CLAUDE.md@public/files/ag-ui/integrations/adk-middleware/python git:20260917.d487f87A

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# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Common Development Commands

**Important**: Use `.venv/bin/pytest` to run tests with the project's virtual environment.

```bash
# Install in editable mode for development
pip install -e .

# Install with dev dependencies
pip install -e ".[dev]"

# Run tests
.venv/bin/pytest

# Run tests with coverage
.venv/bin/pytest --cov=src/ag_ui_adk

# Run a specific test file
.venv/bin/pytest tests/test_adk_agent.py

# Run a specific test
.venv/bin/pytest tests/test_adk_agent.py::test_function_name

# Code formatting
black src tests
isort src tests

# Linting
flake8 src tests

# Type checking
mypy src
```

### Running Examples

```bash
cd examples
uv sync
uv run dev

# Or directly with uvicorn
uvicorn server:app --host 0.0.0.0 --port 8000
```

Requires `GOOGLE_API_KEY` environment variable for Gemini models.

## High-Level Architecture

This package (`ag_ui_adk`) is a middleware that bridges [Google ADK](https://google.github.io/adk-docs/) agents with the [AG-UI Protocol](https://github.com/ag-ui-protocol/ag-ui). It translates between the two frameworks' event systems.

### Core Components (in `src/ag_ui_adk/`)

```
AG-UI Protocol          ADK Middleware           Google ADK
     │                        │                       │
RunAgentInput ──────> ADKAgent.run() ──────> Runner.run_async()
     │                        │                       │
     │                 EventTranslator                │
     │                        │                       │
BaseEvent[] <──────── translate events <──────── Event[]
```

- **`adk_agent.py`** - Main orchestrator `ADKAgent` class that wraps ADK agents for AG-UI compatibility. Manages lifecycle, sessions, and tool coordination.

- **`event_translator.py`** - Converts ADK events to AG-UI protocol events (16 standard event types). Handles streaming text, message boundaries, and per-session isolation.

- **`session_manager.py`** - Singleton managing session lifecycle, cleanup with configurable timeouts, memory service integration, and resource limits.

- **`execution_state.py`** - Tracks background ADK executions, manages asyncio tasks, event queues for streaming, and tool call state.

- **`client_proxy_tool.py`** / **`client_proxy_toolset.py`** - Wraps AG-UI tools for ADK compatibility. All client tools are long-running (fire-and-forget for HITL workflows).

- **`endpoint.py`** - FastAPI integration via `add_adk_fastapi_endpoint()` and `create_adk_app()`.

- **`config.py`** - Configuration classes including `PredictStateMapping` for predictive state updates.

### Key Integration Pattern

```python
from ag_ui_adk import ADKAgent, add_adk_fastapi_endpoint
from google.adk.agents import Agent

# 1. Create ADK agent
my_agent = Agent(name="assistant", instruction="...")

# 2. Wrap with middleware
agent = ADKAgent(adk_agent=my_agent, app_name="my_app", user_id="user123")

# 3. Use directly or add FastAPI endpoint
async for event in agent.run(input_data):
    print(event.type)

# Or with FastAPI
app = FastAPI()
add_adk_fastapi_endpoint(app, agent, path="/chat")
```

### Tool Execution Flow

All client-supplied tools are long-running, ideal for human-in-the-loop workflows:

1. Initial AG-UI Run → ADK Agent starts execution
2. ADK Agent requests tool use → Execution pauses
3. Tool events emitted (TOOL_CALL_START/ARGS/END) → Client receives tool call info
4. Client executes tools → Results prepared asynchronously
5. Subsequent AG-UI Run with ToolMessage → ADK execution resumes
6. Final response → Execution completes

### Environment Variables for Logging

```bash
LOG_ROOT_LEVEL=INFO       # Root logger level
LOG_ADK_AGENT=DEBUG       # adk_agent component
LOG_EVENT_TRANSLATOR=INFO # event_translator component
LOG_ENDPOINT=ERROR        # endpoint component
LOG_SESSION_MANAGER=WARNING # session_manager component
```

## Testing

The test suite has 670+ tests covering:
- Unit tests for each component
- Integration tests for end-to-end flows
- HITL (human-in-the-loop) tool tracking
- Multi-turn conversation handling
- Session management and cleanup
- Concurrent execution limits
- Predictive state updates
- Vertex AI session service (mock + optional live)

Tests use pytest-asyncio for async test support.

