diff --git a/tools/ui/src/app.css b/tools/ui/src/app.css
index f9b544bebc..e79e577bc4 100644
--- a/tools/ui/src/app.css
+++ b/tools/ui/src/app.css
@@ -26,6 +26,7 @@
 	--border: oklch(0.875 0 0);
 	--input: oklch(0.92 0 0);
 	--ring: oklch(0.708 0 0);
+	--brand: #f65e00;
 	--chart-1: oklch(0.646 0.222 41.116);
 	--chart-2: oklch(0.6 0.118 184.704);
 	--chart-3: oklch(0.398 0.07 227.392);
@@ -115,6 +116,7 @@
 	--color-muted-foreground: var(--muted-foreground);
 	--color-accent: var(--accent);
 	--color-accent-foreground: var(--accent-foreground);
+	--color-brand: var(--brand);
 	--color-destructive: var(--destructive);
 	--color-border: var(--border);
 	--color-input: var(--input);
diff --git a/tools/ui/src/lib/components/app/models/ModelId.svelte b/tools/ui/src/lib/components/app/models/ModelId.svelte
index 24559114ca..49c6f5051e 100644
--- a/tools/ui/src/lib/components/app/models/ModelId.svelte
+++ b/tools/ui/src/lib/components/app/models/ModelId.svelte
@@ -31,6 +31,8 @@
 		contextLength?: number;
 		/** Min/max GGUF file size (main + draft) across quants; renders a range when set. */
 		sizeRange?: { min: number; max: number } | null;
+		/** Params badge fallback (formatted) when the model id carries no params token. */
+		params?: string;
 		draftVariants?: DraftVariant[];
 		/** Allow badges to wrap onto new lines instead of truncating. */
 		wrap?: boolean;
@@ -52,6 +54,7 @@
 		iconsOnNewLine = false,
 		modalities,
 		modelId,
+		params,
 		showRaw = undefined,
 		showRawTooltip = false,
 		sizeRange,
@@ -104,9 +107,9 @@
 				</span>
 			{/if}
 
-			{#if parsed.params && !hideParameters}
+			{#if (parsed.params || params) && !hideParameters}
 				<span class={badgeClass}>
-					{parsed.params}{parsed.activatedParams ? `-${parsed.activatedParams}` : ''}
+					{parsed.params ?? params}{parsed.activatedParams ? `-${parsed.activatedParams}` : ''}
 				</span>
 			{/if}
 
diff --git a/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverChatTemplateDialog.svelte b/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverChatTemplateDialog.svelte
new file mode 100644
index 0000000000..f4d9deafb1
--- /dev/null
+++ b/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverChatTemplateDialog.svelte
@@ -0,0 +1,39 @@
+<script lang="ts">
+	import { Copy } from '@lucide/svelte';
+	import * as Dialog from '$lib/components/ui/dialog';
+	import { copyToClipboard } from '$lib/utils';
+
+	interface Props {
+		open?: boolean;
+		chatTemplate: string;
+		onOpenChange?: (open: boolean) => void;
+	}
+
+	let { chatTemplate, onOpenChange, open = $bindable(false) }: Props = $props();
+
+	function handleOpenChange(value: boolean) {
+		open = value;
+		onOpenChange?.(value);
+	}
+</script>
+
+<Dialog.Root {open} onOpenChange={handleOpenChange}>
+	<Dialog.Content
+		class="flex max-h-[calc(100vh-4rem)] flex-col gap-0 p-0 md:w-[calc(100vw-4rem)]! md:max-w-4xl!"
+	>
+		<Dialog.Header class="flex-row items-center justify-between border-b border-border/40 p-4">
+			<Dialog.Title class="text-sm font-semibold">Chat template</Dialog.Title>
+			<button
+				type="button"
+				onclick={() => copyToClipboard(chatTemplate)}
+				class="inline-flex items-center gap-1.5 rounded-md border px-2 py-1 text-xs font-medium transition-colors hover:bg-muted"
+			>
+				<Copy class="h-3.5 w-3.5" />
+				Copy
+			</button>
+		</Dialog.Header>
+
+		<pre
+			class="flex-1 overflow-auto p-4 font-mono text-xs break-all whitespace-pre-wrap text-muted-foreground">{chatTemplate}</pre>
+	</Dialog.Content>
+</Dialog.Root>
diff --git a/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverDetails.svelte b/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverDetails.svelte
index 4d57b2c526..e5f50aa595 100644
--- a/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverDetails.svelte
+++ b/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverDetails.svelte
@@ -95,7 +95,10 @@
 			}
 
 			details = info;
-			files = HuggingFaceService.filterByExtension(tree, '.gguf');
+			files = HuggingFaceService.filterByExtension(
+				HuggingFaceService.collapseGgufShards(tree),
+				'.gguf'
+			);
 			readme = readmeText;
 		} catch (err) {
 			error = err instanceof Error ? err.message : 'Failed to load model';
@@ -131,7 +134,12 @@
 			{hasReasoning}
 		/>
 
-		<ModelsDiscoverDetailsDownloadOptions {modelId} {bitDepthRows} />
+		<ModelsDiscoverDetailsDownloadOptions
+			{modelId}
+			{files}
+			{bitDepthRows}
+			nativeCtxTokens={gguf?.context_length ?? 0}
+		/>
 
 		<TerminalCommands {modelId} {draftVariants} />
 
diff --git a/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverDetailsDownloadOptions.svelte b/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverDetailsDownloadOptions.svelte
index 31f6e36b78..160e66372c 100644
--- a/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverDetailsDownloadOptions.svelte
+++ b/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverDetailsDownloadOptions.svelte
@@ -1,15 +1,20 @@
 <script lang="ts">
 	import DialogModelDownload from './DialogModelDownload.svelte';
 	import DownloadProgressBar from './DownloadProgressBar.svelte';
-	import { Check, MessageSquareCode } from '@lucide/svelte';
+	import { Check, Cpu, MessageSquareCode, TriangleAlert, X } from '@lucide/svelte';
+	import { browser } from '$app/environment';
+	import * as Tooltip from '$lib/components/ui/tooltip';
 	import type { GgufVariantTagInput } from '$lib/services';
 	import { HuggingFaceService, ModelsService } from '$lib/services';
-	import { modelsStore } from '$lib/stores';
+	import { modelsStore, settingsStore } from '$lib/stores';
 	import type { HfModelSibling } from '$lib/types/huggingface';
+	import { computeFileCompatibilityTiers, detectOs, resolveDeviceMemoryGb } from '$lib/utils';
 
 	interface Props {
 		modelId: string;
+		files: HfModelSibling[];
 		bitDepthRows: BitDepthRow[];
+		nativeCtxTokens: number;
 	}
 
 	interface PendingDownload {
@@ -21,19 +26,64 @@
 
 	type BitDepthRow = { bitDepth: number; files: HfModelSibling[] };
 
