diff --git a/README.md b/README.md
index 8d60b4c..4cd4bc4 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # Vector
 
-Hardware parts inventory system. Tracks serialized parts across sites → rooms → bins, with a full audit trail, repair/RMA workflow, tag-based organization, manufacturer EOL tracking, and signed webhook delivery for external integrations.
+Hardware parts inventory system. Tracks serialized parts across sites → rooms → bins and hosts (with externally-driven state/stack lifecycle), with a full audit trail, repair/RMA workflow, per-tech custody for broken-part holds and pre-staged spares, tag-based organization, category-per-model taxonomy, manufacturer EOL tracking, and signed webhook delivery for external integrations.
 
 Vector 2.0 is a ground-up TypeScript rewrite of the original JavaScript codebase, delivered as a pnpm + Turbo monorepo with shadcn/ui on the frontend and a service-layered Express API on the backend.
 
diff --git a/apps/api/src/controllers/custody.ts b/apps/api/src/controllers/custody.ts
index b13ecd9..a8c5cf1 100644
--- a/apps/api/src/controllers/custody.ts
+++ b/apps/api/src/controllers/custody.ts
@@ -31,3 +31,19 @@ export async function dropOff(
     next(err);
   }
 }
+
+export async function takeForRepair(
+  req: Request<{ partId: string }>,
+  res: Response,
+  next: NextFunction,
+) {
+  try {
+    if (!req.user) throw errors.unauthorized();
+    const part = await prisma.$transaction((tx) =>
+      svc.takeForRepair(tx, req.params.partId, req.user!),
+    );
+    res.json(part);
+  } catch (err) {
+    next(err);
+  }
+}
diff --git a/apps/api/src/routes/custody.ts b/apps/api/src/routes/custody.ts
index 6ff68b4..4ac81bf 100644
--- a/apps/api/src/routes/custody.ts
+++ b/apps/api/src/routes/custody.ts
@@ -13,5 +13,6 @@ router.post(
   validate('body', DropOffRequest),
   ctrl.dropOff,
 );
+router.post('/:partId/take-for-repair', requireAuth, ctrl.takeForRepair);
 
 export default router;
diff --git a/apps/api/src/services/custody.test.ts b/apps/api/src/services/custody.test.ts
index f0b2c35..4e83387 100644
--- a/apps/api/src/services/custody.test.ts
+++ b/apps/api/src/services/custody.test.ts
@@ -1,6 +1,6 @@
 import { describe, expect, it, vi } from 'vitest';
 import type { Tx, Actor } from './types.js';
-import { dropOff } from './custody.js';
+import { dropOff, takeForRepair } from './custody.js';
 
 const custodian: Actor = { id: 'user-1', username: 'tech', role: 'TECHNICIAN' };
 const admin: Actor = { id: 'user-admin', username: 'boss', role: 'ADMIN' };
@@ -166,4 +166,60 @@ describe('custody.dropOff', () => {
       dropOff(tx, 'p-missing', { binId: null }, custodian),
     ).rejects.toMatchObject({ status: 404 });
   });
+
+  it('PENDING_REPAIR → SPARE when returned with a bin; custodian cleared', async () => {
+    const { tx, current } = buildTx(
+      custodyPart({ state: 'PENDING_REPAIR', binId: null }),
+    );
+
+    await dropOff(tx, 'p-1', { binId: 'bin-7' }, custodian);
+
+    expect(current.state).toBe('SPARE');
+    expect(current.binId).toBe('bin-7');
+    expect(current.custodianId).toBeNull();
+  });
+
+  it('rejects PENDING_REPAIR drop-off without a bin with 400', async () => {
+    const { tx, partUpdate } = buildTx(
+      custodyPart({ state: 'PENDING_REPAIR', binId: null }),
+    );
+
+    await expect(
+      dropOff(tx, 'p-1', { binId: null }, custodian),
+    ).rejects.toMatchObject({ status: 400 });
+    expect(partUpdate).not.toHaveBeenCalled();
+  });
+});
+
+describe('custody.takeForRepair', () => {
+  it('SPARE → PENDING_REPAIR with the actor as custodian', async () => {
+    const { tx, current } = buildTx(
+      custodyPart({ state: 'SPARE', custodianId: null, custodian: null, binId: 'bin-1' }),
+    );
+
+    await takeForRepair(tx, 'p-1', custodian);
+
+    expect(current.state).toBe('PENDING_REPAIR');
+    expect(current.custodianId).toBe('user-1');
+  });
+
+  it('rejects take-for-repair on a non-SPARE part with 400', async () => {
+    const { tx, partUpdate } = buildTx(custodyPart({ state: 'DEPLOYED' }));
+
+    await expect(takeForRepair(tx, 'p-1', custodian)).rejects.toMatchObject({
+      status: 400,
+    });
+    expect(partUpdate).not.toHaveBeenCalled();
+  });
+
+  it('rejects take-for-repair on a missing part with 404', async () => {
+    const tx = {
+      part: { findUnique: async () => null, update: vi.fn() },
+      partEvent: { createMany: vi.fn() },
+    } as unknown as Tx;
+
+    await expect(takeForRepair(tx, 'p-missing', custodian)).rejects.toMatchObject({
+      status: 404,
+    });
+  });
 });
diff --git a/apps/api/src/services/custody.ts b/apps/api/src/services/custody.ts
index e419e00..8cbe1ec 100644
--- a/apps/api/src/services/custody.ts
+++ b/apps/api/src/services/custody.ts
@@ -27,6 +27,16 @@ export async function listMine(tx: Tx, userId: string, q: CustodyListQuery) {
   return { data, page, pageSize, total };
 }
 
+// Map of custody-state → state the part returns to when dropped off.
+// PENDING_REPAIR is a spare the tech picked up for a future swap; on return it goes back to
+// SPARE and must land in a bin (no useful "in-limbo" state for spares). The broken-part
+// paths continue to allow binId=null since techs sometimes hold broken parts without a bin.
+const DROP_OFF_TARGET: Record<string, { next: 'BROKEN' | 'PENDING_DESTRUCTION' | 'SPARE'; binRequired: boolean }> = {
+  PENDING_DROP_IN_CUSTODY: { next: 'BROKEN', binRequired: false },
+  PENDING_DESTRUCTION_IN_CUSTODY: { next: 'PENDING_DESTRUCTION', binRequired: false },
+  PENDING_REPAIR: { next: 'SPARE', binRequired: true },
+};
+
 export async function dropOff(
   tx: Tx,
   partId: string,
@@ -36,23 +46,35 @@ export async function dropOff(
   const part = await tx.part.findUnique({ where: { id: partId } });
   if (!part) throw errors.notFound('Part');
 
-  if (
-    part.state !== 'PENDING_DROP_IN_CUSTODY' &&
-    part.state !== 'PENDING_DESTRUCTION_IN_CUSTODY'
-  ) {
-    throw errors.badRequest('Part is not in custody');
-  }
+  const target = DROP_OFF_TARGET[part.state];
+  if (!target) throw errors.badRequest('Part is not in custody');
   if (part.custodianId !== actor.id && actor.role !== 'ADMIN') {
     throw errors.forbidden('Only the current custodian can drop off this part');
   }
-
-  const nextState =
-    part.state === 'PENDING_DROP_IN_CUSTODY' ? 'BROKEN' : 'PENDING_DESTRUCTION';
+  if (target.binRequired && !input.binId) {
+    throw errors.badRequest('A bin is required when returning a spare to inventory');
+  }
 
   return partsSvc.update(
     tx,
     partId,
-    { state: nextState, binId: input.binId ?? null, custodianId: null },
+    { state: target.next, binId: input.binId ?? null, custodianId: null },
+    actor,
+  );
+}
+
+// A tech takes a SPARE into their custody for a future repair. The part waits in
+// PENDING_REPAIR until it's used in a Repair (→ DEPLOYED) or dropped back into a bin (→ SPARE).
+export async function takeForRepair(tx: Tx, partId: string, actor: Actor) {
+  const part = await tx.part.findUnique({ where: { id: partId } });
+  if (!part) throw errors.notFound('Part');
+  if (part.state !== 'SPARE') {
+    throw errors.badRequest('Only SPARE parts can be taken for a repair');
+  }
+  return partsSvc.update(
+    tx,
+    partId,
+    { state: 'PENDING_REPAIR', custodianId: actor.id },
     actor,
   );
 }
diff --git a/apps/api/src/services/hosts.test.ts b/apps/api/src/services/hosts.test.ts
new file mode 100644
index 0000000..94fb7ee
--- /dev/null
+++ b/apps/api/src/services/hosts.test.ts
@@ -0,0 +1,117 @@
+import { describe, expect, it, vi } from 'vitest';
+import type { Tx } from './types.js';
+import { create, update } from './hosts.js';
+
+interface HostRow {
+  id: string;
+  assetId: string;
+  name: string;
+  location: string | null;
+  notes: string | null;
+  state: string;
+  stack: string;
+}
+
+function buildTx(seed: HostRow[] = []) {
+  const registry = new Map(seed.map((h) => [h.id, h]));
+
+  const tx = {
+    host: {
+      create: vi.fn(async (args: { data: Record<string, unknown> }) => {
+        const row: HostRow = {
+          id: `host-${registry.size + 1}`,
+          assetId: String(args.data.assetId),
+          name: String(args.data.name),
+          location: (args.data.location as string | null) ?? null,
+          notes: (args.data.notes as string | null) ?? null,
+          state: String(args.data.state ?? 'DEPLOYED'),
+          stack: String(args.data.stack ?? 'PRODUCTION'),
+        };
+        registry.set(row.id, row);
+        return row;
+      }),
+      update: vi.fn(async (args: { where: { id: string }; data: Record<string, unknown> }) => {
+        const current = registry.get(args.where.id);
+        if (!current) throw new Error(`No host ${args.where.id}`);
+        const d = args.data;
+        if (d.assetId !== undefined) current.assetId = String(d.assetId);
+        if (d.name !== undefined) current.name = String(d.name);
+        if (d.location !== undefined) current.location = (d.location as string | null) ?? null;
+        if (d.notes !== undefined) current.notes = (d.notes as string | null) ?? null;
+        if (d.state !== undefined) current.state = String(d.state);
+        if (d.stack !== undefined) current.stack = String(d.stack);
+        return current;
+      }),
+    },
+  } as unknown as Tx;
+
+  return { tx, registry };
+}
+
+describe('hosts.create', () => {
+  it('defaults state=DEPLOYED and stack=PRODUCTION when not supplied', async () => {
+    const { tx } = buildTx();
+
+    const host = await create(tx, { assetId: 'A-1', name: 'rack-1' });
+
+    expect(host.state).toBe('DEPLOYED');
+    expect(host.stack).toBe('PRODUCTION');
+  });
+
+  it('persists explicit state and stack', async () => {
+    const { tx } = buildTx();
+
+    const host = await create(tx, {
+      assetId: 'A-2',
+      name: 'rack-2',
+      state: 'TESTING',
+      stack: 'VETTING',
+    });
+
+    expect(host.state).toBe('TESTING');
+    expect(host.stack).toBe('VETTING');
+  });
+});
+
+describe('hosts.update', () => {
+  it('updates state and stack when provided', async () => {
+    const { tx, registry } = buildTx([
+      {
+        id: 'host-1',
+        assetId: 'A-1',
+        name: 'rack-1',
+        location: null,
+        notes: null,
+        state: 'DEPLOYED',
+        stack: 'PRODUCTION',
+      },
+    ]);
+
+    await update(tx, 'host-1', { state: 'DEGRADED', stack: 'VETTING' });
+
+    const row = registry.get('host-1')!;
+    expect(row.state).toBe('DEGRADED');
+    expect(row.stack).toBe('VETTING');
+  });
+
+  it('leaves state/stack untouched when not provided', async () => {
+    const { tx, registry } = buildTx([
+      {
+        id: 'host-1',
+        assetId: 'A-1',
+        name: 'rack-1',
+        location: null,
+        notes: null,
+        state: 'TESTING',
+        stack: 'VETTING',
+      },
+    ]);
+
+    await update(tx, 'host-1', { name: 'rack-1-renamed' });
+
+    const row = registry.get('host-1')!;
+    expect(row.state).toBe('TESTING');
+    expect(row.stack).toBe('VETTING');
+    expect(row.name).toBe('rack-1-renamed');
+  });
+});
diff --git a/apps/api/src/services/hosts.ts b/apps/api/src/services/hosts.ts
index cb6ebde..f34b094 100644
--- a/apps/api/src/services/hosts.ts
+++ b/apps/api/src/services/hosts.ts
@@ -14,15 +14,16 @@ function mapUniqueViolation(target: unknown): string {
 
 export async function list(tx: Tx, q: HostListQuery) {
   const { page, pageSize, q: search } = q;
-  const where: Prisma.HostWhereInput = search
-    ? {
-        OR: [
-          { name: { contains: search } },
-          { assetId: { contains: search } },
-          { location: { contains: search } },
-        ],
-      }
-    : {};
+  const where: Prisma.HostWhereInput = {};
+  if (search) {
+    where.OR = [
+      { name: { contains: search } },
+      { assetId: { contains: search } },
+      { location: { contains: search } },
+    ];
+  }
+  if (q.state) where.state = q.state;
+  if (q.stack) where.stack = q.stack;
   const [data, total] = await Promise.all([
     tx.host.findMany({
       where,
@@ -55,6 +56,8 @@ export async function create(tx: Tx, input: CreateHostRequest) {
         name: input.name,
         location: input.location ?? null,
         notes: input.notes ?? null,
+        state: input.state ?? 'DEPLOYED',
+        stack: input.stack ?? 'PRODUCTION',
       },
     });
   } catch (err) {
@@ -71,6 +74,8 @@ export async function update(tx: Tx, id: string, input: UpdateHostRequest) {
   if (input.name !== undefined) data.name = input.name;
   if (input.location !== undefined) data.location = input.location;
   if (input.notes !== undefined) data.notes = input.notes;
+  if (input.state !== undefined) data.state = input.state;
+  if (input.stack !== undefined) data.stack = input.stack;
   try {
     return await tx.host.update({ where: { id }, data });
   } catch (err) {
diff --git a/apps/api/src/services/part-models.ts b/apps/api/src/services/part-models.ts
index 48619aa..52a08fa 100644
--- a/apps/api/src/services/part-models.ts
+++ b/apps/api/src/services/part-models.ts
@@ -9,13 +9,15 @@ import type { Tx } from './types.js';
 
 const partModelInclude = {
   manufacturer: true,
+  category: true,
   _count: { select: { parts: true } },
 } satisfies Prisma.PartModelInclude;
 
 export async function list(tx: Tx, q: PartModelListQuery) {
-  const { page, pageSize, manufacturerId, q: search, eolBefore } = q;
+  const { page, pageSize, manufacturerId, categoryId, q: search, eolBefore } = q;
   const where: Prisma.PartModelWhereInput = {};
   if (manufacturerId) where.manufacturerId = manufacturerId;
+  if (categoryId) where.categoryId = categoryId;
   if (search) where.mpn = { contains: search };
   if (eolBefore) where.eolDate = { lte: new Date(eolBefore) };
 
