feat: allow user to register model alias explicitly, tests

# What does this PR do?

Context: https://github.com/llamastack/llama-stack/discussions/3483

This PR enables the registering `provider_model_id` as the model identifier without breaking backward compatibility.


## Test Plan
todo
# What does this PR do?


## Test Plan

benchmarking/k8s-benchmark/stack_run_config.yaml

@@ -116,7 +116,8 @@ models:
   model_id: all-MiniLM-L6-v2
   provider_id: sentence-transformers
   model_type: embedding
-- model_id: ${env.INFERENCE_MODEL}
+- use_provider_model_id_as_id: true
+  provider_model_id: ${env.INFERENCE_MODEL}
   provider_id: vllm-inference
   model_type: llm
 shields:

llama_stack/apis/models/models.py

@@ -10,9 +10,12 @@ from typing import Any, Literal, Protocol, runtime_checkable
 from pydantic import BaseModel, ConfigDict, Field, field_validator
 
 from llama_stack.apis.resource import Resource, ResourceType
+from llama_stack.log import get_logger
 from llama_stack.providers.utils.telemetry.trace_protocol import trace_protocol
 from llama_stack.schema_utils import json_schema_type, webmethod
 
+logger = get_logger(name=__name__, category="core")
+
 
 class CommonModelFields(BaseModel):
     metadata: dict[str, Any] = Field(
@@ -68,11 +71,36 @@ class Model(CommonModelFields, Resource):
 
 
 class ModelInput(CommonModelFields):
-    model_id: str
+    """A model input for registering a model.
-    provider_id: str | None = None
+
+    :param provider_model_id: The identifier of the model in the provider.
+    :param provider_id: The identifier of the provider.
+    :param model_type: The type of model to register.
+    :param model_id: The identifier of the model to register. If model_id == provider_model_id, provider_id/provider_model_id will be used as the identifier. Otherwise,
+        model_id will be used as the identifier.
+        The behavior of this field will soon change to "always use model_id as the identifier".
+    :param use_provider_model_id_as_id: Set to true to use provider_model_id as the identifier. Use model_id if you want to use a different identifier.
+    """
+
     provider_model_id: str | None = None
+    provider_id: str | None = None
     model_type: ModelType | None = ModelType.llm
     model_config = ConfigDict(protected_namespaces=())
+    # TODO: update behavior of this field to always be the identifier
+    model_id: str | None = None
+    use_provider_model_id_as_id: bool = False
+
+    def model_post_init(self, __context: Any) -> None:
+        if self.model_id is None and self.provider_model_id is None:
+            raise ValueError("provider_model_id must be provided")
+
+        if self.model_id == self.provider_model_id:
+            logger.warning(
+                f"`model_id` is now optional. The behavior of this field will change if model_id == provider_model_id. Please remove `model_id` and use `provider_model_id` instead.: {self.model_id}"
+            )
+
+        if self.use_provider_model_id_as_id and self.model_id:
+            raise ValueError(f"use_provider_model_id_as_id and model_id cannot be provided together: {self.model_id}")
 
 
 class ListModelsResponse(BaseModel):

llama_stack/core/datatypes.py

@@ -26,6 +26,7 @@ from llama_stack.apis.tools import Tool, ToolGroup, ToolGroupInput, ToolRuntime
 from llama_stack.apis.vector_dbs import VectorDB, VectorDBInput
 from llama_stack.apis.vector_io import VectorIO
 from llama_stack.core.access_control.datatypes import AccessRule
+from llama_stack.log import LoggingConfig
 from llama_stack.providers.datatypes import Api, ProviderSpec
 from llama_stack.providers.utils.kvstore.config import KVStoreConfig, SqliteKVStoreConfig
 from llama_stack.providers.utils.sqlstore.sqlstore import SqlStoreConfig
@@ -185,14 +186,6 @@ class DistributionSpec(BaseModel):
     )
 
