diff --git a/relay/channel/api_request.go b/relay/channel/api_request.go
index c1954cc02..79eac3ad6 100644
--- a/relay/channel/api_request.go
+++ b/relay/channel/api_request.go
@@ -179,7 +179,7 @@ func processHeaderOverride(info *common.RelayInfo, c *gin.Context) (map[string]s
 	var passthroughRegex []*regexp.Regexp
 	if !info.IsChannelTest {
 		for k := range headerOverrideSource {
-			key := strings.TrimSpace(k)
+			key := strings.TrimSpace(strings.ToLower(k))
 			if key == "" {
 				continue
 			}
@@ -188,12 +188,11 @@ func processHeaderOverride(info *common.RelayInfo, c *gin.Context) (map[string]s
 				continue
 			}
 
-			lower := strings.ToLower(key)
 			var pattern string
 			switch {
-			case strings.HasPrefix(lower, headerPassthroughRegexPrefix):
+			case strings.HasPrefix(key, headerPassthroughRegexPrefix):
 				pattern = strings.TrimSpace(key[len(headerPassthroughRegexPrefix):])
-			case strings.HasPrefix(lower, headerPassthroughRegexPrefixV2):
+			case strings.HasPrefix(key, headerPassthroughRegexPrefixV2):
 				pattern = strings.TrimSpace(key[len(headerPassthroughRegexPrefixV2):])
 			default:
 				continue
@@ -234,7 +233,7 @@ func processHeaderOverride(info *common.RelayInfo, c *gin.Context) (map[string]s
 			if value == "" {
 				continue
 			}
-			headerOverride[name] = value
+			headerOverride[strings.ToLower(strings.TrimSpace(name))] = value
 		}
 	}
 
@@ -242,7 +241,7 @@ func processHeaderOverride(info *common.RelayInfo, c *gin.Context) (map[string]s
 		if isHeaderPassthroughRuleKey(k) {
 			continue
 		}
-		key := strings.TrimSpace(k)
+		key := strings.TrimSpace(strings.ToLower(k))
 		if key == "" {
 			continue
 		}
diff --git a/relay/channel/api_request_test.go b/relay/channel/api_request_test.go
index 84406ba48..f697f8555 100644
--- a/relay/channel/api_request_test.go
+++ b/relay/channel/api_request_test.go
@@ -53,7 +53,7 @@ func TestProcessHeaderOverride_ChannelTestSkipsClientHeaderPlaceholder(t *testin
 
 	headers, err := processHeaderOverride(info, ctx)
 	require.NoError(t, err)
-	_, ok := headers["X-Upstream-Trace"]
+	_, ok := headers["x-upstream-trace"]
 	require.False(t, ok)
 }
 
@@ -77,10 +77,10 @@ func TestProcessHeaderOverride_NonTestKeepsClientHeaderPlaceholder(t *testing.T)
 
 	headers, err := processHeaderOverride(info, ctx)
 	require.NoError(t, err)
-	require.Equal(t, "trace-123", headers["X-Upstream-Trace"])
+	require.Equal(t, "trace-123", headers["x-upstream-trace"])
 }
 
-func TestProcessHeaderOverride_RuntimeOverrideMergesWithChannelOverride(t *testing.T) {
+func TestProcessHeaderOverride_RuntimeOverrideIsFinalHeaderMap(t *testing.T) {
 	t.Parallel()
 
 	gin.SetMode(gin.TestMode)
@@ -92,8 +92,8 @@ func TestProcessHeaderOverride_RuntimeOverrideMergesWithChannelOverride(t *testi
 		IsChannelTest:             false,
 		UseRuntimeHeadersOverride: true,
 		RuntimeHeadersOverride: map[string]any{
-			"X-Static":  "runtime-value",
-			"X-Runtime": "runtime-only",
+			"x-static":  "runtime-value",
+			"x-runtime": "runtime-only",
 		},
 		ChannelMeta: &relaycommon.ChannelMeta{
 			HeadersOverride: map[string]any{
@@ -105,9 +105,10 @@ func TestProcessHeaderOverride_RuntimeOverrideMergesWithChannelOverride(t *testi
 
 	headers, err := processHeaderOverride(info, ctx)
 	require.NoError(t, err)
-	require.Equal(t, "runtime-value", headers["X-Static"])
-	require.Equal(t, "runtime-only", headers["X-Runtime"])
-	require.Equal(t, "legacy-only", headers["X-Legacy"])
+	require.Equal(t, "runtime-value", headers["x-static"])
+	require.Equal(t, "runtime-only", headers["x-runtime"])
+	_, exists := headers["x-legacy"]
+	require.False(t, exists)
 }
 
 func TestProcessHeaderOverride_PassthroughSkipsAcceptEncoding(t *testing.T) {
@@ -131,9 +132,9 @@ func TestProcessHeaderOverride_PassthroughSkipsAcceptEncoding(t *testing.T) {
 
 	headers, err := processHeaderOverride(info, ctx)
 	require.NoError(t, err)
-	require.Equal(t, "trace-123", headers["X-Trace-Id"])
+	require.Equal(t, "trace-123", headers["x-trace-id"])
 
-	_, hasAcceptEncoding := headers["Accept-Encoding"]
+	_, hasAcceptEncoding := headers["accept-encoding"]
 	require.False(t, hasAcceptEncoding)
 }
 
