diff --git a/backend/internal/handler/openai_codex_models_handler_test.go b/backend/internal/handler/openai_codex_models_handler_test.go
index ea31545631..5d102cfbf9 100644
--- a/backend/internal/handler/openai_codex_models_handler_test.go
+++ b/backend/internal/handler/openai_codex_models_handler_test.go
@@ -1001,3 +1001,32 @@ func TestCodexModelsPinnedAccountsETagMatchReturns304(t *testing.T) {
 	require.Equal(t, http.StatusNotModified, second.Code, second.Body.String())
 	require.Empty(t, second.Body.Bytes())
 }
+
+func TestCodexModelsDiscoveryProjectsWildcardMappingWithoutAllowlist(t *testing.T) {
+	for _, mode := range []string{"ordinary", "pinned", "fallback"} {
+		t.Run(mode, func(t *testing.T) {
+			account := newPinnedCodexAccount(1, service.StatusActive, true, false)
+			account.Credentials["model_mapping"] = map[string]any{"gpt-*": "gpt-5.4"}
+			upstream := &codexModelsPinnedHTTPUpstream{bodies: map[int64]string{
+				1: `{"models":[{"slug":"gpt-5.4"},{"slug":"blocked"},{"slug":"codex-auto-review"},{"slug":"gpt-image-2"}]}`,
+			}}
+			handler := newPinnedCodexTestHandler([]service.Account{account}, upstream, 3)
+			group := &service.Group{ID: 84, Platform: service.PlatformOpenAI,
+				ModelAllowlist: service.GroupModelAllowlist{Models: []string{"blocked"}},
+			}
+			if mode != "ordinary" {
+				group.CodexModelsManifestConfig = service.GroupCodexModelsManifestConfig{Enabled: true, AccountIDs: []int64{1}}
+			}
+			if mode == "fallback" {
+				group.CodexModelsManifestConfig.AccountIDs = []int64{999}
+				group.CodexModelsManifestConfig.FallbackToScheduler = true
+			}
+			first := performCodexModelsRequestForGroup(t, handler, group, "")
+			require.Equal(t, http.StatusOK, first.Code, first.Body.String())
+			require.Equal(t, []string{"gpt-5.4"}, codexHandlerManifestSlugs(t, first))
+			require.NotEmpty(t, first.Header().Get("ETag"))
+			second := performCodexModelsRequestForGroup(t, handler, group, first.Header().Get("ETag"))
+			require.Equal(t, http.StatusNotModified, second.Code)
+		})
+	}
+}
diff --git a/backend/internal/service/openai_codex_models_pinned.go b/backend/internal/service/openai_codex_models_pinned.go
index b74b3eafdc..16faefd068 100644
--- a/backend/internal/service/openai_codex_models_pinned.go
+++ b/backend/internal/service/openai_codex_models_pinned.go
@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"log/slog"
 	"net/http"
+	"slices"
 	"strings"
 	"sync"
 	"time"
@@ -91,6 +92,13 @@ func mergeCodexModelsManifestBodies(bodies [][]byte) ([]byte, error) {
 		}
 	}
 
+	if len(bodies) == 1 {
+		_, original, err := modelCatalogEntries(bodies[0], "models")
+		if err == nil && slices.EqualFunc(original, mergedModels, func(a, b json.RawMessage) bool { return bytes.Equal(a, b) }) {
+			return bodies[0], nil
+		}
+	}
+
 	encodedModels, err := json.Marshal(mergedModels)
 	if err != nil {
 		return nil, fmt.Errorf("encode merged codex models: %w", err)
@@ -139,6 +147,9 @@ func (s *OpenAIGatewayService) FetchPinnedCodexModelsManifest(ctx context.Contex
 	if err != nil {
 		return nil, nil, fmt.Errorf("merge pinned codex models manifests: %w", err)
 	}
+	if len(results) == 1 && bytes.Equal(merged, results[0].response.Body) {
+		return results[0].response, results[0].account, nil
+	}
 	return &OpenAIModelsResponse{Body: merged, ETag: codexModelsManifestBodyETag(merged)}, results[0].account, nil
 }
 
diff --git a/backend/internal/service/openai_codex_models_pinned_test.go b/backend/internal/service/openai_codex_models_pinned_test.go
index eee3100c76..3c389402f4 100644
--- a/backend/internal/service/openai_codex_models_pinned_test.go
+++ b/backend/internal/service/openai_codex_models_pinned_test.go
@@ -63,11 +63,11 @@ func TestMergeCodexModelsManifestBodiesHandlesSluglessEntries(t *testing.T) {
 }
 
 func TestMergeCodexModelsManifestBodiesSingleBody(t *testing.T) {
-	body := `{"models":[{"slug":"model-a"}]}`
+	body := `{ "unknown": true, "models": [ { "slug": "model-a" } ] }`
 
 	merged, err := mergeCodexModelsManifestBodies([][]byte{[]byte(body)})
 	require.NoError(t, err)
-	require.JSONEq(t, body, string(merged))
+	require.Equal(t, body, string(merged))
 }
 
