Add fixes

pyproject.toml

@@ -24,7 +24,6 @@ dependencies = [
     "hypercorn>=0.18.0",
     "openai-harmony>=0.0.8",
     "httpx>=0.28.1",
-    "tomlkit>=0.14.0",
 ]
 
 [project.scripts]

src/exo/master/api.py

@@ -19,11 +19,8 @@ from exo.master.placement import place_instance as get_instance_placements
 from exo.shared.apply import apply
 from exo.shared.election import ElectionMessage
 from exo.shared.logging import InterceptLogger
-from exo.shared.models.model_cards import (
-    MODEL_CARDS,
-    ModelCard,
-    ModelId,
-)
+from exo.shared.models.model_cards import MODEL_CARDS, ModelCard, ModelId
+from exo.shared.models.model_meta import get_model_card
 from exo.shared.types.api import (
     BenchChatCompletionResponse,
     BenchChatCompletionTaskParams,
@@ -44,7 +41,7 @@ from exo.shared.types.api import (
     PlacementPreviewResponse,
     StreamingChoiceResponse,
 )
-from exo.shared.types.chunks import TokenChunk, ToolCallChunk
+from exo.shared.types.chunks import TokenChunk
 from exo.shared.types.commands import (
     ChatCompletion,
     Command,
@@ -73,7 +70,7 @@ from exo.utils.event_buffer import OrderedBuffer
 
 
 def chunk_to_response(
-    chunk: TokenChunk | ToolCallChunk, command_id: CommandId
+    chunk: TokenChunk, command_id: CommandId
 ) -> ChatCompletionResponse:
     return ChatCompletionResponse(
         id=command_id,
@@ -85,25 +82,16 @@ def chunk_to_response(
                 delta=ChatCompletionMessage(role="assistant", content=chunk.text),
                 finish_reason=chunk.finish_reason,
             )
-            if isinstance(chunk, TokenChunk)
-            else StreamingChoiceResponse(
-                index=0,
-                delta=ChatCompletionMessage(
-                    role="assistant",
-                    tool_calls=[tool.model_dump() for tool in chunk.tool_calls],
-                ),
-                finish_reason="tool_calls",
-            )
         ],
     )
 
 
-async def resolve_model_card(model_id: ModelId) -> ModelCard:
+async def resolve_model_card(model_id: str) -> ModelCard:
     if model_id in MODEL_CARDS:
         model_card = MODEL_CARDS[model_id]
         return model_card
     else:
-        return await ModelCard.from_hf(model_id)
+        return await get_model_card(model_id)
 
 
 class API:
@@ -147,9 +135,7 @@ class API:
             name="dashboard",
         )
 
-        self._chat_completion_queues: dict[
-            CommandId, Sender[TokenChunk | ToolCallChunk]
-        ] = {}
+        self._chat_completion_queues: dict[CommandId, Sender[TokenChunk]] = {}
         self._tg: TaskGroup | None = None
 
     def reset(self, new_session_id: SessionId, result_clock: int):
@@ -250,7 +236,7 @@ class API:
 
     async def get_placement(
         self,
-        model_id: ModelId,
+        model_id: str,
         sharding: Sharding = Sharding.Pipeline,
         instance_meta: InstanceMeta = InstanceMeta.MlxRing,
         min_nodes: int = 1,
@@ -415,21 +401,16 @@ class API:
 
     async def _chat_chunk_stream(
         self, command_id: CommandId
-    ) -> AsyncGenerator[TokenChunk | ToolCallChunk, None]:
+    ) -> AsyncGenerator[TokenChunk, None]:
         """Yield `TokenChunk`s for a given command until completion."""
 
         try:
-            self._chat_completion_queues[command_id], recv = channel[
-                TokenChunk | ToolCallChunk
-            ]()
+            self._chat_completion_queues[command_id], recv = channel[TokenChunk]()
 
             with recv as token_chunks:
                 async for chunk in token_chunks:
                     yield chunk
-                    if (
-                        isinstance(chunk, TokenChunk)
-                        and chunk.finish_reason is not None
-                    ):
+                    if chunk.finish_reason is not None:
                         break
 
         except anyio.get_cancelled_exc_class():
@@ -451,7 +432,7 @@ class API:
         """Generate chat completion stream as JSON strings."""
 
         async for chunk in self._chat_chunk_stream(command_id):
-            if isinstance(chunk, TokenChunk) and chunk.finish_reason == "error":
+            if chunk.finish_reason == "error":
                 error_response = ErrorResponse(
                     error=ErrorInfo(
                         message=chunk.error_message or "Internal server error",
@@ -470,7 +451,7 @@ class API:
 
             yield f"data: {chunk_response.model_dump_json()}\n\n"
 
-            if isinstance(chunk, ToolCallChunk) or chunk.finish_reason is not None:
+            if chunk.finish_reason is not None:
                 yield "data: [DONE]\n\n"
 
     async def _collect_chat_completion(
@@ -483,24 +464,6 @@ class API:
         finish_reason: FinishReason | None = None
 
         async for chunk in self._chat_chunk_stream(command_id):
-            if isinstance(chunk, ToolCallChunk):
-                finish_reason = "tool_calls"
-                return ChatCompletionResponse(
-                    id=command_id,
-                    created=int(time.time()),
-                    model=model or chunk.model,
-                    choices=[
-                        ChatCompletionChoice(
-                            index=0,
-                            message=ChatCompletionMessage(
-                                role="assistant",
-                                tool_calls=[
-                                    tool.model_dump() for tool in chunk.tool_calls
-                                ],
-                            ),
-                        )
-                    ],
-                )
             if chunk.finish_reason == "error":
                 raise HTTPException(
                     status_code=500,
@@ -544,11 +507,6 @@ class API:
         stats: GenerationStats | None = None
 
         async for chunk in self._chat_chunk_stream(command_id):
-            if isinstance(chunk, ToolCallChunk):
-                raise HTTPException(
-                    status_code=500,
-                    detail="Tool call in bench",
-                )
             if chunk.finish_reason == "error":
                 raise HTTPException(
                     status_code=500,
@@ -593,7 +551,7 @@ class API:
         self, payload: ChatCompletionTaskParams
     ) -> ChatCompletionResponse | StreamingResponse:
         """Handle chat completions, supporting both streaming and non-streaming responses."""
-        model_card = await resolve_model_card(ModelId(payload.model))
+        model_card = await resolve_model_card(payload.model)
         payload.model = model_card.model_id
 
         if not any(
@@ -620,7 +578,7 @@ class API:
     async def bench_chat_completions(
         self, payload: BenchChatCompletionTaskParams
     ) -> BenchChatCompletionResponse:
-        model_card = await resolve_model_card(ModelId(payload.model))
+        model_card = await resolve_model_card(payload.model)
         payload.model = model_card.model_id
 
         if not any(
@@ -699,7 +657,7 @@ class API:
                     self._event_log.append(event)
                     self.state = apply(self.state, IndexedEvent(event=event, idx=idx))
                     if isinstance(event, ChunkGenerated):
-                        assert isinstance(event.chunk, (TokenChunk, ToolCallChunk))
+                        assert isinstance(event.chunk, TokenChunk)
                         queue = self._chat_completion_queues.get(event.command_id)
                         if queue is not None:
                             try:

src/exo/shared/models/model_cards.py

@@ -1,18 +1,16 @@
-from typing import Annotated
+from pydantic import PositiveInt
 
-import aiofiles
-import aiofiles.os as aios
-import tomlkit
-from anyio import Path, open_file
-from huggingface_hub import model_info
-from loguru import logger
-from pydantic import BaseModel, Field, PositiveInt
-
-from exo.shared.types.common import ModelId
+from exo.shared.types.common import Id
 from exo.shared.types.memory import Memory
 from exo.utils.pydantic_ext import CamelCaseModel
 
-_card_cache: dict[str, "ModelCard"] = {}
+
+class ModelId(Id):
+    def normalize(self) -> str:
+        return self.replace("/", "--")
+
+    def short(self) -> str:
+        return self.split("/")[-1]
 
 
 class ModelCard(CamelCaseModel):
@@ -22,43 +20,6 @@ class ModelCard(CamelCaseModel):
     hidden_size: PositiveInt
     supports_tensor: bool
 
