diff --git a/src/BaselineOfMooseRuleEngine/BaselineOfMooseRuleEngine.class.st b/src/BaselineOfMooseRuleEngine/BaselineOfMooseRuleEngine.class.st
index 3526b86..5535161 100644
--- a/src/BaselineOfMooseRuleEngine/BaselineOfMooseRuleEngine.class.st
+++ b/src/BaselineOfMooseRuleEngine/BaselineOfMooseRuleEngine.class.st
@@ -21,25 +21,26 @@ BaselineOfMooseRuleEngine >> defineDependencies: spec [
 	spec
 		baseline: 'Mocketry'
 		with: [ spec repository: 'github://dionisiydk/Mocketry' ].
-		
+
 	spec
 		baseline: 'LLMAPI'
 		with: [ spec repository: 'github://Evref-BL/Pharo-LLMAPI:main/src' ].
-		
-	spec 
-	baseline: 'SonarqubePharoAPI'
+
+	spec
+		baseline: 'SonarqubePharoAPI'
 		with: [
-			spec repository: 'github://Evref-BL/Sonarqube-Pharo-API:develop' ].
+		spec repository: 'github://Evref-BL/Sonarqube-Pharo-API:develop' ].
 
 	spec baseline: 'FASTJava' with: [
 		spec
 			repository: 'github://moosetechnology/FAST-Java:v3/src';
-			loads: #( 'smacc' ) ].	
-
+			loads: #( 'smacc' ) ]
 ]
 
 { #category : 'groups' }
 BaselineOfMooseRuleEngine >> defineGroups: spec [
+
+	
 ]
 
 { #category : 'packages' }
@@ -47,8 +48,8 @@ BaselineOfMooseRuleEngine >> definePackages: spec [
 
 	spec
 		package: 'MooseRuleEngine'
-		with: [ spec requires: #( 'LLMAPI' 'SonarqubePharoAPI' 'FASTJava' ) ].
+		with: [ spec requires: #( 'LLMAPI' 'SonarqubePharoAPI' ) ].
 	spec
 		package: 'MooseRuleEngine-Tests'
-		with: [ spec requires: #( 'MooseRuleEngine' 'Mocketry' ) ]
+		with: [ spec requires: #( 'MooseRuleEngine' 'Mocketry' 'FASTJava' ) ]
 ]
diff --git a/src/MooseRuleEngine-Tests/MRERuleTest.class.st b/src/MooseRuleEngine-Tests/MRERuleTest.class.st
index c966b42..d7edca7 100644
--- a/src/MooseRuleEngine-Tests/MRERuleTest.class.st
+++ b/src/MooseRuleEngine-Tests/MRERuleTest.class.st
@@ -8,6 +8,18 @@ Class {
 	#package : 'MooseRuleEngine-Tests'
 }
 
+{ #category : 'tests' }
+MRERuleTest >> testDoesNotApplyWithoutSupportedExtensions [
+
+	| rule file |
+	rule := MRERule new.
+	file := MREFile new
+		        path: 'test.java';
+		        content: 'content'.
+
+	self deny: (rule appliesToFile: file)
+]
+
 { #category : 'tests' }
 MRERuleTest >> testGetHelper [
 
diff --git a/src/MooseRuleEngine-Tests/MooseRuleEngineTest.class.st b/src/MooseRuleEngine-Tests/MooseRuleEngineTest.class.st
index 906720a..382ea97 100644
--- a/src/MooseRuleEngine-Tests/MooseRuleEngineTest.class.st
+++ b/src/MooseRuleEngine-Tests/MooseRuleEngineTest.class.st
@@ -71,6 +71,44 @@ MooseRuleEngineTest >> testDetectAndFix [
 	self assert: result size equals: 1
 ]
 
+{ #category : 'tests' }
+MooseRuleEngineTest >> testDetectIgnoresUnsupportedFiles [
+
+	| violations |
+	ruleEngine rules: { rule1 }.
+	ruleEngine files: {
+			file1.
+			file2 }.
+
+	violations := ruleEngine detect.
+
+	self assert: violations size equals: 1.
+	self assert: violations first rule equals: rule1
+]
+
+{ #category : 'tests' }
+MooseRuleEngineTest >> testDetectMixedRuleTypes [
+
+	| javaRule violations |
+	javaRule := RuleMockJava new.
+	ruleEngine rules: {
+			rule1.
+			javaRule }.
+	ruleEngine files: {
+			file1.
+			file2 }.
+
+	violations := ruleEngine detect.
+
+	self assert: violations size equals: 2.
+	self
+		assertCollection:
+		(violations collect: [ :violation | violation rule ])
+		hasSameElements: {
+				rule1.
+				javaRule }
+]
+
 { #category : 'tests' }
 MooseRuleEngineTest >> testDetectWithoutFiles [
 
