# Copyright (c) Microsoft. All rights reserved. import asyncio import re from collections.abc import AsyncIterable, Awaitable, Callable from random import randint from typing import Annotated from agent_framework import ( AgentContext, AgentResponse, AgentResponseUpdate, ChatContext, ChatResponse, ChatResponseUpdate, Content, Message, ResponseStream, tool, ) from agent_framework.openai import OpenAIResponsesClient from dotenv import load_dotenv from pydantic import Field # Load environment variables from .env file load_dotenv() """ Result Override with MiddlewareTypes (Regular and Streaming) This sample demonstrates how to use middleware to intercept and modify function results after execution, supporting both regular and streaming agent responses. The example shows: - How to execute the original function first and then modify its result - Replacing function outputs with custom messages or transformed data - Using middleware for result filtering, formatting, or enhancement - Detecting streaming vs non-streaming execution using context.stream - Overriding streaming results with custom async generators The weather override middleware lets the original weather function execute normally, then replaces its result with a custom "perfect weather" message. For streaming responses, it creates a custom async generator that yields the override message in chunks. """ # NOTE: approval_mode="never_require" is for sample brevity. Use "always_require" in production; # see samples/02-agents/tools/function_tool_with_approval.py # and samples/02-agents/tools/function_tool_with_approval_and_sessions.py. @tool(approval_mode="never_require") def get_weather( location: Annotated[str, Field(description="The location to get the weather for.")], ) -> str: """Get the weather for a given location.""" conditions = ["sunny", "cloudy", "rainy", "stormy"] return f"The weather in {location} is {conditions[randint(0, 3)]} with a high of {randint(10, 30)}°C." async def weather_override_middleware(context: ChatContext, call_next: Callable[[], Awaitable[None]]) -> None: """Chat middleware that overrides weather results for both streaming and non-streaming cases.""" # Let the original agent execution complete first await call_next() # Check if there's a result to override (agent called weather function) if context.result is not None: # Create custom weather message chunks = [ "due to special atmospheric conditions, ", "all locations are experiencing perfect weather today! ", "Temperature is a comfortable 22°C with gentle breezes. ", "Perfect day for outdoor activities!", ] if context.stream and isinstance(context.result, ResponseStream): async def _override_stream() -> AsyncIterable[ChatResponseUpdate]: for i, chunk_text in enumerate(chunks): yield ChatResponseUpdate( contents=[Content.from_text(text=f"Weather Advisory: [{i}] {chunk_text}")], role="assistant", ) context.result = ResponseStream(_override_stream()) else: # For non-streaming: just replace with a new message current_text = context.result.text if isinstance(context.result, ChatResponse) else "" custom_message = f"Weather Advisory: [0] {''.join(chunks)} Original message was: {current_text}" context.result = ChatResponse(messages=[Message(role="assistant", text=custom_message)]) async def validate_weather_middleware(context: ChatContext, call_next: Callable[[], Awaitable[None]]) -> None: """Chat middleware that simulates result validation for both streaming and non-streaming cases.""" await call_next() validation_note = "Validation: weather data verified." if context.result is None: return if context.stream and isinstance(context.result, ResponseStream): def _append_validation_note(response: ChatResponse) -> ChatResponse: response.messages.append(Message(role="assistant", text=validation_note)) return response context.result.with_finalizer(_append_validation_note) elif isinstance(context.result, ChatResponse): context.result.messages.append(Message(role="assistant", text=validation_note)) async def agent_cleanup_middleware(context: AgentContext, call_next: Callable[[], Awaitable[None]]) -> None: """Agent middleware that validates chat middleware effects and cleans the result.""" await call_next() if context.result is None: return validation_note = "Validation: weather data verified." state = {"found_prefix": False} def _sanitize(response: AgentResponse) -> AgentResponse: found_prefix = state["found_prefix"] found_validation = False cleaned_messages: list[Message] = [] for message in response.messages: text = message.text if text is None: cleaned_messages.append(message) continue if validation_note in text: found_validation = True text = text.replace(validation_note, "").strip() if not text: continue if "Weather Advisory:" in text: found_prefix = True text = text.replace("Weather Advisory:", "") text = re.sub(r"\[\d+\]\s*", "", text) cleaned_messages.append( Message( role=message.role, text=text.strip(), author_name=message.author_name, message_id=message.message_id, additional_properties=message.additional_properties, raw_representation=message.raw_representation, ) ) if not found_prefix: raise RuntimeError("Expected chat middleware prefix not found in agent response.") if not found_validation: raise RuntimeError("Expected validation note not found in agent response.") cleaned_messages.append(Message(role="assistant", text=" Agent: OK")) response.messages = cleaned_messages return response if context.stream and isinstance(context.result, ResponseStream): def _clean_update(update: AgentResponseUpdate) -> AgentResponseUpdate: for content in update.contents or []: if not content.text: continue text = content.text if "Weather Advisory:" in text: state["found_prefix"] = True text = text.replace("Weather Advisory:", "") text = re.sub(r"\[\d+\]\s*", "", text) content.text = text return update context.result.with_transform_hook(_clean_update) context.result.with_finalizer(_sanitize) elif isinstance(context.result, AgentResponse): context.result = _sanitize(context.result) async def main() -> None: """Example demonstrating result override with middleware for both streaming and non-streaming.""" print("=== Result Override MiddlewareTypes Example ===") # For authentication, run `az login` command in terminal or replace AzureCliCredential with preferred # authentication option. agent = OpenAIResponsesClient( middleware=[validate_weather_middleware, weather_override_middleware], ).as_agent( name="WeatherAgent", instructions="You are a helpful weather assistant. Use the weather tool to get current conditions.", tools=get_weather, middleware=[agent_cleanup_middleware], ) # Non-streaming example print("\n--- Non-streaming Example ---") query = "What's the weather like in Seattle?" print(f"User: {query}") result = await agent.run(query) print(f"Agent: {result}") # Streaming example print("\n--- Streaming Example ---") query = "What's the weather like in Portland?" print(f"User: {query}") print("Agent: ", end="", flush=True) response = agent.run(query, stream=True) async for chunk in response: if chunk.text: print(chunk.text, end="", flush=True) print("\n") print(f"Final Result: {(await response.get_final_response()).text}") if __name__ == "__main__": asyncio.run(main())