diff --git a/src/derive/command/readlen.rs b/src/derive/command/readlen.rs
index 5bce4cc..92bf47c 100644
--- a/src/derive/command/readlen.rs
+++ b/src/derive/command/readlen.rs
@@ -82,5 +82,5 @@ pub fn derive(args: DeriveReadlenArgs) -> anyhow::Result<()> {
     let output = serde_json::to_string_pretty(&result).unwrap();
     print!("{}", output);
 
-    Ok(())
+    anyhow::Ok(())
 }
diff --git a/src/derive/readlen/compute.rs b/src/derive/readlen/compute.rs
index 183a4de..0e10c56 100644
--- a/src/derive/readlen/compute.rs
+++ b/src/derive/readlen/compute.rs
@@ -69,7 +69,7 @@ pub fn predict(
         result.consensus_read_length = Some(consensus_read_length);
     }
 
-    Ok(result)
+    anyhow::Ok(result)
 }
 
 #[cfg(test)]