diff --git a/apps/api/src/openapi.ts b/apps/api/src/openapi.ts
index c694e80..c05009b 100644
--- a/apps/api/src/openapi.ts
+++ b/apps/api/src/openapi.ts
@@ -668,6 +668,43 @@ export const UpdateInventionMetadataRequest = z.object({
 		.describe('Replaces both lists wholesale, as `v1/settags` does; null leaves them alone'),
 })
 
+/**
+ * `POST /api/inventions/v2/update` JSON body — the newer client's counterpart to
+ * `v1/update`'s query string. PascalCase, and nullable the way `v2/metadata`'s is: a null
+ * field keeps what the invention already has, so this is a patch rather than a replace.
+ *
+ * Only `InventionId` and `Permission` are confirmed from a live capture (the permission
+ * picker sends exactly those two). The rest are accepted defensively — they are the fields
+ * `v1/update` took that `v2/metadata` does not — so that a build sending one gets it
+ * applied instead of silently dropped.
+ */
+export const UpdateInventionRequest = z.object({
+	InventionId: z.int(),
+	Permission: z
+		.int()
+		.nullable()
+		.optional()
+		.describe(
+			'The `GeneralPermission` other players get, as a raw ladder number: Unassigned 0, ' +
+				'LimitedOneUseOnly 10, DisallowKeyLock 15, UseOnly 20, EditAndSave 40, Publish 60, ' +
+				'Charge 80, Unlimited 100. Unlike `v4/publish`, null LEAVES IT ALONE rather than ' +
+				'falling back to UseOnly — an edit that names no permission is not a demotion'
+		),
+	AllowTrial: z
+		.boolean()
+		.nullable()
+		.optional()
+		.describe('Whether other players may trial it; null leaves it alone'),
+	Name: z
+		.string()
+		.nullable()
+		.optional()
+		.describe('3–24 chars, letters/digits/spaces/dashes/colons; null leaves it alone'),
+	Description: z.string().nullable().optional().describe('Max 512 chars; empty clears it'),
+	LongDescription: z.string().nullable().optional().describe('Empty clears it'),
+	ImageName: z.string().nullable().optional().describe('New thumbnail; empty clears it'),
+})
+
 /**
  * `POST /api/inventions/v4/publish` JSON body — PascalCase, and nullable the way
  * `v2/metadata`'s is: a null field keeps what the invention already has.
diff --git a/apps/api/src/routes/avatar.ts b/apps/api/src/routes/avatar.ts
index f476d0b..c2cea1a 100644
--- a/apps/api/src/routes/avatar.ts
+++ b/apps/api/src/routes/avatar.ts
@@ -104,6 +104,7 @@ import {
 	UNAUTHORIZED_RESPONSE,
 	UpdateCustomAvatarItemRequest,
 	UpdateInventionMetadataRequest,
+	UpdateInventionRequest,
 	UpdatePriceRequest,
 } from '../openapi'
 import { createReport } from '../reports-db'
@@ -2055,6 +2056,112 @@ export const avatarRoutes = new Hono<App>({ strict: false })
 		}
 	)
 
+	// Edit an invention, as the newer client sends it: the `v1/update` write with a
+	// PascalCase body instead of a query string. What the permission picker posts —
+	// `{ InventionId, Permission }` — and so the endpoint that changes what other players
+	// may DO with an invention, where `v2/metadata` beside it changes what it SAYS.
+	//
+	// Creator only, which is the whole point of the gate: `GeneralPermission` is what lets
+	// another player edit, re-publish or charge for someone's build, so a write that took
+	// the caller's word for the id would let anyone hand themselves rights over any
+	// invention in the game.
