diff --git a/skore-local-project/pyproject.toml b/skore-local-project/pyproject.toml
index 8b8b4f451..23a91124a 100644
--- a/skore-local-project/pyproject.toml
+++ b/skore-local-project/pyproject.toml
@@ -100,6 +100,7 @@ convention = "numpy"
 
 [tool.mypy]
 exclude = ["hatch/", "tests/"]
+strict = true
 
 [[tool.mypy.overrides]]
 follow_untyped_imports = true
diff --git a/skore-local-project/src/skore_local_project/metadata.py b/skore-local-project/src/skore_local_project/metadata.py
index 9d64dd758..1dfcf376d 100644
--- a/skore-local-project/src/skore_local_project/metadata.py
+++ b/skore-local-project/src/skore_local_project/metadata.py
@@ -12,7 +12,8 @@
 from joblib import hash
 
 if TYPE_CHECKING:
-    from typing import Any
+    from collections.abc import Generator
+    from typing import Any, Literal
 
     from skore import CrossValidationReport, EstimatorReport
 
@@ -20,13 +21,17 @@
 def cast_to_float(value: Any) -> float | None:
     """Cast value to float."""
     with suppress(TypeError):
-        if isfinite(value := float(value)):
-            return value
+        float_value = float(value)
+
+        if isfinite(float_value):
+            return float_value
 
     return None
 
 
-def report_type(report: EstimatorReport | CrossValidationReport):
+def report_type(
+    report: EstimatorReport | CrossValidationReport,
+) -> Literal["cross-validation", "estimator"]:
     """Human readable type of a report."""
     from skore import CrossValidationReport, EstimatorReport
 
@@ -76,12 +81,12 @@ class ReportMetadata(ABC):
     report_type: str = field(init=False)
     dataset: str = field(init=False)
 
-    def __iter__(self):
+    def __iter__(self) -> Generator[tuple[str, str], None, None]:
         """Iterate over the metadata."""
         for field in fields(self):  # noqa: F402
             yield (field.name, getattr(self, field.name))
 
-    def __post_init__(self, report: EstimatorReport | CrossValidationReport):
+    def __post_init__(self, report: EstimatorReport | CrossValidationReport) -> None:
         """Initialize dynamic fields."""
         self.date = datetime.now(timezone.utc).isoformat()
         self.learner = report.estimator_name_
@@ -106,7 +111,7 @@ def metric(report: EstimatorReport, name: str) -> float | None:
 
         return cast_to_float(getattr(report.metrics, name)(data_source="test"))
 
-    def __post_init__(self, report: EstimatorReport):  # type: ignore[override]
+    def __post_init__(self, report: EstimatorReport) -> None:  # type: ignore[override]
         """Initialize dynamic fields."""
         super().__post_init__(report)
 
@@ -152,7 +157,7 @@ def timing(report: CrossValidationReport, label: str) -> float | None:
 
         return cast_to_float(series.iloc[0])
 
-    def __post_init__(self, report: CrossValidationReport):  # type: ignore[override]
+    def __post_init__(self, report: CrossValidationReport) -> None:  # type: ignore[override]
         """Initialize dynamic fields."""
         super().__post_init__(report)
 
diff --git a/skore-local-project/src/skore_local_project/project.py b/skore-local-project/src/skore_local_project/project.py
index fdd726bfa..5aad0a719 100644
--- a/skore-local-project/src/skore_local_project/project.py
+++ b/skore-local-project/src/skore_local_project/project.py
@@ -6,7 +6,7 @@
 import os
 from functools import wraps
 from pathlib import Path
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, ParamSpec, Protocol, TypeVar, cast, runtime_checkable
 from uuid import uuid4
 
 import joblib
@@ -15,7 +15,12 @@
 from .metadata import CrossValidationReportMetadata, EstimatorReportMetadata
 from .storage import DiskCacheStorage
 
+P = ParamSpec("P")
+R = TypeVar("R")
+
+
 if TYPE_CHECKING:
+    from collections.abc import Callable
     from typing import TypedDict
 
     from skore import CrossValidationReport, EstimatorReport
@@ -40,17 +45,26 @@ class Metadata(TypedDict):  # noqa: D101
         predict_time_mean: float | None
 
 
-def ensure_project_is_not_deleted(method):
+def ensure_project_is_not_deleted(method: Callable[P, R]) -> Callable[P, R]:
     """Ensure project is not deleted, before executing any other operation."""
 
+    @runtime_checkable
+    class Project(Protocol):
+        name: str
+        _Project__projects_storage: DiskCacheStorage
+
     @wraps(method)
-    def wrapper(self, *args, **kwargs):
-        if self.name not in self._Project__projects_storage:
+    def wrapper(*args: P.args, **kwargs: P.kwargs) -> R:
+        project = args[0]
+
+        assert isinstance(project, Project), "You can only wrap `Project` methods"
+
+        if project.name not in project._Project__projects_storage:
             raise RuntimeError(
-                f"Skore could not proceed because {self!r} does not exist anymore."
+                f"Skore could not proceed because {project!r} does not exist anymore."
             )
 
-        return method(self, *args, **kwargs)
+        return method(*args, **kwargs)
 
     return wrapper
 
@@ -183,7 +197,7 @@ def pickle(report: EstimatorReport | CrossValidationReport) -> tuple[str, bytes]
         return pickle_hash, pickle_bytes
 
     @ensure_project_is_not_deleted
-    def put(self, key: str, report: EstimatorReport | CrossValidationReport):
+    def put(self, key: str, report: EstimatorReport | CrossValidationReport) -> None:
         """
         Put a key-report pair to the local project.
 
@@ -238,7 +252,9 @@ def get(self, id: str) -> EstimatorReport | CrossValidationReport:
         """Get a persisted report by its id."""
         if id in self.__artifacts_storage:
             with io.BytesIO(self.__artifacts_storage[id]) as stream:
-                return joblib.load(stream)
+                return cast(
+                    "EstimatorReport | CrossValidationReport", joblib.load(stream)
+                )
 
         raise KeyError(id)
 
@@ -275,7 +291,7 @@ def __repr__(self) -> str:  # noqa: D105
         )
 
     @staticmethod
-    def delete(name: str, *, workspace: Path | None = None):
+    def delete(name: str, *, workspace: Path | None = None) -> None:
         r"""
         Delete a local project.
 
diff --git a/skore-local-project/src/skore_local_project/storage.py b/skore-local-project/src/skore_local_project/storage.py
index f7b9df86a..4f2a5a2ec 100644
--- a/skore-local-project/src/skore_local_project/storage.py
+++ b/skore-local-project/src/skore_local_project/storage.py
@@ -106,7 +106,7 @@ def __getitem__(self, key: str) -> Any:
         with Cache(self.directory) as storage:
             return storage[key]
 
-    def __setitem__(self, key: str, value: Any):
+    def __setitem__(self, key: str, value: Any) -> None:
         """
         Set an item in the storage.
 
@@ -120,7 +120,7 @@ def __setitem__(self, key: str, value: Any):
         with Cache(self.directory) as storage:
             storage[key] = value
 
-    def __delitem__(self, key: str):
+    def __delitem__(self, key: str) -> None:
         """
         Delete an item from the storage.