diff --git a/noxfile.py b/noxfile.py
index 16b9bc64..0807e721 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -121,7 +121,7 @@ def test(session):
         "mypy   ~= 1.15.0",
         "pylint == 3.3.7",
     )
-    session.run("mypy", *map(str, src_dirs), str(compiled_dir))
+    session.run("mypy", *map(str, src_dirs))
     session.run("pylint", *map(str, src_dirs), env={"PYTHONPATH": str(compiled_dir)})
 
     # Publish coverage statistics. This also has to be run from the test session to access the coverage files.
diff --git a/pycyphal/application/register/_value.py b/pycyphal/application/register/_value.py
index 36dbf4dc..d5f75e5f 100644
--- a/pycyphal/application/register/_value.py
+++ b/pycyphal/application/register/_value.py
@@ -350,9 +350,21 @@ def _strictify(s: RelaxedValue) -> Value:
     if all(isinstance(x, bool) for x in s):
         return _strictify(Bit(s))
     if all(isinstance(x, (int, bool)) for x in s):
-        return _strictify(Natural64(s)) if all(x >= 0 for x in s) else _strictify(Integer64(s))
-    if all(isinstance(x, (float, int, bool)) for x in s):
-        return _strictify(Real64(s))
+        if len(s) <= 32:
+            return _strictify(Natural64(s)) if all(x >= 0 for x in s) else _strictify(Integer64(s))
+        elif len(s) <= 64:
+            return _strictify(Natural32(s)) if all(x >= 0 for x in s) else _strictify(Integer32(s))
+        elif len(s) <= 128:
+            return _strictify(Natural16(s)) if all(x >= 0 for x in s) else _strictify(Integer16(s))
+        elif len(s) <= 256:
+            return _strictify(Natural8(s)) if all(x >= 0 for x in s) else _strictify(Integer8(s))
+    elif all(isinstance(x, (float, int, bool)) for x in s):
+        if len(s) <= 32:
+            return _strictify(Real64(s))
+        elif len(s) <= 64:
+            return _strictify(Real32(s))
+        elif len(s) <= 128:
+            return _strictify(Real16(s))
 
     raise ValueConversionError(f"Don't know how to convert {s!r} into {Value}")  # pragma: no cover
 
diff --git a/pycyphal/dsdl/_compiler.py b/pycyphal/dsdl/_compiler.py
index c2279b8a..1bc199c8 100644
--- a/pycyphal/dsdl/_compiler.py
+++ b/pycyphal/dsdl/_compiler.py
@@ -15,7 +15,7 @@
 import nunavut
 import nunavut.lang
 import nunavut.jinja
-
+from pycyphal.dsdl._lockfile import Locker
 
 _AnyPath = Union[str, pathlib.Path]
 
@@ -171,14 +171,27 @@ def compile(  # pylint: disable=redefined-builtin
         (root_namespace_name,) = set(map(lambda x: x.root_namespace, composite_types))  # type: ignore
         _logger.info("Read %d definitions from root namespace %r", len(composite_types), root_namespace_name)
 
-        # Generate code
-        assert isinstance(output_directory, pathlib.Path)
         root_ns = nunavut.build_namespace_tree(
             types=composite_types,
             root_namespace_dir=str(root_namespace_directory),
             output_dir=str(output_directory),
             language_context=language_context,
         )
+    else:
+        root_ns = nunavut.build_namespace_tree(
+            types=[],
+            root_namespace_dir=str(""),
+            output_dir=str(output_directory),
+            language_context=language_context,
+        )
+
+    lockfile = Locker(
+        root_namespace_name=root_namespace_name if root_namespace_name else "_support_",
+        output_directory=output_directory,
+    )
+    if lockfile.create():
+        # Generate code
+        assert isinstance(output_directory, pathlib.Path)
         code_generator = nunavut.jinja.DSDLCodeGenerator(
             namespace=root_ns,
             generate_namespace_types=nunavut.YesNoDefault.YES,
@@ -191,36 +204,31 @@ def compile(  # pylint: disable=redefined-builtin
             root_namespace_name,
             time.monotonic() - started_at,
         )
-    else:
-        root_ns = nunavut.build_namespace_tree(
-            types=[],
-            root_namespace_dir=str(""),
-            output_dir=str(output_directory),
-            language_context=language_context,
-        )
 
-    support_generator = nunavut.jinja.SupportGenerator(
-        namespace=root_ns,
-    )
-    support_generator.generate_all()
+        support_generator = nunavut.jinja.SupportGenerator(
+            namespace=root_ns,
+        )
+        support_generator.generate_all()
 