-	let { bitDepthRows, modelId }: Props = $props();
+	let { bitDepthRows, files, modelId, nativeCtxTokens }: Props = $props();
 
 	let pendingDownload = $state<PendingDownload | null>(null);
+
+	let deviceMemoryGb = $derived(
+		resolveDeviceMemoryGb(Number(settingsStore.config.deviceMemoryGb) || 0)
+	);
+	let osLabel = $derived(browser ? detectOs(navigator.userAgent) : 'unknown');
+	let tiers = $derived(computeFileCompatibilityTiers(files, nativeCtxTokens, deviceMemoryGb));
+
+	function buttonClass(parts: {
+		isDownloaded: boolean;
+		isFailed: boolean;
+		isUnavailable: boolean;
+	}): string {
+		const { isDownloaded, isFailed, isUnavailable } = parts;
+		const classes = [
+			'relative inline-flex items-center gap-1 overflow-hidden rounded-md border bg-muted px-2 py-1 text-left font-mono text-xs transition-colors'
+		];
+
+		// Buttons stay neutral; only the leading compatibility badge carries
+		// color (green/yellow/red). Unavailable quants are greyed + disabled.
+		if (isUnavailable) {
+			classes.push('cursor-not-allowed opacity-50');
+		} else {
+			classes.push('cursor-pointer hover:border-primary/60 hover:bg-primary/5');
+		}
+
+		if (isDownloaded && !isFailed) {
+			classes.push('border-foreground bg-muted');
+		} else if (isFailed) {
+			classes.push('border-destructive');
+		}
+
+		return classes.join(' ');
+	}
 </script>
 
 {#if bitDepthRows.length}
 	<section class="space-y-3">
-		<h2
-			class="flex items-center gap-1.5 text-xs font-semibold tracking-wide text-muted-foreground uppercase"
-		>
-			<MessageSquareCode class="h-3.5 w-3.5" />
-			Download options
-		</h2>
+		<div class="flex flex-wrap items-center justify-between gap-2">
+			<h2
+				class="flex items-center gap-1.5 text-xs font-semibold tracking-wide text-muted-foreground uppercase"
+			>
+				<MessageSquareCode class="h-3.5 w-3.5" />
+				Download options
+			</h2>
+
+			<span
+				class="inline-flex items-center gap-1.5 rounded-full border bg-background px-2.5 py-1 text-xs font-medium"
+			>
+				<Cpu class="h-3 w-3 text-muted-foreground" />
+				{osLabel}
+				{#if deviceMemoryGb > 0}
+					<span class="text-muted-foreground">({deviceMemoryGb} GB)</span>
+				{/if}
+			</span>
+		</div>
 		<div class="space-y-2">
 			{#each bitDepthRows as row (row.bitDepth)}
 				<div class="grid grid-cols-[5rem_1fr] items-start gap-3">
@@ -59,60 +109,97 @@
 								? modelsStore.status.isDraftDownloaded(modelId, file.path)
 								: modelsStore.status.isModelDownloaded(hfRepoWithTag)}
 							{@const isFailed = modelsStore.status.hasFailedDownload(hfRepoWithTag)}
-							<button
-								type="button"
-								onclick={() =>
-									(pendingDownload = {
-										filePath: file.path,
-										quant: meta?.quant ?? null,
-										sizeBytes: file.size ?? null,
-										variant: meta?.variant ?? null
-									})}
-								title={isDownloading
-									? `Downloading ${file.path}`
-									: isDownloaded
-										? `Already downloaded: ${file.path}`
-										: isFailed
-											? `Last attempt failed: ${file.path}. Click to retry.`
+							{@const tier = tiers.get(file.path)}
+							{@const isUnavailable =
+								tier === 'none' && !isDownloaded && !isDownloading && !isFailed}
+							{@const isAvailable = tier === 'full' && !isDownloaded && !isDownloading && !isFailed}
+							{@const isLimited =
+								tier === 'limited' && !isDownloaded && !isDownloading && !isFailed}
+							{@const tooltipText = isDownloading
+								? `Downloading ${file.path}`
+								: isDownloaded
+									? `Already downloaded: ${file.path}`
+									: isFailed
+										? `Last attempt failed: ${file.path}. Click to retry.`
+										: isUnavailable
+											? `Does not fit this device: ${file.path}`
 											: `Download ${file.path}`}
-								class="relative inline-flex cursor-pointer items-center gap-1 overflow-hidden rounded-md border bg-background px-2 py-1 text-left font-mono text-xs transition-colors hover:border-primary/60 hover:bg-primary/5"
-								class:border-foreground={isDownloaded && !isDownloading && !isFailed}
-								class:bg-muted={isDownloaded && !isDownloading && !isFailed}
-								class:border-destructive={isFailed && !isDownloading}
-							>
-								{#if isDownloaded && !isDownloading}
-									<Check class="h-3 w-3 text-foreground/70" />
-								{/if}
-								{#if isFailed && !isDownloading && !isDownloaded}
-									<span
-										class="rounded bg-destructive px-1 py-0.5 text-[10px] font-semibold tracking-wide text-destructive-foreground uppercase"
-									>
-										Failed
-									</span>
-								{/if}
-								{#if meta?.variant}
-									<span
-										class="rounded bg-primary px-1 py-0.5 text-[10px] font-semibold tracking-wide text-primary-foreground uppercase"
-									>
-										{meta.variant}
-									</span>
-								{/if}
-								<span class="font-medium">{label}</span>
-								<span class="text-muted-foreground">
-									{#if isDownloading && progress && progress.totalBytes > 0}
-										{Math.round((progress.downloadedBytes / progress.totalBytes) * 100)}%
-									{:else}
-										{HuggingFaceService.formatFileSize(file.size ?? 0)}
+							<Tooltip.Root>
+								<Tooltip.Trigger
+									type="button"
+									onclick={() => {
+										if (isUnavailable) return;
+
+										pendingDownload = {
+											filePath: file.path,
+											quant: meta?.quant ?? null,
+											sizeBytes: file.size ?? null,
+											variant: meta?.variant ?? null
+										};
+									}}
+									aria-disabled={isUnavailable}
+									class={buttonClass({
+										isDownloaded,
+										isFailed,
+										isUnavailable
+									})}
+								>
+									{#if isAvailable}
+										<span
+											class="flex h-3.5 w-3.5 shrink-0 items-center justify-center rounded-full bg-green-600"
+										>
+											<Check class="h-2.5 w-2.5 text-white" />
+										</span>
+									{:else if isLimited}
+										<span
+											class="flex h-3.5 w-3.5 shrink-0 items-center justify-center rounded-full bg-yellow-500"
+										>
+											<TriangleAlert class="h-2.5 w-2.5 text-white" />
+										</span>
+									{:else if isUnavailable}
+										<span
+											class="flex h-3.5 w-3.5 shrink-0 items-center justify-center rounded-full bg-red-600"
+										>
+											<X class="h-2.5 w-2.5 text-white" />
+										</span>
 									{/if}
-								</span>
-								{#if isDownloading && progress}
-									<DownloadProgressBar
-										overlay
-										downloadedBytes={progress.downloadedBytes}
-										totalBytes={progress.totalBytes}
-									/>
-								{/if}
-							</button>
+									{#if isFailed && !isDownloading && !isDownloaded}
+										<span
+											class="rounded bg-destructive px-1 py-0.5 text-[10px] font-semibold tracking-wide text-destructive-foreground uppercase"
+										>
+											Failed
+										</span>
+									{/if}
+									{#if meta?.variant}
+										<span
+											class="rounded bg-primary px-1 py-0.5 text-[10px] font-semibold tracking-wide text-primary-foreground uppercase"
+										>
+											{meta.variant}
+										</span>
+									{/if}
+									<span class="font-medium {isDownloaded ? '' : 'text-muted-foreground/80'}"
+										>{label}</span
+									>
+									<span class={isDownloaded ? '' : 'text-muted-foreground/80'}>
+										{#if isDownloading && progress && progress.totalBytes > 0}
+											{Math.round((progress.downloadedBytes / progress.totalBytes) * 100)}%
+										{:else}
+											{HuggingFaceService.formatFileSize(file.size ?? 0)}
+										{/if}
+									</span>
+									{#if isDownloading && progress}
+										<DownloadProgressBar
+											overlay
+											downloadedBytes={progress.downloadedBytes}
+											totalBytes={progress.totalBytes}
+										/>
+									{/if}
+								</Tooltip.Trigger>
+
+								<Tooltip.Content>
+									<p>{tooltipText}</p>
+								</Tooltip.Content>
+							</Tooltip.Root>
 						{/each}
 					</div>
 				</div>
diff --git a/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverDetailsHeader.svelte b/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverDetailsHeader.svelte
index ac1546dd0b..d62ef4e77b 100644
--- a/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverDetailsHeader.svelte
+++ b/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverDetailsHeader.svelte
@@ -1,10 +1,21 @@
 <script lang="ts">
 	import ModelsDiscoverAvatar from './ModelsDiscoverAvatar.svelte';
+	import ModelsDiscoverChatTemplateDialog from './ModelsDiscoverChatTemplateDialog.svelte';
 	import ModelsDiscoverDetailsName from './ModelsDiscoverDetailsName.svelte';
-	import { Download, ExternalLink, Heart, Image, Lightbulb, Wrench } from '@lucide/svelte';
+	import {
+		Download,
+		ExternalLink,
+		Heart,
+		Image,
+		Lightbulb,
+		MessageSquareCode,
+		Wrench
+	} from '@lucide/svelte';
+	import * as Tooltip from '$lib/components/ui/tooltip';
 	import { HuggingFaceService } from '$lib/services';
 	import { modelsHubStore } from '$lib/stores';
 	import type { HfModelDetailInfo, HfModelGguf } from '$lib/types/huggingface';
+	import { formatParameters } from '$lib/utils';
 
