diff --git a/CLAUDE.md b/CLAUDE.md
index 31440d8..0098761 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -137,37 +137,55 @@ Array format features:
 - Function params as string arrays: `["MAKE_FUNCTION", ["x", "y=10"], ".body"]`
 - See `tests/programmatic.test.ts` and `examples/programmatic.ts` for examples
 
-### Native Function Registration
+### Native Function Registration and Global Values
 
 **Option 1**: Pass to `run()` or `VM` constructor (convenience)
 ```typescript
 const result = await run(bytecode, {
   add: (a: number, b: number) => a + b,
-  greet: (name: string) => `Hello, ${name}!`
+  greet: (name: string) => `Hello, ${name}!`,
+  pi: 3.14159,
+  config: { debug: true, port: 8080 }
 })
 
 // Or with VM constructor
-const vm = new VM(bytecode, { add, greet })
+const vm = new VM(bytecode, { add, greet, pi, config })
 ```
 
-**Option 2**: Register with `vm.registerFunction()` (manual)
+**Option 2**: Set values with `vm.set()` (manual)
 ```typescript
 const vm = new VM(bytecode)
-vm.registerFunction('add', (a: number, b: number) => a + b)
+
+// Set functions (auto-wrapped to native functions)
+vm.set('add', (a: number, b: number) => a + b)
+
+// Set any other values (auto-converted to ReefVM Values)
+vm.set('pi', 3.14159)
+vm.set('config', { debug: true, port: 8080 })
+
 await vm.run()
 ```
 
-**Option 3**: Register Value-based functions (for direct Value access)
+**Option 3**: Set Value-based functions with `vm.setValueFunction()` (advanced)
+
+For functions that work directly with ReefVM Value types:
+
 ```typescript
-vm.registerValueFunction('customOp', (a: Value, b: Value): Value => {
+const vm = new VM(bytecode)
+
+// Set Value-based function (no wrapping, works directly with Values)
+vm.setValueFunction('customOp', (a: Value, b: Value): Value => {
   return toValue(toNumber(a) + toNumber(b))
 })
+
+await vm.run()
 ```
 
 Auto-wrapping handles:
-- Value ↔ native type conversion (`fromValue`/`toValue`)
+- Functions: wrapped as native functions with Value ↔ native type conversion
 - Sync and async functions
 - Arrays, objects, primitives, null, RegExp
+- All values converted via `toValue()`
 
 ### Calling Functions from TypeScript
 
diff --git a/GUIDE.md b/GUIDE.md
index 99b8073..a8e5683 100644
--- a/GUIDE.md
+++ b/GUIDE.md
@@ -662,18 +662,18 @@ const vm = new VM(bytecode, { add, greet })
 **Method 2**: Register after construction
 ```typescript
 const vm = new VM(bytecode)
-vm.registerFunction('add', (a: number, b: number) => a + b)
+vm.set('add', (a: number, b: number) => a + b)
 await vm.run()
 ```
 
 **Method 3**: Value-based functions (for full control)
 ```typescript
-vm.registerValueFunction('customOp', (a: Value, b: Value): Value => {
+vm.setValueFunction('customOp', (a: Value, b: Value): Value => {
   return { type: 'number', value: toNumber(a) + toNumber(b) }
 })
 ```
 
-**Auto-wrapping**: `registerFunction` automatically converts between native TypeScript types and ReefVM Value types. Both sync and async functions work.
+**Auto-wrapping**: `vm.set()` automatically converts between native TypeScript types and ReefVM Value types. Both sync and async functions work.
 
