Preserve Codex template context defaults

Author: EricLi404

sdk/api/handlers/openai/codex_client_models.go

@@ -100,11 +100,6 @@ func loadCodexClientModelTemplates() (map[string]map[string]any, map[string]any,
 
 func applyCodexClientContextWindowOverride(entry map[string]any, id string, model map[string]any) {
 	contextWindow := intModelValue(model, "context_length")
-	if contextWindow <= 0 {
-		if info := registry.LookupModelInfo(id); info != nil {
-			contextWindow = info.ContextLength
-		}
-	}
 	if contextWindow <= 0 {
 		return
 	}
@@ -126,7 +121,7 @@ func applyCodexClientModelMetadata(entry map[string]any, id string, model map[st
 		if info.Description != "" {
 			description = info.Description
 		}
-		if info.ContextLength > 0 {
+		if info.ContextLength > 0 && contextWindow <= 0 {
 			contextWindow = info.ContextLength
 		}
 		if info.Type == registry.OpenAIImageModelType {

sdk/api/handlers/openai/codex_client_models_test.go

@@ -23,3 +23,40 @@ func TestBuildCodexClientModelsAppliesContextLengthToTemplateModel(t *testing.T)
 		t.Fatal("expected template metadata to be preserved")
 	}
 }
+
+func TestBuildCodexClientModelsLeavesTemplateContextUnchangedWithoutOverride(t *testing.T) {
+	models := buildCodexClientModels([]map[string]any{{
+		"id":       "gpt-5.4",
+		"object":   "model",
+		"owned_by": "heybox",
+	}})
+
+	if len(models) != 1 {
+		t.Fatalf("models len = %d, want 1", len(models))
+	}
+	if got := intModelValue(models[0], "context_window"); got != 272000 {
+		t.Fatalf("context_window = %d, want template default 272000", got)
+	}
+	if got := intModelValue(models[0], "max_context_window"); got != 1000000 {
+		t.Fatalf("max_context_window = %d, want template default 1000000", got)
+	}
+}
+
+func TestBuildCodexClientModelsPrefersModelContextLengthForCustomModel(t *testing.T) {
+	models := buildCodexClientModels([]map[string]any{{
+		"id":             "gpt-5.4-custom",
+		"object":         "model",
+		"owned_by":       "heybox",
+		"context_length": 700000,
+	}})
+
+	if len(models) != 1 {
+		t.Fatalf("models len = %d, want 1", len(models))
+	}
+	if got := intModelValue(models[0], "context_window"); got != 700000 {
+		t.Fatalf("context_window = %d, want 700000", got)
+	}
+	if got := intModelValue(models[0], "max_context_window"); got != 700000 {
+		t.Fatalf("max_context_window = %d, want 700000", got)
+	}
+}