Ensure unique model Id for each quant

## Why It Works

Same implementation as FLUX.1-dev, just different weights

dashboard/src/lib/stores/app.svelte.ts

@@ -216,6 +216,8 @@ export interface Message {
   attachments?: MessageAttachment[];
   ttftMs?: number; // Time to first token in ms (for assistant messages)
   tps?: number; // Tokens per second (for assistant messages)
+  requestType?: "chat" | "image-generation" | "image-editing";
+  sourceImageDataUrl?: string; // For image editing regeneration
 }
 
 export interface Conversation {
@@ -1270,10 +1272,46 @@ class AppStore {
 
     if (lastUserIndex === -1) return;
 
-    // Remove any messages after the user message
-    this.messages = this.messages.slice(0, lastUserIndex + 1);
+    const lastUserMessage = this.messages[lastUserIndex];
+    const requestType = lastUserMessage.requestType || "chat";
+    const prompt = lastUserMessage.content;
 
-    // Resend the message to get a new response
+    // Remove messages after user message (including the user message for image requests
+    // since generateImage/editImage will re-add it)
+    this.messages = this.messages.slice(0, lastUserIndex);
+
+    switch (requestType) {
+      case "image-generation":
+        await this.generateImage(prompt);
+        break;
+      case "image-editing":
+        if (lastUserMessage.sourceImageDataUrl) {
+          await this.editImage(prompt, lastUserMessage.sourceImageDataUrl);
+        } else {
+          // Can't regenerate edit without source image - restore user message and show error
+          this.messages.push(lastUserMessage);
+          const errorMessage = this.addMessage("assistant", "");
+          const idx = this.messages.findIndex((m) => m.id === errorMessage.id);
+          if (idx !== -1) {
+            this.messages[idx].content =
+              "Error: Cannot regenerate image edit - source image not found";
+          }
+          this.updateActiveConversation();
+        }
+        break;
+      case "chat":
+      default:
+        // Restore the user message for chat regeneration
+        this.messages.push(lastUserMessage);
+        await this.regenerateChatCompletion();
+        break;
+    }
+  }
+
+  /**
+   * Helper method to regenerate a chat completion response
+   */
+  private async regenerateChatCompletion(): Promise<void> {
     this.isLoading = true;
     this.currentResponse = "";
 
@@ -1788,6 +1826,7 @@ class AppStore {
       role: "user",
       content: prompt,
       timestamp: Date.now(),
+      requestType: "image-generation",
     };
     this.messages.push(userMessage);
 
@@ -1998,6 +2037,8 @@ class AppStore {
       role: "user",
       content: prompt,
       timestamp: Date.now(),
+      requestType: "image-editing",
+      sourceImageDataUrl: imageDataUrl,
     };
     this.messages.push(userMessage);
 
@@ -2187,6 +2228,54 @@ class AppStore {
       this.conversations.find((c) => c.id === this.activeConversationId) || null
     );
   }
+
+  /**
+   * Start a download on a specific node
+   */
+  async startDownload(nodeId: string, shardMetadata: object): Promise<void> {
+    try {
+      const response = await fetch("/download/start", {
+        method: "POST",
+        headers: { "Content-Type": "application/json" },
+        body: JSON.stringify({
+          targetNodeId: nodeId,
+          shardMetadata: shardMetadata,
+        }),
+      });
+      if (!response.ok) {
+        const errorText = await response.text();
+        throw new Error(
+          `Failed to start download: ${response.status} - ${errorText}`,
+        );
+      }
+    } catch (error) {
+      console.error("Error starting download:", error);
+      throw error;
+    }
+  }
+
+  /**
+   * Delete a downloaded model from a specific node
+   */
+  async deleteDownload(nodeId: string, modelId: string): Promise<void> {
+    try {
+      const response = await fetch(
+        `/download/${encodeURIComponent(nodeId)}/${encodeURIComponent(modelId)}`,
+        {
+          method: "DELETE",
+        },
+      );
+      if (!response.ok) {
+        const errorText = await response.text();
+        throw new Error(
+          `Failed to delete download: ${response.status} - ${errorText}`,
+        );
+      }
+    } catch (error) {
+      console.error("Error deleting download:", error);
+      throw error;
+    }
+  }
 }
 
 export const appStore = new AppStore();
@@ -2292,3 +2381,9 @@ export const setImageGenerationParams = (
 ) => appStore.setImageGenerationParams(params);
 export const resetImageGenerationParams = () =>
   appStore.resetImageGenerationParams();
+
+// Download actions
+export const startDownload = (nodeId: string, shardMetadata: object) =>
+  appStore.startDownload(nodeId, shardMetadata);
+export const deleteDownload = (nodeId: string, modelId: string) =>
+  appStore.deleteDownload(nodeId, modelId);

dashboard/src/routes/downloads/+page.svelte

@@ -6,6 +6,8 @@
     type DownloadProgress,
     refreshState,
     lastUpdate as lastUpdateStore,
+    startDownload,
+    deleteDownload,
   } from "$lib/stores/app.svelte";
   import HeaderNav from "$lib/components/HeaderNav.svelte";
 
@@ -28,6 +30,7 @@
     etaMs: number;
     status: "completed" | "downloading";
     files: FileProgress[];
+    shardMetadata?: Record<string, unknown>;
   };
 
   type NodeEntry = {
@@ -269,6 +272,12 @@
             }
           }
 
+          // Extract shard_metadata for use with download actions
+          const shardMetadata = (downloadPayload.shard_metadata ??
+            downloadPayload.shardMetadata) as
+            | Record<string, unknown>
+            | undefined;
+
           const entry: ModelEntry = {
             modelId,
             prettyName,
@@ -285,6 +294,7 @@
                 ? "completed"
                 : "downloading",
             files,
+            shardMetadata,
           };
 
           const existing = modelMap.get(modelId);
@@ -469,6 +479,52 @@
                     >
                       {pct.toFixed(1)}%
                     </span>
+                    {#if model.status !== "completed" && model.shardMetadata}
+                      <button
+                        type="button"
+                        class="text-exo-light-gray hover:text-exo-yellow transition-colors"
+                        onclick={() =>
+                          startDownload(node.nodeId, model.shardMetadata!)}
+                        title="Start download"
+                      >
+                        <svg
+                          class="w-4 h-4"
+                          viewBox="0 0 20 20"
+                          fill="none"
+                          stroke="currentColor"
+                          stroke-width="2"
+                        >
+                          <path
+                            d="M10 3v10m0 0l-3-3m3 3l3-3M3 17h14"
+                            stroke-linecap="round"
+                            stroke-linejoin="round"
+                          ></path>
+                        </svg>
+                      </button>
+                    {/if}
+                    {#if model.status === "completed"}
+                      <button
+                        type="button"
+                        class="text-exo-light-gray hover:text-red-400 transition-colors"
+                        onclick={() =>
+                          deleteDownload(node.nodeId, model.modelId)}
+                        title="Delete download"
+                      >
+                        <svg
+                          class="w-4 h-4"
+                          viewBox="0 0 20 20"
+                          fill="none"
+                          stroke="currentColor"
+                          stroke-width="2"
+                        >
+                          <path
+                            d="M4 6h12M8 6V4h4v2m1 0v10a1 1 0 01-1 1H8a1 1 0 01-1-1V6h6"
+                            stroke-linecap="round"
+                            stroke-linejoin="round"
+                          ></path>
+                        </svg>
+                      </button>
+                    {/if}
                     <button
                       type="button"
                       class="text-exo-light-gray hover:text-exo-yellow transition-colors"

pyproject.toml

@@ -26,7 +26,7 @@ dependencies = [
     "httpx>=0.28.1",
     "tomlkit>=0.14.0",
     "pillow>=11.0,<12.0", # compatibility with mflux
-    "mflux>=0.14.2",
+    "mflux==0.15.4",
     "python-multipart>=0.0.21",
 ]
 