@@ -171,16 +172,17 @@ func TestProcessHeaderOverride_PassHeadersTemplateSetsRuntimeHeaders(t *testing.
 	_, err := relaycommon.ApplyParamOverrideWithRelayInfo([]byte(`{"model":"gpt-4.1"}`), info)
 	require.NoError(t, err)
 	require.True(t, info.UseRuntimeHeadersOverride)
-	require.Equal(t, "Codex CLI", info.RuntimeHeadersOverride["Originator"])
-	require.Equal(t, "sess-123", info.RuntimeHeadersOverride["Session_id"])
-	_, exists := info.RuntimeHeadersOverride["X-Codex-Beta-Features"]
+	require.Equal(t, "Codex CLI", info.RuntimeHeadersOverride["originator"])
+	require.Equal(t, "sess-123", info.RuntimeHeadersOverride["session_id"])
+	_, exists := info.RuntimeHeadersOverride["x-codex-beta-features"]
 	require.False(t, exists)
+	require.Equal(t, "legacy-value", info.RuntimeHeadersOverride["x-static"])
 
 	headers, err := processHeaderOverride(info, ctx)
 	require.NoError(t, err)
-	require.Equal(t, "Codex CLI", headers["Originator"])
-	require.Equal(t, "sess-123", headers["Session_id"])
-	_, exists = headers["X-Codex-Beta-Features"]
+	require.Equal(t, "Codex CLI", headers["originator"])
+	require.Equal(t, "sess-123", headers["session_id"])
+	_, exists = headers["x-codex-beta-features"]
 	require.False(t, exists)
 
 	upstreamReq := httptest.NewRequest(http.MethodPost, "https://example.com/v1/responses", nil)
diff --git a/relay/common/override.go b/relay/common/override.go
index 78cf60b92..95af8cfae 100644
--- a/relay/common/override.go
+++ b/relay/common/override.go
@@ -18,11 +18,8 @@ import (
 var negativeIndexRegexp = regexp.MustCompile(`\.(-\d+)`)
 
 const (
-	paramOverrideContextRequestHeaders           = "request_headers"
-	paramOverrideContextRequestHeadersRaw        = "request_headers_raw"
-	paramOverrideContextHeaderOverride           = "header_override"
-	paramOverrideContextHeaderOverrideNormalized = "header_override_normalized"
-	paramOverrideContextHeaderOverrideDeleted    = "header_override_deleted_normalized"
+	paramOverrideContextRequestHeaders = "request_headers"
+	paramOverrideContextHeaderOverride = "header_override"
 )
 
 var errSourceHeaderNotFound = errors.New("source header does not exist")
@@ -161,141 +158,118 @@ func getHeaderOverrideMap(info *RelayInfo) map[string]interface{} {
 	return info.ChannelMeta.HeadersOverride
 }
 
-func cloneHeaderOverrideMap(source map[string]interface{}) map[string]interface{} {
+func sanitizeHeaderOverrideMap(source map[string]interface{}) map[string]interface{} {
 	if len(source) == 0 {
 		return map[string]interface{}{}
 	}
 	target := make(map[string]interface{}, len(source))
 	for key, value := range source {
-		target[key] = value
+		normalizedKey := normalizeHeaderContextKey(key)
+		if normalizedKey == "" {
+			continue
+		}
+		normalizedValue := strings.TrimSpace(fmt.Sprintf("%v", value))
+		if normalizedValue == "" {
+			if isHeaderPassthroughRuleKeyForOverride(normalizedKey) {
+				target[normalizedKey] = ""
+			}
+			continue
+		}
+		target[normalizedKey] = normalizedValue
 	}
 	return target
 }
 
-func setHeaderOverrideEntry(target map[string]interface{}, key string, value interface{}) {
-	key = strings.TrimSpace(key)
+func isHeaderPassthroughRuleKeyForOverride(key string) bool {
+	key = strings.TrimSpace(strings.ToLower(key))
 	if key == "" {
-		return
-	}
-	for existing := range target {
-		if strings.EqualFold(strings.TrimSpace(existing), key) {
-			delete(target, existing)
-		}
-	}
-	target[key] = value
-}
-
-func isHeaderDeletedByRuntime(headerName string, deleted map[string]bool) bool {
-	if len(deleted) == 0 {
 		return false
 	}
-	normalized := normalizeHeaderContextKey(headerName)
-	if normalized == "" {
-		return false
+	if key == "*" {
+		return true
 	}
-	return deleted[normalized]
-}
-
-func mergeHeaderOverrideSource(base, runtime map[string]interface{}, deleted map[string]bool) map[string]interface{} {
-	merged := make(map[string]interface{}, len(base)+len(runtime))
-	for key, value := range base {
-		if isHeaderDeletedByRuntime(key, deleted) {
-			continue
-		}
-		setHeaderOverrideEntry(merged, key, value)
-	}
-	for key, value := range runtime {
-		setHeaderOverrideEntry(merged, key, value)
-	}
-	return merged
-}
-
-func cloneDeletedHeaderKeys(source map[string]bool) map[string]bool {
-	if len(source) == 0 {
-		return map[string]bool{}
-	}
-	target := make(map[string]bool, len(source))
-	for key, value := range source {
-		if !value {
-			continue
-		}
-		normalized := normalizeHeaderContextKey(key)
-		if normalized == "" {
-			continue
-		}
-		target[normalized] = true
-	}
-	return target
+	return strings.HasPrefix(key, "re:") || strings.HasPrefix(key, "regex:")
 }
 
 func GetEffectiveHeaderOverride(info *RelayInfo) map[string]interface{} {
 	if info == nil {
 		return map[string]interface{}{}
 	}
-	base := getHeaderOverrideMap(info)
-	if !info.UseRuntimeHeadersOverride {
-		return cloneHeaderOverrideMap(base)
+	if info.UseRuntimeHeadersOverride {
+		return sanitizeHeaderOverrideMap(info.RuntimeHeadersOverride)
 	}
-	return mergeHeaderOverrideSource(base, info.RuntimeHeadersOverride, cloneDeletedHeaderKeys(info.RuntimeHeadersDeletedNormalized))
+	return sanitizeHeaderOverrideMap(getHeaderOverrideMap(info))
 }
 