-    async def save(self, path: Path) -> None:
-        async with await open_file(path, "w") as f:
-            py = self.model_dump()
-            data = tomlkit.dumps(py)  # pyright: ignore[reportUnknownMemberType]
-            await f.write(data)
-
-    @staticmethod
-    async def load_from_path(path: Path) -> "ModelCard":
-        async with await open_file(path, "r") as f:
-            py = tomlkit.loads(await f.read())
-            return ModelCard.model_validate(py)
-
-    @staticmethod
-    async def load(model_id: ModelId) -> "ModelCard":
-        if model_id in MODEL_CARDS:
-            return MODEL_CARDS[model_id]
-        return await ModelCard.from_hf(model_id)
-
-    @staticmethod
-    async def from_hf(model_id: ModelId) -> "ModelCard":
-        """Fetches storage size and number of layers for a Hugging Face model, returns Pydantic ModelMeta."""
-        if (mc := _card_cache.get(model_id)) is not None:
-            return mc
-        config_data = await get_config_data(model_id)
-        num_layers = config_data.layer_count
-        mem_size_bytes = await get_safetensors_size(model_id)
-
-        mc = ModelCard(
-            model_id=ModelId(model_id),
-            storage_size=mem_size_bytes,
-            n_layers=num_layers,
-            hidden_size=config_data.hidden_size or 0,
-            supports_tensor=config_data.supports_tensor,
-        )
-        _card_cache[model_id] = mc
-        return mc
-
 
 MODEL_CARDS: dict[str, ModelCard] = {
     # deepseek v3
@@ -347,99 +308,3 @@ MODEL_CARDS: dict[str, ModelCard] = {
         supports_tensor=True,
     ),
 }
-
-from exo.worker.download.download_utils import (  # noqa: E402
-    ModelSafetensorsIndex,
-    download_file_with_retry,
-    ensure_models_dir,
-)
-
-
-class ConfigData(BaseModel):
-    model_config = {"extra": "ignore"}  # Allow unknown fields
-
-    # Common field names for number of layers across different architectures
-    num_hidden_layers: Annotated[int, Field(ge=0)] | None = None
-    num_layers: Annotated[int, Field(ge=0)] | None = None
-    n_layer: Annotated[int, Field(ge=0)] | None = None
-    n_layers: Annotated[int, Field(ge=0)] | None = None  # Sometimes used
-    num_decoder_layers: Annotated[int, Field(ge=0)] | None = None  # Transformer models
-    decoder_layers: Annotated[int, Field(ge=0)] | None = None  # Some architectures
-    hidden_size: Annotated[int, Field(ge=0)] | None = None
-    architectures: list[str] | None = None
-
-    @property
-    def supports_tensor(self) -> bool:
-        return self.architectures in [
-            ["Glm4MoeLiteForCausalLM"],
-            ["DeepseekV32ForCausalLM"],
-            ["DeepseekV3ForCausalLM"],
-            ["Qwen3NextForCausalLM"],
-            ["Qwen3MoeForCausalLM"],
-            ["MiniMaxM2ForCausalLM"],
-            ["LlamaForCausalLM"],
-            ["GptOssForCausalLM"],
-        ]
-
-    @property
-    def layer_count(self) -> int:
-        # Check common field names for layer count
-        layer_fields = [
-            self.num_hidden_layers,
-            self.num_layers,
-            self.n_layer,
-            self.n_layers,
-            self.num_decoder_layers,
-            self.decoder_layers,
-        ]
-
-        for layer_count in layer_fields:
-            if layer_count is not None:
-                return layer_count
-
-        raise ValueError(
-            f"No layer count found in config.json: {self.model_dump_json()}"
-        )
-
-
-async def get_config_data(model_id: ModelId) -> ConfigData:
-    """Downloads and parses config.json for a model."""
-    target_dir = (await ensure_models_dir()) / model_id.normalize()
-    await aios.makedirs(target_dir, exist_ok=True)
-    config_path = await download_file_with_retry(
-        model_id,
-        "main",
-        "config.json",
-        target_dir,
-        lambda curr_bytes, total_bytes, is_renamed: logger.info(
-            f"Downloading config.json for {model_id}: {curr_bytes}/{total_bytes} ({is_renamed=})"
-        ),
-    )
-    async with aiofiles.open(config_path, "r") as f:
-        return ConfigData.model_validate_json(await f.read())
-
-
-async def get_safetensors_size(model_id: ModelId) -> Memory:
-    """Gets model size from safetensors index or falls back to HF API."""
-    target_dir = (await ensure_models_dir()) / model_id.normalize()
-    await aios.makedirs(target_dir, exist_ok=True)
-    index_path = await download_file_with_retry(
-        model_id,
-        "main",
-        "model.safetensors.index.json",
-        target_dir,
-        lambda curr_bytes, total_bytes, is_renamed: logger.info(
-            f"Downloading model.safetensors.index.json for {model_id}: {curr_bytes}/{total_bytes} ({is_renamed=})"
-        ),
-    )
-    async with aiofiles.open(index_path, "r") as f:
-        index_data = ModelSafetensorsIndex.model_validate_json(await f.read())
-
-    metadata = index_data.metadata
-    if metadata is not None:
-        return Memory.from_bytes(metadata.total_size)
-
-    info = model_info(model_id)
-    if info.safetensors is None:
-        raise ValueError(f"No safetensors info found for {model_id}")
-    return Memory.from_bytes(info.safetensors.total)

src/exo/shared/models/model_meta.py

@@ -0,0 +1,122 @@
+from typing import Annotated
+
+import aiofiles
+import aiofiles.os as aios
+from huggingface_hub import model_info
+from loguru import logger
+from pydantic import BaseModel, Field
+
+from exo.shared.models.model_cards import MODEL_CARDS, ModelCard, ModelId
+from exo.shared.types.memory import Memory
+from exo.worker.download.download_utils import (
+    ModelSafetensorsIndex,
+    download_file_with_retry,
+    ensure_models_dir,
+)
+
+
+class ConfigData(BaseModel):
+    model_config = {"extra": "ignore"}  # Allow unknown fields
+
+    # Common field names for number of layers across different architectures
+    num_hidden_layers: Annotated[int, Field(ge=0)] | None = None
+    num_layers: Annotated[int, Field(ge=0)] | None = None
+    n_layer: Annotated[int, Field(ge=0)] | None = None
+    n_layers: Annotated[int, Field(ge=0)] | None = None  # Sometimes used
+    num_decoder_layers: Annotated[int, Field(ge=0)] | None = None  # Transformer models
+    decoder_layers: Annotated[int, Field(ge=0)] | None = None  # Some architectures
+    hidden_size: Annotated[int, Field(ge=0)] | None = None
+
+    @property
+    def layer_count(self) -> int:
+        # Check common field names for layer count
+        layer_fields = [
+            self.num_hidden_layers,
+            self.num_layers,
+            self.n_layer,
+            self.n_layers,
+            self.num_decoder_layers,
+            self.decoder_layers,
+        ]
+
+        for layer_count in layer_fields:
+            if layer_count is not None:
+                return layer_count
+
+        raise ValueError(
+            f"No layer count found in config.json: {self.model_dump_json()}"
+        )
+
+
+async def get_config_data(model_id: str) -> ConfigData:
+    """Downloads and parses config.json for a model."""
+    target_dir = (await ensure_models_dir()) / str(model_id).replace("/", "--")
+    await aios.makedirs(target_dir, exist_ok=True)
+    config_path = await download_file_with_retry(
+        model_id,
+        "main",
+        "config.json",
+        target_dir,
+        lambda curr_bytes, total_bytes, is_renamed: logger.info(
+            f"Downloading config.json for {model_id}: {curr_bytes}/{total_bytes} ({is_renamed=})"
+        ),
+    )
+    async with aiofiles.open(config_path, "r") as f:
+        return ConfigData.model_validate_json(await f.read())
+
+
+async def get_safetensors_size(model_id: str) -> Memory:
+    """Gets model size from safetensors index or falls back to HF API."""
+    target_dir = (await ensure_models_dir()) / str(model_id).replace("/", "--")
+    await aios.makedirs(target_dir, exist_ok=True)
+    index_path = await download_file_with_retry(
+        model_id,
+        "main",
+        "model.safetensors.index.json",
+        target_dir,
+        lambda curr_bytes, total_bytes, is_renamed: logger.info(
+            f"Downloading model.safetensors.index.json for {model_id}: {curr_bytes}/{total_bytes} ({is_renamed=})"
+        ),
+    )
+    async with aiofiles.open(index_path, "r") as f:
+        index_data = ModelSafetensorsIndex.model_validate_json(await f.read())
+
+    metadata = index_data.metadata
+    if metadata is not None:
+        return Memory.from_bytes(metadata.total_size)
+
+    info = model_info(model_id)
+    if info.safetensors is None:
+        raise ValueError(f"No safetensors info found for {model_id}")
+    return Memory.from_bytes(info.safetensors.total)
+
+
+_model_card_cache: dict[str, ModelCard] = {}
+
+
+async def get_model_card(model_id: str) -> ModelCard:
+    if model_id in _model_card_cache:
+        return _model_card_cache[model_id]
+    model_card = await _get_model_card(model_id)
+    _model_card_cache[model_id] = model_card
+    return model_card
+
+
+async def _get_model_card(model_id: str) -> ModelCard:
+    """Fetches storage size and number of layers for a Hugging Face model, returns Pydantic ModelMeta."""
+    config_data = await get_config_data(model_id)
+    num_layers = config_data.layer_count
+    mem_size_bytes = await get_safetensors_size(model_id)
+    model_card = next(
+        (card for card in MODEL_CARDS.values() if card.model_id == ModelId(model_id)),
+        None,
+    )
+
+    return ModelCard(
+        model_id=ModelId(model_id),
+        storage_size=mem_size_bytes,
+        n_layers=num_layers,
+        hidden_size=config_data.hidden_size or 0,
+        # TODO: all custom models currently do not support tensor. We could add a dynamic test for this?
+        supports_tensor=model_card.supports_tensor if model_card is not None else False,
+    )