src/exo/download/coordinator.py

@@ -0,0 +1,284 @@
+import asyncio
+from dataclasses import dataclass, field
+from typing import Iterator
+
+import anyio
+from anyio import current_time
+from anyio.abc import TaskGroup
+from loguru import logger
+
+from exo.download.download_utils import (
+    RepoDownloadProgress,
+    delete_model,
+    map_repo_download_progress_to_download_progress_data,
+)
+from exo.download.shard_downloader import ShardDownloader
+from exo.shared.models.model_cards import ModelId
+from exo.shared.types.commands import (
+    DeleteDownload,
+    ForwarderDownloadCommand,
+    StartDownload,
+)
+from exo.shared.types.common import NodeId, SessionId
+from exo.shared.types.events import (
+    Event,
+    ForwarderEvent,
+    NodeDownloadProgress,
+)
+from exo.shared.types.worker.downloads import (
+    DownloadCompleted,
+    DownloadFailed,
+    DownloadOngoing,
+    DownloadPending,
+    DownloadProgress,
+)
+from exo.shared.types.worker.shards import ShardMetadata
+from exo.utils.channels import Receiver, Sender, channel
+
+
+@dataclass
+class DownloadCoordinator:
+    node_id: NodeId
+    session_id: SessionId
+    shard_downloader: ShardDownloader
+    download_command_receiver: Receiver[ForwarderDownloadCommand]
+    local_event_sender: Sender[ForwarderEvent]
+    event_index_counter: Iterator[int]
+
+    # Local state
+    download_status: dict[ModelId, DownloadProgress] = field(default_factory=dict)
+    active_downloads: dict[ModelId, asyncio.Task[None]] = field(default_factory=dict)
+
+    # Internal event channel for forwarding (initialized in __post_init__)
+    event_sender: Sender[Event] = field(init=False)
+    event_receiver: Receiver[Event] = field(init=False)
+    _tg: TaskGroup = field(init=False)
+
+    def __post_init__(self) -> None:
+        self.event_sender, self.event_receiver = channel[Event]()
+        self._tg = anyio.create_task_group()
+
+    async def run(self) -> None:
+        logger.info("Starting DownloadCoordinator")
+        async with self._tg as tg:
+            tg.start_soon(self._command_processor)
+            tg.start_soon(self._forward_events)
+            tg.start_soon(self._emit_existing_download_progress)
+
+    def shutdown(self) -> None:
+        self._tg.cancel_scope.cancel()
+
+    async def _command_processor(self) -> None:
+        with self.download_command_receiver as commands:
+            async for cmd in commands:
+                # Only process commands targeting this node
+                if cmd.command.target_node_id != self.node_id:
+                    continue
+
+                match cmd.command:
+                    case StartDownload(shard_metadata=shard):
+                        await self._start_download(shard)
+                    case DeleteDownload(model_id=model_id):
+                        await self._delete_download(model_id)
+
+    async def _start_download(self, shard: ShardMetadata) -> None:
+        model_id = shard.model_card.model_id
+
+        # Check if already downloading or complete
+        if model_id in self.download_status:
+            status = self.download_status[model_id]
+            if isinstance(status, (DownloadOngoing, DownloadCompleted)):
+                logger.debug(
+                    f"Download for {model_id} already in progress or complete, skipping"
+                )
+                return
+
+        # Emit pending status
+        progress = DownloadPending(shard_metadata=shard, node_id=self.node_id)
+        self.download_status[model_id] = progress
+        await self.event_sender.send(NodeDownloadProgress(download_progress=progress))
+
+        # Check initial status from downloader
+        initial_progress = (
+            await self.shard_downloader.get_shard_download_status_for_shard(shard)
+        )
+
+        if initial_progress.status == "complete":
+            completed = DownloadCompleted(
+                shard_metadata=shard,
+                node_id=self.node_id,
+                total_bytes=initial_progress.total_bytes,
+            )
+            self.download_status[model_id] = completed
+            await self.event_sender.send(
+                NodeDownloadProgress(download_progress=completed)
+            )
+            return
+
+        # Start actual download
+        self._start_download_task(shard, initial_progress)
+
+    def _start_download_task(
+        self, shard: ShardMetadata, initial_progress: RepoDownloadProgress
+    ) -> None:
+        model_id = shard.model_card.model_id
+
+        # Emit ongoing status
+        status = DownloadOngoing(
+            node_id=self.node_id,
+            shard_metadata=shard,
+            download_progress=map_repo_download_progress_to_download_progress_data(
+                initial_progress
+            ),
+        )
+        self.download_status[model_id] = status
+        self.event_sender.send_nowait(NodeDownloadProgress(download_progress=status))
+
+        last_progress_time = 0.0
+        throttle_interval_secs = 1.0
+
+        async def download_progress_callback(
+            callback_shard: ShardMetadata, progress: RepoDownloadProgress
+        ) -> None:
+            nonlocal last_progress_time
+
+            if progress.status == "complete":
+                completed = DownloadCompleted(
+                    shard_metadata=callback_shard,
+                    node_id=self.node_id,
+                    total_bytes=progress.total_bytes,
+                )
+                self.download_status[callback_shard.model_card.model_id] = completed
+                await self.event_sender.send(
+                    NodeDownloadProgress(download_progress=completed)
+                )
+                # Clean up active download tracking
+                if callback_shard.model_card.model_id in self.active_downloads:
+                    del self.active_downloads[callback_shard.model_card.model_id]
+            elif (
+                progress.status == "in_progress"
+                and current_time() - last_progress_time > throttle_interval_secs
+            ):
+                ongoing = DownloadOngoing(
+                    node_id=self.node_id,
+                    shard_metadata=callback_shard,
+                    download_progress=map_repo_download_progress_to_download_progress_data(
+                        progress
+                    ),
+                )
+                self.download_status[callback_shard.model_card.model_id] = ongoing
+                await self.event_sender.send(
+                    NodeDownloadProgress(download_progress=ongoing)
+                )
+                last_progress_time = current_time()
+
+        self.shard_downloader.on_progress(download_progress_callback)
+
+        async def download_wrapper() -> None:
+            try:
+                await self.shard_downloader.ensure_shard(shard)
+            except Exception as e:
+                logger.error(f"Download failed for {model_id}: {e}")
+                failed = DownloadFailed(
+                    shard_metadata=shard,
+                    node_id=self.node_id,
+                    error_message=str(e),
+                )
+                self.download_status[model_id] = failed
+                await self.event_sender.send(
+                    NodeDownloadProgress(download_progress=failed)
+                )
+            finally:
+                if model_id in self.active_downloads:
+                    del self.active_downloads[model_id]
+
+        task = asyncio.create_task(download_wrapper())
+        self.active_downloads[model_id] = task
+
+    async def _delete_download(self, model_id: ModelId) -> None:
+        # Cancel if active
+        if model_id in self.active_downloads:
+            logger.info(f"Cancelling active download for {model_id} before deletion")
+            self.active_downloads[model_id].cancel()
+            del self.active_downloads[model_id]
+
+        # Delete from disk
+        logger.info(f"Deleting model files for {model_id}")
+        deleted = await delete_model(model_id)
+
+        if deleted:
+            logger.info(f"Successfully deleted model {model_id}")
+        else:
+            logger.warning(f"Model {model_id} was not found on disk")
+
+        # Emit pending status to reset UI state, then remove from local tracking
+        if model_id in self.download_status:
+            current_status = self.download_status[model_id]
+            pending = DownloadPending(
+                shard_metadata=current_status.shard_metadata,
+                node_id=self.node_id,
+            )
+            await self.event_sender.send(
+                NodeDownloadProgress(download_progress=pending)
+            )
+            del self.download_status[model_id]
+
+    async def _forward_events(self) -> None:
+        with self.event_receiver as events:
+            async for event in events:
+                idx = next(self.event_index_counter)
+                fe = ForwarderEvent(
+                    origin_idx=idx,
+                    origin=self.node_id,
+                    session=self.session_id,
+                    event=event,
+                )
+                logger.debug(
+                    f"DownloadCoordinator published event {idx}: {str(event)[:100]}"
+                )
+                await self.local_event_sender.send(fe)
+
+    async def _emit_existing_download_progress(self) -> None:
+        try:
+            while True:
+                logger.info(
+                    "DownloadCoordinator: Fetching and emitting existing download progress..."
+                )
+                async for (
+                    _,
+                    progress,
+                ) in self.shard_downloader.get_shard_download_status():
+                    if progress.status == "complete":
+                        status: DownloadProgress = DownloadCompleted(
+                            node_id=self.node_id,
+                            shard_metadata=progress.shard,
+                            total_bytes=progress.total_bytes,
+                        )
+                    elif progress.status in ["in_progress", "not_started"]:
+                        if progress.downloaded_bytes_this_session.in_bytes == 0:
+                            status = DownloadPending(
+                                node_id=self.node_id, shard_metadata=progress.shard
+                            )
+                        else:
+                            status = DownloadOngoing(
+                                node_id=self.node_id,
+                                shard_metadata=progress.shard,
+                                download_progress=map_repo_download_progress_to_download_progress_data(
+                                    progress
+                                ),
+                            )
+                    else:
+                        continue
+
+                    self.download_status[progress.shard.model_card.model_id] = status
+                    await self.event_sender.send(
+                        NodeDownloadProgress(download_progress=status)
+                    )
+                logger.info(
+                    "DownloadCoordinator: Done emitting existing download progress."
+                )
+                await anyio.sleep(5 * 60)  # 5 minutes
+        except Exception as e:
+            logger.error(
+                f"DownloadCoordinator: Error emitting existing download progress: {e}"
+            )

src/exo/download/download_utils.py

@@ -24,7 +24,15 @@ from pydantic import (
     TypeAdapter,
 )
 
+from exo.download.huggingface_utils import (
+    filter_repo_objects,
+    get_allow_patterns,
+    get_auth_headers,
+    get_hf_endpoint,
+    get_hf_token,
+)
 from exo.shared.constants import EXO_MODELS_DIR
+from exo.shared.models.model_cards import ModelTask
 from exo.shared.types.common import ModelId
 from exo.shared.types.memory import Memory
 from exo.shared.types.worker.downloads import (
@@ -35,13 +43,6 @@ from exo.shared.types.worker.downloads import (
     RepoFileDownloadProgress,
 )
 from exo.shared.types.worker.shards import ShardMetadata
-from exo.worker.download.huggingface_utils import (
-    filter_repo_objects,
-    get_allow_patterns,
-    get_auth_headers,
-    get_hf_endpoint,
-    get_hf_token,
-)
 
 
 class HuggingFaceAuthenticationError(Exception):
@@ -481,6 +482,11 @@ async def resolve_allow_patterns(shard: ShardMetadata) -> list[str]:
         return ["*"]
 
 
+def is_image_model(shard: ShardMetadata) -> bool:
+    tasks = shard.model_card.tasks
+    return ModelTask.TextToImage in tasks or ModelTask.ImageToImage in tasks
+
+
 async def get_downloaded_size(path: Path) -> int:
     partial_path = path.with_suffix(path.suffix + ".partial")
     if await aios.path.exists(path):
@@ -522,6 +528,15 @@ async def download_shard(
             file_list, allow_patterns=allow_patterns, key=lambda x: x.path
         )
     )
+
+    # For image models, skip root-level safetensors files since weights
+    # are stored in component subdirectories (e.g., transformer/, vae/)
+    if is_image_model(shard):
+        filtered_file_list = [
+            f
+            for f in filtered_file_list
+            if "/" in f.path or not f.path.endswith(".safetensors")
+        ]
     file_progress: dict[str, RepoFileDownloadProgress] = {}
 
     async def on_progress_wrapper(

src/exo/download/impl_shard_downloader.py

@@ -5,13 +5,13 @@ from typing import AsyncIterator, Callable
 
 from loguru import logger
 
+from exo.download.download_utils import RepoDownloadProgress, download_shard
+from exo.download.shard_downloader import ShardDownloader
 from exo.shared.models.model_cards import MODEL_CARDS, ModelCard, ModelId
 from exo.shared.types.worker.shards import (
     PipelineShardMetadata,
     ShardMetadata,
 )
-from exo.worker.download.download_utils import RepoDownloadProgress, download_shard
-from exo.worker.download.shard_downloader import ShardDownloader
 
 
 def exo_shard_downloader(max_parallel_downloads: int = 8) -> ShardDownloader:

src/exo/download/shard_downloader.py

@@ -5,13 +5,13 @@ from datetime import timedelta
 from pathlib import Path
 from typing import AsyncIterator, Callable
 
+from exo.download.download_utils import RepoDownloadProgress
 from exo.shared.models.model_cards import ModelCard, ModelId, ModelTask
 from exo.shared.types.memory import Memory
 from exo.shared.types.worker.shards import (
     PipelineShardMetadata,
     ShardMetadata,
 )
-from exo.worker.download.download_utils import RepoDownloadProgress
 
