diff --git a/cmd/picoclaw/internal/agent/helpers.go b/cmd/picoclaw/internal/agent/helpers.go
index f754abc652..a995945d2b 100644
--- a/cmd/picoclaw/internal/agent/helpers.go
+++ b/cmd/picoclaw/internal/agent/helpers.go
@@ -50,6 +50,7 @@ func agentCmd(message, sessionKey, model string, debug bool) error {
 	msgBus := bus.NewMessageBus()
 	defer msgBus.Close()
 	agentLoop := agent.NewAgentLoop(cfg, msgBus, provider)
+	defer agentLoop.Close()
 
 	// Print agent startup info (only for interactive mode)
 	startupInfo := agentLoop.GetStartupInfo()
diff --git a/cmd/picoclaw/internal/gateway/helpers.go b/cmd/picoclaw/internal/gateway/helpers.go
index 4f93b858a3..fed3d5ffbe 100644
--- a/cmd/picoclaw/internal/gateway/helpers.go
+++ b/cmd/picoclaw/internal/gateway/helpers.go
@@ -214,6 +214,7 @@ func gatewayCmd(debug bool) error {
 	cronService.Stop()
 	mediaStore.Stop()
 	agentLoop.Stop()
+	agentLoop.Close()
 	fmt.Println("✓ Gateway stopped")
 
 	return nil
diff --git a/pkg/agent/instance.go b/pkg/agent/instance.go
index 97cf0fa059..709b792034 100644
--- a/pkg/agent/instance.go
+++ b/pkg/agent/instance.go
@@ -1,6 +1,7 @@
 package agent
 
 import (
+	"context"
 	"fmt"
 	"log"
 	"os"
@@ -9,6 +10,7 @@ import (
 	"strings"
 
 	"github.com/sipeed/picoclaw/pkg/config"
+	"github.com/sipeed/picoclaw/pkg/memory"
 	"github.com/sipeed/picoclaw/pkg/providers"
 	"github.com/sipeed/picoclaw/pkg/routing"
 	"github.com/sipeed/picoclaw/pkg/session"
@@ -31,7 +33,7 @@ type AgentInstance struct {
 	SummarizeMessageThreshold int
 	SummarizeTokenPercent     int
 	Provider                  providers.LLMProvider
-	Sessions                  *session.SessionManager
+	Sessions                  session.SessionStore
 	ContextBuilder            *ContextBuilder
 	Tools                     *tools.ToolRegistry
 	Subagents                 *config.SubagentsConfig
@@ -94,7 +96,7 @@ func NewAgentInstance(
 	}
 
 	sessionsDir := filepath.Join(workspace, "sessions")
-	sessionsManager := session.NewSessionManager(sessionsDir)
+	sessions := initSessionStore(sessionsDir)
 
 	contextBuilder := NewContextBuilder(workspace)
 
@@ -221,7 +223,7 @@ func NewAgentInstance(
 		SummarizeMessageThreshold: summarizeMessageThreshold,
 		SummarizeTokenPercent:     summarizeTokenPercent,
 		Provider:                  provider,
-		Sessions:                  sessionsManager,
+		Sessions:                  sessions,
 		ContextBuilder:            contextBuilder,
 		Tools:                     toolsRegistry,
 		Subagents:                 subagents,
@@ -275,6 +277,39 @@ func compilePatterns(patterns []string) []*regexp.Regexp {
 	return compiled
 }
 
+// Close releases resources held by the agent's session store.
+func (a *AgentInstance) Close() error {
+	if a.Sessions != nil {
+		return a.Sessions.Close()
+	}
+	return nil
+}
+
+// initSessionStore creates the session persistence backend.
+// It uses the JSONL store by default and auto-migrates legacy JSON sessions.
+// Falls back to SessionManager if the JSONL store cannot be initialized or
+// if migration fails (which indicates the store cannot write reliably).
+func initSessionStore(dir string) session.SessionStore {
+	store, err := memory.NewJSONLStore(dir)
+	if err != nil {
+		log.Printf("memory: init store: %v; using json sessions", err)
+		return session.NewSessionManager(dir)
+	}
+
+	if n, merr := memory.MigrateFromJSON(context.Background(), dir, store); merr != nil {
+		// Migration failure means the store could not write data.
+		// Fall back to SessionManager to avoid a split state where
+		// some sessions are in JSONL and others remain in JSON.
+		log.Printf("memory: migration failed: %v; falling back to json sessions", merr)
+		store.Close()
+		return session.NewSessionManager(dir)
+	} else if n > 0 {
+		log.Printf("memory: migrated %d session(s) to jsonl", n)
+	}
+
+	return session.NewJSONLBackend(store)
+}
+
 func expandHome(path string) string {
 	if path == "" {
 		return path
diff --git a/pkg/agent/loop.go b/pkg/agent/loop.go
index 3d13071c01..fb7806f2cc 100644
--- a/pkg/agent/loop.go
+++ b/pkg/agent/loop.go
@@ -380,6 +380,11 @@ func (al *AgentLoop) Stop() {
 	al.running.Store(false)
 }
 