src/exo/shared/types/api.py

@@ -168,7 +168,7 @@ class BenchChatCompletionTaskParams(ChatCompletionTaskParams):
 
 
 class PlaceInstanceParams(BaseModel):
-    model_id: ModelId
+    model_id: str
     sharding: Sharding = Sharding.Pipeline
     instance_meta: InstanceMeta = InstanceMeta.MlxRing
     min_nodes: int = 1

src/exo/shared/types/chunks.py

@@ -5,7 +5,6 @@ from exo.shared.types.api import GenerationStats
 from exo.utils.pydantic_ext import TaggedModel
 
 from .api import FinishReason
-from .worker.runner_response import ToolCallItem
 
 
 class ChunkType(str, Enum):
@@ -26,12 +25,8 @@ class TokenChunk(BaseChunk):
     error_message: str | None = None
 
 
-class ToolCallChunk(BaseChunk):
-    tool_calls: list[ToolCallItem]
-
-
 class ImageChunk(BaseChunk):
     data: bytes
 
 
-GenerationChunk = TokenChunk | ImageChunk | ToolCallChunk
+GenerationChunk = TokenChunk | ImageChunk

src/exo/shared/types/common.py

@@ -25,14 +25,6 @@ class NodeId(Id):
     pass
 
 
-class ModelId(Id):
-    def normalize(self) -> str:
-        return self.replace("/", "--")
-
-    def short(self) -> str:
-        return self.split("/")[-1]
-
-
 class SessionId(CamelCaseModel):
     master_node_id: NodeId
     election_clock: int

src/exo/shared/types/worker/downloads.py

@@ -1,8 +1,3 @@
-from datetime import timedelta
-from typing import Literal
-
-from pydantic import BaseModel, ConfigDict, Field, PositiveInt
-
 from exo.shared.types.common import NodeId
 from exo.shared.types.memory import Memory
 from exo.shared.types.worker.shards import ShardMetadata
@@ -47,50 +42,3 @@ class DownloadOngoing(BaseDownloadProgress):
 DownloadProgress = (
     DownloadPending | DownloadCompleted | DownloadFailed | DownloadOngoing
 )
-
-
-class ModelSafetensorsIndexMetadata(BaseModel):
-    total_size: PositiveInt
-
-
-class ModelSafetensorsIndex(BaseModel):
-    metadata: ModelSafetensorsIndexMetadata | None
-    weight_map: dict[str, str]
-
-
-class FileListEntry(BaseModel):
-    type: Literal["file", "directory"]
-    path: str
-    size: int | None = None
-
-
-class RepoFileDownloadProgress(BaseModel):
-    repo_id: str
-    repo_revision: str
-    file_path: str
-    downloaded: Memory
-    downloaded_this_session: Memory
-    total: Memory
-    speed: float
-    eta: timedelta
-    status: Literal["not_started", "in_progress", "complete"]
-    start_time: float
-
-    model_config = ConfigDict(frozen=True)
-
-
-class RepoDownloadProgress(BaseModel):
-    repo_id: str
-    repo_revision: str
-    shard: ShardMetadata
-    completed_files: int
-    total_files: int
-    downloaded_bytes: Memory
-    downloaded_bytes_this_session: Memory
-    total_bytes: Memory
-    overall_speed: float
-    overall_eta: timedelta
-    status: Literal["not_started", "in_progress", "complete"]
-    file_progress: dict[str, RepoFileDownloadProgress] = Field(default_factory=dict)
-
-    model_config = ConfigDict(frozen=True)

src/exo/shared/types/worker/runner_response.py

@@ -1,5 +1,5 @@
 from exo.shared.types.api import FinishReason, GenerationStats
-from exo.utils.pydantic_ext import CamelCaseModel, TaggedModel
+from exo.utils.pydantic_ext import TaggedModel
 
 
 class BaseRunnerResponse(TaggedModel):
@@ -10,11 +10,6 @@ class TokenizedResponse(BaseRunnerResponse):
     prompt_tokens: int
 
 
-class ToolCallItem(CamelCaseModel):
-    arguments: str
-    name: str
-
-
 class GenerationResponse(BaseRunnerResponse):
     text: str
     token: int
@@ -23,9 +18,5 @@ class GenerationResponse(BaseRunnerResponse):
     stats: GenerationStats | None = None
 
 
-class ToolCallResponse(BaseRunnerResponse):
-    tool_calls: list[ToolCallItem]
-
-
 class FinishedResponse(BaseRunnerResponse):
     pass

src/exo/worker/download/download_utils.py

@@ -17,20 +17,17 @@ import aiohttp
 import certifi
 from loguru import logger
 from pydantic import (
+    BaseModel,
+    ConfigDict,
     DirectoryPath,
+    Field,
+    PositiveInt,
     TypeAdapter,
 )
 
 from exo.shared.constants import EXO_MODELS_DIR
-from exo.shared.types.common import ModelId
 from exo.shared.types.memory import Memory
-from exo.shared.types.worker.downloads import (
-    DownloadProgressData,
-    FileListEntry,
-    ModelSafetensorsIndex,
-    RepoDownloadProgress,
-    RepoFileDownloadProgress,
-)
+from exo.shared.types.worker.downloads import DownloadProgressData
 from exo.shared.types.worker.shards import ShardMetadata
 from exo.worker.download.huggingface_utils import (
     filter_repo_objects,
@@ -40,6 +37,53 @@ from exo.worker.download.huggingface_utils import (
 )
 
 
+class ModelSafetensorsIndexMetadata(BaseModel):
+    total_size: PositiveInt
+
+
+class ModelSafetensorsIndex(BaseModel):
+    metadata: ModelSafetensorsIndexMetadata | None
+    weight_map: dict[str, str]
+
+
+class FileListEntry(BaseModel):
+    type: Literal["file", "directory"]
+    path: str
+    size: int | None = None
+
+
+class RepoFileDownloadProgress(BaseModel):
+    repo_id: str
+    repo_revision: str
+    file_path: str
+    downloaded: Memory
+    downloaded_this_session: Memory
+    total: Memory
+    speed: float
+    eta: timedelta
+    status: Literal["not_started", "in_progress", "complete"]
+    start_time: float
+
+    model_config = ConfigDict(frozen=True)
+
+
+class RepoDownloadProgress(BaseModel):
+    repo_id: str
+    repo_revision: str
+    shard: ShardMetadata
+    completed_files: int
+    total_files: int
+    downloaded_bytes: Memory
+    downloaded_bytes_this_session: Memory
+    total_bytes: Memory
+    overall_speed: float
+    overall_eta: timedelta
+    status: Literal["not_started", "in_progress", "complete"]
+    file_progress: dict[str, RepoFileDownloadProgress] = Field(default_factory=dict)
+
+    model_config = ConfigDict(frozen=True)
+
+
 def trim_etag(etag: str) -> str:
     if (etag[0] == '"' and etag[-1] == '"') or (etag[0] == "'" and etag[-1] == "'"):
         return etag[1:-1]
@@ -81,12 +125,12 @@ def map_repo_download_progress_to_download_progress_data(
     )
 
 
-def build_model_path(model_id: ModelId) -> DirectoryPath:
-    return EXO_MODELS_DIR / model_id.normalize()
+def build_model_path(model_id: str) -> DirectoryPath:
+    return EXO_MODELS_DIR / model_id.replace("/", "--")
 