 
 # TODO: the PipelineShardMetadata getting reinstantiated is a bit messy. Should this be a classmethod?

src/exo/main.py

@@ -1,10 +1,11 @@
 import argparse
+import itertools
 import multiprocessing as mp
 import os
 import resource
 import signal
 from dataclasses import dataclass, field
-from typing import Self
+from typing import Iterator, Self
 
 import anyio
 from anyio.abc import TaskGroup
@@ -12,6 +13,8 @@ from loguru import logger
 from pydantic import PositiveInt
 
 import exo.routing.topics as topics
+from exo.download.coordinator import DownloadCoordinator
+from exo.download.impl_shard_downloader import exo_shard_downloader
 from exo.master.api import API  # TODO: should API be in master?
 from exo.master.main import Master
 from exo.routing.router import Router, get_node_id_keypair
@@ -21,7 +24,6 @@ from exo.shared.logging import logger_cleanup, logger_setup
 from exo.shared.types.common import NodeId, SessionId
 from exo.utils.channels import Receiver, channel
 from exo.utils.pydantic_ext import CamelCaseModel
-from exo.worker.download.impl_shard_downloader import exo_shard_downloader
 from exo.worker.main import Worker
 
 
@@ -29,6 +31,7 @@ from exo.worker.main import Worker
 @dataclass
 class Node:
     router: Router
+    download_coordinator: DownloadCoordinator | None
     worker: Worker | None
     election: Election  # Every node participates in election, as we do want a node to become master even if it isn't a master candidate if no master candidates are present.
     election_result_receiver: Receiver[ElectionResult]
@@ -36,6 +39,7 @@ class Node:
     api: API | None
 
     node_id: NodeId
+    event_index_counter: Iterator[int]
     _tg: TaskGroup = field(init=False, default_factory=anyio.create_task_group)
 
     @classmethod
@@ -49,8 +53,26 @@ class Node:
         await router.register_topic(topics.COMMANDS)
         await router.register_topic(topics.ELECTION_MESSAGES)
         await router.register_topic(topics.CONNECTION_MESSAGES)
+        await router.register_topic(topics.DOWNLOAD_COMMANDS)
 
         logger.info(f"Starting node {node_id}")
+
+        # Create shared event index counter for Worker and DownloadCoordinator
+        event_index_counter = itertools.count()
+
+        # Create DownloadCoordinator (unless --no-downloads)
+        if not args.no_downloads:
+            download_coordinator = DownloadCoordinator(
+                node_id,
+                session_id,
+                exo_shard_downloader(),
+                download_command_receiver=router.receiver(topics.DOWNLOAD_COMMANDS),
+                local_event_sender=router.sender(topics.LOCAL_EVENTS),
+                event_index_counter=event_index_counter,
+            )
+        else:
+            download_coordinator = None
+
         if args.spawn_api:
             api = API(
                 node_id,
@@ -58,6 +80,7 @@ class Node:
                 port=args.api_port,
                 global_event_receiver=router.receiver(topics.GLOBAL_EVENTS),
                 command_sender=router.sender(topics.COMMANDS),
+                download_command_sender=router.sender(topics.DOWNLOAD_COMMANDS),
                 election_receiver=router.receiver(topics.ELECTION_MESSAGES),
             )
         else:
@@ -67,11 +90,12 @@ class Node:
             worker = Worker(
                 node_id,
                 session_id,
-                exo_shard_downloader(),
                 connection_message_receiver=router.receiver(topics.CONNECTION_MESSAGES),
                 global_event_receiver=router.receiver(topics.GLOBAL_EVENTS),
                 local_event_sender=router.sender(topics.LOCAL_EVENTS),
                 command_sender=router.sender(topics.COMMANDS),
+                download_command_sender=router.sender(topics.DOWNLOAD_COMMANDS),
+                event_index_counter=event_index_counter,
             )
         else:
             worker = None
@@ -99,13 +123,25 @@ class Node:
             election_result_sender=er_send,
         )
 
-        return cls(router, worker, election, er_recv, master, api, node_id)
+        return cls(
+            router,
+            download_coordinator,
+            worker,
+            election,
+            er_recv,
+            master,
+            api,
+            node_id,
+            event_index_counter,
+        )
 
     async def run(self):
         async with self._tg as tg:
             signal.signal(signal.SIGINT, lambda _, __: self.shutdown())
             tg.start_soon(self.router.run)
             tg.start_soon(self.election.run)
+            if self.download_coordinator:
+                tg.start_soon(self.download_coordinator.run)
             if self.worker:
                 tg.start_soon(self.worker.run)
             if self.master:
@@ -170,13 +206,27 @@ class Node:
                     )
                 if result.is_new_master:
                     await anyio.sleep(0)
+                    # Fresh counter for new session (buffer expects indices from 0)
+                    self.event_index_counter = itertools.count()
+                    if self.download_coordinator:
+                        self.download_coordinator.shutdown()
+                        self.download_coordinator = DownloadCoordinator(
+                            self.node_id,
+                            result.session_id,
+                            exo_shard_downloader(),
+                            download_command_receiver=self.router.receiver(
+                                topics.DOWNLOAD_COMMANDS
+                            ),
+                            local_event_sender=self.router.sender(topics.LOCAL_EVENTS),
+                            event_index_counter=self.event_index_counter,
+                        )
+                        self._tg.start_soon(self.download_coordinator.run)
                     if self.worker:
                         self.worker.shutdown()
                         # TODO: add profiling etc to resource monitor
                         self.worker = Worker(
                             self.node_id,
                             result.session_id,
-                            exo_shard_downloader(),
                             connection_message_receiver=self.router.receiver(
                                 topics.CONNECTION_MESSAGES
                             ),
@@ -185,6 +235,10 @@ class Node:
                             ),
                             local_event_sender=self.router.sender(topics.LOCAL_EVENTS),
                             command_sender=self.router.sender(topics.COMMANDS),
+                            download_command_sender=self.router.sender(
+                                topics.DOWNLOAD_COMMANDS
+                            ),
+                            event_index_counter=self.event_index_counter,
                         )
                         self._tg.start_soon(self.worker.run)
                     if self.api:
@@ -226,6 +280,7 @@ class Args(CamelCaseModel):
     api_port: PositiveInt = 52415
     tb_only: bool = False
     no_worker: bool = False
+    no_downloads: bool = False
     fast_synch: bool | None = None  # None = auto, True = force on, False = force off
 
     @classmethod
@@ -268,6 +323,11 @@ class Args(CamelCaseModel):
             "--no-worker",
             action="store_true",
         )
+        parser.add_argument(
+            "--no-downloads",
+            action="store_true",
+            help="Disable the download coordinator (node won't download models)",
+        )
         fast_synch_group = parser.add_mutually_exclusive_group()
         fast_synch_group.add_argument(
             "--fast-synch",

src/exo/master/api.py

@@ -44,6 +44,7 @@ from exo.shared.types.api import (
     ChatCompletionResponse,
     CreateInstanceParams,
     CreateInstanceResponse,
+    DeleteDownloadResponse,
     DeleteInstanceResponse,
     ErrorInfo,
     ErrorResponse,
@@ -61,6 +62,8 @@ from exo.shared.types.api import (
     PlaceInstanceParams,
     PlacementPreview,
     PlacementPreviewResponse,
+    StartDownloadParams,
+    StartDownloadResponse,
     StreamingChoiceResponse,
     ToolCall,
 )
@@ -75,12 +78,16 @@ from exo.shared.types.commands import (
     ChatCompletion,
     Command,
     CreateInstance,
+    DeleteDownload,
     DeleteInstance,
+    DownloadCommand,
     ForwarderCommand,
+    ForwarderDownloadCommand,
     ImageEdits,
     ImageGeneration,
     PlaceInstance,
     SendInputChunk,
+    StartDownload,
     TaskFinished,
 )
 from exo.shared.types.common import CommandId, Id, NodeId, SessionId
@@ -156,12 +163,14 @@ class API:
         # Ideally this would be a MasterForwarderEvent but type system says no :(
         global_event_receiver: Receiver[ForwarderEvent],
         command_sender: Sender[ForwarderCommand],
+        download_command_sender: Sender[ForwarderDownloadCommand],
         # This lets us pause the API if an election is running
         election_receiver: Receiver[ElectionMessage],
     ) -> None:
         self.state = State()
         self._event_log: list[Event] = []
         self.command_sender = command_sender
+        self.download_command_sender = download_command_sender
         self.global_event_receiver = global_event_receiver
         self.election_receiver = election_receiver
         self.event_buffer: OrderedBuffer[Event] = OrderedBuffer[Event]()
@@ -260,6 +269,8 @@ class API:
         self.app.get("/images/{image_id}")(self.get_image)
         self.app.get("/state")(lambda: self.state)
         self.app.get("/events")(lambda: self._event_log)
+        self.app.post("/download/start")(self.start_download)
+        self.app.delete("/download/{node_id}/{model_id:path}")(self.delete_download)
 
     async def place_instance(self, payload: PlaceInstanceParams):
         command = PlaceInstance(
@@ -345,14 +356,9 @@ class API:
     ) -> PlacementPreviewResponse:
         seen: set[tuple[ModelId, Sharding, InstanceMeta, int]] = set()
         previews: list[PlacementPreview] = []
+        required_nodes = set(node_ids) if node_ids else None
 