 	interface Props {
 		modelId: string;
@@ -31,6 +42,8 @@
 	let description = $derived(
 		modelsHubStore.descriptionFor(modelId) ?? details.cardData?.description
 	);
+
+	let chatTemplateOpen = $state(false);
 </script>
 
 <header class="space-y-3">
@@ -76,7 +89,7 @@
 	<div class="flex flex-wrap items-center gap-1.5">
 		{#if gguf?.total}
 			<span class="rounded bg-secondary px-2 py-0.5 text-xs font-medium text-secondary-foreground">
-				{HuggingFaceService.formatFileSize(gguf.total).replace(' B', '')}B params
+				{formatParameters(gguf.total)} params
 			</span>
 		{/if}
 		{#if gguf?.architecture}
@@ -91,6 +104,16 @@
 				{gguf.context_length.toLocaleString()} ctx
 			</span>
 		{/if}
+		{#if gguf?.chat_template}
+			<button
+				type="button"
+				onclick={() => (chatTemplateOpen = true)}
+				class="inline-flex items-center gap-1 rounded bg-secondary px-2 py-0.5 text-xs font-medium text-secondary-foreground transition-colors hover:bg-secondary/70"
+			>
+				<MessageSquareCode class="h-3 w-3" />
+				Chat template
+			</button>
+		{/if}
 		{#if licenseTag}
 			<span class="rounded bg-muted px-2 py-0.5 text-xs font-medium text-muted-foreground">
 				{licenseTag}
@@ -105,33 +128,46 @@
 		{/if}
 	</div>
 
-	<!-- Capability badges -->
+	<!-- Capability / modality icons, matching the list item's icon style -->
 	{#if hasVision || hasTools || hasReasoning}
-		<div class="flex flex-wrap items-center gap-1.5">
+		<div class="flex flex-wrap items-center gap-2.5 text-muted-foreground">
 			{#if hasVision}
-				<span
-					class="inline-flex items-center gap-1 rounded bg-primary/10 px-2 py-0.5 text-xs font-medium text-primary"
-				>
-					<Image class="h-3 w-3" />
-					Vision
-				</span>
+				<Tooltip.Root>
+					<Tooltip.Trigger>
+						<Image class="h-4 w-4" />
+					</Tooltip.Trigger>
+					<Tooltip.Content>
+						<p>Vision</p>
+					</Tooltip.Content>
+				</Tooltip.Root>
 			{/if}
 			{#if hasTools}
-				<span
-					class="inline-flex items-center gap-1 rounded bg-primary/10 px-2 py-0.5 text-xs font-medium text-primary"
-				>
-					<Wrench class="h-3 w-3" />
-					Tool use
-				</span>
+				<Tooltip.Root>
+					<Tooltip.Trigger>
+						<Wrench class="h-4 w-4" />
+					</Tooltip.Trigger>
+					<Tooltip.Content>
+						<p>Tool use</p>
+					</Tooltip.Content>
+				</Tooltip.Root>
 			{/if}
 			{#if hasReasoning}
-				<span
-					class="inline-flex items-center gap-1 rounded bg-primary/10 px-2 py-0.5 text-xs font-medium text-primary"
-				>
-					<Lightbulb class="h-3 w-3" />
-					Reasoning
-				</span>
+				<Tooltip.Root>
+					<Tooltip.Trigger>
+						<Lightbulb class="h-4 w-4" />
+					</Tooltip.Trigger>
+					<Tooltip.Content>
+						<p>Reasoning</p>
+					</Tooltip.Content>
+				</Tooltip.Root>
 			{/if}
 		</div>
 	{/if}
 </header>
+
+{#if gguf?.chat_template}
+	<ModelsDiscoverChatTemplateDialog
+		bind:open={chatTemplateOpen}
+		chatTemplate={gguf.chat_template}
+	/>
+{/if}
diff --git a/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverInfo.svelte b/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverInfo.svelte
index afe21aec74..9d4e24df03 100644
--- a/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverInfo.svelte
+++ b/tools/ui/src/lib/components/app/models/discover/ModelsDiscoverInfo.svelte
@@ -1,11 +1,11 @@
 <script lang="ts">
 	import ModelId from '../ModelId.svelte';
 	import { type DraftVariant } from '$lib/constants';
-	import { HuggingFaceService } from '$lib/services';
+	import { HuggingFaceService, ModelsService } from '$lib/services';
 	import { modelsHubStore } from '$lib/stores';
 	import type { HfModelInfo } from '$lib/types/huggingface';
 	import type { ModelModalities } from '$lib/types/models';
-	import { detectToolUseSupport } from '$lib/utils';
+	import { detectToolUseSupport, formatParameters } from '$lib/utils';
 	import { SvelteSet } from 'svelte/reactivity';
 
