Built-in Functions

Core Functions

These functions are always available without any import:

// No import needed - available everywhere
print("Hello, World!")
let apiKey = env("ANTHROPIC_API_KEY")

print

Print to console:

print("Hello, World!")
print(someVariable)
print({ key: "value" })

Parameter	Type	Description
message	any	Value to print

env

Get environment variable:

let apiKey = env("ANTHROPIC_API_KEY")
let port = env("PORT", "3000")  // With default value

Parameter	Type	Description
name	text	Environment variable name
defaultValue	text?	Default if not set
Returns	text	Variable value

args

Access CLI arguments passed after the .vibe filename:

let all = args()            // All args as text[]
let first = args(0)         // Arg at index (or null)
let name = args("name")    // Value of --name flag (or null)

Parameter	Type	Description
(none)		Returns all args as array
index	number	Returns arg at index (or null)
name	text	Returns value of --name flag (or null)
Returns	text[] / text / null	Depends on argument

Named flags return "" (empty string) for boolean-style flags like --dry-run. Returns null when the flag is not present.

hasArg

Check if a CLI flag is present:

if hasArg("verbose") {
  print("Verbose mode enabled")
}

Parameter	Type	Description
name	text	Flag name without dashes
Returns	boolean	Whether flag is present

---

Utility Functions

Import from "system/utils":

import { uuid, now, random, jsonParse, jsonStringify } from "system/utils"

uuid

Generate UUID v4:

let id = uuid()  // "550e8400-e29b-41d4-a716-446655440000"

| Returns | text | UUID string |

now

Current timestamp in milliseconds:

let timestamp = now()  // 1705123456789

| Returns | number | Unix timestamp (ms) |

random

Generate random number:

let r = random()        // 0.0 to 1.0
let n = random(1, 10)   // 1 to 10 (integer)

Parameter	Type	Description
min	number?	Minimum (inclusive)
max	number?	Maximum (inclusive)
Returns	number	Random number

jsonParse

Parse JSON string:

let data = jsonParse('{"name": "Alice"}')

Parameter	Type	Description
text	text	JSON string
Returns	json	Parsed object

jsonStringify

Convert to JSON string:

let str = jsonStringify({ name: "Alice" })
let pretty = jsonStringify({ name: "Alice" }, true)

Parameter	Type	Description
value	json	Value to stringify
pretty	boolean?	Pretty print (default: false)
Returns	text	JSON string

---

System Tools

Import from "system/tools" for AI tool use:

import { readFile, writeFile, bash } from "system/tools"

model agent = {
  tools: [readFile, writeFile, bash]
}

readFile

Read file contents:

let content = readFile("data.txt")
let lines = readFile("data.txt", 1, 10)  // Lines 1-10

Parameter	Type	Description
path	text	File path
startLine	number?	Starting line (1-indexed)
endLine	number?	Ending line
Returns	text	File contents

writeFile

Write to file:

writeFile("output.txt", "Hello, World!")

Parameter	Type	Description
path	text	File path
content	text	Content to write
Returns	boolean	Success

appendFile

Append to file:

appendFile("log.txt", "New entry\n")

Parameter	Type	Description
path	text	File path
content	text	Content to append
Returns	boolean	Success

fileExists

Check if file exists:

if fileExists("config.json") {
  // ...
}

Parameter	Type	Description
path	text	File path
Returns	boolean	Exists

listDir

List directory contents:

let files = listDir("./src")

Parameter	Type	Description
path	text	Directory path
Returns	text[]	File/folder names

edit

Edit specific lines in file:

edit("file.txt", 5, 10, "new content")

Parameter	Type	Description
path	text	File path
startLine	number	Start line (1-indexed)
endLine	number	End line
newText	text	Replacement text
Returns	text	Updated content

glob

Find files by pattern:

let tsFiles = glob("**/*.ts")
let srcFiles = glob("*.js", "./src")

Parameter	Type	Description
pattern	text	Glob pattern
cwd	text?	Working directory
Returns	text[]	Matching paths

grep

Search file contents:

let matches = grep("TODO", "./src", true)

Parameter	Type	Description
pattern	text	Search pattern
path	text	File/directory
ignoreCase	boolean?	Case insensitive
Returns	json[]	Matches with line info

mkdir

Create directory:

mkdir("./output")
mkdir("./a/b/c", true)  // Recursive

Parameter	Type	Description
path	text	Directory path
recursive	boolean?	Create parents
Returns	boolean	Success

dirExists

Check if directory exists:

if dirExists("./output") {
  // ...
}

Parameter	Type	Description
path	text	Directory path
Returns	boolean	Exists

bash

Execute shell command:

let result = bash("npm run build")
let result = bash("ls -la", "./src")
let result = bash("slow-command", ".", 60000)

Parameter	Type	Description
command	text	Shell command
cwd	text?	Working directory
timeout	number?	Timeout (ms)
Returns	json	{ stdout, stderr, exitCode }

runCode

Run code snippet:

let result = runCode("python", "print('Hello')")
let result = runCode("javascript", "console.log(1+1)")

Parameter	Type	Description
language	text	Language name
code	text	Code to run
Returns	json	Execution result

---

Array Methods

push

Add element to array (mutates array, returns array for chaining):

let items: text[] = []
items.push("first")
items.push("second")

// Chaining
let arr = [].push(1).push(2).push(3)

Parameter	Type	Description
element	any	Element to add
Returns	array	The array (for chaining)

pop

Remove and return last element:

let items = [1, 2, 3]
let last = items.pop()  // 3
// items is now [1, 2]

| Returns | any | The removed element |

len

Get length of array or string:

let arr = [1, 2, 3, 4, 5]
let count = arr.len()  // 5

let str = "hello"
let length = str.len()  // 5

| Returns | number | Length |