diff --git a/crates/arroyo-worker/src/lib.rs b/crates/arroyo-worker/src/lib.rs
index a6f2f914a..a767652fa 100644
--- a/crates/arroyo-worker/src/lib.rs
+++ b/crates/arroyo-worker/src/lib.rs
@@ -412,7 +412,9 @@ impl WorkerGrpc for WorkerServer {
         let logical = LogicalProgram::try_from(req.program.expect("Program is None"))
             .expect("Failed to create LogicalProgram");
 
-        debug!("Starting execution for graph\n{}", to_d2(&logical));
+        if let Ok(v) = to_d2(&logical) {
+            debug!("Starting execution for graph\n{}", v);
+        }
 
         for (udf_name, dylib_config) in &logical.program_config.udf_dylibs {
             info!("Loading UDF {}", udf_name);
diff --git a/crates/arroyo-worker/src/utils.rs b/crates/arroyo-worker/src/utils.rs
index cf153cd7f..b615e12d4 100644
--- a/crates/arroyo-worker/src/utils.rs
+++ b/crates/arroyo-worker/src/utils.rs
@@ -1,4 +1,5 @@
 use crate::engine::construct_operator;
+use anyhow::bail;
 use arrow_schema::Schema;
 use arroyo_datastream::logical::LogicalProgram;
 use arroyo_df::physical::new_registry;
@@ -13,20 +14,17 @@ fn format_arrow_schema_fields(schema: &Schema) -> Vec<(String, String)> {
         .collect()
 }
 
-pub fn to_d2(logical: &LogicalProgram) -> String {
+pub fn to_d2(logical: &LogicalProgram) -> anyhow::Result<String> {
     let registry = Arc::new(new_registry());
-    assert!(
-        logical.program_config.udf_dylibs.is_empty(),
-        "UDFs not supported"
-    );
-    assert!(
-        logical.program_config.python_udfs.is_empty(),
-        "UDFs not supported"
-    );
+
+    if !logical.program_config.udf_dylibs.is_empty()
+        || !logical.program_config.python_udfs.is_empty()
+    {
+        bail!("UDFs are not yet supported in the pipeline visualizer");
+    }
 
     let mut d2 = String::new();
 
-    // Nodes
     for idx in logical.graph.node_indices() {
         let node = logical.graph.node_weight(idx).unwrap();
         let operator = construct_operator(
@@ -36,7 +34,6 @@ pub fn to_d2(logical: &LogicalProgram) -> String {
         );
         let display = operator.display();
 
-        // Create a Markdown-formatted label with operator details
         let mut label = format!("### {} ({})", operator.name(), &display.name);
         for (field, value) in display.fields {
             label.push_str(&format!("\n- **{}**: {}", field, value));
@@ -56,37 +53,30 @@ pub fn to_d2(logical: &LogicalProgram) -> String {
         .unwrap();
     }
 
-    // Edges and Schema Nodes
     for idx in logical.graph.edge_indices() {
         let edge = logical.graph.edge_weight(idx).unwrap();
         let (from, to) = logical.graph.edge_endpoints(idx).unwrap();
 
-        // Edge label (could be empty or minimal)
         let edge_label = format!("{}", edge.edge_type);
 
-        // Create a schema node using sql_table shape
         let schema_node_name = format!("schema_{}", idx.index());
         let schema_fields = format_arrow_schema_fields(&edge.schema.schema);
 
-        // Begin schema node definition
         writeln!(&mut d2, "{}: {{", schema_node_name).unwrap();
         writeln!(&mut d2, "  shape: sql_table").unwrap();
 
-        // Add fields to the schema node
         for (field_name, field_type) in schema_fields {
             writeln!(
                 &mut d2,
-                "  \"{}\": \"{}\"", // Field definition
+                "  \"{}\": \"{}\"",
                 field_name.replace("\"", "\\\""),
                 field_type.replace("\"", "\\\"")
             )
             .unwrap();
         }
 
-        // End schema node definition
         writeln!(&mut d2, "}}").unwrap();
 
-        // Connect source operator to schema node
         writeln!(
             &mut d2,
             "{} -> {}: \"{}\"",
@@ -96,9 +86,8 @@ pub fn to_d2(logical: &LogicalProgram) -> String {
         )
         .unwrap();
 
-        // Connect schema node to destination operator
         writeln!(&mut d2, "{} -> {}", schema_node_name, to.index()).unwrap();
     }
 
-    d2
+    Ok(d2)
 }
diff --git a/crates/arroyo/src/main.rs b/crates/arroyo/src/main.rs
index 01c025f5c..bbab8b013 100644
--- a/crates/arroyo/src/main.rs
+++ b/crates/arroyo/src/main.rs
@@ -484,7 +484,7 @@ async fn visualize(query: Input, open: bool) {
 
     if open {
         let tmp = temp_dir().join("plan.d2");
-        tokio::fs::write(&tmp, utils::to_d2(&compiled.program))
+        tokio::fs::write(&tmp, utils::to_d2(&compiled.program).unwrap())
             .await
             .expect("Failed to write plan");
         let output = tmp.with_extension("svg");
@@ -506,6 +506,6 @@ async fn visualize(query: Input, open: bool) {
 
         let _ = open::that(format!("file://{}", output.to_string_lossy()));
     } else {
-        println!("{}", utils::to_d2(&compiled.program));
+        println!("{}", utils::to_d2(&compiled.program).unwrap());
     }
 }