 **Usage in bytecode**:
 ```
@@ -702,12 +702,12 @@ CALL                  ; → "Hi, Alice!"
 
 ```typescript
 // Basic @named - collects all named args
-vm.registerFunction('greet', (atNamed: any = {}) => {
+vm.set('greet', (atNamed: any = {}) => {
   return `Hello, ${atNamed.name || 'World'}!`
 })
 
 // Mixed positional and @named
-vm.registerFunction('configure', (name: string, atOptions: any = {}) => {
+vm.set('configure', (name: string, atOptions: any = {}) => {
   return {
     name,
     debug: atOptions.debug || false,
diff --git a/SPEC.md b/SPEC.md
index acc01d1..1aa2118 100644
--- a/SPEC.md
+++ b/SPEC.md
@@ -622,7 +622,7 @@ const vm = new VM(bytecode, {
 })
 
 // Or after construction:
-vm.registerFunction('multiply', (a: number, b: number) => a * b)
+vm.set('multiply', (a: number, b: number) => a * b)
 ```
 
 **Usage in Bytecode**:
@@ -637,9 +637,9 @@ CALL              ; Call it like any other function
 
 **Native Function Types**:
 
-1. **Auto-wrapped functions** (via `registerFunction`): Accept and return native TypeScript types (number, string, boolean, array, object, etc.). The VM automatically converts between Value types and native types.
+1. **Auto-wrapped functions** (via `vm.set()`): Accept and return native TypeScript types (number, string, boolean, array, object, etc.). The VM automatically converts between Value types and native types.
 
-2. **Value-based functions** (via `registerValueFunction`): Accept and return `Value` types directly for full control over type handling.
+2. **Value-based functions** (via `vm.setValueFunction()`): Accept and return `Value` types directly for full control over type handling.
 
 **Auto-Wrapping Behavior**:
 - Parameters: `Value` → native type (number, string, boolean, array, object, null, RegExp)
@@ -655,27 +655,27 @@ CALL              ; Call it like any other function
 **Examples**:
 ```typescript
 // Auto-wrapped native types
-vm.registerFunction('add', (a: number, b: number) => a + b)
-vm.registerFunction('greet', (name: string) => `Hello, ${name}!`)
-vm.registerFunction('range', (n: number) => Array.from({ length: n }, (_, i) => i))
+vm.set('add', (a: number, b: number) => a + b)
+vm.set('greet', (name: string) => `Hello, ${name}!`)
+vm.set('range', (n: number) => Array.from({ length: n }, (_, i) => i))
 
 // With defaults
-vm.registerFunction('greet', (name: string, greeting = 'Hello') => {
+vm.set('greet', (name: string, greeting = 'Hello') => {
   return `${greeting}, ${name}!`
 })
 
 // Variadic functions
-vm.registerFunction('sum', (...nums: number[]) => {
+vm.set('sum', (...nums: number[]) => {
   return nums.reduce((acc, n) => acc + n, 0)
 })
 
 // Value-based for custom logic
-vm.registerValueFunction('customOp', (a: Value, b: Value): Value => {
+vm.setValueFunction('customOp', (a: Value, b: Value): Value => {
   return { type: 'number', value: toNumber(a) + toNumber(b) }
 })
 
 // Async functions
-vm.registerFunction('fetchData', async (url: string) => {
+vm.set('fetchData', async (url: string) => {
   const response = await fetch(url)
   return response.json()
 })
@@ -912,10 +912,10 @@ const vm = new VM(bytecode, {
 })
 
 // Or register after construction
-vm.registerFunction('multiply', (a: number, b: number) => a * b)
+vm.set('multiply', (a: number, b: number) => a * b)
 
 // Or use Value-based functions
-vm.registerValueFunction('customOp', (a: Value, b: Value): Value => {
+vm.setValueFunction('customOp', (a: Value, b: Value): Value => {
   return { type: 'number', value: toNumber(a) + toNumber(b) }
 })
 
diff --git a/examples/native.ts b/examples/native.ts
index 70d3e0d..f1c9b5b 100644
--- a/examples/native.ts
+++ b/examples/native.ts
@@ -9,7 +9,7 @@ const bytecode = toBytecode(`
 
 const vm = new VM(bytecode)
 