@@ -42,6 +44,7 @@ export async function create(tx: Tx, input: CreatePartModelRequest) {
       data: {
         manufacturerId: input.manufacturerId,
         mpn: input.mpn,
+        categoryId: input.categoryId ?? null,
         eolDate: input.eolDate ? new Date(input.eolDate) : null,
         destroyOnFail: input.destroyOnFail ?? false,
         notes: input.notes ?? null,
@@ -51,7 +54,7 @@ export async function create(tx: Tx, input: CreatePartModelRequest) {
   } catch (err) {
     if (err instanceof Prisma.PrismaClientKnownRequestError) {
       if (err.code === 'P2002') throw errors.conflict('MPN already exists for this manufacturer');
-      if (err.code === 'P2003') throw errors.badRequest('Manufacturer does not exist');
+      if (err.code === 'P2003') throw errors.badRequest('Manufacturer or category does not exist');
     }
     throw err;
   }
@@ -63,6 +66,11 @@ export async function update(tx: Tx, id: string, input: UpdatePartModelRequest)
     data.manufacturer = { connect: { id: input.manufacturerId } };
   }
   if (input.mpn !== undefined) data.mpn = input.mpn;
+  if (input.categoryId !== undefined) {
+    data.category = input.categoryId
+      ? { connect: { id: input.categoryId } }
+      : { disconnect: true };
+  }
   if (input.eolDate !== undefined) {
     data.eolDate = input.eolDate ? new Date(input.eolDate) : null;
   }
@@ -74,6 +82,7 @@ export async function update(tx: Tx, id: string, input: UpdatePartModelRequest)
     if (err instanceof Prisma.PrismaClientKnownRequestError) {
       if (err.code === 'P2025') throw errors.notFound('Part model');
       if (err.code === 'P2002') throw errors.conflict('MPN already exists for this manufacturer');
+      if (err.code === 'P2003') throw errors.badRequest('Manufacturer or category does not exist');
     }
     throw err;
   }
diff --git a/apps/api/src/services/parts.ts b/apps/api/src/services/parts.ts
index 8700c9c..28a102f 100644
--- a/apps/api/src/services/parts.ts
+++ b/apps/api/src/services/parts.ts
@@ -15,7 +15,7 @@ import type { Actor, Tx } from './types.js';
 // The matrix is:
 //   DEPLOYED                          — hostId required, binId forbidden, custodianId forbidden
 //   SPARE / BROKEN / PENDING_DESTRUCTION — binId optional, hostId + custodian forbidden
-//   PENDING_DROP_IN_CUSTODY / PENDING_DESTRUCTION_IN_CUSTODY
+//   PENDING_DROP_IN_CUSTODY / PENDING_DESTRUCTION_IN_CUSTODY / PENDING_REPAIR
 //                                     — custodianId required, host + bin forbidden
 // Callers only need to pass what's changing; anything omitted is inherited from `current`.
 function resolveLocation(
@@ -43,7 +43,11 @@ function resolveLocation(
     return { binId: null, hostId, custodianId: null };
   }
 
-  if (state === 'PENDING_DROP_IN_CUSTODY' || state === 'PENDING_DESTRUCTION_IN_CUSTODY') {
+  if (
+    state === 'PENDING_DROP_IN_CUSTODY' ||
+    state === 'PENDING_DESTRUCTION_IN_CUSTODY' ||
+    state === 'PENDING_REPAIR'
+  ) {
     const custodianId =
       input.custodianId !== undefined ? input.custodianId : current.custodianId;
     if (!custodianId) throw errors.badRequest('A part in custody must name a custodian');
@@ -65,9 +69,8 @@ function resolveLocation(
 
 const partInclude = {
   manufacturer: true,
-  partModel: true,
+  partModel: { include: { category: true } },
   bin: { include: { room: { include: { site: true } } } },
-  category: true,
   host: true,
   custodian: { select: { id: true, username: true } },
   tags: { include: { tag: true } },
@@ -127,7 +130,6 @@ function buildWhere(q: PartListQuery): Prisma.PartWhereInput {
   if (q.custodianId) where.custodianId = q.custodianId;
   if (q.manufacturerId) where.manufacturerId = q.manufacturerId;
   if (q.partModelId) where.partModelId = q.partModelId;
-  if (q.categoryId) where.categoryId = q.categoryId;
   if (q.serialNumber) where.serialNumber = { contains: q.serialNumber };
   if (q.q) {
     where.OR = [
@@ -141,6 +143,7 @@ function buildWhere(q: PartListQuery): Prisma.PartWhereInput {
   const partModelFilter: Prisma.PartModelWhereInput = {};
   if (q.mpn) partModelFilter.mpn = { contains: q.mpn };
   if (q.eolOnly) partModelFilter.eolDate = { lt: new Date() };
+  if (q.categoryId) partModelFilter.categoryId = q.categoryId;
   if (Object.keys(partModelFilter).length > 0) where.partModel = partModelFilter;
 
   return where;
@@ -196,7 +199,6 @@ export async function create(
         binId: location.binId,
         hostId: location.hostId,
         custodianId: location.custodianId,
-        categoryId: input.categoryId ?? null,
         notes: input.notes ?? null,
       },
       include: partInclude,
@@ -276,11 +278,6 @@ export async function update(
       : { disconnect: true };
   }
 
-  if (input.categoryId !== undefined) {
-    data.category = input.categoryId
-      ? { connect: { id: input.categoryId } }
-      : { disconnect: true };
-  }
   if (input.notes !== undefined) data.notes = input.notes;
 
   let part: PartWithRelations;
@@ -357,16 +354,6 @@ export async function update(
       newValue: input.serialNumber,
     });
   }
-  if (input.categoryId !== undefined && input.categoryId !== current.categoryId) {
-    events.push({
-      partId: part.id,
-      userId,
-      type: 'FIELD_UPDATED',
-      field: 'category',
-      oldValue: current.category?.name ?? null,
-      newValue: part.category?.name ?? null,
-    });
-  }
   if (input.price !== undefined && input.price !== current.price) {
     events.push({
       partId: part.id,
diff --git a/apps/api/src/services/repairs.test.ts b/apps/api/src/services/repairs.test.ts
index 0d805c6..f02575e 100644
--- a/apps/api/src/services/repairs.test.ts
+++ b/apps/api/src/services/repairs.test.ts
@@ -514,6 +514,82 @@ describe('repairs.log — validation failures', () => {
     expect(events).toEqual(['repair.logged']);
   });
 
+  it('accepts a PENDING_REPAIR replacement held by the actor', async () => {
+    const broken = partRow({
+      id: 'p-broken',
+      serialNumber: 'SN-BROKEN',
+      partModelId: brokenModel.id,
+      state: 'DEPLOYED',
+      hostId: 'host-1',
+      host: host1,
+      partModel: brokenModel,
+    });
+    const replacement = partRow({
+      id: 'p-replacement',
+      serialNumber: 'SN-REPLACE',
+      partModelId: replacementModel.id,
+      state: 'PENDING_REPAIR',
+      custodianId: actor.id,
+      custodian: { id: actor.id, username: actor.username },
+      partModel: replacementModel,
+    });
+    const { tx, registry } = buildTx({ parts: [broken, replacement], hosts: [host1] });
+
+    const r = await log(
+      tx,
+      {
+        hostId: 'host-1',
+        brokenSerial: 'SN-BROKEN',
+        brokenMpn: 'WD-BROKEN',
+        brokenManufacturerId: 'mfr-1',
+        replacementSerial: 'SN-REPLACE',
+      },
+      actor,
+    );
+
+    expect(r.id).toBe('repair-1');
+    const updatedReplacement = registry.get('p-replacement')!;
+    expect(updatedReplacement.state).toBe('DEPLOYED');
+    expect(updatedReplacement.hostId).toBe('host-1');
+    expect(updatedReplacement.custodianId).toBeNull();
+  });
+
+  it('rejects a PENDING_REPAIR replacement held by someone else with 400', async () => {
+    const broken = partRow({
+      id: 'p-broken',
+      serialNumber: 'SN-BROKEN',
+      partModelId: brokenModel.id,
+      state: 'DEPLOYED',
+      hostId: 'host-1',
+      host: host1,
+      partModel: brokenModel,
+    });
+    const replacement = partRow({
+      id: 'p-replacement',
+      serialNumber: 'SN-REPLACE',
+      partModelId: replacementModel.id,
+      state: 'PENDING_REPAIR',
+      custodianId: 'user-other',
+      custodian: { id: 'user-other', username: 'someone' },
+      partModel: replacementModel,
+    });
+    const { tx } = buildTx({ parts: [broken, replacement], hosts: [host1] });
+
+    await expect(
+      log(
+        tx,
+        {
+          hostId: 'host-1',
+          brokenSerial: 'SN-BROKEN',
+          brokenMpn: 'WD-BROKEN',
+          brokenManufacturerId: 'mfr-1',
+          replacementSerial: 'SN-REPLACE',
+        },
+        actor,
+      ),
+    ).rejects.toMatchObject({ status: 400 });
+  });
+
   it('rejects when broken part is on a different host than the repair', async () => {
     const broken = partRow({
       id: 'p-broken',
diff --git a/apps/api/src/services/repairs.ts b/apps/api/src/services/repairs.ts
index d21db67..93f2e78 100644
--- a/apps/api/src/services/repairs.ts
+++ b/apps/api/src/services/repairs.ts
@@ -78,7 +78,7 @@ export async function log(
 ): Promise<RepairWithRelations> {
   const host = await resolveHost(tx, input);
 
-  // 1. Resolve replacement — must exist, must be SPARE.
+  // 1. Resolve replacement — must exist; must be SPARE, or a PENDING_REPAIR held by the actor.
   const replacement = await tx.part.findUnique({
     where: { serialNumber: input.replacementSerial },
     include: { partModel: true },
@@ -86,9 +86,11 @@ export async function log(
   if (!replacement) {
     throw errors.badRequest(`Replacement part ${input.replacementSerial} not found`);
   }
-  if (replacement.state !== 'SPARE') {
+  const heldForRepairByActor =
+    replacement.state === 'PENDING_REPAIR' && replacement.custodianId === actor.id;
+  if (replacement.state !== 'SPARE' && !heldForRepairByActor) {
     throw errors.badRequest(
-      `Replacement part ${input.replacementSerial} is ${replacement.state}, must be SPARE`,
+      `Replacement part ${input.replacementSerial} is ${replacement.state}, must be SPARE or PENDING_REPAIR held by you`,
     );
   }
 
