feat(session-history): Add delete button and show sessions for all agents

- Add deleteSession method to useSessionHistory hook
- Add Delete button to all session items (always visible)
- Change early return for restoration non-supporting agents to warning banner
- Show locally saved sessions for all agents (for deletion)
- Add warning banner and delete button styles

src/components/chat/ChatView.tsx

@@ -381,6 +381,16 @@ function ChatComponent({
 						logger.error("Session fork error:", error);
 					}
 				},
+				onDeleteSession: async (sessionId: string) => {
+					try {
+						logger.log(`[ChatView] Deleting session: ${sessionId}`);
+						await sessionHistory.deleteSession(sessionId);
+						new Notice("[Agent Client] Session deleted");
+					} catch (error) {
+						new Notice("[Agent Client] Failed to delete session");
+						logger.error("Session delete error:", error);
+					}
+				},
 				onLoadMore: () => {
 					void sessionHistory.loadMoreSessions();
 				},
@@ -452,6 +462,16 @@ function ChatComponent({
 						logger.error("Session fork error:", error);
 					}
 				},
+				onDeleteSession: async (sessionId: string) => {
+					try {
+						logger.log(`[ChatView] Deleting session: ${sessionId}`);
+						await sessionHistory.deleteSession(sessionId);
+						new Notice("[Agent Client] Session deleted");
+					} catch (error) {
+						new Notice("[Agent Client] Failed to delete session");
+						logger.error("Session delete error:", error);
+					}
+				},
 				onLoadMore: () => {
 					void sessionHistory.loadMoreSessions();
 				},

src/components/chat/SessionHistoryContent.tsx

@@ -43,6 +43,8 @@ export interface SessionHistoryContentProps {
 	onResumeSession: (sessionId: string, cwd: string) => Promise<void>;
 	/** Callback when a session is forked (create new branch) */
 	onForkSession: (sessionId: string, cwd: string) => Promise<void>;
+	/** Callback when a session is deleted */
+	onDeleteSession: (sessionId: string) => Promise<void>;
 	/** Callback to load more sessions (pagination) */
 	onLoadMore: () => void;
 	/** Callback to fetch sessions with filter */
@@ -229,6 +231,7 @@ function SessionItem({
 	onLoadSession,
 	onResumeSession,
 	onForkSession,
+	onDeleteSession,
 	onClose,
 }: {
 	session: SessionInfo;
@@ -238,6 +241,7 @@ function SessionItem({
 	onLoadSession: (sessionId: string, cwd: string) => Promise<void>;
 	onResumeSession: (sessionId: string, cwd: string) => Promise<void>;
 	onForkSession: (sessionId: string, cwd: string) => Promise<void>;
+	onDeleteSession: (sessionId: string) => Promise<void>;
 	onClose: () => void;
 }) {
 	const handleLoad = useCallback(() => {
@@ -255,6 +259,10 @@ function SessionItem({
 		void onForkSession(session.sessionId, session.cwd);
 	}, [session, onForkSession, onClose]);
 
+	const handleDelete = useCallback(() => {
+		void onDeleteSession(session.sessionId);
+	}, [session.sessionId, onDeleteSession]);
+
 	return (
 		<div className="agent-client-session-history-item">
 			<div className="agent-client-session-history-item-content">
@@ -297,6 +305,12 @@ function SessionItem({
 						onClick={handleFork}
 					/>
 				)}
+				<IconButton
+					iconName="trash-2"
+					label="Delete session"
+					className="agent-client-session-history-action-icon agent-client-session-history-delete-icon"
+					onClick={handleDelete}
+				/>
 			</div>
 		</div>
 	);
@@ -328,6 +342,7 @@ export function SessionHistoryContent({
 	onLoadSession,
 	onResumeSession,
 	onForkSession,
+	onDeleteSession,
 	onLoadMore,
 	onFetchSessions,
 	onClose,
@@ -361,18 +376,11 @@ export function SessionHistoryContent({
 	// Check if any session operation is available
 	const canPerformAnyOperation = canLoad || canResume || canFork;
 
-	// Show message if no session operations are supported
-	if (!canPerformAnyOperation && !debugMode) {
-		return (
-			<div className="agent-client-session-history-empty">
-				<p className="agent-client-session-history-empty-text">
-					This agent does not support session restoration.
-				</p>
-			</div>
-		);
-	}
-
-	const canShowList = canList || isUsingLocalSessions;
+	// Show local sessions list (always show for delete functionality)
+	// - If agent supports list: use agent's session/list
+	// - If agent doesn't support list OR doesn't support restoration: use locally saved sessions
+	const canShowList =
+		canList || isUsingLocalSessions || !canPerformAnyOperation;
 
 	return (
 		<>
@@ -387,13 +395,21 @@ export function SessionHistoryContent({
 				/>
 			)}
 