-vm.registerFunction('print', (...args: Value[]): Value => {
+vm.set('print', (...args: Value[]): Value => {
   console.log(...args.map(toString))
   return toNull()
 })
diff --git a/src/index.ts b/src/index.ts
index ce72660..40b5dfd 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,9 +1,9 @@
 import type { Bytecode } from "./bytecode"
-import type { Value, TypeScriptFunction } from "./value"
+import type { Value } from "./value"
 import { VM } from "./vm"
 
-export async function run(bytecode: Bytecode, functions?: Record<string, TypeScriptFunction>): Promise<Value> {
-  const vm = new VM(bytecode, functions)
+export async function run(bytecode: Bytecode, globals?: Record<string, any>): Promise<Value> {
+  const vm = new VM(bytecode, globals)
   return await vm.run()
 }
 
diff --git a/src/vm.ts b/src/vm.ts
index 7b8cd24..5d8b9d0 100644
--- a/src/vm.ts
+++ b/src/vm.ts
@@ -19,15 +19,15 @@ export class VM {
   labels: Map<number, string> = new Map()
   nativeFunctions: Map<string, NativeFunction> = new Map()
 
-  constructor(bytecode: Bytecode, globalFunctions?: Record<string, TypeScriptFunction>) {
+  constructor(bytecode: Bytecode, globals?: Record<string, any>) {
     this.instructions = bytecode.instructions
     this.constants = bytecode.constants
     this.labels = bytecode.labels || new Map()
     this.scope = new Scope()
 
-    if (globalFunctions) {
-      for (const name of Object.keys(globalFunctions))
-        this.registerFunction(name, globalFunctions[name]!)
+    if (globals) {
+      for (const name of Object.keys(globals ?? {}))
+        this.set(name, globals[name])
 
       this.scope = new Scope(this.scope)
     }
@@ -48,12 +48,18 @@ export class VM {
     }
   }
 
-  registerFunction(name: string, fn: TypeScriptFunction) {
-    const wrapped = isWrapped(fn) ? fn as NativeFunction : wrapNative(this, fn)
-    this.scope.set(name, { type: 'native', fn: wrapped, value: '<function>' })
+  set(name: string, value: any) {
+    if (typeof value === 'function')
+      this.setFunction(name, value)
+    else
+      this.scope.set(name, toValue(value))
   }
 
-  registerValueFunction(name: string, fn: NativeFunction) {
+  setFunction(name: string, fn: TypeScriptFunction) {
+    this.scope.set(name, { type: 'native', fn: wrapNative(this, fn), value: '<function>' })
+  }
+
+  setValueFunction(name: string, fn: NativeFunction) {
     this.scope.set(name, { type: 'native', fn, value: '<function>' })
   }
 
diff --git a/tests/functions-parameter.test.ts b/tests/functions-parameter.test.ts
index 05077dd..bde5575 100644
--- a/tests/functions-parameter.test.ts
+++ b/tests/functions-parameter.test.ts
@@ -104,7 +104,7 @@ describe("functions parameter", () => {
     expect(result).toEqual({ type: 'number', value: 200 })
   })
 
-  test("can combine with manual registerFunction", async () => {
+  test("can combine with manual vm.set", async () => {
     const bytecode = toBytecode(`
       LOAD add
       PUSH 5
@@ -127,7 +127,7 @@ describe("functions parameter", () => {
     })
 
     // Register another function manually
-    vm.registerFunction('subtract', (a: number, b: number) => a - b)
+    vm.set('subtract', (a: number, b: number) => a - b)
 
     const result = await vm.run()
     expect(result).toEqual({ type: 'number', value: 6 })
@@ -224,7 +224,7 @@ describe("functions parameter", () => {
     })
 
     // Override with manual registration
-    vm.registerFunction('getValue', () => 200)
+    vm.set('getValue', () => 200)
 
     const result = await vm.run()
     expect(result).toEqual({ type: 'number', value: 200 })
diff --git a/tests/native.test.ts b/tests/native.test.ts
index 6fb4550..67a8d0f 100644
--- a/tests/native.test.ts
+++ b/tests/native.test.ts
@@ -16,7 +16,7 @@ test("LOAD - basic function call", async () => {
   const vm = new VM(bytecode)
 