-        # Create filtered topology if node_ids specified
-        if node_ids and len(node_ids) > 0:
-            topology = self.state.topology.get_subgraph_from_nodes(node_ids)
-        else:
-            topology = self.state.topology
-
-        if len(list(topology.list_nodes())) == 0:
+        if len(list(self.state.topology.list_nodes())) == 0:
             return PlacementPreviewResponse(previews=[])
 
         cards = [card for card in MODEL_CARDS.values() if card.model_id == model_id]
@@ -365,7 +371,9 @@ class API:
                 instance_combinations.extend(
                     [
                         (sharding, instance_meta, i)
-                        for i in range(1, len(list(topology.list_nodes())) + 1)
+                        for i in range(
+                            1, len(list(self.state.topology.list_nodes())) + 1
+                        )
                     ]
                 )
         # TODO: PDD
@@ -383,8 +391,9 @@ class API:
                         ),
                         node_memory=self.state.node_memory,
                         node_network=self.state.node_network,
-                        topology=topology,
+                        topology=self.state.topology,
                         current_instances=self.state.instances,
+                        required_nodes=required_nodes,
                     )
                 except ValueError as exc:
                     if (model_card.model_id, sharding, instance_meta, 0) not in seen:
@@ -423,14 +432,16 @@ class API:
 
                 instance = new_instances[0]
                 shard_assignments = instance.shard_assignments
-                node_ids = list(shard_assignments.node_to_runner.keys())
+                placement_node_ids = list(shard_assignments.node_to_runner.keys())
 
                 memory_delta_by_node: dict[str, int] = {}
-                if node_ids:
+                if placement_node_ids:
                     total_bytes = model_card.storage_size.in_bytes
-                    per_node = total_bytes // len(node_ids)
-                    remainder = total_bytes % len(node_ids)
-                    for index, node_id in enumerate(sorted(node_ids, key=str)):
+                    per_node = total_bytes // len(placement_node_ids)
+                    remainder = total_bytes % len(placement_node_ids)
+                    for index, node_id in enumerate(
+                        sorted(placement_node_ids, key=str)
+                    ):
                         extra = 1 if index < remainder else 0
                         memory_delta_by_node[str(node_id)] = per_node + extra
 
@@ -438,7 +449,7 @@ class API:
                     model_card.model_id,
                     sharding,
                     instance_meta,
-                    len(node_ids),
+                    len(placement_node_ids),
                 ) not in seen:
                     previews.append(
                         PlacementPreview(
@@ -450,7 +461,14 @@ class API:
                             error=None,
                         )
                     )
-                seen.add((model_card.model_id, sharding, instance_meta, len(node_ids)))
+                seen.add(
+                    (
+                        model_card.model_id,
+                        sharding,
+                        instance_meta,
+                        len(placement_node_ids),
+                    )
+                )
 
         return PlacementPreviewResponse(previews=previews)
 
@@ -1292,3 +1310,28 @@ class API:
         await self.command_sender.send(
             ForwarderCommand(origin=self.node_id, command=command)
         )
+
+    async def _send_download(self, command: DownloadCommand):
+        await self.download_command_sender.send(
+            ForwarderDownloadCommand(origin=self.node_id, command=command)
+        )
+
+    async def start_download(
+        self, payload: StartDownloadParams
+    ) -> StartDownloadResponse:
+        command = StartDownload(
+            target_node_id=payload.target_node_id,
+            shard_metadata=payload.shard_metadata,
+        )
+        await self._send_download(command)
+        return StartDownloadResponse(command_id=command.command_id)
+
+    async def delete_download(
+        self, node_id: NodeId, model_id: ModelId
+    ) -> DeleteDownloadResponse:
+        command = DeleteDownload(
+            target_node_id=node_id,
+            model_id=ModelId(model_id),
+        )
+        await self._send_download(command)
+        return DeleteDownloadResponse(command_id=command.command_id)

src/exo/master/placement.py

@@ -35,7 +35,7 @@ from exo.shared.types.worker.shards import Sharding
 
 def random_ephemeral_port() -> int:
     port = random.randint(49153, 65535)
-    return port - 1 if port <= 52415 else 52414
+    return port - 1 if port <= 52415 else port
 
 
 def add_instance_to_placements(
@@ -54,9 +54,18 @@ def place_instance(
     current_instances: Mapping[InstanceId, Instance],
     node_memory: Mapping[NodeId, MemoryUsage],
     node_network: Mapping[NodeId, NodeNetworkInfo],
+    required_nodes: set[NodeId] | None = None,
 ) -> dict[InstanceId, Instance]:
     cycles = topology.get_cycles()
     candidate_cycles = list(filter(lambda it: len(it) >= command.min_nodes, cycles))
+
+    # Filter to cycles containing all required nodes (subset matching)
+    if required_nodes:
+        candidate_cycles = [
+            cycle
+            for cycle in candidate_cycles
+            if required_nodes.issubset(cycle.node_ids)
+        ]
     cycles_with_sufficient_memory = filter_cycles_by_memory(
         candidate_cycles, node_memory, command.model_card.storage_size
     )

src/exo/routing/topics.py

@@ -3,7 +3,7 @@ from enum import Enum
 
 from exo.routing.connection_message import ConnectionMessage
 from exo.shared.election import ElectionMessage
-from exo.shared.types.commands import ForwarderCommand
+from exo.shared.types.commands import ForwarderCommand, ForwarderDownloadCommand
 from exo.shared.types.events import (
     ForwarderEvent,
 )
@@ -45,3 +45,6 @@ ELECTION_MESSAGES = TypedTopic(
 CONNECTION_MESSAGES = TypedTopic(
     "connection_messages", PublishPolicy.Never, ConnectionMessage
 )
+DOWNLOAD_COMMANDS = TypedTopic(
+    "download_commands", PublishPolicy.Always, ForwarderDownloadCommand
+)

src/exo/shared/models/model_cards.py

@@ -40,6 +40,7 @@ class ModelCard(CamelCaseModel):
     supports_tensor: bool
     tasks: list[ModelTask]
     components: list[ComponentInfo] | None = None
+    quantization: int | None = None
 
     @field_validator("tasks", mode="before")
     @classmethod
@@ -413,7 +414,7 @@ MODEL_CARDS: dict[str, ModelCard] = {
     ),
 }
 
-_IMAGE_MODEL_CARDS: dict[str, ModelCard] = {
+_IMAGE_BASE_MODEL_CARDS: dict[str, ModelCard] = {
     "flux1-schnell": ModelCard(
         model_id=ModelId("black-forest-labs/FLUX.1-schnell"),
         storage_size=Memory.from_bytes(23782357120 + 9524621312),
@@ -428,7 +429,7 @@ _IMAGE_MODEL_CARDS: dict[str, ModelCard] = {
                 storage_size=Memory.from_kb(0),
                 n_layers=12,
                 can_shard=False,
-                safetensors_index_filename=None,  # Single file
+                safetensors_index_filename=None,
             ),
             ComponentInfo(
                 component_name="text_encoder_2",
@@ -442,7 +443,7 @@ _IMAGE_MODEL_CARDS: dict[str, ModelCard] = {
                 component_name="transformer",
                 component_path="transformer/",
                 storage_size=Memory.from_bytes(23782357120),
-                n_layers=57,  # 19 transformer_blocks + 38 single_transformer_blocks
+                n_layers=57,
                 can_shard=True,
                 safetensors_index_filename="diffusion_pytorch_model.safetensors.index.json",
             ),
@@ -458,7 +459,7 @@ _IMAGE_MODEL_CARDS: dict[str, ModelCard] = {
     ),
     "flux1-dev": ModelCard(
         model_id=ModelId("black-forest-labs/FLUX.1-dev"),
-        storage_size=Memory.from_bytes(23782357120 + 9524621312),
+        storage_size=Memory.from_bytes(23802816640 + 9524621312),
         n_layers=57,
         hidden_size=1,
         supports_tensor=False,
@@ -470,7 +471,7 @@ _IMAGE_MODEL_CARDS: dict[str, ModelCard] = {
                 storage_size=Memory.from_kb(0),
                 n_layers=12,
                 can_shard=False,
-                safetensors_index_filename=None,  # Single file
+                safetensors_index_filename=None,
             ),
             ComponentInfo(
                 component_name="text_encoder_2",
@@ -484,7 +485,49 @@ _IMAGE_MODEL_CARDS: dict[str, ModelCard] = {
                 component_name="transformer",
                 component_path="transformer/",
                 storage_size=Memory.from_bytes(23802816640),
-                n_layers=57,  # 19 transformer_blocks + 38 single_transformer_blocks
+                n_layers=57,
+                can_shard=True,
+                safetensors_index_filename="diffusion_pytorch_model.safetensors.index.json",
+            ),
+            ComponentInfo(
+                component_name="vae",
+                component_path="vae/",
+                storage_size=Memory.from_kb(0),
+                n_layers=None,
+                can_shard=False,
+                safetensors_index_filename=None,
+            ),
+        ],
+    ),
+    "flux1-krea-dev": ModelCard(
+        model_id=ModelId("black-forest-labs/FLUX.1-Krea-dev"),
+        storage_size=Memory.from_bytes(23802816640 + 9524621312),  # Same as dev
+        n_layers=57,
+        hidden_size=1,
+        supports_tensor=False,
+        tasks=[ModelTask.TextToImage],
+        components=[
+            ComponentInfo(
+                component_name="text_encoder",
+                component_path="text_encoder/",
+                storage_size=Memory.from_kb(0),
+                n_layers=12,
+                can_shard=False,
+                safetensors_index_filename=None,
+            ),
+            ComponentInfo(
+                component_name="text_encoder_2",
+                component_path="text_encoder_2/",
+                storage_size=Memory.from_bytes(9524621312),
+                n_layers=24,
+                can_shard=False,
+                safetensors_index_filename="model.safetensors.index.json",
+            ),
+            ComponentInfo(
+                component_name="transformer",
+                component_path="transformer/",
+                storage_size=Memory.from_bytes(23802816640),
+                n_layers=57,
                 can_shard=True,
                 safetensors_index_filename="diffusion_pytorch_model.safetensors.index.json",
             ),
@@ -501,7 +544,7 @@ _IMAGE_MODEL_CARDS: dict[str, ModelCard] = {
     "qwen-image": ModelCard(
         model_id=ModelId("Qwen/Qwen-Image"),
         storage_size=Memory.from_bytes(16584333312 + 40860802176),
-        n_layers=60,  # Qwen has 60 transformer blocks (all joint-style)
+        n_layers=60,
         hidden_size=1,
         supports_tensor=False,
         tasks=[ModelTask.TextToImage],
@@ -509,10 +552,10 @@ _IMAGE_MODEL_CARDS: dict[str, ModelCard] = {
             ComponentInfo(
                 component_name="text_encoder",
                 component_path="text_encoder/",
-                storage_size=Memory.from_kb(16584333312),
+                storage_size=Memory.from_bytes(16584333312),
                 n_layers=12,
                 can_shard=False,
-                safetensors_index_filename=None,  # Single file
+                safetensors_index_filename=None,
             ),
             ComponentInfo(
                 component_name="transformer",
@@ -535,7 +578,7 @@ _IMAGE_MODEL_CARDS: dict[str, ModelCard] = {
     "qwen-image-edit-2509": ModelCard(
         model_id=ModelId("Qwen/Qwen-Image-Edit-2509"),
         storage_size=Memory.from_bytes(16584333312 + 40860802176),
-        n_layers=60,  # Qwen has 60 transformer blocks (all joint-style)
+        n_layers=60,
         hidden_size=1,
         supports_tensor=False,
         tasks=[ModelTask.ImageToImage],
@@ -543,10 +586,10 @@ _IMAGE_MODEL_CARDS: dict[str, ModelCard] = {
             ComponentInfo(
                 component_name="text_encoder",
                 component_path="text_encoder/",
-                storage_size=Memory.from_kb(16584333312),
+                storage_size=Memory.from_bytes(16584333312),
                 n_layers=12,
                 can_shard=False,
-                safetensors_index_filename=None,  # Single file
+                safetensors_index_filename=None,
             ),
             ComponentInfo(
                 component_name="transformer",
@@ -568,6 +611,93 @@ _IMAGE_MODEL_CARDS: dict[str, ModelCard] = {
     ),
 }
 