 
-class LoggingConfig(BaseModel):
-    category_levels: dict[str, str] = Field(
-        default_factory=dict,
-        description="""
- Dictionary of different logging configurations for different portions (ex: core, server) of llama stack""",
-    )
-
-
 class OAuth2JWKSConfig(BaseModel):
     # The JWKS URI for collecting public keys
     uri: str

llama_stack/core/routing_tables/models.py

@@ -69,11 +69,12 @@ class ModelsRoutingTable(CommonRoutingTableImpl, Models):
 
     async def register_model(
         self,
-        model_id: str,
+        model_id: str | None = None,
         provider_model_id: str | None = None,
         provider_id: str | None = None,
         metadata: dict[str, Any] | None = None,
         model_type: ModelType | None = None,
+        use_provider_model_id_as_id: bool = False,
     ) -> Model:
         if provider_id is None:
             # If provider_id not specified, use the only provider if it supports this model
@@ -85,6 +86,17 @@ class ModelsRoutingTable(CommonRoutingTableImpl, Models):
                     "Use the provider_id as a prefix to disambiguate, e.g. 'provider_id/model_id'."
                 )
 
+        if model_id is None and provider_model_id is None:
+            raise ValueError("provider_model_id must be provided")
+
+        if model_id == provider_model_id:
+            logger.warning(
+                f"`model_id` is now optional. Please remove `{model_id=}` and use `{provider_model_id=}` instead."
+            )
+
+        if use_provider_model_id_as_id and model_id:
+            raise ValueError(f"use_provider_model_id_as_id and model_id cannot be provided together: {model_id=}")
+
         provider_model_id = provider_model_id or model_id
         metadata = metadata or {}
         model_type = model_type or ModelType.llm
@@ -94,8 +106,9 @@ class ModelsRoutingTable(CommonRoutingTableImpl, Models):
         # an identifier different than provider_model_id implies it is an alias, so that
         # becomes the globally unique identifier. otherwise provider_model_ids can conflict,
         # so as a general rule we must use the provider_id to disambiguate.
-
+        if use_provider_model_id_as_id:
-        if model_id != provider_model_id:
+            identifier = provider_model_id
+        elif model_id and model_id != provider_model_id:
             identifier = model_id
         else:
             identifier = f"{provider_id}/{provider_model_id}"

llama_stack/distributions/dell/dell.py

@@ -79,15 +79,15 @@ def get_distribution_template() -> DistributionTemplate:
     )
 
     inference_model = ModelInput(
-        model_id="${env.INFERENCE_MODEL}",
+        provider_model_id="${env.INFERENCE_MODEL}",
         provider_id="tgi0",
     )
     safety_model = ModelInput(
-        model_id="${env.SAFETY_MODEL}",
+        provider_model_id="${env.SAFETY_MODEL}",
         provider_id="tgi1",
     )
     embedding_model = ModelInput(
-        model_id="all-MiniLM-L6-v2",
+        provider_model_id="all-MiniLM-L6-v2",
         provider_id="sentence-transformers",
         model_type=ModelType.embedding,
         metadata={

llama_stack/distributions/dell/run-with-safety.yaml

@@ -103,18 +103,21 @@ inference_store:
   db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/dell}/inference_store.db
 models:
 - metadata: {}
-  model_id: ${env.INFERENCE_MODEL}
+  provider_model_id: ${env.INFERENCE_MODEL}
   provider_id: tgi0
   model_type: llm
+  use_provider_model_id_as_id: false
 - metadata: {}
-  model_id: ${env.SAFETY_MODEL}
+  provider_model_id: ${env.SAFETY_MODEL}
   provider_id: tgi1
   model_type: llm
+  use_provider_model_id_as_id: false
 - metadata:
     embedding_dimension: 384
-  model_id: all-MiniLM-L6-v2
+  provider_model_id: all-MiniLM-L6-v2
   provider_id: sentence-transformers
   model_type: embedding
+  use_provider_model_id_as_id: false
 shields:
 - shield_id: ${env.SAFETY_MODEL}
 vector_dbs: []

llama_stack/distributions/dell/run.yaml

@@ -99,14 +99,16 @@ inference_store:
   db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/dell}/inference_store.db
 models:
 - metadata: {}
-  model_id: ${env.INFERENCE_MODEL}
+  provider_model_id: ${env.INFERENCE_MODEL}
   provider_id: tgi0
   model_type: llm
+  use_provider_model_id_as_id: false
 - metadata:
     embedding_dimension: 384
-  model_id: all-MiniLM-L6-v2
+  provider_model_id: all-MiniLM-L6-v2
   provider_id: sentence-transformers
   model_type: embedding
+  use_provider_model_id_as_id: false
 shields: []
 vector_dbs: []
 datasets: []

