diff --git a/.yarn/patches/@opeoginni-github-copilot-openai-compatible-npm-0.1.18-3f65760532.patch b/.yarn/patches/@opeoginni-github-copilot-openai-compatible-npm-0.1.18-3f65760532.patch
new file mode 100644
index 0000000000..cebfdd00a5
--- /dev/null
+++ b/.yarn/patches/@opeoginni-github-copilot-openai-compatible-npm-0.1.18-3f65760532.patch
@@ -0,0 +1,44 @@
+diff --git a/dist/index.js b/dist/index.js
+index 53f411e55a4c9a06fd29bb4ab8161c4ad15980cd..71b91f196c8b886ed90dd237dec5625d79d5677e 100644
+--- a/dist/index.js
++++ b/dist/index.js
+@@ -12676,10 +12676,13 @@ var OpenAIResponsesLanguageModel = class {
+                   }
+                 });
+               } else if (value.item.type === "message") {
+-                controller.enqueue({
+-                  type: "text-end",
+-                  id: value.item.id
+-                });
++                // Fix for gpt-5-codex: use currentTextId to ensure text-end matches text-start
++                if (currentTextId) {
++                  controller.enqueue({
++                    type: "text-end",
++                    id: currentTextId
++                  });
++                }
+                 currentTextId = null;
+               } else if (isResponseOutputItemDoneReasoningChunk(value)) {
+                 const activeReasoningPart = activeReasoning[value.item.id];
+diff --git a/dist/index.mjs b/dist/index.mjs
+index 7719264da3c49a66c2626082f6ccaae6e3ef5e89..090fd8cf142674192a826148428ed6a0c4a54e35 100644
+--- a/dist/index.mjs
++++ b/dist/index.mjs
+@@ -12670,10 +12670,13 @@ var OpenAIResponsesLanguageModel = class {
+                   }
+                 });
+               } else if (value.item.type === "message") {
+-                controller.enqueue({
+-                  type: "text-end",
+-                  id: value.item.id
+-                });
++                // Fix for gpt-5-codex: use currentTextId to ensure text-end matches text-start
++                if (currentTextId) {
++                  controller.enqueue({
++                    type: "text-end",
++                    id: currentTextId
++                  });
++                }
+                 currentTextId = null;
+               } else if (isResponseOutputItemDoneReasoningChunk(value)) {
+                 const activeReasoningPart = activeReasoning[value.item.id];
diff --git a/package.json b/package.json
index e82153922c..1dad6a9f5a 100644
--- a/package.json
+++ b/package.json
@@ -154,7 +154,7 @@
     "@opentelemetry/sdk-trace-base": "^2.0.0",
     "@opentelemetry/sdk-trace-node": "^2.0.0",
     "@opentelemetry/sdk-trace-web": "^2.0.0",
-    "@opeoginni/github-copilot-openai-compatible": "0.1.18",
+    "@opeoginni/github-copilot-openai-compatible": "patch:@opeoginni/github-copilot-openai-compatible@npm%3A0.1.18#~/.yarn/patches/@opeoginni-github-copilot-openai-compatible-npm-0.1.18-3f65760532.patch",
     "@playwright/test": "^1.52.0",
     "@radix-ui/react-context-menu": "^2.2.16",
     "@reduxjs/toolkit": "^2.2.5",
diff --git a/src/renderer/src/aiCore/legacy/clients/openai/OpenAIBaseClient.ts b/src/renderer/src/aiCore/legacy/clients/openai/OpenAIBaseClient.ts
index 79762e9474..71ed1c95fe 100644
--- a/src/renderer/src/aiCore/legacy/clients/openai/OpenAIBaseClient.ts
+++ b/src/renderer/src/aiCore/legacy/clients/openai/OpenAIBaseClient.ts
@@ -1,4 +1,5 @@
 import { loggerService } from '@logger'
+import { COPILOT_DEFAULT_HEADERS } from '@renderer/aiCore/provider/constants'
 import {
   isClaudeReasoningModel,
   isOpenAIReasoningModel,
@@ -166,7 +167,8 @@ export abstract class OpenAIBaseClient<
         baseURL: this.getBaseURL(),
         defaultHeaders: {
           ...this.defaultHeaders(),
-          ...this.provider.extra_headers
+          ...this.provider.extra_headers,
+          ...(this.provider.id === 'copilot' ? COPILOT_DEFAULT_HEADERS : {})
         }
       }) as TSdkInstance
     }
diff --git a/yarn.lock b/yarn.lock
index 4fcea693ba..2d5bffcfd0 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -7421,6 +7421,18 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@opeoginni/github-copilot-openai-compatible@patch:@opeoginni/github-copilot-openai-compatible@npm%3A0.1.18#~/.yarn/patches/@opeoginni-github-copilot-openai-compatible-npm-0.1.18-3f65760532.patch":
+  version: 0.1.18
+  resolution: "@opeoginni/github-copilot-openai-compatible@patch:@opeoginni/github-copilot-openai-compatible@npm%3A0.1.18#~/.yarn/patches/@opeoginni-github-copilot-openai-compatible-npm-0.1.18-3f65760532.patch::version=0.1.18&hash=1cf9d0"
+  dependencies:
+    "@ai-sdk/openai": "npm:^2.0.42"
+    "@ai-sdk/openai-compatible": "npm:^1.0.19"
+    "@ai-sdk/provider": "npm:^2.1.0-beta.4"
+    "@ai-sdk/provider-utils": "npm:^3.0.10"
+  checksum: 10c0/cfffc031d2742068d20baed0e0ade6e9182c29ee7a425fa64262c04023ae75220b8b944ad2c9554255681e325fa1a70ec5e1f961b5f7370c871e70cbaeac0e79
+  languageName: node
+  linkType: hard
+
 "@oxc-project/runtime@npm:0.71.0":
   version: 0.71.0
   resolution: "@oxc-project/runtime@npm:0.71.0"
@@ -13993,7 +14005,7 @@ __metadata:
     "@opentelemetry/sdk-trace-base": "npm:^2.0.0"
     "@opentelemetry/sdk-trace-node": "npm:^2.0.0"
     "@opentelemetry/sdk-trace-web": "npm:^2.0.0"
-    "@opeoginni/github-copilot-openai-compatible": "npm:0.1.18"
+    "@opeoginni/github-copilot-openai-compatible": "patch:@opeoginni/github-copilot-openai-compatible@npm%3A0.1.18#~/.yarn/patches/@opeoginni-github-copilot-openai-compatible-npm-0.1.18-3f65760532.patch"
     "@playwright/test": "npm:^1.52.0"
     "@radix-ui/react-context-menu": "npm:^2.2.16"
     "@reduxjs/toolkit": "npm:^2.2.5"