make all_messages() a method

preview.README.md

@@ -62,5 +62,5 @@ print(result.response)
 
 # `result.all_messages` includes details of messages exchanged, useful if you want to continue
 # the conversation later, via the `message_history` argument of `run_sync`.
-print(result.all_messages)
+print(result.all_messages())
 ```

pydantic_ai/agent.py

@@ -139,7 +139,7 @@ async def run(
                             run_span.set_attribute('cost', cost)
                             handle_span.set_attribute('result', left.value)
                             handle_span.message = 'handle model response -> final result'
-                            return shared.RunResult(left.value, messages, new_message_index, cost)
+                            return shared.RunResult(left.value, cost, messages, new_message_index)
                         else:
                             tool_responses = either.right
                             handle_span.set_attribute('tool_responses', tool_responses)

pydantic_ai/shared.py

@@ -58,20 +58,25 @@ class RunResult(Generic[ResultData]):
     """Result of a run."""
 
     response: ResultData
-    all_messages: list[messages.Message]
-    new_message_index: int
     cost: Cost
+    _all_messages: list[messages.Message]
+    _new_message_index: int
+
+    def all_messages(self) -> list[messages.Message]:
+        """Return the history of messages."""
+        # this is a method to be consistent with the other methods
+        return self._all_messages
 
     def all_messages_json(self) -> bytes:
         """Return the history of messages as JSON bytes."""
-        return messages.MessagesTypeAdapter.dump_json(self.all_messages)
+        return messages.MessagesTypeAdapter.dump_json(self.all_messages())
 
     def new_messages(self) -> list[messages.Message]:
         """Return new messages associated with this run.
 
         System prompts and any messages from older runs are excluded.
         """
-        return self.all_messages[self.new_message_index :]
+        return self.all_messages()[self._new_message_index :]
 
     def new_messages_json(self) -> bytes:
         """Return new messages from [new_messages][] as JSON bytes."""

pydantic_ai_examples/chat_app.py

@@ -39,7 +39,7 @@ async def stream_messages():
         database.add_messages(response.new_messages_json())
         # stream the last message which will be the agent response, we can't just yield `new_messages_json()`
         # since we already stream the user prompt
-        yield MessageTypeAdapter.dump_json(response.all_messages[-1]) + b'\n'
+        yield MessageTypeAdapter.dump_json(response.all_messages()[-1]) + b'\n'
 
     return StreamingResponse(stream_messages(), media_type='text/plain')
 

tests/models/test_gemini.py

@@ -360,7 +360,7 @@ async def test_request_simple_success(get_gemini_client: GetGeminiClient):
 
     result = await agent.run('Hello')
     assert result.response == 'Hello world'
-    assert result.all_messages == snapshot(
+    assert result.all_messages() == snapshot(
         [
             UserPrompt(content='Hello', timestamp=IsNow(tz=timezone.utc)),
             LLMResponse(content='Hello world', timestamp=IsNow(tz=timezone.utc)),
@@ -381,7 +381,7 @@ async def test_request_structured_response(get_gemini_client: GetGeminiClient):
 
     result = await agent.run('Hello')
     assert result.response == [1, 2, 123]
-    assert result.all_messages == snapshot(
+    assert result.all_messages() == snapshot(
         [
             UserPrompt(content='Hello', timestamp=IsNow(tz=timezone.utc)),
             LLMToolCalls(
@@ -424,7 +424,7 @@ async def get_location(loc_name: str) -> str:
 
     result = await agent.run('Hello')
     assert result.response == 'final response'
-    assert result.all_messages == snapshot(
+    assert result.all_messages() == snapshot(
         [
             SystemPrompt(content='this is the system prompt'),
             UserPrompt(content='Hello', timestamp=IsNow(tz=timezone.utc)),

tests/models/test_model_function.py

@@ -37,7 +37,7 @@ def test_simple():
     agent = Agent(FunctionModel(return_last), deps=None)
