feat: allow selecting multiple MCP servers

custom_components/custom_conversation/api.py

@@ -41,7 +41,7 @@
 
 
 class CustomLLMAPI(llm.API):
-    """An API for the Custom Conversation integration to use to call Home Assistant services."""
+    """MCP server for Custom Conversation (intents, scripts, and managed prompts as LLM tools)."""
 
     def __init__(
         self,
@@ -50,7 +50,7 @@ def __init__(
         conversation_config_entry: ConfigEntry | None = None,
     ) -> None:
         """Initialize the API."""
-        super().__init__(hass=hass, id=LLM_API_ID, name="Custom Conversation LLM API")
+        super().__init__(hass=hass, id=LLM_API_ID, name="Custom Conversation MCP server")
         self.cached_slugify = cache(
             partial(unicode_slug.slugify, separator="_", lowercase=False)
         )
@@ -67,7 +67,7 @@ def set_langfuse_client(self, langfuse_client: Any) -> None:
     async def async_get_api_instance(
         self, llm_context: llm.LLMContext
     ) -> llm.APIInstance:
-        """Return an instance of the Custom Conversation LLM API."""
+        """Return an instance of this integration's MCP server API."""
         if llm_context.assistant:
             exposed_entities: dict | None = _get_exposed_entities(
                 self.hass, llm_context.assistant

custom_components/custom_conversation/cc_llm.py

@@ -14,7 +14,7 @@
 
 from . import CustomConversationConfigEntry
 from .api import CustomLLMAPI
-from .const import DOMAIN, LLM_API_ID, LOGGER
+from .const import DOMAIN, LLM_API_ID, LOGGER, coerce_llm_hass_api_ids
 from .prompt_manager import PromptContext, PromptManager
 
 
@@ -25,7 +25,7 @@ async def async_update_llm_data(
     config_entry: CustomConversationConfigEntry,
     chat_log: ChatLog,
     prompt_manager: PromptManager,
-    llm_api_name: str | None = None,
+    llm_hass_api: str | list[str] | None = None,
 ):
     """Process the incoming message for the LLM.
 
@@ -53,36 +53,44 @@ async def async_update_llm_data(
         user_name = user.name
 
     llm_api: llm.APIInstance | None = None
+    api_ids = coerce_llm_hass_api_ids(llm_hass_api)
 
-    if llm_api_name:
+    if api_ids:
         try:
-            if llm_api_name == LLM_API_ID:
-                LOGGER.debug("Using Custom LLM API for request")
-                api_instance = CustomLLMAPI(
-                    hass,
-                    user_name,
-                    conversation_config_entry=config_entry,
-                )
-                if (
-                    langfuse_client := hass.data.get(DOMAIN,{})
-                    .get(config_entry.entry_id,{})
-                    .get("langfuse_client")
-                ):
-                    LOGGER.debug("Setting langfuse client for Custom LLM API")
-                    api_instance.set_langfuse_client(langfuse_client)
-                llm_api = await api_instance.async_get_api_instance(llm_context)
+            registered = {api.id: api for api in llm.async_get_apis(hass)}
+            apis_to_merge: list[llm.API] = []
+            for api_id in api_ids:
+                if api_id == LLM_API_ID:
+                    custom_api = CustomLLMAPI(
+                        hass,
+                        user_name,
+                        conversation_config_entry=config_entry,
+                    )
+                    if (
+                        langfuse_client := hass.data.get(DOMAIN, {})
+                        .get(config_entry.entry_id, {})
+                        .get("langfuse_client")
+                    ):
+                        custom_api.set_langfuse_client(langfuse_client)
+                    apis_to_merge.append(custom_api)
+                    LOGGER.debug("Including Custom LLM API in merge")
+                elif api_id in registered:
+                    apis_to_merge.append(registered[api_id])
+                    LOGGER.debug("Including LLM API %s in merge", api_id)
+                else:
+                    raise HomeAssistantError(f"API {api_id} not found")
+
+            if len(apis_to_merge) == 1:
+                llm_api = await apis_to_merge[0].async_get_api_instance(llm_context)
             else:
-                LOGGER.debug("Using LLM API with ID %s", llm_api_name)
-                llm_api = await llm.async_get_api(
-                    hass,
-                    llm_api_name,
-                    llm_context,
+                llm_api = await llm.MergedAPI(apis_to_merge).async_get_api_instance(
+                    llm_context
                 )
 
