DevUI - A Sample App for Running Agents and Workflows
A lightweight, standalone sample app interface for running entities (agents/workflows) in the Microsoft Agent Framework supporting directory-based discovery, in-memory entity registration, and sample entity gallery.
[!IMPORTANT]
DevUI is a sample app to help you get started with the Agent Framework. It is not intended for production use. For production, or for features beyond what is provided in this sample app, it is recommended that you build your own custom interface and API server using the Agent Framework SDK.

Quick Start
pip install agent-framework-devui --pre
You can also launch it programmatically
from agent_framework import ChatAgent
from agent_framework.openai import OpenAIChatClient
from agent_framework.devui import serve
def get_weather(location: str) -> str:
"""Get weather for a location."""
return f"Weather in {location}: 72°F and sunny"
agent = ChatAgent(
name="WeatherAgent",
chat_client=OpenAIChatClient(),
tools=[get_weather]
)
serve(entities=[agent], auto_open=True)
In addition, if you have agents/workflows defined in a specific directory structure (see below), you can launch DevUI from the cli to discover and run them.
devui ./agents --port 8080
When DevUI starts with no discovered entities, it displays a sample entity gallery with curated examples from the Agent Framework repository. You can download these samples, review them, and run them locally to get started quickly.
Using MCP Tools
Important: Don't use async with context managers when creating agents with MCP tools for DevUI - connections will close before execution.
mcp_tool = MCPStreamableHTTPTool(url="http://localhost:8011/mcp", chat_client=chat_client)
agent = ChatAgent(tools=mcp_tool)
serve(entities=[agent])
MCP tools use lazy initialization and connect automatically on first use. DevUI attempts to clean up connections on shutdown
Resource Cleanup
Register cleanup hooks to properly close credentials and resources on shutdown:
from azure.identity.aio import DefaultAzureCredential
from agent_framework import ChatAgent
from agent_framework.azure import AzureOpenAIChatClient
from agent_framework_devui import register_cleanup, serve
credential = DefaultAzureCredential()
client = AzureOpenAIChatClient()
agent = ChatAgent(name="MyAgent", chat_client=client)
register_cleanup(agent, credential.close)
serve(entities=[agent])
Works with multiple resources and file-based discovery. See tests for more examples.
Directory Structure
For your agents to be discovered by the DevUI, they must be organized in a directory structure like below. Each agent/workflow must have an __init__.py that exports the required variable (agent or workflow).
Note: .env files are optional but will be automatically loaded if present in the agent/workflow directory or parent entities directory. Use them to store API keys, configuration variables, and other environment-specific settings.
agents/
├── weather_agent/
│ ├── __init__.py # Must export: agent = ChatAgent(...)
│ ├── agent.py
│ └── .env # Optional: API keys, config vars
├── my_workflow/
│ ├── __init__.py # Must export: workflow = WorkflowBuilder()...
│ ├── workflow.py
│ └── .env # Optional: environment variables
└── .env # Optional: shared environment variables
Viewing Telemetry (Otel Traces) in DevUI
Agent Framework emits OpenTelemetry (Otel) traces for various operations. You can view these traces in DevUI by enabling tracing when starting the server.
devui ./agents --tracing framework
OpenAI-Compatible API
For convenience, DevUI provides an OpenAI Responses backend API. This means you can run the backend and also use the OpenAI client sdk to connect to it. Use agent/workflow name as the entity_id in metadata, and set streaming to True as needed.
curl -X POST http://localhost:8080/v1/responses \
-H "Content-Type: application/json" \
-d @- << 'EOF'
{
"metadata": {"entity_id": "weather_agent"},
"input": "Hello world"
}
Or use the OpenAI Python SDK:
from openai import OpenAI
client = OpenAI(
base_url="http://localhost:8080/v1",
api_key="not-needed"
)
response = client.responses.create(
metadata={"entity_id": "weather_agent"},
input="What's the weather in Seattle?"
