diff --git a/session/session.go b/session/session.go
index b093a45..72dbd98 100644
--- a/session/session.go
+++ b/session/session.go
@@ -276,7 +276,7 @@ type Config struct {
 	AgentsDir     string
 	SessionsDir   string
 	SessionID     string
-	Uname         string // immutable user principal for 9P identity
+	AgentID       string // unique agent identity
 	CWD           string // working directory for tool execution and system prompt
 	History       *History
 	Runtime       *Runtime
@@ -464,7 +464,7 @@ func New(cfg Config) *Session {
 			history:        cfg.History,
 			runtime:        rt,
 			cwd:            paths.ExpandHome(cfg.CWD),
-			id:             cfg.Uname,
+			id:             cfg.AgentID,
 			agentName:      cfg.AgentName,
 			agentsDir:      cfg.AgentsDir,
 			promptEnvExtra: cfg.PromptEnvExtra,