         except HomeAssistantError as err:
             LOGGER.error(
-                "Error getting LLM API %s for %s: %s",
-                llm_api_name,
+                "Error getting LLM APIs %s for %s: %s",
+                api_ids,
                 DOMAIN,
                 err,
             )
@@ -92,10 +100,10 @@ async def async_update_llm_data(
                 "Error preparing LLM API",
             )
             raise ConverseError(
-                    f"Error getting LLM API {llm_api_name}",
-                    conversation_id=chat_log.conversation_id,
-                    response=intent_response,
-                ) from err
+                f"Error getting LLM APIs {api_ids}",
+                conversation_id=chat_log.conversation_id,
+                response=intent_response,
+            ) from err
     prompt_object = None
     try:
         prompt_context = PromptContext(
@@ -126,15 +134,16 @@ async def async_update_llm_data(
                 prompt_object, prompt = prompt
             LOGGER.debug("Base prompt: %s", prompt)
         else:
-            # We're using a different API, so we need to combine the base prompt with
-            # the API prompt
+            # Non-custom API (or merged APIs): base prompt plus API / merged API text
             base_prompt = await prompt_manager.async_get_base_prompt(
                 prompt_context,
                 config_entry,
             )
-            prompt_parts = [base_prompt]
-            prompt_parts.append(llm_api.api_prompt)
-            prompt = "\n".join(prompt_parts)
+            if isinstance(base_prompt, tuple):
+                prompt_object, base_text = base_prompt
+            else:
+                base_text = base_prompt
+            prompt = "\n".join([base_text, llm_api.api_prompt])
             LOGGER.debug("Combined prompt: %s", prompt)
 
     except TemplateError as err:

custom_components/custom_conversation/config_flow.py

@@ -64,6 +64,7 @@
     CONF_TOP_P,
     CONFIG_VERSION,
     CONFIGURING_SECONDARY_PROVIDER,
+    coerce_llm_hass_api_ids,
     DEFAULT_API_PROMPT_BASE,
     DEFAULT_API_PROMPT_DEVICE_KNOWN_LOCATION,
     DEFAULT_API_PROMPT_DEVICE_UNKNOWN_LOCATION,
@@ -83,7 +84,6 @@
 _LOGGER = LOGGER
 
 DEFAULT_OPTIONS = {
-    CONF_LLM_HASS_API: "none",
     CONF_AGENTS_SECTION: {
         CONF_ENABLE_HASS_AGENT: True,
         CONF_ENABLE_LLM_AGENT: True,
@@ -505,9 +505,13 @@ async def async_step_init(
             # Process user input before saving
             processed_input = {**user_input}  # Start with a copy
 
-            # Handle potential "none" value for Hass API control
-            if processed_input.get(CONF_LLM_HASS_API) == "none":
-                processed_input.pop(CONF_LLM_HASS_API, None)  # Remove if 'none'
+            # MCP server ids (CONF_LLM_HASS_API): store list or omit when none selected
+            llm_apis = processed_input.get(CONF_LLM_HASS_API)
+            normalized = coerce_llm_hass_api_ids(llm_apis)
+            if normalized:
+                processed_input[CONF_LLM_HASS_API] = normalized
+            else:
+                processed_input.pop(CONF_LLM_HASS_API, None)
 
             # Handle empty ignored intents - use default
             ignored_intents_section = processed_input.get(
@@ -552,12 +556,21 @@ async def async_step_init(
                     CONF_MAX_TOKENS,
                     default=options.get(CONF_MAX_TOKENS, DEFAULT_MAX_TOKENS),
                 ): vol.All(vol.Coerce(int), vol.Range(min=1)),
-                # Hass API Control
+                # MCP servers (multiple merged like core conversation)
                 vol.Optional(
                     CONF_LLM_HASS_API,
-                    description={"suggested_value": options.get(CONF_LLM_HASS_API)},
-                    default="none",
-                ): SelectSelector(SelectSelectorConfig(options=hass_apis)),
+                    description={
+                        "suggested_value": coerce_llm_hass_api_ids(
+                            options.get(CONF_LLM_HASS_API)
+                        )
+                        or []
+                    },
+                    default=[],
+                ): SelectSelector(
+                    SelectSelectorConfig(
+                        options=hass_apis, multiple=True, sort=True
+                    )
+                ),
                 # Agent Section
                 vol.Required(CONF_AGENTS_SECTION): section(
                     vol.Schema(
@@ -756,15 +769,11 @@ async def async_step_init(
         )
 
     def _get_hass_apis(self, hass: HomeAssistant) -> list[SelectOptionDict]:
-        """Get available Home Assistant LLM APIs."""
-        hass_apis: list[SelectOptionDict] = [
-            SelectOptionDict(label="No control", value="none")
-        ]
-        hass_apis.extend(
+        """Get registered MCP servers / LLM tool APIs for multi-select."""
+        return [
             SelectOptionDict(label=api.name, value=api.id)
             for api in llm.async_get_apis(hass)
-        )
-        return hass_apis
+        ]
 
     async def _get_intents(self, hass: HomeAssistant) -> list[SelectOptionDict]:
         """Get available intents."""

custom_components/custom_conversation/const.py

@@ -1,6 +1,9 @@
 """Constants for the Custom Conversation integration."""
 
