Message history

app/backend/main.py

@@ -6,6 +6,13 @@ from agent import ChatDeps, ChatSessionState, create_chat_agent
 from anyio import create_memory_object_stream, create_task_group
 from anyio.streams.memory import MemoryObjectSendStream
 from dotenv import load_dotenv
+from pydantic_ai.messages import (
+    ModelMessage,
+    ModelRequest,
+    ModelResponse,
+    TextPart,
+    UserPromptPart,
+)
 from starlette.applications import Starlette
 from starlette.middleware import Middleware
 from starlette.middleware.cors import CORSMiddleware
@@ -19,6 +26,30 @@ from haiku.rag.config.models import AppConfig
 from haiku.rag.graph.agui.emitter import AGUIEmitter
 from haiku.rag.graph.agui.server import RunAgentInput, format_sse_event
 
+
+def convert_messages_to_history(
+    messages: list[dict[str, str]],
+) -> list[ModelMessage]:
+    """Convert AG-UI/CopilotKit messages to pydantic-ai message history.
+
+    Skips the last message since it will be passed as user_prompt to agent.run().
+    """
+    history: list[ModelMessage] = []
+
+    # Skip the last message - it will be the current user prompt
+    for msg in messages[:-1]:
+        role = msg.get("role", "")
+        content = msg.get("content", "")
+
+        if role == "user":
+            history.append(ModelRequest(parts=[UserPromptPart(content=content)]))
+        elif role == "assistant":
+            history.append(ModelResponse(parts=[TextPart(content=content)]))
+        # Skip other roles (system, tool, etc.) for now
+
+    return history
+
+
 load_dotenv()
 
 logging.basicConfig(
@@ -65,8 +96,10 @@ async def stream_chat(request: Request) -> StreamingResponse:
     input_data = RunAgentInput(**body)
 
     user_message = ""
+    message_history: list[ModelMessage] = []
     if input_data.messages:
         user_message = input_data.messages[-1].get("content", "")
+        message_history = convert_messages_to_history(input_data.messages)
 
     send_stream, receive_stream = create_memory_object_stream[str]()
 
@@ -113,7 +146,9 @@ async def stream_chat(request: Request) -> StreamingResponse:
                 async with create_task_group() as tg:
                     tg.start_soon(forward_events)
 
-                    result = await chat_agent.run(user_message, deps=deps)
+                    result = await chat_agent.run(
+                        user_message, deps=deps, message_history=message_history
+                    )
                     emitter.log(result.output)
                     emitter.finish_run(result.output)
                     await emitter.close()