diff --git a/api/core/agent/base_agent_runner.py b/api/core/agent/base_agent_runner.py
index 806f7c6590f..c8bf7173161 100644
--- a/api/core/agent/base_agent_runner.py
+++ b/api/core/agent/base_agent_runner.py
@@ -1,8 +1,9 @@
 import json
 import logging
 import uuid
+from collections import Counter
 from decimal import Decimal
-from typing import Union, cast
+from typing import Any, Union, cast
 
 from sqlalchemy import func, select
 from sqlalchemy.orm import Session
@@ -48,6 +49,34 @@ logger = logging.getLogger(__name__)
 _file_access_controller = DatabaseFileAccessController()
 
 
+def _select_tool_occurrence(value: Any, occurrence: int, occurrences: int) -> Any:
+    """
+    Pick one call's value out of a persisted agent thought payload.
+
+    A tool called several times in one turn stores one value per call, in call
+    order. Records written before those calls were kept apart store a single
+    value for the tool name, and every occurrence replays it — the behaviour
+    those records were written with.
+
+    `observation` values are always `str`: `ToolEngine.agent_invoke` is typed
+    `-> tuple[str, list[str], ToolInvokeMeta]` and the runners store element 0,
+    so a list there is not a shape any writer produces and the length check is
+    defensive. `tool_input` values are `json.loads` of the model's `arguments`
+    with no shape check, so a legacy list-valued input is possible in principle;
+    on a length collision the rule reads per call, not whole —
+    `test_a_legacy_list_of_matching_length_is_read_per_call_not_whole` pins it.
+
+    The same function is defined, identically, in `models/model.py`.
+    The duplication is deliberate: `models/` importing from `core/agent/` is the
+    worse layering trade and the reverse is odd, so neither copy is in the wrong
+    place and neither should move. A change to this rule must be applied in both.
+    """
+    if occurrences > 1 and isinstance(value, list) and len(value) == occurrences:
+        return value[occurrence]
+
+    return value
+
+
 class BaseAgentRunner(AppRunner):
     def __init__(
         self,
@@ -408,7 +437,11 @@ class BaseAgentRunner(AppRunner):
                         else:
                             tool_responses = dict.fromkeys(tool_names, observation_payload)
 
+                        tool_occurrences = Counter(tool_names)
+                        seen_tools: Counter[str] = Counter()
                         for tool in tool_names:
+                            occurrence = seen_tools[tool]
+                            seen_tools[tool] += 1
                             # generate a uuid for tool call
                             tool_call_id = str(uuid.uuid4())
                             tool_calls.append(
@@ -417,13 +450,21 @@ class BaseAgentRunner(AppRunner):
                                     type="function",
                                     function=AssistantPromptMessage.ToolCall.ToolCallFunction(
                                         name=tool,
-                                        arguments=json.dumps(tool_inputs.get(tool, {})),
+                                        arguments=json.dumps(
+                                            _select_tool_occurrence(
+                                                tool_inputs.get(tool, {}), occurrence, tool_occurrences[tool]
+                                            )
+                                        ),
                                     ),
                                 )
                             )
                             tool_call_response.append(
                                 ToolPromptMessage(
-                                    content=tool_responses.get(tool, agent_thought.observation),
+                                    content=_select_tool_occurrence(
+                                        tool_responses.get(tool, agent_thought.observation),
+                                        occurrence,
+                                        tool_occurrences[tool],
+                                    ),
                                     name=tool,
                                     tool_call_id=tool_call_id,
                                 )
diff --git a/api/core/agent/fc_agent_runner.py b/api/core/agent/fc_agent_runner.py
index 78980f0d943..9c83d660eb0 100644
--- a/api/core/agent/fc_agent_runner.py
+++ b/api/core/agent/fc_agent_runner.py
@@ -43,6 +43,21 @@ _FILE_PREVIEW_ID_PATTERN = re.compile(r"/files/([a-fA-F0-9-]{36})/file-preview")
 _KNOWLEDGE_RETRIEVAL_PROMPT_NAME = "knowledge_retrieval"
 
 
+def _group_by_tool_name(items: list[tuple[str, Any]]) -> dict[str, Any]:
+    """
+    Group per-call values by tool name for the agent thought record.
+
+    A tool called once in a turn keeps its bare value, which is the shape every
+    record written so far uses. A tool called more than once keeps every value
+    in call order, so a repeated tool no longer discards all but the last one.
+    """
+    grouped: dict[str, list[Any]] = {}
+    for tool_name, value in items:
+        grouped.setdefault(tool_name, []).append(value)
+
+    return {tool_name: values[0] if len(values) == 1 else values for tool_name, values in grouped.items()}
+
+
 class FunctionCallAgentRunner(BaseAgentRunner):
     def _build_dataset_tool_image_contents(
         self, session: Session, tool_response: str, tool_instance: Any
@@ -201,13 +216,12 @@ class FunctionCallAgentRunner(BaseAgentRunner):
                         function_call_state = True
                         tool_calls.extend(self.extract_tool_calls(chunk) or [])
                         tool_call_names = ";".join([tool_call[1] for tool_call in tool_calls])
+                        grouped_inputs = _group_by_tool_name([(tool_call[1], tool_call[2]) for tool_call in tool_calls])
                         try:
-                            tool_call_inputs = json.dumps(
-                                {tool_call[1]: tool_call[2] for tool_call in tool_calls}, ensure_ascii=False
-                            )
+                            tool_call_inputs = json.dumps(grouped_inputs, ensure_ascii=False)
                         except TypeError:
                             # fallback: force ASCII to handle non-serializable objects
-                            tool_call_inputs = json.dumps({tool_call[1]: tool_call[2] for tool_call in tool_calls})
+                            tool_call_inputs = json.dumps(grouped_inputs)
 