llama_stack/distributions/meta-reference-gpu/meta_reference.py

@@ -73,11 +73,11 @@ def get_distribution_template() -> DistributionTemplate:
     )
 
     inference_model = ModelInput(
-        model_id="${env.INFERENCE_MODEL}",
+        provider_model_id="${env.INFERENCE_MODEL}",
         provider_id="meta-reference-inference",
     )
     embedding_model = ModelInput(
-        model_id="all-MiniLM-L6-v2",
+        provider_model_id="all-MiniLM-L6-v2",
         provider_id="sentence-transformers",
         model_type=ModelType.embedding,
         metadata={
@@ -85,7 +85,7 @@ def get_distribution_template() -> DistributionTemplate:
         },
     )
     safety_model = ModelInput(
-        model_id="${env.SAFETY_MODEL}",
+        provider_model_id="${env.SAFETY_MODEL}",
         provider_id="meta-reference-safety",
     )
     default_tool_groups = [

llama_stack/distributions/meta-reference-gpu/run-with-safety.yaml

@@ -116,18 +116,21 @@ inference_store:
   db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/meta-reference-gpu}/inference_store.db
 models:
 - metadata: {}
-  model_id: ${env.INFERENCE_MODEL}
+  provider_model_id: ${env.INFERENCE_MODEL}
   provider_id: meta-reference-inference
   model_type: llm
+  use_provider_model_id_as_id: false
 - metadata: {}
-  model_id: ${env.SAFETY_MODEL}
+  provider_model_id: ${env.SAFETY_MODEL}
   provider_id: meta-reference-safety
   model_type: llm
+  use_provider_model_id_as_id: false
 - metadata:
     embedding_dimension: 384
-  model_id: all-MiniLM-L6-v2
+  provider_model_id: all-MiniLM-L6-v2
   provider_id: sentence-transformers
   model_type: embedding
+  use_provider_model_id_as_id: false
 shields:
 - shield_id: ${env.SAFETY_MODEL}
 vector_dbs: []

llama_stack/distributions/meta-reference-gpu/run.yaml

@@ -106,14 +106,16 @@ inference_store:
   db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/meta-reference-gpu}/inference_store.db
 models:
 - metadata: {}
-  model_id: ${env.INFERENCE_MODEL}
+  provider_model_id: ${env.INFERENCE_MODEL}
   provider_id: meta-reference-inference
   model_type: llm
+  use_provider_model_id_as_id: false
 - metadata:
     embedding_dimension: 384
-  model_id: all-MiniLM-L6-v2
+  provider_model_id: all-MiniLM-L6-v2
   provider_id: sentence-transformers
   model_type: embedding
+  use_provider_model_id_as_id: false
 shields: []
 vector_dbs: []
 datasets: []

llama_stack/distributions/nvidia/nvidia.py

@@ -53,11 +53,11 @@ def get_distribution_template() -> DistributionTemplate:
         config=NVIDIAEvalConfig.sample_run_config(),
     )
     inference_model = ModelInput(
-        model_id="${env.INFERENCE_MODEL}",
+        provider_model_id="${env.INFERENCE_MODEL}",
         provider_id="nvidia",
     )
     safety_model = ModelInput(
-        model_id="${env.SAFETY_MODEL}",
+        provider_model_id="${env.SAFETY_MODEL}",
         provider_id="nvidia",
     )
 

llama_stack/distributions/nvidia/run-with-safety.yaml

@@ -96,13 +96,15 @@ inference_store:
   db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/nvidia}/inference_store.db
 models:
 - metadata: {}
-  model_id: ${env.INFERENCE_MODEL}
+  provider_model_id: ${env.INFERENCE_MODEL}
   provider_id: nvidia
   model_type: llm
+  use_provider_model_id_as_id: false
 - metadata: {}
-  model_id: ${env.SAFETY_MODEL}
+  provider_model_id: ${env.SAFETY_MODEL}
   provider_id: nvidia
   model_type: llm
+  use_provider_model_id_as_id: false
 shields:
 - shield_id: ${env.SAFETY_MODEL}
   provider_id: nvidia

