feat(ag2): add AG2 reviewer sample and demo UI (clean)

samples/python/agents/ag2/README.md

@@ -38,54 +38,35 @@ sequenceDiagram
 
 ## The demo
 
-Here we have a simple demo that shows how to use the A2A protocol to communicate with an AG2 agent. We have
-- one A2A-served remote agent `a2a_python_reviewer.py`
-- two different A2A clients, which communicate with the remote agent using the A2A protocol:
-    CLI code generator `cli_codegen_a2a_client.py` and FastAPI code generator `fastapi_codegen_a2a_client.py`
+This demo shows how to use the A2A protocol to communicate with an AG2 agent using a simple server/client architecture.
 
-## Prerequisites
-
-- Python 3.12 or higher
-- UV package manager
-- OpenAI API Key (for default configuration)
-
-## Setup & Running
-
-1. Navigate to the samples directory:
-
-    ```bash
-    cd samples/python/agents/ag2
-    ```
+4. Run the remote agent:
 
-2. Create an environment file with your API key (uses `openai gpt-4o`):
+```bash
+uv run a2a_python_reviewer.py
+```
 
-    ```bash
-    echo "OPENAI_API_KEY=your_api_key_here" > .env
-    ```
+5. In a new terminal, start an A2A client to interact with the remote `ReviewerAgent`. Choose one of the following:
 
-3. Install the dependencies:
-    ```bash
-    uv sync
-    ```
+- CLI client (generates CLI scripts):
 
-4. Run the remote agent:
-    ```bash
-    uv run a2a_python_reviewer.py
-    ```
+```bash
+uv run cli_codegen_a2a_client.py
+```
 
-5. In a new terminal, start an A2AClient interface to interact with the remote (ag2) agent. You can use one of the following clients:
+- FastAPI client (generates FastAPI apps):
 
-    - **Method A: Run the CLI client**
+```bash
+uv run fastapi_codegen_a2a_client.py
+```
 
-        ```bash
-        uv run cli_codegen_a2a_client.py
-        ```
+- Optional: WebSocket demo UI (visual demo only):
 
-    - **Method B: Run the FastAPI client**
+```bash
+uv run websocket.py
+```
 
-        ```bash
-        uv run fastapi_codegen_a2a_client.py
-        ```
+Then open [http://127.0.0.1:9000](http://127.0.0.1:9000) in your browser for the pixel-art themed interactive demo.
 
 ## Learn More
 

samples/python/agents/ag2/a2a_python_reviewer.py

@@ -3,6 +3,14 @@
 
 from typing import Annotated
 
+# Load .env file if python-dotenv is available
+try:
+    from dotenv import load_dotenv
+
+    load_dotenv()
+except ImportError:
+    pass
+
 from autogen import ConversableAgent, LLMConfig
 from autogen.a2a import A2aAgentServer
 from mypy import api
@@ -11,48 +19,60 @@
 # create regular AG2 agent
 config = LLMConfig(
     {
-        'model': 'gpt-4o-mini',
-        'api_key': os.getenv('OPENAI_API_KEY'),
+        "model": "gpt-4o-mini",
+        "api_key": os.getenv("OPENAI_API_KEY"),
     }
 )
 
 reviewer_agent = ConversableAgent(
-    name='ReviewerAgent',
-    description='An agent that reviews the code for the user',
+    name="ReviewerAgent",
+    description="An agent that reviews the code for the user",
     system_message=(
-        'You are an expert in code review pretty strict and focused on typing. '
-        'Please, use mypy tool to validate the code.'
-        'If mypy has no issues with the code, return "No issues found."'
+        "You are an expert in code review: strict and focused on typing. "
+        "Please use the mypy tool to validate the code. "
+        "If mypy has no issues with the code, return exactly: No issues found."
     ),
     llm_config=config,
-    human_input_mode='NEVER',
+    human_input_mode="NEVER",
 )
 
 
 # Add mypy tool to validate the code
 @reviewer_agent.register_for_llm(
-    name='mypy-checker',
-    description='Check the code with mypy tool',
+    name="mypy-checker",
+    description="Check the code with mypy tool",
 )
 def review_code_with_mypy(
     code: Annotated[
         str,
-        'Raw code content to review. Code should be formatted as single file.',
+        "Raw code content to review. Code should be formatted as single file.",
     ],
 ) -> str:
-    with tempfile.NamedTemporaryFile('w', suffix='.py') as tmp:
+    # Windows-safe: create a temp file, close it, run mypy, then remove the file.
+    with tempfile.NamedTemporaryFile("w", suffix=".py", delete=False) as tmp:
         tmp.write(code)
-        stdout, stderr, exit_status = api.run([tmp.name])
-    if exit_status != 0:
-        return stderr
-    return stdout or 'No issues found.'
+        tmp_path = tmp.name
+    try:
+        stdout, stderr, exit_status = api.run([tmp_path, "--ignore-missing-imports"])
+    finally:
+        try:
+            os.unlink(tmp_path)
+        except OSError:
+            pass
+
+    # When mypy exits with 0, return the exact agreed success token.
+    if exit_status == 0:
+        return "No issues found."
+
+    # Otherwise return any output we got (stdout preferred, then stderr).
+    return (stdout or stderr) or "mypy reported issues."
 
 
 # wrap agent to A2A server
 server = A2aAgentServer(reviewer_agent).build()
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     # run server as regular ASGI application
     import uvicorn
 
-    uvicorn.run(server, host='0.0.0.0', port=8000)
+    uvicorn.run(server, host="0.0.0.0", port=8000)

samples/python/agents/ag2/demo/README.md

@@ -0,0 +1,42 @@
+# AG2 Demo UI
+
+This folder contains the browser-based WebSocket demo interface for the AG2 A2A sample.
+
+## Files
+
+- **`ui.html`** - Main HTML/CSS/JavaScript for the pixel-art themed demo UI
+- **`assets/`** - Visual assets for the interface
+
+## Assets
+
+- `banner.png` - Top title banner (AG2 × A2A)
+- `background-clouds.png` - Sky background
+- `code-box.png` - Stone frame for code/log panels
+- `grass-bottom.png` - Grass strip at the bottom
+
+## How it works
+
+1. The parent folder's `websocket.py` serves this UI at `http://127.0.0.1:9000/`
+2. The browser connects via WebSocket to interact with the AG2 agents
+3. The UI displays:
+   - **Prompt box** - Enter code generation requests
+   - **Live Backend Logs** - Real-time status updates and agent conversations
+   - **Generated Code** - Final code output after review iterations
+
+## Running the demo
+
+From the parent directory:
+
+```bash
+uv run websocket.py
+```
+
+Then open `http://127.0.0.1:9000/` in your browser.
+
+## Design notes
+
+The UI uses a retro pixel-art aesthetic inspired by classic RPG games:
+- 16-bit style graphics
+- Stone-framed panels for content
+- Pixel-rendered fonts
+- Sky background with grass footer