 func tryParseOperations(paramOverride map[string]interface{}) ([]ParamOperation, bool) {
 	// 检查是否包含 "operations" 字段
-	if opsValue, exists := paramOverride["operations"]; exists {
-		if opsSlice, ok := opsValue.([]interface{}); ok {
-			var operations []ParamOperation
-			for _, op := range opsSlice {
-				if opMap, ok := op.(map[string]interface{}); ok {
-					operation := ParamOperation{}
-
-					// 断言必要字段
-					if path, ok := opMap["path"].(string); ok {
-						operation.Path = path
-					}
-					if mode, ok := opMap["mode"].(string); ok {
-						operation.Mode = mode
-					} else {
-						return nil, false // mode 是必需的
-					}
-
-					// 可选字段
-					if value, exists := opMap["value"]; exists {
-						operation.Value = value
-					}
-					if keepOrigin, ok := opMap["keep_origin"].(bool); ok {
-						operation.KeepOrigin = keepOrigin
-					}
-					if from, ok := opMap["from"].(string); ok {
-						operation.From = from
-					}
-					if to, ok := opMap["to"].(string); ok {
-						operation.To = to
-					}
-					if logic, ok := opMap["logic"].(string); ok {
-						operation.Logic = logic
-					} else {
-						operation.Logic = "OR" // 默认为OR
-					}
-
-					// 解析条件
-					if conditions, exists := opMap["conditions"]; exists {
-						parsedConditions, err := parseConditionOperations(conditions)
-						if err != nil {
-							return nil, false
-						}
-						operation.Conditions = append(operation.Conditions, parsedConditions...)
-					}
-
-					operations = append(operations, operation)
-				} else {
-					return nil, false
-				}
-			}
-			return operations, true
-		}
+	opsValue, exists := paramOverride["operations"]
+	if !exists {
+		return nil, false
 	}
 
-	return nil, false
+	var opMaps []map[string]interface{}
+	switch ops := opsValue.(type) {
+	case []interface{}:
+		opMaps = make([]map[string]interface{}, 0, len(ops))
+		for _, op := range ops {
+			opMap, ok := op.(map[string]interface{})
+			if !ok {
+				return nil, false
+			}
+			opMaps = append(opMaps, opMap)
+		}
+	case []map[string]interface{}:
+		opMaps = ops
+	default:
+		return nil, false
+	}
+
+	operations := make([]ParamOperation, 0, len(opMaps))
+	for _, opMap := range opMaps {
+		operation := ParamOperation{}
+
+		// 断言必要字段
+		if path, ok := opMap["path"].(string); ok {
+			operation.Path = path
+		}
+		if mode, ok := opMap["mode"].(string); ok {
+			operation.Mode = mode
+		} else {
+			return nil, false // mode 是必需的
+		}
+
+		// 可选字段
+		if value, exists := opMap["value"]; exists {
+			operation.Value = value
+		}
+		if keepOrigin, ok := opMap["keep_origin"].(bool); ok {
+			operation.KeepOrigin = keepOrigin
+		}
+		if from, ok := opMap["from"].(string); ok {
+			operation.From = from
+		}
+		if to, ok := opMap["to"].(string); ok {
+			operation.To = to
+		}
+		if logic, ok := opMap["logic"].(string); ok {
+			operation.Logic = logic
+		} else {
+			operation.Logic = "OR" // 默认为OR
+		}
+
+		// 解析条件
+		if conditions, exists := opMap["conditions"]; exists {
+			parsedConditions, err := parseConditionOperations(conditions)
+			if err != nil {
+				return nil, false
+			}
+			operation.Conditions = append(operation.Conditions, parsedConditions...)
+		}
+
+		operations = append(operations, operation)
+	}
+	return operations, true
 }
 
 func checkConditions(jsonStr, contextJSON string, conditions []ConditionOperation, logic string) (bool, error) {
@@ -712,15 +686,10 @@ func marshalContextJSON(context map[string]interface{}) (string, error) {
 }
 
 func setHeaderOverrideInContext(context map[string]interface{}, headerName string, value interface{}, keepOrigin bool) error {
-	headerName = strings.TrimSpace(headerName)
+	headerName = normalizeHeaderContextKey(headerName)
 	if headerName == "" {
 		return fmt.Errorf("header name is required")
 	}
-	if keepOrigin {
-		if _, exists := getHeaderValueFromContext(context, headerName); exists {
-			return nil
-		}
-	}
 	if value == nil {
 		return fmt.Errorf("header value is required")
 	}
@@ -730,21 +699,21 @@ func setHeaderOverrideInContext(context map[string]interface{}, headerName strin
 	}
 
 	rawHeaders := ensureMapKeyInContext(context, paramOverrideContextHeaderOverride)
-	rawHeaders[headerName] = headerValue
-
-	normalizedHeaderName := normalizeHeaderContextKey(headerName)
-	normalizedHeaders := ensureMapKeyInContext(context, paramOverrideContextHeaderOverrideNormalized)
-	normalizedHeaders[normalizedHeaderName] = headerValue
-	if normalizedHeaderName != "" {
-		deletedHeaders := ensureMapKeyInContext(context, paramOverrideContextHeaderOverrideDeleted)
-		delete(deletedHeaders, normalizedHeaderName)
+	if keepOrigin {
+		if existing, ok := rawHeaders[headerName]; ok {
+			existingValue := strings.TrimSpace(fmt.Sprintf("%v", existing))
+			if existingValue != "" {
+				return nil
+			}
+		}
 	}
+	rawHeaders[headerName] = headerValue
 	return nil
 }
 