+	.post(
+		'/api/inventions/v2/update',
+		describeRoute({
+			tags: ['Inventions'],
+			summary: 'Edit an invention (v2)',
+			description:
+				'The newer client’s form of `v1/update`: a PascalCase JSON body in place of the ' +
+				'query string. A patch, not a replace — every field but `InventionId` is nullable ' +
+				'and a null one is left as it is, since the client sends the whole shape on every ' +
+				'edit.\n\n' +
+				'**Creator only.** `Permission` decides what other players may do with the ' +
+				'invention — up to editing, re-publishing and charging for it — so only the ' +
+				'account that created it may set it.\n\n' +
+				'`Permission` is the raw `GeneralPermission` ladder number (UseOnly 20, ' +
+				'EditAndSave 40, Publish 60 …), stored verbatim and unmapped, exactly as ' +
+				'`v1/update` stores the value its picker names. A null one LEAVES IT ALONE — ' +
+				'unlike `v4/publish`, where null means UseOnly: publishing something with no ' +
+				'permission named is a decision, but editing it without naming one is not.\n\n' +
+				'Publishing, pricing and tags are elsewhere (`v4/publish`, `v1/updateprice`, ' +
+				'`v2/metadata`), as they are for `v1/update`.\n\n' +
+				'Answers the enveloped result `v9/save` answers, carrying the UPDATED invention: ' +
+				'the client re-renders the detail sheet from `Value.Invention`, so a refusal — an ' +
+				'unknown invention and someone else’s alike — is `Success: false` with a null ' +
+				'`Value` rather than a bare error body, which that client cannot parse.',
+			security: AUTHED,
+			requestBody: jsonBody(UpdateInventionRequest, 'The fields to change'),
+			responses: {
+				200: json(
+					InventionSaveV9Result,
+					'The envelope — the updated invention under `Value`, or `Success: false` with ' +
+						'`Error` when the edit was refused'
+				),
+				401: json(InventionSaveV9Result, 'The same envelope, refused — not an empty body'),
+			},
+		}),
+		async (c) => {
+			const body = (await c.req.json().catch(() => null)) as Record<string, unknown> | null
+			if (body === null) return c.json(inventionSaveV9Failure('Invalid request body'))
+
+			// The id rides in the body here, not the query string. The gate is what makes this
+			// creator-only: it loads the invention and refuses anyone but the account that
+			// created it.
+			const gate = await creatorsInventionResult(
+				c,
+				typeof body.InventionId === 'number' ? body.InventionId : Number.NaN
+			)
+			// Only a missing token is answered as a transport failure. An unknown invention or
+			// someone else's is a domain answer this client is meant to read — its own status
+			// enum has DoesNotExist and NotCreator members — so it goes in the envelope, where
+			// the message reaches a human. Same split `v2/metadata` makes.
+			if ('rejection' in gate) {
+				return gate.status === 401
+					? c.json(inventionSaveV9Failure(gate.rejection), 401)
+					: c.json(inventionSaveV9Failure(gate.rejection))
+			}
+
+			// A number is the picker's own form; a string is accepted through the same parser
+			// `v1/update`'s query param goes through, so a build sending `"EditAndSave"` or
+			// `"40"` lands on the same level. Anything else (null included) leaves it alone.
+			const permission =
+				typeof body.Permission === 'number'
+					? body.Permission
+					: typeof body.Permission === 'string'
+						? parsePermissionLevel(body.Permission)
+						: undefined
+
+			// Null is "leave it"; a string, empty or not, is an edit — `v2/metadata`'s rule,
+			// since these are the same client's bodies.
+			const edited = (key: string): string | undefined =>
+				typeof body[key] === 'string' ? body[key] : undefined
+			const name = edited('Name')?.trim()
+			const description = edited('Description')
+			const longDescription = edited('LongDescription')
+
+			for (const rejection of [
+				name === undefined ? null : inventionNameRejection(name),
+				description === undefined ? null : inventionDescriptionRejection(description),
+				longDescription === undefined ? null : inventionLongDescriptionRejection(longDescription),
+			]) {
+				if (rejection !== null) return c.json(inventionSaveV9Failure(rejection))
+			}
+
+			const updated = await updateInvention(c.env.DB, gate.invention.InventionId, {
+				generalPermission: permission,
+				allowTrial: typeof body.AllowTrial === 'boolean' ? body.AllowTrial : undefined,
+				name,
+				description,
+				longDescription,
+				imageName: edited('ImageName'),
+			})
+			if (updated === null) return c.json(inventionSaveV9Failure('No such invention'))
+			// The tags are reported as the ones the invention HAS, not as ones this call
+			// changed — it changes none. Same reading `v2/metadata` gives a null TagsRequest.
