Fix new_messages() when deferred_tool_results is used with message_history ending in ToolReturnParts (#2913)

DouweM · web-flow · commit ccd5e6ab770a · 2025-09-15T23:33:27.000Z
diff --git a/docs/agents.md b/docs/agents.md
@@ -280,7 +280,6 @@ async def main():
     [
         UserPromptNode(
             user_prompt='What is the capital of France?',
-            instructions=None,
             instructions_functions=[],
             system_prompts=(),
             system_prompt_functions=[],
@@ -343,7 +342,6 @@ async def main():
         [
             UserPromptNode(
                 user_prompt='What is the capital of France?',
-                instructions=None,
                 instructions_functions=[],
                 system_prompts=(),
                 system_prompt_functions=[],
diff --git a/docs/deferred-tools.md b/docs/deferred-tools.md
@@ -132,17 +132,21 @@ print(result.all_messages())
     ),
     ModelRequest(
         parts=[
-            ToolReturnPart(
-                tool_name='delete_file',
-                content='Deleting files is not allowed',
-                tool_call_id='delete_file',
-                timestamp=datetime.datetime(...),
-            ),
             ToolReturnPart(
                 tool_name='update_file',
                 content="File 'README.md' updated: 'Hello, world!'",
                 tool_call_id='update_file_readme',
                 timestamp=datetime.datetime(...),
+            )
+        ]
+    ),
+    ModelRequest(
+        parts=[
+            ToolReturnPart(
+                tool_name='delete_file',
+                content='Deleting files is not allowed',
+                tool_call_id='delete_file',
+                timestamp=datetime.datetime(...),
             ),
             ToolReturnPart(
                 tool_name='update_file',
diff --git a/pydantic_ai_slim/pydantic_ai/_agent_graph.py b/pydantic_ai_slim/pydantic_ai/_agent_graph.py
diff --git a/pydantic_ai_slim/pydantic_ai/agent/__init__.py b/pydantic_ai_slim/pydantic_ai/agent/__init__.py
@@ -45,15 +45,11 @@
 from ..settings import ModelSettings, merge_model_settings
 from ..tools import (
     AgentDepsT,
-    DeferredToolCallResult,
-    DeferredToolResult,
     DeferredToolResults,
     DocstringFormat,
     GenerateToolJsonSchema,
     RunContext,
     Tool,
-    ToolApproved,
-    ToolDenied,
     ToolFuncContext,
     ToolFuncEither,
     ToolFuncPlain,
@@ -462,7 +458,7 @@ def iter(
     ) -> AbstractAsyncContextManager[AgentRun[AgentDepsT, RunOutputDataT]]: ...
 
     @asynccontextmanager
-    async def iter(  # noqa: C901
+    async def iter(
         self,
         user_prompt: str | Sequence[_messages.UserContent] | None = None,
         *,
@@ -505,7 +501,6 @@ async def main():
             [
                 UserPromptNode(
                     user_prompt='What is the capital of France?',
-                    instructions=None,
                     instructions_functions=[],
                     system_prompts=(),
                     system_prompt_functions=[],
@@ -559,7 +554,6 @@ async def main():
         del model
 
         deps = self._get_deps(deps)
-        new_message_index = len(message_history) if message_history else 0
         output_schema = self._prepare_output_schema(output_type, model_used.profile)
 
         output_type_ = output_type or self.output_type
@@ -620,27 +614,12 @@ async def get_instructions(run_context: RunContext[AgentDepsT]) -> str | None:
             instrumentation_settings = None
             tracer = NoOpTracer()
 
-        tool_call_results: dict[str, DeferredToolResult] | None = None
-        if deferred_tool_results is not None:
-            tool_call_results = {}
-            for tool_call_id, approval in deferred_tool_results.approvals.items():
-                if approval is True:
-                    approval = ToolApproved()
-                elif approval is False:
-                    approval = ToolDenied()
-                tool_call_results[tool_call_id] = approval
-
-            if calls := deferred_tool_results.calls:
-                call_result_types = _utils.get_union_args(DeferredToolCallResult)
-                for tool_call_id, result in calls.items():
-                    if not isinstance(result, call_result_types):
-                        result = _messages.ToolReturn(result)
-                    tool_call_results[tool_call_id] = result
-
-        graph_deps = _agent_graph.GraphAgentDeps[AgentDepsT, RunOutputDataT](
+        graph_deps = _agent_graph.GraphAgentDeps[
+            AgentDepsT, RunOutputDataT
+        ](
             user_deps=deps,
             prompt=user_prompt,
-            new_message_index=new_message_index,
+            new_message_index=0,  # This will be set in `UserPromptNode` based on the length of the cleaned message history
             model=model_used,
             model_settings=model_settings,
             usage_limits=usage_limits,
@@ -651,13 +630,13 @@ async def get_instructions(run_context: RunContext[AgentDepsT]) -> str | None:
             history_processors=self.history_processors,
             builtin_tools=list(self._builtin_tools),
             tool_manager=tool_manager,
-            tool_call_results=tool_call_results,
             tracer=tracer,
             get_instructions=get_instructions,
             instrumentation_settings=instrumentation_settings,
         )
         start_node = _agent_graph.UserPromptNode[AgentDepsT](
             user_prompt=user_prompt,
+            deferred_tool_results=deferred_tool_results,
             instructions=self._instructions,
             instructions_functions=self._instructions_functions,
             system_prompts=self._system_prompts,
diff --git a/pydantic_ai_slim/pydantic_ai/agent/abstract.py b/pydantic_ai_slim/pydantic_ai/agent/abstract.py
@@ -499,12 +499,13 @@ async def on_complete() -> None:
                                 ]
 
