From 03bae6424ef74c2285198e0b1d0133c285350994 Mon Sep 17 00:00:00 2001
From: slhafzjw <slhafzjw@slhaf.work>
Date: Sat, 25 Apr 2026 00:11:57 +0800
Subject: [PATCH] fix(openai-provider): ensure structured chat adds JSON
 instruction when missing

---
 .../openai/OpenAiCompatibleProvider.java      | 36 ++++++++++++++++---
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/Partner-Framework/src/main/java/work/slhaf/partner/framework/agent/model/provider/openai/OpenAiCompatibleProvider.java b/Partner-Framework/src/main/java/work/slhaf/partner/framework/agent/model/provider/openai/OpenAiCompatibleProvider.java
index 8154789b..5ae7f4eb 100644
--- a/Partner-Framework/src/main/java/work/slhaf/partner/framework/agent/model/provider/openai/OpenAiCompatibleProvider.java
+++ b/Partner-Framework/src/main/java/work/slhaf/partner/framework/agent/model/provider/openai/OpenAiCompatibleProvider.java
@@ -17,10 +17,7 @@ import work.slhaf.partner.framework.agent.model.provider.ProviderOverride;
 import work.slhaf.partner.framework.agent.support.Result;
 
 import java.time.Duration;
-import java.util.Iterator;
-import java.util.LinkedHashMap;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 
 public class OpenAiCompatibleProvider extends ModelProvider {
 
@@ -103,7 +100,7 @@ public class OpenAiCompatibleProvider extends ModelProvider {
         return executeWithRetry(
                 "OpenAI-compatible provider failed to complete the structured chat request after 3 attempts.",
                 () -> {
-                    StructuredChatCompletionCreateParams<T> params = buildParams(messages).toBuilder()
+                    StructuredChatCompletionCreateParams<T> params = buildParams(ensureJsonInstruction(messages)).toBuilder()
                             .responseFormat(responseType)
                             .build();
                     return extractStructured(client.chat().completions().create(params));
@@ -111,6 +108,35 @@ public class OpenAiCompatibleProvider extends ModelProvider {
         );
     }
 
+    private List<Message> ensureJsonInstruction(List<Message> messages) {
+        boolean containsJsonInstruction = messages.stream()
+                .map(Message::getContent)
+                .filter(content -> !content.isBlank())
+                .anyMatch(content -> content.toLowerCase(Locale.ROOT).contains("json"));
+        if (containsJsonInstruction) {
+            return messages;
+        }
+
+        String jsonInstruction = "Return only a valid JSON object that matches the requested response schema.";
+        List<Message> patched = new ArrayList<>(messages.size() + 1);
+        boolean merged = false;
+        for (Message message : messages) {
+            if (!merged && message.getRole() == Message.Character.SYSTEM) {
+                patched.add(new Message(
+                        Message.Character.SYSTEM,
+                        message.getContent() + "\n\n" + jsonInstruction
+                ));
+                merged = true;
+                continue;
+            }
+            patched.add(message);
+        }
+        if (!merged) {
+            patched.addFirst(new Message(Message.Character.SYSTEM, jsonInstruction));
+        }
+        return patched;
+    }
+
     private ChatCompletionCreateParams buildParams(List<Message> messages) {
         ChatCompletionCreateParams.Builder paramsBuilder = ChatCompletionCreateParams.builder()
                 .model(model)