                     if chunk.delta.message and chunk.delta.message.content:
                         if isinstance(chunk.delta.message.content, list):
@@ -228,13 +242,12 @@ class FunctionCallAgentRunner(BaseAgentRunner):
                     function_call_state = True
                     tool_calls.extend(self.extract_blocking_tool_calls(result) or [])
                     tool_call_names = ";".join([tool_call[1] for tool_call in tool_calls])
+                    grouped_inputs = _group_by_tool_name([(tool_call[1], tool_call[2]) for tool_call in tool_calls])
                     try:
-                        tool_call_inputs = json.dumps(
-                            {tool_call[1]: tool_call[2] for tool_call in tool_calls}, ensure_ascii=False
-                        )
+                        tool_call_inputs = json.dumps(grouped_inputs, ensure_ascii=False)
                     except TypeError:
                         # fallback: force ASCII to handle non-serializable objects
-                        tool_call_inputs = json.dumps({tool_call[1]: tool_call[2] for tool_call in tool_calls})
+                        tool_call_inputs = json.dumps(grouped_inputs)
 
                 if result.usage:
                     increase_usage(llm_usage, result.usage)
@@ -380,13 +393,18 @@ class FunctionCallAgentRunner(BaseAgentRunner):
                     tool_name="",
                     tool_input="",
                     thought="",
-                    tool_invoke_meta={
-                        tool_response["tool_call_name"]: tool_response["meta"] for tool_response in tool_responses
-                    },
-                    observation={
-                        tool_response["tool_call_name"]: tool_response["tool_response"]
-                        for tool_response in tool_responses
-                    },
+                    tool_invoke_meta=_group_by_tool_name(
+                        [
+                            (str(tool_response["tool_call_name"]), tool_response["meta"])
+                            for tool_response in tool_responses
+                        ]
+                    ),
+                    observation=_group_by_tool_name(
+                        [
+                            (str(tool_response["tool_call_name"]), tool_response["tool_response"])
+                            for tool_response in tool_responses
+                        ]
+                    ),
                     answer="",
                     messages_ids=message_file_ids,
                 )
diff --git a/api/core/ops/ops_trace_manager.py b/api/core/ops/ops_trace_manager.py
index 0066d035e54..e49bd518ec0 100644
--- a/api/core/ops/ops_trace_manager.py
+++ b/api/core/ops/ops_trace_manager.py
@@ -1197,6 +1197,12 @@ class TraceTask:
             if tool_name in agent_thought.tools:
                 created_time = agent_thought.created_at
                 tool_meta_data = agent_thought.tool_meta.get(tool_name, {})
+                if isinstance(tool_meta_data, list):
+                    # a tool called several times in one turn keeps one meta per
+                    # call; this trace covers the tool, not one call of it, so it
+                    # takes the last — the only one a record written before those
+                    # calls were kept apart had
+                    tool_meta_data = tool_meta_data[-1] if tool_meta_data else {}
                 tool_config = tool_meta_data.get("tool_config", {})
                 time_cost = tool_meta_data.get("time_cost", 0)
                 end_time = created_time + timedelta(seconds=time_cost)
diff --git a/api/models/model.py b/api/models/model.py
index 0cad0bb3feb..bdbef220400 100644
--- a/api/models/model.py
+++ b/api/models/model.py
@@ -3,6 +3,7 @@ from __future__ import annotations
 import json
 import re
 import uuid
+from collections import Counter
 from collections.abc import Callable, Mapping, Sequence
 from datetime import datetime
 from decimal import Decimal
@@ -2523,6 +2524,34 @@ class MessageChain(TypeBase):
     )
 
 
+def _select_tool_occurrence(value: Any, occurrence: int, occurrences: int) -> Any:
+    """
+    Pick one call's value out of a persisted agent thought payload.
+
+    A tool called several times in one turn stores one value per call, in call
+    order. Records written before those calls were kept apart store a single
+    value for the tool name, and every occurrence replays it — the behaviour
+    those records were written with.
+
+    `observation` values are always `str`: `ToolEngine.agent_invoke` is typed
+    `-> tuple[str, list[str], ToolInvokeMeta]` and the runners store element 0,
+    so a list there is not a shape any writer produces and the length check is
+    defensive. `tool_input` values are `json.loads` of the model's `arguments`
+    with no shape check, so a legacy list-valued input is possible in principle;
+    on a length collision the rule reads per call, not whole —
+    `test_a_legacy_list_of_matching_length_is_read_per_call_not_whole` pins it.
+
+    The same function is defined, identically, in `core/agent/base_agent_runner.py`.
+    The duplication is deliberate: `models/` importing from `core/agent/` is the
+    worse layering trade and the reverse is odd, so neither copy is in the wrong
+    place and neither should move. A change to this rule must be applied in both.
+    """
+    if occurrences > 1 and isinstance(value, list) and len(value) == occurrences:
+        return value[occurrence]
+
+    return value
+
+
 class MessageAgentThought(TypeBase):
     __tablename__ = "message_agent_thoughts"
     __table_args__ = (
@@ -2644,6 +2673,38 @@ class MessageAgentThought(TypeBase):
             else:
                 return {}
 
