fix(agent): keep cot action names and parse multiple code fences

api/core/agent/output_parser/cot_output_parser.py

@@ -26,9 +26,10 @@ def parse_action(action) -> str | AgentScratchpadUnit.Action:
                 action = action[0]
 
             for key, value in action.items():
-                if "input" in key.lower():
+                key_lower = key.lower()
+                if "input" in key_lower:
                     action_input = value
-                else:
+                elif key_lower == "action":
                     action_name = value
 
             if action_name is not None and action_input is not None:
@@ -40,13 +41,17 @@ def parse_action(action) -> str | AgentScratchpadUnit.Action:
                 return json.dumps(action)
 
         def extra_json_from_code_block(code_block) -> list[list | dict]:
-            blocks = re.findall(r"```[json]*\s*([\[{].*[]}])\s*```", code_block, re.DOTALL | re.IGNORECASE)
+            # One match per fenced block: a non-greedy body keeps two separate
+            # fences from being read as one object spanning both (#45324).
+            blocks = re.findall(r"```(?:json)?\s*(.*?)\s*```", code_block, re.DOTALL | re.IGNORECASE)
             if not blocks:
                 return []
             try:
                 json_blocks = []
                 for block in blocks:
                     json_text = re.sub(r"^[a-zA-Z]+\n", "", block.strip(), flags=re.MULTILINE)
+                    if not json_text.lstrip().startswith(("{", "[")):
+                        continue
                     json_blocks.append(json.loads(json_text, strict=False))
                 return json_blocks
             except Exception:

api/tests/unit_tests/core/agent/output_parser/test_cot_output_parser.py

@@ -99,6 +99,38 @@ def test_json_list_unwrap(self, make_chunk, usage_dict) -> None:
             AgentScratchpadUnit.Action(action_name="lookup", action_input="abc")
         ]
 
+    def test_action_name_ignores_supplementary_keys(self, make_chunk, usage_dict) -> None:
+        content = (
+            '{"action": "google_search", "action_input": {"query": "latest AI news"}, '
+            '"thought": "I should search Google for the latest AI news"}'
+        )
+        chunks = [make_chunk(content)]
+        result = list(CotAgentOutputParser.handle_react_stream_output(chunks, usage_dict))
+        assert result == [
+            AgentScratchpadUnit.Action(
+                action_name="google_search",
+                action_input={"query": "latest AI news"},
+            )
+        ]
+
+    def test_code_block_multiple_fences_are_parsed_independently(self, make_chunk, usage_dict) -> None:
+        content = """```json
+{"action": "a1", "input": "x"}
+```
+
+Some prose between blocks.
+
+```json
+{"action": "a2", "input": "y"}
+```"""
+        chunks = [make_chunk(content)]
+        result = list(CotAgentOutputParser.handle_react_stream_output(chunks, usage_dict))
+        actions = [item for item in result if isinstance(item, AgentScratchpadUnit.Action)]
+        assert actions == [
+            AgentScratchpadUnit.Action(action_name="a1", action_input="x"),
+            AgentScratchpadUnit.Action(action_name="a2", action_input="y"),
+        ]
+
     def test_json_missing_fields_returns_string(self, make_chunk, usage_dict) -> None:
         content = '{"foo": "bar"}'
         chunks = [make_chunk(content)]