@@ -104,10 +106,22 @@ export async function log(
       );
     }
   } else {
-    const pm = await partModelsSvc.upsertByMpn(tx, {
-      manufacturerId: input.brokenManufacturerId,
-      mpn: input.brokenMpn,
-    });
+    let pm: { id: string; manufacturerId: string };
+    if (input.brokenPartModelId) {
+      const existing = await tx.partModel.findUnique({ where: { id: input.brokenPartModelId } });
+      if (!existing) throw errors.badRequest('Broken part model does not exist');
+      pm = { id: existing.id, manufacturerId: existing.manufacturerId };
+    } else {
+      if (!input.brokenMpn || !input.brokenManufacturerId) {
+        throw errors.badRequest(
+          'Provide brokenPartModelId or both brokenMpn and brokenManufacturerId',
+        );
+      }
+      pm = await partModelsSvc.upsertByMpn(tx, {
+        manufacturerId: input.brokenManufacturerId,
+        mpn: input.brokenMpn,
+      });
+    }
     const created = await tx.part.create({
       data: {
         serialNumber: input.brokenSerial,
diff --git a/apps/web/src/components/common/PartModelCombobox.tsx b/apps/web/src/components/common/PartModelCombobox.tsx
new file mode 100644
index 0000000..2f88136
--- /dev/null
+++ b/apps/web/src/components/common/PartModelCombobox.tsx
@@ -0,0 +1,169 @@
+import { useEffect, useMemo, useRef, useState } from 'react';
+import { useQuery } from '@tanstack/react-query';
+import { Check, ChevronsUpDown, Plus, X } from 'lucide-react';
+import {
+  Button,
+  Command,
+  CommandEmpty,
+  CommandGroup,
+  CommandInput,
+  CommandItem,
+  CommandList,
+  Popover,
+  PopoverContent,
+  PopoverTrigger,
+  cn,
+} from '@vector/ui';
+import { listPartModels } from '../../lib/api/part-models.js';
+import { queryKeys } from '../../lib/queryKeys.js';
+import type { PartModel } from '../../lib/api/types.js';
+
+// Async combobox over the PartModel catalog. Two outputs:
+//   - onPick(model): user chose an existing PartModel — the form should hide the manufacturer
+//     field and send { partModelId } at submit time.
+//   - onCreateNew(mpn): user typed an MPN not in the catalog and picked the "Create new" row —
+//     the form should reveal the manufacturer picker and send { mpn, manufacturerId } at submit
+//     time so partModels.upsertByMpn provisions the row.
+interface PartModelComboboxProps {
+  value: PartModel | null;
+  newMpn: string | null;
+  onPick: (model: PartModel) => void;
+  onCreateNew: (mpn: string) => void;
+  onClear: () => void;
+  disabled?: boolean;
+  placeholder?: string;
+}
+
+export function PartModelCombobox({
+  value,
+  newMpn,
+  onPick,
+  onCreateNew,
+  onClear,
+  disabled,
+  placeholder = 'Search MPN…',
+}: PartModelComboboxProps) {
+  const [open, setOpen] = useState(false);
+  const [search, setSearch] = useState('');
+  const [debounced, setDebounced] = useState('');
+
+  useEffect(() => {
+    const t = setTimeout(() => setDebounced(search.trim()), 200);
+    return () => clearTimeout(t);
+  }, [search]);
+
+  const query = useQuery({
+    queryKey: queryKeys.partModels.list({ q: debounced, pageSize: 20 }),
+    queryFn: () => listPartModels({ q: debounced || undefined, pageSize: 20 }),
+    enabled: open,
+  });
+
+  const results = useMemo(() => query.data?.data ?? [], [query.data]);
+
+  const typed = search.trim();
+  const hasExactMatch = results.some(
+    (m) => m.mpn.toLowerCase() === typed.toLowerCase(),
+  );
+  const canCreate = typed.length > 0 && !hasExactMatch;
+
+  const triggerRef = useRef<HTMLButtonElement>(null);
+
+  const label = value
+    ? `${value.manufacturer?.name ?? ''} — ${value.mpn}`
+    : newMpn
+      ? `New model: ${newMpn}`
+      : '';
+
+  return (
+    <div className="flex items-center gap-1">
+      <Popover open={open} onOpenChange={(o) => !disabled && setOpen(o)}>
+        <PopoverTrigger asChild>
+          <Button
+            ref={triggerRef}
+            type="button"
+            variant="outline"
+            role="combobox"
+            aria-expanded={open}
+            disabled={disabled}
+            className={cn(
+              'flex-1 justify-between font-normal',
+              !value && !newMpn && 'text-muted-foreground',
+            )}
+          >
+            <span className="truncate">{label || placeholder}</span>
+            <ChevronsUpDown className="h-4 w-4 shrink-0 opacity-50" />
+          </Button>
+        </PopoverTrigger>
+        <PopoverContent
+          className="p-0"
+          align="start"
+          style={{ width: triggerRef.current?.offsetWidth }}
+        >
+          <Command shouldFilter={false}>
+            <CommandInput
+              placeholder="Type MPN…"
+              value={search}
+              onValueChange={setSearch}
+            />
+            <CommandList>
+              <CommandEmpty>
+                {query.isLoading ? 'Searching…' : 'No models found.'}
+              </CommandEmpty>
+              <CommandGroup>
+                {results.map((m) => (
+                  <CommandItem
+                    key={m.id}
+                    value={m.id}
+                    onSelect={() => {
+                      onPick(m);
+                      setSearch('');
+                      setOpen(false);
+                    }}
+                  >
+                    <span className="flex-1 truncate">
+                      <span className="text-muted-foreground">
+                        {m.manufacturer?.name ?? '—'} —{' '}
+                      </span>
+                      <span className="font-mono">{m.mpn}</span>
+                    </span>
+                    <Check
+                      className={cn(
+                        'ml-auto h-4 w-4 opacity-0',
+                        value?.id === m.id && 'opacity-100',
+                      )}
+                    />
+                  </CommandItem>
+                ))}
+                {canCreate && (
+                  <CommandItem
+                    value={`__create__${typed}`}
+                    onSelect={() => {
+                      onCreateNew(typed);
+                      setSearch('');
+                      setOpen(false);
+                    }}
+                  >
+                    <Plus className="h-3.5 w-3.5" />
+                    Create new model: <span className="font-mono">{typed}</span>
+                  </CommandItem>
+                )}
+              </CommandGroup>
+            </CommandList>
+          </Command>
+        </PopoverContent>
+      </Popover>
+      {(value || newMpn) && !disabled && (
+        <Button
+          type="button"
+          variant="ghost"
+          size="icon"
+          className="h-9 w-9 shrink-0"
+          onClick={onClear}
+          aria-label="Clear selection"
+        >
+          <X className="h-4 w-4" />
+        </Button>
+      )}
+    </div>
+  );
+}
diff --git a/apps/web/src/components/custody/DropOffDialog.tsx b/apps/web/src/components/custody/DropOffDialog.tsx
index 70246f2..7b0a7bc 100644
--- a/apps/web/src/components/custody/DropOffDialog.tsx
+++ b/apps/web/src/components/custody/DropOffDialog.tsx
@@ -43,17 +43,23 @@ export function DropOffDialog({ part, onOpenChange, onConfirm, pending }: DropOf
   });
 
   const destruction = part?.state === 'PENDING_DESTRUCTION_IN_CUSTODY';
+  // Spares returned from custody must land in a bin — we don't have a useful "in limbo"
+  // SPARE state. Destruction / broken drop-offs still allow an unassigned bin.
+  const returningSpare = part?.state === 'PENDING_REPAIR';
+  const title = returningSpare ? 'Return spare to bin' : 'Drop in bin';
+  const description = returningSpare
+    ? `Return ${part?.serialNumber ?? ''} to inventory. Choose a bin — required when returning a spare.`
+    : destruction
+      ? 'This part is flagged for destruction. It will move to pending-destruction — optionally place it in a destruction bin.'
+      : `Dropping ${part?.serialNumber ?? ''} into a bin marks it broken.`;
+  const confirmDisabled = pending || (returningSpare && !binId);
 
   return (
     <Dialog open={open} onOpenChange={onOpenChange}>
       <DialogContent className="max-w-sm">
         <DialogHeader>
-          <DialogTitle>Drop in bin</DialogTitle>
-          <DialogDescription>
-            {destruction
-              ? 'This part is flagged for destruction. It will move to pending-destruction — optionally place it in a destruction bin.'
-              : `Dropping ${part?.serialNumber ?? ''} into a bin marks it broken.`}
-          </DialogDescription>
+          <DialogTitle>{title}</DialogTitle>
+          <DialogDescription>{description}</DialogDescription>
         </DialogHeader>
 
         <div className="space-y-2 text-sm">
@@ -62,10 +68,10 @@ export function DropOffDialog({ part, onOpenChange, onConfirm, pending }: DropOf
             onValueChange={(v) => setBinId(v === UNASSIGNED ? '' : v)}
           >
             <SelectTrigger>
-              <SelectValue placeholder="Unassigned" />
+              <SelectValue placeholder={returningSpare ? 'Select a bin' : 'Unassigned'} />
             </SelectTrigger>
             <SelectContent>
-              <SelectItem value={UNASSIGNED}>Unassigned</SelectItem>
+              {!returningSpare && <SelectItem value={UNASSIGNED}>Unassigned</SelectItem>}
               {bins.data?.data.map((b) => (
                 <SelectItem key={b.id} value={b.id}>
                   {b.fullPath ?? b.name}
@@ -84,9 +90,9 @@ export function DropOffDialog({ part, onOpenChange, onConfirm, pending }: DropOf
           >
             Cancel
           </Button>
-          <Button onClick={() => onConfirm(binId || null)} disabled={pending}>
+          <Button onClick={() => onConfirm(binId || null)} disabled={confirmDisabled}>
             {pending && <Loader2 className="h-4 w-4 animate-spin" />}
-            Drop off
+            {returningSpare ? 'Return' : 'Drop off'}
           </Button>
         </DialogFooter>
       </DialogContent>
diff --git a/apps/web/src/components/hosts/HostFormDialog.tsx b/apps/web/src/components/hosts/HostFormDialog.tsx
index 69155d8..1c201e7 100644
--- a/apps/web/src/components/hosts/HostFormDialog.tsx
+++ b/apps/web/src/components/hosts/HostFormDialog.tsx
@@ -5,6 +5,7 @@ import { useMutation, useQueryClient } from '@tanstack/react-query';
 import { z } from 'zod';
 import { Loader2 } from 'lucide-react';
 import { toast } from 'sonner';
+import { HostStack, HostState } from '@vector/shared';
 import {
   Button,
   Dialog,
@@ -20,6 +21,11 @@ import {
   FormLabel,
   FormMessage,
   Input,
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue,
   Textarea,
 } from '@vector/ui';
 import { createHost, updateHost } from '../../lib/api/hosts.js';
@@ -32,9 +38,22 @@ const Schema = z.object({
   name: z.string().min(1, 'Required').max(128),
   location: z.string().max(256).optional(),
   notes: z.string().max(4096).optional(),
+  state: HostState,
+  stack: HostStack,
 });
 type Values = z.infer<typeof Schema>;
 
+const STATE_LABELS: Record<z.infer<typeof HostState>, string> = {
+  DEPLOYED: 'Deployed',
+  DEGRADED: 'Degraded',
+  TESTING: 'Testing',
+};
+
+const STACK_LABELS: Record<z.infer<typeof HostStack>, string> = {
+  PRODUCTION: 'Production',
+  VETTING: 'Vetting',
+};
+
 interface HostFormDialogProps {
   open: boolean;
   onOpenChange: (open: boolean) => void;
@@ -47,7 +66,14 @@ export function HostFormDialog({ open, onOpenChange, host }: HostFormDialogProps
 
   const form = useForm<Values>({
     resolver: zodResolver(Schema),
-    defaultValues: { assetId: '', name: '', location: '', notes: '' },
+    defaultValues: {
+      assetId: '',
+      name: '',
+      location: '',
+      notes: '',
+      state: 'DEPLOYED',
+      stack: 'PRODUCTION',
+    },
   });
 
   useEffect(() => {
@@ -57,6 +83,8 @@ export function HostFormDialog({ open, onOpenChange, host }: HostFormDialogProps
       name: host?.name ?? '',
       location: host?.location ?? '',
       notes: host?.notes ?? '',
+      state: host?.state ?? 'DEPLOYED',
+      stack: host?.stack ?? 'PRODUCTION',
     });
   }, [open, host, form]);
 