 func copyHeaderInContext(context map[string]interface{}, fromHeader, toHeader string, keepOrigin bool) error {
-	fromHeader = strings.TrimSpace(fromHeader)
-	toHeader = strings.TrimSpace(toHeader)
+	fromHeader = normalizeHeaderContextKey(fromHeader)
+	toHeader = normalizeHeaderContextKey(toHeader)
 	if fromHeader == "" || toHeader == "" {
 		return fmt.Errorf("copy_header from/to is required")
 	}
@@ -756,8 +725,8 @@ func copyHeaderInContext(context map[string]interface{}, fromHeader, toHeader st
 }
 
 func moveHeaderInContext(context map[string]interface{}, fromHeader, toHeader string, keepOrigin bool) error {
-	fromHeader = strings.TrimSpace(fromHeader)
-	toHeader = strings.TrimSpace(toHeader)
+	fromHeader = normalizeHeaderContextKey(fromHeader)
+	toHeader = normalizeHeaderContextKey(toHeader)
 	if fromHeader == "" || toHeader == "" {
 		return fmt.Errorf("move_header from/to is required")
 	}
@@ -771,31 +740,19 @@ func moveHeaderInContext(context map[string]interface{}, fromHeader, toHeader st
 }
 
 func deleteHeaderOverrideInContext(context map[string]interface{}, headerName string) error {
-	headerName = strings.TrimSpace(headerName)
+	headerName = normalizeHeaderContextKey(headerName)
 	if headerName == "" {
 		return fmt.Errorf("header name is required")
 	}
 	rawHeaders := ensureMapKeyInContext(context, paramOverrideContextHeaderOverride)
-	for key := range rawHeaders {
-		if strings.EqualFold(strings.TrimSpace(key), headerName) {
-			delete(rawHeaders, key)
-		}
-	}
-
-	normalizedHeaders := ensureMapKeyInContext(context, paramOverrideContextHeaderOverrideNormalized)
-	normalizedHeaderName := normalizeHeaderContextKey(headerName)
-	delete(normalizedHeaders, normalizedHeaderName)
-	if normalizedHeaderName != "" {
-		deletedHeaders := ensureMapKeyInContext(context, paramOverrideContextHeaderOverrideDeleted)
-		deletedHeaders[normalizedHeaderName] = true
-	}
+	delete(rawHeaders, headerName)
 	return nil
 }
 
 func parseHeaderPassThroughNames(value interface{}) ([]string, error) {
 	normalizeNames := func(values []string) []string {
 		names := lo.FilterMap(values, func(item string, _ int) (string, bool) {
-			headerName := strings.TrimSpace(item)
+			headerName := normalizeHeaderContextKey(item)
 			if headerName == "" {
 				return "", false
 			}
@@ -825,7 +782,20 @@ func parseHeaderPassThroughNames(value interface{}) ([]string, error) {
 		return names, nil
 	case []interface{}:
 		names := lo.FilterMap(raw, func(item interface{}, _ int) (string, bool) {
-			headerName := strings.TrimSpace(fmt.Sprintf("%v", item))
+			headerName := normalizeHeaderContextKey(fmt.Sprintf("%v", item))
+			if headerName == "" {
+				return "", false
+			}
+			return headerName, true
+		})
+		names = lo.Uniq(names)
+		if len(names) == 0 {
+			return nil, fmt.Errorf("pass_headers value is invalid")
+		}
+		return names, nil
+	case []string:
+		names := lo.FilterMap(raw, func(item string, _ int) (string, bool) {
+			headerName := normalizeHeaderContextKey(item)
 			if headerName == "" {
 				return "", false
 			}
@@ -994,76 +964,29 @@ func ensureMapKeyInContext(context map[string]interface{}, key string) map[strin
 }
 
 func getHeaderValueFromContext(context map[string]interface{}, headerName string) (string, bool) {
-	headerName = strings.TrimSpace(headerName)
+	headerName = normalizeHeaderContextKey(headerName)
 	if headerName == "" {
 		return "", false
 	}
-	if value, ok := findHeaderValueInMap(ensureMapKeyInContext(context, paramOverrideContextHeaderOverride), headerName); ok {
-		return value, true
-	}
-	if value, ok := findHeaderValueInMap(ensureMapKeyInContext(context, paramOverrideContextRequestHeadersRaw), headerName); ok {
-		return value, true
-	}
-
-	normalizedName := normalizeHeaderContextKey(headerName)
-	if normalizedName == "" {
-		return "", false
-	}
-	if value, ok := findHeaderValueInMap(ensureMapKeyInContext(context, paramOverrideContextHeaderOverrideNormalized), normalizedName); ok {
-		return value, true
-	}
-	if value, ok := findHeaderValueInMap(ensureMapKeyInContext(context, paramOverrideContextRequestHeaders), normalizedName); ok {
-		return value, true
+	for _, key := range []string{paramOverrideContextHeaderOverride, paramOverrideContextRequestHeaders} {
+		source := ensureMapKeyInContext(context, key)
+		raw, ok := source[headerName]
+		if !ok {
+			continue
+		}
+		value := strings.TrimSpace(fmt.Sprintf("%v", raw))
+		if value != "" {
+			return value, true
+		}
 	}
 	return "", false
 }
 
