diff --git a/internal/clienterror/client_error.go b/internal/clienterror/client_error.go
index 3a2f532d8..78565428d 100644
--- a/internal/clienterror/client_error.go
+++ b/internal/clienterror/client_error.go
@@ -80,6 +80,12 @@ func IsRequestFault(status int, err error) bool {
 			status = statusErr.StatusCode()
 		}
 	}
+	// HTTP 402 is a credential payment or balance failure. Some upstreams,
+	// including DeepSeek, label it with the generic invalid_request_error code.
+	// The status is authoritative so the credential can cool down and rotate.
+	if status == http.StatusPaymentRequired {
+		return false
+	}
 	if hasRequestFaultBody(err) {
 		return true
 	}
diff --git a/internal/clienterror/client_error_test.go b/internal/clienterror/client_error_test.go
index db17df399..7086230b6 100644
--- a/internal/clienterror/client_error_test.go
+++ b/internal/clienterror/client_error_test.go
@@ -191,6 +191,12 @@ func TestIsRequestFault(t *testing.T) {
 		},
 		{name: "plain not found", status: http.StatusNotFound, err: errors.New("model not found")},
 		{name: "unauthorized", status: http.StatusUnauthorized, err: errors.New("invalid token")},
+		{
+			name:   "deepseek insufficient balance is payment failure",
+			status: http.StatusPaymentRequired,
+			err:    errors.New(`{"error":{"message":"Insufficient Balance","type":"unknown_error","param":null,"code":"invalid_request_error"}}`),
+			want:   false,
+		},
 		{name: "quota", status: http.StatusTooManyRequests, err: errors.New("quota")},
 		{name: "transport", status: http.StatusBadGateway, err: errors.New("unexpected EOF")},
 		{name: "invalid JSON body", status: http.StatusBadGateway, err: errors.New(`{"error":`)},
diff --git a/sdk/cliproxy/auth/conductor_overrides_test.go b/sdk/cliproxy/auth/conductor_overrides_test.go
index de35ebc9a..96996ee53 100644
--- a/sdk/cliproxy/auth/conductor_overrides_test.go
+++ b/sdk/cliproxy/auth/conductor_overrides_test.go
@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"slices"
 	"sync"
 	"testing"
 	"time"
@@ -1353,6 +1354,99 @@ func TestManager_RequestScopedErrorStopsCredentialFallbackWithoutSuspendingAuth(
 	}
 }
 
+func TestManager_DeepSeekInsufficientBalanceRotatesCredentialAndRebindsSession(t *testing.T) {
+	m := NewManager(nil, nil, nil)
+	m.SetRetryConfig(2, 30*time.Second, 0)
+	affinity := NewSessionAffinitySelectorWithConfig(SessionAffinityConfig{
+		Fallback: &RoundRobinSelector{},
+		TTL:      time.Hour,
+	})
+	defer affinity.Stop()
+	m.SetSelector(affinity)
+
+	const provider = "openai-compatibility"
+	const model = "deepseek-v4-pro"
+
+	executor := &authFallbackExecutor{
+		id: provider,
+		executeErrors: map[string]error{
+			"aa-empty-balance": &Error{
+				HTTPStatus: http.StatusPaymentRequired,
+				Message:    `{"error":{"message":"Insufficient Balance","type":"unknown_error","param":null,"code":"invalid_request_error"}}`,
+			},
+		},
+	}
+	m.RegisterExecutor(executor)
+
+	depletedAuth := &Auth{ID: "aa-empty-balance", Provider: provider}
+	availableAuth := &Auth{ID: "bb-available-balance", Provider: provider}
+
+	reg := registry.GetGlobalRegistry()
+	models := []*registry.ModelInfo{{ID: model}}
+	reg.RegisterClient(depletedAuth.ID, provider, models)
+	reg.RegisterClient(availableAuth.ID, provider, models)
+	t.Cleanup(func() {
+		reg.UnregisterClient(depletedAuth.ID)
+		reg.UnregisterClient(availableAuth.ID)
+	})
+
+	if _, errRegister := m.Register(context.Background(), depletedAuth); errRegister != nil {
+		t.Fatalf("register depleted auth: %v", errRegister)
+	}
+	if _, errRegister := m.Register(context.Background(), availableAuth); errRegister != nil {
+		t.Fatalf("register available auth: %v", errRegister)
+	}
+
+	opts := cliproxyexecutor.Options{Metadata: map[string]any{
+		cliproxyexecutor.DerivedSessionIDMetadataKey: "deepseek-insufficient-balance",
+	}}
+	beforeExecute := time.Now()
+	resp, errExecute := m.Execute(
+		context.Background(),
+		[]string{provider},
+		cliproxyexecutor.Request{Model: model},
+		opts,
+	)
+	if errExecute != nil {
+		t.Fatalf("expected fallback to the next credential, got error: %v", errExecute)
+	}
+	if got := string(resp.Payload); got != availableAuth.ID {
+		t.Fatalf("served by %q, want %q", got, availableAuth.ID)
+	}
+
+	resp, errExecute = m.Execute(
+		context.Background(),
+		[]string{provider},
+		cliproxyexecutor.Request{Model: model},
+		opts,
+	)
+	if errExecute != nil {
+		t.Fatalf("expected rebound session to use the next credential, got error: %v", errExecute)
+	}
+	if got := string(resp.Payload); got != availableAuth.ID {
+		t.Fatalf("rebound session served by %q, want %q", got, availableAuth.ID)
+	}
+	wantCalls := []string{depletedAuth.ID, availableAuth.ID, availableAuth.ID}
+	if calls := executor.ExecuteCalls(); !slices.Equal(calls, wantCalls) {
+		t.Fatalf("credential calls = %v, want %v", calls, wantCalls)
+	}
+
+	updatedDepleted, ok := m.GetByID(depletedAuth.ID)
+	if !ok || updatedDepleted == nil {
+		t.Fatal("expected depleted auth to remain registered")
+	}
+	state := updatedDepleted.ModelStates[model]
+	if state == nil {
+		t.Fatal("expected the depleted credential to be cooled down for the model")
+	}
+	if !state.Unavailable {
+		t.Fatal("expected the depleted credential to be unavailable for the model")
+	}
+	if state.NextRetryAfter.Before(beforeExecute.Add(29 * time.Minute)) {
+		t.Fatalf("cooldown expires at %v, want approximately 30 minutes", state.NextRetryAfter)
+	}
+}
+
 // TestManager_UnknownUpstreamErrorRotatesAndPenalizesModelOnly pins the upstream
 // 500 "status":"UNKNOWN" contract. It is an upstream internal failure, not a
 // request fault, so the request must fall through to the next credential. The