diff --git a/evaluate.py b/evaluate.py
index 9d11f8f..d3831f0 100644
--- a/evaluate.py
+++ b/evaluate.py
@@ -718,9 +718,10 @@ def evaluate_interface_modules(files: list[SourceFile]) -> list[Violation]:
 def evaluate_shell_modules(files: list[SourceFile]) -> list[Violation]:
     core_handler_references_by_domain: dict[str, set[str]] = {}
     for source_file in files:
-        if source_file.metadata.module_type == "core":
+        if source_file.metadata.module_type == "core" and source_file.module_name:
             core_handler_references_by_domain.setdefault(source_file.metadata.domain, set()).update(
-                source_file.decision_surface | source_file.decision_products
+                f"{source_file.module_name}.{reference}"
+                for reference in source_file.decision_surface | source_file.decision_products
             )
 
     violations: list[Violation] = []
@@ -728,7 +729,7 @@ def evaluate_shell_modules(files: list[SourceFile]) -> list[Violation]:
         if source_file.metadata.module_type != "shell":
             continue
         core_references = core_handler_references_by_domain.get(source_file.metadata.domain, set())
-        if not source_file.api_references.intersection(core_references):
+        if not source_file.qualified_references.intersection(core_references):
             violations.append(Violation(source_file.path, "shell module must reference a core API in the same @archlint.domain"))
     return violations
 
diff --git a/evaluate_test.py b/evaluate_test.py
index 1850747..dc6b9e3 100644
--- a/evaluate_test.py
+++ b/evaluate_test.py
@@ -336,6 +336,7 @@ def test_shell_module_does_not_accept_arbitrary_core_type_reference(self):
             path="/repo/Handler.swift",
             metadata={"moduleType": "shell", "domain": "mail.sync", "exemptReason": ""},
             apiReferences=["CoreVocabulary"],
+            qualifiedReferences=["Core.CoreVocabulary"],
         )
 
         violations = evaluate.evaluate([core, shell])
@@ -359,6 +360,7 @@ def test_shell_module_accepts_core_decision_product_reference(self):
             path="/repo/Handler.swift",
             metadata={"moduleType": "shell", "domain": "mail.sync", "exemptReason": ""},
             apiReferences=["SyncPlan"],
+            qualifiedReferences=["Core.SyncPlan"],
             identifiers=["EffectType"],
             effectfulIdentifiers=["EffectType"],
             decisionSurface=[],
@@ -382,6 +384,50 @@ def test_shell_module_accepts_core_decision_product_reference(self):
 
         self.assertEqual([], violations)
 
+    def test_shell_module_does_not_accept_same_named_bare_core_reference(self):
+        core = source_file(path="/repo/Core.swift")
+        shell = source_file(
+            path="/repo/Handler.swift",
+            metadata={"moduleType": "shell", "domain": "mail.sync", "exemptReason": ""},
+            identifiers=["decideSync", "EffectType"],
+            apiReferences=["decideSync"],
+            qualifiedReferences=[],
+            effectfulIdentifiers=["EffectType"],
+        )
+
+        violations = evaluate.evaluate([core, shell])
+
+        self.assertIn(
+            "shell module must reference a core API in the same @archlint.domain",
+            [violation.message for violation in violations],
+        )
+
+    def test_shell_module_accepts_qualified_core_decision_reference(self):
+        core = source_file(path="/repo/Core.swift")
+        shell = source_file(
+            path="/repo/Handler.swift",
+            metadata={"moduleType": "shell", "domain": "mail.sync", "exemptReason": ""},
+            identifiers=["decideSync", "EffectType"],
+            apiReferences=["decideSync"],
+            qualifiedReferences=["Core.decideSync"],
+            effectfulIdentifiers=["EffectType"],
+        )
+        test = source_file(
+            path="/repo/CoreTests.swift",
+            testScope="CoreTests",
+            metadata={"moduleType": "test", "domain": "mail.sync", "exemptReason": ""},
+            apiReferences=["decideSync"],
+            propertyChecks=[property_check(["decideSync"])],
+            decisionSurface=[],
+            propertyTestSurface=[],
+            decisionProducts=[],
+            decisionReferences=[],
+        )
+
+        violations = evaluate.evaluate([core, shell, test])
+
+        self.assertEqual([], violations)
+
     def test_shell_module_must_touch_effectful_api(self):
         core = source_file(
             path="/repo/Core.swift",
diff --git a/go/main_test.go b/go/main_test.go
index 6eb5ea5..c8eb8eb 100644
--- a/go/main_test.go
+++ b/go/main_test.go
@@ -53,17 +53,17 @@ func parseViolationOutput(output string) []violation {
 