llama_stack/distributions/nvidia/run.yaml

@@ -85,88 +85,88 @@ inference_store:
   db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/nvidia}/inference_store.db
 models:
 - metadata: {}
-  model_id: meta/llama3-8b-instruct
-  provider_id: nvidia
   provider_model_id: meta/llama3-8b-instruct
-  model_type: llm
-- metadata: {}
-  model_id: meta/llama3-70b-instruct
   provider_id: nvidia
+  model_type: llm
+  use_provider_model_id_as_id: false
+- metadata: {}
   provider_model_id: meta/llama3-70b-instruct
-  model_type: llm
-- metadata: {}
-  model_id: meta/llama-3.1-8b-instruct
   provider_id: nvidia
+  model_type: llm
+  use_provider_model_id_as_id: false
+- metadata: {}
   provider_model_id: meta/llama-3.1-8b-instruct
-  model_type: llm
-- metadata: {}
-  model_id: meta/llama-3.1-70b-instruct
   provider_id: nvidia
+  model_type: llm
+  use_provider_model_id_as_id: false
+- metadata: {}
   provider_model_id: meta/llama-3.1-70b-instruct
-  model_type: llm
-- metadata: {}
-  model_id: meta/llama-3.1-405b-instruct
   provider_id: nvidia
+  model_type: llm
+  use_provider_model_id_as_id: false
+- metadata: {}
   provider_model_id: meta/llama-3.1-405b-instruct
-  model_type: llm
-- metadata: {}
-  model_id: meta/llama-3.2-1b-instruct
   provider_id: nvidia
+  model_type: llm
+  use_provider_model_id_as_id: false
+- metadata: {}
   provider_model_id: meta/llama-3.2-1b-instruct
-  model_type: llm
-- metadata: {}
-  model_id: meta/llama-3.2-3b-instruct
   provider_id: nvidia
+  model_type: llm
+  use_provider_model_id_as_id: false
+- metadata: {}
   provider_model_id: meta/llama-3.2-3b-instruct
-  model_type: llm
-- metadata: {}
-  model_id: meta/llama-3.2-11b-vision-instruct
   provider_id: nvidia
+  model_type: llm
+  use_provider_model_id_as_id: false
+- metadata: {}
   provider_model_id: meta/llama-3.2-11b-vision-instruct
-  model_type: llm
-- metadata: {}
-  model_id: meta/llama-3.2-90b-vision-instruct
   provider_id: nvidia
+  model_type: llm
+  use_provider_model_id_as_id: false
+- metadata: {}
   provider_model_id: meta/llama-3.2-90b-vision-instruct
-  model_type: llm
-- metadata: {}
-  model_id: meta/llama-3.3-70b-instruct
   provider_id: nvidia
+  model_type: llm
+  use_provider_model_id_as_id: false
+- metadata: {}
   provider_model_id: meta/llama-3.3-70b-instruct
-  model_type: llm
-- metadata: {}
-  model_id: nvidia/vila
   provider_id: nvidia
-  provider_model_id: nvidia/vila
   model_type: llm
+  use_provider_model_id_as_id: false
+- metadata: {}
+  provider_model_id: nvidia/vila
+  provider_id: nvidia
+  model_type: llm
+  use_provider_model_id_as_id: false
 - metadata:
     embedding_dimension: 2048
     context_length: 8192
-  model_id: nvidia/llama-3.2-nv-embedqa-1b-v2
-  provider_id: nvidia
   provider_model_id: nvidia/llama-3.2-nv-embedqa-1b-v2
+  provider_id: nvidia
   model_type: embedding
+  use_provider_model_id_as_id: false
 - metadata:
     embedding_dimension: 1024
     context_length: 512
-  model_id: nvidia/nv-embedqa-e5-v5
-  provider_id: nvidia
   provider_model_id: nvidia/nv-embedqa-e5-v5
+  provider_id: nvidia
   model_type: embedding
+  use_provider_model_id_as_id: false
 - metadata:
     embedding_dimension: 4096
     context_length: 512
-  model_id: nvidia/nv-embedqa-mistral-7b-v2
-  provider_id: nvidia
   provider_model_id: nvidia/nv-embedqa-mistral-7b-v2
+  provider_id: nvidia
   model_type: embedding
+  use_provider_model_id_as_id: false
 - metadata:
     embedding_dimension: 1024
     context_length: 512
-  model_id: snowflake/arctic-embed-l
-  provider_id: nvidia
   provider_model_id: snowflake/arctic-embed-l
+  provider_id: nvidia
   model_type: embedding
+  use_provider_model_id_as_id: false
 shields: []
 vector_dbs: []
 datasets: []