 
-async def resolve_model_path_for_repo(model_id: ModelId) -> Path:
-    return (await ensure_models_dir()) / model_id.normalize()
+async def resolve_model_path_for_repo(repo_id: str) -> Path:
+    return (await ensure_models_dir()) / repo_id.replace("/", "--")
 
 
 async def ensure_models_dir() -> Path:
@@ -94,8 +138,8 @@ async def ensure_models_dir() -> Path:
     return EXO_MODELS_DIR
 
 
-async def delete_model(model_id: ModelId) -> bool:
-    model_dir = await ensure_models_dir() / model_id.normalize()
+async def delete_model(repo_id: str) -> bool:
+    model_dir = await ensure_models_dir() / repo_id.replace("/", "--")
     if not await aios.path.exists(model_dir):
         return False
     await asyncio.to_thread(shutil.rmtree, model_dir, ignore_errors=False)
@@ -120,17 +164,19 @@ async def seed_models(seed_dir: str | Path):
 
 
 async def fetch_file_list_with_cache(
-    model_id: ModelId, revision: str = "main", recursive: bool = False
+    repo_id: str, revision: str = "main", recursive: bool = False
 ) -> list[FileListEntry]:
-    target_dir = (await ensure_models_dir()) / "caches" / model_id.normalize()
+    target_dir = (
+        (await ensure_models_dir()) / "caches" / str(repo_id).replace("/", "--")
+    )
     await aios.makedirs(target_dir, exist_ok=True)
-    cache_file = target_dir / f"{model_id.normalize()}--{revision}--file_list.json"
+    cache_file = (
+        target_dir / f"{repo_id.replace('/', '--')}--{revision}--file_list.json"
+    )
     if await aios.path.exists(cache_file):
         async with aiofiles.open(cache_file, "r") as f:
             return TypeAdapter(list[FileListEntry]).validate_json(await f.read())
-    file_list = await fetch_file_list_with_retry(
-        model_id, revision, recursive=recursive
-    )
+    file_list = await fetch_file_list_with_retry(repo_id, revision, recursive=recursive)
     await aios.makedirs(cache_file.parent, exist_ok=True)
     async with aiofiles.open(cache_file, "w") as f:
         await f.write(TypeAdapter(list[FileListEntry]).dump_json(file_list).decode())
@@ -138,25 +184,25 @@ async def fetch_file_list_with_cache(
 
 
 async def fetch_file_list_with_retry(
-    model_id: ModelId, revision: str = "main", path: str = "", recursive: bool = False
+    repo_id: str, revision: str = "main", path: str = "", recursive: bool = False
 ) -> list[FileListEntry]:
     n_attempts = 30
     for attempt in range(n_attempts):
         try:
-            return await _fetch_file_list(model_id, revision, path, recursive)
+            return await _fetch_file_list(repo_id, revision, path, recursive)
         except Exception as e:
             if attempt == n_attempts - 1:
                 raise e
             await asyncio.sleep(min(8, 0.1 * float(2.0 ** int(attempt))))
     raise Exception(
-        f"Failed to fetch file list for {model_id=} {revision=} {path=} {recursive=}"
+        f"Failed to fetch file list for {repo_id=} {revision=} {path=} {recursive=}"
     )
 
 
 async def _fetch_file_list(
-    model_id: ModelId, revision: str = "main", path: str = "", recursive: bool = False
+    repo_id: str, revision: str = "main", path: str = "", recursive: bool = False
 ) -> list[FileListEntry]:
-    api_url = f"{get_hf_endpoint()}/api/models/{model_id}/tree/{revision}"
+    api_url = f"{get_hf_endpoint()}/api/models/{repo_id}/tree/{revision}"
     url = f"{api_url}/{path}" if path else api_url
 
     headers = await get_download_headers()
@@ -173,7 +219,7 @@ async def _fetch_file_list(
                     files.append(FileListEntry.model_validate(item))
                 elif item.type == "directory" and recursive:
                     subfiles = await _fetch_file_list(
-                        model_id, revision, item.path, recursive
+                        repo_id, revision, item.path, recursive
                     )
                     files.extend(subfiles)
             return files
@@ -230,10 +276,10 @@ async def calc_hash(path: Path, hash_type: Literal["sha1", "sha256"] = "sha1") -
 
 
 async def file_meta(
-    model_id: ModelId, revision: str, path: str, redirected_location: str | None = None
+    repo_id: str, revision: str, path: str, redirected_location: str | None = None
 ) -> tuple[int, str]:
     url = (
-        urljoin(f"{get_hf_endpoint()}/{model_id}/resolve/{revision}/", path)
+        urljoin(f"{get_hf_endpoint()}/{repo_id}/resolve/{revision}/", path)
         if redirected_location is None
         else f"{get_hf_endpoint()}{redirected_location}"
     )
@@ -252,7 +298,7 @@ async def file_meta(
                 return content_length, etag
             # Otherwise, follow the redirect to get authoritative size/hash
             redirected_location = r.headers.get("location")
-            return await file_meta(model_id, revision, path, redirected_location)
+            return await file_meta(repo_id, revision, path, redirected_location)
         content_length = int(
             r.headers.get("x-linked-size") or r.headers.get("content-length") or 0
         )
@@ -264,7 +310,7 @@ async def file_meta(
 
 
 async def download_file_with_retry(
-    model_id: ModelId,
+    repo_id: str,
     revision: str,
     path: str,
     target_dir: Path,
@@ -274,23 +320,23 @@ async def download_file_with_retry(
     for attempt in range(n_attempts):
         try:
             return await _download_file(
-                model_id, revision, path, target_dir, on_progress
+                repo_id, revision, path, target_dir, on_progress
             )
         except Exception as e:
             if isinstance(e, FileNotFoundError) or attempt == n_attempts - 1:
                 raise e
             logger.error(
-                f"Download error on attempt {attempt}/{n_attempts} for {model_id=} {revision=} {path=} {target_dir=}"
+                f"Download error on attempt {attempt}/{n_attempts} for {repo_id=} {revision=} {path=} {target_dir=}"
             )
             logger.error(traceback.format_exc())
             await asyncio.sleep(min(8, 0.1 * (2.0**attempt)))
     raise Exception(
-        f"Failed to download file {model_id=} {revision=} {path=} {target_dir=}"
+        f"Failed to download file {repo_id=} {revision=} {path=} {target_dir=}"
     )
 
 
 async def _download_file(
-    model_id: ModelId,
+    repo_id: str,
     revision: str,
     path: str,
     target_dir: Path,
@@ -299,7 +345,7 @@ async def _download_file(
     if await aios.path.exists(target_dir / path):
         return target_dir / path
     await aios.makedirs((target_dir / path).parent, exist_ok=True)
-    length, etag = await file_meta(model_id, revision, path)
+    length, etag = await file_meta(repo_id, revision, path)
     remote_hash = etag[:-5] if etag.endswith("-gzip") else etag
     partial_path = target_dir / f"{path}.partial"
     resume_byte_pos = (
@@ -308,7 +354,7 @@ async def _download_file(
         else None
     )
     if resume_byte_pos != length:
-        url = urljoin(f"{get_hf_endpoint()}/{model_id}/resolve/{revision}/", path)
+        url = urljoin(f"{get_hf_endpoint()}/{repo_id}/resolve/{revision}/", path)
         headers = await get_download_headers()
         if resume_byte_pos:
             headers["Range"] = f"bytes={resume_byte_pos}-"
@@ -348,7 +394,7 @@ async def _download_file(
 
 def calculate_repo_progress(
     shard: ShardMetadata,
-    model_id: ModelId,
+    repo_id: str,
     revision: str,
     file_progress: dict[str, RepoFileDownloadProgress],
     all_start_time: float,
@@ -377,7 +423,7 @@ def calculate_repo_progress(
         else "not_started"
     )
     return RepoDownloadProgress(
-        repo_id=model_id,
+        repo_id=repo_id,
         repo_revision=revision,
         shard=shard,
         completed_files=len(
@@ -396,11 +442,11 @@ def calculate_repo_progress(
     )
 