+			return c.json(toSaveResultV9(updated, updated.Tags ?? [], INVENTION_TAG_RESULT.success))
+		}
+	)
+
 	// Publish an invention, as the newer client sends it: a PascalCase body instead of a
 	// query string, and an Accessibility of its own — where `v3/publish` only ever flipped
 	// the published flag, this decides whether the result can be FOUND. Same enveloped
diff --git a/apps/api/src/test/integration/api.test.ts b/apps/api/src/test/integration/api.test.ts
index b2d4f7f..20f8a07 100644
--- a/apps/api/src/test/integration/api.test.ts
+++ b/apps/api/src/test/integration/api.test.ts
@@ -2185,6 +2185,158 @@ describe('public endpoints', () => {
 		expect(((await one.json()) as SavedInvention).Name).toBe('Clear Me')
 	})
 
+	// The permission picker's own call. `Permission` is the `GeneralPermission` ladder
+	// number — 40 is EditAndSave — and it decides what OTHER players may do with the
+	// invention, up to editing, re-publishing and charging for it.
+	test('POST /api/inventions/v2/update sets the permission from the body', async () => {
+		const save = await exports.default.fetch(`${ORIGIN}/api/inventions/v9/save`, {
+			method: 'POST',
+			headers: { ...(await bearer('5170')), 'Content-Type': 'application/json' },
+			body: JSON.stringify({ name: 'Permission Me', inventionDataFilename: 'perm.inv' }),
+		})
+		const inventionId = ((await save.json()) as InventionSaveV9Result).Value?.Invention.InventionId
+		expect(inventionId).toBeGreaterThan(0)
+
+		// The body verbatim as the client posts it.
+		const res = await exports.default.fetch(`${ORIGIN}/api/inventions/v2/update`, {
+			method: 'POST',
+			headers: { ...(await bearer('5170')), 'Content-Type': 'application/json' },
+			body: JSON.stringify({ InventionId: inventionId, Permission: 40 }),
+		})
+		expect(res.status).toBe(200)
+		const result = (await res.json()) as InventionSaveV9Result
+		expect(result.Success).toBe(true)
+		// The UPDATED invention comes back in the envelope: the client re-renders the detail
+		// sheet from `Value.Invention`, so a reply that omitted it would leave the old
+		// permission on screen.
+		expect(result.Value?.Invention.GeneralPermission).toBe(40)
+
+		// And it stuck.
+		const one = await exports.default.fetch(
+			`${ORIGIN}/api/inventions/v1?inventionId=${inventionId}`
+		)
+		expect(((await one.json()) as SavedInvention).GeneralPermission).toBe(40)
+	})
+
+	// THE gate. `GeneralPermission` is what lets another player edit, re-publish or charge
+	// for someone's build, so a write that took the caller's word for the id would let
+	// anyone hand themselves rights over any invention in the game. Refused in-band, the
+	// way `v2/metadata` refuses — this client cannot parse a bare error body — and, the
+	// part that matters, the stored permission must not move.
+	test('POST /api/inventions/v2/update is gated to the invention’s creator', async () => {
+		const save = await exports.default.fetch(`${ORIGIN}/api/inventions/v9/save`, {
+			method: 'POST',
+			headers: { ...(await bearer('5171')), 'Content-Type': 'application/json' },
+			body: JSON.stringify({ name: 'Not Yours Either', inventionDataFilename: 'nye.inv' }),
+		})
+		const inventionId = ((await save.json()) as InventionSaveV9Result).Value?.Invention.InventionId
+		const permissionNow = async () => {
+			const one = await exports.default.fetch(
+				`${ORIGIN}/api/inventions/v1?inventionId=${inventionId}`
+			)
+			return ((await one.json()) as SavedInvention).GeneralPermission
+		}
+		const before = await permissionNow()
+
+		// Another player, granting themselves Unlimited (100) over someone else's build.
+		const theirs = await exports.default.fetch(`${ORIGIN}/api/inventions/v2/update`, {
+			method: 'POST',
+			headers: { ...(await bearer('5172')), 'Content-Type': 'application/json' },
+			body: JSON.stringify({ InventionId: inventionId, Permission: 100 }),
+		})
+		expect(theirs.status).toBe(200)
+		expect(await theirs.json()).toEqual({
+			Value: null,
+			Success: false,
+			Error: 'Not your invention',
+			error_id: null,
+		})
+		expect(await permissionNow()).toBe(before)
+
+		// An unknown invention is the same kind of answer.
+		const missing = await exports.default.fetch(`${ORIGIN}/api/inventions/v2/update`, {
+			method: 'POST',
+			headers: { ...(await bearer('5171')), 'Content-Type': 'application/json' },
+			body: JSON.stringify({ InventionId: 987655, Permission: 40 }),
+		})
+		expect(missing.status).toBe(200)
+		expect((await missing.json()) as InventionSaveV9Result).toMatchObject({
+			Value: null,
+			Error: 'No such invention',
+		})
+
+		// A missing token is the one refusal that stays a transport failure — but it still
+		// answers the envelope, because an unparseable body crashes the client.