-func findHeaderValueInMap(source map[string]interface{}, key string) (string, bool) {
-	if len(source) == 0 {
-		return "", false
-	}
-	entries := lo.Entries(source)
-	entry, ok := lo.Find(entries, func(item lo.Entry[string, interface{}]) bool {
-		return strings.EqualFold(strings.TrimSpace(item.Key), key)
-	})
-	if !ok {
-		return "", false
-	}
-	value := strings.TrimSpace(fmt.Sprintf("%v", entry.Value))
-	if value == "" {
-		return "", false
-	}
-	return value, true
-}
-
 func normalizeHeaderContextKey(key string) string {
-	key = strings.TrimSpace(strings.ToLower(key))
-	if key == "" {
-		return ""
-	}
-	var b strings.Builder
-	b.Grow(len(key))
-	previousUnderscore := false
-	for _, r := range key {
-		switch {
-		case r >= 'a' && r <= 'z':
-			b.WriteRune(r)
-			previousUnderscore = false
-		case r >= '0' && r <= '9':
-			b.WriteRune(r)
-			previousUnderscore = false
-		default:
-			if !previousUnderscore {
-				b.WriteByte('_')
-				previousUnderscore = true
-			}
-		}
-	}
-	result := strings.Trim(b.String(), "_")
-	return result
+	return strings.TrimSpace(strings.ToLower(key))
 }
 
-func buildNormalizedHeaders(headers map[string]string) map[string]interface{} {
+func buildRequestHeadersContext(headers map[string]string) map[string]interface{} {
 	if len(headers) == 0 {
 		return map[string]interface{}{}
 	}
@@ -1081,54 +1004,6 @@ func buildNormalizedHeaders(headers map[string]string) map[string]interface{} {
 	})
 }
 
-func buildRawHeaders(headers map[string]string) map[string]interface{} {
-	if len(headers) == 0 {
-		return map[string]interface{}{}
-	}
-	entries := lo.Entries(headers)
-	rawEntries := lo.FilterMap(entries, func(item lo.Entry[string, string], _ int) (lo.Entry[string, string], bool) {
-		key := strings.TrimSpace(item.Key)
-		value := strings.TrimSpace(item.Value)
-		if key == "" || value == "" {
-			return lo.Entry[string, string]{}, false
-		}
-		return lo.Entry[string, string]{Key: key, Value: value}, true
-	})
-	return lo.SliceToMap(rawEntries, func(item lo.Entry[string, string]) (string, interface{}) {
-		return item.Key, item.Value
-	})
-}
-
-func buildHeaderOverrideContext(headers map[string]interface{}) (map[string]interface{}, map[string]interface{}) {
-	if len(headers) == 0 {
-		return map[string]interface{}{}, map[string]interface{}{}
-	}
-	entries := lo.Entries(headers)
-	rawEntries := lo.FilterMap(entries, func(item lo.Entry[string, interface{}], _ int) (lo.Entry[string, string], bool) {
-		key := strings.TrimSpace(item.Key)
-		value := strings.TrimSpace(fmt.Sprintf("%v", item.Value))
-		if key == "" || value == "" {
-			return lo.Entry[string, string]{}, false
-		}
-		return lo.Entry[string, string]{Key: key, Value: value}, true
-	})
-
-	raw := lo.SliceToMap(rawEntries, func(item lo.Entry[string, string]) (string, interface{}) {
-		return item.Key, item.Value
-	})
-	normalizedEntries := lo.FilterMap(rawEntries, func(item lo.Entry[string, string], _ int) (lo.Entry[string, string], bool) {
-		normalized := normalizeHeaderContextKey(item.Key)
-		if normalized == "" {
-			return lo.Entry[string, string]{}, false
-		}
-		return lo.Entry[string, string]{Key: normalized, Value: item.Value}, true
-	})
-	normalized := lo.SliceToMap(normalizedEntries, func(item lo.Entry[string, string]) (string, interface{}) {
-		return item.Key, item.Value
-	})
-	return raw, normalized
-}
-
 func syncRuntimeHeaderOverrideFromContext(info *RelayInfo, context map[string]interface{}) {
 	if info == nil || context == nil {
 		return
@@ -1141,55 +1016,10 @@ func syncRuntimeHeaderOverrideFromContext(info *RelayInfo, context map[string]in
 	if !ok {
 		return
 	}
-
-	entries := lo.Entries(rawMap)
-	sanitized := lo.FilterMap(entries, func(item lo.Entry[string, interface{}], _ int) (lo.Entry[string, interface{}], bool) {
-		key := strings.TrimSpace(item.Key)
-		if key == "" {
-			return lo.Entry[string, interface{}]{}, false
-		}
-		value := strings.TrimSpace(fmt.Sprintf("%v", item.Value))
-		if value == "" {
-			return lo.Entry[string, interface{}]{}, false
-		}
-		return lo.Entry[string, interface{}]{Key: key, Value: value}, true
-	})
-	info.RuntimeHeadersOverride = lo.SliceToMap(sanitized, func(item lo.Entry[string, interface{}]) (string, interface{}) {
-		return item.Key, item.Value
-	})
-	info.RuntimeHeadersDeletedNormalized = sanitizeRuntimeDeletedHeadersFromContext(context)
+	info.RuntimeHeadersOverride = sanitizeHeaderOverrideMap(rawMap)
 	info.UseRuntimeHeadersOverride = true
 }
 
-func sanitizeRuntimeDeletedHeadersFromContext(context map[string]interface{}) map[string]bool {
-	deletedRaw, exists := context[paramOverrideContextHeaderOverrideDeleted]
-	if !exists {
-		return nil
-	}
-	deletedMap, ok := deletedRaw.(map[string]interface{})
-	if !ok || len(deletedMap) == 0 {
-		return nil
-	}
-	entries := lo.Entries(deletedMap)
-	sanitized := lo.FilterMap(entries, func(item lo.Entry[string, interface{}], _ int) (string, bool) {
-		if keep, ok := item.Value.(bool); ok && !keep {
-			return "", false
-		}
-		normalized := normalizeHeaderContextKey(item.Key)
-		if normalized == "" {
-			return "", false
-		}
-		return normalized, true
-	})
-	if len(sanitized) == 0 {
-		return nil
-	}
-	keys := lo.Uniq(sanitized)
-	return lo.SliceToMap(keys, func(item string) (string, bool) {
-		return item, true
-	})
-}
-
 func moveValue(jsonStr, fromPath, toPath string) (string, error) {
 	sourceValue := gjson.Get(jsonStr, fromPath)
 	if !sourceValue.Exists() {
@@ -1635,16 +1465,10 @@ func BuildParamOverrideContext(info *RelayInfo) map[string]interface{} {
 		}
 	}
 
