = [1 'hello' 2 'world' 3]
+      list.filter items number?
+    `).toEvaluateTo([1, 2, 3])
+  })
+
+  test('filtering strings', async () => {
+    await expect(`
+      items = [1 'hello' 2 'world' 3]
+      list.filter items string?
+    `).toEvaluateTo(['hello', 'world'])
+  })
+
+  test('checking for functions', async () => {
+    await expect(`
+      double = do x: x * 2 end
+      not-fn = 42
+      is-fn = function? double
+      is-not-fn = function? not-fn
+      is-fn and (not is-not-fn)
+    `).toEvaluateTo(true)
+  })
+})
diff --git a/src/prelude/types.ts b/src/prelude/types.ts
new file mode 100644
index 0000000..a92c4c0
--- /dev/null
+++ b/src/prelude/types.ts
@@ -0,0 +1,22 @@
+import { toValue } from 'reefvm'
+
+export const types = {
+  'boolean?': (v: any) => toValue(v).type === 'boolean',
+  boolean: (v: any) => Boolean(v),
+
+  'number?': (v: any) => toValue(v).type === 'number',
+  number: (v: any) => Number(v),
+
+  'string?': (v: any) => toValue(v).type === 'string',
+  string: (v: any) => String(v),
+
+
+  'array?': (v: any) => toValue(v).type === 'array',
+  'list?': (v: any) => toValue(v).type === 'array',
+
+  'dict?': (v: any) => toValue(v).type === 'dict',
+
+  'function?': (v: any) => ['function', 'native'].includes(toValue(v).type),
+
+  'null?': (v: any) => toValue(v).type === 'null',
+}