diff --git a/src/MooseRuleEngine-Tests/RuleMock1.class.st b/src/MooseRuleEngine-Tests/RuleMock1.class.st
index 0571647..65816a3 100644
--- a/src/MooseRuleEngine-Tests/RuleMock1.class.st
+++ b/src/MooseRuleEngine-Tests/RuleMock1.class.st
@@ -20,3 +20,9 @@ RuleMock1 >> fix: violation [
 	fix := MREFix new.
 	^ { fix }
 ]
+
+{ #category : 'accessing' }
+RuleMock1 >> supportedExtensions [
+
+	^ #( 'ts' )
+]
diff --git a/src/MooseRuleEngine-Tests/RuleMockJava.class.st b/src/MooseRuleEngine-Tests/RuleMockJava.class.st
new file mode 100644
index 0000000..a175f19
--- /dev/null
+++ b/src/MooseRuleEngine-Tests/RuleMockJava.class.st
@@ -0,0 +1,12 @@
+Class {
+	#name : 'RuleMockJava',
+	#superclass : 'RuleMock1',
+	#category : 'MooseRuleEngine-Tests',
+	#package : 'MooseRuleEngine-Tests'
+}
+
+{ #category : 'accessing' }
+RuleMockJava >> supportedExtensions [
+
+	^ #( 'java' )
+]
diff --git a/src/MooseRuleEngine/BaselineOfMooseRuleEngine.class.st b/src/MooseRuleEngine/BaselineOfMooseRuleEngine.class.st
deleted file mode 100644
index 18a1488..0000000
--- a/src/MooseRuleEngine/BaselineOfMooseRuleEngine.class.st
+++ /dev/null
@@ -1,51 +0,0 @@
-Class {
-	#name : 'BaselineOfMooseRuleEngine',
-	#superclass : 'Object',
-	#category : 'MooseRuleEngine',
-	#package : 'MooseRuleEngine'
-}
-
-{ #category : 'baselines' }
-BaselineOfMooseRuleEngine >> baseline: spec [
-
-	<baseline>
-	spec for: #common do: [
-		self defineDependencies: spec.
-		self definePackages: spec.
-		self defineGroups: spec ]
-]
-
-{ #category : 'dependencies' }
-BaselineOfMooseRuleEngine >> defineDependencies: spec [
-
-	spec
-		baseline: 'Mocketry'
-		with: [ spec repository: 'github://dionisiydk/Mocketry' ].
-		
-	spec
-		baseline: 'LLMAPI'
-		with: [ spec repository: 'github://Evref-BL/Pharo-LLMAPI:main/src' ].
-		
-	spec 
-	baseline: 'SonarqubePharoAPI'
-		with: [
-			spec repository: 'github://Evref-BL/Sonarqube-Pharo-API:develop' ].
-
-
-
-]
-
-{ #category : 'groups' }
-BaselineOfMooseRuleEngine >> defineGroups: spec [
-]
-
-{ #category : 'packages' }
-BaselineOfMooseRuleEngine >> definePackages: spec [
-
-	spec
-		package: 'MooseRuleEngine'
-		with: [ spec requires: #( 'LLMAPI' 'SonarqubePharoAPI' ) ].
-	spec
-		package: 'MooseRuleEngine-Tests'
-		with: [ spec requires: #( 'MooseRuleEngine' 'Mocketry' ) ]
-]
diff --git a/src/MooseRuleEngine/MRERule.class.st b/src/MooseRuleEngine/MRERule.class.st
index d36a7bc..92878ed 100644
--- a/src/MooseRuleEngine/MRERule.class.st
+++ b/src/MooseRuleEngine/MRERule.class.st
@@ -18,6 +18,13 @@ MRERule >> analyse: file [
 	^self subclassResponsibility 
 ]
 
+{ #category : 'testing' }
+MRERule >> appliesToFile: file [
+
+	^ self supportedExtensions includes:
+		  file path asFileReference extension asLowercase
+]
+
 { #category : 'accessing' }
 MRERule >> description [
 
@@ -87,3 +94,9 @@ MRERule >> name: anObject [
 
 	name := anObject
 ]
+
+{ #category : 'accessing' }
+MRERule >> supportedExtensions [
+
+	^ #(  )
+]
diff --git a/src/MooseRuleEngine/MooseRuleEngine.class.st b/src/MooseRuleEngine/MooseRuleEngine.class.st
index 5e0dced..7006b27 100644
--- a/src/MooseRuleEngine/MooseRuleEngine.class.st
+++ b/src/MooseRuleEngine/MooseRuleEngine.class.st
@@ -19,13 +19,13 @@ MooseRuleEngine >> addHelper: helper [
 
 { #category : 'as yet unclassified' }
 MooseRuleEngine >> detect [
+
 	| violations |
 	violations := rules collect: [ :rule |
-		files collect: [ :file | rule analyse: file ].
-	].
+		              (files select: [ :file | rule appliesToFile: file ])
+			              collect: [ :file | rule analyse: file ] ].
 
-	^ violations flattened 
-	
+	^ violations flattened
 ]
 
 { #category : 'as yet unclassified' }
diff --git a/src/MooseRuleEngine/TJavaRule.trait.st b/src/MooseRuleEngine/TJavaRule.trait.st
new file mode 100644
index 0000000..514ae12
--- /dev/null
+++ b/src/MooseRuleEngine/TJavaRule.trait.st
@@ -0,0 +1,11 @@
+Trait {
+	#name : 'TJavaRule',
+	#category : 'MooseRuleEngine',
+	#package : 'MooseRuleEngine'
+}
+
+{ #category : 'accessing' }
+TJavaRule >> supportedExtensions [
+
+	^ #( 'java' )
+]
diff --git a/src/MooseRuleEngine/TTypescriptRule.trait.st b/src/MooseRuleEngine/TTypescriptRule.trait.st
new file mode 100644
index 0000000..edfcec4
--- /dev/null
+++ b/src/MooseRuleEngine/TTypescriptRule.trait.st
@@ -0,0 +1,11 @@
+Trait {
+	#name : 'TTypescriptRule',
+	#category : 'MooseRuleEngine',
+	#package : 'MooseRuleEngine'
+}
+
+{ #category : 'accessing' }
+TTypescriptRule >> supportedExtensions [
+
+	^ #( 'ts' )
+]