+    def _per_call(self, values_by_tool: dict[str, Any]) -> list[Any]:
+        """
+        Spread a tool-name-keyed payload over the turn's calls, in call order.
+
+        One entry per entry in ``tools``, so a tool called twice gets two, each
+        holding that call's own value. A name whose stored value is not one
+        value per call — every record written before those calls were kept
+        apart — gives the same value to each of its calls, which is what those
+        records mean.
+        """
+        occurrences = Counter(self.tools)
+        seen: Counter[str] = Counter()
+        per_call: list[Any] = []
+        for tool in self.tools:
+            occurrence = seen[tool]
+            seen[tool] += 1
+            per_call.append(_select_tool_occurrence(values_by_tool.get(tool, {}), occurrence, occurrences[tool]))
+
+        return per_call
+
+    @property
+    def tool_inputs_per_call(self) -> list[Any]:
+        return self._per_call(self.tool_inputs_dict)
+
+    @property
+    def tool_outputs_per_call(self) -> list[Any]:
+        return self._per_call(self.tool_outputs_dict)
+
+    @property
+    def tool_metas_per_call(self) -> list[Any]:
+        return self._per_call(self.tool_meta)
+
 
 class DatasetRetrieverResource(TypeBase):
     __tablename__ = "dataset_retriever_resources"
diff --git a/api/services/agent_service.py b/api/services/agent_service.py
index e065e1f978b..8671aabc11e 100644
--- a/api/services/agent_service.py
+++ b/api/services/agent_service.py
@@ -95,16 +95,16 @@ class AgentService:
         for agent_thought in agent_thoughts:
             tools = agent_thought.tools
             tool_labels = agent_thought.tool_labels
-            tool_meta = agent_thought.tool_meta
-            tool_inputs = agent_thought.tool_inputs_dict
-            tool_outputs = agent_thought.tool_outputs_dict or {}
+            # one entry per call, in call order, so a tool called twice in a turn
+            # gets a log entry per call instead of one call's data twice
+            tool_inputs = agent_thought.tool_inputs_per_call
+            tool_outputs = agent_thought.tool_outputs_per_call
+            tool_metas = agent_thought.tool_metas_per_call
             tool_calls = []
-            for tool in tools:
-                tool_name = tool
+            for tool_name, tool_input, tool_output, tool_meta_data in zip(
+                tools, tool_inputs, tool_outputs, tool_metas, strict=True
+            ):
                 tool_label = tool_labels.get(tool_name, tool_name)
-                tool_input = tool_inputs.get(tool_name, {})
-                tool_output = tool_outputs.get(tool_name, {})
-                tool_meta_data = tool_meta.get(tool_name, {})
                 tool_config = tool_meta_data.get("tool_config", {})
                 tool_provider_type = tool_config.get("tool_provider_type", "")
                 tool_provider_id = tool_config.get("tool_provider", "")
diff --git a/api/tests/unit_tests/core/agent/test_base_agent_runner.py b/api/tests/unit_tests/core/agent/test_base_agent_runner.py
index 7411164512c..b7fd1037fdc 100644
--- a/api/tests/unit_tests/core/agent/test_base_agent_runner.py
+++ b/api/tests/unit_tests/core/agent/test_base_agent_runner.py
@@ -668,3 +668,116 @@ class TestBaseAgentRunnerCoverage:
         result = runner.organize_agent_history([], session=mock_db_session)
 