 	interface Props {
@@ -16,6 +16,35 @@
 
 	let contextLength = $derived(model.gguf?.context_length);
 
+	// Params badge fallback: the id usually carries the count (`Qwen3.8-27B`),
+	// but ids like `Kimi-K3` do not. Fall back to the HF param count
+	// (`gguf.total`); search results omit `gguf`, so fetch details lazily only
+	// when the name has no params token.
+	let fetchedParams = $state<number | null>(null);
+
+	$effect(() => {
+		fetchedParams = null;
+
+		if (model.gguf?.total || ModelsService.parseModelId(model.id).params) return;
+
+		let cancelled = false;
+
+		void HuggingFaceService.getDetails(model.id).then((info) => {
+			if (!cancelled && info?.gguf?.total) fetchedParams = info.gguf.total;
+		});
+
+		return () => {
+			cancelled = true;
+		};
+	});
+
+	let hfParams = $derived(model.gguf?.total ?? fetchedParams);
+	let paramsFallback = $derived(
+		hfParams && !ModelsService.parseModelId(model.id).params
+			? formatParameters(hfParams, 0)
+			: undefined
+	);
+
 	// Reasoning support from the chat template, matching the details view.
 	let supportsThinking = $derived(
 		Boolean(model.gguf?.chat_template && /think|reasoning/i.test(model.gguf.chat_template))
@@ -113,6 +142,7 @@
 		{contextLength}
 		{sizeRange}
 		{draftVariants}
+		params={paramsFallback}
 		iconsOnNewLine
 		wrap
 		class="min-w-0"
diff --git a/tools/ui/src/lib/components/app/models/discover/index.ts b/tools/ui/src/lib/components/app/models/discover/index.ts
index 181db3a729..b52ca871dd 100644
--- a/tools/ui/src/lib/components/app/models/discover/index.ts
+++ b/tools/ui/src/lib/components/app/models/discover/index.ts
@@ -70,6 +70,13 @@ export { default as ModelsDiscoverDetailsName } from './ModelsDiscoverDetailsNam
  */
 export { default as ModelsDiscoverDetailsDownloadOptions } from './ModelsDiscoverDetailsDownloadOptions.svelte';
 
+/**
+ * **ModelsDiscoverChatTemplateDialog** - Chat template viewer
+ *
+ * Shows the model's chat template in a scrollable dialog with a copy button.
+ */
+export { default as ModelsDiscoverChatTemplateDialog } from './ModelsDiscoverChatTemplateDialog.svelte';
+
 /**
  * **ModelsDiscoverDetailsReadme** - Detail view README
  *
diff --git a/tools/ui/src/lib/constants/model-id.constants.ts b/tools/ui/src/lib/constants/model-id.constants.ts
index ea0ed7f8fb..b1d7cf7b17 100644
--- a/tools/ui/src/lib/constants/model-id.constants.ts
+++ b/tools/ui/src/lib/constants/model-id.constants.ts
@@ -43,10 +43,11 @@ export const MODEL_ID = {
 	PARAMS_RE: /^[Ee]?\d+(\.\d+)?[BbMmKkTt]$/,
 
 	/**
-	 * Matches a quantization/precision segment, e.g. `Q4_K_M`, `IQ4_XS`, `F16`, `BF16`, `MXFP4`.
-	 * Case-insensitive to handle both uppercase and lowercase inputs.
+	 * Matches a quantization/precision segment, e.g. `Q4_K_M`, `IQ4_XS`, `TQ1_0`,
+	 * `F16`, `BF16`, `MXFP4`. Case-insensitive to handle both cases.
 	 */
-	QUANTIZATION_SEGMENT_RE: /^(I?Q\d+(_[A-Z0-9]+)*|F\d+|BF\d+|MXFP\d+(_[A-Z0-9]+)*)$/i,
+	QUANTIZATION_SEGMENT_RE:
+		/^(I?Q\d+(_[A-Z0-9]+)*|TQ\d+(_[A-Z0-9]+)*|F\d+|BF\d+|MXFP\d+(_[A-Z0-9]+)*)$/i,
 