@@ -68,6 +96,8 @@ export function HostFormDialog({ open, onOpenChange, host }: HostFormDialogProps
           name: values.name,
           location: values.location ? values.location : null,
           notes: values.notes ? values.notes : null,
+          state: values.state,
+          stack: values.stack,
         });
       }
       return createHost({
@@ -75,6 +105,8 @@ export function HostFormDialog({ open, onOpenChange, host }: HostFormDialogProps
         name: values.name,
         location: values.location ? values.location : null,
         notes: values.notes ? values.notes : null,
+        state: values.state,
+        stack: values.stack,
       });
     },
     onSuccess: () => {
@@ -137,6 +169,56 @@ export function HostFormDialog({ open, onOpenChange, host }: HostFormDialogProps
                 </FormItem>
               )}
             />
+            <div className="grid grid-cols-2 gap-3">
+              <FormField
+                control={form.control}
+                name="state"
+                render={({ field }) => (
+                  <FormItem>
+                    <FormLabel>State</FormLabel>
+                    <Select value={field.value} onValueChange={field.onChange}>
+                      <FormControl>
+                        <SelectTrigger>
+                          <SelectValue />
+                        </SelectTrigger>
+                      </FormControl>
+                      <SelectContent>
+                        {HostState.options.map((s) => (
+                          <SelectItem key={s} value={s}>
+                            {STATE_LABELS[s]}
+                          </SelectItem>
+                        ))}
+                      </SelectContent>
+                    </Select>
+                    <FormMessage />
+                  </FormItem>
+                )}
+              />
+              <FormField
+                control={form.control}
+                name="stack"
+                render={({ field }) => (
+                  <FormItem>
+                    <FormLabel>Stack</FormLabel>
+                    <Select value={field.value} onValueChange={field.onChange}>
+                      <FormControl>
+                        <SelectTrigger>
+                          <SelectValue />
+                        </SelectTrigger>
+                      </FormControl>
+                      <SelectContent>
+                        {HostStack.options.map((s) => (
+                          <SelectItem key={s} value={s}>
+                            {STACK_LABELS[s]}
+                          </SelectItem>
+                        ))}
+                      </SelectContent>
+                    </Select>
+                    <FormMessage />
+                  </FormItem>
+                )}
+              />
+            </div>
             <FormField
               control={form.control}
               name="notes"
diff --git a/apps/web/src/components/locations/RoomDrawer.tsx b/apps/web/src/components/locations/RoomDrawer.tsx
deleted file mode 100644
index f9a794b..0000000
--- a/apps/web/src/components/locations/RoomDrawer.tsx
+++ /dev/null
@@ -1,204 +0,0 @@
-import { useState } from 'react';
-import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
-import { toast } from 'sonner';
-import { DoorOpen, MoreHorizontal, Plus, Trash2 } from 'lucide-react';
-import {
-  Button,
-  DropdownMenu,
-  DropdownMenuContent,
-  DropdownMenuItem,
-  DropdownMenuTrigger,
-  Skeleton,
-  cn,
-} from '@vector/ui';
-import { createRoom, deleteRoom, listRooms, updateRoom } from '../../lib/api/rooms.js';
-import { ApiRequestError } from '../../lib/api/client.js';
-import { queryKeys } from '../../lib/queryKeys.js';
-import { NamePromptDialog } from '../NamePromptDialog.js';
-import { ConfirmDialog } from '../ConfirmDialog.js';
-import type { Room } from '../../lib/api/types.js';
-
-interface RoomDrawerProps {
-  siteId: string | null;
-  selectedId: string | null;
-  onSelect: (id: string) => void;
-  canEdit: boolean;
-}
-
-export function RoomDrawer({ siteId, selectedId, onSelect, canEdit }: RoomDrawerProps) {
-  const queryClient = useQueryClient();
-  const [creating, setCreating] = useState(false);
-  const [renaming, setRenaming] = useState<Room | null>(null);
-  const [deleting, setDeleting] = useState<Room | null>(null);
-
-  const rooms = useQuery({
-    queryKey: queryKeys.rooms.list({ siteId, pageSize: 100 }),
-    queryFn: () => listRooms({ siteId: siteId!, pageSize: 100 }),
-    enabled: Boolean(siteId),
-  });
-
-  const invalidate = () =>
-    queryClient.invalidateQueries({ queryKey: queryKeys.rooms.all });
-
-  const createMutation = useMutation({
-    mutationFn: (name: string) => createRoom({ name, siteId: siteId! }),
-    onSuccess: (r) => {
-      toast.success('Room created');
-      invalidate();
-      setCreating(false);
-      onSelect(r.id);
-    },
-    onError: (err) =>
-      toast.error(err instanceof ApiRequestError ? err.body.message : 'Create failed'),
-  });
-
-  const renameMutation = useMutation({
-    mutationFn: (vars: { id: string; name: string }) => updateRoom(vars.id, { name: vars.name }),
-    onSuccess: () => {
-      toast.success('Room renamed');
-      invalidate();
-      setRenaming(null);
-    },
-    onError: (err) =>
-      toast.error(err instanceof ApiRequestError ? err.body.message : 'Rename failed'),
-  });
-
-  const deleteMutation = useMutation({
-    mutationFn: (id: string) => deleteRoom(id),
-    onSuccess: (_, id) => {
-      toast.success('Room deleted');
-      invalidate();
-      queryClient.invalidateQueries({ queryKey: queryKeys.bins.all });
-      setDeleting(null);
-      if (selectedId === id) onSelect('');
-    },
-    onError: (err) =>
-      toast.error(err instanceof ApiRequestError ? err.body.message : 'Delete failed'),
-  });
-
-  if (!siteId) {
-    return (
-      <div className="flex h-full items-center justify-center p-6 text-sm text-muted-foreground">
-        Select a site to see its rooms.
-      </div>
-    );
-  }
-
-  return (
-    <div className="flex h-full flex-col">
-      <div className="flex items-center justify-between px-3 py-2">
-        <h2 className="text-xs font-semibold uppercase tracking-wider text-muted-foreground">
-          Rooms
-        </h2>
-        {canEdit && (
-          <Button variant="ghost" size="icon" className="h-7 w-7" onClick={() => setCreating(true)}>
-            <Plus className="h-4 w-4" />
-          </Button>
-        )}
-      </div>
-
-      <div className="flex-1 overflow-y-auto px-2 pb-2">
-        {rooms.isPending ? (
-          <div className="space-y-2 px-1">
-            {Array.from({ length: 3 }).map((_, i) => (
-              <Skeleton key={i} className="h-8 w-full" />
-            ))}
-          </div>
-        ) : rooms.isError ? (
-          <p className="px-3 text-xs text-destructive">Failed to load rooms.</p>
-        ) : rooms.data && rooms.data.data.length === 0 ? (
-          <div className="flex flex-col items-center gap-1 py-6 text-muted-foreground">
-            <DoorOpen className="h-5 w-5" />
-            <span className="text-xs">No rooms in this site</span>
-          </div>
-        ) : (
-          <ul className="space-y-0.5">
-            {rooms.data!.data.map((r) => {
-              const active = r.id === selectedId;
-              return (
-                <li key={r.id}>
-                  <div
-                    className={cn(
-                      'group flex items-center justify-between rounded-md px-2 py-1.5 text-sm',
-                      active
-                        ? 'bg-accent text-accent-foreground'
-                        : 'text-foreground hover:bg-accent/60',
-                    )}
-                  >
-                    <button
-                      type="button"
-                      onClick={() => onSelect(r.id)}
-                      className="flex flex-1 items-center gap-2 text-left"
-                    >
-                      <DoorOpen className="h-4 w-4 opacity-70" />
-                      <span className="truncate">{r.name}</span>
-                    </button>
-                    {canEdit && (
-                      <DropdownMenu>
-                        <DropdownMenuTrigger asChild>
-                          <Button
-                            variant="ghost"
-                            size="icon"
-                            className="h-6 w-6 opacity-0 group-hover:opacity-100 data-[state=open]:opacity-100"
-                          >
-                            <MoreHorizontal className="h-3.5 w-3.5" />
-                          </Button>
-                        </DropdownMenuTrigger>
-                        <DropdownMenuContent align="end" className="w-36">
-                          <DropdownMenuItem onSelect={() => setRenaming(r)}>
-                            Rename
-                          </DropdownMenuItem>
-                          <DropdownMenuItem
-                            onSelect={() => setDeleting(r)}
-                            className="text-destructive focus:text-destructive"
-                          >
-                            <Trash2 className="h-3.5 w-3.5" />
-                            Delete
-                          </DropdownMenuItem>
-                        </DropdownMenuContent>
-                      </DropdownMenu>
-                    )}
-                  </div>
-                </li>
-              );
-            })}
-          </ul>
-        )}
-      </div>
-
-      <NamePromptDialog
-        open={creating}
-        onOpenChange={setCreating}
-        title="New room"
-        label="Room name"
-        confirmLabel="Create"
-        pending={createMutation.isPending}
-        onSubmit={(name) => createMutation.mutate(name)}
-      />
-      <NamePromptDialog
-        open={Boolean(renaming)}
-        onOpenChange={(o) => !o && setRenaming(null)}
-        title="Rename room"
-        label="Room name"
-        confirmLabel="Rename"
-        initialValue={renaming?.name ?? ''}
-        pending={renameMutation.isPending}
-        onSubmit={(name) => renaming && renameMutation.mutate({ id: renaming.id, name })}
-      />
-      <ConfirmDialog
-        open={Boolean(deleting)}
-        onOpenChange={(o) => !o && setDeleting(null)}
-        title="Delete room?"
-        description={
-          deleting
-            ? `Remove ${deleting.name}. All bins inside will be deleted too. Parts in those bins become unassigned.`
-            : undefined
-        }
-        confirmLabel="Delete"
-        destructive
-        pending={deleteMutation.isPending}
-        onConfirm={() => deleting && deleteMutation.mutate(deleting.id)}
-      />
-    </div>
-  );
-}
diff --git a/apps/web/src/components/locations/SiteList.tsx b/apps/web/src/components/locations/SiteList.tsx
deleted file mode 100644
index 1032ee4..0000000
--- a/apps/web/src/components/locations/SiteList.tsx
+++ /dev/null
@@ -1,195 +0,0 @@
-import { useState } from 'react';
-import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
-import { toast } from 'sonner';
-import { Building2, MoreHorizontal, Plus, Trash2 } from 'lucide-react';
-import {
-  Button,
-  DropdownMenu,
-  DropdownMenuContent,
-  DropdownMenuItem,
-  DropdownMenuTrigger,
-  Skeleton,
-  cn,
-} from '@vector/ui';
-import { createSite, deleteSite, listSites, updateSite } from '../../lib/api/sites.js';
-import { ApiRequestError } from '../../lib/api/client.js';
-import { queryKeys } from '../../lib/queryKeys.js';
-import { NamePromptDialog } from '../NamePromptDialog.js';
-import { ConfirmDialog } from '../ConfirmDialog.js';
-import type { Site } from '../../lib/api/types.js';
-
-interface SiteListProps {
-  selectedId: string | null;
-  onSelect: (id: string) => void;
-  canEdit: boolean;
-}
-
-export function SiteList({ selectedId, onSelect, canEdit }: SiteListProps) {
-  const queryClient = useQueryClient();
-  const [creating, setCreating] = useState(false);
-  const [renaming, setRenaming] = useState<Site | null>(null);
-  const [deleting, setDeleting] = useState<Site | null>(null);
-
-  const sites = useQuery({
-    queryKey: queryKeys.sites.list({ pageSize: 100 }),
-    queryFn: () => listSites({ pageSize: 100 }),
-  });
-
-  const invalidate = () =>
-    queryClient.invalidateQueries({ queryKey: queryKeys.sites.all });
-
-  const createMutation = useMutation({
-    mutationFn: (name: string) => createSite({ name }),
-    onSuccess: (s) => {
-      toast.success('Site created');
-      invalidate();
-      setCreating(false);
-      onSelect(s.id);
-    },
-    onError: (err) =>
-      toast.error(err instanceof ApiRequestError ? err.body.message : 'Create failed'),
-  });
-
-  const renameMutation = useMutation({
-    mutationFn: (vars: { id: string; name: string }) => updateSite(vars.id, { name: vars.name }),
-    onSuccess: () => {
-      toast.success('Site renamed');
-      invalidate();
-      setRenaming(null);
-    },
-    onError: (err) =>
-      toast.error(err instanceof ApiRequestError ? err.body.message : 'Rename failed'),
-  });
-
-  const deleteMutation = useMutation({
-    mutationFn: (id: string) => deleteSite(id),
-    onSuccess: (_, id) => {
-      toast.success('Site deleted');
-      invalidate();
-      queryClient.invalidateQueries({ queryKey: queryKeys.rooms.all });
-      queryClient.invalidateQueries({ queryKey: queryKeys.bins.all });
-      setDeleting(null);
-      if (selectedId === id) onSelect('');
-    },
-    onError: (err) =>
-      toast.error(err instanceof ApiRequestError ? err.body.message : 'Delete failed'),
-  });
-
-  return (
-    <div className="flex h-full flex-col">
-      <div className="flex items-center justify-between px-3 py-2">
-        <h2 className="text-xs font-semibold uppercase tracking-wider text-muted-foreground">
-          Sites
-        </h2>
-        {canEdit && (
-          <Button variant="ghost" size="icon" className="h-7 w-7" onClick={() => setCreating(true)}>
-            <Plus className="h-4 w-4" />
-          </Button>
-        )}
-      </div>
-
-      <div className="flex-1 overflow-y-auto px-2 pb-2">
-        {sites.isPending ? (
-          <div className="space-y-2 px-1">
-            {Array.from({ length: 4 }).map((_, i) => (
-              <Skeleton key={i} className="h-8 w-full" />
-            ))}
-          </div>
-        ) : sites.isError ? (
-          <p className="px-3 text-xs text-destructive">Failed to load sites.</p>
-        ) : sites.data && sites.data.data.length === 0 ? (
-          <div className="flex flex-col items-center gap-1 py-6 text-muted-foreground">
-            <Building2 className="h-5 w-5" />
-            <span className="text-xs">No sites yet</span>
-          </div>
-        ) : (
-          <ul className="space-y-0.5">
-            {sites.data!.data.map((s) => {
-              const active = s.id === selectedId;
-              return (
-                <li key={s.id}>
-                  <div
-                    className={cn(
-                      'group flex items-center justify-between rounded-md px-2 py-1.5 text-sm',
-                      active
-                        ? 'bg-accent text-accent-foreground'
-                        : 'text-foreground hover:bg-accent/60',
-                    )}
-                  >
-                    <button
-                      type="button"
-                      onClick={() => onSelect(s.id)}
-                      className="flex flex-1 items-center gap-2 text-left"
-                    >
-                      <Building2 className="h-4 w-4 opacity-70" />
-                      <span className="truncate">{s.name}</span>
-                    </button>
-                    {canEdit && (
-                      <DropdownMenu>
-                        <DropdownMenuTrigger asChild>
-                          <Button
-                            variant="ghost"
-                            size="icon"
-                            className="h-6 w-6 opacity-0 group-hover:opacity-100 data-[state=open]:opacity-100"
-                          >
-                            <MoreHorizontal className="h-3.5 w-3.5" />
-                          </Button>
-                        </DropdownMenuTrigger>
-                        <DropdownMenuContent align="end" className="w-36">
-                          <DropdownMenuItem onSelect={() => setRenaming(s)}>
-                            Rename
-                          </DropdownMenuItem>
-                          <DropdownMenuItem
-                            onSelect={() => setDeleting(s)}
-                            className="text-destructive focus:text-destructive"
-                          >
-                            <Trash2 className="h-3.5 w-3.5" />
-                            Delete
-                          </DropdownMenuItem>
-                        </DropdownMenuContent>
-                      </DropdownMenu>
-                    )}
-                  </div>
-                </li>
-              );
-            })}
-          </ul>
-        )}
-      </div>
-
-      <NamePromptDialog
-        open={creating}
-        onOpenChange={setCreating}
-        title="New site"
-        label="Site name"
-        confirmLabel="Create"
-        pending={createMutation.isPending}
-        onSubmit={(name) => createMutation.mutate(name)}
-      />
-      <NamePromptDialog
-        open={Boolean(renaming)}
-        onOpenChange={(o) => !o && setRenaming(null)}
-        title="Rename site"
-        label="Site name"
-        confirmLabel="Rename"
-        initialValue={renaming?.name ?? ''}
-        pending={renameMutation.isPending}
-        onSubmit={(name) => renaming && renameMutation.mutate({ id: renaming.id, name })}
-      />
-      <ConfirmDialog
-        open={Boolean(deleting)}
-        onOpenChange={(o) => !o && setDeleting(null)}
-        title="Delete site?"
-        description={
-          deleting
-            ? `Remove ${deleting.name}. All rooms and bins inside will be deleted too. Parts in those bins become unassigned.`
-            : undefined
-        }
-        confirmLabel="Delete"
-        destructive
-        pending={deleteMutation.isPending}
-        onConfirm={() => deleting && deleteMutation.mutate(deleting.id)}
-      />
-    </div>
-  );
-}
diff --git a/apps/web/src/components/locations/SiteRoomTree.tsx b/apps/web/src/components/locations/SiteRoomTree.tsx
new file mode 100644
index 0000000..e2a9279
--- /dev/null
+++ b/apps/web/src/components/locations/SiteRoomTree.tsx
@@ -0,0 +1,434 @@
+import { useEffect, useMemo, useState } from 'react';
