diff --git a/crates/openshell-server/src/grpc.rs b/crates/openshell-server/src/grpc.rs
index a2c6a58f..268a692b 100644
--- a/crates/openshell-server/src/grpc.rs
+++ b/crates/openshell-server/src/grpc.rs
@@ -32,7 +32,7 @@ use openshell_core::proto::{
     WatchSandboxRequest, open_shell_server::OpenShell,
 };
 use openshell_core::proto::{
-    Sandbox, SandboxPhase, SandboxPolicy as ProtoSandboxPolicy, SandboxTemplate,
+    InferenceRoute, Sandbox, SandboxPhase, SandboxPolicy as ProtoSandboxPolicy, SandboxTemplate,
 };
 use prost::Message;
 use sha2::{Digest, Sha256};
@@ -3290,6 +3290,73 @@ async fn delete_provider_record(
         return Err(Status::invalid_argument("name is required"));
     }
 
+    // Early-out: if the provider doesn't exist, nothing to delete.
+    let exists = store
+        .get_by_name(Provider::object_type(), name)
+        .await
+        .map_err(|e| Status::internal(format!("check provider failed: {e}")))?;
+    if exists.is_none() {
+        return Ok(false);
+    }
+
+    // Check if any sandbox references this provider.
+    let sandbox_records = store
+        .list(Sandbox::object_type(), u32::MAX, 0)
+        .await
+        .map_err(|e| Status::internal(format!("list sandboxes failed: {e}")))?;
+
+    let mut referencing_sandboxes: Vec<String> = Vec::new();
+    for record in sandbox_records {
+        let sandbox = Sandbox::decode(record.payload.as_slice())
+            .map_err(|e| Status::internal(format!("decode sandbox failed: {e}")))?;
+        // Skip sandboxes that are already being deleted.
+        if sandbox.phase == SandboxPhase::Deleting as i32 {
+            continue;
+        }
+        if let Some(spec) = &sandbox.spec {
+            if spec.providers.iter().any(|p| p == name) {
+                referencing_sandboxes.push(sandbox.name.clone());
+            }
+        }
+    }
+
+    // Check if any inference route references this provider.
+    let mut referencing_routes: Vec<String> = Vec::new();
+    for route_name in ["inference.local", "sandbox-system"] {
+        if let Some(route) = store
+            .get_message_by_name::<InferenceRoute>(route_name)
+            .await
+            .map_err(|e| Status::internal(format!("fetch inference route failed: {e}")))?
+        {
+            if route
+                .config
+                .as_ref()
+                .is_some_and(|c| c.provider_name == name)
+            {
+                referencing_routes.push(route_name.to_string());
+            }
+        }
+    }
+
+    if !referencing_sandboxes.is_empty() || !referencing_routes.is_empty() {
+        let mut details = Vec::new();
+        if !referencing_sandboxes.is_empty() {
+            details.push(format!("sandbox(es): {}", referencing_sandboxes.join(", ")));
+        }
+        if !referencing_routes.is_empty() {
+            details.push(format!(
+                "inference route(s): {}",
+                referencing_routes.join(", ")
+            ));
+        }
+        return Err(Status::failed_precondition(format!(
+            "cannot delete provider '{}': still referenced by {}. \
+             Remove or update these references before deleting the provider.",
+            name,
+            details.join(" and ")
+        )));
+    }
+
     store
         .delete_by_name(Provider::object_type(), name)
         .await
@@ -3326,7 +3393,10 @@ mod tests {
         validate_provider_fields, validate_sandbox_spec,
     };
     use crate::persistence::Store;
-    use openshell_core::proto::{Provider, SandboxSpec, SandboxTemplate};
+    use openshell_core::proto::{
+        ClusterInferenceConfig, InferenceRoute, Provider, Sandbox, SandboxPhase, SandboxSpec,
+        SandboxTemplate,
+    };
     use std::collections::HashMap;
     use tonic::Code;
 
@@ -4624,4 +4694,129 @@ mod tests {
         assert_eq!(err.code(), Code::InvalidArgument);
         assert!(err.message().contains("value"));
     }
+
+    #[tokio::test]
+    async fn delete_provider_blocked_by_sandbox_reference() {
+        let store = Store::connect("sqlite::memory:?cache=shared")
+            .await
+            .unwrap();
+
+        let provider =
+            create_provider_record(&store, provider_with_values("my-provider", "nvidia"))
+                .await
+                .unwrap();
+
+        // Create a sandbox that references the provider.