 	/** Separates the model path from the quantization tag, e.g. `model:Q4_K_M`. */
 	QUANTIZATION_SEPARATOR: ':',
diff --git a/tools/ui/src/lib/constants/settings-keys.constants.ts b/tools/ui/src/lib/constants/settings-keys.constants.ts
index 2c923cee38..dbdb395425 100644
--- a/tools/ui/src/lib/constants/settings-keys.constants.ts
+++ b/tools/ui/src/lib/constants/settings-keys.constants.ts
@@ -16,6 +16,7 @@ export const SETTINGS_KEYS = {
 	CUSTOM_CSS: 'customCss',
 	// PY_INTERPRETER_ENABLED: 'pyInterpreterEnabled',
 	CUSTOM_JSON: 'customJson',
+	DEVICE_MEMORY_GB: 'deviceMemoryGb',
 	DISABLE_AUTO_SCROLL: 'disableAutoScroll',
 	// Developer
 	DISABLE_REASONING_PARSING: 'disableReasoningParsing',
diff --git a/tools/ui/src/lib/constants/settings.constants.ts b/tools/ui/src/lib/constants/settings.constants.ts
index 7140bbcc4a..61cf339bf3 100644
--- a/tools/ui/src/lib/constants/settings.constants.ts
+++ b/tools/ui/src/lib/constants/settings.constants.ts
@@ -117,6 +117,14 @@ export const SETTINGS_REGISTRY: SettingsSectionEntry[] = [
 				label: 'Show microphone on empty input',
 				type: SettingsFieldType.CHECKBOX
 			},
+			{
+				defaultValue: 0,
+				help: 'Total device memory (RAM) in GB, used to estimate which models can run. Set to 0 to auto-detect from the browser when possible.',
+				isPositiveInteger: true,
+				key: SETTINGS_KEYS.DEVICE_MEMORY_GB,
+				label: 'Device memory (GB)',
+				type: SettingsFieldType.INPUT
+			},
 			{
 				defaultValue: false,
 				help: 'Enable "Continue" button for assistant messages, including reasoning models.',
diff --git a/tools/ui/src/lib/services/huggingface.service.ts b/tools/ui/src/lib/services/huggingface.service.ts
index bd149c857d..21f112bc63 100644
--- a/tools/ui/src/lib/services/huggingface.service.ts
+++ b/tools/ui/src/lib/services/huggingface.service.ts
@@ -198,6 +198,47 @@ export class HuggingFaceService {
 		Q8_0: 8
 	};
 
+	/**
+	 * Collapse split GGUF shard sets (`-00001-of-00015.gguf`, ...) to their first
+	 * shard, summing every shard's size so the kept entry reflects the whole
+	 * quant. Non-sharded files pass through unchanged. Downloads are tag-based
+	 * (`repo:quant`), so the first shard is enough to represent the set.
+	 */
+	static collapseGgufShards(siblings: HfModelSibling[]): HfModelSibling[] {
+		const sizeByPath = new Map(siblings.map((f) => [f.path, f.size ?? 0]));
+		const result: HfModelSibling[] = [];
+
+		for (const file of siblings) {
+			const match = /-(\d{5})-of-(\d{5})\.gguf$/i.exec(file.path);
+
+			if (!match) {
+				result.push(file);
+
+				continue;
+			}
+
+			// Keep only the first shard; its size becomes the whole shard set's.
+			if (match[1] !== '00001') continue;
+
+			const total = parseInt(match[2], 10);
+			const stem = file.path.slice(0, file.path.length - match[0].length);
+
+			let size = 0;
+
+			for (let i = 1; i <= total; i++) {
+				const shard = `${stem}-${String(i).padStart(5, '0')}-of-${String(total).padStart(5, '0')}.gguf`;
+
+				size += sizeByPath.get(shard) ?? 0;
+			}
+
+			result.push({ ...file, size });
+		}
+
+		return result;
+	}
+
+	// GGUF Model Browsing
+
 	/**
 	 * Extract the GGUF quantization token (e.g. `Q4_K_M`) and any draft/aux variant
 	 * (`mtp`, `dflash`, `mmproj`) from a `.gguf` filename. The variant shows up
@@ -249,14 +290,18 @@ export class HuggingFaceService {
 		// - For embedded MTP like `Hy3-IQ1_M-mtp.gguf` we have `Hy3-IQ1_M` and `IQ1_M` matches.
 		// - For main files like `Llama-3-8B-Q4_K_M.gguf` we land on the trailing quant.
 		const segments = source.split(MODEL_ID.SEGMENT_SEPARATOR);
-		const quantSeg = segments.find((seg) => MODEL_ID.QUANTIZATION_SEGMENT_RE.test(seg));
-		const quant = quantSeg ? quantSeg.toUpperCase() : null;
+		const quantIdx = segments.findIndex((seg) => MODEL_ID.QUANTIZATION_SEGMENT_RE.test(seg));
+
+		let quant = quantIdx >= 0 ? segments[quantIdx].toUpperCase() : null;
+
+		// Recombine a `UD-` (Unsloth Dynamic) prefix, e.g. `...-UD-Q4_K_XL.gguf`.
+		if (quant && quantIdx > 0 && segments[quantIdx - 1].toUpperCase() === 'UD') {
+			quant = `UD-${quant}`;
+		}
 
 		return { quant, variant, variantForm };
 	}
 
-	// GGUF Model Browsing
-
 	/**
 	 * Filter raw siblings by file extension and sort by size descending.
 	 */
@@ -300,19 +345,6 @@ export class HuggingFaceService {
 		return `${bytes} B`;
 	}
 
-	/**
-	 * Format a min-max size range with a single shared unit and no spaces
-	 * around the dash, e.g. `19.0-28.6 GB`.
-	 */
-	static formatSizeRange(min: number, max: number): string {
-		const unit = max >= 1_000_000_000 ? 'GB' : max >= 1_000_000 ? 'MB' : max >= 1_000 ? 'KB' : 'B';
-		const div =
-			unit === 'GB' ? 1_000_000_000 : unit === 'MB' ? 1_000_000 : unit === 'KB' ? 1_000 : 1;
-		const fmt = (n: number) => (div === 1 ? `${n}` : `${(n / div).toFixed(1)}`);
-
-		return `${fmt(min)}-${fmt(max)} ${unit}`;
-	}
-
 	/**
 	 * Format likes count with K suffix if applicable
 	 */
@@ -346,6 +378,19 @@ export class HuggingFaceService {
 		return `${Math.floor(diffDays / 365)} years ago`;
 	}
 
+	/**
+	 * Format a min-max size range with a single shared unit and no spaces
+	 * around the dash, e.g. `19.0-28.6 GB`.
+	 */
+	static formatSizeRange(min: number, max: number): string {
+		const unit = max >= 1_000_000_000 ? 'GB' : max >= 1_000_000 ? 'MB' : max >= 1_000 ? 'KB' : 'B';
+		const div =
+			unit === 'GB' ? 1_000_000_000 : unit === 'MB' ? 1_000_000 : unit === 'KB' ? 1_000 : 1;
+		const fmt = (n: number) => (div === 1 ? `${n}` : `${(n / div).toFixed(1)}`);
+
+		return `${fmt(min)}-${fmt(max)} ${unit}`;
+	}
+
 	// Model Details & Files
 
 	/**
@@ -411,7 +456,17 @@ export class HuggingFaceService {
 	 * Returns `null` for unrecognized tokens.
 	 */
 	static getBitDepth(quant: string): number | null {
-		return HuggingFaceService.QUANT_BIT_DEPTH[quant] ?? null;
+		// Strip a leading `UD-` (Unsloth Dynamic) prefix before lookup.
+		const base = quant.replace(/^UD-/i, '');
+		const direct = HuggingFaceService.QUANT_BIT_DEPTH[base];
+
+		if (direct !== undefined) return direct;
+
+		// Fall back to the leading precision digits for variants missing from the
+		// map, e.g. `Q4_K_XL` -> 4, `IQ2_XXS` -> 2, `TQ1_0` -> 1, `BF16` -> 16.
+		const match = /^(?:I?Q|TQ|BF|F|MXFP)?(\d+)/i.exec(base);
+
+		return match ? parseInt(match[1], 10) : null;
 	}
 
