diff --git a/scripts/soma-attr-audit.ts b/scripts/soma-attr-audit.ts
new file mode 100644
index 000000000..80be47e9d
--- /dev/null
+++ b/scripts/soma-attr-audit.ts
@@ -0,0 +1,120 @@
+/**
+ * Soma ↔ morfo attribute-duplication audit.
+ *
+ * "Morfo declares, soma executes." A provider should not re-declare in its
+ * `props` getter an attr the morfo already declares with a resolvable value —
+ * spread `runtimePart.renderProps()` instead. This script flags every such
+ * duplication so the migration backlog is measurable and new drift is caught.
+ *
+ * For each morfo at `src/uix/morfo/components/*.ts`:
+ *   1. compile it → per part, the set of attrs it declares WITH a value
+ *      (compiled staticAttrs + dynamicAttrs; no-value contract attrs like a
+ *      bare `data-disabled` are excluded — those are legitimately soma-owned).
+ *   2. read the matching soma provider, split it into segments by each
+ *      `runtime.part('<kebab>', …)` call, and scan each segment for hardcoded
+ *      attr literals (`role:` / `type:` / `'aria-*':` / `'data-*':`).
+ *   3. report (component · part · attr) where the attr is BOTH hardcoded AND
+ *      morfo-declared.
+ *
+ * Some hits are legitimate value overrides (e.g. a locale-formatted
+ * `aria-valuetext` over the morfo's raw value) — those are reviewed during the
+ * rollout. The number trends to zero as providers adopt `renderProps()`.
+ *
+ * Usage: `npx tsx scripts/soma-attr-audit.ts [--component <kebab>]`
+ */
+import { readdirSync, readFileSync, existsSync } from 'node:fs'
+import { join } from 'node:path'
+import { pathToFileURL } from 'node:url'
+import { compileMorfo } from '../src/uix/morfo/compile'
+import type { Morfo } from '../src/uix/morfo/types'
+
+const MORFOS_DIR = 'src/uix/morfo/components'
+const SOMA_DIR = 'src/uix/soma/components'
+const ATTR_KEY = /^\s*'?(role|type|aria-[a-z-]+|data-[a-z-]+)'?\s*:/
+const PART_CALL = /runtime\.part\(\s*'([a-z-]+)'/g
+
+export async function loadMorfos(): Promise<Morfo[]> {
+	const out: Morfo[] = []
+	for (const f of readdirSync(MORFOS_DIR).filter((f) => f.endsWith('.ts') && !f.endsWith('.test.ts'))) {
+		const mod = (await import(pathToFileURL(join(MORFOS_DIR, f)).href)) as Record<string, unknown>
+		for (const v of Object.values(mod)) {
+			if (typeof v === 'object' && v !== null && 'kebab' in v && 'parts' in v) out.push(v as Morfo)
+		}
+	}
+	return out
+}
+
+/** Attrs the compiled part declares with a resolvable value (excludes no-value contract attrs). */
+function declaredAttrs(morfo: Morfo, partKebab: string): Set<string> {
+	const compiled = compileMorfo(morfo)
+	const part = compiled.parts.byKebab.get(partKebab) as
+		| { staticAttrs?: Record<string, unknown>; dynamicAttrs?: { attr: string }[] }
+		| undefined
+	const set = new Set<string>()
+	if (!part) return set
+	for (const k of Object.keys(part.staticAttrs ?? {})) set.add(k)
+	for (const d of part.dynamicAttrs ?? []) set.add(d.attr)
+	return set
+}
+
+/** Read every provider source file for a component (glob `*-provider.svelte.ts`). */
+function providerSources(kebab: string): string {
+	const dir = join(SOMA_DIR, kebab)
+	if (!existsSync(dir)) return ''
+	return readdirSync(dir)
+		.filter((f) => f.endsWith('-provider.svelte.ts'))
+		.map((f) => readFileSync(join(dir, f), 'utf8'))
+		.join('\n')
+}
+
+type Hit = { component: string; part: string; attr: string }
+
+export function auditComponent(morfo: Morfo): Hit[] {
+	const src = providerSources(morfo.kebab)
+	if (!src) return []
+	// Segment the source by `runtime.part('X')`: each segment's hardcoded attrs
+	// belong to part X (the props getter sits between this call and the next).
