diff --git a/d-engine-core/src/raft_role/leader_state.rs b/d-engine-core/src/raft_role/leader_state.rs
index 2fe9afed..b82c959b 100644
--- a/d-engine-core/src/raft_role/leader_state.rs
+++ b/d-engine-core/src/raft_role/leader_state.rs
@@ -3247,7 +3247,7 @@ impl<T: TypeConfig> LeaderState<T> {
         // Step 1: Remove stale entries (older than configured threshold)
         let now = Instant::now();
         self.pending_promotions.retain(|entry| {
-            now.duration_since(entry.ready_since) <= config.stale_learner_threshold
+            now.saturating_duration_since(entry.ready_since) <= config.stale_learner_threshold
         });
 
         if self.pending_promotions.is_empty() {
@@ -3661,10 +3661,11 @@ impl<T: TypeConfig> LeaderState<T> {
                 trace!(
                     "Inspecting entry: {:?} - {:?} - {:?}",
                     entry,
-                    now.duration_since(entry.ready_since),
+                    now.saturating_duration_since(entry.ready_since),
                     &config.stale_learner_threshold
                 );
-                if now.duration_since(entry.ready_since) > config.stale_learner_threshold {
+                if now.saturating_duration_since(entry.ready_since) > config.stale_learner_threshold
+                {
                     stale_entries.push(entry);
                 } else {
                     // Return non-stale entry and stop
diff --git a/d-engine-server/src/lib.rs b/d-engine-server/src/lib.rs
index ac7c8f08..0338d456 100644
--- a/d-engine-server/src/lib.rs
+++ b/d-engine-server/src/lib.rs
@@ -132,8 +132,11 @@ pub use d_engine_core::Result;
 pub use d_engine_core::SnapshotError;
 /// Storage-specific error type
 pub use d_engine_core::StorageError;
-// -------------------- Extension Traits --------------------
+// -------------------- Client API --------------------
 pub use api::EmbeddedClient;
+/// Unified client operations trait (put/get/delete/CAS/watch).
+/// Re-exported here so embedded-mode users don't need a separate d-engine-client dependency.
+pub use d_engine_core::client::{ClientApi, ClientApiError, ClientApiResult};
 /// Storage trait for implementing custom storage backends
 ///
 /// Implement this trait to create your own storage engine.