         assert any(isinstance(item, module.ToolPromptMessage) for item in result)
+
+
+# ==========================================================
+# organize_agent_history — a tool called more than once in a turn
+# ==========================================================
+
+
+class TestOrganizeHistoryRepeatedTools:
+    def _replay(self, runner: BaseAgentRunner, mock_db_session, mocker: MockerFixture, thought):
+        msg = mocker.MagicMock(id="m_repeat", agent_thoughts=[thought], answer=None, app_model_config=None)
+        msg.agent_thoughts_with_session.return_value = [thought]
+
+        mock_db_session.execute.return_value.scalars.return_value.all.return_value = [msg]
+        mocker.patch.object(module, "extract_thread_messages", return_value=[msg])
+        mocker.patch.object(
+            runner,
+            "organize_agent_user_prompt",
+            return_value=module.UserPromptMessage(content="user"),
+        )
+
+        result = runner.organize_agent_history([], session=mock_db_session)
+
+        assistant = next(item for item in result if isinstance(item, module.AssistantPromptMessage) and item.tool_calls)
+        responses = [item for item in result if isinstance(item, module.ToolPromptMessage)]
+        return assistant, responses
+
+    def test_repeated_tool_replays_each_call_separately(
+        self, runner: BaseAgentRunner, mock_db_session, mocker: MockerFixture
+    ):
+        thought = mocker.MagicMock(
+            tool="search;search",
+            tool_input=json.dumps({"search": [{"q": "first"}, {"q": "second"}]}),
+            observation=json.dumps({"search": ["first result", "second result"]}),
+            thought="thinking",
+        )
+
+        assistant, responses = self._replay(runner, mock_db_session, mocker, thought)
+
+        assert [call.function.name for call in assistant.tool_calls] == ["search", "search"]
+        assert [json.loads(call.function.arguments) for call in assistant.tool_calls] == [
+            {"q": "first"},
+            {"q": "second"},
+        ]
+        assert [response.content for response in responses] == ["first result", "second result"]
+        # each replayed response is tied to its own call
+        assert [call.id for call in assistant.tool_calls] == [response.tool_call_id for response in responses]
+        assert len({call.id for call in assistant.tool_calls}) == 2
+
+    def test_legacy_record_replays_unchanged(self, runner: BaseAgentRunner, mock_db_session, mocker: MockerFixture):
+        # exactly the shape written before repeated calls were kept apart: one
+        # value per tool name, the last call having overwritten the first
+        thought = mocker.MagicMock(
+            tool="search;search",
+            tool_input=json.dumps({"search": {"q": "second"}}),
+            observation=json.dumps({"search": "second result"}),
+            thought="thinking",
+        )
+
+        assistant, responses = self._replay(runner, mock_db_session, mocker, thought)
+
+        assert [json.loads(call.function.arguments) for call in assistant.tool_calls] == [
+            {"q": "second"},
+            {"q": "second"},
+        ]
+        assert [response.content for response in responses] == ["second result", "second result"]
+
+    def test_single_call_replays_unchanged(self, runner: BaseAgentRunner, mock_db_session, mocker: MockerFixture):
+        thought = mocker.MagicMock(
+            tool="search",
+            tool_input=json.dumps({"search": {"q": "only"}}),
+            observation=json.dumps({"search": "only result"}),
+            thought="thinking",
+        )
+
+        assistant, responses = self._replay(runner, mock_db_session, mocker, thought)
+
+        assert len(assistant.tool_calls) == 1
+        assert json.loads(assistant.tool_calls[0].function.arguments) == {"q": "only"}
+        assert [response.content for response in responses] == ["only result"]
+
+    def test_distinct_tools_replay_unchanged(self, runner: BaseAgentRunner, mock_db_session, mocker: MockerFixture):
+        thought = mocker.MagicMock(
+            tool="search;calculator",
+            tool_input=json.dumps({"search": {"q": "a"}, "calculator": {"expr": "1+1"}}),
+            observation=json.dumps({"search": "search result", "calculator": "2"}),
+            thought="thinking",
+        )
+
+        assistant, responses = self._replay(runner, mock_db_session, mocker, thought)
+
+        assert [call.function.name for call in assistant.tool_calls] == ["search", "calculator"]
+        assert [response.content for response in responses] == ["search result", "2"]
+
+    def test_a_legacy_list_of_matching_length_is_read_per_call_not_whole(
+        self, runner: BaseAgentRunner, mock_db_session, mocker: MockerFixture
+    ):
+        # the other half of the same decision. Length is the only signal the
+        # reader has, so a single stored value that is itself a list as long as
+        # the call count is indistinguishable from one value per call, and is
+        # read as one value per call. A legacy row whose one value happened to
+        # be a two-element list is therefore split across the two calls instead
+        # of replayed whole.
+        thought = mocker.MagicMock(
+            tool="search;search",
+            tool_input=json.dumps({"search": ["a", "b"]}),
+            observation=json.dumps({"search": ["x", "y"]}),
+            thought="thinking",
+        )
+
+        assistant, responses = self._replay(runner, mock_db_session, mocker, thought)
+
+        assert [json.loads(call.function.arguments) for call in assistant.tool_calls] == ["a", "b"]
+        assert [response.content for response in responses] == ["x", "y"]
diff --git a/api/tests/unit_tests/core/agent/test_fc_agent_runner.py b/api/tests/unit_tests/core/agent/test_fc_agent_runner.py
index ea8c3b87c42..33ff0c237f1 100644
--- a/api/tests/unit_tests/core/agent/test_fc_agent_runner.py
+++ b/api/tests/unit_tests/core/agent/test_fc_agent_runner.py
@@ -574,3 +574,133 @@ class TestRunMethod:
 
