diff --git a/bin/fxt/src/tui/data_fetcher.rs b/bin/fxt/src/tui/data_fetcher.rs
index f19665421..61b9dffc0 100644
--- a/bin/fxt/src/tui/data_fetcher.rs
+++ b/bin/fxt/src/tui/data_fetcher.rs
@@ -29,6 +29,9 @@ use super::state::{
     RiskAlertData, RiskData, ServiceData, SystemResources, TrainingSessionData,
 };
 
+/// Empty filter string means "fetch all" in gRPC requests.
+const FILTER_ALL: &str = "";
+
 // ---------------------------------------------------------------------------
 // StateUpdate – one variant per data source
 // ---------------------------------------------------------------------------
@@ -143,7 +146,7 @@ impl DataFetcher {
             let mut backoff = Backoff::new();
             loop {
                 let req = Request::new(monitoring::StreamTrainingMetricsRequest {
-                    model_filter: String::new(),
+                    model_filter: FILTER_ALL.into(),
                     interval_seconds: 3,
                 });
                 match mon.stream_training_metrics(req).await {
@@ -420,7 +423,7 @@ impl DataFetcher {
             let mut backoff = Backoff::new();
             loop {
                 let req = Request::new(trading::StreamPortfolioSummaryRequest {
-                    account_id: String::new(),
+                    account_id: FILTER_ALL.into(),
                     interval_seconds: 3,
                 });
                 match trd.stream_portfolio_summary(req).await {
@@ -716,7 +719,7 @@ impl DataFetcher {
             let mut backoff = Backoff::new();
             loop {
                 let req = Request::new(ml::StreamModelStatusRequest {
-                    model_name: String::new(), // all models
+                    model_name: FILTER_ALL.into(), // all models
                     interval_seconds: 5,
                 });
                 match ml_client.stream_model_status(req).await {