fix: externalize usecase matcher prompt

arc-assistants/src/main/kotlin/extensions/UseCasePromptProvider.kt

@@ -0,0 +1,21 @@
+// SPDX-FileCopyrightText: 2025 Deutsche Telekom AG and others
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.eclipse.lmos.arc.assistants.support.extensions
+
+import org.eclipse.lmos.arc.agents.dsl.DSLContext
+
+/**
+ * Builds the system prompt for [org.eclipse.lmos.arc.assistants.support.filters.UseCaseMatcher].
+ *
+ * Register an implementation as a Spring bean (or via [org.eclipse.lmos.arc.agents.dsl.BeanProvider])
+ * to override the default classification prompt at runtime.
+ */
+fun interface UseCasePromptProvider {
+    /**
+     * @param useCases Formatted use case definitions passed to the matcher LLM call.
+     * @param context Current DSL context (e.g. for loading external prompt files).
+     */
+    suspend fun buildSystemPrompt(useCases: String, context: DSLContext): String
+}

arc-assistants/src/main/kotlin/filters/UseCaseMatcher.kt

@@ -6,6 +6,8 @@ package org.eclipse.lmos.arc.assistants.support.filters
 
 import org.eclipse.lmos.arc.agents.dsl.DSLContext
 import org.eclipse.lmos.arc.agents.dsl.extensions.llm
+import org.eclipse.lmos.arc.agents.dsl.getOptional
+import org.eclipse.lmos.arc.assistants.support.extensions.UseCasePromptProvider
 import org.eclipse.lmos.arc.core.getOrNull
 import org.eclipse.lmos.arc.core.onFailure
 import org.slf4j.LoggerFactory
@@ -14,101 +16,16 @@ class UseCaseMatcher(private val model: String? = null) {
 
     private val log = LoggerFactory.getLogger(this.javaClass)
 
-    private fun system(useCases: String) = """
-    You are a classification system.
-
-    Your task is to match an assistant message to the most appropriate use case, 
-    based on the provided use case definitions and their solutions.
-
-    ## Rules
-    Each use case includes a Solution, describing the expected assistant behavior.
-    Match based on semantic meaning, not exact wording.
-    Prefer the use case whose solution best aligns with the intent of the assistant message.
-    If no use case clearly matches, return <UNKNOWN>.
-    Output must be only one label in angle brackets.
-
-    ----
-
-    ## Examples
-
-    ### Example 1
-    UseCases
-    UseCase: password_reset
-    Solution
-    Ask the customer to restart their router to reset their router.
-
-    #### UseCase: password_forgotton
-    Solution
-    Ask the customer to send an email to customer support.
-
-    Assistant
-    Please restart your router.
-
-    Output:<password_reset>
-
-    ### Example 2
-    UseCases
-    UseCase: billing_issue
-    Solution
-    Ask the customer to check their invoice or contact billing support.
-
-    UseCase: technical_issue
-    Solution
-    Guide the customer through troubleshooting steps.
-
-    Assistant
-    Please review your invoice or reach out to billing support.
-
-    Output: <billing_issue>
-
-    ### Example 3
-    UseCases
-    UseCase: account_locked
-    Solution
-    Tell the customer to wait 15 minutes before trying again.
-
-    UseCase: password_reset
-    Solution
-    Ask the customer to reset their password using the reset link.
-
-    Assistant
-    You can reset your password using the link we sent you.
-
-    Output: <password_reset>
-
-    ### Example 4 (No Match)
-    UseCases
-    UseCase: shipping_delay
-    Solution
-    Inform the customer about delayed delivery.
-
-    UseCase: refund_request
-    Solution
-    Guide the customer through requesting a refund.
-
-    Assistant
-    Our office hours are Monday to Friday, 9am–5pm.
-
-    Output: <UNKNOWN>
-
-    ----
-
-    Now classify:
-
-    #UseCases
-    $useCases
-
-
-    Output: (only the label in angle brackets)
-    """
-
     suspend fun matchUseCase(
         message: String,
         useCases: String,
         context: DSLContext
     ): String? {
+        val systemPrompt = context.getOptional<UseCasePromptProvider>()
+            ?.buildSystemPrompt(useCases, context)
+            ?: UseCaseMatcherPrompts.build(useCases)
         val result = context.llm(
-            system = system(useCases),
+            system = systemPrompt,
             user = "Assistant Message: $message",
             model = model
         ).onFailure {
@@ -122,4 +39,4 @@ class UseCaseMatcher(private val model: String? = null) {
         log.info("Matched UseCase found: $result")
         return useCase
     }
-}
+}

arc-assistants/src/main/kotlin/filters/UseCaseMatcherPrompts.kt

@@ -0,0 +1,101 @@
+// SPDX-FileCopyrightText: 2025 Deutsche Telekom AG and others
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.eclipse.lmos.arc.assistants.support.filters
+
+/**
+ * Default system prompt template for [UseCaseMatcher].
+ * Replace `{useCases}` with the formatted use case definitions at runtime.
+ */
+object UseCaseMatcherPrompts {
+    const val TEMPLATE = """
+    You are a classification system.
+
+    Your task is to match an assistant message to the most appropriate use case, 
+    based on the provided use case definitions and their solutions.
+
+    ## Rules
+    Each use case includes a Solution, describing the expected assistant behavior.
+    Match based on semantic meaning, not exact wording.
+    Prefer the use case whose solution best aligns with the intent of the assistant message.
+    If no use case clearly matches, return <UNKNOWN>.
+    Output must be only one label in angle brackets.
+
+    ----
+
+    ## Examples
+
+    ### Example 1
+    UseCases
+    UseCase: password_reset
+    Solution
+    Ask the customer to restart their router to reset their router.
+
+    #### UseCase: password_forgotton
+    Solution
+    Ask the customer to send an email to customer support.
+
+    Assistant
+    Please restart your router.
+
+    Output:<password_reset>
+
+    ### Example 2
+    UseCases
+    UseCase: billing_issue
+    Solution
+    Ask the customer to check their invoice or contact billing support.
+
+    UseCase: technical_issue
+    Solution
+    Guide the customer through troubleshooting steps.
+
+    Assistant
+    Please review your invoice or reach out to billing support.
+
+    Output: <billing_issue>
+
+    ### Example 3
+    UseCases
+    UseCase: account_locked
+    Solution
+    Tell the customer to wait 15 minutes before trying again.
+
+    UseCase: password_reset
+    Solution
+    Ask the customer to reset their password using the reset link.
+
+    Assistant
+    You can reset your password using the link we sent you.
+
+    Output: <password_reset>
+
+    ### Example 4 (No Match)
+    UseCases
+    UseCase: shipping_delay
+    Solution
+    Inform the customer about delayed delivery.
+
+    UseCase: refund_request
+    Solution
+    Guide the customer through requesting a refund.
+
+    Assistant
+    Our office hours are Monday to Friday, 9am–5pm.
+
+    Output: <UNKNOWN>
+
+    ----
+
+    Now classify:
+
+    #UseCases
+    {useCases}
+
+
+    Output: (only the label in angle brackets)
+    """
+
+    fun build(useCases: String): String = TEMPLATE.replace("{useCases}", useCases)
+}