diff --git a/internal/logic/relay/provider.go b/internal/logic/relay/provider.go
index 1d09a25..2d5c428 100644
--- a/internal/logic/relay/provider.go
+++ b/internal/logic/relay/provider.go
@@ -866,6 +866,12 @@ func InitHealthScore(ctx context.Context, channelID int64) error {
 // MaterializeSelection 由新调度引擎的决策构造 ChannelSelection（阶段 3）：
 // 转发元数据来自目录内存快照（零 DB），渠道 Key 按 keyID 解密（keyID=0 回退取首个 active Key）。
 func (p *DataProviderImpl) MaterializeSelection(ctx context.Context, channelID, keyID int64, modelName string) (*common.ChannelSelection, error) {
+	// 优先检查上下文：客户端已断开时直接返回 ctx.Err()，而非 ErrChannelUnavailable，
+	// 让上层能区分"客户端断开"与"真实渠道无可用 Key"，避免误伤渠道健康评分
+	if err := ctx.Err(); err != nil {
+		return nil, err
+	}
+
 	catalog := dispatchadapter.CatalogInstance()
 	if catalog == nil {
 		return nil, common.ErrChannelUnavailable
@@ -883,6 +889,10 @@ func (p *DataProviderImpl) MaterializeSelection(ctx context.Context, channelID,
 		apiKey, err = getChannelKey(ctx, channelID)
 	}
 	if err != nil || apiKey == "" {
+		// Key 查询失败：再次检查 ctx，区分"客户端断开导致查询中断"与"真实无可用 Key"
+		if ctxErr := ctx.Err(); ctxErr != nil {
+			return nil, ctxErr
+		}
 		return nil, common.ErrChannelUnavailable
 	}
 
diff --git a/relay/handler/relay_handler.go b/relay/handler/relay_handler.go
index 46fe81a..5aace7c 100644
--- a/relay/handler/relay_handler.go
+++ b/relay/handler/relay_handler.go
@@ -480,6 +480,14 @@ func RelayHandler(ctx context.Context, body []byte, path string, headers http.He
 
 		selection, mErr := provider.MaterializeSelection(ctx, d.Channel.ID, d.KeyID, v.lookupModel)
 		if mErr != nil {
+			// 客户端已断开（context.Canceled / DeadlineExceeded）：Key 查询被中断不代表渠道有问题，
+			// 静默退出，不记入 channelErrors，不触发渠道健康惩罚，退还预扣款项后返回
+			if errors.Is(mErr, context.Canceled) || errors.Is(mErr, context.DeadlineExceeded) {
+				if billing != nil && preDeductAmount > 0 {
+					_ = billing.SettleFailed(context.WithoutCancel(ctx), rc.TenantID, rc.RequestID, preDeductAmount)
+				}
+				return nil, v.billingResult, mErr
+			}
 			// Key 解密失败 / 目录元数据缺失：按渠道级致命上报换渠道，不发起上游请求
 			channelErrors = append(channelErrors, fmt.Sprintf("attempt=%d channel=%d materialize_error=[%v]", attempt, d.Channel.ID, mErr))
 			if decision := reportMaterializeFailure(ctx, sess, mErr); decision == dispatch.DecisionAbort {