diff --git a/log10/prompt_analyzer.py b/log10/prompt_analyzer.py
index 2a1dc1f0..20d5f563 100644
--- a/log10/prompt_analyzer.py
+++ b/log10/prompt_analyzer.py
@@ -83,7 +83,7 @@ def _suggest(self, prompt_json: json, report: dict | None = None) -> dict:
             report = json.dumps(report)
 
         json_payload = {
-            "base_prompt": prompt_json,
+            "base_prompt": json.dumps(prompt_json),
             "report": report,
             "session_id": self.__session_id,
         }