diff --git a/config.example.yaml b/config.example.yaml
index 1e3f1301..bd0b5460 100644
--- a/config.example.yaml
+++ b/config.example.yaml
@@ -510,14 +510,15 @@ nonstream-keepalive-interval: 0
 #       - "claude-3-*"               # wildcard matching prefix (e.g. claude-3-7-sonnet-20250219)
 #       - "*-thinking"               # wildcard matching suffix (e.g. claude-opus-4-5-thinking)
 #       - "*haiku*"                  # wildcard matching substring (e.g. claude-3-5-haiku-20241022)
-#     rebuild-mid-system-message: false # optional: default is false; when true, move messages with role "system" into the top-level Claude system field
+#     rebuild-mid-system-message: false # optional: default is false; when true, keep caller instructions in the top-level Claude system field, including after cloaking
 #     cloak:                         # optional: explicitly enable request cloaking for non-Claude-Code clients
 #       mode: "auto"                 # "auto" (default inside this block): cloak only when client is not Claude Code
 #                                    # "always": cloak every unconfirmed client; confirmed native Claude Code still passes through
 #                                    # "never": never apply cloaking
 #       # This "cloak" block applies to this claude-api-key entry only. For Claude OAuth
 #       # credentials, set the same options in the auth/token JSON file via "cloak_mode" /
-#       # "cloak_strict_mode" / "cloak_sensitive_words" / "cloak_cache_user_id". The top-level
+#       # "cloak_strict_mode" / "cloak_sensitive_words" / "cloak_cache_user_id". OAuth token
+#       # JSON also accepts "rebuild_mid_system_message": "true" for the option above. The top-level
 #       # "disable-claude-cloak-mode: true" disables cloaking for all Claude credentials at once.
 #       strict-mode: false           # false (default): legacy-model whitelist uses a user system-reminder;
 #                                    # all other and future models use messages[].role=system
diff --git a/internal/runtime/executor/claude_executor_execute.go b/internal/runtime/executor/claude_executor_execute.go
index 386a01d0..a91b5ed0 100644
--- a/internal/runtime/executor/claude_executor_execute.go
+++ b/internal/runtime/executor/claude_executor_execute.go
@@ -102,6 +102,12 @@ func (e *ClaudeExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, r
 	if err != nil {
 		return resp, err
 	}
+	// Cloaking may introduce role=system turns after the caller-requested rebuild
+	// ran. Apply the same policy to the finished cloaked layout so the option
+	// actually keeps stable instructions in the top-level system field.
+	if rebuildMidSystemMessageEnabled(e.cfg, auth) {
+		body = rebuildMidSystemMessagesToTopLevel(body)
+	}
 	systemPlacementState := captureClaudeCodeSystemPlacement(bodyBeforeCloaking, body, cloaked)
 	fableState := captureClaudeCodeFableState(bodyBeforeCloaking, body, cloaked)
 	// Only the Messages endpoint on Anthropic itself was captured; count_tokens
diff --git a/internal/runtime/executor/claude_executor_stream.go b/internal/runtime/executor/claude_executor_stream.go
index 7f9109f0..02e5d0d6 100644
--- a/internal/runtime/executor/claude_executor_stream.go
+++ b/internal/runtime/executor/claude_executor_stream.go
@@ -105,6 +105,12 @@ func (e *ClaudeExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.A
 	if err != nil {
 		return nil, err
 	}
+	// Cloaking may introduce role=system turns after the caller-requested rebuild
+	// ran. Apply the same policy to the finished cloaked layout so the option
+	// actually keeps stable instructions in the top-level system field.
+	if rebuildMidSystemMessageEnabled(e.cfg, auth) {
+		body = rebuildMidSystemMessagesToTopLevel(body)
+	}
 	systemPlacementState := captureClaudeCodeSystemPlacement(bodyBeforeCloaking, body, cloaked)
 	fableState := captureClaudeCodeFableState(bodyBeforeCloaking, body, cloaked)
 	// Only the Messages endpoint on Anthropic itself was captured; count_tokens
diff --git a/internal/runtime/executor/claude_executor_tokens.go b/internal/runtime/executor/claude_executor_tokens.go
index 58b0e4f7..c43b887a 100644
--- a/internal/runtime/executor/claude_executor_tokens.go
+++ b/internal/runtime/executor/claude_executor_tokens.go
@@ -169,6 +169,9 @@ func (e *ClaudeExecutor) countTokensUpstream(ctx context.Context, auth *cliproxy
 			}
 		}
 		body = relocateClaudeSystemPromptForCountTokens(body, settings.strictMode)
+		if rebuildMidSystemMessageEnabled(e.cfg, auth) {
+			body = rebuildMidSystemMessagesToTopLevel(body)
+		}
 		if len(settings.sensitiveWords) > 0 {
 			body = helps.ObfuscateSensitiveWords(body, helps.BuildSensitiveWordMatcher(settings.sensitiveWords))
 		}
diff --git a/internal/runtime/executor/claude_mid_system_model_test.go b/internal/runtime/executor/claude_mid_system_model_test.go
index 650c538f..65db8603 100644
--- a/internal/runtime/executor/claude_mid_system_model_test.go
+++ b/internal/runtime/executor/claude_mid_system_model_test.go
@@ -362,6 +362,78 @@ func TestClaudeExecutor_LegacyMidSystemMessageOptInStillRebuilds(t *testing.T) {
 	}
 }
 
+// OAuth credentials store per-credential options in token metadata. Cloaking
+// runs after the initial rebuild pass, so the option must also fold the system
+// turns introduced by cloaking back into the top-level system field.