)
print(response.output[0].content[0].text)
Multi-turn Conversations
Use the standard OpenAI conversation parameter for multi-turn conversations:
conversation = client.conversations.create(
metadata={"agent_id": "weather_agent"}
)
response1 = client.responses.create(
metadata={"entity_id": "weather_agent"},
input="What's the weather in Seattle?",
conversation=conversation.id
)
response2 = client.responses.create(
metadata={"entity_id": "weather_agent"},
input="How about tomorrow?",
conversation=conversation.id
)
How it works: DevUI automatically retrieves the conversation's message history from the stored thread and passes it to the agent. You don't need to manually manage message history - just provide the same conversation ID for follow-up requests.
OpenAI Proxy Mode
DevUI provides an OpenAI Proxy feature for testing OpenAI models directly through the interface without creating custom agents. Enable via Settings → OpenAI Proxy tab.
How it works: The UI sends requests to the DevUI backend (with X-Proxy-Backend: openai header), which then proxies them to OpenAI's Responses API (and Conversations API for multi-turn chats). This proxy approach keeps your OPENAI_API_KEY secure on the server—never exposed in the browser or client-side code.
Example:
curl -X POST http://localhost:8080/v1/responses \
-H "X-Proxy-Backend: openai" \
-d '{"model": "gpt-4.1-mini", "input": "Hello"}'
Note: Requires OPENAI_API_KEY environment variable configured on the backend.
CLI Options
devui [directory] [options]
Options:
--port, -p Port (default: 8080)
--host Host (default: 127.0.0.1)
--headless API only, no UI
--config YAML config file
--tracing none|framework|workflow|all
--reload Enable auto-reload
--mode developer|user (default: developer)
--auth Enable Bearer token authentication
UI Modes
- developer (default): Full access - debug panel, entity details, hot reload, deployment
- user: Simplified UI with restricted APIs - only chat and conversation management
devui ./agents
devui ./agents --mode user --auth
Key Endpoints
API Mapping
Given that DevUI offers an OpenAI Responses API, it internally maps messages and events from Agent Framework to OpenAI Responses API events (in _mapper.py). For transparency, this mapping is shown below:
| Lifecycle Events | |
response.created + response.in_progress | AgentStartedEvent | OpenAI |
response.completed | AgentCompletedEvent | OpenAI |
response.failed | AgentFailedEvent | OpenAI |
response.created + response.in_progress | WorkflowStartedEvent | OpenAI |
response.completed | WorkflowCompletedEvent | OpenAI |
response.failed | WorkflowFailedEvent | OpenAI |
| Content Types | |
response.content_part.added + response.output_text.delta | TextContent | OpenAI |
response.reasoning_text.delta | TextReasoningContent | OpenAI |
response.output_item.added | FunctionCallContent (initial) | OpenAI |
response.function_call_arguments.delta | FunctionCallContent (args) | OpenAI |
response.function_result.complete | FunctionResultContent | DevUI |
response.function_approval.requested | FunctionApprovalRequestContent | DevUI |
response.function_approval.responded | FunctionApprovalResponseContent | DevUI |
response.output_item.added (ResponseOutputImage) | DataContent (images) | DevUI |
response.output_item.added (ResponseOutputFile) | DataContent (files) | DevUI |
response.output_item.added (ResponseOutputData) | DataContent (other) | DevUI |
response.output_item.added (ResponseOutputImage/File) | UriContent (images/files) | DevUI |
error | ErrorContent | OpenAI |
Final Response.usage field (not streamed) | UsageContent | OpenAI |
| Workflow Events | |
response.output_item.added (ExecutorActionItem)* | ExecutorInvokedEvent | OpenAI |
response.output_item.done (ExecutorActionItem)* | ExecutorCompletedEvent | OpenAI |
response.output_item.done (ExecutorActionItem with error)* | ExecutorFailedEvent | OpenAI |
response.output_item.added (ResponseOutputMessage) | WorkflowOutputEvent | OpenAI |
response.workflow_event.complete | WorkflowEvent (other) | DevUI |