                                 parts: list[_messages.ModelRequestPart] = []
-                                async for _event in _agent_graph.process_function_tools(
-                                    graph_ctx.deps.tool_manager,
-                                    tool_calls,
-                                    final_result,
-                                    graph_ctx,
-                                    parts,
+                                async for _event in _agent_graph.process_tool_calls(
+                                    tool_manager=graph_ctx.deps.tool_manager,
+                                    tool_calls=tool_calls,
+                                    tool_call_results=None,
+                                    final_result=final_result,
+                                    ctx=graph_ctx,
+                                    output_parts=parts,
                                 ):
                                     pass
                                 if parts:
@@ -621,7 +622,6 @@ async def main():
             [
                 UserPromptNode(
                     user_prompt='What is the capital of France?',
-                    instructions=None,
                     instructions_functions=[],
                     system_prompts=(),
                     system_prompt_functions=[],
diff --git a/pydantic_ai_slim/pydantic_ai/agent/wrapper.py b/pydantic_ai_slim/pydantic_ai/agent/wrapper.py
@@ -144,7 +144,6 @@ async def main():
             [
                 UserPromptNode(
                     user_prompt='What is the capital of France?',
-                    instructions=None,
                     instructions_functions=[],
                     system_prompts=(),
                     system_prompt_functions=[],
diff --git a/pydantic_ai_slim/pydantic_ai/durable_exec/dbos/_agent.py b/pydantic_ai_slim/pydantic_ai/durable_exec/dbos/_agent.py
@@ -627,7 +627,6 @@ async def main():
             [
                 UserPromptNode(
                     user_prompt='What is the capital of France?',
-                    instructions=None,
                     instructions_functions=[],
                     system_prompts=(),
                     system_prompt_functions=[],
diff --git a/pydantic_ai_slim/pydantic_ai/durable_exec/temporal/_agent.py b/pydantic_ai_slim/pydantic_ai/durable_exec/temporal/_agent.py
@@ -660,7 +660,6 @@ async def main():
             [
                 UserPromptNode(
                     user_prompt='What is the capital of France?',
-                    instructions=None,
                     instructions_functions=[],
                     system_prompts=(),
                     system_prompt_functions=[],
diff --git a/pydantic_ai_slim/pydantic_ai/run.py b/pydantic_ai_slim/pydantic_ai/run.py
@@ -48,7 +48,6 @@ async def main():
         [
             UserPromptNode(
                 user_prompt='What is the capital of France?',
-                instructions=None,
                 instructions_functions=[],
                 system_prompts=(),
                 system_prompt_functions=[],
@@ -183,7 +182,6 @@ async def main():
                 [
                     UserPromptNode(
                         user_prompt='What is the capital of France?',
-                        instructions=None,
                         instructions_functions=[],
                         system_prompts=(),
                         system_prompt_functions=[],
diff --git a/tests/test_a2a.py b/tests/test_a2a.py
@@ -623,10 +623,10 @@ def track_messages(messages: list[ModelMessage], info: AgentInfo) -> ModelRespon
                                 content='Final result processed.',
                                 tool_call_id=IsStr(),
                                 timestamp=IsDatetime(),
-                            )
-                        ]
+                            ),
+                            UserPromptPart(content='Second message', timestamp=IsDatetime()),
+                        ],
                     ),
-                    ModelRequest(parts=[UserPromptPart(content='Second message', timestamp=IsDatetime())]),
                 ]
             )
 
diff --git a/tests/test_agent.py b/tests/test_agent.py
diff --git a/tests/test_history_processor.py b/tests/test_history_processor.py
diff --git a/tests/test_tools.py b/tests/test_tools.py

Original file line number	Diff line number	Diff line change
`@@ -144,7 +144,6 @@ async def main():`
`144`	`144`	`[`
`145`	`145`	`UserPromptNode(`
`146`	`146`	`user_prompt='What is the capital of France?',`
`147`		`- instructions=None,`
`148`	`147`	`instructions_functions=[],`
`149`	`148`	`system_prompts=(),`
`150`	`149`	`system_prompt_functions=[],`
Original file line number	Diff line number	Diff line change
`@@ -627,7 +627,6 @@ async def main():`
`627`	`627`	`[`
`628`	`628`	`UserPromptNode(`
`629`	`629`	`user_prompt='What is the capital of France?',`
`630`		`- instructions=None,`
`631`	`630`	`instructions_functions=[],`
`632`	`631`	`system_prompts=(),`
`633`	`632`	`system_prompt_functions=[],`
Original file line number	Diff line number	Diff line change
`@@ -660,7 +660,6 @@ async def main():`
`660`	`660`	`[`
`661`	`661`	`UserPromptNode(`
`662`	`662`	`user_prompt='What is the capital of France?',`
`663`		`- instructions=None,`
`664`	`663`	`instructions_functions=[],`
`665`	`664`	`system_prompts=(),`
`666`	`665`	`system_prompt_functions=[],`
Original file line number	Diff line number	Diff line change
`@@ -623,10 +623,10 @@ def track_messages(messages: list[ModelMessage], info: AgentInfo) -> ModelRespon`
`623`	`623`	`content='Final result processed.',`
`624`	`624`	`tool_call_id=IsStr(),`
`625`	`625`	`timestamp=IsDatetime(),`
`626`		`- )`
`627`		`- ]`
	`626`	`+ ),`
	`627`	`+ UserPromptPart(content='Second message', timestamp=IsDatetime()),`
	`628`	`+ ],`
`628`	`629`	`),`
`629`		`- ModelRequest(parts=[UserPromptPart(content='Second message', timestamp=IsDatetime())]),`
`630`	`630`	`]`
`631`	`631`	`)`
`632`	`632`