### Running All Tests

```bash
# Unit + mock-based integration tests (no credentials needed beyond GOOGLE_API_KEY)
set -a && source .env && set +a
.venv/bin/pytest tests/

# Run a specific test class
.venv/bin/pytest tests/test_vertex_session_service.py::TestVertexSessionServiceMock -v
```

### Vertex AI Session Service Live Tests

The `TestVertexSessionServiceLive` class in `tests/test_vertex_session_service.py`
runs against a real Vertex AI Agent Engine. These tests are **skipped by default**
and only run when `VERTEX_REASONING_ENGINE_ID` is set.

Mock-based tests (10 tests) always run and cover the same middleware code paths
using a `MockVertexAiSessionService` that faithfully replicates Vertex behaviour
(generates numeric IDs, rejects caller-provided `session_id`).

#### Prerequisites

- **GCP Project** with the Vertex AI API enabled
- **Application Default Credentials** (ADC) with Vertex AI permissions
- A **deployed ReasoningEngine** (Agent Engine) — the sessions API requires one

#### 1. Enable the Vertex AI API (if not already)

Via GCP Console: APIs & Services > Library > search "Vertex AI API" > Enable.

Or via gcloud CLI:
```bash
gcloud services enable aiplatform.googleapis.com --project=<PROJECT_ID>
```

#### 2. Deploy a Minimal ReasoningEngine

The engine does not need agent code — it just needs to exist so the sessions
endpoint is available. From the project `.venv`:

```python
import vertexai

client = vertexai.Client(project='<PROJECT_ID>', location='us-central1')
result = client.agent_engines.create(
    config={
        'display_name': 'ag-ui-test-sessions',
        'description': 'Minimal engine for AG-UI middleware session tests',
    }
)
# Extract the engine ID from the resource name
print(result.api_resource.name)
# e.g. projects/123456/locations/us-central1/reasoningEngines/987654321
```

Note the numeric ID at the end of the resource name.

#### 3. Run the Live Tests

```bash
GOOGLE_CLOUD_PROJECT=<PROJECT_ID> \
GOOGLE_CLOUD_LOCATION=us-central1 \
VERTEX_REASONING_ENGINE_ID=<ENGINE_ID> \
.venv/bin/pytest tests/test_vertex_session_service.py -v
```

The live test fixture automatically removes `GOOGLE_API_KEY` and overrides
`GOOGLE_CLOUD_LOCATION` to `us-central1` via `monkeypatch`, since the Vertex
sessions API requires OAuth2/ADC (not API keys) and a real region (not `global`).

#### 4. Cleanup (Important — Avoid Ongoing Charges)

ReasoningEngines incur hosting costs while deployed. Delete after testing:

```python
import vertexai

client = vertexai.Client(project='<PROJECT_ID>', location='us-central1')
engine = client.agent_engines.get(agent_engine_id='<ENGINE_ID>')
engine.delete()
```

Or via REST API (use `?force=true` to delete child sessions left by tests):
```bash
curl -X DELETE \
  -H "Authorization: Bearer $(gcloud auth print-access-token)" \
  "https://us-central1-aiplatform.googleapis.com/v1beta1/projects/<PROJECT_ID>/locations/us-central1/reasoningEngines/<ENGINE_ID>?force=true"
```

Verify deletion:
```bash
curl -H "Authorization: Bearer $(gcloud auth print-access-token)" \
  "https://us-central1-aiplatform.googleapis.com/v1beta1/projects/<PROJECT_ID>/locations/us-central1/reasoningEngines"
```
An empty response (or `{}`) confirms no engines remain.