diff --git a/fs/session/create.go b/fs/session/create.go
index 1c82555..3b86973 100644
--- a/fs/session/create.go
+++ b/fs/session/create.go
@@ -15,6 +15,7 @@ import (
 )
 
 // Create creates a new session from key=value args. Returns the session name.
+// The session is NOT registered yet — CreateAgent must be called to finalize it.
 func Create(rs *rootState, args []string) (string, error) {
 	name := ""
 	for _, arg := range args {
@@ -48,20 +49,13 @@ func Create(rs *rootState, args []string) (string, error) {
 		return "", fmt.Errorf("session already exists: %s", name)
 	}
 
-	sessionCtx, sessionCancel := context.WithCancel(rs.cfg.Ctx)
-	sess := NewSession(sessID, nil, sessionCtx, sessionCancel)
-	sess.SetName(name)
-
-	rs.mu.Lock()
-	rs.sessions[name] = sess
-	rs.mu.Unlock()
-
-	rs.cfg.Log.Info("new session %s (id=%s)", name, sessID)
-	broadcastEvents()
+	rs.cfg.Log.Info("reserved session name %s (id=%s)", name, sessID)
 	return name, nil
 }
 
-// CreateAgent creates and configures an agent within an existing session.
+// CreateAgent creates and configures an agent within a new or existing session.
+// If the session already exists (has a Core), it only replaces the agent.
+// If the session doesn't exist yet, it creates the full session with agent.
 func CreateAgent(rs *rootState, sessName string, args []string) error {
 	backendOverride := ""
 	modelOverride := ""
@@ -102,7 +96,11 @@ func CreateAgent(rs *rootState, sessName string, args []string) error {
 	sess, ok := rs.sessions[sessName]
 	rs.mu.RUnlock()
 	if !ok {
-		return fmt.Errorf("session not found: %s", sessName)
+		// Session doesn't exist yet — create it later after Core is set
+		sessID := coresession.NewSessionID()
+		sessionCtx, sessionCancel := context.WithCancel(rs.cfg.Ctx)
+		sess = NewSession(sessID, nil, sessionCtx, sessionCancel)
+		sess.SetName(sessName)
 	}
 
 	if agentName == "" {
@@ -257,6 +255,13 @@ func CreateAgent(rs *rootState, sessName string, args []string) error {
 	sess.proc = proc
 	sess.mu.Unlock()
 
+	// Register session in the map if not already there
+	rs.mu.Lock()
+	if _, exists := rs.sessions[sessName]; !exists {
+		rs.sessions[sessName] = sess
+	}
+	rs.mu.Unlock()
+
 	core.Agent().Submit(sess.SessionCtx, "/agent "+agentName)
 	if agentAlias != "" {
 		core.Agent().SetName(agentAlias)