diff --git a/AGENTS.md b/AGENTS.md
index 0b4bf2f8..67375238 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -494,10 +494,11 @@ IO.puts("Statement expects #{param_count} parameter(s)")  # Prints: 1
 IO.puts("Result will have #{col_count} column(s)")  # Prints: 4
 
 # Get column names
-{:ok, col_names} = Enum.map(0..(col_count-1), fn i ->
-  {:ok, name} = EctoLibSql.Native.statement_column_name(state, stmt_id, i)
-  name
-end)
+col_names =
+  Enum.map(0..(col_count - 1), fn i ->
+    {:ok, name} = EctoLibSql.Native.statement_column_name(state, stmt_id, i)
+    name
+  end)
 IO.inspect(col_names)  # Prints: ["id", "name", "email", "created_at"]
 
 :ok = EctoLibSql.Native.close_stmt(stmt_id)
diff --git a/IMPLEMENTATION_ROADMAP_FOCUSED.md b/IMPLEMENTATION_ROADMAP_FOCUSED.md
index 39c1baaa..2b0b2fca 100644
--- a/IMPLEMENTATION_ROADMAP_FOCUSED.md
+++ b/IMPLEMENTATION_ROADMAP_FOCUSED.md
@@ -195,10 +195,9 @@ Logger.info("Current replication frame: #{current_frame}")
 ```
 
 **libsql API**:
-- `database.sync_until(frame_no)` - Sync until specific frame
-- `database.get_frame_no()` - Get current frame number
-- `database.flush_replicator()` - Flush pending replication
-- `database.sync_frames(count)` - Sync specific number of frames
+- `replication_index()` - Get current frame number
+- `sync()` / `sync_until(frame_no)` - Sync replica until specific frame
+- `flush_replicator()` - Flush pending replication
 
 **Implementation**:
 - [x] Add `sync_until(conn_id, frame_no)` NIF
diff --git a/native/ecto_libsql/src/lib.rs b/native/ecto_libsql/src/lib.rs
index 1a1b973d..8593eab8 100644
--- a/native/ecto_libsql/src/lib.rs
+++ b/native/ecto_libsql/src/lib.rs
@@ -145,6 +145,45 @@ fn decode_transaction_behavior(atom: Atom) -> Option<TransactionBehavior> {
     }
 }
 
+/// Helper function to verify transaction ownership.
+///
+/// Returns an error if the transaction does not belong to the specified connection.
+fn verify_transaction_ownership(
+    entry: &TransactionEntry,
+    conn_id: &str,
+) -> Result<(), rustler::Error> {
+    if entry.conn_id != conn_id {
+        return Err(rustler::Error::Term(Box::new(
+            "Transaction does not belong to this connection",
+        )));
+    }
+    Ok(())
+}
+
+/// Helper function to verify statement ownership.
+///
+/// Returns an error if the statement does not belong to the specified connection.
+fn verify_statement_ownership(stmt_conn_id: &str, conn_id: &str) -> Result<(), rustler::Error> {
+    if stmt_conn_id != conn_id {
+        return Err(rustler::Error::Term(Box::new(
+            "Statement does not belong to connection",
+        )));
+    }
+    Ok(())
+}
+
+/// Helper function to verify cursor ownership.
+///
+/// Returns an error if the cursor does not belong to the specified connection.
