From fdd0a9ce65f2b2e87c633f45be8c8996ddfe8db2 Mon Sep 17 00:00:00 2001
From: Marco Beretta <81851188+berry-13@users.noreply.github.com>
Date: Wed, 29 Jul 2026 02:28:15 +0200
Subject: [PATCH] fix(import): keep imported ChatGPT conversations on a
 configured model

default_model_slug is a historical ChatGPT identifier - auto, research,
gpt-5-t - that no endpoint serves, and it was being written as the
conversation's own model, which is what the next prompt is sent with. The
messages keep their historical slug for display; the conversation resolves
to the configured default, as the Claude and Grok converters already do.
---
 packages/api/src/import/chatgpt/convert.spec.ts |  7 +++++--
 packages/api/src/import/chatgpt/convert.ts      | 12 +++++++++---
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/packages/api/src/import/chatgpt/convert.spec.ts b/packages/api/src/import/chatgpt/convert.spec.ts
index 8823f803bd..4ef4ef8823 100644
--- a/packages/api/src/import/chatgpt/convert.spec.ts
+++ b/packages/api/src/import/chatgpt/convert.spec.ts
@@ -25,7 +25,7 @@ const OPTIONS = {
 };
 
 describe('convertConversation', () => {
-  it('carries archive, pin, model, and external id onto the conversation', () => {
+  it('carries archive, pin, and external id onto the conversation, on the configured model', () => {
     const result = convertConversation(
       conversation({
         root: { id: 'root', message: null, parent: null, children: ['a'] },
@@ -46,7 +46,10 @@ describe('convertConversation', () => {
 
     expect(result.isArchived).toBe(true);
     expect(result.pinned).toBe(true);
-    expect(result.model).toBe('gpt-5-thinking');
+    /** Not `default_model_slug` ('gpt-5-thinking'): the conversation's model is
+     * what its next prompt is sent with, and a historical ChatGPT slug is not a
+     * model any endpoint serves. */
+    expect(result.model).toBe('gpt-4o');
     expect(result.externalId).toBe('ext-1');
     expect(result.title).toBe('Trip planning');
   });
diff --git a/packages/api/src/import/chatgpt/convert.ts b/packages/api/src/import/chatgpt/convert.ts
index 138209d237..24631980f9 100644
--- a/packages/api/src/import/chatgpt/convert.ts
+++ b/packages/api/src/import/chatgpt/convert.ts
@@ -210,8 +210,6 @@ export function convertConversation(
 
   orderTree(messages);
 
-  const { model } = resolveModel(conv.default_model_slug ?? undefined, options.defaultModel);
-
   return {
     conversationId: uuidv4(),
     externalId: conv.conversation_id,
@@ -219,7 +217,15 @@ export function convertConversation(
     createdAt: new Date(fallbackTime),
     isArchived: conv.is_archived === true,
     pinned: conv.is_starred === true || conv.pinned_time != null,
-    model,
+    /** The conversation's model is what its *next* prompt is sent with, so it
+     * has to be a model this deployment actually serves. `default_model_slug`
+     * is a historical ChatGPT identifier — `auto`, `research`, `gpt-5-t` — that
+     * no endpoint accepts, and setting it here would leave every imported
+     * conversation unusable until the user picked a model by hand. The
+     * per-message `model` keeps the historical slug for display, which is
+     * where it belongs; the Claude and Grok converters resolve this field the
+     * same way. */
+    model: options.defaultModel,
     messages,
   };
 }