+// Close releases resources held by agent session stores. Call after Stop.
+func (al *AgentLoop) Close() {
+	al.registry.Close()
+}
+
 func (al *AgentLoop) RegisterTool(tool tools.Tool) {
 	for _, agentID := range al.registry.ListAgentIDs() {
 		if agent, ok := al.registry.GetAgent(agentID); ok {
diff --git a/pkg/agent/registry.go b/pkg/agent/registry.go
index 0e7973dc3e..58b7ce4404 100644
--- a/pkg/agent/registry.go
+++ b/pkg/agent/registry.go
@@ -114,6 +114,18 @@ func (r *AgentRegistry) ForEachTool(name string, fn func(tools.Tool)) {
 	}
 }
 
+// Close releases resources held by all registered agents.
+func (r *AgentRegistry) Close() {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	for _, agent := range r.agents {
+		if err := agent.Close(); err != nil {
+			logger.WarnCF("agent", "Failed to close agent",
+				map[string]any{"agent_id": agent.ID, "error": err.Error()})
+		}
+	}
+}
+
 // GetDefaultAgent returns the default agent instance.
 func (r *AgentRegistry) GetDefaultAgent() *AgentInstance {
 	r.mu.RLock()
diff --git a/pkg/session/jsonl_backend.go b/pkg/session/jsonl_backend.go
new file mode 100644
index 0000000000..7f470de153
--- /dev/null
+++ b/pkg/session/jsonl_backend.go
@@ -0,0 +1,81 @@
+package session
+
+import (
+	"context"
+	"log"
+
+	"github.com/sipeed/picoclaw/pkg/memory"
+	"github.com/sipeed/picoclaw/pkg/providers"
+)
+
+// JSONLBackend adapts a memory.Store into the SessionStore interface.
+// Write errors are logged rather than returned, matching the fire-and-forget
+// contract of SessionManager that the agent loop relies on.
+type JSONLBackend struct {
+	store memory.Store
+}
+
+// NewJSONLBackend wraps a memory.Store for use as a SessionStore.
+func NewJSONLBackend(store memory.Store) *JSONLBackend {
+	return &JSONLBackend{store: store}
+}
+
+func (b *JSONLBackend) AddMessage(sessionKey, role, content string) {
+	if err := b.store.AddMessage(context.Background(), sessionKey, role, content); err != nil {
+		log.Printf("session: add message: %v", err)
+	}
+}
+
+func (b *JSONLBackend) AddFullMessage(sessionKey string, msg providers.Message) {
+	if err := b.store.AddFullMessage(context.Background(), sessionKey, msg); err != nil {
+		log.Printf("session: add full message: %v", err)
+	}
+}
+
+func (b *JSONLBackend) GetHistory(key string) []providers.Message {
+	msgs, err := b.store.GetHistory(context.Background(), key)
+	if err != nil {
+		log.Printf("session: get history: %v", err)
+		return []providers.Message{}
+	}
+	return msgs
+}
+
+func (b *JSONLBackend) GetSummary(key string) string {
+	summary, err := b.store.GetSummary(context.Background(), key)
+	if err != nil {
+		log.Printf("session: get summary: %v", err)
+		return ""
+	}
+	return summary
+}
+
+func (b *JSONLBackend) SetSummary(key, summary string) {
+	if err := b.store.SetSummary(context.Background(), key, summary); err != nil {
+		log.Printf("session: set summary: %v", err)
+	}
+}
+
+func (b *JSONLBackend) SetHistory(key string, history []providers.Message) {
+	if err := b.store.SetHistory(context.Background(), key, history); err != nil {
+		log.Printf("session: set history: %v", err)
+	}
+}
+
+func (b *JSONLBackend) TruncateHistory(key string, keepLast int) {
+	if err := b.store.TruncateHistory(context.Background(), key, keepLast); err != nil {
+		log.Printf("session: truncate history: %v", err)
+	}
+}
+
+// Save persists session state. Since the JSONL store fsyncs every write
+// immediately, the data is already durable. Save runs compaction to reclaim
+// space from logically truncated messages (no-op when there are none).
+func (b *JSONLBackend) Save(key string) error {
+	return b.store.Compact(context.Background(), key)
+}
+
+// Close releases resources held by the underlying store.
+func (b *JSONLBackend) Close() error {
+	return b.store.Close()
+}
diff --git a/pkg/session/jsonl_backend_test.go b/pkg/session/jsonl_backend_test.go
new file mode 100644
index 0000000000..40fa019cba
--- /dev/null
+++ b/pkg/session/jsonl_backend_test.go
@@ -0,0 +1,179 @@
+package session_test
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/sipeed/picoclaw/pkg/memory"
+	"github.com/sipeed/picoclaw/pkg/providers"
+	"github.com/sipeed/picoclaw/pkg/session"
+)
+
+// Compile-time interface satisfaction checks.
+var (
+	_ session.SessionStore = (*session.SessionManager)(nil)
+	_ session.SessionStore = (*session.JSONLBackend)(nil)
