diff --git a/cmd/root/run.go b/cmd/root/run.go
index 9d60391ad..5137d5eb6 100644
--- a/cmd/root/run.go
+++ b/cmd/root/run.go
@@ -578,6 +578,7 @@ func createUserMessageWithAttachment(agentFilename, userContent, attachmentPath
 		Message: chat.Message{
 			Role:         chat.MessageRoleUser,
 			MultiContent: multiContent,
+			CreatedAt:    time.Now().Format(time.RFC3339),
 		},
 	}
 }
diff --git a/pkg/chat/chat.go b/pkg/chat/chat.go
index e5b03ce41..78b107188 100644
--- a/pkg/chat/chat.go
+++ b/pkg/chat/chat.go
@@ -1,6 +1,8 @@
 package chat
 
-import "github.com/docker/cagent/pkg/tools"
+import (
+	"github.com/docker/cagent/pkg/tools"
+)
 
 type MessageRole string
 
@@ -56,6 +58,9 @@ type Message struct {
 
 	// For Role=tool prompts this should be set to the ID given in the assistant's prior request to call a tool.
 	ToolCallID string `json:"tool_call_id,omitempty"`
+
+	// CreatedAt is the time the message was created
+	CreatedAt string `json:"created_at,omitempty"`
 }
 
 type MessagePart struct {
diff --git a/pkg/runtime/runtime.go b/pkg/runtime/runtime.go
index 42e80c08c..bdf3e1477 100644
--- a/pkg/runtime/runtime.go
+++ b/pkg/runtime/runtime.go
@@ -8,6 +8,7 @@ import (
 	"io"
 	"log/slog"
 	"strings"
+	"time"
 
 	"github.com/docker/cagent/pkg/agent"
 	"github.com/docker/cagent/pkg/chat"
@@ -223,6 +224,7 @@ func (r *Runtime) RunStream(ctx context.Context, sess *session.Session) <-chan E
 				Role:      chat.MessageRoleAssistant,
 				Content:   content,
 				ToolCalls: calls,
+				CreatedAt: time.Now().Format(time.RFC3339),
 			}
 
 			sess.AddMessage(session.NewAgentMessage(a, &assistantMessage))
@@ -544,6 +546,7 @@ func (r *Runtime) runTool(ctx context.Context, tool tools.Tool, toolCall tools.T
 		Role:       chat.MessageRoleTool,
 		Content:    res.Output,
 		ToolCallID: toolCall.ID,
+		CreatedAt:  time.Now().Format(time.RFC3339),
 	}
 	sess.AddMessage(session.NewAgentMessage(a, &toolResponseMsg))
 }
@@ -584,6 +587,7 @@ func (r *Runtime) runAgentTool(ctx context.Context, handler ToolHandler, sess *s
 		Role:       chat.MessageRoleTool,
 		Content:    output,
 		ToolCallID: toolCall.ID,
+		CreatedAt:  time.Now().Format(time.RFC3339),
 	}
 	sess.AddMessage(session.NewAgentMessage(a, &toolResponseMsg))
 }
@@ -599,6 +603,7 @@ func (r *Runtime) addToolRejectedResponse(sess *session.Session, toolCall tools.
 		Role:       chat.MessageRoleTool,
 		Content:    result,
 		ToolCallID: toolCall.ID,
+		CreatedAt:  time.Now().Format(time.RFC3339),
 	}
 	sess.AddMessage(session.NewAgentMessage(a, &toolResponseMsg))
 }
@@ -614,6 +619,7 @@ func (r *Runtime) addToolCancelledResponse(sess *session.Session, toolCall tools
 		Role:       chat.MessageRoleTool,
 		Content:    result,
 		ToolCallID: toolCall.ID,
+		CreatedAt:  time.Now().Format(time.RFC3339),
 	}
 	sess.AddMessage(session.NewAgentMessage(a, &toolResponseMsg))
 }
diff --git a/pkg/session/session.go b/pkg/session/session.go
index 10fd13e6e..f7fa11b74 100644
--- a/pkg/session/session.go
+++ b/pkg/session/session.go
@@ -74,8 +74,9 @@ func UserMessage(agentFilename, content string) *Message {
 		AgentFilename: agentFilename,
 		AgentName:     "",
 		Message: chat.Message{
-			Role:    chat.MessageRoleUser,
-			Content: content,
+			Role:      chat.MessageRoleUser,
+			Content:   content,
+			CreatedAt: time.Now().Format(time.RFC3339),
 		},
 	}
 }
@@ -93,8 +94,9 @@ func SystemMessage(content string) *Message {
 		AgentFilename: "",
 		AgentName:     "",
 		Message: chat.Message{
-			Role:    chat.MessageRoleSystem,
-			Content: content,
+			Role:      chat.MessageRoleSystem,
+			Content:   content,
+			CreatedAt: time.Now().Format(time.RFC3339),
 		},
 	}
 }
@@ -199,8 +201,9 @@ func (s *Session) GetMessages(a *agent.Agent) []chat.Message {
 		}
 