   // Register a Value-based function
-  vm.registerValueFunction('add', (a, b) => {
+  vm.setValueFunction('add', (a, b) => {
     return toValue(toNumber(a) + toNumber(b))
   })
 
@@ -36,7 +36,7 @@ test("LOAD - function with string manipulation", async () => {
 
   const vm = new VM(bytecode)
 
-  vm.registerValueFunction('concat', (a, b) => {
+  vm.setValueFunction('concat', (a, b) => {
     const aStr = a.type === 'string' ? a.value : toString(a)
     const bStr = b.type === 'string' ? b.value : toString(b)
     return toValue(aStr + ' ' + bStr)
@@ -57,7 +57,7 @@ test("LOAD - async function", async () => {
 
   const vm = new VM(bytecode)
 
-  vm.registerValueFunction('asyncDouble', async (a) => {
+  vm.setValueFunction('asyncDouble', async (a) => {
     // Simulate async operation
     await new Promise(resolve => setTimeout(resolve, 1))
     return toValue(toNumber(a) * 2)
@@ -77,7 +77,7 @@ test("LOAD - function with no arguments", async () => {
 
   const vm = new VM(bytecode)
 
-  vm.registerValueFunction('getAnswer', () => {
+  vm.setValueFunction('getAnswer', () => {
     return toValue(42)
   })
 
@@ -98,7 +98,7 @@ test("LOAD - function with multiple arguments", async () => {
 
   const vm = new VM(bytecode)
 
-  vm.registerValueFunction('sum', (...args) => {
+  vm.setValueFunction('sum', (...args) => {
     const total = args.reduce((acc, val) => acc + toNumber(val), 0)
     return toValue(total)
   })
@@ -118,7 +118,7 @@ test("LOAD - function returns array", async () => {
 
   const vm = new VM(bytecode)
 
-  vm.registerValueFunction('makeRange', (n) => {
+  vm.setValueFunction('makeRange', (n) => {
     const count = toNumber(n)
     const arr = []
     for (let i = 0; i < count; i++) {
@@ -165,7 +165,7 @@ test("LOAD - using result in subsequent operations", async () => {
 
   const vm = new VM(bytecode)
 
-  vm.registerValueFunction('triple', (n) => {
+  vm.setValueFunction('triple', (n) => {
     return toValue(toNumber(n) * 3)
   })
 
@@ -186,7 +186,7 @@ test("Native function wrapping - basic sync function with native types", async (
   const vm = new VM(bytecode)
 
   // Register with native TypeScript types - auto-wraps!
-  vm.registerFunction('add', (a: number, b: number) => {
+  vm.set('add', (a: number, b: number) => {
     return a + b
   })
 
@@ -206,7 +206,7 @@ test("Native function wrapping - async function with native types", async () =>
   const vm = new VM(bytecode)
 
   // Async native function
-  vm.registerFunction('asyncDouble', async (n: number) => {
+  vm.set('asyncDouble', async (n: number) => {
     await new Promise(resolve => setTimeout(resolve, 1))
     return n * 2
   })
@@ -228,7 +228,7 @@ test("Native function wrapping - string manipulation", async () => {
   const vm = new VM(bytecode)
 
   // Native string function
-  vm.registerFunction('concat', (a: string, b: string) => {
+  vm.set('concat', (a: string, b: string) => {
     return a + ' ' + b
   })
 
@@ -248,7 +248,7 @@ test("Native function wrapping - with default parameters", async () => {
   const vm = new VM(bytecode)
 
   // Function with default parameter (like NOSE commands)
-  vm.registerFunction('ls', (path: string, link = false) => {
+  vm.set('ls', (path: string, link = false) => {
     return link ? `listing ${path} with links` : `listing ${path}`
   })
 
@@ -268,7 +268,7 @@ test("Native function wrapping - returns array", async () => {
   const vm = new VM(bytecode)
 