+from __future__ import annotations
+
 import logging
+from typing import Any
 
 DOMAIN = "custom_conversation"
 LOGGER = logging.getLogger(__package__)
@@ -117,3 +120,24 @@
 # Deprecated constants for migrations only
 CONF_CHAT_MODEL = "chat_model"
 CONF_BASE_URL = "base_url"
+
+
+def coerce_llm_hass_api_ids(raw: Any) -> list[str] | None:
+    """Normalize CONF_LLM_HASS_API (MCP server / LLM API ids) from options."""
+    if raw is None:
+        return None
+    if isinstance(raw, str):
+        if raw in ("", "none"):
+            return None
+        return [raw]
+    if isinstance(raw, list):
+        out: list[str] = []
+        seen: set[str] = set()
+        for item in raw:
+            if not item or item == "none":
+                continue
+            if item not in seen:
+                seen.add(item)
+                out.append(item)
+        return out or None
+    return None

custom_components/custom_conversation/conversation.py

@@ -58,6 +58,7 @@
     CONF_SECONDARY_PROVIDER,
     CONF_SECONDARY_PROVIDER_ENABLED,
     CONF_TEMPERATURE,
+    coerce_llm_hass_api_ids,
     CONF_TOP_P,
     CONVERSATION_ENDED_EVENT,
     CONVERSATION_ERROR_EVENT,
@@ -341,7 +342,7 @@ def __init__(
             model="Custom Conversation",
             entry_type=dr.DeviceEntryType.SERVICE,
         )
-        if self.entry.options.get(CONF_LLM_HASS_API):
+        if coerce_llm_hass_api_ids(self.entry.options.get(CONF_LLM_HASS_API)):
             self._attr_supported_features = (
                 conversation.ConversationEntityFeature.CONTROL
             )
@@ -579,16 +580,13 @@ async def _async_handle_message_with_llm(
 
         try:
             LOGGER.debug("Updating LLM Data")
-            llm_api = self.entry.options.get(CONF_LLM_HASS_API)
-            if llm_api == "none":
-                llm_api = None
             prompt_object = await async_update_llm_data(
                 self.hass,
                 user_input,
                 self.entry,
                 chat_log,
                 self.prompt_manager,
-                llm_api,
+                self.entry.options.get(CONF_LLM_HASS_API),
             )
             if prompt_object:
                 LOGGER.debug(

custom_components/custom_conversation/strings.json

@@ -58,22 +58,23 @@
       "init": {
         "data": {
           "instructions_prompt": "Instructions",
-          "llm_hass_api": "Choose the API to expose to the LLM"
+          "llm_hass_api": "MCP servers for the model"
         },
         "data_description": {
-          "prompt": "Instruct how the LLM should respond. This can be a template."
+          "prompt": "Instruct how the LLM should respond. This can be a template.",
+          "llm_hass_api": "Each option is an MCP server available to conversation agents in Home Assistant. Assist is the built-in server from core; the MCP Client integration registers additional servers. Custom Conversation MCP server is this integration's server. Pick one or more; their tools and instructions are merged for the LLM."
         },
         "sections": {
           "ignored_intents_section": {
             "name": "Ignored Intents",
-            "description": "Configure which intents should be ignored by the Custom LLM API.\nThose recommended by the current Home Assistant version are marked.",
+            "description": "Configure which intents this integration's MCP server should not expose as tools.\nThose recommended by the current Home Assistant version are marked.",
             "data": {
               "ignored_intents": "Ignored Intents"
             }
           },
           "agents": {
-            "name": "Custom LLM API Agents",
-            "description": "Configure which agents are enabled for the Custom LLM API.\nEnabling both will try to resolve intents locally first,\nand then fall back to the configured LLM.",
+            "name": "Conversation agents",
+            "description": "Configure how requests are handled before the configured model runs.\nEnabling both tries the Home Assistant agent first, then the LLM agent.",
             "data": {
               "enable_home_assistant_agent": "Enable Home Assistant Agent",
               "enable_llm_agent": "Enable LLM Agent"
@@ -131,7 +132,7 @@
               "enable_langfuse": "Enable Langfuse for prompt management",
               "base_prompt_id": "The ID Langfuse prompt to use when the API is not enabled.\nHome assistant templating is not supported, but the variables '{{current_time}}' and '{{current_date}}', '{{ha_name}}' and '{{user_name}}' are available.",
               "base_prompt_label": "The label to select the version of the base prompt (ie, 'production', or 'latest')",
-              "api_prompt_id": "The ID of the Langfuse  prompt to use when the custom LLM API is enabled.\nNote that because Langfuse does not currently support combining multiple prompts, this will be the only prompt sent, it will not be combined with the one above as is the case with the non-Langfuse support.\nIn addition to the above variables, '{{location}}', '{{supports_timers}}' and '{{exposed_entities}}' are available.",
+              "api_prompt_id": "The ID of the Langfuse prompt to use when this integration's MCP server (Custom Conversation MCP server) is selected under MCP servers for the model.\nNote that because Langfuse does not currently support combining multiple prompts, this will be the only prompt sent, it will not be combined with the one above as is the case with the non-Langfuse support.\nIn addition to the above variables, '{{location}}', '{{supports_timers}}' and '{{exposed_entities}}' are available.",
               "api_prompt_label": "The label to select the version of the API prompt (ie, 'production', or 'latest')",
               "langfuse_host": "The host of the Langfuse API",
               "langfuse_public_key": "The public key for the Langfuse API",