+        let sandbox = Sandbox {
+            id: uuid::Uuid::new_v4().to_string(),
+            name: "test-sandbox".to_string(),
+            spec: Some(SandboxSpec {
+                providers: vec!["my-provider".to_string()],
+                ..SandboxSpec::default()
+            }),
+            ..Sandbox::default()
+        };
+        store.put_message(&sandbox).await.unwrap();
+
+        // Deleting the referenced provider should fail.
+        let err = delete_provider_record(&store, &provider.name)
+            .await
+            .unwrap_err();
+        assert_eq!(err.code(), Code::FailedPrecondition);
+        assert!(err.message().contains("test-sandbox"));
+        assert!(err.message().contains("my-provider"));
+    }
+
+    #[tokio::test]
+    async fn delete_provider_blocked_by_inference_route() {
+        let store = Store::connect("sqlite::memory:?cache=shared")
+            .await
+            .unwrap();
+
+        let provider =
+            create_provider_record(&store, provider_with_values("inference-provider", "nvidia"))
+                .await
+                .unwrap();
+
+        // Create an inference route that references the provider.
+        let route = InferenceRoute {
+            id: uuid::Uuid::new_v4().to_string(),
+            name: "inference.local".to_string(),
+            config: Some(ClusterInferenceConfig {
+                provider_name: "inference-provider".to_string(),
+                ..ClusterInferenceConfig::default()
+            }),
+            version: 1,
+        };
+        store.put_message(&route).await.unwrap();
+
+        // Deleting the referenced provider should fail.
+        let err = delete_provider_record(&store, &provider.name)
+            .await
+            .unwrap_err();
+        assert_eq!(err.code(), Code::FailedPrecondition);
+        assert!(err.message().contains("inference.local"));
+        assert!(err.message().contains("inference-provider"));
+    }
+
+    #[tokio::test]
+    async fn delete_provider_succeeds_when_unreferenced() {
+        let store = Store::connect("sqlite::memory:?cache=shared")
+            .await
+            .unwrap();
+
+        let provider =
+            create_provider_record(&store, provider_with_values("lonely-provider", "nvidia"))
+                .await
+                .unwrap();
+
+        // Create a sandbox that references a DIFFERENT provider name.
+        let sandbox = Sandbox {
+            id: uuid::Uuid::new_v4().to_string(),
+            name: "other-sandbox".to_string(),
+            spec: Some(SandboxSpec {
+                providers: vec!["other-provider".to_string()],
+                ..SandboxSpec::default()
+            }),
+            ..Sandbox::default()
+        };
+        store.put_message(&sandbox).await.unwrap();
+
+        // Deleting the unreferenced provider should succeed.
+        let deleted = delete_provider_record(&store, &provider.name)
+            .await
+            .unwrap();
+        assert!(deleted);
+    }
+
+    #[tokio::test]
+    async fn delete_provider_ignores_deleting_sandboxes() {
+        let store = Store::connect("sqlite::memory:?cache=shared")
+            .await
+            .unwrap();
+
+        let provider =
+            create_provider_record(&store, provider_with_values("my-provider", "nvidia"))
+                .await
+                .unwrap();
+
+        // Create a sandbox that references the provider but is already being deleted.
+        let sandbox = Sandbox {
+            id: uuid::Uuid::new_v4().to_string(),
+            name: "dying-sandbox".to_string(),
+            phase: SandboxPhase::Deleting as i32,
+            spec: Some(SandboxSpec {
+                providers: vec!["my-provider".to_string()],
+                ..SandboxSpec::default()
+            }),
+            ..Sandbox::default()
+        };
+        store.put_message(&sandbox).await.unwrap();
+
+        // Deleting sandboxes should not block provider deletion.
+        let deleted = delete_provider_record(&store, &provider.name)
+            .await
+            .unwrap();
+        assert!(deleted);
+    }
 }