diff --git a/.github/workflows/codex-mention-response.yml b/.github/workflows/codex-mention-response.yml
index 26f43d43..369c2d31 100644
--- a/.github/workflows/codex-mention-response.yml
+++ b/.github/workflows/codex-mention-response.yml
@@ -127,7 +127,7 @@ jobs:
         with:
           openai-api-key: ${{ secrets.OPENAI_API_KEY }}
           responses-api-endpoint: ${{ secrets.OPENAI_BASE_URL }}
-          model: ${{ vars.OPENAI_MODEL || 'gpt-5.2-codex' }}
+          model: ${{ vars.OPENAI_MODEL || 'gpt-5.4' }}
           effort: ${{ vars.OPENAI_EFFORT || 'high' }}
           sandbox: danger-full-access
           safety-strategy: drop-sudo
diff --git a/.github/workflows/issue-auto-response.yml b/.github/workflows/issue-auto-response.yml
index 31e837f7..2e2ff7f9 100644
--- a/.github/workflows/issue-auto-response.yml
+++ b/.github/workflows/issue-auto-response.yml
@@ -73,7 +73,7 @@ jobs:
         with:
           openai-api-key: ${{ secrets.OPENAI_API_KEY }}
           responses-api-endpoint: ${{ secrets.OPENAI_BASE_URL }}
-          model: ${{ vars.OPENAI_MODEL || 'gpt-5.2-codex' }}
+          model: ${{ vars.OPENAI_MODEL || 'gpt-5.4' }}
           effort: ${{ vars.OPENAI_EFFORT || 'high' }}
           sandbox: danger-full-access
           safety-strategy: drop-sudo
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index c48b1c48..7017d447 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -13,7 +13,7 @@ Thank you for your interest in contributing to HAPI! We welcome bug fixes, featu
 
 If you are using AI tools to generate code ("Vibe Coding"), please note:
 
-**We only accept code generated by the GPT-5.2-codex model.**
+**We only accept code generated by the GPT-5.4 model.**
 
 Pull requests containing code generated by other AI models (including other GPT versions, Claude, Gemini, or any other LLM) will be rejected. This policy helps us maintain consistency and quality standards across the codebase.