diff --git a/python/.gitignore b/python/.gitignore
index 5621902..23c6e30 100644
--- a/python/.gitignore
+++ b/python/.gitignore
@@ -1,7 +1,3 @@
-# Build artifacts dirs.
-/*.egg-info/
-/build/
-
 # Python bytecode.
 __pycache__/
 
diff --git a/python/CHANGES.md b/python/CHANGES.md
index dad2572..0675738 100644
--- a/python/CHANGES.md
+++ b/python/CHANGES.md
@@ -1,5 +1,9 @@
 # insta-science
 
+## 0.4.4
+
+Use a 'User-Agent' header of `insta-science/<version>` when fetching URLs.
+
 ## 0.4.3
 
 Implement proper HTTP error handling and add retry support in for failed `science` fetches.
diff --git a/python/RELEASE.md b/python/RELEASE.md
index 3d55b36..c8233f7 100644
--- a/python/RELEASE.md
+++ b/python/RELEASE.md
@@ -4,7 +4,7 @@
 
 ### Version Bump and Changelog
 
-1. Bump the version in [`insta_science/version.py`](insta_science/version.py).
+1. Bump the version in [`insta_science/_internal/version.py`](insta_science/_internal/version.py).
 2. Run `uv run dev-cmd` as a sanity check on the state of the project.
 3. Update [`CHANGES.md`](CHANGES.md) with any changes that are likely to be useful to consumers.
 4. Run `uv run dev-cmd -q release -- --dry-run` as a sanity check the release will work once the
diff --git a/python/insta_science/__init__.py b/python/insta_science/__init__.py
index 97d5c32..89a336e 100644
--- a/python/insta_science/__init__.py
+++ b/python/insta_science/__init__.py
@@ -11,9 +11,9 @@
     ScienceExe,
     ScienceNotFound,
     Url,
+    __version__,
     ensure_installed,
 )
-from .version import __version__
 
 __all__ = (
     "CURRENT_PLATFORM",
diff --git a/python/insta_science/_internal/__init__.py b/python/insta_science/_internal/__init__.py
index 3ea836a..763e39b 100644
--- a/python/insta_science/_internal/__init__.py
+++ b/python/insta_science/_internal/__init__.py
@@ -6,6 +6,7 @@
 from .model import Digest, Science, ScienceExe, Url
 from .platform import CURRENT_PLATFORM, Platform
 from .science import ensure_installed
+from .version import __version__
 
 __all__ = (
     "CURRENT_PLATFORM",
@@ -17,5 +18,6 @@
     "ScienceExe",
     "ScienceNotFound",
     "Url",
+    "__version__",
     "ensure_installed",
 )
diff --git a/python/insta_science/_internal/fetcher.py b/python/insta_science/_internal/fetcher.py
index 321fdfa..9ad03b3 100644
--- a/python/insta_science/_internal/fetcher.py
+++ b/python/insta_science/_internal/fetcher.py
@@ -29,6 +29,7 @@
 from .errors import InputError
 from .hashing import Digest, ExpectedDigest, Fingerprint
 from .model import Url
+from .version import __version__
 
 logger = logging.getLogger(__name__)
 
@@ -95,6 +96,7 @@ def require_password(auth_type: str) -> str:
 
 def _configured_client(url: Url, headers: Mapping[str, str] | None = None) -> httpx.Client:
     headers = dict(headers) if headers else {}
+    headers.setdefault("User-Agent", f"insta-science/{__version__}")
     auth = _configure_auth(url) if "Authorization" not in headers else None
     return httpx.Client(follow_redirects=True, headers=headers, auth=auth)
 
diff --git a/python/insta_science/version.py b/python/insta_science/_internal/version.py
similarity index 83%
rename from python/insta_science/version.py
rename to python/insta_science/_internal/version.py
index 74f04b1..1e01519 100644
--- a/python/insta_science/version.py
+++ b/python/insta_science/_internal/version.py
@@ -1,4 +1,4 @@
 # Copyright 2024 Science project contributors.
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
-__version__ = "0.4.3"
+__version__ = "0.4.4"
diff --git a/python/insta_science/util.py b/python/insta_science/util.py
index 3a63662..453bc6b 100644
--- a/python/insta_science/util.py
+++ b/python/insta_science/util.py
@@ -16,14 +16,13 @@
 
