diff --git a/nexus/src/app/background/tasks/support_bundle_collector.rs b/nexus/src/app/background/tasks/support_bundle_collector.rs
index 2190a836a34..5eec11e35e6 100644
--- a/nexus/src/app/background/tasks/support_bundle_collector.rs
+++ b/nexus/src/app/background/tasks/support_bundle_collector.rs
@@ -5,6 +5,7 @@
 //! Background task for managing Support Bundles
 
 use crate::app::background::BackgroundTask;
+use anyhow::Context;
 use camino::Utf8DirEntry;
 use camino::Utf8Path;
 use camino_tempfile::Utf8TempDir;
@@ -772,7 +773,7 @@ async fn sha2_hash(file: &mut tokio::fs::File) -> anyhow::Result<ArtifactHash> {
 }
 
 /// Run a `sled-dianostics` future and save its output to a corresponding file.
-async fn save_diag_cmd_output_or_error<F, D: std::fmt::Debug>(
+async fn save_diag_cmd_output_or_error<F, S: serde::Serialize>(
     path: &Utf8Path,
     command: &str,
     future: F,
@@ -780,7 +781,7 @@ async fn save_diag_cmd_output_or_error<F, D: std::fmt::Debug>(
 where
     F: Future<
             Output = Result<
-                sled_agent_client::ResponseValue<D>,
+                sled_agent_client::ResponseValue<S>,
                 sled_agent_client::Error<sled_agent_client::types::Error>,
             >,
         > + Send,
@@ -789,11 +790,14 @@ where
     match result {
         Ok(result) => {
             let output = result.into_inner();
-            tokio::fs::write(
-                path.join(format!("{command}.txt")),
-                format!("{output:?}"),
-            )
-            .await?;
+            let json = serde_json::to_string(&output).with_context(|| {
+                format!("failed to serialize {command} output as json")
+            })?;
+            tokio::fs::write(path.join(format!("{command}.json")), json)
+                .await
+                .with_context(|| {
+                    format!("failed to write output of {command} to file")
+                })?;
         }
         Err(err) => {
             tokio::fs::write(