+
+def _create_image_model_quant_variants(
+    base_name: str,
+    base_card: ModelCard,
+) -> dict[str, ModelCard]:
+    """Create quantized variants of an image model card.
+
+    Only the transformer component is quantized; text encoders stay at bf16.
+    Sizes are calculated exactly from the base card's component sizes.
+    """
+    if base_card.components is None:
+        raise ValueError(f"Image model {base_name} must have components defined")
+
+    quantizations = [8, 6, 5, 4, 3]
+
+    num_transformer_bytes = next(
+        c.storage_size.in_bytes
+        for c in base_card.components
+        if c.component_name == "transformer"
+    )
+
+    transformer_bytes = Memory.from_bytes(num_transformer_bytes)
+
+    remaining_bytes = Memory.from_bytes(
+        sum(
+            c.storage_size.in_bytes
+            for c in base_card.components
+            if c.component_name != "transformer"
+        )
+    )
+
+    def with_transformer_size(new_size: Memory) -> list[ComponentInfo]:
+        assert base_card.components is not None
+        return [
+            ComponentInfo(
+                component_name=c.component_name,
+                component_path=c.component_path,
+                storage_size=new_size
+                if c.component_name == "transformer"
+                else c.storage_size,
+                n_layers=c.n_layers,
+                can_shard=c.can_shard,
+                safetensors_index_filename=c.safetensors_index_filename,
+            )
+            for c in base_card.components
+        ]
+
+    variants = {
+        base_name: ModelCard(
+            model_id=base_card.model_id,
+            storage_size=transformer_bytes + remaining_bytes,
+            n_layers=base_card.n_layers,
+            hidden_size=base_card.hidden_size,
+            supports_tensor=base_card.supports_tensor,
+            tasks=base_card.tasks,
+            components=with_transformer_size(transformer_bytes),
+            quantization=None,
+        )
+    }
+
+    for quant in quantizations:
+        quant_transformer_bytes = Memory.from_bytes(
+            (num_transformer_bytes * quant) // 16
+        )
+        total_bytes = remaining_bytes + quant_transformer_bytes
+
+        model_id = base_card.model_id + f"-{quant}bit"
+
+        variants[f"{base_name}-{quant}bit"] = ModelCard(
+            model_id=ModelId(model_id),
+            storage_size=total_bytes,
+            n_layers=base_card.n_layers,
+            hidden_size=base_card.hidden_size,
+            supports_tensor=base_card.supports_tensor,
+            tasks=base_card.tasks,
+            components=with_transformer_size(quant_transformer_bytes),
+            quantization=quant,
+        )
+
+    return variants
+
+
+_image_model_cards: dict[str, ModelCard] = {}
+for _base_name, _base_card in _IMAGE_BASE_MODEL_CARDS.items():
+    _image_model_cards |= _create_image_model_quant_variants(_base_name, _base_card)
+_IMAGE_MODEL_CARDS = _image_model_cards
+
 if EXO_ENABLE_IMAGE_MODELS:
     MODEL_CARDS.update(_IMAGE_MODEL_CARDS)
 
@@ -621,7 +751,7 @@ class ConfigData(BaseModel):
 
 async def get_config_data(model_id: ModelId) -> ConfigData:
     """Downloads and parses config.json for a model."""
-    from exo.worker.download.download_utils import (
+    from exo.download.download_utils import (
         download_file_with_retry,
         ensure_models_dir,
     )
@@ -643,11 +773,11 @@ async def get_config_data(model_id: ModelId) -> ConfigData:
 
 async def get_safetensors_size(model_id: ModelId) -> Memory:
     """Gets model size from safetensors index or falls back to HF API."""
-    from exo.shared.types.worker.downloads import ModelSafetensorsIndex
-    from exo.worker.download.download_utils import (
+    from exo.download.download_utils import (
         download_file_with_retry,
         ensure_models_dir,
     )
+    from exo.shared.types.worker.downloads import ModelSafetensorsIndex
 
     target_dir = (await ensure_models_dir()) / model_id.normalize()
     await aios.makedirs(target_dir, exist_ok=True)

src/exo/shared/topology.py

@@ -248,8 +248,8 @@ class Topology:
     ) -> list[list[NodeId]]:
         """
         Find cycles in the Thunderbolt topology where all nodes have TB bridge enabled.
-        Only returns cycles with >2 nodes (3+ machines in a loop), as cycles with
-        2 or fewer nodes don't cause the broadcast storm problem.
+        Only returns cycles with >=2 nodes (2+ machines in a loop), as
+        1 node doesn't cause the broadcast storm problem.
         """
         enabled_nodes = {
             node_id
@@ -257,7 +257,7 @@ class Topology:
             if status.enabled
         }
 
-        if len(enabled_nodes) < 3:
+        if len(enabled_nodes) < 2:
             return []
 
         thunderbolt_ips = _get_ips_with_interface_type(
@@ -288,7 +288,7 @@ class Topology:
         return [
             [graph[idx] for idx in cycle]
             for cycle in rx.simple_cycles(graph)
-            if len(cycle) > 2
+            if len(cycle) >= 2
         ]
 
 

src/exo/shared/types/api.py

@@ -7,10 +7,11 @@ from pydantic import BaseModel, Field, field_validator
 from pydantic_core import PydanticUseDefault
 
 from exo.shared.models.model_cards import ModelCard, ModelId
-from exo.shared.types.common import CommandId
+from exo.shared.types.common import CommandId, NodeId
 from exo.shared.types.memory import Memory
 from exo.shared.types.worker.instances import Instance, InstanceId, InstanceMeta
-from exo.shared.types.worker.shards import Sharding
+from exo.shared.types.worker.shards import Sharding, ShardMetadata
+from exo.utils.pydantic_ext import CamelCaseModel
 
 FinishReason = Literal[
     "stop", "length", "tool_calls", "content_filter", "function_call", "error"
@@ -352,3 +353,16 @@ class ImageListItem(BaseModel, frozen=True):
 
 class ImageListResponse(BaseModel, frozen=True):
     data: list[ImageListItem]
+
+
+class StartDownloadParams(CamelCaseModel):
+    target_node_id: NodeId
+    shard_metadata: ShardMetadata
+
+
+class StartDownloadResponse(CamelCaseModel):
+    command_id: CommandId
+
+
+class DeleteDownloadResponse(CamelCaseModel):
+    command_id: CommandId

src/exo/shared/types/commands.py

@@ -1,6 +1,6 @@
 from pydantic import Field
 
-from exo.shared.models.model_cards import ModelCard
+from exo.shared.models.model_cards import ModelCard, ModelId
 from exo.shared.types.api import (
     ChatCompletionTaskParams,
     ImageEditsInternalParams,
@@ -9,7 +9,7 @@ from exo.shared.types.api import (
 from exo.shared.types.chunks import InputImageChunk
 from exo.shared.types.common import CommandId, NodeId
 from exo.shared.types.worker.instances import Instance, InstanceId, InstanceMeta
-from exo.shared.types.worker.shards import Sharding
+from exo.shared.types.worker.shards import Sharding, ShardMetadata
 from exo.utils.pydantic_ext import CamelCaseModel, TaggedModel
 
 
@@ -62,6 +62,19 @@ class RequestEventLog(BaseCommand):
     since_idx: int
 
 
+class StartDownload(BaseCommand):
+    target_node_id: NodeId
+    shard_metadata: ShardMetadata
+
+
+class DeleteDownload(BaseCommand):
+    target_node_id: NodeId
+    model_id: ModelId
+
+
+DownloadCommand = StartDownload | DeleteDownload
+
+
 Command = (
     TestCommand
     | RequestEventLog
@@ -79,3 +92,8 @@ Command = (
 class ForwarderCommand(CamelCaseModel):
     origin: NodeId
     command: Command
+
+
+class ForwarderDownloadCommand(CamelCaseModel):
+    origin: NodeId
+    command: DownloadCommand

src/exo/utils/keyed_backoff.py

@@ -0,0 +1,32 @@
+import time
+from typing import Generic, TypeVar
+
+K = TypeVar("K")
+
+
+class KeyedBackoff(Generic[K]):
+    """Tracks exponential backoff state per key."""
+
+    def __init__(self, base: float = 0.5, cap: float = 10.0):
+        self._base = base
+        self._cap = cap
+        self._attempts: dict[K, int] = {}
+        self._last_time: dict[K, float] = {}
+
+    def should_proceed(self, key: K) -> bool:
+        """Returns True if enough time has elapsed since last attempt."""
+        now = time.monotonic()
+        last = self._last_time.get(key, 0.0)
+        attempts = self._attempts.get(key, 0)
+        delay = min(self._cap, self._base * (2.0**attempts))
+        return now - last >= delay
+
+    def record_attempt(self, key: K) -> None:
+        """Record that an attempt was made for this key."""
+        self._last_time[key] = time.monotonic()
+        self._attempts[key] = self._attempts.get(key, 0) + 1
+
+    def reset(self, key: K) -> None:
+        """Reset backoff state for a key (e.g., on success)."""
+        self._attempts.pop(key, None)
+        self._last_time.pop(key, None)

src/exo/worker/engines/image/distributed_model.py

@@ -6,10 +6,10 @@ import mlx.core as mx
 from mflux.models.common.config.config import Config
 from PIL import Image
 