custom_components/custom_conversation/translations/en.json

@@ -58,22 +58,23 @@
       "init": {
         "data": {
           "instructions_prompt": "Instructions",
-          "llm_hass_api": "Choose the API to expose to the LLM"
+          "llm_hass_api": "MCP servers for the model"
         },
         "data_description": {
-          "prompt": "Instruct how the LLM should respond. This can be a template."
+          "prompt": "Instruct how the LLM should respond. This can be a template.",
+          "llm_hass_api": "Each option is an MCP server available to conversation agents in Home Assistant. Assist is the built-in server from core; the MCP Client integration registers additional servers. Custom Conversation MCP server is this integration's server. Pick one or more; their tools and instructions are merged for the LLM."
         },
         "sections": {
           "ignored_intents_section": {
             "name": "Ignored Intents",
-            "description": "Configure which intents should be ignored by the Custom LLM API.\nThose recommended by the current Home Assistant version are marked.",
+            "description": "Configure which intents this integration's MCP server should not expose as tools.\nThose recommended by the current Home Assistant version are marked.",
             "data": {
               "ignored_intents": "Ignored Intents"
             }
           },
           "agents": {
-            "name": "Custom LLM API Agents",
-            "description": "Configure which agents are enabled for the Custom LLM API.\nEnabling both will try to resolve intents locally first,\nand then fall back to the configured LLM.",
+            "name": "Conversation agents",
+            "description": "Configure how requests are handled before the configured model runs.\nEnabling both tries the Home Assistant agent first, then the LLM agent.",
             "data": {
               "enable_home_assistant_agent": "Enable Home Assistant Agent",
               "enable_llm_agent": "Enable LLM Agent"
@@ -131,7 +132,7 @@
               "enable_langfuse": "Enable Langfuse for prompt management",
               "base_prompt_id": "The ID Langfuse prompt to use when the API is not enabled.\nHome assistant templating is not supported, but the variables '{{current_time}}' and '{{current_date}}', '{{ha_name}}' and '{{user_name}}' are available.",
               "base_prompt_label": "The label to select the version of the base prompt (ie, 'production', or 'latest')",
-              "api_prompt_id": "The ID of the Langfuse  prompt to use when the custom LLM API is enabled.\nNote that because Langfuse does not currently support combining multiple prompts, this will be the only prompt sent, it will not be combined with the one above as is the case with the non-Langfuse support.\nIn addition to the above variables, '{{location}}', '{{supports_timers}}' and '{{exposed_entities}}' are available.",
+              "api_prompt_id": "The ID of the Langfuse prompt to use when this integration's MCP server (Custom Conversation MCP server) is selected under MCP servers for the model.\nNote that because Langfuse does not currently support combining multiple prompts, this will be the only prompt sent, it will not be combined with the one above as is the case with the non-Langfuse support.\nIn addition to the above variables, '{{location}}', '{{supports_timers}}' and '{{exposed_entities}}' are available.",
               "api_prompt_label": "The label to select the version of the API prompt (ie, 'production', or 'latest')",
               "langfuse_host": "The host of the Langfuse API",
               "langfuse_public_key": "The public key for the Langfuse API",

unit_tests/test_api.py

@@ -138,7 +138,7 @@ async def test_custom_llm_api_init(hass, config_entry):
     assert api._request_user_name == "Test User"
     assert api.conversation_config_entry is config_entry
     assert api.id == LLM_API_ID
-    assert api.name == "Custom Conversation LLM API"
+    assert api.name == "Custom Conversation MCP server"
 
 def test_custom_llm_api_set_langfuse_client(custom_llm_api, mock_prompt_manager):
     """Test setting the Langfuse client."""