usethis-python · nathanjmcdougall · Mar 30, 2026 · Mar 27, 2026 · Mar 27, 2026 · Mar 27, 2026
diff --git a/AGENTS.md b/AGENTS.md
@@ -60,6 +60,7 @@ usethis                           # usethis: Automate Python project setup and d
 │   │   ├── errors                # Error types for INI file operations.
 │   │   └── io_                   # INI file I/O manager.
 │   ├── pyproject_toml            # pyproject.toml file reading and writing.
+│   │   ├── deps                  # Dependency extraction from pyproject.toml.
 │   │   ├── errors                # Error types for pyproject.toml operations.
 │   │   ├── io_                   # pyproject.toml file I/O manager.
 │   │   ├── name                  # Project name and description extraction from pyproject.toml.

diff --git a/docs/module-tree.txt b/docs/module-tree.txt
@@ -49,6 +49,7 @@ usethis                           # usethis: Automate Python project setup and d
 │   │   ├── errors                # Error types for INI file operations.
 │   │   └── io_                   # INI file I/O manager.
 │   ├── pyproject_toml            # pyproject.toml file reading and writing.
+│   │   ├── deps                  # Dependency extraction from pyproject.toml.
 │   │   ├── errors                # Error types for pyproject.toml operations.
 │   │   ├── io_                   # pyproject.toml file I/O manager.
 │   │   ├── name                  # Project name and description extraction from pyproject.toml.

diff --git a/src/usethis/_backend/uv/available.py b/src/usethis/_backend/uv/available.py
@@ -1,14 +1,37 @@
 """Check whether the uv CLI is available."""
 
+from packaging.requirements import InvalidRequirement
+
 from usethis._backend.uv.call import call_uv_subprocess
 from usethis._backend.uv.errors import UVSubprocessFailedError
+from usethis._file.pyproject_toml.deps import get_dep_groups, get_project_deps
+from usethis._file.pyproject_toml.errors import PyprojectTOMLError
+from usethis._types.deps import Dependency
 
 
 def is_uv_available() -> bool:
     """Check if the `uv` command is available in the current environment."""
     try:
         call_uv_subprocess(["--version"], change_toml=False)
     except UVSubprocessFailedError:
-        return False
+        return _is_uv_a_dep()
 
     return True
+
+
+def _is_uv_a_dep() -> bool:
+    """Check if uv is declared as a project dependency or in a dependency group."""
+    uv_dep = Dependency(name="uv")
+
+    try:
+        project_deps = get_project_deps()
+    except (PyprojectTOMLError, InvalidRequirement):
+        project_deps = []
+
+    try:
+        dep_groups = get_dep_groups()
+    except (PyprojectTOMLError, InvalidRequirement):
+        dep_groups = {}
+
+    all_group_deps = [dep for group in dep_groups.values() for dep in group]
+    return any(dep.name == uv_dep.name for dep in project_deps + all_group_deps)
diff --git a/src/usethis/_deps.py b/src/usethis/_deps.py
@@ -2,11 +2,8 @@
 
 from __future__ import annotations
 
-from typing import Literal
+from typing import TYPE_CHECKING, Literal
 
-import pydantic
-from packaging.requirements import Requirement
-from pydantic import TypeAdapter
 from typing_extensions import assert_never
 
 from usethis._backend.dispatch import get_backend
@@ -19,11 +16,20 @@
 from usethis._backend.uv.errors import UVDepGroupError
 from usethis._config import usethis_config
 from usethis._console import instruct_print, tick_print
+from usethis._file.pyproject_toml.deps import (
+    get_dep_groups as _get_dep_groups,
+)
+from usethis._file.pyproject_toml.deps import (
+    get_project_deps as _get_project_deps,
+)
+from usethis._file.pyproject_toml.errors import PyprojectTOMLDepsError
 from usethis._file.pyproject_toml.io_ import PyprojectTOMLManager
 from usethis._types.backend import BackendEnum
-from usethis._types.deps import Dependency
 from usethis.errors import DepGroupError
 
+if TYPE_CHECKING:
+    from usethis._types.deps import Dependency
+
 
 def get_project_deps() -> list[Dependency]:
     """Get all project dependencies.
@@ -35,71 +41,16 @@ def get_project_deps() -> list[Dependency]:
     of the `pyproject.toml` file.
     """
     try:
-        pyproject = PyprojectTOMLManager().get()
-    except FileNotFoundError:
-        return []
-
-    try:
-        project_section = pyproject["project"]
-    except KeyError:
-        return []
-
-    if not isinstance(project_section, dict):
-        return []
-
-    try:
-        dep_section = project_section["dependencies"]
-    except KeyError:
-        return []
-
-    try:
-        req_strs = TypeAdapter(list[str]).validate_python(dep_section)
-    except pydantic.ValidationError as err:
-        msg = (
-            "Failed to parse the 'project.dependencies' section in 'pyproject.toml':\n"
-            f"{err}\n\n"
-            "Please check the section and try again."
-        )
-        raise UVDepGroupError(msg) from None
-
-    reqs = [Requirement(req_str) for req_str in req_strs]
-    deps = [Dependency(name=req.name, extras=frozenset(req.extras)) for req in reqs]
-    return deps
+        return _get_project_deps()
+    except PyprojectTOMLDepsError as err:
+        raise UVDepGroupError(str(err)) from None
 