 
-async def get_weight_map(model_id: ModelId, revision: str = "main") -> dict[str, str]:
-    target_dir = (await ensure_models_dir()) / model_id.normalize()
+async def get_weight_map(repo_id: str, revision: str = "main") -> dict[str, str]:
+    target_dir = (await ensure_models_dir()) / str(repo_id).replace("/", "--")
     await aios.makedirs(target_dir, exist_ok=True)
     index_file = await download_file_with_retry(
-        model_id, revision, "model.safetensors.index.json", target_dir
+        repo_id, revision, "model.safetensors.index.json", target_dir
     )
     async with aiofiles.open(index_file, "r") as f:
         index_data = ModelSafetensorsIndex.model_validate_json(await f.read())
@@ -458,7 +504,7 @@ async def download_shard(
     # TODO: currently not recursive. Some models might require subdirectories - thus this will need to be changed.
     #  Update: <- This does not seem to be the case. Yay?
     file_list = await fetch_file_list_with_cache(
-        shard.model_card.model_id, revision, recursive=True
+        str(shard.model_card.model_id), revision, recursive=True
     )
     filtered_file_list = list(
         filter_repo_objects(
@@ -492,7 +538,7 @@ async def download_shard(
             else timedelta(seconds=0)
         )
         file_progress[file.path] = RepoFileDownloadProgress(
-            repo_id=shard.model_card.model_id,
+            repo_id=str(shard.model_card.model_id),
             repo_revision=revision,
             file_path=file.path,
             downloaded=Memory.from_bytes(curr_bytes),
@@ -509,7 +555,7 @@ async def download_shard(
             shard,
             calculate_repo_progress(
                 shard,
-                shard.model_card.model_id,
+                str(shard.model_card.model_id),
                 revision,
                 file_progress,
                 all_start_time,
@@ -519,7 +565,7 @@ async def download_shard(
     for file in filtered_file_list:
         downloaded_bytes = await get_downloaded_size(target_dir / file.path)
         file_progress[file.path] = RepoFileDownloadProgress(
-            repo_id=shard.model_card.model_id,
+            repo_id=str(shard.model_card.model_id),
             repo_revision=revision,
             file_path=file.path,
             downloaded=Memory.from_bytes(downloaded_bytes),
@@ -543,7 +589,7 @@ async def download_shard(
     async def download_with_semaphore(file: FileListEntry) -> None:
         async with semaphore:
             await download_file_with_retry(
-                shard.model_card.model_id,
+                str(shard.model_card.model_id),
                 revision,
                 file.path,
                 target_dir,
@@ -557,7 +603,7 @@ async def download_shard(
             *[download_with_semaphore(file) for file in filtered_file_list]
         )
     final_repo_progress = calculate_repo_progress(
-        shard, shard.model_card.model_id, revision, file_progress, all_start_time
+        shard, str(shard.model_card.model_id), revision, file_progress, all_start_time
     )
     await on_progress(shard, final_repo_progress)
     if gguf := next((f for f in filtered_file_list if f.path.endswith(".gguf")), None):

src/exo/worker/download/impl_shard_downloader.py

@@ -3,7 +3,8 @@ from collections.abc import Awaitable
 from pathlib import Path
 from typing import AsyncIterator, Callable
 
-from exo.shared.models.model_cards import MODEL_CARDS, ModelCard, ModelId
+from exo.shared.models.model_cards import MODEL_CARDS
+from exo.shared.models.model_meta import get_model_card
 from exo.shared.types.worker.shards import (
     PipelineShardMetadata,
     ShardMetadata,
@@ -18,8 +19,8 @@ def exo_shard_downloader(max_parallel_downloads: int = 8) -> ShardDownloader:
     )
 
 
-async def build_base_shard(model_id: ModelId) -> ShardMetadata:
-    model_card = await ModelCard.from_hf(model_id)
+async def build_base_shard(model_id: str) -> ShardMetadata:
+    model_card = await get_model_card(model_id)
     return PipelineShardMetadata(
         model_card=model_card,
         device_rank=0,
@@ -30,7 +31,7 @@ async def build_base_shard(model_id: ModelId) -> ShardMetadata:
     )
 
 
-async def build_full_shard(model_id: ModelId) -> PipelineShardMetadata:
+async def build_full_shard(model_id: str) -> PipelineShardMetadata:
     base_shard = await build_base_shard(model_id)
     return PipelineShardMetadata(
         model_card=base_shard.model_card,
@@ -147,7 +148,7 @@ class ResumableShardDownloader(ShardDownloader):
         self,
     ) -> AsyncIterator[tuple[Path, RepoDownloadProgress]]:
         async def _status_for_model(
-            model_id: ModelId,
+            model_id: str,
         ) -> tuple[Path, RepoDownloadProgress]:
             """Helper coroutine that builds the shard for a model and gets its download status."""
             shard = await build_full_shard(model_id)

src/exo/worker/engines/mlx/auto_parallel.py

@@ -4,7 +4,7 @@ from abc import ABC, abstractmethod
 from collections.abc import Callable
 from functools import partial
 from inspect import signature
-from typing import TYPE_CHECKING, Any, Protocol, cast
+from typing import TYPE_CHECKING, Any, cast
 
 import mlx.core as mx
 import mlx.nn as nn
@@ -67,27 +67,16 @@ def eval_with_timeout(
         completed.set()
 
 
-class _LayerCallable(Protocol):
-    """Structural type that any compatible layer must satisfy.
-
-    We require a single positional input of type ``mx.array`` and an
-    ``mx.array`` output, while permitting arbitrary *args / **kwargs so this
-    protocol matches the vast majority of `mlx.nn.Module` subclasses.
-    """
-
-    def __call__(self, x: mx.array, *args: object, **kwargs: object) -> mx.array: ...
-
-
 class CustomMlxLayer(nn.Module):
     """Base class for replacing an MLX layer with a custom implementation."""
 
-    def __init__(self, original_layer: _LayerCallable):
+    def __init__(self, original_layer: nn.Module):
         super().__init__()
-        dict.__setitem__(self, "_original_layer", original_layer)  # pyright: ignore[reportUnknownMemberType]
+        object.__setattr__(self, "_original_layer", original_layer)
 
     @property
-    def original_layer(self) -> _LayerCallable:
-        return cast(_LayerCallable, self["_original_layer"])
+    def original_layer(self) -> nn.Module:
+        return cast(nn.Module, object.__getattribute__(self, "_original_layer"))
 
     # Calls __getattr__ for any attributes not found on nn.Module (e.g. use_sliding)
     if not TYPE_CHECKING:
@@ -96,56 +85,57 @@ class CustomMlxLayer(nn.Module):
             try:
                 return super().__getattr__(name)
             except AttributeError:
-                original_layer = cast(_LayerCallable, self["_original_layer"])
+                original_layer = object.__getattribute__(self, "_original_layer")
                 return getattr(original_layer, name)
 
 
-class PipelineFirstLayer(CustomMlxLayer):
-    def __init__(
-        self,
-        original_layer: _LayerCallable,
-        r: int,
-        group: mx.distributed.Group,
-    ):
-        super().__init__(original_layer)
-        self.r: int = r
-        self.group = group
+def patch_pipeline_first_layer(
+    pipeline_layer: nn.Module, group: mx.distributed.Group
+) -> nn.Module:
+    cls = type(pipeline_layer)
+    orig_call = cast(Callable[..., mx.array], cls.__call__)
 
-    def __call__(self, x: mx.array, *args: object, **kwargs: object) -> mx.array:
-        if self.r != 0:
-            x = mx.distributed.recv_like(x, (self.r - 1), group=self.group)
-        return self.original_layer(x, *args, **kwargs)
+    rank = group.rank()
+
+    class PatchedFirstLayer(cls):
+        def __call__(self, x: mx.array, *args: object, **kwargs: object) -> mx.array:
+            if rank != 0:
+                x = mx.distributed.recv_like(x, (rank - 1), group=group)
+            return orig_call(self, x, *args, **kwargs)
+
+    pipeline_layer.__class__ = PatchedFirstLayer
+
+    return pipeline_layer
 
 
-class PipelineLastLayer(CustomMlxLayer):
-    def __init__(
-        self,
-        original_layer: _LayerCallable,
-        r: int,
-        s: int,
-        group: mx.distributed.Group,
-    ):
-        super().__init__(original_layer)
-        self.r: int = r
-        self.s: int = s
-        self.group = group
-        self.original_layer_signature = signature(self.original_layer.__call__)
+def patch_pipeline_last_layer(
+    pipeline_layer: nn.Module, group: mx.distributed.Group
+) -> nn.Module:
+    cls = type(pipeline_layer)
+    orig_call = cast(Callable[..., mx.array], cls.__call__)
+    orig_call_sig = signature(orig_call)
 
-    def __call__(self, x: mx.array, *args: object, **kwargs: object) -> mx.array:
-        cache = self.original_layer_signature.bind_partial(
-            x, *args, **kwargs
-        ).arguments.get("cache", None)
+    rank = group.rank()
+    size = group.size()
 