llama_stack/distributions/open-benchmark/run.yaml

@@ -136,30 +136,32 @@ inference_store:
   db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/open-benchmark}/inference_store.db
 models:
 - metadata: {}
-  model_id: gpt-4o
-  provider_id: openai
   provider_model_id: gpt-4o
+  provider_id: openai
   model_type: llm
+  use_provider_model_id_as_id: false
 - metadata: {}
-  model_id: claude-3-5-sonnet-latest
-  provider_id: anthropic
   provider_model_id: claude-3-5-sonnet-latest
+  provider_id: anthropic
   model_type: llm
+  use_provider_model_id_as_id: false
 - metadata: {}
-  model_id: gemini/gemini-1.5-flash
-  provider_id: gemini
   provider_model_id: gemini/gemini-1.5-flash
+  provider_id: gemini
   model_type: llm
+  use_provider_model_id_as_id: false
 - metadata: {}
-  model_id: meta-llama/Llama-3.3-70B-Instruct
-  provider_id: groq
   provider_model_id: groq/llama-3.3-70b-versatile
+  provider_id: groq
   model_type: llm
+  model_id: meta-llama/Llama-3.3-70B-Instruct
+  use_provider_model_id_as_id: false
 - metadata: {}
-  model_id: meta-llama/Llama-3.1-405B-Instruct
-  provider_id: together
   provider_model_id: meta-llama/Meta-Llama-3.1-405B-Instruct-Turbo
+  provider_id: together
   model_type: llm
+  model_id: meta-llama/Llama-3.1-405B-Instruct
+  use_provider_model_id_as_id: false
 shields:
 - shield_id: meta-llama/Llama-Guard-3-8B
 vector_dbs: []

llama_stack/distributions/postgres-demo/postgres_demo.py

@@ -75,7 +75,7 @@ def get_distribution_template() -> DistributionTemplate:
 
     default_models = [
         ModelInput(
-            model_id="${env.INFERENCE_MODEL}",
+            provider_model_id="${env.INFERENCE_MODEL}",
             provider_id="vllm-inference",
         )
     ]
@@ -85,7 +85,7 @@ def get_distribution_template() -> DistributionTemplate:
         config=SentenceTransformersInferenceConfig.sample_run_config(),
     )
     embedding_model = ModelInput(
-        model_id="all-MiniLM-L6-v2",
+        provider_model_id="all-MiniLM-L6-v2",
         provider_id=embedding_provider.provider_id,
         model_type=ModelType.embedding,
         metadata={

llama_stack/distributions/postgres-demo/run.yaml

@@ -88,14 +88,16 @@ inference_store:
   password: ${env.POSTGRES_PASSWORD:=llamastack}
 models:
 - metadata: {}
-  model_id: ${env.INFERENCE_MODEL}
+  provider_model_id: ${env.INFERENCE_MODEL}
   provider_id: vllm-inference
   model_type: llm
+  use_provider_model_id_as_id: false
 - metadata:
     embedding_dimension: 384
-  model_id: all-MiniLM-L6-v2
+  provider_model_id: all-MiniLM-L6-v2
   provider_id: sentence-transformers
   model_type: embedding
+  use_provider_model_id_as_id: false
 shields:
 - shield_id: meta-llama/Llama-Guard-3-8B
 vector_dbs: []

llama_stack/distributions/template.py

@@ -114,7 +114,7 @@ def get_model_registry(
                 identifier = f"{provider_id}/{model_id}" if ids_conflict and provider_id not in model_id else model_id
                 models.append(
                     ModelInput(
-                        model_id=identifier,
+                        model_id=identifier if identifier != entry.provider_model_id else None,
                         provider_model_id=entry.provider_model_id,
                         provider_id=provider_id,
                         model_type=entry.model_type,

llama_stack/distributions/watsonx/watsonx.py

@@ -73,7 +73,7 @@ def get_distribution_template(name: str = "watsonx") -> DistributionTemplate:
     ]
 
     embedding_model = ModelInput(
-        model_id="all-MiniLM-L6-v2",
+        provider_model_id="all-MiniLM-L6-v2",
         provider_id="sentence-transformers",
         model_type=ModelType.embedding,
         metadata={

llama_stack/log.py

@@ -9,11 +9,19 @@ import os
 import re
 from logging.config import dictConfig  # allow-direct-logging
 