 from packaging.version import Version
 
-from . import CURRENT_PLATFORM, InputError, Platform, Science
+from . import CURRENT_PLATFORM, InputError, Platform, Science, __version__
 from ._internal import a_scie, parser, project, science
 from ._internal.bytes import ByteAmount
 from ._internal.cache import DownloadCache, download_cache
 from ._internal.colors import Colors, color_support
 from ._internal.du import DiskUsage
 from ._internal.model import Configuration
-from .version import __version__
 
 
 def download(
diff --git a/python/pyproject.toml b/python/pyproject.toml
index 5bfa0c2..f172780 100644
--- a/python/pyproject.toml
+++ b/python/pyproject.toml
@@ -57,7 +57,7 @@ insta-science = "insta_science.shim:main"
 insta-science-util = "insta_science.util:main"
 
 [tool.setuptools.dynamic]
-version = {attr = "insta_science.version.__version__"}
+version = {attr = "insta_science._internal.version.__version__"}
 
 [tool.setuptools.packages.find]
 where = ["."]
@@ -71,6 +71,7 @@ dev = [
     "pytest",
     "pytest-xdist",
     "ruff",
+    "setuptools",
     "types-appdirs",
     "types-colorama",
     "types-tqdm",
diff --git a/python/setup.py b/python/setup.py
new file mode 100644
index 0000000..f47fbcc
--- /dev/null
+++ b/python/setup.py
@@ -0,0 +1,39 @@
+# Copyright 2025 Science project contributors.
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+import atexit
+import shutil
+import tempfile
+from pathlib import Path
+
+from setuptools import setup
+
+_BUILD_DIR: Path | None = None
+
+
+def ensure_unique_build_dir() -> Path:
+    global _BUILD_DIR
+    if _BUILD_DIR is None:
+        _build_dir = Path(tempfile.mkdtemp(prefix="insta-science-dist-build."))
+        atexit.register(shutil.rmtree, _build_dir, ignore_errors=True)
+        _BUILD_DIR = _build_dir
+    return _BUILD_DIR
+
+
+def unique_build_dir(name) -> str:
+    path = ensure_unique_build_dir() / name
+    path.mkdir()
+    return str(path)
+
+
+if __name__ == "__main__":
+    setup(
+        # The `egg_info --egg-base`, `build --build-base` and `bdist_wheel --bdist-dir` setup.py
+        # sub-command options we pass below work around the otherwise default `<CWD>/build/`
+        # directory for all three which defeats concurrency in tests.
+        options={
+            "egg_info": {"egg_base": unique_build_dir("egg_base")},
+            "build": {"build_base": unique_build_dir("build_base")},
+            "bdist_wheel": {"bdist_dir": unique_build_dir("bdist_dir")},
+        }
+    )
diff --git a/python/uv.lock b/python/uv.lock
index ef1a496..20b48c7 100644
--- a/python/uv.lock
+++ b/python/uv.lock
@@ -88,7 +88,7 @@ wheels = [
 