-        output: mx.array = self.original_layer(x, *args, **kwargs)
-
-        if self.r != self.s - 1:
-            output = mx.distributed.send(
-                output, (self.r + 1) % self.s, group=self.group
+    class PatchedLastLayer(cls):
+        def __call__(self, x: mx.array, *args: object, **kwargs: object) -> mx.array:
+            cache = orig_call_sig.bind_partial(x, *args, **kwargs).arguments.get(
+                "cache", None
             )
-            if cache is not None:
-                cache.keys = mx.depends(cache.keys, output)  # type: ignore[reportUnknownMemberType]
 
-        return output
+            output: mx.array = orig_call(self, x, *args, **kwargs)
+
+            if rank != size - 1:
+                output = mx.distributed.send(output, (rank + 1) % size, group=group)
+                if cache is not None:
+                    cache.keys = mx.depends(cache.keys, output)  # type: ignore[reportUnknownMemberType]
+
+            return output
+
+    pipeline_layer.__class__ = PatchedLastLayer
+
+    return pipeline_layer
 
 
 def _inner_model(model: nn.Module) -> nn.Module:
@@ -160,13 +150,13 @@ def _inner_model(model: nn.Module) -> nn.Module:
     raise ValueError("Model must either have a 'model' or 'transformer' attribute")
 
 
-def _get_layers(inner_model_instance: nn.Module) -> list[_LayerCallable]:
+def _get_layers(inner_model_instance: nn.Module) -> list[nn.Module]:
     # Handle both model.layers and model.h cases
-    layers: list[_LayerCallable]
+    layers: list[nn.Module]
     if hasattr(inner_model_instance, "layers"):
-        layers = cast(list[_LayerCallable], inner_model_instance.layers)
+        layers = cast(list[nn.Module], inner_model_instance.layers)
     elif hasattr(inner_model_instance, "h"):
-        layers = cast(list[_LayerCallable], inner_model_instance.h)
+        layers = cast(list[nn.Module], inner_model_instance.h)
     else:
         raise ValueError("Model must have either a 'layers' or 'h' attribute")
 
@@ -191,15 +181,12 @@ def pipeline_auto_parallel(
     layers = _get_layers(inner_model_instance)
 
     start_layer, end_layer = model_shard_meta.start_layer, model_shard_meta.end_layer
-    device_rank, world_size = model_shard_meta.device_rank, model_shard_meta.world_size
 
     layers = layers[start_layer:end_layer]
-    layers[0] = PipelineFirstLayer(layers[0], device_rank, group=group)
-    layers[-1] = PipelineLastLayer(
+    layers[0] = patch_pipeline_first_layer(layers[0], group)
+    layers[-1] = patch_pipeline_last_layer(
         layers[-1],
-        device_rank,
-        world_size,
-        group=group,
+        group,
     )
 
     if isinstance(inner_model_instance, GptOssMoeModel):
@@ -334,7 +321,7 @@ def tensor_auto_parallel(
         group=group,
     )
 
-    if hasattr(model, "shard") and not isinstance(model, GptOssModel):
+    if hasattr(model, "shard"):
         try:
             model.shard(group)  # type: ignore
             return patch_tensor_model(model)
@@ -383,6 +370,7 @@ def tensor_auto_parallel(
             all_to_sharded_linear_in_place,
             sharded_to_all_linear_in_place,
         )
+
     else:
         raise ValueError(f"Unsupported model type: {type(model)}")
 
@@ -445,7 +433,7 @@ class LlamaShardingStrategy(TensorParallelShardingStrategy):
         return model
 
 
-def _set_layers(model: nn.Module, layers: list[_LayerCallable]) -> None:
+def _set_layers(model: nn.Module, layers: list[nn.Module]) -> None:
     inner_model_instance = _inner_model(model)
     if hasattr(inner_model_instance, "layers"):
         inner_model_instance.layers = layers
@@ -520,17 +508,17 @@ class DeepSeekShardingStrategy(TensorParallelShardingStrategy):
 
 
 class ShardedDeepseekV3MoE(CustomMlxLayer):
-    def __init__(self, layer: _LayerCallable):
+    def __init__(self, layer: nn.Module):
         super().__init__(layer)
         self.sharding_group: mx.distributed.Group | None = None
 
     def __call__(self, x: mx.array) -> mx.array:
         if self.sharding_group is not None:
             x = sum_gradients(self.sharding_group)(x)
-        y = self.original_layer.__call__(x)
+        y = self.original_layer.__call__(x)  # type: ignore
         if self.sharding_group is not None:
-            y = mx.distributed.all_sum(y, group=self.sharding_group)
-        return y
+            y = mx.distributed.all_sum(y, group=self.sharding_group)  # type: ignore
+        return y  # type: ignore
 
 
 class MiniMaxShardingStrategy(TensorParallelShardingStrategy):
@@ -564,7 +552,7 @@ class MiniMaxShardingStrategy(TensorParallelShardingStrategy):
             self.all_to_sharded_linear_in_place(
                 layer.block_sparse_moe.switch_mlp.up_proj
             )
-            layer.block_sparse_moe = ShardedQwenMoE(layer.block_sparse_moe)  # pyright: ignore[reportAttributeAccessIssue, reportArgumentType]
+            layer.block_sparse_moe = ShardedQwenMoE(layer.block_sparse_moe)  # pyright: ignore[reportAttributeAccessIssue]
             layer.block_sparse_moe.sharding_group = self.group  # pyright: ignore[reportAttributeAccessIssue]
 
         return model
@@ -598,7 +586,7 @@ class QwenShardingStrategy(TensorParallelShardingStrategy):
                 self.all_to_sharded_linear_in_place(layer.mlp.switch_mlp.gate_proj)
                 self.sharded_to_all_linear_in_place(layer.mlp.switch_mlp.down_proj)
                 self.all_to_sharded_linear_in_place(layer.mlp.switch_mlp.up_proj)
-                layer.mlp = ShardedQwenMoE(layer.mlp)  # pyright: ignore[reportAttributeAccessIssue, reportArgumentType]
+                layer.mlp = ShardedQwenMoE(layer.mlp)  # pyright: ignore[reportAttributeAccessIssue]
                 layer.mlp.sharding_group = self.group
 
             # Shard the MLP
@@ -611,17 +599,17 @@ class QwenShardingStrategy(TensorParallelShardingStrategy):
 
 
 class ShardedQwenMoE(CustomMlxLayer):
-    def __init__(self, layer: _LayerCallable):
+    def __init__(self, layer: nn.Module):
         super().__init__(layer)
         self.sharding_group: mx.distributed.Group | None = None
 
     def __call__(self, x: mx.array) -> mx.array:
         if self.sharding_group is not None:
             x = sum_gradients(self.sharding_group)(x)
-        y = self.original_layer.__call__(x)
+        y = self.original_layer.__call__(x)  # type: ignore
         if self.sharding_group is not None:
-            y = mx.distributed.all_sum(y, group=self.sharding_group)
-        return y
+            y = mx.distributed.all_sum(y, group=self.sharding_group)  # type: ignore
+        return y  # type: ignore
 
 
 class GptOssShardingStrategy(TensorParallelShardingStrategy):
@@ -673,7 +661,7 @@ class ShardedGptOssMoE(CustomMlxLayer):
     def __call__(self, x: mx.array) -> mx.array:
         if self.sharding_group is not None:
             x = sum_gradients(self.sharding_group)(x)
-        y = self.original_layer(x)
+        y = self.original_layer(x)  # type: ignore
         if self.sharding_group is not None:
-            y = mx.distributed.all_sum(y, group=self.sharding_group)
-        return y
+            y = mx.distributed.all_sum(y, group=self.sharding_group)  # type: ignore
+        return y  # type: ignore

src/exo/worker/engines/mlx/utils_mlx.py

@@ -23,7 +23,6 @@ from mlx_lm.models.deepseek_v3 import DeepseekV3Model
 from mlx_lm.models.gpt_oss import Model as GptOssModel
 from mlx_lm.tokenizer_utils import TokenizerWrapper
 
-from exo.shared.models.model_cards import ModelId
 from exo.worker.engines.mlx.constants import (
     CACHE_GROUP_SIZE,
     KV_CACHE_BITS,
@@ -297,7 +296,7 @@ def get_tokenizer(model_path: Path, shard_metadata: ShardMetadata) -> TokenizerW
     return load_tokenizer_for_model_id(shard_metadata.model_card.model_id, model_path)
 
 
-def get_eos_token_ids_for_model(model_id: ModelId) -> list[int] | None:
+def get_eos_token_ids_for_model(model_id: str) -> list[int] | None:
     """
     Get the EOS token IDs for a model based on its ID.
 