 func TestMergeCodexModelsManifestBodiesRejectsInvalidInput(t *testing.T) {
@@ -80,3 +80,9 @@ func TestMergeCodexModelsManifestBodiesRejectsInvalidInput(t *testing.T) {
 	_, err = mergeCodexModelsManifestBodies([][]byte{[]byte(`{}`), []byte(`{"models":{}`)})
 	require.Error(t, err, "models 非数组必须报错")
 }
+
+func TestMergeCodexModelsManifestBodiesSingleBodyDeduplicates(t *testing.T) {
+	merged, err := mergeCodexModelsManifestBodies([][]byte{[]byte(`{"models":[{"slug":"a"},{"slug":"a","extra":true}]}`)})
+	require.NoError(t, err)
+	require.JSONEq(t, `{"models":[{"slug":"a"}]}`, string(merged))
+}
diff --git a/backend/internal/service/openai_models_list.go b/backend/internal/service/openai_models_list.go
index 2a07f10d67..9b27a03cd4 100644
--- a/backend/internal/service/openai_models_list.go
+++ b/backend/internal/service/openai_models_list.go
@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
+	"slices"
 	"sort"
 	"strings"
 
@@ -229,6 +230,10 @@ func projectAccountModelsBody(body []byte, account *Account, group *Group, codex
 			continue
 		}
 		seen[id] = struct{}{}
+		if id == target {
+			projected = append(projected, raw)
+			continue
+		}
 		var entry map[string]json.RawMessage
 		if err := json.Unmarshal(raw, &entry); err != nil {
 			return nil, err
@@ -243,6 +248,9 @@ func projectAccountModelsBody(body []byte, account *Account, group *Group, codex
 		}
 		projected = append(projected, encoded)
 	}
+	if slices.EqualFunc(entries, projected, func(a, b json.RawMessage) bool { return bytes.Equal(a, b) }) {
+		return body, nil
+	}
 	envelope[field], err = json.Marshal(projected)
 	if err != nil {
 		return nil, err
@@ -250,18 +258,21 @@ func projectAccountModelsBody(body []byte, account *Account, group *Group, codex
 	return json.Marshal(envelope)
 }
 
-// ApplyPinnedCodexModelsMapping is used by pinned discovery and its scheduler
-// fallback. The ordinary (non-pinned) Codex path retains its local catalog policy.
+// ApplyPinnedCodexModelsMapping projects all remotely discovered Codex catalogs,
+// including ordinary discovery and pinned scheduler fallback. Locally generated
+// catalogs retain their existing policy and do not pass through this function.
 func ApplyPinnedCodexModelsMapping(response *OpenAIModelsResponse, account *Account, group *Group) error {
-	if group == nil || group.Platform != PlatformOpenAI || !group.CodexModelsManifestConfig.Enabled {
+	if group == nil || group.Platform != PlatformOpenAI {
 		return nil
 	}
 	body, err := projectAccountModelsBody(response.Body, account, group, true)
 	if err != nil {
 		return err
 	}
-	response.Body = body
-	response.ETag = codexModelsManifestBodyETag(body)
+	if !bytes.Equal(response.Body, body) {
+		response.Body = body
+		response.ETag = codexModelsManifestBodyETag(body)
+	}
 	return nil
 }
 
diff --git a/backend/internal/service/openai_models_list_test.go b/backend/internal/service/openai_models_list_test.go
index 08df6e249c..edb50a569e 100644
--- a/backend/internal/service/openai_models_list_test.go
+++ b/backend/internal/service/openai_models_list_test.go
@@ -3,6 +3,7 @@ package service
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"io"
 	"net/http"
 	"strings"
@@ -346,3 +347,18 @@ func TestOpenAIModelsCacheSeparatesRepresentationsForIdenticalRequests(t *testin
 	require.JSONEq(t, manifestBody, string(manifest.Body))
 	require.EqualValues(t, 2, calls.Load())
 }
+
+func TestApplyCodexModelsMappingPreservesUnchangedBodyAndETag(t *testing.T) {
+	for _, pinned := range []bool{false, true} {
+		t.Run(fmt.Sprint(pinned), func(t *testing.T) {
+			account := newCodexModelsAPIKeyTestAccount("https://models.example/v1")
+			account.Credentials["model_mapping"] = map[string]any{"gpt-5.4": "gpt-5.4"}
+			body := []byte(`{ "unknown": { "keep": true }, "models": [ { "slug": "gpt-5.4", "custom": 123 } ] }`)
+			response := &OpenAIModelsResponse{Body: body, ETag: `W/"upstream-validator"`}
+			group := &Group{Platform: PlatformOpenAI, CodexModelsManifestConfig: GroupCodexModelsManifestConfig{Enabled: pinned}}
+			require.NoError(t, ApplyPinnedCodexModelsMapping(response, account, group))
+			require.Equal(t, body, response.Body)
+			require.Equal(t, `W/"upstream-validator"`, response.ETag)
+		})
+	}
+}