fix: gemini with functions that have empty parameters (#666)

1 files changed, 12 insertions, 1 deletions

diff --git a/src/client/vertexai.rs b/src/client/vertexai.rs
index cc7e464..a4c4050 100644
--- a/src/client/vertexai.rs
+++ b/src/client/vertexai.rs
@@ -353,7 +353,18 @@ pub fn gemini_build_chat_completions_body(
     }
 
     if let Some(functions) = functions {
-        body["tools"] = json!([{ "functionDeclarations": *functions }]);
+        // Gemini doesn't support functions with parameters that have empty properties, so we need to patch it.
+        let function_declarations: Vec<_> = functions.into_iter().map(|function| {
+            if function.parameters.is_empty_properties() {
+                json!({
+                    "name": function.name,
+                    "description": function.description,
+                })
+            } else {
+                json!(function)
+            }
+        }).collect();
+        body["tools"] = json!([{ "functionDeclarations": function_declarations }]);
     }
 
     Ok(body)