import hashlib
import random
import string


def first_word(s: str) -> str:
    """Returns the first word from a string."""
    return s.split(' ', 1)[0]


def truncate_str(s: str, maxlen: int = 30) -> str:
    """Truncates a string to fit within a maximum length, adding '...' if truncated."""
    if len(s) <= maxlen:
        return s
    return s[: maxlen - 3] + '...'


def random_str(maxlen: int = 10) -> str:
    """Returns a random string of letters."""
    return ''.join(random.choice(string.ascii_letters) for _ in range(maxlen))


def md5_hash(s: str) -> str:
    """Computes the MD5 hash of a string."""
    return hashlib.md5(s.encode()).hexdigest()