diff --git a/web/src/lib/components/kit/SchemaFields.svelte b/web/src/lib/components/kit/SchemaFields.svelte
new file mode 100644
index 0000000..bc3b232
--- /dev/null
+++ b/web/src/lib/components/kit/SchemaFields.svelte
@@ -0,0 +1,134 @@
+<script lang="ts">
+	import { RotateCcw } from "@lucide/svelte";
+	import type { ToolSchema } from "$lib/registry-schema";
+
+	interface Props {
+		schema: ToolSchema<Record<string, unknown>>;
+		values: Record<string, unknown>;
+		onchange: (id: string, value: unknown) => void;
+		onreset: () => void;
+	}
+	let { schema, values, onchange, onreset }: Props = $props();
+
+	function labelOf(id: string): string {
+		return id
+			.replace(/([a-z])([A-Z])/g, "$1 $2")
+			.replace(/[_-]+/g, " ")
+			.replace(/\b\w/g, (c) => c.toUpperCase());
+	}
+</script>
+
+{#each Object.entries(schema.fields) as [id, field] (id)}
+	{#if field.spec.kind === "number" || field.spec.kind === "slider"}
+		<label class="control">
+			<span>
+				{labelOf(id)}
+				<output>{String(values[id] ?? field.spec.default)}</output>
+			</span>
+			<input
+				type="range"
+				min={field.spec.min ?? 0}
+				max={field.spec.max ?? 100}
+				step={field.spec.step ?? 1}
+				value={Number(values[id] ?? field.spec.default)}
+				oninput={(e) =>
+					onchange(id, Number((e.target as HTMLInputElement).value))}
+			/>
+		</label>
+	{:else if field.spec.kind === "color"}
+		<label class="control color-control">
+			<span>{labelOf(id)}</span>
+			<span class="color-row">
+				<span
+					class="swatch"
+					style="background:{String(values[id] ?? field.spec.default)}"
+				></span>
+				<input
+					type="color"
+					value={String(values[id] ?? field.spec.default)}
+					oninput={(e) => onchange(id, (e.target as HTMLInputElement).value)}
+				/>
+			</span>
+		</label>
+	{/if}
+{/each}
+
+<div class="panel-foot">
+	<button class="reset-btn" onclick={onreset}>
+		<RotateCcw size={14} /> Reset
+	</button>
+	<span class="auto-note"><i></i> updates automatically</span>
+</div>
+
+<style>
+	.control {
+		display: grid;
+		gap: var(--space-m);
+		margin-bottom: var(--space-xl);
+		color: var(--color-text-muted);
+		font: var(--font-size-s) var(--font-mono);
+		letter-spacing: var(--space-text-m);
+	}
+	.control > span {
+		display: flex;
+		justify-content: space-between;
+	}
+	.control output {
+		color: var(--color-text);
+	}
+	input[type="range"] {
+		width: 100%;
+		accent-color: var(--color-main);
+		color: var(--color-text);
+	}
+	.color-control > span:first-child {
+		justify-content: flex-start;
+	}
+	.color-row {
+		display: flex;
+		align-items: center;
+		gap: var(--space-m);
+	}
+	.swatch {
+		width: var(--space-xxl);
+		height: var(--space-xxl);
+		border-radius: var(--radius-s);
+		border: var(--size-border) solid var(--color-border);
+	}
+	input[type="color"] {
+		width: 100%;
+		height: var(--space-xxl);
+		border: var(--size-border) solid var(--color-border);
+		border-radius: var(--radius-s);
+		background: var(--color-background);
+		cursor: pointer;
+	}
+	.panel-foot {
+		display: flex;
+		justify-content: space-between;
+		align-items: center;
+		gap: var(--space-m);
+		margin-top: var(--space-xl);
+		padding-top: var(--space-l);
+		border-top: var(--size-border) solid var(--color-border);
+	}
+	.reset-btn {
+		display: inline-flex;
+		align-items: center;
+		gap: var(--space-m);
+		background: none;
+		border: none;
+		color: var(--color-text-muted);
+		font: var(--font-size-s) var(--font-mono);
+		cursor: pointer;
+	}
+	.reset-btn:hover {
+		color: var(--color-text);
+	}
+	.auto-note i {
+		width: var(--size-border-thick);
+		height: var(--size-border-thick);
+		border-radius: 50%;
+		background: var(--color-success);
+	}
+</style>
diff --git a/web/src/lib/components/kit/SchemaPreview.svelte b/web/src/lib/components/kit/SchemaPreview.svelte
new file mode 100644