+import { useMutation, useQueries, useQuery, useQueryClient } from '@tanstack/react-query';
+import { toast } from 'sonner';
+import {
+  Building2,
+  ChevronDown,
+  ChevronRight,
+  DoorOpen,
+  MoreHorizontal,
+  Plus,
+  Trash2,
+} from 'lucide-react';
+import {
+  Button,
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+  Skeleton,
+  cn,
+} from '@vector/ui';
+import { createSite, deleteSite, listSites, updateSite } from '../../lib/api/sites.js';
+import { createRoom, deleteRoom, listRooms, updateRoom } from '../../lib/api/rooms.js';
+import { ApiRequestError } from '../../lib/api/client.js';
+import { queryKeys } from '../../lib/queryKeys.js';
+import { NamePromptDialog } from '../NamePromptDialog.js';
+import { ConfirmDialog } from '../ConfirmDialog.js';
+import type { Room, Site } from '../../lib/api/types.js';
+
+// A single tree view combining the former SiteList and RoomDrawer. Sites expand to show their
+// rooms inline; the whole thing shares the same URL state (?site=&room=) so deep links still
+// resolve. Each row keeps its inline rename/delete action; creation happens per level.
+interface SiteRoomTreeProps {
+  siteId: string | null;
+  roomId: string | null;
+  onSelectSite: (id: string) => void;
+  onSelectRoom: (id: string) => void;
+  canEdit: boolean;
+}
+
+type RenameTarget = { kind: 'site'; value: Site } | { kind: 'room'; value: Room };
+type DeleteTarget = { kind: 'site'; value: Site } | { kind: 'room'; value: Room };
+
+export function SiteRoomTree({
+  siteId,
+  roomId,
+  onSelectSite,
+  onSelectRoom,
+  canEdit,
+}: SiteRoomTreeProps) {
+  const queryClient = useQueryClient();
+
+  const [creatingSite, setCreatingSite] = useState(false);
+  const [creatingRoomInSite, setCreatingRoomInSite] = useState<string | null>(null);
+  const [renaming, setRenaming] = useState<RenameTarget | null>(null);
+  const [deleting, setDeleting] = useState<DeleteTarget | null>(null);
+  const [expanded, setExpanded] = useState<Set<string>>(new Set());
+
+  const sites = useQuery({
+    queryKey: queryKeys.sites.list({ pageSize: 100 }),
+    queryFn: () => listSites({ pageSize: 100 }),
+  });
+
+  // Ensure the selected site is expanded on load / deep link.
+  useEffect(() => {
+    if (siteId) setExpanded((prev) => (prev.has(siteId) ? prev : new Set(prev).add(siteId)));
+  }, [siteId]);
+
+  const siteIds = useMemo(() => {
+    const list = sites.data?.data ?? [];
+    return list.filter((s) => expanded.has(s.id)).map((s) => s.id);
+  }, [sites.data, expanded]);
+
+  const roomQueries = useQueries({
+    queries: siteIds.map((id) => ({
+      queryKey: queryKeys.rooms.list({ siteId: id, pageSize: 100 }),
+      queryFn: () => listRooms({ siteId: id, pageSize: 100 }),
+    })),
+  });
+  const roomsBySite = useMemo(() => {
+    const m = new Map<string, Room[]>();
+    siteIds.forEach((id, i) => {
+      m.set(id, roomQueries[i]?.data?.data ?? []);
+    });
+    return m;
+  }, [siteIds, roomQueries]);
+
+  const invalidateSites = () =>
+    queryClient.invalidateQueries({ queryKey: queryKeys.sites.all });
+  const invalidateRooms = () =>
+    queryClient.invalidateQueries({ queryKey: queryKeys.rooms.all });
+
+  const createSiteMutation = useMutation({
+    mutationFn: (name: string) => createSite({ name }),
+    onSuccess: (s) => {
+      toast.success('Site created');
+      invalidateSites();
+      setCreatingSite(false);
+      setExpanded((prev) => new Set(prev).add(s.id));
+      onSelectSite(s.id);
+    },
+    onError: (err) =>
+      toast.error(err instanceof ApiRequestError ? err.body.message : 'Create failed'),
+  });
+
+  const createRoomMutation = useMutation({
+    mutationFn: (vars: { siteId: string; name: string }) =>
+      createRoom({ name: vars.name, siteId: vars.siteId }),
+    onSuccess: (r) => {
+      toast.success('Room created');
+      invalidateRooms();
+      setCreatingRoomInSite(null);
+      onSelectRoom(r.id);
+    },
+    onError: (err) =>
+      toast.error(err instanceof ApiRequestError ? err.body.message : 'Create failed'),
+  });
+
+  const renameSiteMutation = useMutation({
+    mutationFn: (vars: { id: string; name: string }) => updateSite(vars.id, { name: vars.name }),
+    onSuccess: () => {
+      toast.success('Site renamed');
+      invalidateSites();
+      setRenaming(null);
+    },
+    onError: (err) =>
+      toast.error(err instanceof ApiRequestError ? err.body.message : 'Rename failed'),
+  });
+
+  const renameRoomMutation = useMutation({
+    mutationFn: (vars: { id: string; name: string }) => updateRoom(vars.id, { name: vars.name }),
+    onSuccess: () => {
+      toast.success('Room renamed');
+      invalidateRooms();
+      setRenaming(null);
+    },
+    onError: (err) =>
+      toast.error(err instanceof ApiRequestError ? err.body.message : 'Rename failed'),
+  });
+
+  const deleteSiteMutation = useMutation({
+    mutationFn: (id: string) => deleteSite(id),
+    onSuccess: (_, id) => {
+      toast.success('Site deleted');
+      invalidateSites();
+      invalidateRooms();
+      queryClient.invalidateQueries({ queryKey: queryKeys.bins.all });
+      setDeleting(null);
+      if (siteId === id) onSelectSite('');
+    },
+    onError: (err) =>
+      toast.error(err instanceof ApiRequestError ? err.body.message : 'Delete failed'),
+  });
+
+  const deleteRoomMutation = useMutation({
+    mutationFn: (id: string) => deleteRoom(id),
+    onSuccess: (_, id) => {
+      toast.success('Room deleted');
+      invalidateRooms();
+      queryClient.invalidateQueries({ queryKey: queryKeys.bins.all });
+      setDeleting(null);
+      if (roomId === id) onSelectRoom('');
+    },
+    onError: (err) =>
+      toast.error(err instanceof ApiRequestError ? err.body.message : 'Delete failed'),
+  });
+
+  const toggle = (id: string) => {
+    setExpanded((prev) => {
+      const next = new Set(prev);
+      if (next.has(id)) next.delete(id);
+      else next.add(id);
+      return next;
+    });
+  };
+
+  const hasSites = Boolean(sites.data && sites.data.data.length > 0);
+
+  return (
+    <div className="flex h-full flex-col">
+      <div className="flex items-center justify-between px-3 py-2">
+        <h2 className="text-xs font-semibold uppercase tracking-wider text-muted-foreground">
+          Sites
+        </h2>
+        {canEdit && hasSites && (
+          <Button
+            variant="ghost"
+            size="icon"
+            className="h-7 w-7"
+            onClick={() => setCreatingSite(true)}
+            aria-label="Add site"
+          >
+            <Plus className="h-4 w-4" />
+          </Button>
+        )}
+      </div>
+
+      <div className="flex-1 overflow-y-auto px-2 pb-2">
+        {sites.isPending ? (
+          <div className="space-y-2 px-1">
+            {Array.from({ length: 4 }).map((_, i) => (
+              <Skeleton key={i} className="h-8 w-full" />
+            ))}
+          </div>
+        ) : sites.isError ? (
+          <p className="px-3 text-xs text-destructive">Failed to load sites.</p>
+        ) : !hasSites ? (
+          <div className="flex flex-col items-center gap-2 py-8 text-muted-foreground">
+            <Building2 className="h-5 w-5" />
+            <span className="text-xs">No sites yet</span>
+            {canEdit && (
+              <Button size="sm" variant="outline" onClick={() => setCreatingSite(true)}>
+                <Plus className="h-3.5 w-3.5" />
+                Add site
+              </Button>
+            )}
+          </div>
+        ) : (
+          <ul className="space-y-0.5">
+            {sites.data!.data.map((s) => {
+              const isOpen = expanded.has(s.id);
+              const siteActive = s.id === siteId;
+              const rooms = roomsBySite.get(s.id) ?? [];
+              return (
+                <li key={s.id}>
+                  <div
+                    className={cn(
+                      'group flex items-center rounded-md text-sm',
+                      siteActive
+                        ? 'bg-accent text-accent-foreground'
+                        : 'text-foreground hover:bg-accent/60',
+                    )}
+                  >
+                    <button
+                      type="button"
+                      onClick={() => toggle(s.id)}
+                      className="flex h-8 w-7 items-center justify-center text-muted-foreground"
+                      aria-label={isOpen ? 'Collapse' : 'Expand'}
+                    >
+                      {isOpen ? (
+                        <ChevronDown className="h-3.5 w-3.5" />
+                      ) : (
+                        <ChevronRight className="h-3.5 w-3.5" />
+                      )}
+                    </button>
+                    <button
+                      type="button"
+                      onClick={() => {
+                        onSelectSite(s.id);
+                        setExpanded((prev) => new Set(prev).add(s.id));
+                      }}
+                      className="flex flex-1 items-center gap-2 py-1.5 text-left"
+                    >
+                      <Building2 className="h-4 w-4 opacity-70" />
+                      <span className="truncate">{s.name}</span>
+                    </button>
+                    {canEdit && (
+                      <DropdownMenu>
+                        <DropdownMenuTrigger asChild>
+                          <Button
+                            variant="ghost"
+                            size="icon"
+                            className="mr-1 h-6 w-6 opacity-0 group-hover:opacity-100 data-[state=open]:opacity-100"
+                          >
+                            <MoreHorizontal className="h-3.5 w-3.5" />
+                          </Button>
+                        </DropdownMenuTrigger>
+                        <DropdownMenuContent align="end" className="w-40">
+                          <DropdownMenuItem
+                            onSelect={() => setCreatingRoomInSite(s.id)}
+                          >
+                            <Plus className="h-3.5 w-3.5" />
+                            Add room
+                          </DropdownMenuItem>
+                          <DropdownMenuItem
+                            onSelect={() => setRenaming({ kind: 'site', value: s })}
+                          >
+                            Rename
+                          </DropdownMenuItem>
+                          <DropdownMenuItem
+                            onSelect={() => setDeleting({ kind: 'site', value: s })}
+                            className="text-destructive focus:text-destructive"
+                          >
+                            <Trash2 className="h-3.5 w-3.5" />
+                            Delete
+                          </DropdownMenuItem>
+                        </DropdownMenuContent>
+                      </DropdownMenu>
+                    )}
+                  </div>
+
+                  {isOpen && (
+                    <ul className="ml-6 mt-0.5 space-y-0.5 border-l border-border pl-1">
+                      {rooms.length === 0 ? (
+                        <li className="px-2 py-1 text-xs text-muted-foreground">
+                          No rooms yet
+                          {canEdit && (
+                            <Button
+                              variant="link"
+                              size="sm"
+                              className="h-auto px-1.5 py-0 text-xs"
+                              onClick={() => setCreatingRoomInSite(s.id)}
+                            >
+                              + add
+                            </Button>
+                          )}
+                        </li>
+                      ) : (
+                        rooms.map((r) => {
+                          const roomActive = r.id === roomId;
+                          return (
+                            <li key={r.id}>
+                              <div
+                                className={cn(
+                                  'group flex items-center rounded-md text-sm',
+                                  roomActive
+                                    ? 'bg-accent text-accent-foreground'
+                                    : 'text-foreground hover:bg-accent/60',
+                                )}
+                              >
+                                <button
+                                  type="button"
+                                  onClick={() => onSelectRoom(r.id)}
+                                  className="flex flex-1 items-center gap-2 py-1.5 pl-2 text-left"
+                                >
+                                  <DoorOpen className="h-3.5 w-3.5 opacity-70" />
+                                  <span className="truncate">{r.name}</span>
+                                </button>
+                                {canEdit && (
+                                  <DropdownMenu>
+                                    <DropdownMenuTrigger asChild>
+                                      <Button
+                                        variant="ghost"
+                                        size="icon"
+                                        className="mr-1 h-6 w-6 opacity-0 group-hover:opacity-100 data-[state=open]:opacity-100"
+                                      >
+                                        <MoreHorizontal className="h-3.5 w-3.5" />
+                                      </Button>
+                                    </DropdownMenuTrigger>
+                                    <DropdownMenuContent align="end" className="w-36">
+                                      <DropdownMenuItem
+                                        onSelect={() =>
+                                          setRenaming({ kind: 'room', value: r })
+                                        }
+                                      >
+                                        Rename
+                                      </DropdownMenuItem>
+                                      <DropdownMenuItem
+                                        onSelect={() =>
+                                          setDeleting({ kind: 'room', value: r })
+                                        }
+                                        className="text-destructive focus:text-destructive"
+                                      >
+                                        <Trash2 className="h-3.5 w-3.5" />
+                                        Delete
+                                      </DropdownMenuItem>
+                                    </DropdownMenuContent>
+                                  </DropdownMenu>
+                                )}
+                              </div>
+                            </li>
+                          );
+                        })
+                      )}
+                    </ul>
+                  )}
+                </li>
+              );
+            })}
+          </ul>
+        )}
+      </div>
+
+      <NamePromptDialog
+        open={creatingSite}
+        onOpenChange={setCreatingSite}
+        title="New site"
+        label="Site name"
+        confirmLabel="Create"
+        pending={createSiteMutation.isPending}
+        onSubmit={(name) => createSiteMutation.mutate(name)}
+      />
+      <NamePromptDialog
+        open={Boolean(creatingRoomInSite)}
+        onOpenChange={(o) => !o && setCreatingRoomInSite(null)}
+        title="New room"
+        label="Room name"
+        confirmLabel="Create"
+        pending={createRoomMutation.isPending}
+        onSubmit={(name) =>
+          creatingRoomInSite &&
+          createRoomMutation.mutate({ siteId: creatingRoomInSite, name })
+        }
+      />
+      <NamePromptDialog
+        open={Boolean(renaming)}
+        onOpenChange={(o) => !o && setRenaming(null)}
+        title={renaming?.kind === 'site' ? 'Rename site' : 'Rename room'}
+        label={renaming?.kind === 'site' ? 'Site name' : 'Room name'}
+        confirmLabel="Rename"
+        initialValue={renaming?.value.name ?? ''}
+        pending={renameSiteMutation.isPending || renameRoomMutation.isPending}
+        onSubmit={(name) => {
+          if (!renaming) return;
+          if (renaming.kind === 'site') {
+            renameSiteMutation.mutate({ id: renaming.value.id, name });
+          } else {
+            renameRoomMutation.mutate({ id: renaming.value.id, name });
+          }
+        }}
+      />
+      <ConfirmDialog
+        open={Boolean(deleting)}
+        onOpenChange={(o) => !o && setDeleting(null)}
+        title={deleting?.kind === 'site' ? 'Delete site?' : 'Delete room?'}
+        description={
+          deleting
+            ? deleting.kind === 'site'
+              ? `Remove ${deleting.value.name}. All rooms and bins inside will be deleted too. Parts in those bins become unassigned.`
+              : `Remove ${deleting.value.name}. All bins inside will be deleted too. Parts in those bins become unassigned.`
+            : undefined
+        }
+        confirmLabel="Delete"
+        destructive
+        pending={deleteSiteMutation.isPending || deleteRoomMutation.isPending}
+        onConfirm={() => {
+          if (!deleting) return;
+          if (deleting.kind === 'site') deleteSiteMutation.mutate(deleting.value.id);
+          else deleteRoomMutation.mutate(deleting.value.id);
+        }}
+      />
+    </div>
+  );
+}
diff --git a/apps/web/src/components/part-models/PartModelFormDialog.tsx b/apps/web/src/components/part-models/PartModelFormDialog.tsx
index 52772c1..22cb022 100644
--- a/apps/web/src/components/part-models/PartModelFormDialog.tsx
+++ b/apps/web/src/components/part-models/PartModelFormDialog.tsx
@@ -31,6 +31,7 @@ import {
 } from '@vector/ui';
 import { createPartModel, updatePartModel } from '../../lib/api/part-models.js';
 import { listManufacturers } from '../../lib/api/manufacturers.js';
+import { createCategory, listCategories } from '../../lib/api/categories.js';
 import { ApiRequestError } from '../../lib/api/client.js';
 import { queryKeys } from '../../lib/queryKeys.js';
 import type { PartModel } from '../../lib/api/types.js';
@@ -38,6 +39,7 @@ import type { PartModel } from '../../lib/api/types.js';
 const Schema = z.object({
   manufacturerId: z.string().uuid('Pick a manufacturer'),
   mpn: z.string().min(1, 'Required').max(128),
+  categoryId: z.string().optional(), // '' = unassigned
   eolDate: z
     .string()
     .regex(/^\d{4}-\d{2}-\d{2}$/, 'YYYY-MM-DD')
@@ -48,6 +50,8 @@ const Schema = z.object({
 });
 type Values = z.infer<typeof Schema>;
 