+from pydantic import BaseModel, Field
 from rich.console import Console
 from rich.errors import MarkupError
 from rich.logging import RichHandler
 
-from llama_stack.core.datatypes import LoggingConfig
+
+class LoggingConfig(BaseModel):
+    category_levels: dict[str, str] = Field(
+        default_factory=dict,
+        description="""
+ Dictionary of different logging configurations for different portions (ex: core, server) of llama stack""",
+    )
+
 
 # Default log level
 DEFAULT_LOG_LEVEL = logging.INFO

tests/unit/distribution/routers/test_routing_tables.py

@@ -645,3 +645,88 @@ async def test_models_source_interaction_cleanup_provider_models(cached_disk_dis
 
     # Cleanup
     await table.shutdown()
+
+
+async def test_models_register_with_use_provider_model_id_as_id(cached_disk_dist_registry):
+    """Test register_model with the new use_provider_model_id_as_id parameter."""
+    table = ModelsRoutingTable({"test_provider": InferenceImpl()}, cached_disk_dist_registry, {})
+    await table.initialize()
+
+    # Register model using use_provider_model_id_as_id parameter
+    await table.register_model(
+        provider_model_id="actual-provider-model", provider_id="test_provider", use_provider_model_id_as_id=True
+    )
+
+    # Verify the model was registered with provider_model_id as identifier
+    models = await table.list_models()
+    assert len(models.data) == 1
+    model = models.data[0]
+    assert model.identifier == "actual-provider-model"
+    assert model.provider_resource_id == "actual-provider-model"
+    assert model.provider_id == "test_provider"
+
+    # Test lookup by provider_model_id works
+    retrieved_model = await table.get_model("actual-provider-model")
+    assert retrieved_model.identifier == "actual-provider-model"
+    assert retrieved_model.provider_resource_id == "actual-provider-model"
+
+    # Cleanup
+    await table.shutdown()
+
+
+async def test_models_register_provider_model_id_only(cached_disk_dist_registry):
+    """Test register_model with only provider_model_id (new recommended usage)."""
+    table = ModelsRoutingTable({"test_provider": InferenceImpl()}, cached_disk_dist_registry, {})
+    await table.initialize()
+
+    # Register model using only provider_model_id
+    await table.register_model(provider_model_id="llama-3.1-8b", provider_id="test_provider", model_type=ModelType.llm)
+
+    # Verify the model was registered with namespaced identifier
+    models = await table.list_models()
+    assert len(models.data) == 1
+    model = models.data[0]
+    assert model.identifier == "test_provider/llama-3.1-8b"
+    assert model.provider_resource_id == "llama-3.1-8b"
+    assert model.provider_id == "test_provider"
+
+    # Test lookup works
+    retrieved_model = await table.get_model("test_provider/llama-3.1-8b")
+    assert retrieved_model.identifier == "test_provider/llama-3.1-8b"
+
+    # Cleanup
+    await table.shutdown()
+
+
+async def test_models_register_validation_errors(cached_disk_dist_registry):
+    """Test register_model validation errors."""
+    table = ModelsRoutingTable({"test_provider": InferenceImpl()}, cached_disk_dist_registry, {})
+    await table.initialize()
+
+    # Test error when neither model_id nor provider_model_id is provided
+    with pytest.raises(ValueError, match="provider_model_id must be provided"):
+        await table.register_model(provider_id="test_provider")
+
+    # Cleanup
+    await table.shutdown()
+
+
+async def test_models_register_backward_compatibility_warning(cached_disk_dist_registry):
+    """Test that register_model warns when model_id equals provider_model_id."""
+    from unittest.mock import patch
+
+    table = ModelsRoutingTable({"test_provider": InferenceImpl()}, cached_disk_dist_registry, {})
+    await table.initialize()
+
+    # Test warning is logged when model_id == provider_model_id
+    with patch("llama_stack.core.routing_tables.models.logger") as mock_logger:
+        await table.register_model(model_id="same-model", provider_model_id="same-model", provider_id="test_provider")
+
+        # Verify warning was called
+        mock_logger.warning.assert_called_once()
+        warning_msg = mock_logger.warning.call_args[0][0]
+        assert "model_id` is now optional" in warning_msg
+        assert "provider_model_id='same-model'" in warning_msg
+
+    # Cleanup
+    await table.shutdown()