fix: resolve file-artifact handles with uppercased uuid hex

The handle regex matches hex case-insensitively, but store keys are
lowercase uuid4 strings. Normalize the captured uuid to lowercase before
lookup so a handle echoed by the model with uppercase hex still resolves
to its bytes instead of leaking the raw token to the downstream tool.

lib/crewai/src/crewai/tools/file_artifact.py

@@ -187,7 +187,10 @@ def resolve_artifact_handles(value: Any) -> Any:
             return value
 
         def _sub(match: re.Match[str]) -> str:
-            artifact = _store.resolve(match.group(1))
+            # Store keys are lowercase uuid4 strings; the regex matches hex
+            # case-insensitively, so normalize before lookup in case the model
+            # echoed the handle with uppercase hex.
+            artifact = _store.resolve(match.group(1).lower())
             return artifact.as_base64() if artifact is not None else match.group(0)
 
         return _HANDLE_RE.sub(_sub, value)

lib/crewai/tests/tools/test_file_artifact.py

@@ -100,6 +100,16 @@ class TestResolveArtifactHandles:
         resolved = resolve_artifact_handles(handle)
         assert base64.b64decode(resolved) == data
 
+    def test_resolves_handle_with_uppercased_hex(self) -> None:
+        # A model may echo the handle with uppercase uuid hex; lookup must still
+        # hit the lowercase-keyed store.
+        data = b"upper-case-payload" * 100
+        handle = _handle_in(store_artifact(FileArtifact(data=data)))
+        scheme, _, hex_part = handle.rpartition("/")
+        upper = f"{scheme}/{hex_part.upper()}"
+        assert upper != handle
+        assert base64.b64decode(resolve_artifact_handles(upper)) == data
+
     def test_resolves_handle_inside_dict(self) -> None:
         data = b"binary-payload" * 1000
         handle = _handle_in(store_artifact(FileArtifact(data=data)))