index 0000000..77fa39c
--- /dev/null
+++ b/web/src/lib/components/kit/SchemaPreview.svelte
@@ -0,0 +1,174 @@
+<script lang="ts">
+	import { Check, Upload } from "@lucide/svelte";
+	import { toDataUrl } from "$lib/core/io";
+	import type { PixelImage } from "$lib/core/types";
+	import MetaList from "$lib/components/kit/MetaList.svelte";
+	import DownloadButton from "$lib/components/kit/ui/DownloadButton.svelte";
+
+	interface Props {
+		source: PixelImage | null;
+		result: PixelImage | null;
+		running: boolean;
+		error: string;
+		onupload: (file: File) => void;
+		ondownload: () => void;
+	}
+	let { source, result, running, error, onupload, ondownload }: Props =
+		$props();
+
+	let sourceUrl = $derived(source ? toDataUrl(source) : null);
+	let resultUrl = $derived(result ? toDataUrl(result) : null);
+</script>
+
+<div class="panel-head">
+	<span class="label">SOURCE / RESULT</span>
+	<div class="head-actions">
+		<label class="upload">
+			<Upload size={14} /> Open image
+			<input
+				type="file"
+				accept="image/*"
+				onchange={(e) => {
+					const f = (e.target as HTMLInputElement).files?.[0];
+					if (f) onupload(f);
+				}}
+			/>
+		</label>
+		<DownloadButton label="Download result" onclick={ondownload} />
+	</div>
+</div>
+
+{#if error}
+	<p class="error" role="alert">{error}</p>
+{/if}
+
+<div class="pair">
+	<figure class="tile">
+		<figcaption><span>SOURCE</span></figcaption>
+		<div class="canvas">
+			{#if sourceUrl}
+				<img src={sourceUrl} alt="source" />
+			{:else}
+				<span class="empty">choose an image</span>
+			{/if}
+		</div>
+	</figure>
+	<figure class="tile">
+		<figcaption><span>RESULT {running ? "…" : ""}</span></figcaption>
+		<div class="canvas checker">
+			{#if resultUrl}
+				<img src={resultUrl} alt="result" />
+			{:else if running}
+				<Check size={22} />
+			{:else}
+				<span class="empty">no result yet</span>
+			{/if}
+		</div>
+	</figure>
+</div>
+
+<div class="meta">
+	<MetaList
+		items={[
+			{
+				caption: "SOURCE",
+				value: source ? `${source.width} × ${source.height} px` : "—",
+			},
+			{
+				caption: "RESULT",
+				value: result ? `${result.width} × ${result.height} px` : "—",
+			},
+			{ caption: "FORMAT", value: "PNG" },
+		]}
+	/>
+</div>
+
+<style>
+	.panel-head {
+		display: flex;
+		justify-content: space-between;
+		align-items: baseline;
+		gap: var(--space-m);
+		padding-bottom: var(--space-l);
+		border-bottom: var(--size-border) solid var(--color-border);
+		margin-bottom: var(--space-xl);
+	}
+	.label {
+		font: var(--font-size-s) var(--font-mono);
+		letter-spacing: var(--space-text-l);
+		color: var(--color-main);
+	}
+	.head-actions {
+		display: flex;
+		align-items: center;
+		gap: var(--space-l);
+		flex-wrap: wrap;
+	}
+	.upload {
+		display: inline-flex;
+		align-items: center;
+		gap: var(--space-m);
+		padding: var(--space-m) var(--space-l);
+		border: var(--size-border) solid var(--color-border);
+		border-radius: var(--radius-m);
+		font: var(--font-size-s) var(--font-mono);
+		color: var(--color-text-muted);
+		cursor: pointer;
+	}
+	.upload input {
+		display: none;
+	}
+	.error {
+		margin: 0 0 var(--space-l);
+		color: var(--color-danger);
+		font: var(--font-size-s) var(--font-mono);
+	}
+	.pair {
+		display: grid;
+		grid-template-columns: 1fr 1fr;
+		gap: var(--space-l);
+	}
+	.tile figcaption {
+		display: flex;
+		align-items: center;
+		gap: var(--space-m);
+		margin-bottom: var(--space-m);
+		font: var(--font-size-s) var(--font-mono);
+		color: var(--color-text-muted);
+	}
+	.canvas {
+		display: flex;
+		align-items: center;
+		justify-content: center;
+		min-height: clamp(var(--space-brand), 30vh, 60vh);
+		border: var(--size-border) solid var(--color-border);
+		border-radius: var(--radius-m);
+		overflow: hidden;
+		background: var(--color-background-muted);
