fix(mothership): continue Sim Chat block conversations

Author: Sg312

apps/sim/app/api/mothership/execute/route.test.ts

@@ -207,6 +207,32 @@ describe('mothership private trace provenance transport', () => {
     )
   })
 
+  it.each([true, false, undefined])(
+    'forwards conversation replay opt-in: %s',
+    async (useConversationHistory) => {
+      mockRunHeadlessCopilotLifecycle.mockImplementation(
+        async (payload: Record<string, unknown>) => {
+          expect(payload.useConversationHistory).toBe(useConversationHistory)
+          return successResult()
+        }
+      )
+      const response = await POST(
+        createMockRequest(
+          'POST',
+          { ...requestBody, useConversationHistory },
+          {
+            'X-Sim-Mcp-Delegation': 'signed-block',
+            Authorization: 'Bearer internal',
+            'x-sim-billing-attribution': 'billing',
+          },
+          'http://localhost:3000/api/mothership/execute'
+        ),
+        undefined
+      )
+      expect(response.status).toBe(200)
+    }
+  )
+
   it('omits an absent response format from the headless lifecycle payload', async () => {
     mockRunHeadlessCopilotLifecycle.mockImplementation(async (payload: Record<string, unknown>) => {
       expect(payload).not.toHaveProperty('responseFormat')

apps/sim/app/api/mothership/execute/route.ts

@@ -148,6 +148,7 @@ export const POST = withRouteHandler(async (req: NextRequest) => {
     const {
       messages,
       responseFormat,
+      useConversationHistory,
       modelSelection,
       effort,
       workspaceId,
@@ -301,6 +302,7 @@ export const POST = withRouteHandler(async (req: NextRequest) => {
     )
     const requestPayload: Record<string, unknown> = {
       messages: wireMessages,
+      ...(useConversationHistory !== undefined ? { useConversationHistory } : {}),
       ...(modelSelection ? { modelSelection } : {}),
       ...(effort ? { effort } : {}),
       ...(responseFormat !== undefined ? { responseFormat } : {}),

apps/sim/executor/handlers/mothership/mothership-handler.test.ts

@@ -794,6 +794,7 @@ describe('MothershipBlockHandler', () => {
       modelSelection: { model: 'gpt-6-astra', fastMode: false },
       effort: 'high',
       messages: [{ role: 'user', content: 'Hello from workflow' }],
+      useConversationHistory: true,
       workspaceId: 'workspace-1',
       userId: 'user-1',
       chatId: resolveMothershipConversation('workspace-1', 'chat-uuid').chatId,
@@ -880,6 +881,7 @@ describe('MothershipBlockHandler', () => {
       modelSelection: { model: 'gpt-6-astra', fastMode: false },
       effort: 'high',
       messages: [{ role: 'user', content: 'Continue this thread' }],
+      useConversationHistory: true,
       workspaceId: 'workspace-1',
       userId: 'user-1',
       chatId: resolveMothershipConversation('workspace-1', 'existing-chat-id').chatId,

apps/sim/executor/handlers/mothership/mothership-handler.ts

@@ -988,6 +988,7 @@ export class MothershipBlockHandler implements BlockHandler {
     const effort = ChatPayloadSchema.shape.effort.parse(inputs.effort ?? 'high')
     const body: Record<string, unknown> = {
       messages,
+      useConversationHistory: true,
       modelSelection,
       effort,
       workspaceId: ctx.workspaceId || '',

apps/sim/lib/api/contracts/mothership-chats.ts

@@ -116,6 +116,7 @@ const mothershipExecuteMcpToolSchema = z
   .passthrough()
 
 export const mothershipExecuteBodySchema = z.object({
+  useConversationHistory: z.boolean().optional(),
   effort: ChatPayloadSchema.shape.effort,
   modelSelection: ChatPayloadSchema.shape.modelSelection,
   messages: z.array(mothershipExecuteMessageSchema).min(1, 'At least one message is required'),

apps/sim/lib/mothership/generated/protocol.ts

@@ -395,7 +395,7 @@ export interface ProtocolMismatch {
 }
 
 /**
- * POST /api/mothership/execute — the one-shot headless surface used by Sim Chat blocks.
+ * POST /api/mothership/execute — headless execution, with optional conversation replay.
  * The caller supplies the conversation and authorized catalog selectors. The worker
  * runs one bounded loop and streams mothership-stream-v1 frames. No skills or CLI;
  * discovery and execution resolve selected operations through Sim.
@@ -404,6 +404,8 @@ export interface ExecuteRequest extends StreamResponseReceipt {
   effort?: ChatRequest["effort"];
   modelSelection?: ModelSelection | undefined;
   messages: ExecuteMessage[];
+  /** Replay stored turns before one new user message (optionally preceded by a system prompt). */
+  useConversationHistory?: boolean | undefined;
   /** JSON schema for structured output; enforced by instruction + caller-side validation. */
   responseFormat?: unknown | undefined;
   userId: string;