-    # A minor UX improvement; see https://github.com/OpenCyphal/pycyphal/issues/115
-    for p in sys.path:
-        if pathlib.Path(p).resolve() == pathlib.Path(output_directory):
-            break
-    else:
-        if os.name == "nt":
-            quick_fix = f'Quick fix: `$env:PYTHONPATH += ";{output_directory.resolve()}"`'
-        elif os.name == "posix":
-            quick_fix = f'Quick fix: `export PYTHONPATH="{output_directory.resolve()}"`'
+        # A minor UX improvement; see https://github.com/OpenCyphal/pycyphal/issues/115
+        for p in sys.path:
+            if pathlib.Path(p).resolve() == pathlib.Path(output_directory):
+                break
         else:
-            quick_fix = "Quick fix is not available for this OS."
-        _logger.info(
-            "Generated package is stored in %r, which is not in Python module search path list. "
-            "The package will fail to import unless you add the destination directory to sys.path or PYTHONPATH. %s",
-            str(output_directory),
-            quick_fix,
-        )
+            if os.name == "nt":
+                quick_fix = f'Quick fix: `$env:PYTHONPATH += ";{output_directory.resolve()}"`'
+            elif os.name == "posix":
+                quick_fix = f'Quick fix: `export PYTHONPATH="{output_directory.resolve()}"`'
+            else:
+                quick_fix = "Quick fix is not available for this OS."
+            _logger.info(
+                "Generated package is stored in %r, which is not in Python module search path list. "
+                "The package will fail to import unless you add the destination directory to sys.path or PYTHONPATH. %s",
+                str(output_directory),
+                quick_fix,
+            )
+
+        lockfile.remove()
 
     return GeneratedPackageInfo(
         path=pathlib.Path(output_directory) / pathlib.Path(root_namespace_name),
diff --git a/pycyphal/dsdl/_lockfile.py b/pycyphal/dsdl/_lockfile.py
new file mode 100644
index 00000000..38cc3fc7
--- /dev/null
+++ b/pycyphal/dsdl/_lockfile.py
@@ -0,0 +1,49 @@
+import logging
+import pathlib
+import time
+from io import TextIOWrapper
+from pathlib import Path
+
+_logger = logging.getLogger(__name__)
+
+
+class Locker:
+
+    def __init__(self, output_directory: pathlib.Path, root_namespace_name: str) -> None:
+        self._output_directory = output_directory
+        self._root_namespace_name = root_namespace_name
+        self._lockfile: TextIOWrapper | None = None
+
+    @property
+    def _lockfile_path(self) -> Path:
+        return self._output_directory / f"{self._root_namespace_name}.lock"
+
+    def create(self) -> bool:
+        """
+        True means compilation needs to proceed.
+        False means another process already compiled the namespace so we just waited for the lockfile to disappear before returning.
+        """
+        # TODO Read about context manager
+        try:
+            pathlib.Path(self._output_directory).mkdir(parents=True, exist_ok=True)
+            self._lockfile = open(self._lockfile_path, "x")
+            _logger.debug("Created lockfile %s", self._lockfile_path)
+            return True
+        except FileExistsError:
+            pass
+        while pathlib.Path(self._lockfile_path).exists():
+            _logger.debug("Waiting for lockfile %s", self._lockfile_path)
+            time.sleep(1)
+
+        _logger.debug("Done waiting %s", self._lockfile_path)
+
+        return False
+
+    def remove(self) -> None:
+        """
+        Invoking remove before creating lockfile is not allowed.
+        """
+        assert self._lockfile is not None
+        self._lockfile.close()
+        pathlib.Path(self._lockfile_path).unlink()
+        _logger.debug("Removed lockfile %s", self._lockfile_path)
diff --git a/setup.cfg b/setup.cfg
index d2c7792d..3d7c22a6 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -149,6 +149,10 @@ ignore_missing_imports = True
 ignore_errors = True
 ignore_missing_imports = True
 
+[mypy-test_dsdl_namespace.*]
+ignore_errors = True
+ignore_missing_imports = True
+
 [mypy-numpy]
 ignore_errors = True
 ignore_missing_imports = True
diff --git a/tests/dsdl/_compiler.py b/tests/dsdl/_compiler.py
index 26eff3e5..ecc53ec2 100644
--- a/tests/dsdl/_compiler.py
+++ b/tests/dsdl/_compiler.py
@@ -2,7 +2,10 @@
 # This software is distributed under the terms of the MIT License.
 # Author: Pavel Kirienko <pavel@opencyphal.org>
 
+import random
 import sys
+import threading
+import time
 import typing
 import logging
 import pathlib
@@ -10,7 +13,7 @@
 import pytest
 import pycyphal.dsdl
 from pycyphal.dsdl import remove_import_hooks, add_import_hook
-
+from pycyphal.dsdl._lockfile import Locker
 from .conftest import DEMO_DIR
 
 
@@ -64,3 +67,28 @@ def _unittest_remove_import_hooks() -> None:
 def _unittest_issue_133() -> None:
     with pytest.raises(ValueError, match=".*output directory.*"):
         pycyphal.dsdl.compile(pathlib.Path.cwd() / "irrelevant")
+
+
+def _unittest_lockfile_cant_be_recreated() -> None:
+    output_directory = pathlib.Path(tempfile.gettempdir())
+    root_namespace_name = str(random.getrandbits(64))
+
+    lockfile1 = Locker(output_directory, root_namespace_name)
+    lockfile2 = Locker(output_directory, root_namespace_name)
+
+    assert lockfile1.create() is True
+
+    def remove_lockfile1() -> None:
+        time.sleep(5)
+        lockfile1.remove()
+
+    threading.Thread(target=remove_lockfile1).start()
+    assert lockfile2.create() is False
+
+
+def _unittest_lockfile_is_removed() -> None:
+    output_directory = pathlib.Path(tempfile.gettempdir())
+
+    pycyphal.dsdl.compile(DEMO_DIR / "public_regulated_data_types" / "uavcan", output_directory=output_directory.name)
+
+    assert pathlib.Path.exists(output_directory / "uavcan.lock") is False