 	/**
@@ -529,23 +584,35 @@ export class HuggingFaceService {
 	}
 
 	/**
-	 * Get repository file tree to list available GGUF variants
+	 * Get repository file tree to list available GGUF variants. Recursive so
+	 * repos that keep quants in per-quant subdirectories (e.g. `UD-Q4_K_XL/`)
+	 * are included; follows cursor pagination for repos over one page.
 	 */
 	static async getTree(modelId: string): Promise<HfModelSibling[]> {
-		const url = `https://huggingface.co/api/models/${modelId}/tree/main`;
+		const files: HfModelSibling[] = [];
+
+		let url: string | null =
+			`https://huggingface.co/api/models/${modelId}/tree/main?recursive=true`;
 
 		try {
-			const response = await fetch(url);
+			while (url) {
+				const response: Response = await fetch(url);
 
-			if (!response.ok) return [];
+				if (!response.ok) return files;
 
-			const data = (await response.json()) as HfModelSibling[];
+				const data = (await response.json()) as HfModelSibling[];
 
-			return data.filter((f) => f.type !== 'directory');
+				files.push(...data.filter((f) => f.type !== 'directory'));
+
+				url = HuggingFaceService.parseNextPageUrl(response.headers.get('Link'));
+			}
 		} catch {
-			return [];
+			// Return whatever was fetched before the failure.
 		}
+
+		return files;
 	}
+
 	/**
 	 * Get trending GGUF models
 	 */
@@ -554,7 +621,6 @@ export class HuggingFaceService {
 	): Promise<HfModelInfo[]> {
 		return this.search({ limit, sort: 'trendingScore' });
 	}
-
 	/**
 	 * Parse a local HF cache file path
 	 * (`.../models--<org>--<name>/snapshots/<sha>/<file>`) into its repo id and
@@ -664,8 +730,6 @@ export class HuggingFaceService {
 		return url.toString();
 	}
 
-	// Internal Methods
-
 	/**
 	 * Delay helper for retry logic
 	 */
@@ -673,6 +737,8 @@ export class HuggingFaceService {
 		return new Promise((resolve) => setTimeout(resolve, ms));
 	}
 
+	// Internal Methods
+
 	/**
 	 * Fetch data with retry logic for resilience
 	 */
@@ -719,6 +785,15 @@ export class HuggingFaceService {
 		}
 	}
 
+	/** Extract the `rel="next"` URL from an RFC 5988 `Link` header, if present. */
+	private static parseNextPageUrl(linkHeader: string | null): string | null {
+		if (!linkHeader) return null;
+
+		const match = /<([^>]+)>;\s*rel="next"/.exec(linkHeader);
+
+		return match ? match[1] : null;
+	}
+
 	/** Strip a leading YAML frontmatter block (--- ... ---) from a markdown document. */
 	private static stripFrontmatter(text: string): string {
 		const match = text.match(/^---\r?\n[\s\S]*?\r?\n---\r?\n?/);
diff --git a/tools/ui/src/lib/utils/browser-info.ts b/tools/ui/src/lib/utils/browser-info.ts
index c96abb01e0..e313d42584 100644
--- a/tools/ui/src/lib/utils/browser-info.ts
+++ b/tools/ui/src/lib/utils/browser-info.ts
@@ -16,7 +16,7 @@ import {
 } from '$lib/constants';
 import type { ToolExecutionResult } from '$lib/types';
 
-function detectOs(userAgent: string): string {
+export function detectOs(userAgent: string): string {
 	for (const [pattern, os] of BROWSER_INFO_OS_UA_PATTERNS) {
 		if (pattern.test(userAgent)) return os;
 	}
diff --git a/tools/ui/src/lib/utils/formatters.ts b/tools/ui/src/lib/utils/formatters.ts
index 27555a47be..4739e2150b 100644
--- a/tools/ui/src/lib/utils/formatters.ts
+++ b/tools/ui/src/lib/utils/formatters.ts
@@ -26,24 +26,29 @@ export function formatFileSize(bytes: number | unknown): string {
 }
 
 /**
- * Format parameter count to human-readable format (B, M, K)
+ * Format parameter count to human-readable format (T, B, M, K)
  *
  * @param params - Parameter count
+ * @param decimals - Decimal places to keep (0 rounds to a full number)
  * @returns Human-readable parameter count
  */
-export function formatParameters(params: number | unknown): string {
+export function formatParameters(params: number | unknown, decimals = 2): string {
 	if (typeof params !== 'number') return 'Unknown';
 
+	if (params >= 1e12) {
+		return `${(params / 1e12).toFixed(decimals)}T`;
+	}
+
 	if (params >= 1e9) {
-		return `${(params / 1e9).toFixed(2)}B`;
+		return `${(params / 1e9).toFixed(decimals)}B`;
 	}
 
 	if (params >= 1e6) {
-		return `${(params / 1e6).toFixed(2)}M`;
+		return `${(params / 1e6).toFixed(decimals)}M`;
 	}
 
 	if (params >= 1e3) {
-		return `${(params / 1e3).toFixed(2)}K`;
+		return `${(params / 1e3).toFixed(decimals)}K`;
 	}
 
 	return params.toString();
diff --git a/tools/ui/src/lib/utils/index.ts b/tools/ui/src/lib/utils/index.ts
index 5b2b89c8fb..43e35ec3a1 100644
--- a/tools/ui/src/lib/utils/index.ts
+++ b/tools/ui/src/lib/utils/index.ts
@@ -116,6 +116,14 @@ export {
 	resolveBaseModel
 } from './model-manager';
 
+// Model hardware-compatibility estimation
+export {
+	computeFileCompatibilityTiers,
+	deviceMemoryBudgetMb,
+	resolveDeviceMemoryGb
+} from './model-compatibility';
+export type { CompatibilityTier } from './model-compatibility';
+
 // Portal utilities
 export { portalToBody } from './portal-to-body';
 
@@ -350,7 +358,7 @@ export { buildSandboxToolDefinition, SANDBOX_TOOL_DEFINITION } from './sandbox-t
 export { executeGetDatetimeTool } from './get-datetime';
 
 // Browser fallback for the server's get_info tool
-export { executeBrowserInfoTool } from './browser-info';
+export { detectOs, executeBrowserInfoTool } from './browser-info';
 