+from exo.download.download_utils import build_model_path
 from exo.shared.types.api import AdvancedImageParams
 from exo.shared.types.worker.instances import BoundInstance
 from exo.shared.types.worker.shards import PipelineShardMetadata
-from exo.worker.download.download_utils import build_model_path
 from exo.worker.engines.image.config import ImageModelConfig
 from exo.worker.engines.image.models import (
     create_adapter_for_model,
@@ -71,8 +71,10 @@ class DistributedImageModel:
     def from_bound_instance(
         cls, bound_instance: BoundInstance
     ) -> "DistributedImageModel":
-        model_id = bound_instance.bound_shard.model_card.model_id
+        model_card = bound_instance.bound_shard.model_card
+        model_id = model_card.model_id
         model_path = build_model_path(model_id)
+        quantize = model_card.quantization
 
         shard_metadata = bound_instance.bound_shard
         if not isinstance(shard_metadata, PipelineShardMetadata):
@@ -93,6 +95,7 @@ class DistributedImageModel:
             local_path=model_path,
             shard_metadata=shard_metadata,
             group=group,
+            quantize=quantize,
         )
 
     def get_steps_for_quality(self, quality: Literal["low", "medium", "high"]) -> int:
@@ -140,6 +143,7 @@ class DistributedImageModel:
             width=width,
             image_path=image_path,
             model_config=self._adapter.model.model_config,  # pyright: ignore[reportAny]
+            guidance=guidance_override if guidance_override is not None else 4.0,
         )
 
         num_sync_steps = self._config.get_num_sync_steps(steps)

src/exo/worker/engines/image/models/__init__.py

@@ -33,6 +33,7 @@ _ADAPTER_REGISTRY: dict[str, AdapterFactory] = {
 # Config registry: maps model ID patterns to configs
 _CONFIG_REGISTRY: dict[str, ImageModelConfig] = {
     "flux.1-schnell": FLUX_SCHNELL_CONFIG,
+    "flux.1-krea-dev": FLUX_DEV_CONFIG,  # Must come before "flux.1-dev" for pattern matching
     "flux.1-dev": FLUX_DEV_CONFIG,
     "qwen-image-edit": QWEN_IMAGE_EDIT_CONFIG,  # Must come before "qwen-image" for pattern matching
     "qwen-image": QWEN_IMAGE_CONFIG,

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

@@ -41,6 +41,7 @@ import mlx.nn as nn
 from mlx_lm.utils import load_model
 from pydantic import RootModel
 
+from exo.download.download_utils import build_model_path
 from exo.shared.types.api import ChatCompletionMessageText
 from exo.shared.types.common import Host
 from exo.shared.types.memory import Memory
@@ -55,7 +56,6 @@ from exo.shared.types.worker.shards import (
     ShardMetadata,
     TensorShardMetadata,
 )
-from exo.worker.download.download_utils import build_model_path
 from exo.worker.engines.mlx import Model
 from exo.worker.engines.mlx.auto_parallel import (
     TimeoutCallback,

src/exo/worker/main.py

@@ -1,8 +1,9 @@
 from datetime import datetime, timezone
 from random import random
+from typing import Iterator
 
 import anyio
-from anyio import CancelScope, create_task_group, current_time, fail_after
+from anyio import CancelScope, create_task_group, fail_after
 from anyio.abc import TaskGroup
 from loguru import logger
 
@@ -10,7 +11,12 @@ from exo.routing.connection_message import ConnectionMessage, ConnectionMessageT
 from exo.shared.apply import apply
 from exo.shared.models.model_cards import ModelId
 from exo.shared.types.api import ImageEditsInternalParams
-from exo.shared.types.commands import ForwarderCommand, RequestEventLog
+from exo.shared.types.commands import (
+    ForwarderCommand,
+    ForwarderDownloadCommand,
+    RequestEventLog,
+    StartDownload,
+)
 from exo.shared.types.common import CommandId, NodeId, SessionId
 from exo.shared.types.events import (
     Event,
@@ -18,7 +24,6 @@ from exo.shared.types.events import (
     ForwarderEvent,
     IndexedEvent,
     InputChunkReceived,
-    NodeDownloadProgress,
     NodeGatheredInfo,
     TaskCreated,
     TaskStatusUpdated,
@@ -36,23 +41,12 @@ from exo.shared.types.tasks import (
     TaskStatus,
 )
 from exo.shared.types.topology import Connection, SocketConnection
-from exo.shared.types.worker.downloads import (
-    DownloadCompleted,
-    DownloadFailed,
-    DownloadOngoing,
-    DownloadPending,
-    DownloadProgress,
-)
 from exo.shared.types.worker.runners import RunnerId
-from exo.shared.types.worker.shards import ShardMetadata
 from exo.utils.channels import Receiver, Sender, channel
 from exo.utils.event_buffer import OrderedBuffer
 from exo.utils.info_gatherer.info_gatherer import GatheredInfo, InfoGatherer
 from exo.utils.info_gatherer.net_profile import check_reachable
-from exo.worker.download.download_utils import (
-    map_repo_download_progress_to_download_progress_data,
-)
-from exo.worker.download.shard_downloader import RepoDownloadProgress, ShardDownloader
+from exo.utils.keyed_backoff import KeyedBackoff
 from exo.worker.plan import plan
 from exo.worker.runner.runner_supervisor import RunnerSupervisor
 
@@ -62,7 +56,6 @@ class Worker:
         self,
         node_id: NodeId,
         session_id: SessionId,
-        shard_downloader: ShardDownloader,
         *,
         connection_message_receiver: Receiver[ConnectionMessage],
         global_event_receiver: Receiver[ForwarderEvent],
@@ -70,23 +63,22 @@ class Worker:
         # This is for requesting updates. It doesn't need to be a general command sender right now,
         # but I think it's the correct way to be thinking about commands
         command_sender: Sender[ForwarderCommand],
+        download_command_sender: Sender[ForwarderDownloadCommand],
+        event_index_counter: Iterator[int],
     ):
         self.node_id: NodeId = node_id
         self.session_id: SessionId = session_id
 
-        self.shard_downloader: ShardDownloader = shard_downloader
-        self._pending_downloads: dict[RunnerId, ShardMetadata] = {}
-
         self.global_event_receiver = global_event_receiver
         self.local_event_sender = local_event_sender
-        self.local_event_index = 0
+        self.event_index_counter = event_index_counter
         self.command_sender = command_sender
+        self.download_command_sender = download_command_sender
         self.connection_message_receiver = connection_message_receiver
         self.event_buffer = OrderedBuffer[Event]()
         self.out_for_delivery: dict[EventId, ForwarderEvent] = {}
 
         self.state: State = State()
-        self.download_status: dict[ModelId, DownloadProgress] = {}
         self.runners: dict[RunnerId, RunnerSupervisor] = {}
         self._tg: TaskGroup = create_task_group()
 
@@ -101,6 +93,8 @@ class Worker:
         self.input_chunk_buffer: dict[CommandId, dict[int, str]] = {}
         self.input_chunk_counts: dict[CommandId, int] = {}
 
+        self._download_backoff: KeyedBackoff[ModelId] = KeyedBackoff(base=0.5, cap=10.0)
+
     async def run(self):
         logger.info("Starting Worker")
 
@@ -111,7 +105,6 @@ class Worker:
             tg.start_soon(info_gatherer.run)
             tg.start_soon(self._forward_info, info_recv)
             tg.start_soon(self.plan_step)
-            tg.start_soon(self._emit_existing_download_progress)
             tg.start_soon(self._connection_message_event_writer)
             tg.start_soon(self._resend_out_for_delivery)
             tg.start_soon(self._event_applier)
@@ -121,6 +114,7 @@ class Worker:
         # Actual shutdown code - waits for all tasks to complete before executing.
         self.local_event_sender.close()
         self.command_sender.close()
+        self.download_command_sender.close()
         for runner in self.runners.values():
             runner.shutdown()
 
@@ -179,11 +173,9 @@ class Worker:
     async def plan_step(self):
         while True:
             await anyio.sleep(0.1)
-            # 3. based on the updated state, we plan & execute an operation.
             task: Task | None = plan(
                 self.node_id,
                 self.runners,
-                self.download_status,
                 self.state.downloads,
                 self.state.instances,
                 self.state.runners,
@@ -207,42 +199,26 @@ class Worker:
                         )
                     )
                 case DownloadModel(shard_metadata=shard):
-                    if shard.model_card.model_id not in self.download_status:
-                        progress = DownloadPending(
-                            shard_metadata=shard, node_id=self.node_id
-                        )
-                        self.download_status[shard.model_card.model_id] = progress
-                        await self.event_sender.send(
-                            NodeDownloadProgress(download_progress=progress)
-                        )
-                    initial_progress = (
-                        await self.shard_downloader.get_shard_download_status_for_shard(
-                            shard
+                    model_id = shard.model_card.model_id
+                    if not self._download_backoff.should_proceed(model_id):
+                        continue
+
+                    self._download_backoff.record_attempt(model_id)
+
+                    await self.download_command_sender.send(
+                        ForwarderDownloadCommand(
+                            origin=self.node_id,
+                            command=StartDownload(
+                                target_node_id=self.node_id,
+                                shard_metadata=shard,
+                            ),
                         )
                     )
-                    if initial_progress.status == "complete":
-                        progress = DownloadCompleted(
-                            shard_metadata=shard,
-                            node_id=self.node_id,
-                            total_bytes=initial_progress.total_bytes,
+                    await self.event_sender.send(
+                        TaskStatusUpdated(
+                            task_id=task.task_id, task_status=TaskStatus.Running
                         )
-                        self.download_status[shard.model_card.model_id] = progress
-                        await self.event_sender.send(
-                            NodeDownloadProgress(download_progress=progress)
-                        )
-                        await self.event_sender.send(
-                            TaskStatusUpdated(
-                                task_id=task.task_id,
-                                task_status=TaskStatus.Complete,
-                            )
-                        )
-                    else:
-                        await self.event_sender.send(
-                            TaskStatusUpdated(
-                                task_id=task.task_id, task_status=TaskStatus.Running
-                            )
-                        )
-                        self._handle_shard_download_process(task, initial_progress)
+                    )
                 case Shutdown(runner_id=runner_id):
                     try:
                         with fail_after(3):
@@ -387,104 +363,17 @@ class Worker:
         self._tg.start_soon(runner.run)
         return runner
 