+const UNASSIGNED = '__none__';
+
 function isoToDateInput(iso: string | null): string {
   if (!iso) return '';
   return new Date(iso).toISOString().slice(0, 10);
@@ -72,6 +76,7 @@ export function PartModelFormDialog({
     defaultValues: {
       manufacturerId: '',
       mpn: '',
+      categoryId: '',
       eolDate: '',
       destroyOnFail: false,
       notes: '',
@@ -83,6 +88,7 @@ export function PartModelFormDialog({
     form.reset({
       manufacturerId: partModel?.manufacturerId ?? '',
       mpn: partModel?.mpn ?? '',
+      categoryId: partModel?.categoryId ?? '',
       eolDate: isoToDateInput(partModel?.eolDate ?? null),
       destroyOnFail: partModel?.destroyOnFail ?? false,
       notes: partModel?.notes ?? '',
@@ -95,11 +101,28 @@ export function PartModelFormDialog({
     enabled: open,
   });
 
+  const categories = useQuery({
+    queryKey: queryKeys.categories.list({ pageSize: 100 }),
+    queryFn: () => listCategories({ pageSize: 100 }),
+    enabled: open,
+  });
+
+  const createCategoryMutation = useMutation({
+    mutationFn: (name: string) => createCategory({ name }),
+    onSuccess: (cat) => {
+      queryClient.invalidateQueries({ queryKey: queryKeys.categories.all });
+      form.setValue('categoryId', cat.id);
+    },
+    onError: (err) =>
+      toast.error(err instanceof ApiRequestError ? err.body.message : 'Could not add category'),
+  });
+
   const mutation = useMutation({
     mutationFn: async (values: Values) => {
       const payload = {
         manufacturerId: values.manufacturerId,
         mpn: values.mpn,
+        categoryId: values.categoryId ? values.categoryId : null,
         eolDate: values.eolDate ? values.eolDate : null,
         destroyOnFail: values.destroyOnFail,
         notes: values.notes ? values.notes : null,
@@ -166,6 +189,47 @@ export function PartModelFormDialog({
                 </FormItem>
               )}
             />
+            <FormField
+              control={form.control}
+              name="categoryId"
+              render={({ field }) => (
+                <FormItem>
+                  <FormLabel>Category</FormLabel>
+                  <div className="flex items-center gap-2">
+                    <Select
+                      value={field.value ? field.value : UNASSIGNED}
+                      onValueChange={(v) => {
+                        if (v === '__new__') {
+                          const name = window.prompt('New category name')?.trim();
+                          if (name) createCategoryMutation.mutate(name);
+                          return;
+                        }
+                        field.onChange(v === UNASSIGNED ? '' : v);
+                      }}
+                    >
+                      <FormControl>
+                        <SelectTrigger>
+                          <SelectValue placeholder="Unassigned" />
+                        </SelectTrigger>
+                      </FormControl>
+                      <SelectContent>
+                        <SelectItem value={UNASSIGNED}>Unassigned</SelectItem>
+                        {categories.data?.data.map((c) => (
+                          <SelectItem key={c.id} value={c.id}>
+                            {c.name}
+                          </SelectItem>
+                        ))}
+                        <SelectItem value="__new__">+ Add category…</SelectItem>
+                      </SelectContent>
+                    </Select>
+                  </div>
+                  <FormDescription>
+                    Groups like GPU / RAM / SSD describe this model family.
+                  </FormDescription>
+                  <FormMessage />
+                </FormItem>
+              )}
+            />
             <FormField
               control={form.control}
               name="eolDate"
diff --git a/apps/web/src/components/parts/PartFormDialog.tsx b/apps/web/src/components/parts/PartFormDialog.tsx
index 05f32e3..db20349 100644
--- a/apps/web/src/components/parts/PartFormDialog.tsx
+++ b/apps/web/src/components/parts/PartFormDialog.tsx
@@ -1,4 +1,4 @@
-import { useEffect } from 'react';
+import { useEffect, useState } from 'react';
 import { useForm } from 'react-hook-form';
 import { zodResolver } from '@hookform/resolvers/zod';
 import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
@@ -6,6 +6,8 @@ import { z } from 'zod';
 import { Loader2 } from 'lucide-react';
 import { toast } from 'sonner';
 import { PartState } from '@vector/shared';
+import { PartModelCombobox } from '../common/PartModelCombobox.js';
+import type { PartModel } from '../../lib/api/types.js';
 import {
   Button,
   Dialog,
@@ -38,12 +40,13 @@ import { queryKeys } from '../../lib/queryKeys.js';
 import { partStateOptions } from './PartStateBadge.js';
 
 // Schema reflects the server's CreatePartRequest but keeps strings for the form, letting the
-// submit handler coerce to the network shape.
+// submit handler coerce to the network shape. The combobox drives partModelId xor (mpn+mfr).
 const PartFormSchema = z
   .object({
     serialNumber: z.string().min(1, 'Required').max(128),
-    mpn: z.string().min(1, 'Required').max(128),
-    manufacturerId: z.string().uuid('Select a manufacturer'),
+    partModelId: z.string().optional(), // set when an existing model is picked
+    mpn: z.string().max(128).optional(), // set when creating a new model
+    manufacturerId: z.string().optional(),
     state: PartState,
     binId: z.string().optional(), // '' = none
     hostId: z.string().optional(), // '' = none
@@ -51,6 +54,22 @@ const PartFormSchema = z
     notes: z.string().max(4096).optional(),
   })
   .superRefine((v, ctx) => {
+    const hasModel = Boolean(v.partModelId);
+    const hasNew = Boolean(v.mpn && v.mpn.length > 0);
+    if (!hasModel && !hasNew) {
+      ctx.addIssue({
+        code: z.ZodIssueCode.custom,
+        message: 'Pick a part model or enter a new MPN',
+        path: ['partModelId'],
+      });
+    }
+    if (hasNew && !v.manufacturerId) {
+      ctx.addIssue({
+        code: z.ZodIssueCode.custom,
+        message: 'Select a manufacturer for the new model',
+        path: ['manufacturerId'],
+      });
+    }
     if (v.state === 'DEPLOYED' && !v.hostId) {
       ctx.addIssue({
         code: z.ZodIssueCode.custom,
@@ -73,10 +92,13 @@ export function PartFormDialog({ open, onOpenChange, part }: PartFormDialogProps
   const editing = Boolean(part);
   const queryClient = useQueryClient();
 
+  const [pickedModel, setPickedModel] = useState<PartModel | null>(null);
+
   const form = useForm<PartFormValues>({
     resolver: zodResolver(PartFormSchema),
     defaultValues: {
       serialNumber: '',
+      partModelId: '',
       mpn: '',
       manufacturerId: '',
       state: 'SPARE',
@@ -89,29 +111,33 @@ export function PartFormDialog({ open, onOpenChange, part }: PartFormDialogProps
 
   useEffect(() => {
     if (!open) return;
-    form.reset(
-      part
-        ? {
-            serialNumber: part.serialNumber,
-            mpn: part.partModel.mpn,
-            manufacturerId: part.manufacturerId,
-            state: part.state,
-            binId: part.binId ?? '',
-            hostId: part.hostId ?? '',
-            price: part.price != null ? String(part.price) : '',
-            notes: part.notes ?? '',
-          }
-        : {
-            serialNumber: '',
-            mpn: '',
-            manufacturerId: '',
-            state: 'SPARE',
-            binId: '',
-            hostId: '',
-            price: '',
-            notes: '',
-          },
-    );
+    if (part) {
+      setPickedModel(part.partModel ?? null);
+      form.reset({
+        serialNumber: part.serialNumber,
+        partModelId: part.partModelId,
+        mpn: '',
+        manufacturerId: '',
+        state: part.state,
+        binId: part.binId ?? '',
+        hostId: part.hostId ?? '',
+        price: part.price != null ? String(part.price) : '',
+        notes: part.notes ?? '',
+      });
+    } else {
+      setPickedModel(null);
+      form.reset({
+        serialNumber: '',
+        partModelId: '',
+        mpn: '',
+        manufacturerId: '',
+        state: 'SPARE',
+        binId: '',
+        hostId: '',
+        price: '',
+        notes: '',
+      });
+    }
   }, [open, part, form]);
 
   const watchedState = form.watch('state');
@@ -137,16 +163,18 @@ export function PartFormDialog({ open, onOpenChange, part }: PartFormDialogProps
   const mutation = useMutation({
     mutationFn: async (values: PartFormValues) => {
       const deployed = values.state === 'DEPLOYED';
-      const payload = {
+      const base = {
         serialNumber: values.serialNumber,
-        mpn: values.mpn,
-        manufacturerId: values.manufacturerId,
         state: values.state,
         binId: deployed ? null : values.binId ? values.binId : null,
         hostId: deployed ? (values.hostId ? values.hostId : null) : null,
         price: values.price === '' ? null : Number(values.price),
         notes: values.notes ? values.notes : null,
       };
+      const modelPayload = values.partModelId
+        ? { partModelId: values.partModelId }
+        : { mpn: values.mpn!, manufacturerId: values.manufacturerId! };
+      const payload = { ...base, ...modelPayload };
       return editing && part
         ? updatePart(part.id, payload)
         : createPart(payload);
@@ -191,60 +219,79 @@ export function PartFormDialog({ open, onOpenChange, part }: PartFormDialogProps
 
         <Form {...form}>
           <form onSubmit={form.handleSubmit(onSubmit)} className="space-y-3">
-            <div className="grid grid-cols-2 gap-3">
-              <FormField
-                control={form.control}
-                name="serialNumber"
-                render={({ field }) => (
-                  <FormItem>
-                    <FormLabel>Serial</FormLabel>
-                    <FormControl>
-                      <Input autoFocus {...field} />
-                    </FormControl>
-                    <FormMessage />
-                  </FormItem>
-                )}
-              />
-              <FormField
-                control={form.control}
-                name="mpn"
-                render={({ field }) => (
-                  <FormItem>
-                    <FormLabel>MPN</FormLabel>
-                    <FormControl>
-                      <Input {...field} />
-                    </FormControl>
-                    <FormMessage />
-                  </FormItem>
-                )}
-              />
-            </div>
-
             <FormField
               control={form.control}
-              name="manufacturerId"
+              name="serialNumber"
               render={({ field }) => (
                 <FormItem>
-                  <FormLabel>Manufacturer</FormLabel>
-                  <Select value={field.value} onValueChange={field.onChange}>
-                    <FormControl>
-                      <SelectTrigger>
-                        <SelectValue placeholder="Select manufacturer" />
-                      </SelectTrigger>
-                    </FormControl>
-                    <SelectContent>
-                      {manufacturers.data?.data.map((m) => (
-                        <SelectItem key={m.id} value={m.id}>
-                          {m.name}
-                        </SelectItem>
-                      ))}
-                    </SelectContent>
-                  </Select>
+                  <FormLabel>Serial</FormLabel>
+                  <FormControl>
+                    <Input autoFocus {...field} />
+                  </FormControl>
                   <FormMessage />
                 </FormItem>
               )}
             />
 