   // Return native array - auto-converts to Value array
-  vm.registerFunction('makeRange', (n: number) => {
+  vm.set('makeRange', (n: number) => {
     return Array.from({ length: n }, (_, i) => i)
   })
 
@@ -297,7 +297,7 @@ test("Native function wrapping - returns object (becomes dict)", async () => {
   const vm = new VM(bytecode)
 
   // Return plain object - auto-converts to dict
-  vm.registerFunction('makeUser', (name: string, age: number) => {
+  vm.set('makeUser', (name: string, age: number) => {
     return { name, age }
   })
 
@@ -326,11 +326,11 @@ test("Native function wrapping - mixed with manual Value functions", async () =>
 
   const vm = new VM(bytecode)
 
-  // Native function (auto-wrapped by registerFunction)
-  vm.registerFunction('nativeAdd', (n: number) => n + 10)
+  // Native function (auto-wrapped by set)
+  vm.set('nativeAdd', (n: number) => n + 10)
 
-  // Manual Value function (use registerValueFunction)
-  vm.registerValueFunction('manualDouble', (v) => {
+  // Manual Value function (use setValueFunction)
+  vm.setValueFunction('manualDouble', (v) => {
     return toValue(toNumber(v) * 2)
   })
 
@@ -349,7 +349,7 @@ test("Named arguments - basic named arg", async () => {
   `)
 
   const vm = new VM(bytecode)
-  vm.registerFunction('greet', (name: string) => `Hello, ${name}!`)
+  vm.set('greet', (name: string) => `Hello, ${name}!`)
 
   const result = await vm.run()
   expect(result).toEqual({ type: 'string', value: 'Hello, Alice!' })
@@ -367,7 +367,7 @@ test("Named arguments - mixed positional and named", async () => {
   `)
 
   const vm = new VM(bytecode)
-  vm.registerFunction('makeUser', (name: string, age: number) => {
+  vm.set('makeUser', (name: string, age: number) => {
     return { name, age }
   })
 
@@ -393,7 +393,7 @@ test("Named arguments - named takes priority over positional", async () => {
   `)
 
   const vm = new VM(bytecode)
-  vm.registerFunction('add', (a: number, b: number) => a + b)
+  vm.set('add', (a: number, b: number) => a + b)
 
   const result = await vm.run()
   // Named args should be: a=5, b=10
@@ -412,7 +412,7 @@ test("Named arguments - with defaults", async () => {
   `)
 
   const vm = new VM(bytecode)
-  vm.registerFunction('greet', (name: string, greeting = 'Hello') => {
+  vm.set('greet', (name: string, greeting = 'Hello') => {
     return `${greeting}, ${name}!`
   })
 
@@ -433,7 +433,7 @@ test("Named arguments - override defaults with named args", async () => {
   `)
 
   const vm = new VM(bytecode)
-  vm.registerFunction('greet', (name: string, greeting = 'Hello') => {
+  vm.set('greet', (name: string, greeting = 'Hello') => {
     return `${greeting}, ${name}!`
   })
 
@@ -455,7 +455,7 @@ test("Named arguments - with variadic function", async () => {
   `)
 
   const vm = new VM(bytecode)
-  vm.registerFunction('sum', (multiplier: number, ...nums: number[]) => {
+  vm.set('sum', (multiplier: number, ...nums: number[]) => {
     const total = nums.reduce((acc, n) => acc + n, 0)
     return total * multiplier
   })
@@ -466,7 +466,7 @@ test("Named arguments - with variadic function", async () => {
 
 test("Named arguments - works with both wrapped and non-wrapped functions", async () => {
   const bytecode = toBytecode(`
-    ; Test wrapped function (registerFunction)
+    ; Test wrapped function (vm.set)
     LOAD wrappedAdd
     PUSH "a"
     PUSH 5
@@ -477,7 +477,7 @@ test("Named arguments - works with both wrapped and non-wrapped functions", asyn
     CALL
     STORE result1
 
