diff --git a/cmd/olliesrv/internal/agent/agent.go b/cmd/olliesrv/internal/agent/agent.go
index 88e47e6..f29403d 100644
--- a/cmd/olliesrv/internal/agent/agent.go
+++ b/cmd/olliesrv/internal/agent/agent.go
@@ -56,6 +56,13 @@ type Agent struct {
 	save            func()                      // trigger debounced persistence
 	flush           func()                      // immediately flush persistence
 	onStateChange   func(agentID, state string) // optional callback for state changes
+
+	// Chat log — the rendered output stream, exposed via 9P.
+	chatMu   sync.RWMutex
+	chatLog  []byte
+	chatVers uint32
+	chatCond *sync.Cond
+	plan     []byte
 }
 
 // Backend returns the active backend from the runtime.
@@ -116,6 +123,56 @@ func (ag *Agent) SetName(name string) {
 // ID returns the agent's unique identity.
 func (ag *Agent) ID() string { return ag.id }
 
+// --- Chat log methods ---
+
+// AppendChat appends data to the chat log and notifies stream readers.
+func (ag *Agent) AppendChat(data []byte) {
+	if len(data) == 0 {
+		return
+	}
+	ag.chatMu.Lock()
+	ag.chatLog = append(ag.chatLog, data...)
+	ag.chatVers++
+	ag.chatMu.Unlock()
+	ag.chatCond.Broadcast()
+}
+
+// EnsureTrailingNewline appends a newline if the log doesn't end with one.
+func (ag *Agent) EnsureTrailingNewline() {
+	ag.chatMu.Lock()
+	if len(ag.chatLog) > 0 && ag.chatLog[len(ag.chatLog)-1] != '\n' {
+		ag.chatLog = append(ag.chatLog, '\n')
+	}
+	ag.chatVers++
+	ag.chatMu.Unlock()
+}
+
+// ChatMu returns the chat log mutex for external locking (streaming).
+func (ag *Agent) ChatMu() *sync.RWMutex { return &ag.chatMu }
+
+// ChatCond returns the condvar for blocking chat readers.
+func (ag *Agent) ChatCond() *sync.Cond { return ag.chatCond }
+
+// ChatLog returns the raw chat log bytes (caller must hold ChatMu.RLock).
+func (ag *Agent) ChatLog() []byte { return ag.chatLog }
+
+// Plan returns a copy of the plan.
+func (ag *Agent) Plan() []byte {
+	ag.chatMu.RLock()
+	p := make([]byte, len(ag.plan))
+	copy(p, ag.plan)
+	ag.chatMu.RUnlock()
+	return p
+}
+
+// SetPlan replaces the plan.
+func (ag *Agent) SetPlan(data []byte) {
+	ag.chatMu.Lock()
+	ag.plan = make([]byte, len(data))
+	copy(ag.plan, data)
+	ag.chatMu.Unlock()
+}
+
 // BackendName returns the name of the active backend.
 func (ag *Agent) BackendName() string {
 	if ag.runtime.Backend == nil {
@@ -651,6 +708,7 @@ func NewAgent(cfg AgentParams) *Agent {
 		state:           "idle",
 	}
 	ag.signalCh = make(chan struct{})
+	ag.chatCond = sync.NewCond(ag.chatMu.RLocker())
 	ag.SetSessionEnv(cfg.SessionID)
 	return ag
 }