session persistence: /save, /resume, cwd-scoped /sessions

- Add CWD field to PersistedSession for per-directory filtering
- /sessions now shows only sessions matching current cwd (-a for all)
- /save <name> creates a named checkpoint
- /resume <id> restores a saved session (messages + task state)
- Autosave (already existed) now persists cwd with each save

pkg/agent/commands.go

@@ -342,11 +342,13 @@ func (s *agent) handleCommand(ctx context.Context, input string) bool {
 		},
 
 		"/sessions": func(args []string) {
+			allFlag := len(args) > 0 && args[0] == "-a"
 			entries, err := os.ReadDir(s.sessionsDir)
 			if err != nil {
 				s.emit(infoEvent(fmt.Sprintf("sessions: %v", err)))
 				return
 			}
+			cwd := s.CWD()
 			found := false
 			for i := len(entries) - 1; i >= 0; i-- {
 				e := entries[i]
@@ -354,35 +356,85 @@ func (s *agent) handleCommand(ctx context.Context, input string) bool {
 					continue
 				}
 				id := strings.TrimSuffix(e.Name(), ".json")
+				data, readErr := os.ReadFile(s.sessionsDir + "/" + e.Name())
+				if readErr != nil {
+					continue
+				}
+				var ps PersistedSession
+				if json.Unmarshal(data, &ps) != nil {
+					continue
+				}
+				if !allFlag && ps.CWD != "" && ps.CWD != cwd {
+					continue
+				}
 				marker := "  "
 				if id == s.sessionID {
 					marker = "* "
 				}
-				label := id
-				if data, readErr := os.ReadFile(s.sessionsDir + "/" + e.Name()); readErr == nil {
-					var ps PersistedSession
-					if json.Unmarshal(data, &ps) == nil {
-						goal := ""
-						for _, msg := range ps.Messages {
-							if msg.Role == "user" {
-								goal = msg.Content
-								break
-							}
-						}
-						if len(goal) > 60 {
-							goal = goal[:60] + "..."
-						}
-						label = fmt.Sprintf("%-24s  [%s] %q", id, ps.Agent, goal)
+				goal := ""
+				for _, msg := range ps.Messages {
+					if msg.Role == "user" {
+						goal = msg.Content
+						break
 					}
 				}
-				s.emit(infoEvent(marker + label))
+				if len(goal) > 60 {
+					goal = goal[:60] + "..."
+				}
+				s.emit(infoEvent(marker + fmt.Sprintf("%-24s  [%s] %q", id, ps.Agent, goal)))
 				found = true
 			}
 			if !found {
-				s.emit(infoEvent("no sessions found in " + s.sessionsDir))
+				s.emit(infoEvent("no sessions for " + cwd))
 			}
 		},
 
+		"/save": func(args []string) {
+			if s.session == nil {
+				s.emit(infoEvent("error: no active session"))
+				return
+			}
+			if len(args) == 0 {
+				s.emit(infoEvent("error: /save requires a name"))
+				return
+			}
+			name := args[0]
+			path := s.sessionsDir + "/" + name + ".json"
+			if err := s.session.saveTo(path, name, s.agentName, s.CWD()); err != nil {
+				s.emit(infoEvent("error: " + err.Error()))
+				return
+			}
+			s.emit(infoEvent("saved: " + path))
+		},
+
+		"/resume": func(args []string) {
+			if len(args) == 0 {
+				s.emit(infoEvent("error: /resume requires a session id or name"))
+				return
+			}
+			if s.IsRunning() {
+				s.emit(infoEvent("error: cannot resume while agent is running"))
+				return
+			}
+			name := args[0]
+			path := s.sessionsDir + "/" + name + ".json"
+			data, err := os.ReadFile(path)
+			if err != nil {
+				s.emit(infoEvent(fmt.Sprintf("error: %v", err)))
+				return
+			}
+			var ps PersistedSession
+			if err := json.Unmarshal(data, &ps); err != nil {
+				s.emit(infoEvent(fmt.Sprintf("error: %v", err)))
+				return
+			}
+			s.session = RestoreSession(ps.Messages)
+			if ps.TaskState != nil {
+				s.session.TaskState = ps.TaskState
+			}
+			s.emit(infoEvent(fmt.Sprintf("resumed session %s (%d messages)", name, len(ps.Messages))))
+		},
+
 		"/cwd": func(args []string) {
 			if len(args) == 0 {
 				s.emit(infoEvent("cwd: " + s.CWD()))
@@ -407,7 +459,9 @@ func (s *agent) handleCommand(ctx context.Context, input string) bool {
 			lines := []string{
 				"Available commands:",
 				"  /agents          - list available agent configs",
-				"  /sessions        - list saved sessions",
+				"  /sessions [-a]   - list saved sessions (current cwd; -a for all)",
+				"  /save <name>     - save session as a named checkpoint",
+				"  /resume <id>     - resume a saved session",
 				"  /agent [name]    - show or switch active agent",
 				"  /backend [type]  - show current backend, or switch to <type>",
 				"  /model [name]    - show current model, or switch to <name>",

pkg/agent/core.go

@@ -682,7 +682,7 @@ func (s *agent) saveSession() {
 		return
 	}
 	path := s.sessionsDir + "/" + s.sessionID + ".json"
-	if err := s.session.saveTo(path, s.sessionID, s.agentName); err != nil {
+	if err := s.session.saveTo(path, s.sessionID, s.agentName, s.CWD()); err != nil {
 		s.log.Error("session save: %v", err)
 	}
 }

pkg/agent/core_test.go

@@ -1250,7 +1250,7 @@ func TestCommand_Sessions_Empty(t *testing.T) {
 	evs := collectEvents(context.Background(), c, "/sessions")
 	found := false
 	for _, s := range byRole(evs, "info") {
-		if strings.Contains(s, "no sessions found") {
+		if strings.Contains(s, "no sessions") {
 			found = true
 		}
 	}
@@ -2106,7 +2106,7 @@ func TestRestoreSession_RoundTrip(t *testing.T) {
 	s.appendUserMessage("second message")
 	s.messages = append(s.messages, backend.Message{Role: "assistant", Content: "reply"})
 
-	if err := s.saveTo(path, "test-id", "test-agent"); err != nil {
+	if err := s.saveTo(path, "test-id", "test-agent", "/tmp/test"); err != nil {
 		t.Fatalf("saveTo: %v", err)
 	}
 

pkg/agent/session.go

@@ -37,6 +37,7 @@ Be concise. Capture what another LLM needs to seamlessly continue.`
 type PersistedSession struct {
 	ID        string            `json:"id"`
 	Agent     string            `json:"agent,omitempty"`
+	CWD       string            `json:"cwd,omitempty"`
 	Messages  []backend.Message `json:"messages"`
 	TaskState *TaskState        `json:"taskState,omitempty"`
 }
@@ -81,10 +82,11 @@ func (ts *TaskState) render() string {
 }
 
 // SaveTo writes the full message history to path as JSON.
-func (s *Session) saveTo(path, id, agentName string) error {
+func (s *Session) saveTo(path, id, agentName, cwd string) error {
 	ps := PersistedSession{
 		ID:        id,
 		Agent:     agentName,
+		CWD:       cwd,
 		Messages:  s.messages,
 		TaskState: s.TaskState,
 	}