-    ; Test non-wrapped function (registerValueFunction)
+    ; Test non-wrapped function (vm.setValueFunction)
     LOAD valueAdd
     PUSH "a"
     PUSH 3
@@ -497,10 +497,10 @@ test("Named arguments - works with both wrapped and non-wrapped functions", asyn
   const vm = new VM(bytecode)
 
   // Wrapped function - auto-converts types
-  vm.registerFunction('wrappedAdd', (a: number, b: number) => a + b)
+  vm.set('wrappedAdd', (a: number, b: number) => a + b)
 
   // Non-wrapped function - works directly with Values
-  vm.registerValueFunction('valueAdd', (a, b) => {
+  vm.setValueFunction('valueAdd', (a, b) => {
     return toValue(toNumber(a) + toNumber(b))
   })
 
@@ -523,7 +523,7 @@ test("@named pattern - basic atNamed parameter", async () => {
   `)
 
   const vm = new VM(bytecode)
-  vm.registerFunction('greet', (atNamed: any = {}) => {
+  vm.set('greet', (atNamed: any = {}) => {
     const name = atNamed.name || 'Unknown'
     const greeting = atNamed.greeting || 'Hello'
     const extra = atNamed.extra || ''
@@ -548,7 +548,7 @@ test('@named pattern - atNamed parameters with varadic args', async () => {
   `)
 
   const vm = new VM(bytecode)
-  vm.registerFunction('cmd', (atNamed: any = {}, ...rest: string[]) => {
+  vm.set('cmd', (atNamed: any = {}, ...rest: string[]) => {
     return { rest, namedArg: atNamed['named'] }
   })
 
@@ -573,7 +573,7 @@ test("@named pattern - mixed positional and atOptions", async () => {
   `)
 
   const vm = new VM(bytecode)
-  vm.registerFunction('configure', (name: string, atOptions: any = {}) => {
+  vm.set('configure', (name: string, atOptions: any = {}) => {
     return {
       name,
       debug: atOptions.debug || false,
@@ -600,7 +600,7 @@ test("@named pattern - with default empty object", async () => {
   `)
 
   const vm = new VM(bytecode)
-  vm.registerFunction('build', (name: string, atConfig: any = {}) => {
+  vm.set('build', (name: string, atConfig: any = {}) => {
     return `Building ${name} with ${Object.keys(atConfig).length} options`
   })
 
@@ -625,7 +625,7 @@ test("@named pattern - collects only unmatched named args", async () => {
   `)
 
   const vm = new VM(bytecode)
-  vm.registerFunction('process', (file: string, mode: string, atOptions: any = {}) => {
+  vm.set('process', (file: string, mode: string, atOptions: any = {}) => {
     // file and mode are matched, extra1 and extra2 go to atOptions
     return {
       file,
@@ -675,7 +675,7 @@ test("Native function receives Reef function as callback - basic map", async ()
   const vm = new VM(bytecode)
 
   // Native function that takes an array and a callback
-  vm.registerFunction('map', async (array: any[], callback: Function) => {
+  vm.set('map', async (array: any[], callback: Function) => {
     const results = []
     for (const item of array) {
       results.push(await callback(item))
@@ -732,7 +732,7 @@ test("Native function receives Reef function - iterator pattern with each", asyn
   const vm = new VM(bytecode)
 
   // Native 'each' function (like Ruby's each)
-  vm.registerFunction('each', async (array: any[], callback: Function) => {
+  vm.set('each', async (array: any[], callback: Function) => {
     for (const item of array) {
       await callback(item)
     }
@@ -773,7 +773,7 @@ test("Native function receives Reef function - filter pattern", async () => {
   const vm = new VM(bytecode)
 
   // Native filter function
-  vm.registerFunction('filter', async (array: any[], predicate: Function) => {
+  vm.set('filter', async (array: any[], predicate: Function) => {
     const results = []
     for (const item of array) {
       if (await predicate(item)) {
@@ -824,7 +824,7 @@ test("Native function receives Reef function - closure capturing", async () => {
 
   const vm = new VM(bytecode)
 