response.trace.complete | WorkflowStatusEvent | DevUI |
response.trace.complete | WorkflowWarningEvent | DevUI |
| Trace Content | |
response.trace.complete | DataContent (no data/errors) | DevUI |
response.trace.complete | UriContent (unsupported MIME) | DevUI |
response.trace.complete | HostedFileContent | DevUI |
response.trace.complete | HostedVectorStoreContent | DevUI |
*Uses standard OpenAI event structure but carries DevUI-specific ExecutorActionItem payload
- OpenAI = Standard OpenAI Responses API event types
- DevUI = Custom event types specific to Agent Framework (e.g., workflows, traces, function approvals)
OpenAI Responses API Compliance
DevUI follows the OpenAI Responses API specification for maximum compatibility:
OpenAI Standard Event Types Used:
ResponseOutputItemAddedEvent - Output item notifications (function calls, images, files, data)
ResponseOutputItemDoneEvent - Output item completion notifications
Response.usage - Token usage (in final response, not streamed)
Custom DevUI Extensions:
response.output_item.added with custom item types:
ResponseOutputImage - Agent-generated images (inline display)
ResponseOutputFile - Agent-generated files (inline display)
ResponseOutputData - Agent-generated structured data (inline display)
response.function_approval.requested - Function approval requests (for interactive approval workflows)
response.function_approval.responded - Function approval responses (user approval/rejection)
response.function_result.complete - Server-side function execution results
response.workflow_event.complete - Agent Framework workflow events
response.trace.complete - Execution traces and internal content (DataContent, UriContent, hosted files/stores)
These custom extensions are clearly namespaced and can be safely ignored by standard OpenAI clients. Note that DevUI also uses standard OpenAI events with custom payloads (e.g., ExecutorActionItem within response.output_item.added).
Entity Management
GET /v1/entities - List discovered agents/workflows
GET /v1/entities/{entity_id}/info - Get detailed entity information
POST /v1/entities/{entity_id}/reload - Hot reload entity (for development)
Execution (OpenAI Responses API)
POST /v1/responses - Execute agent/workflow (streaming or sync)
Conversations (OpenAI Standard)
POST /v1/conversations - Create conversation
GET /v1/conversations/{id} - Get conversation
POST /v1/conversations/{id} - Update conversation metadata
DELETE /v1/conversations/{id} - Delete conversation
GET /v1/conversations?agent_id={id} - List conversations (DevUI extension)
POST /v1/conversations/{id}/items - Add items to conversation
GET /v1/conversations/{id}/items - List conversation items
GET /v1/conversations/{id}/items/{item_id} - Get conversation item
Health
GET /health - Health check
Security
DevUI is designed as a sample application for local development and should not be exposed to untrusted networks without proper authentication.
For production deployments:
devui ./agents --mode user --auth --host 0.0.0.0
This restricts developer APIs (reload, deployment, entity details) and requires Bearer token authentication.
Security features:
- User mode restricts developer-facing APIs
- Optional Bearer token authentication via
--auth
- Only loads entities from local directories or in-memory registration
- No remote code execution capabilities
- Binds to localhost (127.0.0.1) by default
Best practices:
- Use
--mode user --auth for any deployment exposed to end users
- Review all agent/workflow code before running
- Only load entities from trusted sources
- Use
.env files for sensitive credentials (never commit them)
Implementation
- Discovery:
agent_framework_devui/_discovery.py
- Execution:
agent_framework_devui/_executor.py
- Message Mapping:
agent_framework_devui/_mapper.py
- Conversations:
agent_framework_devui/_conversations.py
- API Server:
agent_framework_devui/_server.py
- CLI:
agent_framework_devui/_cli.py
Examples
See working implementations in python/samples/getting_started/devui/
License
MIT