         with pytest.raises(AgentMaxIterationError):
             list(runner.run(runner.session, message, "query"))
+
+
+# ==============================
+# Repeated Tool Calls In One Turn
+# ==============================
+
+
+def _make_tool_call(call_id: str, name: str, arguments: dict[str, Any]) -> MagicMock:
+    tool_call = MagicMock()
+    tool_call.id = call_id
+    tool_call.function.name = name
+    tool_call.function.arguments = json.dumps(arguments)
+    return tool_call
+
+
+def _run_one_turn(runner: FunctionCallAgentRunner, mocker: MockerFixture, tool_calls, responses, metas=None):
+    """Drive one tool-calling iteration followed by a plain answer."""
+    result = DummyResult(message=DummyMessage(content="", tool_calls=tool_calls), usage=build_usage())
+    final_result = DummyResult(message=DummyMessage(content="done", tool_calls=[]), usage=build_usage())
+    runner.model_instance.invoke_llm.side_effect = [result, final_result]
+
+    names = {tool_call.function.name for tool_call in tool_calls}
+    prompt_tools = []
+    instances = {}
+    for name in names:
+        prompt_tool = MagicMock()
+        prompt_tool.name = name
+        prompt_tools.append(prompt_tool)
+        instances[name] = MagicMock()
+    runner._init_prompt_tools.return_value = (instances, prompt_tools)
+
+    invoke_metas = []
+    for meta in metas or [{"ok": True} for _ in responses]:
+        tool_invoke_meta = MagicMock()
+        tool_invoke_meta.to_dict.return_value = meta
+        invoke_metas.append(tool_invoke_meta)
+    mocker.patch(
+        "core.agent.fc_agent_runner.ToolEngine.agent_invoke",
+        side_effect=[
+            (response, [], tool_invoke_meta) for response, tool_invoke_meta in zip(responses, invoke_metas, strict=True)
+        ],
+    )
+
+    list(runner.run(runner.session, MagicMock(id="m1"), "query"))
+
+
+def _saved_tool_input(runner: FunctionCallAgentRunner) -> dict[str, Any]:
+    for call in runner.save_agent_thought.call_args_list:
+        if call.kwargs.get("tool_name"):
+            return json.loads(call.kwargs["tool_input"])
+    raise AssertionError("no agent thought was saved with tool input")
+
+
+def _saved_observation(runner: FunctionCallAgentRunner) -> dict[str, Any]:
+    for call in runner.save_agent_thought.call_args_list:
+        observation = call.kwargs.get("observation")
+        if observation:
+            return observation
+    raise AssertionError("no agent thought was saved with an observation")
+
+
+def _saved_tool_invoke_meta(runner: FunctionCallAgentRunner) -> dict[str, Any]:
+    for call in runner.save_agent_thought.call_args_list:
+        tool_invoke_meta = call.kwargs.get("tool_invoke_meta")
+        if tool_invoke_meta:
+            return tool_invoke_meta
+    raise AssertionError("no agent thought was saved with tool invoke meta")
+
+
+class TestRepeatedToolCalls:
+    def test_repeated_tool_keeps_every_input_and_observation(
+        self, runner: FunctionCallAgentRunner, mocker: MockerFixture
+    ):
+        _run_one_turn(
+            runner,
+            mocker,
+            tool_calls=[
+                _make_tool_call("1", "search", {"q": "first"}),
+                _make_tool_call("2", "search", {"q": "second"}),
+            ],
+            responses=["first result", "second result"],
+        )
+
+        assert _saved_tool_input(runner) == {"search": [{"q": "first"}, {"q": "second"}]}
+        assert _saved_observation(runner) == {"search": ["first result", "second result"]}
+
+    def test_repeated_tool_keeps_every_invoke_meta(self, runner: FunctionCallAgentRunner, mocker: MockerFixture):
+        # the agent log reads a provider, a duration and an error out of the meta
+        # for each call it displays, so a repeated tool needs one meta per call
+        _run_one_turn(
+            runner,
+            mocker,
+            tool_calls=[
+                _make_tool_call("1", "search", {"q": "first"}),
+                _make_tool_call("2", "search", {"q": "second"}),
+            ],
+            responses=["first result", "second result"],
+            metas=[{"time_cost": 1}, {"time_cost": 2}],
+        )
+
+        assert _saved_tool_invoke_meta(runner) == {"search": [{"time_cost": 1}, {"time_cost": 2}]}
+
+    def test_single_call_keeps_the_legacy_shape(self, runner: FunctionCallAgentRunner, mocker: MockerFixture):
+        _run_one_turn(
+            runner,
+            mocker,
+            tool_calls=[_make_tool_call("1", "search", {"q": "only"})],
+            responses=["only result"],
+            metas=[{"time_cost": 1}],
+        )
+
+        assert _saved_tool_input(runner) == {"search": {"q": "only"}}
+        assert _saved_observation(runner) == {"search": "only result"}
+        assert _saved_tool_invoke_meta(runner) == {"search": {"time_cost": 1}}
+
+    def test_distinct_tools_keep_the_legacy_shape(self, runner: FunctionCallAgentRunner, mocker: MockerFixture):
+        _run_one_turn(
+            runner,
+            mocker,
+            tool_calls=[
+                _make_tool_call("1", "search", {"q": "a"}),
+                _make_tool_call("2", "calculator", {"expr": "1+1"}),
+            ],
+            responses=["search result", "2"],
+            metas=[{"time_cost": 1}, {"time_cost": 2}],
+        )
+
+        assert _saved_tool_input(runner) == {"search": {"q": "a"}, "calculator": {"expr": "1+1"}}
+        assert _saved_observation(runner) == {"search": "search result", "calculator": "2"}
+        assert _saved_tool_invoke_meta(runner) == {"search": {"time_cost": 1}, "calculator": {"time_cost": 2}}
diff --git a/api/tests/unit_tests/core/ops/test_ops_trace_manager.py b/api/tests/unit_tests/core/ops/test_ops_trace_manager.py
index 3c3011597f0..77d65062f50 100644
--- a/api/tests/unit_tests/core/ops/test_ops_trace_manager.py
+++ b/api/tests/unit_tests/core/ops/test_ops_trace_manager.py
@@ -538,6 +538,28 @@ def test_tool_trace_reads_real_message_file(monkeypatch: pytest.MonkeyPatch, dat
     assert result.message_file_data.id == file.id
 
