diff --git a/backend/internal/service/openai_codex_model_metadata_test.go b/backend/internal/service/openai_codex_model_metadata_test.go
index cb757a1faa..f0d35b56ce 100644
--- a/backend/internal/service/openai_codex_model_metadata_test.go
+++ b/backend/internal/service/openai_codex_model_metadata_test.go
@@ -192,6 +192,79 @@ func TestBuildCodexModelsManifestForGroupUsesSyncedAccountMetadata(t *testing.T)
 	require.EqualValues(t, 1_000_000, models[0]["context_window"])
 }
 
+type openCodeGoCodexCatalogRepo struct {
+	AccountRepository
+	groupID   int64
+	accounts  []Account
+	platforms []string
+}
+
+func (r *openCodeGoCodexCatalogRepo) ListSchedulableByGroupID(_ context.Context, _ int64) ([]Account, error) {
+	return nil, nil
+}
+
+func (r *openCodeGoCodexCatalogRepo) ListModelAvailabilityCandidates(_ context.Context, groupID *int64, platforms []string, _ bool) ([]Account, error) {
+	r.platforms = append([]string(nil), platforms...)
+	if groupID == nil || *groupID != r.groupID {
+		return nil, nil
+	}
+	for _, platform := range platforms {
+		if platform == PlatformOpenCodeGo {
+			return append([]Account(nil), r.accounts...), nil
+		}
+	}
+	return nil, nil
+}
+
+// Scenario: OpenCode Go accounts contribute synced capabilities to a Composite
+// manifest only when they are selected by the catalog candidate query.
+func TestBuildCodexModelsManifestForGroupMergesOpenCodeGoSyncedMetadata(t *testing.T) {
+	t.Parallel()
+
+	const groupID int64 = 742
+	const publicModel = "oc/muse-spark-1.3-contributor"
+	const upstreamModel = "muse-spark-1.3-contributor"
+
+	reasoning := true
+	account := Account{
+		ID:       43,
+		Platform: PlatformOpenCodeGo,
+		Type:     AccountTypeAPIKey,
+		Credentials: map[string]any{
+			"base_url":      "https://opencode.ai/zen/go/v1",
+			"model_mapping": map[string]any{publicModel: upstreamModel},
+		},
+	}
+	account.SetUpstreamModelMetadataSnapshot(UpstreamModelMetadataSnapshot{Models: map[string]UpstreamModelMetadata{
+		upstreamModel: {
+			ID:                       upstreamModel,
+			Reasoning:                &reasoning,
+			DefaultReasoningLevel:    "medium",
+			SupportedReasoningLevels: []string{"minimal", "low", "medium", "high", "xhigh"},
+			InputModalities:          []string{"text", "image"},
+			ContextWindow:            1_048_576,
+		},
+	}})
+	repo := &openCodeGoCodexCatalogRepo{groupID: groupID, accounts: []Account{account}}
+	svc := &GatewayService{accountRepo: repo}
+
+	body, err := svc.BuildCodexModelsManifestForGroup(
+		context.Background(),
+		&Group{ID: groupID, Platform: PlatformComposite},
+		"",
+		[]string{publicModel},
+	)
+	require.NoError(t, err)
+	require.Contains(t, repo.platforms, PlatformOpenCodeGo)
+
+	models := decodeCodexManifestModels(t, body)
+	require.Len(t, models, 1)
+	require.Equal(t, []any{"text", "image"}, models[0]["input_modalities"])
+	require.Equal(t, "medium", models[0]["default_reasoning_level"])
+	require.Equal(t, []string{"minimal", "low", "medium", "high", "xhigh"}, effortsFromManifestModel(t, models[0]))
+	require.EqualValues(t, 1_048_576, models[0]["context_window"])
+}
+
 // Scenario: an explicitly non-reasoning model remains directly selectable in Codex.
 func TestBuildCodexModelsManifestForGroupUsesNoneForExplicitNonReasoningMetadata(t *testing.T) {
 	t.Parallel()
diff --git a/backend/internal/service/openai_codex_models_service.go b/backend/internal/service/openai_codex_models_service.go
index e2658581e7..008b41b86e 100644
--- a/backend/internal/service/openai_codex_models_service.go
+++ b/backend/internal/service/openai_codex_models_service.go
@@ -262,6 +262,7 @@ func loadCodexGroupCatalogAccounts(ctx context.Context, repo AccountRepository,
 			PlatformZhipu,
 			PlatformDeepseek,
 			PlatformMiniMax,
+			PlatformOpenCodeGo,
 		},
 		false,
 	)
@@ -1074,7 +1075,7 @@ func groupCodexModelSupportsImageInput(
 			return false
 		}
 	}
-	if platform != PlatformOpenAI && platform != PlatformGrok && platform != PlatformDeepseek {
+	if platform != PlatformOpenAI && platform != PlatformGrok && platform != PlatformDeepseek && platform != PlatformOpenCodeGo {
 		return false
 	}
 
@@ -1213,7 +1214,7 @@ func accountCodexModelSupportsImageInput(account *Account, upstreamModel string)
 		return false
 	}
 	switch account.Platform {
-	case PlatformOpenAI, PlatformDeepseek:
+	case PlatformOpenAI, PlatformDeepseek, PlatformOpenCodeGo:
 		if metadata, ok := account.GetUpstreamModelMetadata(upstreamModel); ok {
 			if modalities := normalizeCodexInputModalities(metadata.InputModalities); len(modalities) > 0 {
 				// Official GPT-6 Astra metadata briefly shipped with a stale
diff --git a/backend/internal/service/openai_codex_models_service_test.go b/backend/internal/service/openai_codex_models_service_test.go
index 888a32f55c..ae0d1f0396 100644
--- a/backend/internal/service/openai_codex_models_service_test.go
+++ b/backend/internal/service/openai_codex_models_service_test.go
@@ -1114,6 +1114,7 @@ func TestBuildCodexModelsManifestForGroupLoadsAccountsOnce(t *testing.T) {
 	require.Contains(t, repo.platforms, PlatformGrok)
 	require.Contains(t, repo.platforms, PlatformDeepseek)
 	require.Contains(t, repo.platforms, PlatformMiniMax)
+	require.Contains(t, repo.platforms, PlatformOpenCodeGo)
 	require.NotContains(t, repo.platforms, PlatformComposite)
 }