+		const anon = await exports.default.fetch(`${ORIGIN}/api/inventions/v2/update`, {
+			method: 'POST',
+			headers: { 'Content-Type': 'application/json' },
+			body: JSON.stringify({ InventionId: inventionId, Permission: 100 }),
+		})
+		expect(anon.status).toBe(401)
+		expect((await anon.json()) as InventionSaveV9Result).toMatchObject({
+			Value: null,
+			Success: false,
+		})
+		expect(await permissionNow()).toBe(before)
+	})
+
+	// A patch, not a replace — and specifically NOT `v4/publish`'s reading of a null
+	// permission, which is UseOnly. Publishing something without naming a permission is a
+	// decision; editing it without naming one is not, and defaulting here would silently
+	// demote an invention every time the creator renamed it.
+	test('POST /api/inventions/v2/update leaves a null permission alone', async () => {
+		const save = await exports.default.fetch(`${ORIGIN}/api/inventions/v9/save`, {
+			method: 'POST',
+			headers: { ...(await bearer('5173')), 'Content-Type': 'application/json' },
+			body: JSON.stringify({ name: 'Keep My Rights', inventionDataFilename: 'keep.inv' }),
+		})
+		const inventionId = ((await save.json()) as InventionSaveV9Result).Value?.Invention.InventionId
+
+		// Set it to Publish (60) first, so a fallback to UseOnly (20) would be visible.
+		await exports.default.fetch(`${ORIGIN}/api/inventions/v2/update`, {
+			method: 'POST',
+			headers: { ...(await bearer('5173')), 'Content-Type': 'application/json' },
+			body: JSON.stringify({ InventionId: inventionId, Permission: 60 }),
+		})
+
+		const res = await exports.default.fetch(`${ORIGIN}/api/inventions/v2/update`, {
+			method: 'POST',
+			headers: { ...(await bearer('5173')), 'Content-Type': 'application/json' },
+			body: JSON.stringify({ InventionId: inventionId, Permission: null, Name: 'Renamed' }),
+		})
+		expect(res.status).toBe(200)
+		const value = ((await res.json()) as InventionSaveV9Result).Value
+		expect(value?.Invention.GeneralPermission).toBe(60)
+		expect(value?.Invention.Name).toBe('Renamed')
+	})
+
+	// The same parser `v1/update`'s query param goes through, so a build that sends the
+	// ladder by NAME lands on the same level as one sending the number.
+	test('POST /api/inventions/v2/update accepts a permission named as a string', async () => {
+		const save = await exports.default.fetch(`${ORIGIN}/api/inventions/v9/save`, {
+			method: 'POST',
+			headers: { ...(await bearer('5174')), 'Content-Type': 'application/json' },
+			body: JSON.stringify({ name: 'Named Ladder', inventionDataFilename: 'named.inv' }),
+		})
+		const inventionId = ((await save.json()) as InventionSaveV9Result).Value?.Invention.InventionId
+
+		for (const [sent, expected] of [
+			['EditAndSave', 40],
+			['edit_and_save', 40],
+			['60', 60],
+		] as const) {
+			const res = await exports.default.fetch(`${ORIGIN}/api/inventions/v2/update`, {
+				method: 'POST',
+				headers: { ...(await bearer('5174')), 'Content-Type': 'application/json' },
+				body: JSON.stringify({ InventionId: inventionId, Permission: sent }),
+			})
+			expect(res.status).toBe(200)
+			expect(((await res.json()) as InventionSaveV9Result).Value?.Invention.GeneralPermission).toBe(
+				expected
+			)
+		}
+	})
+
 	test('PUT /api/inventions/v2/metadata refuses another creator’s invention in-band', async () => {
 		const save = await exports.default.fetch(`${ORIGIN}/api/inventions/v9/save`, {
 			method: 'POST',
@@ -8131,6 +8283,7 @@ describe('openapi', () => {
 			'POST /api/inventions/v1/update',
 			'POST /api/inventions/v1/updateprice',
 			'POST /api/inventions/v2/delete',
+			'POST /api/inventions/v2/update',
 			'POST /api/inventions/v4/publish',
 			'POST /api/inventions/v6/save',
 			'POST /api/inventions/v9/save',