diff --git a/crates/openshell-cli/src/run.rs b/crates/openshell-cli/src/run.rs
index bab81913..98e110d8 100644
--- a/crates/openshell-cli/src/run.rs
+++ b/crates/openshell-cli/src/run.rs
@@ -2045,7 +2045,16 @@ pub async fn sandbox_create(
         name: name.unwrap_or_default().to_string(),
     };
 
-    let response = client.create_sandbox(request).await.into_diagnostic()?;
+    let response = match client.create_sandbox(request).await {
+        Ok(resp) => resp,
+        Err(status) if status.code() == Code::AlreadyExists => {
+            return Err(miette::miette!(
+                "{}\n\nhint: delete it first with: openshell sandbox delete <name>\n      or use a different name",
+                status.message()
+            ));
+        }
+        Err(status) => return Err(status).into_diagnostic(),
+    };
     let sandbox = response
         .into_inner()
         .sandbox
diff --git a/crates/openshell-server/src/grpc.rs b/crates/openshell-server/src/grpc.rs
index fd4bf585..911d2f09 100644
--- a/crates/openshell-server/src/grpc.rs
+++ b/crates/openshell-server/src/grpc.rs
@@ -244,6 +244,20 @@ impl OpenShell for OpenShellService {
             ..Default::default()
         };
 
+        // Reject duplicate names early, before touching the index or store.
+        // This mirrors the provider-creation pattern (see `create_provider`).
+        let existing = self
+            .state
+            .store
+            .get_message_by_name::<Sandbox>(&name)
+            .await
+            .map_err(|e| Status::internal(format!("fetch sandbox failed: {e}")))?;
+        if existing.is_some() {
+            return Err(Status::already_exists(format!(
+                "sandbox '{name}' already exists"
+            )));
+        }
+
         // Persist to the store FIRST so the sandbox watcher always finds
         // the record with `spec` populated.  If we created the k8s
         // resource first, the watcher could race us and write a fallback
diff --git a/e2e/python/test_inference_routing.py b/e2e/python/test_inference_routing.py
index bda0d8cb..c35e0253 100644
--- a/e2e/python/test_inference_routing.py
+++ b/e2e/python/test_inference_routing.py
@@ -95,11 +95,6 @@ def _upsert_managed_inference(
             except grpc.RpcError as create_exc:
                 if create_exc.code() == grpc.StatusCode.ALREADY_EXISTS:
                     continue
-                if (
-                    create_exc.code() == grpc.StatusCode.INTERNAL
-                    and "UNIQUE constraint failed" in (create_exc.details() or "")
-                ):
-                    continue
                 raise
     else:
         raise RuntimeError("failed to upsert managed e2e provider after retries")