     result = agent.run_sync('Hello')
     assert result.response == snapshot("content='Hello' role='user' message_count=1")
-    assert result.all_messages == snapshot(
+    assert result.all_messages() == snapshot(
         [
             UserPrompt(
                 content='Hello',
@@ -52,9 +52,9 @@ def test_simple():
         ]
     )
 
-    result2 = agent.run_sync('World', message_history=result.all_messages)
+    result2 = agent.run_sync('World', message_history=result.all_messages())
     assert result2.response == snapshot("content='World' role='user' message_count=3")
-    assert result2.all_messages == snapshot(
+    assert result2.all_messages() == snapshot(
         [
             UserPrompt(
                 content='Hello',
@@ -127,7 +127,7 @@ async def get_weather(_: CallContext[None], lat: int, lng: int):
 def test_weather():
     result = weather_agent.run_sync('London')
     assert result.response == 'Raining in London'
-    assert result.all_messages == snapshot(
+    assert result.all_messages() == snapshot(
         [
             UserPrompt(
                 content='London',
@@ -322,7 +322,7 @@ def f(messages: list[Message], info: AgentInfo) -> LLMMessage:
 def test_call_all():
     result = agent_all.run_sync('Hello', model=TestModel())
     assert result.response == snapshot('{"foo":"1","bar":"2","baz":"3","qux":"4","quz":"a"}')
-    assert result.all_messages == snapshot(
+    assert result.all_messages() == snapshot(
         [
             SystemPrompt(content='foobar'),
             UserPrompt(content='Hello', timestamp=IsNow(tz=timezone.utc)),

tests/models/test_model_test.py

@@ -82,7 +82,7 @@ async def my_ret(x: int) -> str:
     result = agent.run_sync('Hello', model=TestModel())
     assert call_count == 2
     assert result.response == snapshot('{"my_ret":"1"}')
-    assert result.all_messages == snapshot(
+    assert result.all_messages() == snapshot(
         [
             UserPrompt(content='Hello', timestamp=IsNow(tz=timezone.utc)),
             LLMToolCalls(

tests/models/test_openai.py

@@ -113,7 +113,7 @@ async def test_request_structured_response():
 
     result = await agent.run('Hello')
     assert result.response == [1, 2, 123]
-    assert result.all_messages == snapshot(
+    assert result.all_messages() == snapshot(
         [
             UserPrompt(content='Hello', timestamp=IsNow(tz=datetime.timezone.utc)),
             LLMToolCalls(
@@ -185,7 +185,7 @@ async def get_location(loc_name: str) -> str:
 
     result = await agent.run('Hello')
     assert result.response == 'final response'
-    assert result.all_messages == snapshot(
+    assert result.all_messages() == snapshot(
         [
             SystemPrompt(content='this is the system prompt'),
             UserPrompt(content='Hello', timestamp=IsNow(tz=datetime.timezone.utc)),

tests/test_agent.py

@@ -70,7 +70,7 @@ def return_model(messages: list[Message], info: AgentInfo) -> LLMMessage:
     result = agent.run_sync('Hello')
     assert isinstance(result.response, Foo)
     assert result.response.model_dump() == {'a': 42, 'b': 'foo'}
-    assert result.all_messages == snapshot(
+    assert result.all_messages() == snapshot(
         [
             UserPrompt(content='Hello', timestamp=IsNow(tz=timezone.utc)),
             LLMToolCalls(
@@ -120,7 +120,7 @@ def validate_result(ctx: CallContext[None], r: Foo) -> Foo:
     result = agent.run_sync('Hello')
     assert isinstance(result.response, Foo)
     assert result.response.model_dump() == {'a': 42, 'b': 'foo'}
-    assert result.all_messages == snapshot(
+    assert result.all_messages() == snapshot(
         [
             UserPrompt(content='Hello', timestamp=IsNow(tz=timezone.utc)),
             LLMToolCalls(
@@ -153,7 +153,7 @@ def return_tuple(_: list[Message], info: AgentInfo) -> LLMMessage:
     result = agent.run_sync('Hello')
     assert result.response == ('foo', 'bar')
     assert call_index == 2
-    assert result.all_messages == snapshot(
+    assert result.all_messages() == snapshot(
         [
             UserPrompt(content='Hello', timestamp=IsNow(tz=timezone.utc)),