 // Cryptography utilities
 
diff --git a/tools/ui/src/lib/utils/model-compatibility.ts b/tools/ui/src/lib/utils/model-compatibility.ts
new file mode 100644
index 0000000000..243b4a3db1
--- /dev/null
+++ b/tools/ui/src/lib/utils/model-compatibility.ts
@@ -0,0 +1,298 @@
+/**
+ * Model hardware-compatibility estimation, ported from ggml-org/llama-macos
+ * (`Model+Compatibility.swift`, `HFRepoResolver.swift`, `SidecarPicker.swift`).
+ *
+ * A quant "fits" when its estimated runtime memory stays within the device
+ * budget. The budget mirrors llama.cpp's own fit target: the GPU working set
+ * (approximated from RAM) minus a fit slack, clamped by an OS floor so the
+ * desktop keeps enough to run. We cannot read Metal's working set from a
+ * browser, so the working set is approximated as 75% of RAM (Apple's ratio on
+ * the machines llama-macos targets).
+ *
+ * Compatibility tiers:
+ * - `full`     -> fits at the model's native max context (green)
+ * - `limited`  -> fits only at a reduced context (yellow)
+ * - `none`     -> does not fit even at the minimum context (red)
+ */
+
+import { browser } from '$app/environment';
+import { HuggingFaceService } from '$lib/services';
+import type { HfModelSibling } from '$lib/types/huggingface';
+
+/** llama.cpp's default `--fit-target` margin, in MB. */
+const FIT_SLACK_MB = 1024;
+/** Physical RAM kept out of a model's reach for the OS and other apps, in MB. */
+const OS_FLOOR_MB = 4096;
+/** Overhead multiplier applied to the file size when estimating weight memory. */
+const WEIGHT_OVERHEAD_MULTIPLIER = 1.05;
+/** Fraction of RAM the GPU working set is approximated as (Apple's ~75%). */
+const WORKING_SET_FRACTION = 0.75;
+/** Minimum context a model must support to launch, matching llama.cpp's default. */
+const MIN_CTX_TOKENS = 4096;
+/** Standard context tiers, ascending, used to find the largest fitting one. */
+const CTX_TIERS = [4096, 8192, 16384, 32768, 65536, 131072, 262144] as const;
+
+export type CompatibilityTier = 'full' | 'limited' | 'none';
+
+const MB = 1024 * 1024;
+/** Hardcoded device RAM (GB) for testing the compatibility UI; 0 disables it. */
+const TEST_DEVICE_MEMORY_GB = 128;
+
+/**
+ * Resolve the device memory in GB: the user's settings override when set,
+ * else the browser's `navigator.deviceMemory` (Chrome/Edge only, capped at 8).
+ * Returns 0 when neither is available, which callers treat as "unknown".
+ */
+export function resolveDeviceMemoryGb(configuredGb: number): number {
+	// Hardcoded device RAM for testing the compatibility UI; 0 disables the
+	// override. TODO: remove once the device-memory source is trusted.
+	if (TEST_DEVICE_MEMORY_GB > 0) return TEST_DEVICE_MEMORY_GB;
+
+	if (configuredGb > 0) return configuredGb;
+
+	if (!browser) return 0;
+
+	const nav = navigator as Navigator & { deviceMemory?: number };
+
+	return typeof nav.deviceMemory === 'number' && nav.deviceMemory > 0 ? nav.deviceMemory : 0;
+}
+
+/**
+ * Memory a model may use, in MB: whichever of the GPU working set (less the
+ * fit slack) or the RAM-less-OS-floor binds first. Returns 0 when unknown.
+ */
+export function deviceMemoryBudgetMb(deviceMemoryGb: number): number {
+	if (deviceMemoryGb <= 0) return 0;
+
+	const physicalMb = deviceMemoryGb * 1024;
+	const gpuLimbMb = physicalMb * WORKING_SET_FRACTION - FIT_SLACK_MB;
+	const ramLimbMb = physicalMb - OS_FLOOR_MB;
+
+	return Math.max(Math.min(gpuLimbMb, ramLimbMb), 0);
+}
+
+/**
+ * Map every GGUF file in the repo to a compatibility tier. Main quants get
+ * their own tier; their shards and sidecars (mmproj + draft head) inherit the
+ * matched main quant's tier so the whole group reads consistently.
+ */
+export function computeFileCompatibilityTiers(
+	files: HfModelSibling[],
+	nativeCtxTokens: number,
+	deviceMemoryGb: number
+): Map<string, CompatibilityTier> {
+	const tiers = new Map<string, CompatibilityTier>();
+
+	// Unknown device memory: leave every file untiered (neutral) rather than
+	// guessing a fit we cannot back up.
+	if (deviceMemoryGb <= 0) return tiers;
+
+	const allPaths = new Set(files.map((f) => f.path));
+	const sizeByPath = new Map(files.map((f) => [f.path, f.size ?? 0]));
+	const budgetMb = deviceMemoryBudgetMb(deviceMemoryGb);
+	// Candidate mains: skip draft heads, mmproj, imatrix, and non-first shards.
+	const mains = files.filter((f) => {
+		const meta = HuggingFaceService.extractQuantMeta(f.path);
+
+		if (!meta || meta.variant !== null) return false;
+
+		if ((f.path.split('/').pop() ?? f.path).toLowerCase().includes('imatrix')) return false;
+
+		return !isNonFirstShard(f.path);
+	});
+	// Track each main's quant bits + directory so draft sidecars can be matched
+	// to their closest-quant main for a tier below.
+	const mainInfos: MainQuantInfo[] = [];
+
+	for (const main of mains) {
+		// Aggregate size: main + shards + mmproj + quant-matched draft.
+		const picked = expandShards(main.path, allPaths);
+		const mmproj = pickSidecar(main.path, files, (v) => v === 'mmproj');
+		const draft = pickSidecar(main.path, files, (v) => v !== null && v !== 'mmproj');
+
+		if (mmproj) picked.push(mmproj.path);
+
+		const mainBytes = picked.reduce((sum, p) => sum + (sizeByPath.get(p) ?? 0), 0);
+		const draftBytes = draft ? (sizeByPath.get(draft.path) ?? 0) : 0;
+		const tier = compatibilityTier(mainBytes + draftBytes, nativeCtxTokens, budgetMb);
+
+		for (const p of picked) tiers.set(p, tier);
+
+		if (draft) tiers.set(draft.path, tier);
+
+		const meta = HuggingFaceService.extractQuantMeta(main.path);
+		const bits = meta?.quant ? (HuggingFaceService.getBitDepth(meta.quant) ?? 0) : 0;
+
+		mainInfos.push({ bits, dirs: dirComponents(main.path), tier });
+	}
+