@@ -321,9 +320,7 @@ def get_eos_token_ids_for_model(model_id: ModelId) -> list[int] | None:
     return None
 
 
-def load_tokenizer_for_model_id(
-    model_id: ModelId, model_path: Path
-) -> TokenizerWrapper:
+def load_tokenizer_for_model_id(model_id: str, model_path: Path) -> TokenizerWrapper:
     """
     Load tokenizer for a model given its ID and local path.
 

src/exo/worker/runner/runner.py

@@ -1,8 +1,6 @@
-import json
 import time
 from collections.abc import Generator
 from functools import cache
-from typing import Any, Callable, cast
 
 import mlx.core as mx
 from mlx_lm.models.gpt_oss import Model as GptOssModel
@@ -13,10 +11,9 @@ from openai_harmony import (  # pyright: ignore[reportMissingTypeStubs]
     StreamableParser,
     load_harmony_encoding,
 )
-from pydantic import ValidationError
 
 from exo.shared.types.api import ChatCompletionMessageText
-from exo.shared.types.chunks import TokenChunk, ToolCallChunk
+from exo.shared.types.chunks import TokenChunk
 from exo.shared.types.events import (
     ChunkGenerated,
     Event,
@@ -36,8 +33,6 @@ from exo.shared.types.tasks import (
 from exo.shared.types.worker.instances import BoundInstance
 from exo.shared.types.worker.runner_response import (
     GenerationResponse,
-    ToolCallItem,
-    ToolCallResponse,
 )
 from exo.shared.types.worker.runners import (
     RunnerConnected,
@@ -207,13 +202,7 @@ def main(
                                 mlx_generator, tokenizer
                             )
 
-                        # TODO: Add  call parser here
-                        if (
-                            tokenizer.tool_parser  # pyright: ignore[reportAny]
-                            or tokenizer.tool_call_start
-                            or tokenizer.tool_call_end
-                        ) is not None:
-                            mlx_generator = parse_tool_calls(mlx_generator, tokenizer)
+                        # TODO: Add tool call parser here
 
                         for response in mlx_generator:
                             match response:
@@ -223,7 +212,7 @@ def main(
                                             ChunkGenerated(
                                                 command_id=command_id,
                                                 chunk=TokenChunk(
-                                                    idx=response.token,  # hang on --- is this wrong?? this is totally wrong
+                                                    idx=response.token,
                                                     model=shard_metadata.model_card.model_id,
                                                     text=response.text,
                                                     token_id=response.token,
@@ -232,18 +221,6 @@ def main(
                                                 ),
                                             )
                                         )
-                                case ToolCallResponse():
-                                    if device_rank == 0:
-                                        event_sender.send(
-                                            ChunkGenerated(
-                                                command_id=command_id,
-                                                chunk=ToolCallChunk(
-                                                    idx=4,
-                                                    tool_calls=response.tool_calls,
-                                                    model=shard_metadata.model_card.model_id,
-                                                ),
-                                            )
-                                        )
 
                     # can we make this more explicit?
                     except Exception as e:
@@ -352,50 +329,6 @@ def parse_thinking_models(
         yield response
 
 
-def parse_tool_calls(
-    responses: Generator[GenerationResponse],
-    tokenizer: TokenizerWrapper,
-) -> Generator[GenerationResponse | ToolCallResponse]:
-    assert tokenizer.tool_call_start is not None
-    assert tokenizer.tool_call_end is not None
-    tool_parser = cast(
-        Callable[[str], dict[str, Any] | list[dict[str, Any]]] | None,
-        tokenizer.tool_parser,
-    )  # first arg has followup args, but we don't care about them rn
-    assert tool_parser is not None
-    in_tool_call = False
-    tool_call_text_parts: list[str] = []
-    for response in responses:
-        # assumption: the tool call start is one token
-        if response.text == tokenizer.tool_call_start:
-            in_tool_call = True
-            continue
-        if in_tool_call:
-            tool_call_text_parts.append(response.text)
-            continue
-        # assumption: the tool call end is one token
-        if response.text == tokenizer.tool_call_end:
-            try:
-                # tool_parser returns an arbitrarily nested python dictionary
-                # we actually don't want the python dictionary, we just want to
-                # parse the top level { function: ..., arguments: ... } structure
-                # as we're just gonna hand it back to the api anyway
-                parsed = tool_parser("".join(tool_call_text_parts).strip())
-                if isinstance(parsed, list):
-                    tools = [
-                        ToolCallItem.model_validate_json(json.dumps(tool))
-                        for tool in parsed
-                    ]
-                else:
-                    tools = [ToolCallItem.model_validate_json(json.dumps(parsed))]
-                yield ToolCallResponse(tool_calls=tools)
-            except (json.JSONDecodeError, ValidationError):
-                in_tool_call = False
-                tool_call_text_parts = []
-        # fallthrough
-        yield response
-
-
 EXO_RUNNER_MUST_FAIL = "EXO RUNNER MUST FAIL"
 EXO_RUNNER_MUST_OOM = "EXO RUNNER MUST OOM"
 EXO_RUNNER_MUST_TIMEOUT = "EXO RUNNER MUST TIMEOUT"

src/exo/worker/tests/unittests/test_mlx/conftest.py

@@ -11,15 +11,14 @@ import mlx.core as mx
 import mlx.nn as nn
 
 from exo.shared.constants import EXO_MODELS_DIR
-from exo.shared.models.model_cards import ModelCard
+from exo.shared.models.model_cards import ModelCard, ModelId
 from exo.shared.types.api import ChatCompletionMessage
-from exo.shared.types.common import ModelId
 from exo.shared.types.memory import Memory
 from exo.shared.types.tasks import ChatCompletionTaskParams
 from exo.shared.types.worker.shards import PipelineShardMetadata, TensorShardMetadata
 from exo.worker.engines.mlx import Model
 from exo.worker.engines.mlx.generator.generate import mlx_generate
-from exo.worker.engines.mlx.utils_mlx import shard_and_load
+from exo.worker.engines.mlx.utils_mlx import shard_and_load, apply_chat_template
 
 
 class MockLayer(nn.Module):
@@ -117,12 +116,11 @@ def run_gpt_oss_pipeline_device(
             messages=[ChatCompletionMessage(role="user", content=prompt_text)],
             max_tokens=max_tokens,
         )
+        prompt = apply_chat_template(tokenizer, task)
 
         generated_text = ""
         for response in mlx_generate(
-            model=model,
-            tokenizer=tokenizer,
-            task=task,
+            model=model, tokenizer=tokenizer, task=task, prompt=prompt
         ):
             generated_text += response.text
             if response.finish_reason is not None:
@@ -184,11 +182,11 @@ def run_gpt_oss_tensor_parallel_device(
             max_tokens=max_tokens,
         )
 
+        prompt = apply_chat_template(tokenizer, task)
+
         generated_text = ""
         for response in mlx_generate(
-            model=model,
-            tokenizer=tokenizer,
-            task=task,
+            model=model, tokenizer=tokenizer, task=task, prompt=prompt
         ):
             generated_text += response.text
             if response.finish_reason is not None:

src/exo/worker/tests/unittests/test_mlx/test_auto_parallel.py

@@ -10,8 +10,8 @@ import pytest
 
 from exo.worker.engines.mlx.auto_parallel import (
     CustomMlxLayer,
-    PipelineFirstLayer,
-    PipelineLastLayer,
+    patch_pipeline_first_layer,
+    patch_pipeline_last_layer,
     patch_pipeline_model,
 )
 from exo.worker.tests.unittests.test_mlx.conftest import MockLayer
@@ -50,8 +50,8 @@ def run_pipeline_device(
         group = mx.distributed.init(backend="ring", strict=True)
 
         mock = MockLayerInner()
-        first = PipelineFirstLayer(mock, r=rank, group=group)
-        composed = PipelineLastLayer(first, r=rank, s=world_size, group=group)
+        first = patch_pipeline_first_layer(mock, group)
+        composed = patch_pipeline_last_layer(first, group)
 
         # Wrap in a mock model, then wrap in PipelineParallelModel for all_gather
         inner_model = MockModel([composed])
@@ -78,8 +78,8 @@ def test_composed_wrappers_delegate_attributes() -> None:
     mock = MockLayer()
     group = mx.distributed.init()
 
