diff --git a/app/src/main/kotlin/org/stypox/dicio/skills/calculator/CalculatorSkill.kt b/app/src/main/kotlin/org/stypox/dicio/skills/calculator/CalculatorSkill.kt
index c2927d1c..d0d4f12c 100644
--- a/app/src/main/kotlin/org/stypox/dicio/skills/calculator/CalculatorSkill.kt
+++ b/app/src/main/kotlin/org/stypox/dicio/skills/calculator/CalculatorSkill.kt
@@ -7,6 +7,7 @@ import org.dicio.skill.skill.SkillInfo
 import org.dicio.skill.skill.SkillOutput
 import org.dicio.skill.standard.StandardRecognizerData
 import org.dicio.skill.standard.StandardRecognizerSkill
+import org.dicio.skill.standard.util.MatchHelper
 import org.stypox.dicio.sentences.Sentences.Calculator
 import org.stypox.dicio.sentences.Sentences.CalculatorOperators
 import java.text.DecimalFormat
@@ -20,7 +21,8 @@ class CalculatorSkill(correspondingSkillInfo: SkillInfo, data: StandardRecognize
         operatorSection: StandardRecognizerData<CalculatorOperators>,
         text: String
     ): CalculatorOperators? {
-        val (score, result) = operatorSection.score(ctx, text)
+        val helper = MatchHelper(ctx.parserFormatter, text)
+        val (score, result) = operatorSection.score(helper, text)
         return if (score.scoreIn01Range() < 0.3) {
             null
         } else {
diff --git a/skill/src/main/java/org/dicio/skill/standard/StandardRecognizerData.kt b/skill/src/main/java/org/dicio/skill/standard/StandardRecognizerData.kt
index 1bce4076..7c5cb36a 100644
--- a/skill/src/main/java/org/dicio/skill/standard/StandardRecognizerData.kt
+++ b/skill/src/main/java/org/dicio/skill/standard/StandardRecognizerData.kt
@@ -3,6 +3,7 @@ package org.dicio.skill.standard
 import org.dicio.skill.context.SkillContext
 import org.dicio.skill.skill.Specificity
 import org.dicio.skill.standard.construct.Construct
+import org.dicio.skill.standard.util.MatchHelper
 import org.dicio.skill.standard.util.initialMemToEnd
 
 open class StandardRecognizerData<out T>(
@@ -11,7 +12,10 @@ open class StandardRecognizerData<out T>(
     private val sentencesWithId: List<Pair<String, Construct>>,
 ) {
     fun score(ctx: SkillContext, input: String): Pair<StandardScore, T> {
-        val helper = ctx.standardMatchHelper!! // surely != null, see its javadoc
+        return score(ctx.standardMatchHelper!!, input)
+    }
+
+    fun score(helper: MatchHelper, input: String): Pair<StandardScore, T> {
         val cumulativeWeight = helper.cumulativeWeight
 
         var bestRes: Pair<String, StandardScore>? = null
diff --git a/skill/src/test/java/org/dicio/skill/standard/StandardRecognizerDataTest.kt b/skill/src/test/java/org/dicio/skill/standard/StandardRecognizerDataTest.kt
new file mode 100644
index 00000000..a82c6011
--- /dev/null
+++ b/skill/src/test/java/org/dicio/skill/standard/StandardRecognizerDataTest.kt
@@ -0,0 +1,51 @@
+package org.dicio.skill.standard
+
+import io.kotest.core.spec.style.StringSpec
+import io.kotest.matchers.shouldNotBe
+import org.dicio.skill.skill.Specificity
+import org.dicio.skill.standard.construct.WordConstruct
+import org.dicio.skill.standard.construct.CompositeConstruct
+import org.dicio.skill.standard.util.MatchHelper
+
+/**
+ * Regression test: StandardRecognizerData.score(MatchHelper, input) must work
+ * without ctx.standardMatchHelper being set. This is needed when skills call
+ * score() during generateOutput (e.g. CalculatorSkill matching operators).
+ */
+class StandardRecognizerDataTest : StringSpec({
+
+    "score with explicit MatchHelper does not require ctx" {
+        // Build a simple recognizer that matches the word "plus"
+        val construct = CompositeConstruct(
+            listOf(WordConstruct("plus", false, false, 1.0f))
+        )
+        val data = StandardRecognizerData(
+            specificity = Specificity.HIGH,
+            converter = { input, sentenceId, _ -> sentenceId },
+            sentencesWithId = listOf(Pair("plus_sentence", construct)),
+        )
+
+        val helper = MatchHelper(parserFormatter = null, userInput = "plus")
+        val (score, result) = data.score(helper, "plus")
+
+        score shouldNotBe null
+        result shouldNotBe null
+    }
+
+    "score with explicit MatchHelper returns low score for non-matching input" {
+        val construct = CompositeConstruct(
+            listOf(WordConstruct("plus", false, false, 1.0f))
+        )
+        val data = StandardRecognizerData(
+            specificity = Specificity.HIGH,
+            converter = { input, sentenceId, _ -> sentenceId },
+            sentencesWithId = listOf(Pair("plus_sentence", construct)),
+        )
+
+        val helper = MatchHelper(parserFormatter = null, userInput = "banana")
+        val (score, _) = data.score(helper, "banana")
+
+        // should score poorly since "banana" doesn't match "plus"
+        assert(score.scoreIn01Range() < 0.5f)
+    }
+})