diff --git a/src/client.rs b/src/client.rs
index 05916a7..c5d9d3e 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -55,6 +55,7 @@ impl Client {
                     // TODO: perform actual auth.
                     // TODO: record startup parameters client sends over.
                     auth_ok(&mut stream).await?;
+                    server_parameters(&mut stream).await?;
                     ready_for_query(&mut stream).await?;
 
                     let (read, write) = stream.into_split();
@@ -135,6 +136,10 @@ impl Client {
 
                     'X' => {
                         // Client closing
+                        if server.in_transaction() {
+                            server.query("ROLLBACK").await?;
+                        }
+
                         return Ok(());
                     }
 
diff --git a/src/errors.rs b/src/errors.rs
index 47510f4..cb7e756 100644
--- a/src/errors.rs
+++ b/src/errors.rs
@@ -6,4 +6,5 @@ pub enum Error {
     ProtocolSyncError,
     ServerError,
     ServerTimeout,
+    DirtyServer,
 }
diff --git a/src/messages.rs b/src/messages.rs
index 86ad681..2ba4b37 100644
--- a/src/messages.rs
+++ b/src/messages.rs
@@ -16,6 +16,18 @@ pub async fn auth_ok(stream: &mut TcpStream) -> Result<(), Error> {
     Ok(write_all(stream, auth_ok).await?)
 }
 
+pub async fn server_parameters(stream: &mut TcpStream) -> Result<(), Error> {
+    let client_encoding = BytesMut::from(&b"client_encoding\0UTF8\0"[..]);
+    let len = client_encoding.len() as i32 + 4; // TODO: add more parameters here
+    let mut res = BytesMut::with_capacity(len as usize + 1);
+
+    res.put_u8(b'S');
+    res.put_i32(len);
+    res.put_slice(&client_encoding[..]);
+
+    Ok(write_all(stream, res).await?)
+}
+
 pub async fn ready_for_query(stream: &mut TcpStream) -> Result<(), Error> {
     let mut bytes = BytesMut::with_capacity(5);
 
diff --git a/src/pool.rs b/src/pool.rs
index b2074a4..2683e17 100644
--- a/src/pool.rs
+++ b/src/pool.rs
@@ -50,6 +50,11 @@ impl ManageConnection for ServerPool {
     async fn is_valid(&self, conn: &mut PooledConnection<'_, Self>) -> Result<(), Self::Error> {
         let server = &mut *conn;
 
+        // Client disconnected before cleaning up
+        if server.in_transaction() {
+            return Err(Error::DirtyServer);
+        }
+
         // If this fails, the connection will be closed and another will be grabbed from the pool quietly :-).
         // Failover, step 1, complete.
         match tokio::time::timeout(
diff --git a/tests/python/.gitignore b/tests/python/.gitignore
new file mode 100644
index 0000000..eba74f4
--- /dev/null
+++ b/tests/python/.gitignore
@@ -0,0 +1 @@
+venv/
\ No newline at end of file
diff --git a/tests/python/requirements.txt b/tests/python/requirements.txt
new file mode 100644
index 0000000..d7661d4
--- /dev/null
+++ b/tests/python/requirements.txt
@@ -0,0 +1 @@
+psycopg2==2.9.3
diff --git a/tests/python/tests.py b/tests/python/tests.py
new file mode 100644
index 0000000..c3fa47a
--- /dev/null
+++ b/tests/python/tests.py
@@ -0,0 +1,9 @@
+import psycopg2
+
+conn = psycopg2.connect("postgres://random:password@127.0.0.1:5433/db")
+cur = conn.cursor()
+
+cur.execute("SELECT 123");
+res = cur.fetchall()
+
+print(res)
\ No newline at end of file