+)
+
+func newBackend(t *testing.T) *session.JSONLBackend {
+	t.Helper()
+	store, err := memory.NewJSONLStore(t.TempDir())
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { store.Close() })
+	return session.NewJSONLBackend(store)
+}
+
+func TestJSONLBackend_AddAndGetHistory(t *testing.T) {
+	b := newBackend(t)
+
+	b.AddMessage("s1", "user", "hello")
+	b.AddMessage("s1", "assistant", "hi")
+
+	history := b.GetHistory("s1")
+	if len(history) != 2 {
+		t.Fatalf("got %d messages, want 2", len(history))
+	}
+	if history[0].Role != "user" || history[0].Content != "hello" {
+		t.Errorf("msg[0] = %+v", history[0])
+	}
+	if history[1].Role != "assistant" || history[1].Content != "hi" {
+		t.Errorf("msg[1] = %+v", history[1])
+	}
+}
+
+func TestJSONLBackend_AddFullMessage(t *testing.T) {
+	b := newBackend(t)
+
+	msg := providers.Message{
+		Role:    "assistant",
+		Content: "done",
+		ToolCalls: []providers.ToolCall{
+			{ID: "tc1", Function: &providers.FunctionCall{Name: "read_file", Arguments: `{"path":"x"}`}},
+		},
+	}
+	b.AddFullMessage("s1", msg)
+
+	history := b.GetHistory("s1")
+	if len(history) != 1 {
+		t.Fatalf("got %d, want 1", len(history))
+	}
+	if len(history[0].ToolCalls) != 1 || history[0].ToolCalls[0].ID != "tc1" {
+		t.Errorf("tool calls = %+v", history[0].ToolCalls)
+	}
+}
+
+func TestJSONLBackend_Summary(t *testing.T) {
+	b := newBackend(t)
+
+	if got := b.GetSummary("s1"); got != "" {
+		t.Errorf("got %q, want empty", got)
+	}
+
+	b.SetSummary("s1", "test summary")
+	if got := b.GetSummary("s1"); got != "test summary" {
+		t.Errorf("got %q, want %q", got, "test summary")
+	}
+}
+
+func TestJSONLBackend_TruncateAndSave(t *testing.T) {
+	b := newBackend(t)
+
+	for i := 0; i < 10; i++ {
+		b.AddMessage("s1", "user", fmt.Sprintf("msg %d", i))
+	}
+	b.TruncateHistory("s1", 3)
+
+	history := b.GetHistory("s1")
+	if len(history) != 3 {
+		t.Fatalf("got %d, want 3", len(history))
+	}
+	if history[0].Content != "msg 7" {
+		t.Errorf("got %q, want %q", history[0].Content, "msg 7")
+	}
+
+	// Save triggers compaction.
+	if err := b.Save("s1"); err != nil {
+		t.Fatal(err)
+	}
+
+	// Messages still accessible after compaction.
+	history = b.GetHistory("s1")
+	if len(history) != 3 {
+		t.Fatalf("after save: got %d, want 3", len(history))
+	}
+}
+
+func TestJSONLBackend_SetHistory(t *testing.T) {
+	b := newBackend(t)
+	b.AddMessage("s1", "user", "old")
+
+	b.SetHistory("s1", []providers.Message{
+		{Role: "user", Content: "new1"},
+		{Role: "assistant", Content: "new2"},
+	})
+
+	history := b.GetHistory("s1")
+	if len(history) != 2 {
+		t.Fatalf("got %d, want 2", len(history))
+	}
+	if history[0].Content != "new1" {
+		t.Errorf("got %q, want %q", history[0].Content, "new1")
+	}
+}
+
+func TestJSONLBackend_EmptySession(t *testing.T) {
+	b := newBackend(t)
+
+	history := b.GetHistory("nonexistent")
+	if history == nil {
+		t.Fatal("got nil, want empty slice")
+	}
+	if len(history) != 0 {
+		t.Errorf("got %d, want 0", len(history))
+	}
+}
+
+func TestJSONLBackend_SessionIsolation(t *testing.T) {
+	b := newBackend(t)
+	b.AddMessage("s1", "user", "session1")
+	b.AddMessage("s2", "user", "session2")
+
+	h1 := b.GetHistory("s1")
+	h2 := b.GetHistory("s2")
+
+	if len(h1) != 1 || h1[0].Content != "session1" {
+		t.Errorf("s1: %+v", h1)
+	}
+	if len(h2) != 1 || h2[0].Content != "session2" {
+		t.Errorf("s2: %+v", h2)
+	}
+}
+
+func TestJSONLBackend_SummarizeFlow(t *testing.T) {
+	// Simulates the real summarization flow in the agent loop:
+	// SetSummary → TruncateHistory → Save
+	b := newBackend(t)
+
+	for i := 0; i < 20; i++ {
+		b.AddMessage("s1", "user", fmt.Sprintf("msg %d", i))
+	}
+
+	b.SetSummary("s1", "conversation about testing")
+	b.TruncateHistory("s1", 4)
+	if err := b.Save("s1"); err != nil {
+		t.Fatal(err)
+	}
+
+	if got := b.GetSummary("s1"); got != "conversation about testing" {
+		t.Errorf("summary = %q", got)
+	}
+	history := b.GetHistory("s1")
+	if len(history) != 4 {
+		t.Fatalf("got %d messages, want 4", len(history))
+	}
+	if history[0].Content != "msg 16" {
+		t.Errorf("first message = %q, want %q", history[0].Content, "msg 16")
+	}
+}
diff --git a/pkg/session/manager.go b/pkg/session/manager.go
index 08f0b0ad21..07f981df17 100644
--- a/pkg/session/manager.go
+++ b/pkg/session/manager.go
@@ -265,6 +265,12 @@ func (sm *SessionManager) loadSessions() error {
 	return nil
 }
 
