From 35907416b8c642b8bd33ab24fcebf0c2ddc93b1b Mon Sep 17 00:00:00 2001
From: hechieh <hechieh@qq.com>
Date: Sun, 22 Mar 2026 19:05:44 +0800
Subject: [PATCH] Fix GitHub Copilot gpt-5.4 endpoint routing

Amp-Thread-ID: https://ampcode.com/threads/T-019d14cd-bc90-70ce-b1ae-87bc97332650
Co-authored-by: Amp <amp@ampcode.com>
---
 internal/registry/model_definitions.go        | 13 +++++++++++
 .../executor/github_copilot_executor.go       | 23 +++++++++++++++++++
 .../executor/github_copilot_executor_test.go  |  7 ++++++
 3 files changed, 43 insertions(+)

diff --git a/internal/registry/model_definitions.go b/internal/registry/model_definitions.go
index 8896a9df..06921a02 100644
--- a/internal/registry/model_definitions.go
+++ b/internal/registry/model_definitions.go
@@ -365,6 +365,19 @@ func GetGitHubCopilotModels() []*ModelInfo {
 			SupportedEndpoints:  []string{"/responses"},
 			Thinking:            &ThinkingSupport{Levels: []string{"none", "low", "medium", "high", "xhigh"}},
 		},
+		{
+			ID:                  "gpt-5.4",
+			Object:              "model",
+			Created:             now,
+			OwnedBy:             "github-copilot",
+			Type:                "github-copilot",
+			DisplayName:         "GPT-5.4",
+			Description:         "OpenAI GPT-5.4 via GitHub Copilot",
+			ContextLength:       200000,
+			MaxCompletionTokens: 32768,
+			SupportedEndpoints:  []string{"/responses"},
+			Thinking:            &ThinkingSupport{Levels: []string{"low", "medium", "high", "xhigh"}},
+		},
 		{
 			ID:                  "claude-haiku-4.5",
 			Object:              "model",
diff --git a/internal/runtime/executor/github_copilot_executor.go b/internal/runtime/executor/github_copilot_executor.go
index b86146a3..abdb3006 100644
--- a/internal/runtime/executor/github_copilot_executor.go
+++ b/internal/runtime/executor/github_copilot_executor.go
@@ -577,9 +577,32 @@ func useGitHubCopilotResponsesEndpoint(sourceFormat sdktranslator.Format, model
 		return true
 	}
 	baseModel := strings.ToLower(thinking.ParseSuffix(model).ModelName)
+	if info := registry.GetGlobalRegistry().GetModelInfo(baseModel, ""); info != nil {
+		if len(info.SupportedEndpoints) > 0 && !containsEndpoint(info.SupportedEndpoints, githubCopilotChatPath) && containsEndpoint(info.SupportedEndpoints, githubCopilotResponsesPath) {
+			return true
+		}
+	}
+	for _, info := range registry.GetGitHubCopilotModels() {
+		if info == nil || !strings.EqualFold(info.ID, baseModel) {
+			continue
+		}
+		if len(info.SupportedEndpoints) > 0 && !containsEndpoint(info.SupportedEndpoints, githubCopilotChatPath) && containsEndpoint(info.SupportedEndpoints, githubCopilotResponsesPath) {
+			return true
+		}
+		break
+	}
 	return strings.Contains(baseModel, "codex")
 }
 
+func containsEndpoint(endpoints []string, endpoint string) bool {
+	for _, item := range endpoints {
+		if item == endpoint {
+			return true
+		}
+	}
+	return false
+}
+
 // flattenAssistantContent converts assistant message content from array format
 // to a joined string. GitHub Copilot requires assistant content as a string;
 // sending it as an array causes Claude models to re-answer all previous prompts.
diff --git a/internal/runtime/executor/github_copilot_executor_test.go b/internal/runtime/executor/github_copilot_executor_test.go
index 66d5ce92..d3ce194a 100644
--- a/internal/runtime/executor/github_copilot_executor_test.go
+++ b/internal/runtime/executor/github_copilot_executor_test.go
@@ -70,6 +70,13 @@ func TestUseGitHubCopilotResponsesEndpoint_CodexModel(t *testing.T) {
 	}
 }
 
+func TestUseGitHubCopilotResponsesEndpoint_RegistryResponsesOnlyModel(t *testing.T) {
+	t.Parallel()
+	if !useGitHubCopilotResponsesEndpoint(sdktranslator.FromString("openai"), "gpt-5.4") {
+		t.Fatal("expected responses-only registry model to use /responses")
+	}
+}
+
 func TestUseGitHubCopilotResponsesEndpoint_DefaultChat(t *testing.T) {
 	t.Parallel()
 	if useGitHubCopilotResponsesEndpoint(sdktranslator.FromString("openai"), "claude-3-5-sonnet") {