-  vm.registerFunction('map', async (array: any[], callback: Function) => {
+  vm.set('map', async (array: any[], callback: Function) => {
     const results = []
     for (const item of array) {
       results.push(await callback(item))
@@ -873,7 +873,7 @@ test("Native function receives Reef function - multiple arguments", async () =>
   const vm = new VM(bytecode)
 
   // Native reduce function (accumulator, array, callback)
-  vm.registerFunction('reduce', async (array: any[], initial: any, callback: Function) => {
+  vm.set('reduce', async (array: any[], initial: any, callback: Function) => {
     let acc = initial
     for (const item of array) {
       acc = await callback(acc, item)
@@ -913,7 +913,7 @@ test("Native function receives Reef function - returns non-primitive", async ()
 
   const vm = new VM(bytecode)
 
-  vm.registerFunction('map', async (array: any[], callback: Function) => {
+  vm.set('map', async (array: any[], callback: Function) => {
     const results = []
     for (const item of array) {
       results.push(await callback(item))
@@ -965,7 +965,7 @@ test("Native function calls Reef function - basic", async () => {
 
   const vm = new VM(bytecode)
 
-  vm.registerFunction('process', async function (n: number) {
+  vm.setFunction('process', async function (n: number) {
     return await this.call('double', n)
   })
 
@@ -1006,7 +1006,7 @@ test("Native function calls multiple Reef functions", async () => {
 
   const vm = new VM(bytecode)
 
-  vm.registerFunction('orchestrate', async function (n: number) {
+  vm.setFunction('orchestrate', async function (n: number) {
     const doubled = await this.call('double', n)
     const tripled = await this.call('triple', n)
 
@@ -1064,7 +1064,7 @@ test("Native function conditionally calls Reef functions", async () => {
 
   const vm = new VM(bytecode)
 
-  vm.registerFunction('validate', async function (n: number) {
+  vm.setFunction('validate', async function (n: number) {
     const isPositive = await this.call('is_positive', n)
 
     if (isPositive) {
@@ -1105,7 +1105,7 @@ test("Native function calls Reef function with closure", async () => {
 
   const vm = new VM(bytecode)
 
-  vm.registerFunction('transform', async function (n: number) {
+  vm.setFunction('transform', async function (n: number) {
     return await this.call('multiply_by_ten', n)
   })
 
@@ -1143,7 +1143,7 @@ test("Native function uses Reef function as filter predicate", async () => {
 
   const vm = new VM(bytecode)
 
-  vm.registerFunction('filter_evens', async function (array: any[]) {
+  vm.setFunction('filter_evens', async function (array: any[]) {
     const results = []
     for (const item of array) {
       if (await this.call('is_even', item)) {
@@ -1199,7 +1199,7 @@ test("Reef calls native calls Reef - roundtrip", async () => {
 
   const vm = new VM(bytecode)
 
-  vm.registerFunction('native_helper', async function (n: number) {
+  vm.setFunction('native_helper', async function (n: number) {
     const squared = await this.call('square', n)
     return squared + 1  // Add 1 to the squared result
   })
@@ -1232,7 +1232,7 @@ test("Native function calls Reef function with multiple arguments", async () =>
 
   const vm = new VM(bytecode)
 
-  vm.registerFunction('calculate', async function () {
+  vm.setFunction('calculate', async function () {
     return await this.call('add_three', 10, 20, 30)
   })
 
@@ -1266,7 +1266,7 @@ test("Native function calls Reef function that returns complex type", async () =
 
   const vm = new VM(bytecode)
 
-  vm.registerFunction('create_user', async function () {
+  vm.setFunction('create_user', async function () {
     return await this.call('make_user', "Alice", 30)
   })
 
@@ -1289,7 +1289,7 @@ test("Native function calls non-existent Reef function - throws error", async ()
 
   const vm = new VM(bytecode)
 
-  vm.registerFunction('bad_caller', async function () {
+  vm.setFunction('bad_caller', async function () {
     return await this.call('nonexistent', 42)
   })
 