 
+def test_tool_trace_reads_the_last_call_of_a_repeated_tool(monkeypatch: pytest.MonkeyPatch, database: Session) -> None:
+    # a tool called twice in one turn keeps one meta per call; the trace covers
+    # the tool rather than one call of it, so it reads the last — the only one a
+    # record written before those calls were kept apart held
+    thought = SimpleNamespace(
+        tools=["tool-a", "tool-a"],
+        created_at=datetime(2025, 2, 20, 12, 1),
+        tool_meta={
+            "tool-a": [
+                {"tool_config": {}, "time_cost": 3, "error": "", "tool_parameters": {"q": "first"}},
+                {"tool_config": {}, "time_cost": 5, "error": "", "tool_parameters": {"q": "second"}},
+            ]
+        },
+    )
+    monkeypatch.setattr(module, "get_message_data", lambda _message_id: _message_data(agent_thoughts=[thought]))
+    result = TraceTask(trace_type=TraceTaskName.TOOL_TRACE).tool_trace(
+        "message-1", {"start": 1, "end": 2}, tool_name="tool-a", tool_inputs={}, tool_outputs="result"
+    )
+    assert result.time_cost == 5
+    assert result.tool_parameters == {"q": "second"}
+
+
 def test_node_execution_trace_resolves_real_message_by_conversation_and_run(
     trace_environment: None, database: Session
 ) -> None:
diff --git a/api/tests/unit_tests/models/test_model.py b/api/tests/unit_tests/models/test_model.py
index bb3206713d7..8810a910b9c 100644
--- a/api/tests/unit_tests/models/test_model.py
+++ b/api/tests/unit_tests/models/test_model.py
@@ -1,4 +1,5 @@
 import importlib
+import json
 import types
 from unittest.mock import MagicMock, patch
 
@@ -6,7 +7,8 @@ import pytest
 
 from core.workflow.file_reference import build_file_reference
 from graphon.file import FILE_MODEL_IDENTITY, FileTransferMethod
-from models.model import Conversation, Message
+from models.enums import CreatorUserRole
+from models.model import Conversation, Message, MessageAgentThought
 
 
 @pytest.fixture(autouse=True)
@@ -138,3 +140,134 @@ def test_message_inputs_resolve_file_tenant_with_caller_session() -> None:
 
