From 7ead0449f25ee5d17cf1828d405e49756587395c Mon Sep 17 00:00:00 2001
From: Timothy Carambat <rambat1010@gmail.com>
Date: Fri, 24 Apr 2026 15:40:05 -0700
Subject: [PATCH] Fix deepseek v4 reasoning inject thoughts (#5527)

* Fix deepseek v4 injectReasoning error
resolves #5509

* comment
---
 server/utils/agents/aibitat/providers/deepseek.js | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/server/utils/agents/aibitat/providers/deepseek.js b/server/utils/agents/aibitat/providers/deepseek.js
index d25ae5f7a..e824b6cd5 100644
--- a/server/utils/agents/aibitat/providers/deepseek.js
+++ b/server/utils/agents/aibitat/providers/deepseek.js
@@ -54,8 +54,20 @@ class DeepSeekProvider extends InheritMultiple([Provider, UnTooled]) {
     return rest;
   }
 
+  /**
+   * Check if the model is a thinking model
+   * because we need to inject reasoning content into the messages
+   * or else the DeepSeek API will return an error for specific models.
+   * There is no official way to predetect if a model will require this
+   * so we have to hardcode the list of thinking models.
+   * @returns {boolean}
+   */
   get #isThinkingModel() {
-    return this.model === "deepseek-reasoner";
+    return [
+      "deepseek-reasoner",
+      "deepseek-v4-flash",
+      "deepseek-v4-pro",
+    ].includes(this.model);
   }
 
   get #tooledOptions() {