+func TestClaudeExecutor_OAuthRebuildKeepsCloakedInstructionsTopLevel(t *testing.T) {
+	tests := []struct {
+		name string
+		send func(t *testing.T, ex *ClaudeExecutor, ctx context.Context, auth *cliproxyauth.Auth, payload []byte) error
+	}{
+		{
+			name: "execute",
+			send: func(t *testing.T, ex *ClaudeExecutor, ctx context.Context, auth *cliproxyauth.Auth, payload []byte) error {
+				_, err := ex.Execute(ctx, auth, cliproxyexecutor.Request{Model: "claude-opus-5", Payload: payload},
+					cliproxyexecutor.Options{SourceFormat: sdktranslator.FormatClaude})
+				return err
+			},
+		},
+		{
+			name: "execute stream",
+			send: func(t *testing.T, ex *ClaudeExecutor, ctx context.Context, auth *cliproxyauth.Auth, payload []byte) error {
+				result, err := ex.ExecuteStream(ctx, auth, cliproxyexecutor.Request{Model: "claude-opus-5", Payload: payload},
+					cliproxyexecutor.Options{SourceFormat: sdktranslator.FormatClaude})
+				if err != nil {
+					return err
+				}
+				for chunk := range result.Chunks {
+					if chunk.Err != nil {
+						return chunk.Err
+					}
+				}
+				return nil
+			},
+		},
+		{
+			name: "count tokens",
+			send: func(t *testing.T, ex *ClaudeExecutor, ctx context.Context, auth *cliproxyauth.Auth, payload []byte) error {
+				_, err := ex.CountTokens(ctx, auth, cliproxyexecutor.Request{Model: "claude-opus-5", Payload: payload},
+					cliproxyexecutor.Options{SourceFormat: sdktranslator.FormatClaude})
+				return err
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			upstream := &midSystemUpstream{}
+			auth := midSystemAuth()
+			auth.Metadata = map[string]any{"rebuild_mid_system_message": "true"}
+			payload := []byte(`{"model":"claude-opus-5","max_tokens":32,` +
+				`"system":[{"type":"text","text":"Stable caller rule"}],` +
+				`"messages":[{"role":"user","content":[{"type":"text","text":"hi"}]}]}`)
+
+			if err := test.send(t, NewClaudeExecutor(midSystemConfig()), upstream.context(t, nil), auth, payload); err != nil {
+				t.Fatalf("request error = %v", err)
+			}
+			if !upstream.called {
+				t.Fatal("expected request to reach upstream")
+			}
+			if gjson.GetBytes(upstream.body, `messages.#(role=="system")`).Exists() {
+				t.Fatalf("cloaked instructions were reinserted into messages: %s", upstream.body)
+			}
+			foundRule := false
+			gjson.GetBytes(upstream.body, "system").ForEach(func(_, block gjson.Result) bool {
+				foundRule = foundRule || block.Get("text").String() == "Stable caller rule"
+				return true
+			})
+			if !foundRule {
+				t.Fatalf("caller instruction missing from top-level system: %s", upstream.body)
+			}
+		})
+	}
+}
+
 // The pairing must never originate inside CPA. A non-Claude caller reaches the
 // Claude executor through a translator, and every translator hoists system
 // content into the top-level system field, so no translated body can carry a
diff --git a/internal/runtime/executor/claude_signing.go b/internal/runtime/executor/claude_signing.go
index 5642bcbe..f7c2ef45 100644
--- a/internal/runtime/executor/claude_signing.go
+++ b/internal/runtime/executor/claude_signing.go
@@ -9,6 +9,7 @@ import (
 	"strings"
 
 	xxHash64 "github.com/pierrec/xxHash/xxHash64"
+	claudeauth "github.com/router-for-me/CLIProxyAPI/v7/internal/auth/claude"
 	"github.com/router-for-me/CLIProxyAPI/v7/internal/config"
 	"github.com/router-for-me/CLIProxyAPI/v7/internal/util"
 	cliproxyauth "github.com/router-for-me/CLIProxyAPI/v7/sdk/cliproxy/auth"
@@ -546,6 +547,9 @@ func rebuildMidSystemMessageEnabled(cfg *config.Config, auth *cliproxyauth.Auth)
 	if auth != nil && auth.Attributes != nil && strings.EqualFold(strings.TrimSpace(auth.Attributes["rebuild_mid_system_message"]), "true") {
 		return true
 	}
+	if auth != nil && strings.EqualFold(strings.TrimSpace(claudeauth.ReadMetadataString(&auth.Metadata, "rebuild_mid_system_message")), "true") {
+		return true
+	}
 	entry := resolveClaudeKeyConfig(cfg, auth)
 	return entry != nil && entry.RebuildMidSystemMessage
 }