diff --git a/src/index.ts b/src/index.ts
index 2c54d35..1b4050f 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -179,7 +179,7 @@ function hasErrorCode(error: unknown, code: string): boolean {
 	return Boolean(error && typeof error === "object" && "code" in error && error.code === code);
 }
 
-const GPT_APPLY_PATCH_PROVIDERS = new Set(["openai", "azure-openai-responses", "github-copilot"]);
+const GPT_APPLY_PATCH_PROVIDERS = new Set(["openai", "openai-codex", "azure-openai-responses", "github-copilot"]);
 export const PATCH_PREVIEW_MAX_LINES = 16;
 export const PATCH_PREVIEW_MAX_CHARS = 4000;
 const PATCH_PREVIEW_HEAD_LINES = 8;
diff --git a/test/index.test.ts b/test/index.test.ts
index 403aa50..cf77d05 100644
--- a/test/index.test.ts
+++ b/test/index.test.ts
@@ -788,6 +788,7 @@ EOF`;
 
 	it("#given model metadata #when checking GPT activation #then only OpenAI GPT models match", () => {
 		expect(isOpenAIGptModel({ provider: "openai", id: "gpt-5" })).toBe(true);
+		expect(isOpenAIGptModel({ provider: "openai-codex", id: "gpt-5.5" })).toBe(true);
 		expect(isOpenAIGptModel({ provider: "openai", id: "o1" })).toBe(false);
 		expect(isOpenAIGptModel({ provider: "anthropic", id: "gpt-5" })).toBe(false);
 	});