feat: add group field to SchemaField for grouped display in Android UI

Propagate enclosing struct label tags as a group field on leaf
SchemaFields so the Android Detail screen can render group headers
with dividers (e.g. "WhatsApp", "Discord" under channels).
Suppress redundant single-group headers (e.g. agents/Defaults).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

android/backend/config/src/main/java/io/clawdroid/backend/config/ConfigApiClient.kt

@@ -31,6 +31,7 @@ data class SchemaSection(val key: String, val label: String, val fields: List<Sc
 data class SchemaField(
     val key: String,
     val label: String,
+    val group: String = "",
     val type: String,
     val secret: Boolean = false,
     val default: JsonElement = Json.parseToJsonElement("null"),

android/backend/config/src/main/java/io/clawdroid/backend/config/ConfigSectionDetailScreen.kt

@@ -9,8 +9,10 @@ import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.rememberScrollState
@@ -22,6 +24,7 @@ import androidx.compose.material3.Button
 import androidx.compose.material3.ButtonDefaults
 import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
@@ -150,7 +153,21 @@ fun ConfigSectionDetailScreen(
                         .verticalScroll(rememberScrollState()),
                     verticalArrangement = Arrangement.spacedBy(16.dp),
                 ) {
+                    var lastGroup: String? = null
                     detail.fields.forEach { field ->
+                        if (field.group != lastGroup) {
+                            lastGroup = field.group
+                            if (field.group.isNotEmpty()) {
+                                Spacer(modifier = Modifier.height(8.dp))
+                                HorizontalDivider(color = GlassBorder)
+                                Text(
+                                    text = field.group,
+                                    style = MaterialTheme.typography.titleSmall,
+                                    color = NeonCyan,
+                                    modifier = Modifier.padding(top = 8.dp),
+                                )
+                            }
+                        }
                         ConfigField(
                             field = field,
                             onValueChanged = { viewModel.onFieldValueChanged(field.key, it) },

android/backend/config/src/main/java/io/clawdroid/backend/config/ConfigUiState.kt

@@ -23,6 +23,7 @@ data class SectionSummary(val key: String, val label: String, val fieldCount: In
 data class FieldState(
     val key: String,
     val label: String,
+    val group: String = "",
     val type: String,
     val secret: Boolean,
     val value: String,

android/backend/config/src/main/java/io/clawdroid/backend/config/ConfigViewModel.kt

@@ -60,6 +60,7 @@ class ConfigViewModel(private val apiClient: ConfigApiClient) : ViewModel() {
             FieldState(
                 key = field.key,
                 label = field.label,
+                group = field.group,
                 type = field.type,
                 secret = field.secret,
                 value = display,

pkg/gateway/schema.go

@@ -11,6 +11,7 @@ import (
 type SchemaField struct {
 	Key      string      `json:"key"`
 	Label    string      `json:"label"`
+	Group    string      `json:"group,omitempty"`
 	Type     string      `json:"type"`
 	Secret   bool        `json:"secret"`
 	Default  interface{} `json:"default"`
@@ -70,7 +71,21 @@ func BuildSchema(defaultCfg *config.Config) SchemaResponse {
 		}
 
 		fieldVal := cfgVal.Field(i)
-		section.Fields = buildFields(field.Type, fieldVal, "")
+		section.Fields = buildFields(field.Type, fieldVal, "", "")
+
+		// If every field shares the same single group, the header is redundant — clear it.
+		groups := map[string]bool{}
+		for _, f := range section.Fields {
+			if f.Group != "" {
+				groups[f.Group] = true
+			}
+		}
+		if len(groups) <= 1 {
+			for j := range section.Fields {
+				section.Fields[j].Group = ""
+			}
+		}
+
 		sections = append(sections, section)
 	}
 
@@ -78,8 +93,9 @@ func BuildSchema(defaultCfg *config.Config) SchemaResponse {
 }
 
 // buildFields recursively collects fields from a struct type, flattening nested structs
-// with dot-separated key prefixes.
+// with dot-separated key prefixes. The group parameter propagates the label of the
-func buildFields(t reflect.Type, v reflect.Value, prefix string) []SchemaField {
+// enclosing struct so that leaf fields can be grouped under a header in the UI.
+func buildFields(t reflect.Type, v reflect.Value, prefix string, group string) []SchemaField {
 	var fields []SchemaField
 
 	if t.Kind() == reflect.Ptr {
@@ -122,8 +138,13 @@ func buildFields(t reflect.Type, v reflect.Value, prefix string) []SchemaField {
 
 		schemaType := goTypeToSchema(ft)
 		if schemaType == "object" {
-			// Nested struct: recurse and flatten
+			// Nested struct: recurse and flatten.
-			fields = append(fields, buildFields(ft, fieldVal, fullKey)...)
+			// Use the nested struct's label tag as group; fall back to current group.
+			childGroup := labelTag(sf)
+			if childGroup == "" {
+				childGroup = group
+			}
+			fields = append(fields, buildFields(ft, fieldVal, fullKey, childGroup)...)
 			continue
 		}
 
@@ -140,6 +161,7 @@ func buildFields(t reflect.Type, v reflect.Value, prefix string) []SchemaField {
 		fields = append(fields, SchemaField{
 			Key:     fullKey,
 			Label:   labelTag(sf),
+			Group:   group,
 			Type:    schemaType,
 			Secret:  secretKeys[jk],
 			Default: defVal,

pkg/gateway/server_test.go

@@ -2435,3 +2435,51 @@ func lastDot(s string) int {
 	}
 	return -1
 }
+
+func TestBuildSchema_FieldGroups(t *testing.T) {
+	schema := BuildSchema(config.DefaultConfig())
+
+	// Build a map from "section.fieldKey" → group
+	fieldGroup := map[string]string{}
+	for _, sec := range schema.Sections {
+		for _, f := range sec.Fields {
+			fieldGroup[sec.Key+"."+f.Key] = f.Group
+		}
+	}
+
+	tests := []struct {
+		fullKey   string
+		wantGroup string
+	}{
+		// channels: each sub-struct label becomes group
+		{"channels.whatsapp.enabled", "WhatsApp"},
+		{"channels.discord.token", "Discord"},
+		{"channels.line.channel_secret", "LINE"},
+		{"channels.telegram.token", "Telegram"},
+		{"channels.slack.bot_token", "Slack"},
+		{"channels.websocket.enabled", "WebSocket"},
+		// tools: deeper nesting uses the innermost struct label
+		{"tools.web.brave.api_key", "Brave Search"},
+		{"tools.web.brave.enabled", "Brave Search"},
+		{"tools.web.duckduckgo.enabled", "DuckDuckGo"},
+		{"tools.exec.enabled", "Shell Exec"},
+		{"tools.android.enabled", "Android"},
+		{"tools.memory.enabled", "Memory"},
+		// llm: flat fields have no group
+		{"llm.model", ""},
+		{"llm.api_key", ""},
+		// agents: single intermediate struct — group suppressed
+		{"agents.defaults.max_tokens", ""},
+	}
+
+	for _, tt := range tests {
+		got, ok := fieldGroup[tt.fullKey]
+		if !ok {
+			t.Errorf("field %q not found in schema", tt.fullKey)
+			continue
+		}
+		if got != tt.wantGroup {
+			t.Errorf("field %q group = %q, want %q", tt.fullKey, got, tt.wantGroup)
+		}
+	}
+}