 
 def get_dep_groups() -> dict[str, list[Dependency]]:
     try:
-        pyproject = PyprojectTOMLManager().get()
-    except FileNotFoundError:
-        return {}
-
-    try:
-        dep_groups_section = pyproject["dependency-groups"]
-    except KeyError:
-        # In the past might have been in [tool.uv.dev-dependencies] section when using
-        # uv but this will be deprecated, so we don't support it in usethis.
-        return {}
-
-    try:
-        req_strs_by_group = TypeAdapter(dict[str, list[str]]).validate_python(
-            dep_groups_section
-        )
-    except pydantic.ValidationError as err:
-        msg = (
-            "Failed to parse the 'dependency-groups' section in 'pyproject.toml':\n"
-            f"{err}\n\n"
-            "Please check the section and try again."
-        )
-        raise DepGroupError(msg) from None
-    reqs_by_group = {
-        group: [Requirement(req_str) for req_str in req_strs]
-        for group, req_strs in req_strs_by_group.items()
-    }
-    deps_by_group = {
-        group: [Dependency(name=req.name, extras=frozenset(req.extras)) for req in reqs]
-        for group, reqs in reqs_by_group.items()
-    }
-    return deps_by_group
+        return _get_dep_groups()
+    except PyprojectTOMLDepsError as err:
+        raise DepGroupError(str(err)) from None
 
 
 def get_deps_from_group(group: str) -> list[Dependency]:

diff --git a/src/usethis/_file/pyproject_toml/deps.py b/src/usethis/_file/pyproject_toml/deps.py
@@ -0,0 +1,83 @@
+"""Dependency extraction from pyproject.toml."""
+
+from __future__ import annotations
+
+import pydantic
+from packaging.requirements import Requirement
+from pydantic import TypeAdapter
+
+from usethis._file.pyproject_toml.errors import PyprojectTOMLDepsError
+from usethis._file.pyproject_toml.io_ import PyprojectTOMLManager
+from usethis._types.deps import Dependency
+
+
+def get_project_deps() -> list[Dependency]:
+    """Get all project dependencies from [project.dependencies].
+
+    This does not include development dependencies, e.g. not those in the
+    dependency-groups section, not extras/optional dependencies, not build dependencies.
+    """
+    try:
+        pyproject = PyprojectTOMLManager().get()
+    except FileNotFoundError:
+        return []
+
+    try:
+        project_section = pyproject["project"]
+    except KeyError:
+        return []
+
+    if not isinstance(project_section, dict):
+        return []
+
+    try:
+        dep_section = project_section["dependencies"]
+    except KeyError:
+        return []
+
+    try:
+        req_strs = TypeAdapter(list[str]).validate_python(dep_section)
+    except pydantic.ValidationError as err:
+        msg = (
+            "Failed to parse the 'project.dependencies' section in 'pyproject.toml':\n"
+            f"{err}\n\n"
+            "Please check the section and try again."
+        )
+        raise PyprojectTOMLDepsError(msg) from None
+
+    reqs = [Requirement(req_str) for req_str in req_strs]
+    return [Dependency(name=req.name, extras=frozenset(req.extras)) for req in reqs]
+
+
+def get_dep_groups() -> dict[str, list[Dependency]]:
+    """Get all dependency groups from [dependency-groups]."""
+    try:
+        pyproject = PyprojectTOMLManager().get()
+    except FileNotFoundError:
+        return {}
+
+    try:
+        dep_groups_section = pyproject["dependency-groups"]
+    except KeyError:
+        return {}
+
+    try:
+        req_strs_by_group = TypeAdapter(dict[str, list[str]]).validate_python(
+            dep_groups_section
+        )
+    except pydantic.ValidationError as err:
+        msg = (
+            "Failed to parse the 'dependency-groups' section in 'pyproject.toml':\n"
+            f"{err}\n\n"
+            "Please check the section and try again."
+        )
+        raise PyprojectTOMLDepsError(msg) from None
+
+    reqs_by_group = {
+        group: [Requirement(req_str) for req_str in req_strs]
+        for group, req_strs in req_strs_by_group.items()
+    }
+    return {
+        group: [Dependency(name=req.name, extras=frozenset(req.extras)) for req in reqs]
+        for group, reqs in reqs_by_group.items()
+    }
diff --git a/src/usethis/_file/pyproject_toml/errors.py b/src/usethis/_file/pyproject_toml/errors.py
@@ -70,3 +70,7 @@ class PyprojectTOMLValueAlreadySetError(PyprojectTOMLError, TOMLValueAlreadySetE
 
 class PyprojectTOMLValueMissingError(PyprojectTOMLError, TOMLValueMissingError):
     """Raised when a value is unexpectedly missing from the 'pyproject.toml' file."""
+
+
+class PyprojectTOMLDepsError(PyprojectTOMLError):
+    """Raised when dependency sections in 'pyproject.toml' cannot be parsed."""