@@ -1299,7 +1299,7 @@ test("Native function calls non-existent Reef function - throws error", async ()
 test("Native function calls Reef function with named arguments", async () => {
   const bytecode = toBytecode(`
     ; Reef function with default parameters
-    MAKE_FUNCTION (name greeting='Hello') .greet_body 
+    MAKE_FUNCTION (name greeting='Hello') .greet_body
     STORE greet
     JUMP .skip_greet
     .greet_body:
@@ -1387,7 +1387,7 @@ test("Native function receives Reef closure with default params - calls with nam
   const vm = new VM(bytecode)
 
   // Native function that calls the Reef closure with named arguments
-  vm.registerFunction('map', async (array: any[], callback: Function) => {
+  vm.set('map', async (array: any[], callback: Function) => {
     const results = []
     for (const item of array) {
       // Call with named argument to override the default
@@ -1457,7 +1457,7 @@ test("Native function receives Reef closure with variadic parameters", async ()
   const vm = new VM(bytecode)
 
   // Native function that calls the variadic Reef closure with multiple args
-  vm.registerFunction('process', async (callback: Function) => {
+  vm.set('process', async (callback: Function) => {
     // Call with varying number of arguments
     const result1 = await callback(1, 2, 3)
     const result2 = await callback(10, 20)
@@ -1508,7 +1508,7 @@ test("Native function receives Reef closure with @named parameter", async () =>
   const vm = new VM(bytecode)
 
   // Native function that calls Reef closure with named arguments
-  vm.registerFunction('format_messages', async (messages: any[], formatter: Function) => {
+  vm.set('format_messages', async (messages: any[], formatter: Function) => {
     const results = []
     for (const msg of messages) {
       // Call with named arguments
@@ -1553,7 +1553,7 @@ test("Native function receives Reef closure - calls with only named arguments",
   const vm = new VM(bytecode)
 
   // Native function that calls Reef closure with ONLY named arguments
-  vm.registerFunction('compute', async (callback: Function) => {
+  vm.set('compute', async (callback: Function) => {
     // First call with all named args
     const result1 = await callback({ x: 10, y: 20, z: 30 })
 
@@ -1619,7 +1619,7 @@ test("Native function receives Reef closure with mixed positional and variadic",
   const vm = new VM(bytecode)
 
   // Native function that calls Reef closure with mixed args
-  vm.registerFunction('process_numbers', async (calculator: Function) => {
+  vm.set('process_numbers', async (calculator: Function) => {
     // Call with fixed multiplier and variadic numbers
     const result1 = await calculator(10, 1, 2, 3)  // 10 * (1+2+3) = 60
     const result2 = await calculator(5, 4, 6)      // 5 * (4+6) = 50
diff --git a/tests/regex.test.ts b/tests/regex.test.ts
index 72927d0..2e2caa2 100644
--- a/tests/regex.test.ts
+++ b/tests/regex.test.ts
@@ -399,7 +399,7 @@ describe("RegExp", () => {
     const vm = new VM(bytecode)
 
     // Register a native function that takes a string and regex
-    vm.registerFunction('match', (str: string, pattern: RegExp) => {
+    vm.set('match', (str: string, pattern: RegExp) => {
       return pattern.test(str)
     })
 
@@ -422,7 +422,7 @@ describe("RegExp", () => {
 
     const vm = new VM(bytecode)
 
-    vm.registerFunction('replace', (str: string, pattern: RegExp, replacement: string) => {
+    vm.set('replace', (str: string, pattern: RegExp, replacement: string) => {
       return str.replace(pattern, replacement)
     })
 
@@ -444,7 +444,7 @@ describe("RegExp", () => {
 
     const vm = new VM(bytecode)
 
-    vm.registerFunction('extractNumbers', (str: string, pattern: RegExp) => {
+    vm.set('extractNumbers', (str: string, pattern: RegExp) => {
       return str.match(pattern) || []
     })