+fn verify_cursor_ownership(cursor: &CursorData, conn_id: &str) -> Result<(), rustler::Error> {
+    if cursor.conn_id != conn_id {
+        return Err(rustler::Error::Term(Box::new(
+            "Cursor does not belong to connection",
+        )));
+    }
+    Ok(())
+}
+
 #[rustler::nif(schedule = "DirtyIo")]
 pub fn begin_transaction(conn_id: &str) -> NifResult<String> {
     let conn_map = safe_lock(&CONNECTION_REGISTRY, "begin_transaction conn_map")?;
@@ -226,11 +265,7 @@ pub fn execute_with_transaction<'a>(
         .ok_or_else(|| rustler::Error::Term(Box::new("Transaction not found")))?;
 
     // Verify transaction belongs to this connection
-    if entry.conn_id != conn_id {
-        return Err(rustler::Error::Term(Box::new(
-            "Transaction does not belong to this connection",
-        )));
-    }
+    verify_transaction_ownership(entry, conn_id)?;
 
     let decoded_args: Vec<Value> = args
         .into_iter()
@@ -260,11 +295,7 @@ pub fn query_with_trx_args<'a>(
         .ok_or_else(|| rustler::Error::Term(Box::new("Transaction not found")))?;
 
     // Verify transaction belongs to this connection
-    if entry.conn_id != conn_id {
-        return Err(rustler::Error::Term(Box::new(
-            "Transaction does not belong to this connection",
-        )));
-    }
+    verify_transaction_ownership(entry, conn_id)?;
 
     let decoded_args: Vec<Value> = args
         .into_iter()
@@ -941,11 +972,7 @@ fn query_prepared<'a>(
         .ok_or_else(|| rustler::Error::Term(Box::new("Statement not found")))?;
 
     // Verify statement belongs to this connection
-    if stored_conn_id != conn_id {
-        return Err(rustler::Error::Term(Box::new(
-            "Statement does not belong to connection",
-        )));
-    }
+    verify_statement_ownership(stored_conn_id, conn_id)?;
 
     let cached_stmt = cached_stmt.clone();
 
@@ -1005,11 +1032,7 @@ fn execute_prepared<'a>(
         .ok_or_else(|| rustler::Error::Term(Box::new("Statement not found")))?;
 
     // Verify statement belongs to this connection
-    if stored_conn_id != conn_id {
-        return Err(rustler::Error::Term(Box::new(
-            "Statement does not belong to connection",
-        )));
-    }
+    verify_statement_ownership(stored_conn_id, conn_id)?;
 
     let cached_stmt = cached_stmt.clone();
 
@@ -1341,11 +1364,7 @@ fn fetch_cursor<'a>(
         .ok_or_else(|| rustler::Error::Term(Box::new("Cursor not found")))?;
 
     // Verify cursor belongs to this connection
-    if cursor.conn_id != conn_id {
-        return Err(rustler::Error::Term(Box::new(
-            "Cursor does not belong to connection",
-        )));
-    }
+    verify_cursor_ownership(cursor, conn_id)?;
 
     let remaining = cursor.rows.len().saturating_sub(cursor.position);
     let fetch_count = remaining.min(max_rows);
@@ -1623,11 +1642,7 @@ fn statement_column_count(conn_id: &str, stmt_id: &str) -> NifResult<usize> {
         .ok_or_else(|| rustler::Error::Term(Box::new("Statement not found")))?;
 
     // Verify statement belongs to this connection
-    if stored_conn_id != conn_id {
-        return Err(rustler::Error::Term(Box::new(
-            "Statement does not belong to connection",
-        )));
-    }
+    verify_statement_ownership(stored_conn_id, conn_id)?;
 
     let cached_stmt = cached_stmt.clone();
 
@@ -1656,11 +1671,7 @@ fn statement_column_name(conn_id: &str, stmt_id: &str, idx: usize) -> NifResult<
         .ok_or_else(|| rustler::Error::Term(Box::new("Statement not found")))?;
 
     // Verify statement belongs to this connection
-    if stored_conn_id != conn_id {
-        return Err(rustler::Error::Term(Box::new(
-            "Statement does not belong to connection",
-        )));
-    }
+    verify_statement_ownership(stored_conn_id, conn_id)?;
 
     let cached_stmt = cached_stmt.clone();
 
@@ -1699,11 +1710,7 @@ fn statement_parameter_count(conn_id: &str, stmt_id: &str) -> NifResult<usize> {
         .ok_or_else(|| rustler::Error::Term(Box::new("Statement not found")))?;
 
     // Verify statement belongs to this connection
-    if stored_conn_id != conn_id {
-        return Err(rustler::Error::Term(Box::new(
-            "Statement does not belong to connection",
-        )));
-    }
+    verify_statement_ownership(stored_conn_id, conn_id)?;
 
     let cached_stmt = cached_stmt.clone();