+// Close is a no-op for the in-memory SessionManager; it satisfies the
+// SessionStore interface so callers can release resources uniformly.
+func (sm *SessionManager) Close() error {
+	return nil
+}
+
 // SetHistory updates the messages of a session.
 func (sm *SessionManager) SetHistory(key string, history []providers.Message) {
 	sm.mu.Lock()
diff --git a/pkg/session/session_store.go b/pkg/session/session_store.go
new file mode 100644
index 0000000000..1d1a2f9675
--- /dev/null
+++ b/pkg/session/session_store.go
@@ -0,0 +1,32 @@
+package session
+
+import "github.com/sipeed/picoclaw/pkg/providers"
+
+// SessionStore defines the persistence operations used by the agent loop.
+// Both SessionManager (legacy JSON backend) and JSONLBackend satisfy this
+// interface, allowing the storage layer to be swapped without touching the
+// agent loop code.
+//
+// Write methods (Add*, Set*, Truncate*) are fire-and-forget: they do not
+// return errors. Implementations should log failures internally. This
+// matches the original SessionManager contract that the agent loop relies on.
+type SessionStore interface {
+	// AddMessage appends a simple role/content message to the session.
+	AddMessage(sessionKey, role, content string)
+	// AddFullMessage appends a complete message including tool calls.
+	AddFullMessage(sessionKey string, msg providers.Message)
+	// GetHistory returns the full message history for the session.
+	GetHistory(key string) []providers.Message
+	// GetSummary returns the conversation summary, or "" if none.
+	GetSummary(key string) string
+	// SetSummary replaces the conversation summary.
+	SetSummary(key, summary string)
+	// SetHistory replaces the full message history.
+	SetHistory(key string, history []providers.Message)
+	// TruncateHistory keeps only the last keepLast messages.
+	TruncateHistory(key string, keepLast int)
+	// Save persists any pending state to durable storage.
+	Save(key string) error
+	// Close releases resources held by the store.
+	Close() error
+}