+		color: var(--color-text-muted);
+	}
+	.canvas img {
+		width: 100%;
+		height: 100%;
+		object-fit: contain;
+		display: block;
+	}
+	.canvas.checker {
+		background: repeating-conic-gradient(
+				var(--color-checker-main) 0 25%,
+				var(--color-checker-alt) 0 50%
+			)
+			50% / 28px 28px;
+	}
+	.empty {
+		font: var(--font-size-s) var(--font-mono);
+	}
+	.meta {
+		margin-top: var(--space-l);
+	}
+	@media (max-width: var(--bp-tablet)) {
+		.pair {
+			grid-template-columns: 1fr;
+		}
+	}
+</style>
diff --git a/web/src/lib/components/kit/SchemaToolView.svelte b/web/src/lib/components/kit/SchemaToolView.svelte
new file mode 100644
index 0000000..50c2437
--- /dev/null
+++ b/web/src/lib/components/kit/SchemaToolView.svelte
@@ -0,0 +1,216 @@
+<script lang="ts">
+	import { decodeFile, encode } from "$lib/core/io";
+	import { debounce } from "$lib/core/debounce";
+	import type { PixelImage } from "$lib/core/types";
+	import {
+		defaultSchemaParams,
+		sanitizeSchemaParams,
+		type ToolSchema,
+	} from "$lib/registry-schema";
+	import { executeStep } from "$lib/tools/executor";
+	import type { ToolEntry } from "$lib/registry";
+	import SchemaFields from "$lib/components/kit/SchemaFields.svelte";
+	import SchemaPreview from "$lib/components/kit/SchemaPreview.svelte";
+
+	interface Props {
+		tool: ToolEntry;
+	}
+	let { tool }: Props = $props();
+
+	const schema = $derived(
+		tool.schema as ToolSchema<Record<string, unknown>> | undefined,
+	);
+
+	let values = $state<Record<string, unknown>>({});
+	let source = $state<PixelImage | null>(null);
+	let result = $state<PixelImage | null>(null);
+	let running = $state(false);
+	let error = $state("");
+	let started = $state(false);
+
+	const debouncedRun = debounce(() => run(), 200);
+
+	function init() {
+		if (!schema || started) return;
+		started = true;
+		values = defaultSchemaParams(schema);
+	}
+
+	function setValue(id: string, value: unknown) {
+		values = { ...values, [id]: value };
+	}
+
+	function reset() {
+		values = schema ? defaultSchemaParams(schema) : {};
+		result = null;
+		error = "";
+	}
+
+	async function handleFile(file: File) {
+		error = "";
+		try {
+			source = await decodeFile(file);
+		} catch (e) {
+			error = errorText(e);
+		}
+	}
+
+	async function run() {
+		if (!schema || !tool.run || !source) return;
+		running = true;
+		error = "";
+		const params = sanitizeSchemaParams(schema, values);
+		try {
+			result = await executeStep(tool, source, params);
+		} catch (e) {
+			error = errorText(e);
+		} finally {
+			running = false;
+		}
+	}
+
+	async function download() {
+		if (!result) return;
+		const blob = await encode(result, "image/png");
+		const url = URL.createObjectURL(blob);
+		const a = document.createElement("a");
+		a.href = url;
+		a.download = "with-border.png";
+		a.click();
+		URL.revokeObjectURL(url);
+	}
+
+	$effect(() => {
+		init();
+	});
+
+	$effect(() => {
+		if (!source || !started) return;
+		void values;
+		debouncedRun();
+		return () => debouncedRun.cancel();
+	});
+
+	function errorText(e: unknown): string {
+		return e instanceof Error ? e.message : String(e);
+	}
+</script>
+
+{#if schema}
+	<div class="schema-tool">
+		<header class="header">
+			<div class="title-block">
+				<span class="eyebrow">PNG PROCESSING <span>/</span> SINGLE TOOL</span>
+				<h1>{tool.title}</h1>
+				<p class="lede">{tool.description}</p>
+			</div>
+			<span class="status"><i></i> LIVE PREVIEW</span>
+		</header>
+
+		<div class="workspace">
+			<section class="panel settings">
+				<div class="panel-head">
+					<span class="label">TOOL SETTINGS</span>
+					<strong>Configure output</strong>
+				</div>
+				<SchemaFields {schema} {values} onchange={setValue} onreset={reset} />
+			</section>
+
+			<section class="panel">
+				<SchemaPreview
+					{source}
+					{result}
+					{running}
+					{error}