-	ctx[paramOverrideContextRequestHeaders] = buildNormalizedHeaders(info.RequestHeaders)
-	ctx[paramOverrideContextRequestHeadersRaw] = buildRawHeaders(info.RequestHeaders)
+	ctx[paramOverrideContextRequestHeaders] = buildRequestHeadersContext(info.RequestHeaders)
 
 	headerOverrideSource := GetEffectiveHeaderOverride(info)
-	rawHeaderOverride, normalizedHeaderOverride := buildHeaderOverrideContext(headerOverrideSource)
-	ctx[paramOverrideContextHeaderOverride] = rawHeaderOverride
-	ctx[paramOverrideContextHeaderOverrideNormalized] = normalizedHeaderOverride
-	ctx[paramOverrideContextHeaderOverrideDeleted] = lo.SliceToMap(lo.Keys(cloneDeletedHeaderKeys(info.RuntimeHeadersDeletedNormalized)), func(item string) (string, interface{}) {
-		return item, true
-	})
+	ctx[paramOverrideContextHeaderOverride] = sanitizeHeaderOverrideMap(headerOverrideSource)
 
 	ctx["retry_index"] = info.RetryIndex
 	ctx["is_retry"] = info.RetryIndex > 0
diff --git a/relay/common/override_test.go b/relay/common/override_test.go
index a9dad7177..7a27ca407 100644
--- a/relay/common/override_test.go
+++ b/relay/common/override_test.go
@@ -1005,7 +1005,7 @@ func TestApplyParamOverrideSetHeaderAndUseInLaterCondition(t *testing.T) {
 				"value": 0.1,
 				"conditions": []interface{}{
 					map[string]interface{}{
-						"path":  "header_override_normalized.x_debug_mode",
+						"path":  "header_override.x-debug-mode",
 						"mode":  "full",
 						"value": "enabled",
 					},
@@ -1036,7 +1036,7 @@ func TestApplyParamOverrideCopyHeaderFromRequestHeaders(t *testing.T) {
 				"value": 0.1,
 				"conditions": []interface{}{
 					map[string]interface{}{
-						"path":  "header_override_normalized.x_upstream_auth",
+						"path":  "header_override.x-upstream-auth",
 						"mode":  "contains",
 						"value": "Bearer ",
 					},
@@ -1045,9 +1045,6 @@ func TestApplyParamOverrideCopyHeaderFromRequestHeaders(t *testing.T) {
 		},
 	}
 	ctx := map[string]interface{}{
-		"request_headers_raw": map[string]interface{}{
-			"Authorization": "Bearer token-123",
-		},
 		"request_headers": map[string]interface{}{
 			"authorization": "Bearer token-123",
 		},
@@ -1071,9 +1068,6 @@ func TestApplyParamOverridePassHeadersSkipsMissingHeaders(t *testing.T) {
 		},
 	}
 	ctx := map[string]interface{}{
-		"request_headers_raw": map[string]interface{}{
-			"Session_id": "sess-123",
-		},
 		"request_headers": map[string]interface{}{
 			"session_id": "sess-123",
 		},
@@ -1089,10 +1083,10 @@ func TestApplyParamOverridePassHeadersSkipsMissingHeaders(t *testing.T) {
 	if !ok {
 		t.Fatalf("expected header_override context map")
 	}
-	if headers["Session_id"] != "sess-123" {
-		t.Fatalf("expected Session_id to be passed, got: %v", headers["Session_id"])
+	if headers["session_id"] != "sess-123" {
+		t.Fatalf("expected session_id to be passed, got: %v", headers["session_id"])
 	}
-	if _, exists := headers["X-Codex-Beta-Features"]; exists {
+	if _, exists := headers["x-codex-beta-features"]; exists {
 		t.Fatalf("expected missing header to be skipped")
 	}
 }
@@ -1109,9 +1103,6 @@ func TestApplyParamOverrideCopyHeaderSkipsMissingSource(t *testing.T) {
 		},
 	}
 	ctx := map[string]interface{}{
-		"request_headers_raw": map[string]interface{}{
-			"Authorization": "Bearer token-123",
-		},
 		"request_headers": map[string]interface{}{
 			"authorization": "Bearer token-123",
 		},
@@ -1127,7 +1118,7 @@ func TestApplyParamOverrideCopyHeaderSkipsMissingSource(t *testing.T) {
 	if !ok {
 		return
 	}
-	if _, exists := headers["X-Upstream-Auth"]; exists {
+	if _, exists := headers["x-upstream-auth"]; exists {
 		t.Fatalf("expected X-Upstream-Auth to be skipped when source header is missing")
 	}
 }
@@ -1144,9 +1135,6 @@ func TestApplyParamOverrideMoveHeaderSkipsMissingSource(t *testing.T) {
 		},
 	}
 	ctx := map[string]interface{}{
-		"request_headers_raw": map[string]interface{}{
-			"Authorization": "Bearer token-123",
-		},
 		"request_headers": map[string]interface{}{
 			"authorization": "Bearer token-123",
 		},
@@ -1162,7 +1150,7 @@ func TestApplyParamOverrideMoveHeaderSkipsMissingSource(t *testing.T) {
 	if !ok {
 		return
 	}
-	if _, exists := headers["X-Upstream-Auth"]; exists {
+	if _, exists := headers["x-upstream-auth"]; exists {
 		t.Fatalf("expected X-Upstream-Auth to be skipped when source header is missing")
 	}
 }
@@ -1179,9 +1167,6 @@ func TestApplyParamOverrideSyncFieldsHeaderToJSON(t *testing.T) {
 		},
 	}
 	ctx := map[string]interface{}{
-		"request_headers_raw": map[string]interface{}{
-			"session_id": "sess-123",
-		},
 		"request_headers": map[string]interface{}{
 			"session_id": "sess-123",
 		},
@@ -1234,9 +1219,6 @@ func TestApplyParamOverrideSyncFieldsNoChangeWhenBothExist(t *testing.T) {
 		},
 	}
 	ctx := map[string]interface{}{
-		"request_headers_raw": map[string]interface{}{
-			"session_id": "cache-header",
-		},
 		"request_headers": map[string]interface{}{
 			"session_id": "cache-header",
 		},
@@ -1288,10 +1270,7 @@ func TestApplyParamOverrideSetHeaderKeepOrigin(t *testing.T) {
 	}
 	ctx := map[string]interface{}{
 		"header_override": map[string]interface{}{
-			"X-Feature-Flag": "legacy-value",
-		},
-		"header_override_normalized": map[string]interface{}{
-			"x_feature_flag": "legacy-value",
+			"x-feature-flag": "legacy-value",
 		},
 	}
 