+	// Assign every remaining draft sidecar (mtp, dflash, ...) the tier of its
+	// closest-quant main, so all variant badges show a fit icon - not just the
+	// single draft counted toward a main's size.
+	for (const file of files) {
+		if (tiers.has(file.path)) continue;
+
+		const meta = HuggingFaceService.extractQuantMeta(file.path);
+
+		if (!meta?.variant || meta.variant === 'mmproj') continue;
+
+		const main = bestMainForSidecar(file.path, meta.quant, mainInfos);
+
+		if (main) tiers.set(file.path, main.tier);
+	}
+
+	return tiers;
+}
+
+interface MainQuantInfo {
+	bits: number;
+	dirs: string[];
+	tier: CompatibilityTier;
+}
+
+/**
+ * Find the main quant a draft sidecar pairs with: among mains in the
+ * sidecar's directory or a descendant of it, the one with the closest quant
+ * bit depth.
+ */
+function bestMainForSidecar(
+	sidecarPath: string,
+	sidecarQuant: string | null,
+	mains: MainQuantInfo[]
+): MainQuantInfo | null {
+	const sidecarDirs = dirComponents(sidecarPath);
+	const sidecarBits = sidecarQuant ? (HuggingFaceService.getBitDepth(sidecarQuant) ?? 0) : 0;
+
+	let best: { diff: number; main: MainQuantInfo } | null = null;
+
+	for (const main of mains) {
+		// The sidecar's directory must be the main's directory or an ancestor.
+		if (sidecarDirs.length > main.dirs.length) continue;
+
+		if (!sidecarDirs.every((d, i) => main.dirs[i] === d)) continue;
+
+		const diff = Math.abs(main.bits - sidecarBits);
+
+		if (!best || diff < best.diff) best = { diff, main };
+	}
+
+	return best?.main ?? null;
+}
+
+/**
+ * Weight memory (MB) is the file size with overhead; context memory scales
+ * with the requested window. A quant is `full` when it fits at the native max
+ * context, `limited` when it only fits at a smaller standard tier, and `none`
+ * when it does not fit even at the minimum context.
+ */
+function compatibilityTier(
+	totalBytes: number,
+	nativeCtxTokens: number,
+	budgetMb: number
+): CompatibilityTier {
+	// A known-but-tiny budget (<= 0) means nothing fits; unknown memory is
+	// handled by the caller returning no tiers at all.
+	const weightMb = (totalBytes / MB) * WEIGHT_OVERHEAD_MULTIPLIER;
+	const ctxBytesPer1k = ctxBytesPer1kTokens(nativeCtxTokens);
+	const fits = (ctxTokens: number) =>
+		weightMb + (ctxBytesPer1k * (ctxTokens / 1000)) / MB <= budgetMb;
+
+	if (nativeCtxTokens < MIN_CTX_TOKENS) return 'none';
+
+	if (fits(nativeCtxTokens)) return 'full';
+
+	// Find the largest standard tier that still fits within the native window.
+	const largestFitting = [...CTX_TIERS]
+		.filter((t) => t <= nativeCtxTokens)
+		.reverse()
+		.find((t) => fits(t));
+
+	return largestFitting !== undefined ? 'limited' : 'none';
+}
+
+/**
+ * Approximate KV-cache bytes per 1k tokens. Without a MemProfile probe (which
+ * only exists post-launch in llama-macos) we estimate from the native context
+ * window; ~0.1 MB per 1k tokens is a conservative mid-range for modern models.
+ */
+function ctxBytesPer1kTokens(_nativeCtxTokens: number): number {
+	return 0.1 * MB;
+}
+
+/** Directory components of a repo-relative path (`Q4_K_M/a.gguf` -> `["Q4_K_M"]`). */
+function dirComponents(path: string): string[] {
+	return path.split('/').slice(0, -1);
+}
+
+/** True for a split-shard continuation (`-00002-of-00003.gguf`), not the first shard. */
+function isNonFirstShard(path: string): boolean {
+	const match = /-(\d{5})-of-(\d{5})\.gguf$/i.exec(path);
+
+	return match !== null && match[1] !== '00001';
+}
+
+/** Expand a main GGUF to its full shard set; non-sharded files return `[main]`. */
+function expandShards(main: string, allPaths: Set<string>): string[] {
+	const match = /-(\d{5})-of-(\d{5})\.gguf$/i.exec(main);
+
+	if (!match) return [main];
+
+	const total = parseInt(match[2], 10);
+	const stem = main.slice(0, main.length - match[0].length);
+	const shards: string[] = [];
+
+	for (let i = 1; i <= total; i++) {
+		const shard = `${stem}-${String(i).padStart(5, '0')}-of-${String(total).padStart(5, '0')}.gguf`;
+
+		if (allPaths.has(shard)) shards.push(shard);
+	}
+
+	return shards.length > 0 ? shards : [main];
+}
+
+/**
+ * Pick the best sidecar (mmproj or draft head) for a main file, mirroring
+ * llama.cpp's `find_best_sibling`: the candidate's directory must be the main
+ * file's directory or an ancestor; candidates rank by deepest directory, then
+ * exact quant-tag match, then closest quant-bit distance.
+ */
+function pickSidecar(
+	main: string,
+	files: HfModelSibling[],
+	isCandidate: (variant: string | null) => boolean
+): HfModelSibling | null {
+	const mainDirs = dirComponents(main);
+	const mainMeta = HuggingFaceService.extractQuantMeta(main);
+	const mainBits = mainMeta?.quant ? (HuggingFaceService.getBitDepth(mainMeta.quant) ?? 0) : 0;
+	const mainTag = mainMeta?.quant?.toUpperCase();
+
+	let best: { depth: number; diff: number; exact: boolean; file: HfModelSibling } | null = null;
+
+	for (const file of files) {
+		const meta = HuggingFaceService.extractQuantMeta(file.path);
+
+		if (!meta || !isCandidate(meta.variant)) continue;
+
+		const dirs = dirComponents(file.path);
+
+		if (dirs.length > mainDirs.length || !dirs.every((d, i) => mainDirs[i] === d)) continue;
+
+		const depth = dirs.length;
+		const bits = meta.quant ? (HuggingFaceService.getBitDepth(meta.quant) ?? 0) : 0;
+		const diff = Math.abs(bits - mainBits);
+		const exact = mainTag ? file.path.toUpperCase().includes(`-${mainTag}.`) : false;
+
+		if (best) {
+			const better =
+				depth > best.depth ||
+				(depth === best.depth && exact && !best.exact) ||
+				(depth === best.depth && exact === best.exact && diff < best.diff);
+
+			if (!better) continue;
+		}
+
+		best = { depth, diff, exact, file };
+	}
+
+	return best?.file ?? null;
+}