-    def _handle_shard_download_process(
-        self,
-        task: DownloadModel,
-        initial_progress: RepoDownloadProgress,
-    ):
-        """Manages the shard download process with progress tracking."""
-        status = DownloadOngoing(
-            node_id=self.node_id,
-            shard_metadata=task.shard_metadata,
-            download_progress=map_repo_download_progress_to_download_progress_data(
-                initial_progress
-            ),
-        )
-        self.download_status[task.shard_metadata.model_card.model_id] = status
-        self.event_sender.send_nowait(NodeDownloadProgress(download_progress=status))
-
-        last_progress_time = 0.0
-        throttle_interval_secs = 1.0
-
-        async def download_progress_callback(
-            shard: ShardMetadata, progress: RepoDownloadProgress
-        ) -> None:
-            nonlocal self
-            nonlocal last_progress_time
-            if progress.status == "complete":
-                status = DownloadCompleted(
-                    shard_metadata=shard,
-                    node_id=self.node_id,
-                    total_bytes=progress.total_bytes,
-                )
-                self.download_status[shard.model_card.model_id] = status
-                await self.event_sender.send(
-                    NodeDownloadProgress(download_progress=status)
-                )
-                await self.event_sender.send(
-                    TaskStatusUpdated(
-                        task_id=task.task_id, task_status=TaskStatus.Complete
-                    )
-                )
-            elif (
-                progress.status == "in_progress"
-                and current_time() - last_progress_time > throttle_interval_secs
-            ):
-                status = DownloadOngoing(
-                    node_id=self.node_id,
-                    shard_metadata=shard,
-                    download_progress=map_repo_download_progress_to_download_progress_data(
-                        progress
-                    ),
-                )
-                self.download_status[shard.model_card.model_id] = status
-                await self.event_sender.send(
-                    NodeDownloadProgress(download_progress=status)
-                )
-                last_progress_time = current_time()
-
-        self.shard_downloader.on_progress(download_progress_callback)
-
-        async def download_with_error_handling() -> None:
-            try:
-                await self.shard_downloader.ensure_shard(task.shard_metadata)
-            except Exception as e:
-                error_message = str(e)
-                logger.error(
-                    f"Download failed for {task.shard_metadata.model_card.model_id}: {error_message}"
-                )
-                failed_status = DownloadFailed(
-                    node_id=self.node_id,
-                    shard_metadata=task.shard_metadata,
-                    error_message=error_message,
-                )
-                self.download_status[task.shard_metadata.model_card.model_id] = (
-                    failed_status
-                )
-                await self.event_sender.send(
-                    NodeDownloadProgress(download_progress=failed_status)
-                )
-                await self.event_sender.send(
-                    TaskStatusUpdated(
-                        task_id=task.task_id, task_status=TaskStatus.Failed
-                    )
-                )
-
-        self._tg.start_soon(download_with_error_handling)
-
     async def _forward_events(self) -> None:
         with self.event_receiver as events:
             async for event in events:
+                idx = next(self.event_index_counter)
                 fe = ForwarderEvent(
-                    origin_idx=self.local_event_index,
+                    origin_idx=idx,
                     origin=self.node_id,
                     session=self.session_id,
                     event=event,
                 )
-                logger.debug(
-                    f"Worker published event {self.local_event_index}: {str(event)[:100]}"
-                )
-                self.local_event_index += 1
+                logger.debug(f"Worker published event {idx}: {str(event)[:100]}")
                 await self.local_event_sender.send(fe)
                 self.out_for_delivery[event.event_id] = fe
 
@@ -532,42 +421,3 @@ class Worker:
                     await self.event_sender.send(TopologyEdgeDeleted(conn=conn))
 
             await anyio.sleep(10)
-
-    async def _emit_existing_download_progress(self) -> None:
-        try:
-            while True:
-                logger.debug("Fetching and emitting existing download progress...")
-                async for (
-                    _,
-                    progress,
-                ) in self.shard_downloader.get_shard_download_status():
-                    if progress.status == "complete":
-                        status = DownloadCompleted(
-                            node_id=self.node_id,
-                            shard_metadata=progress.shard,
-                            total_bytes=progress.total_bytes,
-                        )
-                    elif progress.status in ["in_progress", "not_started"]:
-                        if progress.downloaded_bytes_this_session.in_bytes == 0:
-                            status = DownloadPending(
-                                node_id=self.node_id, shard_metadata=progress.shard
-                            )
-                        else:
-                            status = DownloadOngoing(
-                                node_id=self.node_id,
-                                shard_metadata=progress.shard,
-                                download_progress=map_repo_download_progress_to_download_progress_data(
-                                    progress
-                                ),
-                            )
-                    else:
-                        continue
-
-                    self.download_status[progress.shard.model_card.model_id] = status
-                    await self.event_sender.send(
-                        NodeDownloadProgress(download_progress=status)
-                    )
-                logger.debug("Done emitting existing download progress.")
-                await anyio.sleep(5 * 60)  # 5 minutes
-        except Exception as e:
-            logger.error(f"Error emitting existing download progress: {e}")

src/exo/worker/plan.py

@@ -2,7 +2,6 @@
 
 from collections.abc import Mapping, Sequence
 
-from exo.shared.models.model_cards import ModelId
 from exo.shared.types.common import CommandId, NodeId
 from exo.shared.types.tasks import (
     ChatCompletion,
@@ -45,9 +44,6 @@ def plan(
     node_id: NodeId,
     # Runners is expected to be FRESH and so should not come from state
     runners: Mapping[RunnerId, RunnerSupervisor],
-    # DL_status is expected to be FRESH and so should not come from state
-    download_status: Mapping[ModelId, DownloadProgress],
-    # gdls is not expected to be fresh
     global_download_status: Mapping[NodeId, Sequence[DownloadProgress]],
     instances: Mapping[InstanceId, Instance],
     all_runners: Mapping[RunnerId, RunnerStatus],  # all global
@@ -59,7 +55,7 @@ def plan(
     return (
         _kill_runner(runners, all_runners, instances)
         or _create_runner(node_id, runners, instances)
-        or _model_needs_download(runners, download_status)
+        or _model_needs_download(node_id, runners, global_download_status)
         or _init_distributed_backend(runners, all_runners)
         or _load_model(runners, all_runners, global_download_status)
         or _ready_to_warmup(runners, all_runners)
@@ -115,9 +111,15 @@ def _create_runner(
 
 
 def _model_needs_download(
+    node_id: NodeId,
     runners: Mapping[RunnerId, RunnerSupervisor],
-    download_status: Mapping[ModelId, DownloadProgress],
+    global_download_status: Mapping[NodeId, Sequence[DownloadProgress]],
 ) -> DownloadModel | None:
+    local_downloads = global_download_status.get(node_id, [])
+    download_status = {
+        dp.shard_metadata.model_card.model_id: dp for dp in local_downloads
+    }
+
     for runner in runners.values():
         model_id = runner.bound_instance.bound_shard.model_card.model_id
         if isinstance(runner.status, RunnerIdle) and (

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

@@ -11,12 +11,12 @@ from pathlib import Path
 
 import pytest
 
-from exo.shared.models.model_cards import MODEL_CARDS, ModelCard, ModelId
-from exo.worker.download.download_utils import (
+from exo.download.download_utils import (
     download_file_with_retry,
     ensure_models_dir,
     fetch_file_list_with_cache,
 )
+from exo.shared.models.model_cards import MODEL_CARDS, ModelCard, ModelId
 from exo.worker.engines.mlx.utils_mlx import (
     get_eos_token_ids_for_model,
     load_tokenizer_for_model_id,

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

@@ -1,5 +1,5 @@
 import exo.worker.plan as plan_mod
-from exo.shared.types.common import ModelId, NodeId
+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
@@ -45,13 +45,9 @@ def test_plan_requests_download_when_waiting_and_shard_not_downloaded():
     instances = {INSTANCE_1_ID: instance}
     all_runners = {RUNNER_1_ID: RunnerIdle()}
 
-    # No entry for this shard -> should trigger DownloadModel
-    download_status: dict[ModelId, DownloadProgress] = {}
-
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status=download_status,
         global_download_status={NODE_A: []},
         instances=instances,
         all_runners=all_runners,
@@ -92,14 +88,6 @@ def test_plan_loads_model_when_all_shards_downloaded_and_waiting():
         RUNNER_2_ID: RunnerConnected(),
     }
 
-    # Local node has already marked its shard as downloaded (not actually used by _load_model)
-    local_download_status = {
-        MODEL_A_ID: DownloadCompleted(
-            shard_metadata=shard1, node_id=NODE_A, total_bytes=Memory()
-        )
-    }
-
-    # Global view has completed downloads for both nodes
     global_download_status = {
         NODE_A: [
             DownloadCompleted(
@@ -116,7 +104,6 @@ def test_plan_loads_model_when_all_shards_downloaded_and_waiting():
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status=local_download_status,
         global_download_status=global_download_status,
         instances=instances,
         all_runners=all_runners,
@@ -148,23 +135,19 @@ def test_plan_does_not_request_download_when_shard_already_downloaded():
     instances = {INSTANCE_1_ID: instance}
     all_runners = {RUNNER_1_ID: RunnerIdle()}
 
-    # Local status claims the shard is downloaded already
-    local_download_status = {
-        MODEL_A_ID: DownloadCompleted(
-            shard_metadata=shard, node_id=NODE_A, total_bytes=Memory()
-        )
-    }
-
-    # Global view hasn't caught up yet (no completed shards recorded for NODE_A)
+    # Global state shows shard is downloaded for NODE_A
     global_download_status: dict[NodeId, list[DownloadProgress]] = {
-        NODE_A: [],
+        NODE_A: [
+            DownloadCompleted(
+                shard_metadata=shard, node_id=NODE_A, total_bytes=Memory()
+            )
+        ],
         NODE_B: [],
     }
 
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status=local_download_status,
         global_download_status=global_download_status,
         instances=instances,
         all_runners=all_runners,
@@ -202,12 +185,6 @@ def test_plan_does_not_load_model_until_all_shards_downloaded_globally():
         RUNNER_2_ID: RunnerConnected(),
     }
 