@@ -1303,8 +1282,8 @@ func TestApplyParamOverrideSetHeaderKeepOrigin(t *testing.T) {
 	if !ok {
 		t.Fatalf("expected header_override context map")
 	}
-	if headers["X-Feature-Flag"] != "legacy-value" {
-		t.Fatalf("expected keep_origin to preserve old value, got: %v", headers["X-Feature-Flag"])
+	if headers["x-feature-flag"] != "legacy-value" {
+		t.Fatalf("expected keep_origin to preserve old value, got: %v", headers["x-feature-flag"])
 	}
 }
 
@@ -1371,14 +1350,14 @@ func TestApplyParamOverrideWithRelayInfoSyncRuntimeHeaders(t *testing.T) {
 	if !info.UseRuntimeHeadersOverride {
 		t.Fatalf("expected runtime header override to be enabled")
 	}
-	if info.RuntimeHeadersOverride["X-Keep-Me"] != "keep" {
-		t.Fatalf("expected X-Keep-Me header to be preserved, got: %v", info.RuntimeHeadersOverride["X-Keep-Me"])
+	if info.RuntimeHeadersOverride["x-keep-me"] != "keep" {
+		t.Fatalf("expected x-keep-me header to be preserved, got: %v", info.RuntimeHeadersOverride["x-keep-me"])
 	}
-	if info.RuntimeHeadersOverride["X-Injected-By-Param-Override"] != "enabled" {
-		t.Fatalf("expected X-Injected-By-Param-Override header to be set, got: %v", info.RuntimeHeadersOverride["X-Injected-By-Param-Override"])
+	if info.RuntimeHeadersOverride["x-injected-by-param-override"] != "enabled" {
+		t.Fatalf("expected x-injected-by-param-override header to be set, got: %v", info.RuntimeHeadersOverride["x-injected-by-param-override"])
 	}
-	if _, exists := info.RuntimeHeadersOverride["X-Delete-Me"]; exists {
-		t.Fatalf("expected X-Delete-Me header to be deleted")
+	if _, exists := info.RuntimeHeadersOverride["x-delete-me"]; exists {
+		t.Fatalf("expected x-delete-me header to be deleted")
 	}
 }
 
@@ -1410,25 +1389,22 @@ func TestApplyParamOverrideWithRelayInfoMoveAndCopyHeaders(t *testing.T) {
 	if err != nil {
 		t.Fatalf("ApplyParamOverrideWithRelayInfo returned error: %v", err)
 	}
-	if _, exists := info.RuntimeHeadersOverride["X-Legacy-Trace"]; exists {
+	if _, exists := info.RuntimeHeadersOverride["x-legacy-trace"]; exists {
 		t.Fatalf("expected source header to be removed after move")
 	}
-	if info.RuntimeHeadersOverride["X-Trace"] != "trace-123" {
-		t.Fatalf("expected X-Trace to be set, got: %v", info.RuntimeHeadersOverride["X-Trace"])
+	if info.RuntimeHeadersOverride["x-trace"] != "trace-123" {
+		t.Fatalf("expected x-trace to be set, got: %v", info.RuntimeHeadersOverride["x-trace"])
 	}
-	if info.RuntimeHeadersOverride["X-Trace-Backup"] != "trace-123" {
-		t.Fatalf("expected X-Trace-Backup to be copied, got: %v", info.RuntimeHeadersOverride["X-Trace-Backup"])
+	if info.RuntimeHeadersOverride["x-trace-backup"] != "trace-123" {
+		t.Fatalf("expected x-trace-backup to be copied, got: %v", info.RuntimeHeadersOverride["x-trace-backup"])
 	}
 }
 
