diff --git a/coderd/exp_chats.go b/coderd/exp_chats.go
index 86713b8201..44d3ac3886 100644
--- a/coderd/exp_chats.go
+++ b/coderd/exp_chats.go
@@ -1830,6 +1830,20 @@ func (api *API) postChatMessages(rw http.ResponseWriter, r *http.Request) {
 		}
 	}
 
+	busyBehavior := chatd.SendMessageBusyBehaviorQueue
+	switch req.BusyBehavior {
+	case codersdk.ChatBusyBehaviorInterrupt:
+		busyBehavior = chatd.SendMessageBusyBehaviorInterrupt
+	case codersdk.ChatBusyBehaviorQueue, "":
+		// Default to queue.
+	default:
+		httpapi.Write(ctx, rw, http.StatusBadRequest, codersdk.Response{
+			Message: "Invalid busy_behavior value.",
+			Detail:  `Must be "queue" or "interrupt".`,
+		})
+		return
+	}
+
 	sendResult, sendErr := api.chatDaemon.SendMessage(
 		ctx,
 		chatd.SendMessageOptions{
@@ -1837,7 +1851,7 @@ func (api *API) postChatMessages(rw http.ResponseWriter, r *http.Request) {
 			CreatedBy:     apiKey.UserID,
 			Content:       contentBlocks,
 			ModelConfigID: req.ModelConfigID,
-			BusyBehavior:  chatd.SendMessageBusyBehaviorQueue,
+			BusyBehavior:  busyBehavior,
 			MCPServerIDs:  req.MCPServerIDs,
 		},
 	)
diff --git a/codersdk/chats.go b/codersdk/chats.go
index 1a4a865d08..f62a843553 100644
--- a/codersdk/chats.go
+++ b/codersdk/chats.go
@@ -369,11 +369,27 @@ type UpdateChatRequest struct {
 	Labels   *map[string]string `json:"labels,omitempty"`
 }
 
+// ChatBusyBehavior controls what happens when a user sends a message
+// while the chat is already processing.
+type ChatBusyBehavior string
+
+const (
+	// ChatBusyBehaviorQueue queues the message for processing after
+	// the current run finishes.
+	ChatBusyBehaviorQueue ChatBusyBehavior = "queue"
+	// ChatBusyBehaviorInterrupt queues the message and interrupts
+	// the active run. The partial assistant response is persisted
+	// before the queued message is promoted, preserving correct
+	// conversation order.
+	ChatBusyBehaviorInterrupt ChatBusyBehavior = "interrupt"
+)
+
 // CreateChatMessageRequest is the request to add a message to a chat.
 type CreateChatMessageRequest struct {
-	Content       []ChatInputPart `json:"content"`
-	ModelConfigID *uuid.UUID      `json:"model_config_id,omitempty" format:"uuid"`
-	MCPServerIDs  *[]uuid.UUID    `json:"mcp_server_ids,omitempty" format:"uuid"`
+	Content       []ChatInputPart  `json:"content"`
+	ModelConfigID *uuid.UUID       `json:"model_config_id,omitempty" format:"uuid"`
+	MCPServerIDs  *[]uuid.UUID     `json:"mcp_server_ids,omitempty" format:"uuid"`
+	BusyBehavior  ChatBusyBehavior `json:"busy_behavior,omitempty" enums:"queue,interrupt"`
 }
 
 // EditChatMessageRequest is the request to edit a user message in a chat.
diff --git a/site/src/api/typesGenerated.ts b/site/src/api/typesGenerated.ts
index f502de0395..0e657b5d14 100644
--- a/site/src/api/typesGenerated.ts
+++ b/site/src/api/typesGenerated.ts
@@ -1215,6 +1215,11 @@ export interface Chat {
 	readonly last_injected_context?: readonly ChatMessagePart[];
 }
 
+// From codersdk/chats.go
+export type ChatBusyBehavior = "interrupt" | "queue";
+
+export const ChatBusyBehaviors: ChatBusyBehavior[] = ["interrupt", "queue"];
+
 // From codersdk/chats.go
 /**
  * ChatCompactionThresholdKeyPrefix scopes per-model chat compaction
@@ -2338,6 +2343,7 @@ export interface CreateChatMessageRequest {
 	readonly content: readonly ChatInputPart[];
 	readonly model_config_id?: string;
 	readonly mcp_server_ids?: string[];
+	readonly busy_behavior?: ChatBusyBehavior;
 }
 
 // From codersdk/chats.go