+			{/* Warning banner for agents that don't support restoration */}
+			{!canPerformAnyOperation && (
+				<div className="agent-client-session-history-warning-banner">
+					<p>
+						This agent does not support session restoration.
+						Messages are saved locally but cannot be restored to the
+						agent.
+					</p>
+				</div>
+			)}
+
 			{/* Local sessions banner */}
-			{isUsingLocalSessions && (
+			{(isUsingLocalSessions || !canPerformAnyOperation) && (
 				<div className="agent-client-session-history-local-banner">
-					<span>
-						Locally saved sessions (agent doesn't support
-						session/list)
-					</span>
+					<span>Locally saved sessions</span>
 				</div>
 			)}
 
@@ -470,6 +486,7 @@ export function SessionHistoryContent({
 									onLoadSession={onLoadSession}
 									onResumeSession={onResumeSession}
 									onForkSession={onForkSession}
+									onDeleteSession={onDeleteSession}
 									onClose={onClose}
 								/>
 							))}

src/hooks/useSessionHistory.ts

@@ -132,6 +132,12 @@ export interface UseSessionHistoryReturn {
 	 */
 	forkSession: (sessionId: string, cwd: string) => Promise<void>;
 
+	/**
+	 * Delete a session (local metadata + message file).
+	 * @param sessionId - Session to delete
+	 */
+	deleteSession: (sessionId: string) => Promise<void>;
+
 	/**
 	 * Invalidate the session cache.
 	 * Call this when creating a new session to refresh the list.
@@ -220,15 +226,25 @@ export function useSessionHistory(
 		cacheRef.current = null;
 	}, []);
 
+	// Check if any restoration operation is available
+	const canPerformAnyOperation =
+		capabilities.canLoad || capabilities.canResume || capabilities.canFork;
+
 	/**
 	 * Fetch sessions list from agent or local storage.
 	 * Uses agent's session/list if supported, otherwise falls back to local storage.
+	 * For agents that don't support restoration, local sessions are used for deletion.
 	 * Replaces existing sessions in state.
 	 */
 	const fetchSessions = useCallback(
 		async (cwd?: string) => {
-			// If agent doesn't support list, use local sessions
-			if (!capabilities.canList) {
+			// Use local sessions if:
+			// - Agent doesn't support session/list, OR
+			// - Agent doesn't support any restoration operation (for delete only)
+			const shouldUseLocalSessions =
+				!capabilities.canList || !canPerformAnyOperation;
+
+			if (shouldUseLocalSessions) {
 				// Get locally saved sessions for this agent
 				const localSessions = settingsAccess.getSavedSessions(
 					session.agentId,
@@ -289,6 +305,7 @@ export function useSessionHistory(
 		[
 			agentClient,
 			capabilities.canList,
+			canPerformAnyOperation,
 			isCacheValid,
 			settingsAccess,
 			session.agentId,
@@ -450,6 +467,33 @@ export function useSessionHistory(
 		],
 	);
 
+	/**
+	 * Delete a session (local metadata + message file).
+	 * Removes from both local state and persistent storage.
+	 */
+	const deleteSession = useCallback(
+		async (sessionId: string) => {
+			try {
+				// Delete from persistent storage (metadata + message file)
+				await settingsAccess.deleteSession(sessionId);
+
+				// Remove from local state
+				setSessions((prev) =>
+					prev.filter((s) => s.sessionId !== sessionId),
+				);
+
+				// Invalidate cache to ensure consistency
+				invalidateCache();
+			} catch (err) {
+				const errorMessage =
+					err instanceof Error ? err.message : String(err);
+				setError(`Failed to delete session: ${errorMessage}`);
+				throw err; // Re-throw to allow caller to handle
+			}
+		},
+		[settingsAccess, invalidateCache],
+	);
+
 	return {
 		sessions,
 		loading,
@@ -475,6 +519,7 @@ export function useSessionHistory(
 		loadSession,
 		resumeSession,
 		forkSession,
+		deleteSession,
 		invalidateCache,
 	};
 }

styles.css

@@ -1519,3 +1519,27 @@ If your plugin does not need CSS, delete this file.
 	color: var(--text-muted);
 	border-left: 3px solid var(--interactive-accent);
 }
+
+/* Warning banner for agents that don't support restoration */
+.agent-client-session-history-warning-banner {
+	padding: 8px 12px;
+	margin-bottom: 12px;
+	background: var(--background-secondary);
+	border-radius: 4px;
+	border-left: 3px solid var(--text-warning);
+}
+
+.agent-client-session-history-warning-banner p {
+	margin: 0;
+	color: var(--text-muted);
+	font-size: 12px;
+}
+
+/* Delete button */
+.agent-client-session-history-delete-icon {
+	color: var(--text-muted);
+}
+
+.agent-client-session-history-delete-icon:hover {
+	color: var(--text-error);
+}