mcp-run-python

# Web Chat UI Pydantic AI includes a built-in web chat interface that you can use to interact with your agents through a browser.  For CLI usage with `clai web`, see the [CLI - Web Chat UI documentation](cli.md#web-chat-ui). ## Installation Install the `web` extra (installs Starlette and Uvicorn): ```bash pip/uv-add 'pydantic-ai-slim[web]' ``` ## Basic Usage Create a web app from an agent instance using [`Agent.to_web()`][pydantic_ai.Agent.to_web]: ```python from pydantic_ai import Agent agent = Agent('openai:gpt-5', instructions='You are a helpful assistant.') @agent.tool_plain def get_weather(city: str) -> str: return f'The weather in {city} is sunny' app = agent.to_web() ``` Run the app with any ASGI server: ```bash uvicorn my_module:app --host 127.0.0.1 --port 7932 ``` ## Configuring Models You can specify additional models to make available in the UI. Models can be provided as a list of model names/instances or a dictionary mapping display labels to model names/instances. ```python from pydantic_ai import Agent from pydantic_ai.models.anthropic import AnthropicModel # Model with custom configuration anthropic_model = AnthropicModel('claude-sonnet-4-5') agent = Agent('openai:gpt-5') app = agent.to_web( models=['openai:gpt-5', anthropic_model], ) # Or with custom display labels app = agent.to_web( models={'GPT 5': 'openai:gpt-5', 'Claude': anthropic_model}, ) ``` ## Builtin Tool Support You can specify a list of [builtin tools](builtin-tools.md) that will be shown as options to the user, if the selected model supports them: ```python from pydantic_ai import Agent from pydantic_ai.builtin_tools import CodeExecutionTool, WebSearchTool agent = Agent('openai:gpt-5') app = agent.to_web( models=['anthropic:claude-sonnet-4-5'], builtin_tools=[CodeExecutionTool(), WebSearchTool()], ) ``` !!! note "Memory Tool" The `memory` builtin tool is not supported via `to_web()` or `clai web`. If your agent needs memory, configure the [`MemoryTool`][pydantic_ai.builtin_tools.MemoryTool] directly on the agent at construction time. ## Extra Instructions You can pass extra instructions that will be included in each agent run: ```python from pydantic_ai import Agent agent = Agent('openai:gpt-5') app = agent.to_web(instructions='Always respond in a friendly tone.') ``` ## Reserved Routes The web UI app uses the following routes which should not be overwritten: - `/` and `/{id}` - Serves the chat UI - `/api/chat` - Chat endpoint (POST, OPTIONS) - `/api/configure` - Frontend configuration (GET) - `/api/health` - Health check (GET) The app cannot currently be mounted at a subpath (e.g., `/chat`) because the UI expects these routes at the root. You can add additional routes to the app, but avoid conflicts with these reserved paths.