     assert inputs["file"] == "tenant-1"
     session.scalar.assert_called_once()
+
+
+# ==========================================================
+# MessageAgentThought — one payload per call, in call order
+# ==========================================================
+
+
+def _agent_thought(*, tool: str, tool_input: str, observation: str, tool_meta_str: str) -> MessageAgentThought:
+    return MessageAgentThought(
+        message_id="message-1",
+        position=1,
+        created_by_role=CreatorUserRole.ACCOUNT,
+        created_by="account-1",
+        tool=tool,
+        tool_input=tool_input,
+        observation=observation,
+        tool_meta_str=tool_meta_str,
+    )
+
+
+# the four shapes an agent log can be built from: a record written before
+# repeated calls were kept apart, and one written after, each with the tool
+# called once and called twice. The legacy pair are written as literals — they
+# are rows that exist and cannot be migrated.
+LEGACY_SINGLE = _agent_thought(
+    tool="search",
+    tool_input=json.dumps({"search": {"q": "only"}}),
+    observation=json.dumps({"search": "only result"}),
+    tool_meta_str=json.dumps({"search": {"time_cost": 1}}),
+)
+LEGACY_REPEATED = _agent_thought(
+    tool="search;search",
+    tool_input=json.dumps({"search": {"q": "second"}}),
+    observation=json.dumps({"search": "second result"}),
+    tool_meta_str=json.dumps({"search": {"time_cost": 2}}),
+)
+NEW_SINGLE = _agent_thought(
+    tool="search",
+    tool_input=json.dumps({"search": {"q": "only"}}),
+    observation=json.dumps({"search": "only result"}),
+    tool_meta_str=json.dumps({"search": {"time_cost": 1}}),
+)
+NEW_REPEATED = _agent_thought(
+    tool="search;search",
+    tool_input=json.dumps({"search": [{"q": "first"}, {"q": "second"}]}),
+    observation=json.dumps({"search": ["first result", "second result"]}),
+    tool_meta_str=json.dumps({"search": [{"time_cost": 1}, {"time_cost": 2}]}),
+)
+
+
+def test_legacy_single_call_reads_one_value_per_payload():
+    assert LEGACY_SINGLE.tool_inputs_per_call == [{"q": "only"}]
+    assert LEGACY_SINGLE.tool_outputs_per_call == ["only result"]
+    assert LEGACY_SINGLE.tool_metas_per_call == [{"time_cost": 1}]
+
+
+def test_legacy_repeated_call_replays_the_surviving_value_for_each_call():
+    # the row only ever held one call's data; both entries show it, exactly as
+    # they do without this change
+    assert LEGACY_REPEATED.tool_inputs_per_call == [{"q": "second"}, {"q": "second"}]
+    assert LEGACY_REPEATED.tool_outputs_per_call == ["second result", "second result"]
+    assert LEGACY_REPEATED.tool_metas_per_call == [{"time_cost": 2}, {"time_cost": 2}]
+
+
+def test_new_single_call_reads_identically_to_a_legacy_single_call():
+    assert NEW_SINGLE.tool_inputs_per_call == LEGACY_SINGLE.tool_inputs_per_call
+    assert NEW_SINGLE.tool_outputs_per_call == LEGACY_SINGLE.tool_outputs_per_call
+    assert NEW_SINGLE.tool_metas_per_call == LEGACY_SINGLE.tool_metas_per_call
+
+
+def test_new_repeated_call_reads_each_call_separately():
+    assert NEW_REPEATED.tool_inputs_per_call == [{"q": "first"}, {"q": "second"}]
+    assert NEW_REPEATED.tool_outputs_per_call == ["first result", "second result"]
+    assert NEW_REPEATED.tool_metas_per_call == [{"time_cost": 1}, {"time_cost": 2}]
+
+
+def test_distinct_tools_read_one_value_each():
+    thought = _agent_thought(
+        tool="search;calculator",
+        tool_input=json.dumps({"search": {"q": "a"}, "calculator": {"expr": "1+1"}}),
+        observation=json.dumps({"search": "search result", "calculator": "2"}),
+        tool_meta_str=json.dumps({"search": {"time_cost": 1}, "calculator": {"time_cost": 2}}),
+    )
+
+    assert thought.tool_inputs_per_call == [{"q": "a"}, {"expr": "1+1"}]
+    assert thought.tool_outputs_per_call == ["search result", "2"]
+    assert thought.tool_metas_per_call == [{"time_cost": 1}, {"time_cost": 2}]
+
+
+def test_a_stored_list_that_is_not_one_value_per_call_is_replayed_whole():
+    # the reader tells a per-call list from a single call's list value by length
+    # alone; a length that does not match the call count is not per-call data
+    thought = _agent_thought(
+        tool="search;search",
+        tool_input=json.dumps({"search": ["a", "b", "c"]}),
+        observation=json.dumps({"search": ["x", "y", "z"]}),
+        tool_meta_str=json.dumps({"search": {"time_cost": 1}}),
+    )
+
+    assert thought.tool_inputs_per_call == [["a", "b", "c"], ["a", "b", "c"]]
+    assert thought.tool_outputs_per_call == [["x", "y", "z"], ["x", "y", "z"]]
+
+
+def test_a_legacy_list_of_matching_length_is_read_per_call_not_whole():
+    # the other half of the same decision. Length is the only signal the reader
+    # has, so a single stored value that is itself a list as long as the call
+    # count is indistinguishable from one value per call, and is read as one
+    # value per call. A legacy row whose one value happened to be a two-element
+    # list is therefore split across the two calls instead of replayed whole.
+    thought = _agent_thought(
+        tool="search;search",
+        tool_input=json.dumps({"search": ["a", "b"]}),
+        observation=json.dumps({"search": ["x", "y"]}),
+        tool_meta_str=json.dumps({"search": {"time_cost": 1}}),
+    )
+
+    assert thought.tool_inputs_per_call == ["a", "b"]
+    assert thought.tool_outputs_per_call == ["x", "y"]
+
+
+def test_a_tool_missing_from_the_payload_reads_empty():
+    thought = _agent_thought(
+        tool="search;calculator",
+        tool_input=json.dumps({"search": {"q": "a"}}),
+        observation=json.dumps({"search": "search result"}),
+        tool_meta_str="{}",
+    )
+
+    assert thought.tool_inputs_per_call == [{"q": "a"}, {}]
+    assert thought.tool_outputs_per_call == ["search result", {}]