             LLMResponse(content='hello', timestamp=IsNow(tz=timezone.utc)),
@@ -355,7 +355,7 @@ def validate_result(ctx: CallContext[None], r: Any) -> Any:
     assert got_tool_call_name == snapshot('final_result_Bar')
 
 
-def test_run_with_history():
+def test_run_with_history_new():
     m = TestModel()
 
     agent = Agent(m, deps=None, system_prompt='Foobar')
@@ -364,11 +364,25 @@ def test_run_with_history():
     async def ret_a(x: str) -> str:
         return f'{x}-apple'
 
-    result = agent.run_sync('Hello')
-    assert result == snapshot(
+    result1 = agent.run_sync('Hello')
+    assert result1.new_messages() == snapshot(
+        [
+            UserPrompt(content='Hello', timestamp=IsNow(tz=timezone.utc)),
+            LLMToolCalls(
+                calls=[ToolCall(tool_name='ret_a', args=ArgsObject(args_object={'x': 'a'}))],
+                timestamp=IsNow(tz=timezone.utc),
+            ),
+            ToolReturn(tool_name='ret_a', content='a-apple', timestamp=IsNow(tz=timezone.utc)),
+            LLMResponse(content='{"ret_a":"a-apple"}', timestamp=IsNow(tz=timezone.utc)),
+        ]
+    )
+
+    # if we pass new_messages, system prompt is inserted before the message_history messages
+    result2 = agent.run_sync('Hello again', message_history=result1.new_messages())
+    assert result2 == snapshot(
         RunResult(
             response='{"ret_a":"a-apple"}',
-            all_messages=[
+            _all_messages=[
                 SystemPrompt(content='Foobar'),
                 UserPrompt(content='Hello', timestamp=IsNow(tz=timezone.utc)),
                 LLMToolCalls(
@@ -377,17 +391,31 @@ async def ret_a(x: str) -> str:
                 ),
                 ToolReturn(tool_name='ret_a', content='a-apple', timestamp=IsNow(tz=timezone.utc)),
                 LLMResponse(content='{"ret_a":"a-apple"}', timestamp=IsNow(tz=timezone.utc)),
+                # second call, notice no repeated system prompt
+                UserPrompt(content='Hello again', timestamp=IsNow(tz=timezone.utc)),
+                LLMToolCalls(
+                    calls=[ToolCall(tool_name='ret_a', args=ArgsObject(args_object={'x': 'a'}))],
+                    timestamp=IsNow(tz=timezone.utc),
+                ),
+                ToolReturn(tool_name='ret_a', content='a-apple', timestamp=IsNow(tz=timezone.utc)),
+                LLMResponse(content='{"ret_a":"a-apple"}', timestamp=IsNow(tz=timezone.utc)),
             ],
-            new_message_index=1,
+            _new_message_index=5,
             cost=Cost(),
         )
     )
+    new_msg_roles = [msg.role for msg in result2.new_messages()]
+    assert new_msg_roles == snapshot(['user', 'llm-tool-calls', 'tool-return', 'llm-response'])
+    assert result2.new_messages_json().startswith(b'[{"content":"Hello again",')
 
-    result = agent.run_sync('Hello again', message_history=result.all_messages)
-    assert result == snapshot(
+    # if we pass all_messages, system prompt is NOT inserted before the message_history messages,
+    # so only one system prompt
+    result3 = agent.run_sync('Hello again', message_history=result1.all_messages())
+    # same as result2 except for datetimes
+    assert result3 == snapshot(
         RunResult(
             response='{"ret_a":"a-apple"}',
-            all_messages=[
+            _all_messages=[
                 SystemPrompt(content='Foobar'),
                 UserPrompt(content='Hello', timestamp=IsNow(tz=timezone.utc)),
                 LLMToolCalls(
@@ -405,10 +433,7 @@ async def ret_a(x: str) -> str:
                 ToolReturn(tool_name='ret_a', content='a-apple', timestamp=IsNow(tz=timezone.utc)),
                 LLMResponse(content='{"ret_a":"a-apple"}', timestamp=IsNow(tz=timezone.utc)),
             ],
-            new_message_index=5,
+            _new_message_index=5,
             cost=Cost(),
         )
     )
-    new_msg_roles = [msg.role for msg in result.new_messages()]
-    assert new_msg_roles == snapshot(['user', 'llm-tool-calls', 'tool-return', 'llm-response'])
-    assert result.new_messages_json().startswith(b'[{"content":"Hello again",')