fix(classification): resolve keyword matching failures in E2E tests (#713)

Fixes two critical bugs causing keyword routing E2E test failures:

1. **Config merge bug**: Embedded struct assignment in reconciler didn't copy
   IntelligentRouting fields correctly. Changed to explicit field-by-field copy
   to ensure keyword rules are properly loaded from CRDs.

2. **Cache hit headers bug**: Cache responses used ImmediateResponse which
   bypassed normal header processing, causing VSR decision headers to be missing.
   Added vsrDecisionName parameter to CreateCacheHitResponse() to include
   x-vsr-selected-decision header in cached responses.

**Test Results:**
- keyword-routing: 16.67% -> 100%
- rule-condition-logic: 33.33% -> 83.33% (remaining failure is unrelated)

Fixes #713

Signed-off-by: Srinivas A <56465971+srini-abhiram@users.noreply.github.com>

Author: srini-abhiram

src/semantic-router/pkg/extproc/req_filter_cache.go

@@ -60,6 +60,13 @@ func (r *OpenAIRouter) handleCaching(ctx *RequestContext, categoryName string) (
 		} else if found {
 			// Mark this request as a cache hit
 			ctx.VSRCacheHit = true
+
+			// Set VSR decision context even for cache hits so headers are populated
+			// The categoryName passed here is the decision name from classification
+			if categoryName != "" {
+				ctx.VSRSelectedDecisionName = categoryName
+			}
+
 			// Log cache hit
 			logging.LogEvent("cache_hit", map[string]interface{}{
 				"request_id": ctx.RequestID,
@@ -69,7 +76,7 @@ func (r *OpenAIRouter) handleCaching(ctx *RequestContext, categoryName string) (
 				"threshold":  threshold,
 			})
 			// Return immediate response from cache
-			response := http.CreateCacheHitResponse(cachedResponse, ctx.ExpectStreamingResponse)
+			response := http.CreateCacheHitResponse(cachedResponse, ctx.ExpectStreamingResponse, categoryName)
 			ctx.TraceContext = spanCtx
 			return response, true
 		}

src/semantic-router/pkg/k8s/reconciler.go

@@ -259,7 +259,15 @@ func (r *Reconciler) validateAndUpdate(ctx context.Context, pool *v1alpha1.Intel
 	// Create new config by merging with static config
 	newConfig := *r.staticConfig
 	newConfig.BackendModels = *backendModels
-	newConfig.IntelligentRouting = *intelligentRouting
+
+	// Copy IntelligentRouting fields explicitly (since it's embedded with ,inline in YAML)
+	// Assigning the whole struct doesn't work correctly with embedded structs
+	newConfig.KeywordRules = intelligentRouting.KeywordRules
+	newConfig.EmbeddingRules = intelligentRouting.EmbeddingRules
+	newConfig.Categories = intelligentRouting.Categories
+	newConfig.Decisions = intelligentRouting.Decisions
+	newConfig.Strategy = intelligentRouting.Strategy
+	newConfig.ReasoningConfig = intelligentRouting.ReasoningConfig
 
 	// Call update callback
 	if r.onConfigUpdate != nil {

src/semantic-router/pkg/utils/http/response.go

@@ -233,7 +233,7 @@ func CreateJailbreakViolationResponse(jailbreakType string, confidence float32,
 }
 
 // CreateCacheHitResponse creates an immediate response from cache
-func CreateCacheHitResponse(cachedResponse []byte, isStreaming bool) *ext_proc.ProcessingResponse {
+func CreateCacheHitResponse(cachedResponse []byte, isStreaming bool, vsrDecisionName string) *ext_proc.ProcessingResponse {
 	var responseBody []byte
 	var contentType string
 
@@ -283,25 +283,38 @@ func CreateCacheHitResponse(cachedResponse []byte, isStreaming bool) *ext_proc.P
 		responseBody = cachedResponse
 	}
 
+	// Build headers including VSR decision headers for cache hits
+	setHeaders := []*core.HeaderValueOption{
+		{
+			Header: &core.HeaderValue{
+				Key:      "content-type",
+				RawValue: []byte(contentType),
+			},
+		},
+		{
+			Header: &core.HeaderValue{
+				Key:      headers.VSRCacheHit,
+				RawValue: []byte("true"),
+			},
+		},
+	}
+
+	// Add VSR decision header if provided
+	if vsrDecisionName != "" {
+		setHeaders = append(setHeaders, &core.HeaderValueOption{
+			Header: &core.HeaderValue{
+				Key:      headers.VSRSelectedDecision,
+				RawValue: []byte(vsrDecisionName),
+			},
+		})
+	}
+
 	immediateResponse := &ext_proc.ImmediateResponse{
 		Status: &typev3.HttpStatus{
 			Code: typev3.StatusCode_OK,
 		},
 		Headers: &ext_proc.HeaderMutation{
-			SetHeaders: []*core.HeaderValueOption{
-				{
-					Header: &core.HeaderValue{
-						Key:      "content-type",
-						RawValue: []byte(contentType),
-					},
-				},
-				{
-					Header: &core.HeaderValue{
-						Key:      headers.VSRCacheHit,
-						RawValue: []byte("true"),
-					},
-				},
-			},
+			SetHeaders: setHeaders,
 		},
 		Body: responseBody,
 	}

src/semantic-router/pkg/utils/http/response_test.go

@@ -38,7 +38,7 @@ func TestCreateCacheHitResponse_NonStreaming(t *testing.T) {
 	}
 
 	// Test non-streaming response
-	response := CreateCacheHitResponse(cachedResponse, false)
+	response := CreateCacheHitResponse(cachedResponse, false, "test_decision")
 
 	// Verify response structure
 	if response == nil {
@@ -121,7 +121,7 @@ func TestCreateCacheHitResponse_Streaming(t *testing.T) {
 	}
 
 	// Test streaming response
-	response := CreateCacheHitResponse(cachedResponse, true)
+	response := CreateCacheHitResponse(cachedResponse, true, "test_decision")
 
 	// Verify response structure
 	if response == nil {
@@ -226,7 +226,7 @@ func TestCreateCacheHitResponse_StreamingWithInvalidJSON(t *testing.T) {
 	// Test with invalid JSON
 	invalidJSON := []byte("invalid json")
 
-	response := CreateCacheHitResponse(invalidJSON, true)
+	response := CreateCacheHitResponse(invalidJSON, true, "")
 
 	// Verify response structure
 	if response == nil {