+					onupload={handleFile}
+					ondownload={download}
+				/>
+			</section>
+		</div>
+	</div>
+{:else}
+	<p class="no-schema">This tool has no schema yet.</p>
+{/if}
+
+<style>
+	.schema-tool {
+		padding: calc(var(--space-xxxl) + var(--space-l))
+			clamp(var(--space-m), 4vw, var(--space-xxxl));
+	}
+	.header {
+		display: flex;
+		justify-content: space-between;
+		gap: var(--space-l);
+		margin-bottom: var(--space-xxxl);
+	}
+	.title-block h1 {
+		margin: var(--space-s) 0 0;
+		font-size: clamp(var(--font-size-xl), 4vw, var(--font-size-2xl));
+		line-height: 1.1;
+		color: var(--color-text);
+	}
+	.eyebrow,
+	.label,
+	.status {
+		font: var(--font-size-s) var(--font-mono);
+		letter-spacing: var(--space-text-l);
+		color: var(--color-text-muted);
+	}
+	.eyebrow span,
+	.label {
+		color: var(--color-main);
+	}
+	.lede {
+		max-width: 100%;
+		margin: var(--space-m) 0 0;
+		color: var(--color-text-muted);
+		font-size: var(--font-size-s);
+		line-height: 1.5;
+	}
+	.status {
+		display: inline-flex;
+		align-items: center;
+		gap: var(--space-m);
+		align-self: flex-start;
+		white-space: nowrap;
+	}
+	.status i {
+		width: var(--size-border-thick);
+		height: var(--size-border-thick);
+		border-radius: 50%;
+		background: var(--color-success);
+	}
+	.workspace {
+		display: grid;
+		grid-template-columns: minmax(260px, 1fr) minmax(0, 2fr);
+		gap: var(--space-xxl);
+		align-items: start;
+	}
+	.panel {
+		border: var(--size-border) solid var(--color-border);
+		border-radius: var(--radius-m);
+		background: var(--color-panel);
+		padding: var(--space-xl);
+	}
+	.panel-head {
+		display: flex;
+		justify-content: space-between;
+		align-items: baseline;
+		gap: var(--space-m);
+		padding-bottom: var(--space-l);
+		border-bottom: var(--size-border) solid var(--color-border);
+		margin-bottom: var(--space-xl);
+	}
+	.panel-head strong {
+		font-size: var(--font-size-l);
+		color: var(--color-text);
+	}
+	.no-schema {
+		font: var(--font-size-s) var(--font-mono);
+	}
+	@media (max-width: var(--bp-tablet)) {
+		.workspace {
+			grid-template-columns: 1fr;
+		}
+	}
+</style>
diff --git a/web/src/lib/core/debounce.ts b/web/src/lib/core/debounce.ts
new file mode 100644
index 0000000..0efc07e
--- /dev/null
+++ b/web/src/lib/core/debounce.ts
@@ -0,0 +1,17 @@
+export function debounce(
+	fn: () => void,
+	ms: number,
+): { (): void; cancel: () => void } {
+	let timer: ReturnType<typeof setTimeout> | undefined;
+
+	const debounced = () => {
+		if (timer !== undefined) clearTimeout(timer);
+		timer = setTimeout(() => fn(), ms);
+	};
+
+	debounced.cancel = () => {
+		if (timer !== undefined) clearTimeout(timer);
+	};
+
+	return debounced;
+}
diff --git a/web/src/preview.css b/web/src/preview.css
index cc0c572..0af34b1 100644
--- a/web/src/preview.css
+++ b/web/src/preview.css
@@ -144,9 +144,15 @@
 		--font-size-s: 12px;
 		--font-size-m: 14px;
 		--font-size-l: 16px;
+		--font-size-xl: 24px;
+		--font-size-2xl: 32px;
 
 		--radius-s: 0px;
 		--radius-m: 4px;
+
+		--bp-mobile: 640px;
+		--bp-tablet: 800px;
+		--bp-desktop: 1100px;
 	}
 
 	[data-theme="dark"] {
diff --git a/web/src/routes/preview/tools/[id]/+page.svelte b/web/src/routes/preview/tools/[id]/+page.svelte
index 42ce9ea..8d3af18 100644
--- a/web/src/routes/preview/tools/[id]/+page.svelte
+++ b/web/src/routes/preview/tools/[id]/+page.svelte
@@ -1,6 +1,7 @@
 <script lang="ts">
 	import { getTool } from "$lib/registry";
 	import ToolView from "$lib/components/kit/ToolView.svelte";
+	import SchemaToolView from "$lib/components/kit/SchemaToolView.svelte";
 	import EmptyState from "$lib/components/kit/EmptyState.svelte";
 	import { SlidersHorizontal as ToolIcon } from "@lucide/svelte";
 
@@ -25,6 +26,8 @@
 			icon={ToolIcon}
 		/>
 	</div>
+{:else if tool.schema}
+	<SchemaToolView {tool} />
 {:else}
 	<ToolView {tool} />
 {/if}