Standard library modules

Monty ships a fixed set of built-in stdlib modules. import of anything else raises ModuleNotFoundError: there is no sys.path, no site-packages, and no way for sandboxed code to load additional modules.

Modules available

Module	See
asyncio	asyncio.md
base64	base64.md
binascii	base64.md
collections	collections.md
dataclasses	dataclasses.md
datetime	datetime.md
functools	functools.md
itertools	itertools.md
json	json.md
math	math.md
os	os.md
pathlib	pathlib.md
re	re.md
sys	sys.md
typing	typing.md
unicodedata	unicodedata.md

collections is importable and exposes deque, Counter, defaultdict, and namedtuple; OrderedDict, ChainMap, and the UserDict / UserList / UserString wrappers are missing (see collections.md).

A gc module exposing collect() / enable() / disable() is compiled in only under the test-hooks Cargo feature, for Monty’s own test suite; production sandboxes never see it.

Notable modules NOT available

Common modules that are not importable in Monty (non-exhaustive): abc, argparse, array, bisect, contextlib, copy, csv, ctypes, decimal, enum, fractions, hashlib, heapq, hmac, http, inspect, io, logging, multiprocessing, operator, pickle, queue, random, socket, string, struct, subprocess, tempfile, threading, time, traceback, unittest, urllib, uuid, warnings, weakref, zipfile, zlib.

socket, subprocess, multiprocessing, threading and ctypes are excluded because they would breach the sandbox. Others (enum, operator) are unimplemented and may appear over time.

Some available modules cover only part of their CPython surface: itertools implements eleven of its callables, functools only reduce and partial, collections only the four types above, and binascii everything except the uuencode and quoted-printable conversions. The absent names are missing from the module namespace rather than stubbed, so they fail type checking as well as raising AttributeError at runtime; see each module’s page for the specifics.

Modules the type checker resolves but the runtime does not

abc, types, typing_extensions, _collections_abc and _typeshed back the vendored stubs (e.g. @abstractmethod on protocol members), so they have to resolve during type checking. Importing them therefore type-checks clean but still raises ModuleNotFoundError at runtime.