The client is not the source of truth (#7438)

Co-authored-by: Douwe Osinga <douwe@squareup.com>
Co-authored-by: Jack Amadeo <jackamadeo@block.xyz>

ui/desktop/openapi.json

@@ -3898,11 +3898,12 @@
           "session_id"
         ],
         "properties": {
-          "conversation_so_far": {
+          "override_conversation": {
             "type": "array",
             "items": {
               "$ref": "#/components/schemas/Message"
             },
+            "description": "Override the server's conversation history. Only use this when you need absolute control\nover the conversation state (e.g., administrative tools). For normal operations, the server\nis the source of truth - use truncate/fork endpoints to modify conversation history instead.",
             "nullable": true
           },
           "recipe_name": {

ui/desktop/src/api/types.gen.ts

@@ -60,7 +60,12 @@ export type CallToolResponse = {
 };
 
 export type ChatRequest = {
-    conversation_so_far?: Array<Message> | null;
+    /**
+     * Override the server's conversation history. Only use this when you need absolute control
+     * over the conversation state (e.g., administrative tools). For normal operations, the server
+     * is the source of truth - use truncate/fork endpoints to modify conversation history instead.
+     */
+    override_conversation?: Array<Message> | null;
     recipe_name?: string | null;
     recipe_version?: string | null;
     session_id: string;

ui/desktop/src/hooks/useChatStream.ts

@@ -590,7 +590,6 @@ export function useChatStream({
           body: {
             session_id: sessionId,
             user_message: newMessage,
-            ...(hasExistingMessages && { conversation_so_far: currentState.messages }),
           },
           throwOnError: true,
           signal: abortControllerRef.current.signal,
@@ -771,7 +770,6 @@ export function useChatStream({
                 body: {
                   session_id: targetSessionId,
                   user_message: updatedUserMessage,
-                  conversation_so_far: truncatedMessages,
                 },
                 throwOnError: true,
                 signal: abortControllerRef.current.signal,