home-assistant.io/source/_integrations/mcp_server.markdown

title, description, ha_category, ha_release, ha_iot_class, ha_config_flow, ha_codeowners, ha_domain, ha_integration_type, related, ha_quality_scale

title	description	ha_category	ha_release	ha_iot_class	ha_config_flow	ha_codeowners	ha_domain	ha_integration_type	related	ha_quality_scale
Model Context Protocol Server	Instructions on how to add a Model Context Protocol Server to Home Assistant.	Voice	2025.2	Local Push	true	@allenporter	mcp_server	service	docs title /integrations/conversation/ Conversation	silver

The Model Context Protocol is an open protocol that standardizes how applications provide context to LLMs. The Model Context Protocol Server (MCP) integration enables using Home Assistant to provide context for MCP LLM Client Applications. For example, you can control your lights from Claude Desktop, or expose your Google Tasks to-do list as a tool.

Controlling Home Assistant is done by providing MCP clients access to the Assist API of Home Assistant. You can control what devices and entities it can access from the {% my voice_assistants title="exposed entities page" %}.

Prerequisites

• You need an MCP client LLM Application such as Claude for Desktop.
• If your client does not support remote servers, you need an additional local MCP server remote gateway.

For detailed configuration instructions, refer to the Client configuration section.

{% include integrations/config_flow.md %}

Configuration options

The integration provides the following configuration options:

{% configuration_basic %} Control Home Assistant: description: If MCP clients are allowed to control Home Assistant. Clients can only control or provide information about entities that are exposed to it. {% endconfiguration_basic %}

Architecture overview

This integration can provide similar functionality as other LLM-based conversation agents (for example Anthropic, Google Generative AI, Ollama, Open AI). In those conversation agents, Home Assistant is the client and prepares the available tools and passes them into the LLM with a prompt.

The Model Context Protocol follows a different pattern: An LLM application acts as a client and can connect to multiple MCP servers to provide context. See the Model Context Protocol Introduction for more details.

The Home Assistant Model Context Protocol Server integration implements the Streamable HTTP protocol allowing client-to-server communication using the stateless protocol. Some MCP clients only support stdio transport, and directly run an MCP server as a local command line tool. You can use an MCP proxy server like mcp-proxy to act as a gateway to the Home Assistant MCP SSE server.

Client configuration

The Model Context Protocol specification has recently defined standards for authorization and connecting to remote servers. The standards are a work in progress and so some clients may not support the latest functionality, and the specification will likely continue to evolve.

The Home Assistant MCP server is exposed as /api/mcp and requires the client to provide an authentication token.

Access control

OAuth

The Model Context Protocol supports OAuth for Authorization and is fully supported by Home Assistant's Authentication API. MCP Clients that support OAuth can use this to allow you to give the client access to your Home Assistant MCP server.

Home Assistant has adopted IndieAuth and does not require you to pre-define an OAuth Client ID. Instead, the Client ID is the base of the redirect URL.

• Client ID: If your redirect-uri is https://www.example.com/mcp/redirect, your client ID should be https://www.example.com.
• Client Secret: This is not used by Home Assistant and can be ignored or set to any value.

Long-Lived Access Tokens

Some MCP clients may not support OAuth, but may support access tokens. You may create a Long-lived access token to allow the client to access the API.

1. Visit your account profile settings, under the Security tab. {% my profile badge %}.

2. Create a Long-lived access token

3. Copy the access token to use when configuring the MCP client LLM application.

For more information about Authentication in Home Assistant, refer to the Authentication documentation.

Example: Claude for Desktop

Claude for Desktop now supports remote MCP servers, making it extremely easy to connect to your Home Assistant instance:

1. Download Claude for Desktop and log in.

2. Click your profile name, select Settings, and go to Connectors.

3. Click Add Custom Connector.

4. Enter the following details:

   • Name: "Home Assistant" (or any more descriptive name you prefer)
   • Remote MCP Server URL: https://<your_home_assistant_url>/api/mcp
   • Under advanced settings:
     • OAuth Client ID: https://claude.ai
     • OAuth Client Secret: Leave this blank

5. Click OK. Now click Connect next to the entry created with the name you provided above.

6. Log in to your Home Assistant instance and allow the redirect back to Claude Desktop.

7. You can now enable tools from Home Assistant when chatting with Claude, allowing you to control Home Assistant in a similar way to how you control it through the Voice Assistant. Claude will ask you for permission before calling any tools.

   

Example: Cursor

1. Download and install Cursor.
2. Install mcp-proxy following the instructions in the README. For example, uv tool install git+https://github.com/sparfenyuk/mcp-proxy.
3. Open the main Cursor Settings and select MCP.
4. Click Add new global MCP server and add the Home Assistant server configuration:

    {
      "mcpServers": {
        "Home Assistant": {
          "command": "mcp-proxy",
          "args": [
            "--transport=streamablehttp",
            "--stateless",
            "http://localhost:8123/api/mcp"
          ],
          "env": {
            "API_ACCESS_TOKEN": "<your_access_token_here>"
          }
        }
      }
    }
   

5. Save your mcp.json file. You can also find this file in the $HOME/.cursor/mcp.json directory.
6. Restart Cursor and return to the MCP settings. You should see the Home Assistant server in the list. The indicator should be green.
7. In chat agent mode (Ctrl+I), ask it to control your home and the tool should be used.

Supported functionality

Tools

MCP Tools enable LLMs to perform actions through Home Assistant. The tools used by the configured LLM API are exposed.

Prompts

The MCP Prompts provided inform LLMs how to call the tools. The tools used by the configured LLM API are exposed.

Known Limitations

The Home Assistant Model Context Protocol integration currently only supports a subset of MCP features:

Feature	Supported by Home Assistant
Prompts	✅
Tools	✅
Resources	❌
Sampling	❌
Notifications	❌

Troubleshooting

This section has troubleshooting information for Claude for Desktop since it is the primary client. Also see Debugging in Claude Desktop.

LLM client cannot connect to Home Assistant MCP server

Symptom: Failed to start MCP server: Could not start MCP server Home Assistant

When trying to configure a client like Claude for Desktop to talk to Home Assistant, the app shows a message like "Failed to start MCP server: Could not start MCP server Home Assistant"

Description

This means that the local MCP server mcp-proxy could not start.

Resolution

Verify the command line arguments in the claude_desktop_config.json are correct. You may try to run the command manually to verify that the command can be found.

Symptom: “MCP server Home Assistant disconnected” or "Could not attach to MCP server Home Assistant"

When trying to configure a client like Claude Desktop to talk to Home Assistant, the app shows a message like "MCP server Home Assistant disconnected" or "Could not attach to MCP server Home Assistant".

Description

This means the MCP server has started, however the MCP server is having trouble communicating with Home Assistant, or the MCP server in Home Assistant is not configured.

Resolution

To understand the root cause, first check debug logs on the client. For example in Claude for Desktop:

1. Visit Settings....
2. Select Developer.
3. Select the Home Assistant MCP server.
4. Select Open Logs Folder.
5. View mcp-server-Home Assistant.log. These are known problems and their resolution:
   • Client error '404 Not Found' for url 'http://localhost:8123/api/mcp': this means the MCP Server integration is not configured in Home Assistant.
   • Client error '401 Unauthorized' for url 'http://localhost:8123/api/mcp': this means that the long live access token is not correct. ...

Removing the integration

This integration can be removed by following these steps:

{% include integrations/remove_device_service.md %}