-    first = PipelineFirstLayer(mock, r=0, group=group)
-    composed = PipelineLastLayer(first, r=0, s=1, group=group)
+    first = patch_pipeline_first_layer(mock, group)
+    composed = patch_pipeline_last_layer(first, group)
 
     assert composed.custom_attr == "test_value"  # type: ignore[attr-defined]
     assert composed.use_sliding is True  # type: ignore[attr-defined]

src/exo/worker/tests/unittests/test_mlx/test_tokenizers.py

@@ -11,7 +11,7 @@ from pathlib import Path
 
 import pytest
 
-from exo.shared.models.model_cards import MODEL_CARDS, ModelCard, ModelId
+from exo.shared.models.model_cards import MODEL_CARDS, ModelCard
 from exo.worker.download.download_utils import (
     download_file_with_retry,
     ensure_models_dir,
@@ -50,9 +50,9 @@ def is_tokenizer_file(filename: str) -> bool:
     return False
 
 
-async def download_tokenizer_files(model_id: ModelId) -> Path:
+async def download_tokenizer_files(model_id: str) -> Path:
     """Download only the tokenizer-related files for a model."""
-    target_dir = await ensure_models_dir() / model_id.normalize()
+    target_dir = await ensure_models_dir() / model_id.replace("/", "--")
     target_dir.mkdir(parents=True, exist_ok=True)
 
     file_list = await fetch_file_list_with_cache(model_id, "main", recursive=True)
@@ -72,22 +72,22 @@ async def download_tokenizer_files(model_id: ModelId) -> Path:
 
 
 # Get a sample of models to test (one per family to keep tests fast)
-def get_test_models() -> list[ModelCard]:
+def get_test_models() -> list[tuple[str, ModelCard]]:
     """Get a representative sample of models to test."""
     # Pick one model from each family to test
-    families: dict[str, ModelCard] = {}
-    for card in MODEL_CARDS.values():
+    families: dict[str, tuple[str, ModelCard]] = {}
+    for _, card in MODEL_CARDS.items():
         # Extract family name (e.g., "llama-3.1" from "llama-3.1-8b")
         parts = card.model_id.short().split("-")
         family = "-".join(parts[:2]) if len(parts) >= 2 else parts[0]
 
         if family not in families:
-            families[family] = card
+            families[family] = (card.model_id.short(), card)
 
     return list(families.values())
 
 
-TEST_MODELS: list[ModelCard] = get_test_models()
+TEST_MODELS: list[tuple[str, ModelCard]] = get_test_models()
 
 pytestmark = pytest.mark.slow
 
@@ -101,13 +101,14 @@ def event_loop():
 
 
 @pytest.mark.parametrize(
-    "model_card",
+    "short_id,model_card",
     TEST_MODELS,
+    ids=[m[0] for m in TEST_MODELS],
 )
 @pytest.mark.asyncio
 async def test_tokenizer_encode_decode(short_id: str, model_card: ModelCard) -> None:
     """Test that tokenizer can encode and decode text correctly."""
-    model_id = model_card.model_id
+    model_id = str(model_card.model_id)
 
     # Download tokenizer files
     model_path = await download_tokenizer_files(model_id)
@@ -166,15 +167,16 @@ async def test_tokenizer_encode_decode(short_id: str, model_card: ModelCard) ->
 
 
 @pytest.mark.parametrize(
-    "model_card",
+    "short_id,model_card",
     TEST_MODELS,
+    ids=[m[0] for m in TEST_MODELS],
 )
 @pytest.mark.asyncio
 async def test_tokenizer_has_required_attributes(
     short_id: str, model_card: ModelCard
 ) -> None:
     """Test that tokenizer has required attributes for inference."""
-    model_id = model_card.model_id
+    model_id = str(model_card.model_id)
 
     model_path = await download_tokenizer_files(model_id)
 
@@ -207,18 +209,19 @@ async def test_tokenizer_has_required_attributes(
 
 
 @pytest.mark.parametrize(
-    "model_card",
+    "short_id,model_card",
     TEST_MODELS,
+    ids=[m[0] for m in TEST_MODELS],
 )
 @pytest.mark.asyncio
-async def test_tokenizer_special_tokens(model_card: ModelCard) -> None:
+async def test_tokenizer_special_tokens(short_id: str, model_card: ModelCard) -> None:
     """Test that tokenizer can encode text containing special tokens.
 
     This is critical because the actual inference path uses prompts with
     special tokens from chat templates. If special tokens aren't handled
     correctly, encoding will fail.
     """
-    model_id = model_card.model_id
+    model_id = str(model_card.model_id)
 
     model_path = await download_tokenizer_files(model_id)
 
@@ -298,14 +301,16 @@ async def test_tokenizer_special_tokens(model_card: ModelCard) -> None:
 async def test_kimi_tokenizer_specifically():
     """Test Kimi tokenizer with its specific patches and quirks."""
     kimi_models = [
-        card for card in MODEL_CARDS.values() if "kimi" in card.model_id.lower()
+        (short_id, card)
+        for short_id, card in MODEL_CARDS.items()
+        if "kimi" in short_id.lower()
     ]
 
     if not kimi_models:
         pytest.skip("No Kimi models found in MODEL_CARDS")
 
-    model_card = kimi_models[0]
-    model_id = model_card.model_id
+    _, model_card = kimi_models[0]
+    model_id = str(model_card.model_id)
 
     model_path = await download_tokenizer_files(model_id)
 
@@ -344,15 +349,17 @@ async def test_kimi_tokenizer_specifically():
 @pytest.mark.asyncio
 async def test_glm_tokenizer_specifically():
     """Test GLM tokenizer with its specific EOS tokens."""
-    glm_model_cards = [
-        card for card in MODEL_CARDS.values() if "glm" in card.model_id.lower()
+    glm_models = [
+        (short_id, card)
+        for short_id, card in MODEL_CARDS.items()
+        if "glm" in short_id.lower()
     ]
 
-    if not glm_model_cards:
+    if not glm_models:
         pytest.skip("No GLM models found in MODEL_CARDS")
 
-    model_card = glm_model_cards[0]
-    model_id = model_card.model_id
+    _, model_card = glm_models[0]
+    model_id = str(model_card.model_id)
 
     model_path = await download_tokenizer_files(model_id)
 

src/exo/worker/tests/unittests/test_plan/test_download_and_loading.py

@@ -1,5 +1,6 @@
 import exo.worker.plan as plan_mod
-from exo.shared.types.common import ModelId, NodeId
+from exo.shared.models.model_cards import ModelId
+from exo.shared.types.common import NodeId
 from exo.shared.types.memory import Memory
 from exo.shared.types.tasks import LoadModel
 from exo.shared.types.worker.downloads import DownloadCompleted, DownloadProgress

uv.lock

@@ -248,7 +248,6 @@ dependencies = [
     { name = "pydantic", marker = "sys_platform == 'darwin' or sys_platform == 'linux'" },
     { name = "rustworkx", marker = "sys_platform == 'darwin' or sys_platform == 'linux'" },
     { name = "tiktoken", marker = "sys_platform == 'darwin' or sys_platform == 'linux'" },
-    { name = "tomlkit", marker = "sys_platform == 'darwin' or sys_platform == 'linux'" },
     { name = "types-aiofiles", marker = "sys_platform == 'darwin' or sys_platform == 'linux'" },
 ]
 
@@ -282,7 +281,6 @@ requires-dist = [
     { name = "pydantic", specifier = ">=2.11.7" },
     { name = "rustworkx", specifier = ">=0.17.1" },
     { name = "tiktoken", specifier = ">=0.12.0" },
-    { name = "tomlkit", specifier = ">=0.14.0" },
     { name = "types-aiofiles", specifier = ">=24.1.0.20250708" },
 ]
 
@@ -317,16 +315,6 @@ dev = [
     { name = "pytest-asyncio", specifier = ">=1.0.0" },
 ]
 
-[[package]]
-name = "tomlkit"
-version = "0.14.0"
-source = { registry = "https://pypi.org/simple" }
-sdist = { url = "https://files.pythonhosted.org/packages/c3/af/14b24e41977adb296d6bd1fb59402cf7d60ce364f90c890bd2ec65c43b5a/tomlkit-0.14.0.tar.gz", hash = "sha256:cf00efca415dbd57575befb1f6634c4f42d2d87dbba376128adb42c121b87064", size = 187167 }
-wheels = [
-    { url = "https://files.pythonhosted.org/packages/b5/11/87d6d29fb5d237229d67973a6c9e06e048f01cf4994dee194ab0ea841814/tomlkit-0.14.0-py3-none-any.whl", hash = "sha256:592064ed85b40fa213469f81ac584f67a4f2992509a7c3ea2d632208623a3680", size = 39310 },
-]
-
-
 [[package]]
 name = "fastapi"
 version = "0.128.0"