+            <FormField
+              control={form.control}
+              name="partModelId"
+              render={() => (
+                <FormItem>
+                  <FormLabel>Part model</FormLabel>
+                  <PartModelCombobox
+                    value={pickedModel}
+                    newMpn={form.watch('mpn') || null}
+                    onPick={(m) => {
+                      setPickedModel(m);
+                      form.setValue('partModelId', m.id, { shouldValidate: true });
+                      form.setValue('mpn', '');
+                      form.setValue('manufacturerId', '');
+                    }}
+                    onCreateNew={(mpn) => {
+                      setPickedModel(null);
+                      form.setValue('partModelId', '');
+                      form.setValue('mpn', mpn, { shouldValidate: true });
+                    }}
+                    onClear={() => {
+                      setPickedModel(null);
+                      form.setValue('partModelId', '');
+                      form.setValue('mpn', '');
+                      form.setValue('manufacturerId', '');
+                    }}
+                  />
+                  <FormMessage />
+                </FormItem>
+              )}
+            />
+
+            {!pickedModel && form.watch('mpn') && (
+              <FormField
+                control={form.control}
+                name="manufacturerId"
+                render={({ field }) => (
+                  <FormItem>
+                    <FormLabel>Manufacturer (for new model)</FormLabel>
+                    <Select value={field.value ?? ''} onValueChange={field.onChange}>
+                      <FormControl>
+                        <SelectTrigger>
+                          <SelectValue placeholder="Select manufacturer" />
+                        </SelectTrigger>
+                      </FormControl>
+                      <SelectContent>
+                        {manufacturers.data?.data.map((m) => (
+                          <SelectItem key={m.id} value={m.id}>
+                            {m.name}
+                          </SelectItem>
+                        ))}
+                      </SelectContent>
+                    </Select>
+                    <FormMessage />
+                  </FormItem>
+                )}
+              />
+            )}
+
             <div className="grid grid-cols-2 gap-3">
               <FormField
                 control={form.control}
diff --git a/apps/web/src/components/parts/PartStateBadge.tsx b/apps/web/src/components/parts/PartStateBadge.tsx
index 50c8dc6..aae0444 100644
--- a/apps/web/src/components/parts/PartStateBadge.tsx
+++ b/apps/web/src/components/parts/PartStateBadge.tsx
@@ -8,6 +8,7 @@ const STATE_LABEL: Record<PartState, string> = {
   PENDING_DESTRUCTION: 'Pending destruction',
   PENDING_DROP_IN_CUSTODY: 'In custody',
   PENDING_DESTRUCTION_IN_CUSTODY: 'In custody (destroy)',
+  PENDING_REPAIR: 'Held for repair',
 };
 
 const STATE_VARIANT: Record<PartState, BadgeProps['variant']> = {
@@ -17,6 +18,7 @@ const STATE_VARIANT: Record<PartState, BadgeProps['variant']> = {
   PENDING_DESTRUCTION: 'destructive',
   PENDING_DROP_IN_CUSTODY: 'outline',
   PENDING_DESTRUCTION_IN_CUSTODY: 'outline',
+  PENDING_REPAIR: 'outline',
 };
 
 export function PartStateBadge({ state }: { state: PartState }) {
diff --git a/apps/web/src/components/repairs/LogRepairDialog.tsx b/apps/web/src/components/repairs/LogRepairDialog.tsx
index ad03cce..e7a008f 100644
--- a/apps/web/src/components/repairs/LogRepairDialog.tsx
+++ b/apps/web/src/components/repairs/LogRepairDialog.tsx
@@ -1,4 +1,4 @@
-import { useEffect } from 'react';
+import { useEffect, useState } from 'react';
 import { useForm } from 'react-hook-form';
 import { zodResolver } from '@hookform/resolvers/zod';
 import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
@@ -34,16 +34,42 @@ import { listFms } from '../../lib/api/fms.js';
 import { listParts } from '../../lib/api/parts.js';
 import { ApiRequestError } from '../../lib/api/client.js';
 import { queryKeys } from '../../lib/queryKeys.js';
-import type { Repair } from '../../lib/api/types.js';
+import type { PartModel, Repair } from '../../lib/api/types.js';
+import { PartModelCombobox } from '../common/PartModelCombobox.js';
 
-const Schema = z.object({
-  hostId: z.string().uuid('Pick a host'),
-  brokenSerial: z.string().trim().min(1, 'Required').max(128),
-  brokenMpn: z.string().trim().min(1, 'Required').max(128),
-  brokenManufacturerId: z.string().uuid('Select a manufacturer'),
-  replacementSerial: z.string().trim().min(1, 'Required').max(128),
-  fmId: z.string().optional(),
-});
+// When the broken serial matches an existing Part the model fields are skipped entirely;
+// otherwise the tech either picks an existing PartModel (partModelId) or types a new MPN
+// and a manufacturer. The refine mirrors LogRepairRequest.superRefine on the server.
+const Schema = z
+  .object({
+    hostId: z.string().uuid('Pick a host'),
+    brokenSerial: z.string().trim().min(1, 'Required').max(128),
+    brokenPartModelId: z.string().uuid().optional(),
+    brokenMpn: z.string().trim().max(128).optional(),
+    brokenManufacturerId: z.string().uuid().optional(),
+    replacementSerial: z.string().trim().min(1, 'Required').max(128),
+    fmId: z.string().optional(),
+    brokenExists: z.boolean().optional(),
+  })
+  .superRefine((v, ctx) => {
+    if (v.brokenExists) return;
+    const hasModel = Boolean(v.brokenPartModelId);
+    const hasNew = Boolean(v.brokenMpn && v.brokenMpn.length > 0);
+    if (!hasModel && !hasNew) {
+      ctx.addIssue({
+        code: z.ZodIssueCode.custom,
+        message: 'Pick a part model or enter a new MPN',
+        path: ['brokenPartModelId'],
+      });
+    }
+    if (hasNew && !v.brokenManufacturerId) {
+      ctx.addIssue({
+        code: z.ZodIssueCode.custom,
+        message: 'Select a manufacturer for the new model',
+        path: ['brokenManufacturerId'],
+      });
+    }
+  });
 type Values = z.infer<typeof Schema>;
 
 const NO_FM = '__none__';
@@ -57,27 +83,34 @@ interface LogRepairDialogProps {
 export function LogRepairDialog({ open, onOpenChange, onLogged }: LogRepairDialogProps) {
   const queryClient = useQueryClient();
 
+  const [pickedModel, setPickedModel] = useState<PartModel | null>(null);
+
   const form = useForm<Values>({
     resolver: zodResolver(Schema),
     defaultValues: {
       hostId: '',
       brokenSerial: '',
+      brokenPartModelId: '',
       brokenMpn: '',
       brokenManufacturerId: '',
       replacementSerial: '',
       fmId: '',
+      brokenExists: false,
     },
   });
 
   useEffect(() => {
     if (!open) return;
+    setPickedModel(null);
     form.reset({
       hostId: '',
       brokenSerial: '',
+      brokenPartModelId: '',
       brokenMpn: '',
       brokenManufacturerId: '',
       replacementSerial: '',
       fmId: '',
+      brokenExists: false,
     });
   }, [open, form]);
 
@@ -115,16 +148,30 @@ export function LogRepairDialog({ open, onOpenChange, onLogged }: LogRepairDialo
     (p) => p.serialNumber === brokenSerial,
   );
 
+  // Keep a form-level flag so the zod refine can skip model validation when the broken part
+  // is already in the catalog (server just reuses the existing PartModel).
+  useEffect(() => {
+    form.setValue('brokenExists', Boolean(existingBroken), { shouldValidate: true });
+  }, [existingBroken, form]);
+
   const mutation = useMutation({
-    mutationFn: (v: Values) =>
-      logRepair({
+    mutationFn: (v: Values) => {
+      const base = {
         hostId: v.hostId,
         brokenSerial: v.brokenSerial.trim(),
-        brokenMpn: v.brokenMpn.trim(),
-        brokenManufacturerId: v.brokenManufacturerId,
         replacementSerial: v.replacementSerial.trim(),
         fmId: v.fmId ? v.fmId : undefined,
-      }),
+      };
+      // If the broken part is already catalogued, the server ignores model fields entirely.
+      if (existingBroken) return logRepair(base);
+      const modelPayload = v.brokenPartModelId
+        ? { brokenPartModelId: v.brokenPartModelId }
+        : {
+            brokenMpn: v.brokenMpn?.trim(),
+            brokenManufacturerId: v.brokenManufacturerId,
+          };
+      return logRepair({ ...base, ...modelPayload });
+    },
     onSuccess: (repair) => {
       toast.success('Repair logged');
       queryClient.invalidateQueries({ queryKey: queryKeys.repairs.all });
@@ -217,45 +264,68 @@ export function LogRepairDialog({ open, onOpenChange, onLogged }: LogRepairDialo
               />
             </div>
 
-            <div className="grid grid-cols-2 gap-3">
-              <FormField
-                control={form.control}
-                name="brokenMpn"
-                render={({ field }) => (
-                  <FormItem>
-                    <FormLabel>Broken MPN</FormLabel>
-                    <FormControl>
-                      <Input {...field} />
-                    </FormControl>
-                    <FormMessage />
-                  </FormItem>
+            {!existingBroken && (
+              <>
+                <FormField
+                  control={form.control}
+                  name="brokenPartModelId"
+                  render={() => (
+                    <FormItem>
+                      <FormLabel>Broken part model</FormLabel>
+                      <PartModelCombobox
+                        value={pickedModel}
+                        newMpn={form.watch('brokenMpn') || null}
+                        onPick={(m) => {
+                          setPickedModel(m);
+                          form.setValue('brokenPartModelId', m.id, { shouldValidate: true });
+                          form.setValue('brokenMpn', '');
+                          form.setValue('brokenManufacturerId', '');
+                        }}
+                        onCreateNew={(mpn) => {
+                          setPickedModel(null);
+                          form.setValue('brokenPartModelId', '');
+                          form.setValue('brokenMpn', mpn, { shouldValidate: true });
+                        }}
+                        onClear={() => {
+                          setPickedModel(null);
+                          form.setValue('brokenPartModelId', '');
+                          form.setValue('brokenMpn', '');
+                          form.setValue('brokenManufacturerId', '');
+                        }}
+                      />
+                      <FormMessage />
+                    </FormItem>
+                  )}
+                />
+
+                {!pickedModel && form.watch('brokenMpn') && (
+                  <FormField
+                    control={form.control}
+                    name="brokenManufacturerId"
+                    render={({ field }) => (
+                      <FormItem>
+                        <FormLabel>Manufacturer (for new model)</FormLabel>
+                        <Select value={field.value ?? ''} onValueChange={field.onChange}>
+                          <FormControl>
+                            <SelectTrigger>
+                              <SelectValue placeholder="Select" />
+                            </SelectTrigger>
+                          </FormControl>
+                          <SelectContent>
+                            {manufacturers.data?.data.map((m) => (
+                              <SelectItem key={m.id} value={m.id}>
+                                {m.name}
+                              </SelectItem>
+                            ))}
+                          </SelectContent>
+                        </Select>
+                        <FormMessage />
+                      </FormItem>
+                    )}
+                  />
                 )}
-              />
-              <FormField
-                control={form.control}
-                name="brokenManufacturerId"
-                render={({ field }) => (
-                  <FormItem>
-                    <FormLabel>Broken manufacturer</FormLabel>
-                    <Select value={field.value} onValueChange={field.onChange}>
-                      <FormControl>
-                        <SelectTrigger>
-                          <SelectValue placeholder="Select" />
-                        </SelectTrigger>
-                      </FormControl>
-                      <SelectContent>
-                        {manufacturers.data?.data.map((m) => (
-                          <SelectItem key={m.id} value={m.id}>
-                            {m.name}
-                          </SelectItem>
-                        ))}
-                      </SelectContent>
-                    </Select>
-                    <FormMessage />
-                  </FormItem>
-                )}
-              />
-            </div>
+              </>
+            )}
 
             <FormField
               control={form.control}
diff --git a/apps/web/src/lib/api/custody.ts b/apps/web/src/lib/api/custody.ts
index 3183ad0..ab8c4aa 100644
--- a/apps/web/src/lib/api/custody.ts
+++ b/apps/web/src/lib/api/custody.ts
@@ -11,3 +11,8 @@ export async function dropOff(partId: string, input: DropOffRequest): Promise<Pa
   const res = await api.post<Part>(`/custody/${partId}/drop-off`, input);
   return res.data;
 }
+
+export async function takeForRepair(partId: string): Promise<Part> {
+  const res = await api.post<Part>(`/custody/${partId}/take-for-repair`);
+  return res.data;
+}
diff --git a/apps/web/src/lib/api/hosts.ts b/apps/web/src/lib/api/hosts.ts
index 3e8e71a..7949311 100644
--- a/apps/web/src/lib/api/hosts.ts
+++ b/apps/web/src/lib/api/hosts.ts
@@ -7,6 +7,8 @@ export type HostListFilters = {
   page?: number;
   pageSize?: number;
   q?: string;
+  state?: string;
+  stack?: string;
 };
 
 export function listHosts(filters: HostListFilters = {}) {
diff --git a/apps/web/src/lib/api/part-models.ts b/apps/web/src/lib/api/part-models.ts
index b97617a..033d349 100644
--- a/apps/web/src/lib/api/part-models.ts
+++ b/apps/web/src/lib/api/part-models.ts
@@ -10,6 +10,7 @@ export type PartModelListFilters = {
   page?: number;
   pageSize?: number;
   manufacturerId?: string;
+  categoryId?: string;
   q?: string;
   eolBefore?: string;
 };
diff --git a/apps/web/src/lib/api/types.ts b/apps/web/src/lib/api/types.ts
index 8899ac9..2d00adc 100644
--- a/apps/web/src/lib/api/types.ts
+++ b/apps/web/src/lib/api/types.ts
@@ -1,4 +1,11 @@
-import type { FmStatus, PartEventType, PartState, Role } from '@vector/shared';
+import type {
+  FmStatus,
+  HostState,
+  HostStack,
+  PartEventType,
+  PartState,
+  Role,
+} from '@vector/shared';
 