-func TestGetEffectiveHeaderOverrideMergesRuntimeAndChannelOverrides(t *testing.T) {
+func TestGetEffectiveHeaderOverrideUsesRuntimeOverrideAsFinalResult(t *testing.T) {
 	info := &RelayInfo{
 		UseRuntimeHeadersOverride: true,
 		RuntimeHeadersOverride: map[string]interface{}{
-			"X-Runtime": "runtime-only",
-		},
-		RuntimeHeadersDeletedNormalized: map[string]bool{
-			"x-deleted": true,
+			"x-runtime": "runtime-only",
 		},
 		ChannelMeta: &ChannelMeta{
 			HeadersOverride: map[string]interface{}{
@@ -1439,14 +1415,11 @@ func TestGetEffectiveHeaderOverrideMergesRuntimeAndChannelOverrides(t *testing.T
 	}
 
 	effective := GetEffectiveHeaderOverride(info)
-	if effective["X-Static"] != "static-value" {
-		t.Fatalf("expected X-Static from channel override, got: %v", effective["X-Static"])
+	if effective["x-runtime"] != "runtime-only" {
+		t.Fatalf("expected x-runtime from runtime override, got: %v", effective["x-runtime"])
 	}
-	if effective["X-Runtime"] != "runtime-only" {
-		t.Fatalf("expected X-Runtime from runtime override, got: %v", effective["X-Runtime"])
-	}
-	if _, exists := effective["X-Deleted"]; exists {
-		t.Fatalf("expected deleted headers to stay deleted in effective override")
+	if _, exists := effective["x-static"]; exists {
+		t.Fatalf("expected runtime override to be final and not merge channel headers")
 	}
 }
 
diff --git a/relay/common/relay_info.go b/relay/common/relay_info.go
index 946294d49..8b0789c0d 100644
--- a/relay/common/relay_info.go
+++ b/relay/common/relay_info.go
@@ -148,7 +148,6 @@ type RelayInfo struct {
 	RetryIndex                            int
 	LastError                             *types.NewAPIError
 	RuntimeHeadersOverride                map[string]interface{}
-	RuntimeHeadersDeletedNormalized       map[string]bool
 	UseRuntimeHeadersOverride             bool
 
 	PriceData types.PriceData
diff --git a/service/channel_affinity_template_test.go b/service/channel_affinity_template_test.go
index 71e29d668..acf301543 100644
--- a/service/channel_affinity_template_test.go
+++ b/service/channel_affinity_template_test.go
@@ -1,9 +1,15 @@
 package service
 
 import (
+	"fmt"
+	"net/http"
 	"net/http/httptest"
+	"strings"
 	"testing"
+	"time"
 
+	relaycommon "github.com/QuantumNous/new-api/relay/common"
+	"github.com/QuantumNous/new-api/setting/operation_setting"
 	"github.com/gin-gonic/gin"
 	"github.com/stretchr/testify/require"
 )
@@ -67,3 +73,73 @@ func TestApplyChannelAffinityOverrideTemplate_MergeTemplate(t *testing.T) {
 	require.Equal(t, "rule-with-template", overrideInfo["rule_name"])
 	require.EqualValues(t, 2, overrideInfo["param_override_keys"])
 }
+
+func TestChannelAffinityHitCodexTemplatePassHeadersEffective(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	setting := operation_setting.GetChannelAffinitySetting()
+	require.NotNil(t, setting)
+
+	var codexRule *operation_setting.ChannelAffinityRule
+	for i := range setting.Rules {
+		rule := &setting.Rules[i]
+		if strings.EqualFold(strings.TrimSpace(rule.Name), "codex cli trace") {
+			codexRule = rule
+			break
+		}
+	}
+	require.NotNil(t, codexRule)
+
+	affinityValue := fmt.Sprintf("pc-hit-%d", time.Now().UnixNano())
+	cacheKeySuffix := buildChannelAffinityCacheKeySuffix(*codexRule, "default", affinityValue)
+
+	cache := getChannelAffinityCache()
+	require.NoError(t, cache.SetWithTTL(cacheKeySuffix, 9527, time.Minute))
+	t.Cleanup(func() {
+		_, _ = cache.DeleteMany([]string{cacheKeySuffix})
+	})
+
+	rec := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(rec)
+	ctx.Request = httptest.NewRequest(http.MethodPost, "/v1/responses", strings.NewReader(fmt.Sprintf(`{"prompt_cache_key":"%s"}`, affinityValue)))
+	ctx.Request.Header.Set("Content-Type", "application/json")
+
+	channelID, found := GetPreferredChannelByAffinity(ctx, "gpt-5", "default")
+	require.True(t, found)
+	require.Equal(t, 9527, channelID)
+
+	baseOverride := map[string]interface{}{
+		"temperature": 0.2,
+	}
+	mergedOverride, applied := ApplyChannelAffinityOverrideTemplate(ctx, baseOverride)
+	require.True(t, applied)
+	require.Equal(t, 0.2, mergedOverride["temperature"])
+
+	info := &relaycommon.RelayInfo{
+		RequestHeaders: map[string]string{
+			"Originator": "Codex CLI",
+			"Session_id": "sess-123",
+			"User-Agent": "codex-cli-test",
+		},
+		ChannelMeta: &relaycommon.ChannelMeta{
+			ParamOverride: mergedOverride,
+			HeadersOverride: map[string]interface{}{
+				"X-Static": "legacy-static",
+			},
+		},
+	}
+
+	_, err := relaycommon.ApplyParamOverrideWithRelayInfo([]byte(`{"model":"gpt-5"}`), info)
+	require.NoError(t, err)
+	require.True(t, info.UseRuntimeHeadersOverride)
+
+	require.Equal(t, "legacy-static", info.RuntimeHeadersOverride["x-static"])
+	require.Equal(t, "Codex CLI", info.RuntimeHeadersOverride["originator"])
+	require.Equal(t, "sess-123", info.RuntimeHeadersOverride["session_id"])
+	require.Equal(t, "codex-cli-test", info.RuntimeHeadersOverride["user-agent"])
+
+	_, exists := info.RuntimeHeadersOverride["x-codex-beta-features"]
+	require.False(t, exists)
+	_, exists = info.RuntimeHeadersOverride["x-codex-turn-metadata"]
+	require.False(t, exists)
+}