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agent-framework/python/packages/core/AGENTS.md
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Eduard van Valkenburg 0521f5bed8 Python: [BREAKING] Simplify API: ChatAgent -> Agent, ChatMessage -> Message (#3747)
* [BREAKING] Rename ChatAgent -> Agent, ChatMessage -> Message, ChatClientProtocol -> SupportsChatGetResponse

Simplify the public API by removing redundant 'Chat' prefix from core types:
- ChatAgent -> Agent
- RawChatAgent -> RawAgent
- ChatMessage -> Message
- ChatClientProtocol -> SupportsChatGetResponse

Also renamed internal WorkflowMessage (was Message in _runner_context) to avoid collision.

No backward compatibility aliases - this is a clean breaking change.

* [BREAKING] Rename Agent chat_client parameter to client

* Fix rebase issues: WorkflowMessage references and broken markdown links

* Fix formatting and lint issues from code quality checks

* Fix import ordering in workflow sample files

* fixed rebase

* Fix test failures: use WorkflowMessage and A2AMessage after ChatMessage→Message rename

- Replace Message(data=..., source_id=...) with WorkflowMessage(...) in workflow tests
- Fix isinstance check in A2A agent to use A2AMessage instead of Message
- Fix import in test_workflow_observability.py (Message→WorkflowMessage)

* Fix lint, fmt, and sample errors after ChatMessage→Message rename

- Auto-fix 70+ ruff lint issues across samples (ChatMessage→Message refs)
- Fix HostedVectorStoreContent→Content.from_hosted_vector_store in file search sample
- Fix _normalize_messages→normalize_messages in custom agent sample
- Fix context.terminate→raise MiddlewareTermination in middleware samples
- Fix with_update_hook→with_transform_hook in override middleware sample
- Add TOptions_co import back to custom_chat_client sample
- Add noqa for FastAPI File() default in chatkit sample
- Fix B023 loop variable capture in weather agent sample

* fix: update Agent constructor calls from chat_client to client in declaration-only tool tests

* fix: add register_cleanup to devui lazy-loading proxy and type stub

* fixed tests and updated new pieces

* fix agui typevar

* fix merge errors

* fix merge conflicts

* fiux merge

* Remove unused links

---------

Co-authored-by: Evan Mattson <evan.mattson@microsoft.com>
2026-02-10 23:04:32 +00:00

5.0 KiB

Core Package (agent-framework-core)

The foundation package containing all core abstractions, types, and built-in OpenAI/Azure OpenAI support.

Module Structure

agent_framework/
├── __init__.py          # Public API exports
├── _agents.py           # Agent implementations
├── _clients.py          # Chat client base classes and protocols
├── _types.py            # Core types (Message, ChatResponse, Content, etc.)
├── _tools.py            # Tool definitions and function invocation
├── _middleware.py       # Middleware system for request/response interception
├── _threads.py          # AgentThread and message store abstractions
├── _memory.py           # Context providers for memory/RAG
├── _mcp.py              # Model Context Protocol support
├── _workflows/          # Workflow orchestration (sequential, concurrent, handoff, etc.)
├── openai/              # Built-in OpenAI client
├── azure/               # Lazy-loading entry point for Azure integrations
└── <provider>/          # Other lazy-loading provider folders

Core Classes

Agents (_agents.py)

  • SupportsAgentRun - Protocol defining the agent interface
  • BaseAgent - Abstract base class for agents
  • Agent - Main agent class wrapping a chat client with tools, instructions, and middleware

Chat Clients (_clients.py)

  • SupportsChatGetResponse - Protocol for chat client implementations
  • BaseChatClient - Abstract base class with middleware support; subclasses implement _inner_get_response() and _inner_get_streaming_response()

Types (_types.py)

  • Message - Represents a chat message with role, content, and metadata
  • ChatResponse - Response from a chat client containing messages and usage
  • ChatResponseUpdate - Streaming response update
  • AgentResponse / AgentResponseUpdate - Agent-level response wrappers
  • Content - Base class for message content (text, function calls, images, etc.)
  • ChatOptions - TypedDict for chat request options

Tools (_tools.py)

  • ToolProtocol - Protocol for tool definitions
  • FunctionTool - Wraps Python functions as tools with JSON schema generation
  • @tool decorator - Converts functions to tools
  • use_function_invocation() - Decorator to add automatic function calling to chat clients

Middleware (_middleware.py)

  • AgentMiddleware - Intercepts agent run() calls
  • ChatMiddleware - Intercepts chat client get_response() calls
  • FunctionMiddleware - Intercepts function/tool invocations
  • AgentContext / ChatContext / FunctionInvocationContext - Context objects passed through middleware

Threads (_threads.py)

  • AgentThread - Manages conversation history for an agent
  • ChatMessageStoreProtocol - Protocol for persistent message storage
  • ChatMessageStore - Default in-memory implementation

Memory (_memory.py)

  • ContextProvider - Protocol for providing additional context to agents (RAG, memory systems)
  • Context - Container for context data

Workflows (_workflows/)

  • Workflow - Graph-based workflow definition
  • WorkflowBuilder - Fluent API for building workflows
  • Orchestrators: SequentialOrchestrator, ConcurrentOrchestrator, GroupChatOrchestrator, MagenticOrchestrator, HandoffOrchestrator

Built-in Providers

OpenAI (openai/)

  • OpenAIChatClient - Chat client for OpenAI API
  • OpenAIResponsesClient - Client for OpenAI Responses API

Azure OpenAI (azure/)

  • AzureOpenAIChatClient - Chat client for Azure OpenAI
  • AzureOpenAIResponsesClient - Client for Azure OpenAI Responses API

Key Patterns

Creating an Agent

from agent_framework import Agent
from agent_framework.openai import OpenAIChatClient

agent = Agent(
    client=OpenAIChatClient(),
    instructions="You are helpful.",
    tools=[my_function],
)
response = await agent.run("Hello")

Using as_agent() Shorthand

agent = OpenAIChatClient().as_agent(
    name="Assistant",
    instructions="You are helpful.",
)

Middleware Pipeline

from agent_framework import Agent, AgentMiddleware, AgentContext

class LoggingMiddleware(AgentMiddleware):
    async def process(self, context: AgentContext, call_next) -> None:
        print(f"Input: {context.messages}")
        await call_next(context)
        print(f"Output: {context.result}")

agent = Agent(..., middleware=[LoggingMiddleware()])

Custom Chat Client

from agent_framework import BaseChatClient, ChatResponse, Message

class MyClient(BaseChatClient):
    async def _inner_get_response(self, *, messages, options, **kwargs) -> ChatResponse:
        # Call your LLM here
        return ChatResponse(messages=[Message(role="assistant", text="Hi!")])

    async def _inner_get_streaming_response(self, *, messages, options, **kwargs):
        yield ChatResponseUpdate(...)