+	const calls = [...src.matchAll(PART_CALL)]
+	if (calls.length === 0) return []
+	const hits: Hit[] = []
+	for (let i = 0; i < calls.length; i++) {
+		const partKebab = calls[i][1]
+		const start = calls[i].index ?? 0
+		const end = i + 1 < calls.length ? (calls[i + 1].index ?? src.length) : src.length
+		const segment = src.slice(start, end)
+		const declared = declaredAttrs(morfo, partKebab)
+		if (declared.size === 0) continue
+		for (const line of segment.split('\n')) {
+			const m = ATTR_KEY.exec(line)
+			if (m && declared.has(m[1])) hits.push({ component: morfo.kebab, part: partKebab, attr: m[1] })
+		}
+	}
+	return hits
+}
+
+async function main() {
+	const onlyArg = process.argv.indexOf('--component')
+	const only = onlyArg >= 0 ? process.argv[onlyArg + 1] : undefined
+	const morfos = (await loadMorfos()).filter((m) => !only || m.kebab === only)
+
+	const byComponent = new Map<string, Hit[]>()
+	for (const m of morfos) {
+		const hits = auditComponent(m)
+		if (hits.length) byComponent.set(m.kebab, hits)
+	}
+
+	const total = [...byComponent.values()].reduce((n, h) => n + h.length, 0)
+	const sorted = [...byComponent.entries()].sort((a, b) => b[1].length - a[1].length)
+
+	console.log(`\nSoma↔morfo attr duplication — ${total} hits across ${byComponent.size} components\n`)
+	for (const [component, hits] of sorted) {
+		const byPart = new Map<string, string[]>()
+		for (const h of hits) (byPart.get(h.part) ?? byPart.set(h.part, []).get(h.part)!).push(h.attr)
+		console.log(`  ${component}  (${hits.length})`)
+		for (const [part, attrs] of byPart) console.log(`    ${part}: ${attrs.join(', ')}`)
+	}
+	console.log('')
+}
+
+// Run only when invoked directly (`tsx scripts/soma-attr-audit.ts`), not on import.
+if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href) main()
diff --git a/src/uix/soma/soma-attr-audit.test.ts b/src/uix/soma/soma-attr-audit.test.ts
new file mode 100644
index 000000000..c8c7761a3
--- /dev/null
+++ b/src/uix/soma/soma-attr-audit.test.ts
@@ -0,0 +1,45 @@
+import { describe, it, expect } from 'vitest';
+
+import { loadMorfos, auditComponent } from '../../../scripts/soma-attr-audit';
+
+/**
+ * Regression guard for the morfo↔soma attr de-duplication migration.
+ *
+ * A migrated provider sources its role/aria/data from `runtimePart.renderProps()`
+ * and must not re-declare them. The only hits that may remain are LEGITIMATE
+ * value overrides the morfo can't express (a locale-formatted `aria-valuetext`,
+ * a parsed `aria-valuenow`). This test pins each migrated component to its
+ * legit-override ceiling so it can't silently drift back to hardcoded attrs.
+ *
+ * As a component is migrated, add it here with its ceiling (run
+ * `npx tsx scripts/soma-attr-audit.ts --component <kebab>` to see the residue).
+ * The full backlog for not-yet-migrated components lives in the script output.
+ */
+const MIGRATED_CEILINGS: Record<string, number> = {
+	'number-field': 1, // input: aria-valuetext (formatted)
+	'css-field': 2 // input: aria-valuenow (parsed) + aria-valuetext
+};
+
+describe('soma↔morfo attr de-dup guard', () => {
+	it('migrated providers re-declare no morfo attrs beyond their legit value overrides', async () => {
+		const morfos = await loadMorfos();
+		const violations: string[] = [];
+
+		for (const [kebab, ceiling] of Object.entries(MIGRATED_CEILINGS)) {
+			const morfo = morfos.find((m) => m.kebab === kebab);
+			if (!morfo) {
+				violations.push(`${kebab}: morfo not found`);
+				continue;
+			}
+			const hits = auditComponent(morfo);
+			if (hits.length > ceiling) {
+				violations.push(
+					`${kebab}: ${hits.length} hits (ceiling ${ceiling}) — ` +
+						hits.map((h) => `${h.part}.${h.attr}`).join(', ')
+				);
+			}
+		}
+
+		expect(violations).toEqual([]);
+	});
+});