diff --git a/apis/python/operator/src/lib.rs b/apis/python/operator/src/lib.rs
index bb7054dc..91451fe9 100644
--- a/apis/python/operator/src/lib.rs
+++ b/apis/python/operator/src/lib.rs
@@ -1,8 +1,9 @@
-use std::{borrow::Cow, sync::Arc};
+use std::sync::Arc;
 
-use arrow::pyarrow::PyArrowConvert;
+use arrow::pyarrow::{FromPyArrow, ToPyArrow};
+use arrow_schema::DataType;
 use dora_node_api::{Data, Event, Metadata, MetadataParameters};
-use eyre::{Context, Result};
+use eyre::{bail, Context, ContextCompat, Result};
 use pyo3::{
     exceptions::PyLookupError,
     prelude::*,
@@ -62,9 +63,22 @@ impl PyEvent {
     /// Returns the payload of an input event as an arrow array (if any).
     fn value(&self, py: Python<'_>) -> PyResult<Option<PyObject>> {
         if let Some(data) = &self.data {
+            let data_type = match &self.event {
+                Event::Input { metadata, .. } => match &metadata
+                    .schema
+                    .fields()
+                    .first()
+                    .context("no field in schema")?
+                    .data_type()
+                {
+                    DataType::List(field) => field.data_type().clone(),
+                    _ => todo!(),
+                },
+                _ => DataType::UInt8,
+            };
             let array = data
                 .clone()
-                .into_arrow_array()
+                .into_arrow_array(data_type)
                 .map_err(|err| arrow::pyarrow::PyArrowException::new_err(err.to_string()))?;
             // TODO: Does this call leak data?
             let array_data = array.to_pyarrow(py)?;
@@ -117,7 +131,7 @@ pub fn pydict_to_metadata(dict: Option<&PyDict>) -> Result<MetadataParameters> {
                     let otel_context: &str = value
                         .extract()
                         .context("parsing open telemetry context failed")?;
-                    default_metadata.open_telemetry_context = Cow::Borrowed(otel_context);
+                    default_metadata.open_telemetry_context = otel_context.to_string();
                 }
                 _ => (),
             }
@@ -141,14 +155,11 @@ pub fn python_output_len(data: &PyObject, py: Python) -> eyre::Result<usize> {
     if let Ok(py_bytes) = data.downcast::<PyBytes>(py) {
         py_bytes.len().wrap_err("failed to get length of PyBytes")
     } else if let Ok(arrow_array) = arrow::array::ArrayData::from_pyarrow(data.as_ref(py)) {
-        if arrow_array.data_type() != &arrow::datatypes::DataType::UInt8 {
-            eyre::bail!("only arrow arrays with data type `UInt8` are supported");
-        }
         if arrow_array.buffers().len() != 1 {
             eyre::bail!("output arrow array must contain a single buffer");
         }
 
-        Ok(arrow_array.len())
+        Ok(arrow_array.buffers()[0].len())
     } else {
         eyre::bail!("invalid `data` type, must by `PyBytes` or arrow array")
     }
@@ -163,15 +174,15 @@ pub fn process_python_output<T>(
         let data = py_bytes.as_bytes();
         callback(data)
     } else if let Ok(arrow_array) = arrow::array::ArrayData::from_pyarrow(data.as_ref(py)) {
-        if arrow_array.data_type() != &arrow::datatypes::DataType::UInt8 {
-            eyre::bail!("only arrow arrays with data type `UInt8` are supported");
-        }
         if arrow_array.buffers().len() != 1 {
             eyre::bail!("output arrow array must contain a single buffer");
         }
 
-        let len = arrow_array.len();
-        let slice = &arrow_array.buffer(0)[..len];
+        let buffers = arrow_array.buffers();
+        if buffers.len() != 1 {
+            bail!("Arrow array must contain a single buffer");
+        }
+        let slice = buffers[0];
 
         callback(slice)
     } else {
diff --git a/binaries/runtime/src/operator/python.rs b/binaries/runtime/src/operator/python.rs
index 7e211236..acfaf6c8 100644
--- a/binaries/runtime/src/operator/python.rs
+++ b/binaries/runtime/src/operator/python.rs
@@ -310,17 +310,18 @@ mod callback_impl {
                 Ok(())
             })?;
 
-            let metadata = pydict_to_metadata(metadata)
+            let parameters = pydict_to_metadata(metadata)
                 .wrap_err("failed to parse metadata")?
                 .into_owned();
+            let data_type = process_python_type(&data, py)?;
 
+            py.allow_threads(|| {
             let event = OperatorEvent::Output {
                 output_id: output.to_owned().into(),
-                metadata,
+                    data_type,
+                    parameters,
                 data: Some(sample),
             };
-
-            py.allow_threads(|| {
                 self.events_tx
                     .blocking_send(event)
                     .map_err(|_| eyre!("failed to send output to runtime"))