fix: accept fenced JSON output in raw JSON mode for OpenAI-compatible backends

docs/examples/japanese_extraction.md

@@ -51,7 +51,7 @@ for entity in result.extractions:
     if entity.char_interval:
         start, end = entity.char_interval.start_pos, entity.char_interval.end_pos
         position_info = f" (pos: {start}-{end})"
-    
+
     print(f"• {entity.extraction_class}: {entity.extraction_text}{position_info}")
 
 # Expected Output:

langextract/core/format_handler.py

@@ -288,8 +288,31 @@ def _extract_content(self, text: str) -> str:
       FormatParseError: When fences required but not found or multiple
         blocks found.
     """
+    strip_text = text.strip()
     if not self.use_fences:
-      return text.strip()
+      matches = list(_FENCE_RE.finditer(text))
+
+      if matches:
+        valid_tags = {
+            data.FormatType.YAML: {_YAML_FORMAT, _YML_FORMAT},
+            data.FormatType.JSON: {_JSON_FORMAT},
+        }
+        candidates = [
+            m
+            for m in matches
+            if self._is_valid_language_tag(m.group("lang"), valid_tags)
+        ]
+
+        if len(candidates) == 1:
+          return candidates[0].group("body").strip()
+        if len(candidates) > 1:
+          raise exceptions.FormatParseError(
+              "Multiple fenced blocks found. Expected exactly one."
+          )
+        if not self.strict_fences and len(matches) == 1:
+          return matches[0].group("body").strip()
+
+      return strip_text
 
     matches = list(_FENCE_RE.finditer(text))
 
@@ -330,7 +353,7 @@ def _extract_content(self, text: str) -> str:
           f"No {self.format_type.value} code block found."
       )
 
-    return text.strip()
+    return strip_text
 
   # ---- Backward compatibility methods (to be removed in v2.0.0) ----
 

tests/format_handler_test.py

@@ -273,6 +273,24 @@ def test_think_tags_stripped_before_parsing(self):
     self.assertLen(parsed, 1)
     self.assertEqual(parsed[0]["person"], "Alice")
 
+  def test_fenced_json_accepted_when_fences_disabled(self):
+    # Some OpenAI-compatible backends may return fenced JSON even when raw
+    # JSON mode is expected.
+    handler = format_handler.FormatHandler(
+        format_type=data.FormatType.JSON,
+        use_wrapper=True,
+        wrapper_key="extractions",
+        use_fences=False,
+    )
+    fenced_json = textwrap.dedent("""
+        ```json
+        {"extractions": [{"person": "Alice"}]}
+        ```
+    """).strip()
+    parsed = handler.parse_output(fenced_json)
+    self.assertLen(parsed, 1)
+    self.assertEqual(parsed[0]["person"], "Alice")
+
   def test_top_level_list_accepted_as_fallback(self):
     # Some models return [...] instead of {"extractions": [...]}
     handler = format_handler.FormatHandler(