 [[package]]
 name = "dev-cmd"
-version = "0.10.4"
+version = "0.11.1"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "aioconsole" },
@@ -97,9 +97,9 @@ dependencies = [
     { name = "tomli", marker = "python_full_version < '3.11'" },
     { name = "typing-extensions" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/f9/0a/1b8fddadf62feae0ac705926cf3350d2998ee273966e594d28d955d8e95f/dev_cmd-0.10.4.tar.gz", hash = "sha256:4806e5c14b2da723b07c3e1e072b0113c0945ec1673469f0a6db6ff7228b73ba", size = 39987 }
+sdist = { url = "https://files.pythonhosted.org/packages/71/05/9fd907b1ad956cd8979faa2e5bd00c4866c03e97b42172702c8f29dc0bc4/dev_cmd-0.11.1.tar.gz", hash = "sha256:4a9d30bb399b7cb6e1948c882ad883d54a6e8b77cb65f0c377220ccf7927ace3", size = 41158 }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/f3/84/8252735984970a9b34decd7f339a88ba48b7b6910a1c57cffd2c6415d97f/dev_cmd-0.10.4-py3-none-any.whl", hash = "sha256:f30c33808767f8d172685e2a30c81eddca654d315e493d86a9f2cf7f78b83bae", size = 26881 },
+    { url = "https://files.pythonhosted.org/packages/70/0f/c4c66db5807a9a1527982eebd4ba62a2f76efcc6fb8b7e9d2c63bc3b4cc2/dev_cmd-0.11.1-py3-none-any.whl", hash = "sha256:395f0ac099e8ec40736b3865602c809082b84bb28c9bd062fd06ba35e7b9954e", size = 27068 },
 ]
 
 [[package]]
@@ -187,7 +187,7 @@ wheels = [
 
 [[package]]
 name = "insta-science"
-version = "0.4.3"
+version = "0.4.4"
 source = { editable = "." }
 dependencies = [
     { name = "ansicolors" },
@@ -210,6 +210,8 @@ dev = [
     { name = "pytest" },
     { name = "pytest-xdist" },
     { name = "ruff" },
+    { name = "setuptools", version = "75.3.0", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.9'" },
+    { name = "setuptools", version = "75.8.0", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.9'" },
     { name = "types-appdirs" },
     { name = "types-colorama" },
     { name = "types-tqdm" },
@@ -237,6 +239,7 @@ dev = [
     { name = "pytest" },
     { name = "pytest-xdist" },
     { name = "ruff" },
+    { name = "setuptools" },
     { name = "types-appdirs" },
     { name = "types-colorama" },
     { name = "types-tqdm" },
@@ -377,6 +380,30 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/13/9f/026e18ca7d7766783d779dae5e9c656746c6ede36ef73c6d934aaf4a6dec/ruff-0.8.4-py3-none-win_arm64.whl", hash = "sha256:9183dd615d8df50defa8b1d9a074053891ba39025cf5ae88e8bcb52edcc4bf08", size = 9074500 },
 ]
 
+[[package]]
+name = "setuptools"
+version = "75.3.0"
+source = { registry = "https://pypi.org/simple" }
+resolution-markers = [
+    "python_full_version < '3.9'",
+]
+sdist = { url = "https://files.pythonhosted.org/packages/ed/22/a438e0caa4576f8c383fa4d35f1cc01655a46c75be358960d815bfbb12bd/setuptools-75.3.0.tar.gz", hash = "sha256:fba5dd4d766e97be1b1681d98712680ae8f2f26d7881245f2ce9e40714f1a686", size = 1351577 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/90/12/282ee9bce8b58130cb762fbc9beabd531549952cac11fc56add11dcb7ea0/setuptools-75.3.0-py3-none-any.whl", hash = "sha256:f2504966861356aa38616760c0f66568e535562374995367b4e69c7143cf6bcd", size = 1251070 },
+]
+
+[[package]]
+name = "setuptools"
+version = "75.8.0"
+source = { registry = "https://pypi.org/simple" }
+resolution-markers = [
+    "python_full_version >= '3.9'",
+]
+sdist = { url = "https://files.pythonhosted.org/packages/92/ec/089608b791d210aec4e7f97488e67ab0d33add3efccb83a056cbafe3a2a6/setuptools-75.8.0.tar.gz", hash = "sha256:c5afc8f407c626b8313a86e10311dd3f661c6cd9c09d4bf8c15c0e11f9f2b0e6", size = 1343222 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/69/8a/b9dc7678803429e4a3bc9ba462fa3dd9066824d3c607490235c6a796be5a/setuptools-75.8.0-py3-none-any.whl", hash = "sha256:e3982f444617239225d675215d51f6ba05f845d4eec313da4418fdbb56fb27e3", size = 1228782 },
+]
+
 [[package]]
 name = "sniffio"
 version = "1.3.1"