 func TestLintBackendArchitectureAcceptsHandlerWithDecisionModule(t *testing.T) {
 	backendRoot := newBackendFixture(t, map[string]string{
-		"internal/auth/auth_decision.go": `// @archlint.module core
+		"internal/auth/decision/auth_decision.go": `// @archlint.module core
 // @archlint.domain auth
-package auth
+package decision
 
 func DecideTokenClaims(subject string) bool {
 	return subject != ""
 }
 `,
-		"internal/auth/auth_decision_test.go": `// @archlint.module test
+		"internal/auth/decision/auth_decision_test.go": `// @archlint.module test
 // @archlint.domain auth
-package auth
+package decision
 
 import (
 	"testing"
@@ -83,10 +83,13 @@ func TestDecideTokenClaimsProperty(t *testing.T) {
 // @archlint.domain auth
 package auth
 
-import "net/http"
+import (
+	"archlintfixture/internal/auth/decision"
+	"net/http"
+)
 
 func Handle() string {
-	if DecideTokenClaims(http.MethodGet) {
+	if decision.DecideTokenClaims(http.MethodGet) {
 		return http.MethodGet
 	}
 	return ""
@@ -344,9 +347,9 @@ func Route(_ CoreVocabulary) string {
 
 func TestLintBackendArchitectureAcceptsHandlerWithCoreDecisionProductReference(t *testing.T) {
 	backendRoot := newBackendFixture(t, map[string]string{
-		"internal/httpapi/http_decision.go": `// @archlint.module core
+		"internal/httpapi/decision/http_decision.go": `// @archlint.module core
 // @archlint.domain http-api
-package httpapi
+package decision
 
 type RoutePlan struct{}
 
@@ -357,9 +360,9 @@ func DecideRoute(input bool) RoutePlan {
 	return RoutePlan{}
 }
 `,
-		"internal/httpapi/http_decision_test.go": `// @archlint.module test
+		"internal/httpapi/decision/http_decision_test.go": `// @archlint.module test
 // @archlint.domain http-api
-package httpapi
+package decision
 
 import (
 	"testing"
@@ -380,9 +383,12 @@ func TestDecideRouteProperty(t *testing.T) {
 // @archlint.domain http-api
 package httpapi
 
-import "net/http"
+import (
+	"archlintfixture/internal/httpapi/decision"
+	"net/http"
+)
 
-func Route(_ RoutePlan) string {
+func Route(_ decision.RoutePlan) string {
 	return http.MethodGet
 }
 `,
diff --git a/swift/Sources/SwiftArchLint/main.swift b/swift/Sources/SwiftArchLint/main.swift
index 5fb9dcf..0a45ee7 100644
--- a/swift/Sources/SwiftArchLint/main.swift
+++ b/swift/Sources/SwiftArchLint/main.swift
@@ -411,7 +411,7 @@ enum SwiftArchLint {
         }
       )
       for occurrence: SymbolOccurrence in occurrences {
-        guard occurrence.roles.contains(.reference),
+        guard (occurrence.roles.contains(.reference) || occurrence.roles.contains(.call)),
           occurrence.symbol.language == .swift,
           !occurrence.location.isSystem
         else {
diff --git a/swift/test.sh b/swift/test.sh
index 5c1b9f1..1dd7f0d 100644
--- a/swift/test.sh
+++ b/swift/test.sh
@@ -672,12 +672,12 @@ import Foundation
 
 struct HTTPMailBackendClient {
   func add() -> URLRequest {
-    _ = HTTPMailBackendDecider.decide()
     return URLRequest(url: URL(string: "http://localhost")!)
   }
 }
 EOF
-assert_passes "$core_enum_case_matching_shell_method_fixture"
+assert_fails_with "$core_enum_case_matching_shell_method_fixture" \
+  "shell module must reference a core API in the same @archlint.domain"
 
 empty_decider_fixture="$(new_fixture empty-decider)"
 cat > "$empty_decider_fixture/apps/ios/MailApp/Backend/SQLiteMailSyncStateDecider.swift" <<'EOF'