+    assert thought.tool_metas_per_call == [{}, {}]
diff --git a/api/tests/unit_tests/services/test_agent_service.py b/api/tests/unit_tests/services/test_agent_service.py
new file mode 100644
index 00000000000..e4e7b04c0ee
--- /dev/null
+++ b/api/tests/unit_tests/services/test_agent_service.py
@@ -0,0 +1,128 @@
+import json
+from datetime import UTC, datetime
+from typing import TypedDict, cast
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from models.account import Account
+from models.enums import CreatorUserRole
+from models.model import MessageAgentThought
+from services.agent_service import AgentService
+
+
+class _Iteration(TypedDict):
+    tool_calls: list[dict[str, object]]
+
+
+class _AgentLogs(TypedDict):
+    iterations: list[_Iteration]
+
+
+def _agent_thought(*, tool: str, tool_input: str, observation: str, tool_meta_str: str) -> MessageAgentThought:
+    thought = MessageAgentThought(
+        message_id="message-1",
+        position=1,
+        created_by_role=CreatorUserRole.ACCOUNT,
+        created_by="account-1",
+        tool=tool,
+        tool_input=tool_input,
+        observation=observation,
+        tool_meta_str=tool_meta_str,
+        tool_labels_str=json.dumps({"search": {"en_US": "Search"}}),
+    )
+    thought.created_at = datetime(2026, 8, 5, tzinfo=UTC)
+    thought.tokens = 10
+    return thought
+
+
+def _get_agent_logs(agent_thought: MessageAgentThought) -> _AgentLogs:
+    app_model = MagicMock(id="app-1", tenant_id="tenant-1")
+    session = MagicMock()
+    conversation = MagicMock(from_end_user_id=None, from_account_id="account-1")
+    message = MagicMock(provider_response_latency=1.5, answer_tokens=1, message_tokens=2)
+    message.agent_thoughts_with_session.return_value = [agent_thought]
+    session.scalar.side_effect = [conversation, message, "Executor"]
+
+    with (
+        patch("services.agent_service.current_user", MagicMock(spec=Account, timezone="UTC")),
+        patch("services.agent_service.load_annotation_reply_config", return_value=None),
+        patch("services.agent_service.AgentConfigManager.convert", return_value=MagicMock(tools=[])),
+        patch("services.agent_service.ToolManager.get_tool_icon", return_value="icon"),
+    ):
+        return cast(_AgentLogs, AgentService.get_agent_logs(app_model, "conversation-1", "message-1", session))
+
+
+@pytest.fixture
+def legacy_repeated() -> MessageAgentThought:
+    # written before repeated calls were kept apart: the second call's data
+    # overwrote the first, and the row holds one value for the tool name
+    return _agent_thought(
+        tool="search;search",
+        tool_input=json.dumps({"search": {"q": "second"}}),
+        observation=json.dumps({"search": "second result"}),
+        tool_meta_str=json.dumps({"search": {"time_cost": 2, "tool_config": {"tool_provider_type": "builtin"}}}),
+    )
+
+
+def test_repeated_tool_renders_one_log_entry_per_call() -> None:
+    thought = _agent_thought(
+        tool="search;search",
+        tool_input=json.dumps({"search": [{"q": "first"}, {"q": "second"}]}),
+        observation=json.dumps({"search": ["first result", "second result"]}),
+        tool_meta_str=json.dumps(
+            {
+                "search": [
+                    {"time_cost": 1, "tool_config": {"tool_provider_type": "builtin", "tool_provider": "a"}},
+                    {"time_cost": 2, "tool_config": {"tool_provider_type": "api", "tool_provider": "b"}},
+                ]
+            }
+        ),
+    )
+
+    tool_calls = _get_agent_logs(thought)["iterations"][0]["tool_calls"]
+
+    assert [call["tool_name"] for call in tool_calls] == ["search", "search"]
+    assert [call["tool_input"] for call in tool_calls] == [{"q": "first"}, {"q": "second"}]
+    assert [call["tool_output"] for call in tool_calls] == ["first result", "second result"]
+    assert [call["time_cost"] for call in tool_calls] == [1, 2]
+
+
+def test_legacy_repeated_tool_renders_exactly_as_it_did(legacy_repeated: MessageAgentThought) -> None:
+    tool_calls = _get_agent_logs(legacy_repeated)["iterations"][0]["tool_calls"]
+
+    assert [call["tool_name"] for call in tool_calls] == ["search", "search"]
+    assert [call["tool_input"] for call in tool_calls] == [{"q": "second"}, {"q": "second"}]
+    assert [call["tool_output"] for call in tool_calls] == ["second result", "second result"]
+    assert [call["time_cost"] for call in tool_calls] == [2, 2]
+
+
+def test_single_call_renders_one_entry() -> None:
+    thought = _agent_thought(
+        tool="search",
+        tool_input=json.dumps({"search": {"q": "only"}}),
+        observation=json.dumps({"search": "only result"}),
+        tool_meta_str=json.dumps({"search": {"time_cost": 1, "tool_config": {"tool_provider_type": "builtin"}}}),
+    )
+
+    tool_calls = _get_agent_logs(thought)["iterations"][0]["tool_calls"]
+
+    assert len(tool_calls) == 1
+    assert tool_calls[0]["tool_input"] == {"q": "only"}
+    assert tool_calls[0]["tool_output"] == "only result"
+    assert tool_calls[0]["time_cost"] == 1
+
+
+def test_distinct_tools_render_their_own_payloads() -> None:
+    thought = _agent_thought(
+        tool="search;calculator",
+        tool_input=json.dumps({"search": {"q": "a"}, "calculator": {"expr": "1+1"}}),
+        observation=json.dumps({"search": "search result", "calculator": "2"}),
+        tool_meta_str=json.dumps({"search": {"time_cost": 1}, "calculator": {"time_cost": 2}}),
+    )
+
+    tool_calls = _get_agent_logs(thought)["iterations"][0]["tool_calls"]
+
+    assert [call["tool_name"] for call in tool_calls] == ["search", "calculator"]
+    assert [call["tool_input"] for call in tool_calls] == [{"q": "a"}, {"expr": "1+1"}]
+    assert [call["tool_output"] for call in tool_calls] == ["search result", "2"]