 		messages = append(messages, chat.Message{
-			Role:    "system",
-			Content: "You are a multi-agent system, make sure to answer the user query in the most helpful way possible. You have access to these sub-agents:\n" + subAgentsStr + "\nIMPORTANT: You can ONLY transfer tasks to the agents listed above using their ID. The valid agent IDs are: " + strings.Join(validAgentIDs, ", ") + ". You MUST NOT attempt to transfer to any other agent IDs - doing so will cause system errors.\n\nIf you are the best to answer the question according to your description, you can answer it.\n\nIf another agent is better for answering the question according to its description, call `transfer_task` function to transfer the question to that agent using the agent's ID. When transferring, do not generate any text other than the function call.\n\n",
+			Role:      "system",
+			Content:   "You are a multi-agent system, make sure to answer the user query in the most helpful way possible. You have access to these sub-agents:\n" + subAgentsStr + "\nIMPORTANT: You can ONLY transfer tasks to the agents listed above using their ID. The valid agent IDs are: " + strings.Join(validAgentIDs, ", ") + ". You MUST NOT attempt to transfer to any other agent IDs - doing so will cause system errors.\n\nIf you are the best to answer the question according to your description, you can answer it.\n\nIf another agent is better for answering the question according to its description, call `transfer_task` function to transfer the question to that agent using the agent's ID. When transferring, do not generate any text other than the function call.\n\n",
+			CreatedAt: time.Now().Format(time.RFC3339),
 		})
 	}
 
@@ -210,15 +213,17 @@ func (s *Session) GetMessages(a *agent.Agent) []chat.Message {
 	}
 
 	messages = append(messages, chat.Message{
-		Role:    chat.MessageRoleSystem,
-		Content: a.Instruction() + "\n\n" + date,
+		Role:      chat.MessageRoleSystem,
+		Content:   a.Instruction() + "\n\n" + date,
+		CreatedAt: time.Now().Format(time.RFC3339),
 	})
 
 	for _, tool := range a.ToolSets() {
 		if tool.Instructions() != "" {
 			messages = append(messages, chat.Message{
-				Role:    chat.MessageRoleSystem,
-				Content: tool.Instructions(),
+				Role:      chat.MessageRoleSystem,
+				Content:   tool.Instructions(),
+				CreatedAt: time.Now().Format(time.RFC3339),
 			})
 		}
 	}
@@ -233,8 +238,9 @@ func (s *Session) GetMessages(a *agent.Agent) []chat.Message {
 
 	if lastSummaryIndex != -1 {
 		messages = append(messages, chat.Message{
-			Role:    chat.MessageRoleSystem,
-			Content: "Session Summary: " + s.Messages[lastSummaryIndex].Summary,
+			Role:      chat.MessageRoleSystem,
+			Content:   "Session Summary: " + s.Messages[lastSummaryIndex].Summary,
+			CreatedAt: time.Now().Format(time.RFC3339),
 		})
 	}