-    # Only NODE_A's shard is recorded as downloaded globally
-    local_download_status = {
-        MODEL_A_ID: DownloadCompleted(
-            shard_metadata=shard1, node_id=NODE_A, total_bytes=Memory()
-        )
-    }
     global_download_status = {
         NODE_A: [
             DownloadCompleted(
@@ -220,7 +197,6 @@ def test_plan_does_not_load_model_until_all_shards_downloaded_globally():
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status=local_download_status,
         global_download_status=global_download_status,
         instances=instances,
         all_runners=all_runners,
@@ -245,7 +221,6 @@ def test_plan_does_not_load_model_until_all_shards_downloaded_globally():
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status=local_download_status,
         global_download_status=global_download_status,
         instances=instances,
         all_runners=all_runners,

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

@@ -47,8 +47,7 @@ def test_plan_kills_runner_when_instance_missing():
 
     result = plan_mod.plan(
         node_id=NODE_A,
-        runners=runners,  # type: ignore
-        download_status={},
+        runners=runners,  # type: ignore[arg-type]
         global_download_status={NODE_A: []},
         instances=instances,
         all_runners=all_runners,
@@ -87,8 +86,7 @@ def test_plan_kills_runner_when_sibling_failed():
 
     result = plan_mod.plan(
         node_id=NODE_A,
-        runners=runners,  # type: ignore
-        download_status={},
+        runners=runners,  # type: ignore[arg-type]
         global_download_status={NODE_A: []},
         instances=instances,
         all_runners=all_runners,
@@ -120,7 +118,6 @@ def test_plan_creates_runner_when_missing_for_node():
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,
-        download_status={},
         global_download_status={NODE_A: []},
         instances=instances,
         all_runners=all_runners,
@@ -158,8 +155,7 @@ def test_plan_does_not_create_runner_when_supervisor_already_present():
 
     result = plan_mod.plan(
         node_id=NODE_A,
-        runners=runners,  # type: ignore
-        download_status={},
+        runners=runners,  # type: ignore[arg-type]
         global_download_status={NODE_A: []},
         instances=instances,
         all_runners=all_runners,
@@ -189,7 +185,6 @@ def test_plan_does_not_create_runner_for_unassigned_node():
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status={},
         global_download_status={NODE_A: []},
         instances=instances,
         all_runners=all_runners,

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

@@ -65,7 +65,6 @@ def test_plan_forwards_pending_chat_completion_when_runner_ready():
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status={},
         global_download_status={NODE_A: []},
         instances=instances,
         all_runners=all_runners,
@@ -113,7 +112,6 @@ def test_plan_does_not_forward_chat_completion_if_any_runner_not_ready():
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status={},
         global_download_status={NODE_A: [], NODE_B: []},
         instances=instances,
         all_runners=all_runners,
@@ -158,7 +156,6 @@ def test_plan_does_not_forward_tasks_for_other_instances():
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status={},
         global_download_status={NODE_A: []},
         instances=instances,
         all_runners=all_runners,
@@ -221,7 +218,6 @@ def test_plan_ignores_non_pending_or_non_chat_tasks():
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status={},
         global_download_status={NODE_A: [], NODE_B: []},
         instances=instances,
         all_runners=all_runners,
@@ -261,7 +257,6 @@ def test_plan_returns_none_when_nothing_to_do():
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status={},
         global_download_status={NODE_A: [], NODE_B: []},
         instances=instances,
         all_runners=all_runners,

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

@@ -57,7 +57,6 @@ def test_plan_starts_warmup_for_accepting_rank_when_all_loaded_or_warming():
     result = plan_mod.plan(
         node_id=NODE_B,
         runners=runners,  # type: ignore
-        download_status={},
         global_download_status={NODE_A: []},
         instances=instances,
         all_runners=all_runners,
@@ -99,7 +98,6 @@ def test_plan_starts_warmup_for_rank_zero_after_others_warming():
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status={},
         global_download_status={NODE_A: []},
         instances=instances,
         all_runners=all_runners,
@@ -140,7 +138,6 @@ def test_plan_does_not_start_warmup_for_non_zero_rank_until_all_loaded_or_warmin
     result = plan_mod.plan(
         node_id=NODE_B,
         runners=runners,  # type: ignore
-        download_status={},
         global_download_status={NODE_A: [], NODE_B: []},
         instances=instances,
         all_runners=all_runners,
@@ -185,7 +182,6 @@ def test_plan_does_not_start_warmup_for_rank_zero_until_others_warming():
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status={},
         global_download_status={NODE_A: []},
         instances=instances,
         all_runners=all_runners,
@@ -202,7 +198,6 @@ def test_plan_does_not_start_warmup_for_rank_zero_until_others_warming():
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status={},
         global_download_status={NODE_A: []},
         instances=instances,
         all_runners=all_runners,
@@ -246,7 +241,6 @@ def test_plan_starts_warmup_for_connecting_rank_after_others_warming():
     result = plan_mod.plan(
         node_id=NODE_B,
         runners=runners,  # type: ignore
-        download_status={},
         global_download_status={NODE_B: []},
         instances=instances,
         all_runners=all_runners,
@@ -289,7 +283,6 @@ def test_plan_does_not_start_warmup_for_accepting_rank_until_all_loaded_or_warmi
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status={},
         global_download_status={NODE_A: [], NODE_B: []},
         instances=instances,
         all_runners=all_runners,
@@ -331,7 +324,6 @@ def test_plan_does_not_start_warmup_for_connecting_rank_until_others_warming():
     result = plan_mod.plan(
         node_id=NODE_A,
         runners=runners,  # type: ignore
-        download_status={},
         global_download_status={NODE_A: [], NODE_B: []},
         instances=instances,
         all_runners=all_runners,

tests/headless_runner.py

@@ -11,6 +11,10 @@ from hypercorn.asyncio import serve  # pyright: ignore[reportUnknownVariableType
 from loguru import logger
 from pydantic import BaseModel
 
+from exo.download.impl_shard_downloader import (
+    build_full_shard,
+    exo_shard_downloader,
+)
 from exo.shared.logging import InterceptLogger, logger_setup
 from exo.shared.models.model_cards import MODEL_CARDS, ModelId
 from exo.shared.types.api import ChatCompletionMessage, ChatCompletionTaskParams
@@ -36,10 +40,6 @@ from exo.shared.types.worker.runners import RunnerId, ShardAssignments
 from exo.shared.types.worker.shards import PipelineShardMetadata, TensorShardMetadata
 from exo.utils.channels import MpReceiver, MpSender, channel, mp_channel
 from exo.utils.info_gatherer.info_gatherer import GatheredInfo, InfoGatherer
-from exo.worker.download.impl_shard_downloader import (
-    build_full_shard,
-    exo_shard_downloader,
-)
 from exo.worker.runner.bootstrap import entrypoint
 
 

uv.lock

@@ -412,7 +412,7 @@ requires-dist = [
     { name = "huggingface-hub", specifier = ">=0.33.4" },
     { name = "hypercorn", specifier = ">=0.18.0" },
     { name = "loguru", specifier = ">=0.7.3" },
-    { name = "mflux", specifier = ">=0.14.2" },
+    { name = "mflux", specifier = "==0.15.4" },
     { name = "mlx", marker = "sys_platform == 'darwin'", specifier = "==0.30.3" },
     { name = "mlx", extras = ["cpu"], marker = "sys_platform == 'linux'", specifier = "==0.30.3" },
     { name = "mlx-lm", git = "https://github.com/AlexCheema/mlx-lm.git?rev=fix-transformers-5.0.0rc2" },
@@ -458,16 +458,6 @@ 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"
@@ -997,7 +987,7 @@ wheels = [
 
 [[package]]
 name = "mflux"
-version = "0.15.3"
+version = "0.15.4"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "filelock", marker = "sys_platform == 'darwin' or sys_platform == 'linux'" },
@@ -1023,9 +1013,9 @@ dependencies = [
     { name = "twine", marker = "sys_platform == 'darwin' or sys_platform == 'linux'" },
     { name = "urllib3", marker = "sys_platform == 'darwin' or sys_platform == 'linux'" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/23/c5/dd12e16714702255d89b7ccc6f217c405a9fdcf2af950a2236892c50a219/mflux-0.15.3.tar.gz", hash = "sha256:e32ea66a81aad4f77eea2415b17c27fc3d9ce662a842565c62871ff570f4ef2f", size = 740701, upload-time = "2026-01-19T22:54:59.066Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/a6/f8/95322db7a865e4df6bad108b1c99aa7fbe211aac3f298f3ad696c2744a39/mflux-0.15.4.tar.gz", hash = "sha256:138e1aedae86e13eafeb8faec017945fcdcca42c3234daabcd81a83c9a202ace", size = 741228, upload-time = "2026-01-20T15:39:26.807Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/cf/9f/a673ee12877a0943a4059c51b5beb6cf909c92f25384365cf8beeb475159/mflux-0.15.3-py3-none-any.whl", hash = "sha256:631cfcc038f27e9bd0ff76c25c2bc7373562b8f64cf0ce961fc268a246fa699e", size = 987270, upload-time = "2026-01-19T22:54:57.155Z" },
+    { url = "https://files.pythonhosted.org/packages/8e/be/81cf4ce2d1933b9b210c028a05ac95e958008c0d43e377a5f2757b7f2d4d/mflux-0.15.4-py3-none-any.whl", hash = "sha256:f04d9b1d7c5cd67880f483ab29fb2097648a25459eef9c5ee6480fad46de5e82", size = 987644, upload-time = "2026-01-20T15:39:24.817Z" },
 ]
 
 [[package]]
@@ -2227,6 +2217,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/44/6f/7120676b6d73228c96e17f1f794d8ab046fc910d781c8d151120c3f1569e/toml-0.10.2-py2.py3-none-any.whl", hash = "sha256:806143ae5bfb6a3c6e736a764057db0e6a0e05e338b5630894a5f779cabb4f9b", size = 16588, upload-time = "2020-11-01T01:40:20.672Z" },
 ]
 
+[[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, upload-time = "2026-01-13T01:14:53.304Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/b5/11/87d6d29fb5d237229d67973a6c9e06e048f01cf4994dee194ab0ea841814/tomlkit-0.14.0-py3-none-any.whl", hash = "sha256:592064ed85b40fa213469f81ac584f67a4f2992509a7c3ea2d632208623a3680", size = 39310, upload-time = "2026-01-13T01:14:51.965Z" },
+]
+
 [[package]]
 name = "torch"
 version = "2.9.1"