diff --git a/crates/rollup/src/cli.rs b/crates/rollup/src/cli.rs
index 6e60172..0989942 100644
--- a/crates/rollup/src/cli.rs
+++ b/crates/rollup/src/cli.rs
@@ -16,9 +16,6 @@ pub const DEFAULT_L2_CHAIN_ID: u64 = 10;
 /// The default L1 RPC URL to use.
 pub const DEFAULT_L1_RPC_URL: &str = "https://cloudflare-eth.com";
 
-/// The default L2 RPC URL to use.
-pub const DEFAULT_L2_RPC_URL: &str = "https://optimism.llamarpc.com/";
-
 /// The default L1 Beacon Client RPC URL to use.
 pub const DEFAULT_L1_BEACON_CLIENT_URL: &str = "http://localhost:5052/";
 
@@ -34,10 +31,6 @@ pub struct HeraArgsExt {
     #[clap(long = "hera.l2-config-file")]
     pub l2_config_file: Option<PathBuf>,
 
-    /// RPC URL of an L2 execution client
-    #[clap(long = "hera.l2-rpc-url", default_value = DEFAULT_L2_RPC_URL)]
-    pub l2_rpc_url: Url,
-
     /// RPC URL of an L1 execution client
     /// (This is only needed when running in Standalone mode)
     #[clap(long = "hera.l1-rpc-url", default_value = DEFAULT_L1_RPC_URL)]
diff --git a/crates/rollup/src/engine/controller.rs b/crates/rollup/src/engine/controller.rs
new file mode 100644
index 0000000..b3ad983
--- /dev/null
+++ b/crates/rollup/src/engine/controller.rs
@@ -0,0 +1,20 @@
+//! The engine controller keeps the state of the engine.
+
+use op_alloy_protocol::L2BlockInfo;
+
+/// The engine controller.
+#[derive(Debug, Clone)]
+pub struct EngineController {
+    /// The block head state.
+    pub unsafe_head: L2BlockInfo,
+    /// A cross unsafe head.
+    pub cross_unsafe_head: L2BlockInfo,
+    /// The pending local safe head.
+    pub pending_local_safe_head: L2BlockInfo, 
+    /// The local safe head.
+    pub local_safe_head: L2BlockInfo,
+    /// Derived from L1 and cross-verified.
+    pub safe_head: L2BlockInfo,
+    /// The finalized safe head.
+    pub finalized_head: L2BlockInfo,
+}
diff --git a/crates/rollup/src/engine/mod.rs b/crates/rollup/src/engine/mod.rs
new file mode 100644
index 0000000..a2ae6a6
--- /dev/null
+++ b/crates/rollup/src/engine/mod.rs
@@ -0,0 +1,7 @@
+//! The engine module contains logic for interacting with the L2 Engine API.
+
+mod controller;
+pub use controller::EngineController;
+
+mod relay;
+pub use relay::EngineRelay;
diff --git a/crates/rollup/src/engine.rs b/crates/rollup/src/engine/relay.rs
similarity index 91%
rename from crates/rollup/src/engine.rs
rename to crates/rollup/src/engine/relay.rs
index 36601e1..806a16b 100644
--- a/crates/rollup/src/engine.rs
+++ b/crates/rollup/src/engine/relay.rs
@@ -1,3 +1,5 @@
+//! The engine relay handles forwarding [OpAttributesWithParent] to the L2 Engine API.
+
 use std::ops::Deref;
 
 use alloy_network::AnyNetwork;
@@ -25,12 +27,12 @@ type HyperAuthClient<B = Full<Bytes>> = HyperClient<B, AuthService<Client<HttpCo
 
 /// The [`Engine`] is responsible for interacting with an L2 Engine API server.
 #[derive(Debug, Clone)]
-pub struct Engine {
+pub struct EngineRelay {
     provider: RootProvider<Http<HyperAuthClient>, AnyNetwork>,
 }
 
-impl Engine {
-    /// Creates a new [`Engine`] from the provided [Url] and [JwtSecret].
+impl EngineRelay {
+    /// Creates a new [`EngineRelay`] from the provided [Url] and [JwtSecret].
     pub fn new_http(url: Url, jwt: JwtSecret) -> Self {
         let hyper_client = Client::builder(TokioExecutor::new()).build_http::<Full<Bytes>>();
 
@@ -66,7 +68,7 @@ impl Engine {
     }
 }
 
-impl Deref for Engine {
+impl Deref for EngineRelay {
     type Target = RootProvider<Http<HyperAuthClient>, AnyNetwork>;
 
     fn deref(&self) -> &Self::Target {
diff --git a/crates/rollup/src/lib.rs b/crates/rollup/src/lib.rs
index 400baaf..f0b31be 100644
--- a/crates/rollup/src/lib.rs
+++ b/crates/rollup/src/lib.rs
@@ -11,7 +11,7 @@ mod cli;
 pub use cli::HeraArgsExt;
 
 mod engine;
-pub use engine::Engine;
+pub use engine::{EngineRelay, EngineController};
 
 mod validator;
 pub use validator::TrustedPayloadValidator;