diff --git a/apps/server/src/schema.sql b/apps/server/src/schema.sql
index 66ca449..ef62af4 100644
--- a/apps/server/src/schema.sql
+++ b/apps/server/src/schema.sql
@@ -56,4 +56,4 @@ CREATE TABLE IF NOT EXISTS session_panes (
   created_at   TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp(),
   UNIQUE (session_id, position)
 );
-CREATE INDEX IF NOT EXISTS session_panes_session_idx ON session_panes (session_id);
+CREATE INDEX IF NOT EXISTS idx_session_panes_session ON session_panes (session_id);
diff --git a/apps/server/src/types/api.ts b/apps/server/src/types/api.ts
index 73068db..6ce6d80 100644
--- a/apps/server/src/types/api.ts
+++ b/apps/server/src/types/api.ts
@@ -91,15 +91,18 @@ export type ChatPaneState = Record<string, never>;
 
 export type PaneState = ChatPaneState | FileBrowserPaneState;
 
-export interface Pane {
+interface PaneBase {
   id: string;
   session_id: string;
   position: number;
-  kind: PaneKind;
-  state: PaneState;
   created_at: string;
 }
 
+export type Pane = PaneBase & (
+  | { kind: 'chat'; state: ChatPaneState }
+  | { kind: 'file_browser'; state: FileBrowserPaneState }
+);
+
 export interface PaneCreateRequest {
   kind: PaneKind;
   position?: number;  // optional; if omitted, append at end