 // Shapes mirror Prisma rows the API returns (dates serialized as ISO strings).
 // Keep these in sync with apps/api/src/services responses.
@@ -14,12 +21,14 @@ export interface PartModel {
   id: string;
   manufacturerId: string;
   mpn: string;
+  categoryId: string | null;
   eolDate: string | null;
   destroyOnFail: boolean;
   notes: string | null;
   createdAt: string;
   updatedAt: string;
   manufacturer?: Manufacturer;
+  category?: Category | null;
   _count?: { parts: number };
 }
 
@@ -59,7 +68,6 @@ export interface Part {
   price: number | null;
   state: PartState;
   binId: string | null;
-  categoryId: string | null;
   hostId: string | null;
   custodianId: string | null;
   notes: string | null;
@@ -99,6 +107,8 @@ export interface Host {
   name: string;
   location: string | null;
   notes: string | null;
+  state: HostState;
+  stack: HostStack;
   createdAt: string;
   updatedAt: string;
 }
diff --git a/apps/web/src/pages/Dashboard.tsx b/apps/web/src/pages/Dashboard.tsx
index e7478f0..da7819c 100644
--- a/apps/web/src/pages/Dashboard.tsx
+++ b/apps/web/src/pages/Dashboard.tsx
@@ -35,6 +35,7 @@ const STATE_LABELS: Record<PartState, string> = {
   PENDING_DESTRUCTION: 'Pending destruction',
   PENDING_DROP_IN_CUSTODY: 'In custody',
   PENDING_DESTRUCTION_IN_CUSTODY: 'In custody (destroy)',
+  PENDING_REPAIR: 'Held for repair',
 };
 
 const STATE_COLORS: Record<PartState, string> = {
@@ -44,10 +45,11 @@ const STATE_COLORS: Record<PartState, string> = {
   PENDING_DESTRUCTION: 'hsl(38 92% 50%)',
   PENDING_DROP_IN_CUSTODY: 'hsl(262 83% 58%)',
   PENDING_DESTRUCTION_IN_CUSTODY: 'hsl(340 82% 52%)',
+  PENDING_REPAIR: 'hsl(197 80% 50%)',
 };
 
-function currency(cents: number): string {
-  return (cents / 100).toLocaleString(undefined, { style: 'currency', currency: 'USD' });
+function currency(dollars: number): string {
+  return dollars.toLocaleString(undefined, { style: 'currency', currency: 'USD' });
 }
 
 export default function Dashboard() {
@@ -159,7 +161,7 @@ export default function Dashboard() {
                         .map((s) => ({
                           name: STATE_LABELS[s.state],
                           state: s.state,
-                          value: s.totalPrice / 100,
+                          value: s.totalPrice,
                         }))}
                       dataKey="value"
                       nameKey="name"
diff --git a/apps/web/src/pages/Hosts.tsx b/apps/web/src/pages/Hosts.tsx
index 5da5f00..a2cf965 100644
--- a/apps/web/src/pages/Hosts.tsx
+++ b/apps/web/src/pages/Hosts.tsx
@@ -4,6 +4,7 @@ import { useMutation, useQueryClient } from '@tanstack/react-query';
 import { Edit, MoreHorizontal, Plus, Server, Trash2 } from 'lucide-react';
 import { toast } from 'sonner';
 import {
+  Badge,
   Button,
   DropdownMenu,
   DropdownMenuContent,
@@ -55,6 +56,25 @@ export default function Hosts() {
         header: 'Name',
         cell: ({ row }) => <span className="font-medium">{row.original.name}</span>,
       },
+      {
+        accessorKey: 'state',
+        header: 'State',
+        cell: ({ row }) => {
+          const s = row.original.state;
+          const variant =
+            s === 'DEPLOYED' ? 'secondary' : s === 'DEGRADED' ? 'destructive' : 'outline';
+          return <Badge variant={variant}>{s}</Badge>;
+        },
+      },
+      {
+        accessorKey: 'stack',
+        header: 'Stack',
+        cell: ({ row }) => (
+          <Badge variant="outline" className="text-xs">
+            {row.original.stack}
+          </Badge>
+        ),
+      },
       {
         accessorKey: 'location',
         header: 'Location',
diff --git a/apps/web/src/pages/Locations.tsx b/apps/web/src/pages/Locations.tsx
index fb57aaf..cea33be 100644
--- a/apps/web/src/pages/Locations.tsx
+++ b/apps/web/src/pages/Locations.tsx
@@ -1,8 +1,13 @@
+import { useMemo } from 'react';
+import { useQuery } from '@tanstack/react-query';
 import { parseAsString, useQueryState } from 'nuqs';
+import { ChevronRight, MapPin } from 'lucide-react';
 import { PageHeader } from '../components/layout/PageHeader.js';
-import { SiteList } from '../components/locations/SiteList.js';
-import { RoomDrawer } from '../components/locations/RoomDrawer.js';
+import { SiteRoomTree } from '../components/locations/SiteRoomTree.js';
 import { BinGrid } from '../components/locations/BinGrid.js';
+import { listSites } from '../lib/api/sites.js';
+import { listRooms } from '../lib/api/rooms.js';
+import { queryKeys } from '../lib/queryKeys.js';
 import { useAuth } from '../contexts/AuthContext.js';
 
 export default function Locations() {
@@ -20,23 +25,94 @@ export default function Locations() {
     void setRoomId(id || null);
   };
 
+  const sites = useQuery({
+    queryKey: queryKeys.sites.list({ pageSize: 100 }),
+    queryFn: () => listSites({ pageSize: 100 }),
+  });
+  const rooms = useQuery({
+    queryKey: queryKeys.rooms.list({ siteId, pageSize: 100 }),
+    queryFn: () => listRooms({ siteId: siteId!, pageSize: 100 }),
+    enabled: Boolean(siteId),
+  });
+
+  const siteName = useMemo(
+    () => sites.data?.data.find((s) => s.id === siteId)?.name,
+    [sites.data, siteId],
+  );
+  const roomName = useMemo(
+    () => rooms.data?.data.find((r) => r.id === roomId)?.name,
+    [rooms.data, roomId],
+  );
+
   return (
     <div className="flex h-[calc(100vh-var(--spacing-topbar,3.25rem)-3rem)] flex-col gap-4">
       <PageHeader
         title="Locations"
-        description="Sites → Rooms → Bins. Select a site to drill in."
+        description="Sites → Rooms → Bins. Pick a room to see its bins."
       />
-      <div className="grid min-h-0 flex-1 grid-cols-[16rem_16rem_1fr] overflow-hidden rounded-lg border border-border bg-card">
+      <div className="grid min-h-0 flex-1 grid-cols-[18rem_1fr] overflow-hidden rounded-lg border border-border bg-card">
         <div className="border-r border-border">
-          <SiteList selectedId={siteId} onSelect={handleSite} canEdit={canEdit} />
+          <SiteRoomTree
+            siteId={siteId}
+            roomId={roomId}
+            onSelectSite={handleSite}
+            onSelectRoom={handleRoom}
+            canEdit={canEdit}
+          />
         </div>
-        <div className="border-r border-border">
-          <RoomDrawer siteId={siteId} selectedId={roomId} onSelect={handleRoom} canEdit={canEdit} />
-        </div>
-        <div>
-          <BinGrid roomId={roomId} canEdit={canEdit} />
+        <div className="flex min-h-0 flex-col">
+          <Breadcrumb siteName={siteName} roomName={roomName} />
+          <div className="min-h-0 flex-1 overflow-y-auto">
+            {roomId ? (
+              <BinGrid roomId={roomId} canEdit={canEdit} />
+            ) : (
+              <EmptyPane siteSelected={Boolean(siteId)} />
+            )}
+          </div>
         </div>
       </div>
     </div>
   );
 }
+
+function Breadcrumb({
+  siteName,
+  roomName,
+}: {
+  siteName: string | undefined;
+  roomName: string | undefined;
+}) {
+  return (
+    <div className="flex items-center gap-1.5 border-b border-border px-4 py-2 text-sm text-muted-foreground">
+      {siteName ? (
+        <>
+          <span className="text-foreground">{siteName}</span>
+          {roomName && (
+            <>
+              <ChevronRight className="h-3.5 w-3.5 opacity-60" />
+              <span className="text-foreground">{roomName}</span>
+            </>
+          )}
+        </>
+      ) : (
+        <span>Select a site to begin.</span>
+      )}
+    </div>
+  );
+}
+
+function EmptyPane({ siteSelected }: { siteSelected: boolean }) {
+  return (
+    <div className="flex h-full items-center justify-center p-8">
+      <div className="flex max-w-sm flex-col items-center gap-2 rounded-lg border border-dashed border-border bg-muted/30 px-8 py-10 text-center">
+        <MapPin className="h-6 w-6 text-muted-foreground" />
+        <p className="text-sm font-medium">
+          {siteSelected ? 'Pick a room' : 'Pick a site and room'}
+        </p>
+        <p className="text-xs text-muted-foreground">
+          Bins live inside rooms. Expand a site in the tree and choose a room to manage its bins.
+        </p>
+      </div>
+    </div>
+  );
+}
diff --git a/apps/web/src/pages/MyCustody.tsx b/apps/web/src/pages/MyCustody.tsx
index 15203b7..ec67096 100644
--- a/apps/web/src/pages/MyCustody.tsx
+++ b/apps/web/src/pages/MyCustody.tsx
@@ -2,7 +2,7 @@ import { useMemo, useState } from 'react';
 import { Link } from 'react-router-dom';
 import type { ColumnDef } from '@tanstack/react-table';
 import { useMutation, useQueryClient } from '@tanstack/react-query';
-import { Hand, PackageCheck } from 'lucide-react';
+import { Hand, PackageCheck, Undo2 } from 'lucide-react';
 import { toast } from 'sonner';
 import { Button } from '@vector/ui';
 import { PageHeader } from '../components/layout/PageHeader.js';
@@ -74,13 +74,24 @@ export default function MyCustody() {
       {
         id: 'actions',
         header: () => <span className="sr-only">Actions</span>,
-        size: 140,
-        cell: ({ row }) => (
-          <Button size="sm" variant="outline" onClick={() => setDropping(row.original)}>
-            <PackageCheck className="h-3.5 w-3.5" />
-            Drop in bin
-          </Button>
-        ),
+        size: 160,
+        cell: ({ row }) => {
+          const pending = row.original.state === 'PENDING_REPAIR';
+          return (
+            <Button
+              size="sm"
+              variant="outline"
+              onClick={() => setDropping(row.original)}
+            >
+              {pending ? (
+                <Undo2 className="h-3.5 w-3.5" />
+              ) : (
+                <PackageCheck className="h-3.5 w-3.5" />
+              )}
+              {pending ? 'Return to bin' : 'Drop in bin'}
+            </Button>
+          );
+        },
       },
     ],
     [],
diff --git a/apps/web/src/pages/PartModels.tsx b/apps/web/src/pages/PartModels.tsx
index e48ebd1..cd52fad 100644
--- a/apps/web/src/pages/PartModels.tsx
+++ b/apps/web/src/pages/PartModels.tsx
@@ -58,6 +58,16 @@ export default function PartModels() {
           <span className="font-mono text-xs font-medium">{row.original.mpn}</span>
         ),
       },
+      {
+        id: 'category',
+        header: 'Category',
+        cell: ({ row }) =>
+          row.original.category ? (
+            <Badge variant="outline">{row.original.category.name}</Badge>
+          ) : (
+            <span className="text-xs text-muted-foreground">—</span>
+          ),
+      },
       {
         accessorKey: 'eolDate',
         header: 'EOL',
@@ -87,7 +97,7 @@ export default function PartModels() {
           row.original.destroyOnFail ? (
             <Check className="h-4 w-4 text-foreground" />
           ) : (
-            <span className="text-xs text-muted-foreground">—</span>
+            <span className="text-xs text-muted-foreground">No</span>
           ),
       },
       {
diff --git a/apps/web/src/pages/Parts.tsx b/apps/web/src/pages/Parts.tsx
index 40b3331..fcb7886 100644
--- a/apps/web/src/pages/Parts.tsx
+++ b/apps/web/src/pages/Parts.tsx
@@ -4,7 +4,7 @@ import type { ColumnDef } from '@tanstack/react-table';
 import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
 import { parseAsString } from 'nuqs';
 import { toast } from 'sonner';
-import { Edit, MoreHorizontal, Package, Plus, Trash2 } from 'lucide-react';
+import { Edit, HandHelping, MoreHorizontal, Package, Plus, Trash2 } from 'lucide-react';
 import {
   Button,
   DropdownMenu,
@@ -26,7 +26,9 @@ import { PartBulkStateDialog } from '../components/parts/PartBulkStateDialog.js'
 import { ConfirmDialog } from '../components/ConfirmDialog.js';
 import { listParts, deletePart } from '../lib/api/parts.js';
 import { listManufacturers } from '../lib/api/manufacturers.js';
+import { listCategories } from '../lib/api/categories.js';
 import { listTags } from '../lib/api/tags.js';
+import { takeForRepair } from '../lib/api/custody.js';
 import { ApiRequestError } from '../lib/api/client.js';
 import type { Part } from '../lib/api/types.js';
 import { queryKeys } from '../lib/queryKeys.js';
@@ -35,12 +37,14 @@ import { useAuth } from '../contexts/AuthContext.js';
 type PartsFilters = {
   state: string | null;
   manufacturerId: string | null;
+  categoryId: string | null;
   tagId: string | null;
 };
 
 const filterParsers = {
   state: parseAsString,
   manufacturerId: parseAsString,
+  categoryId: parseAsString,
   tagId: parseAsString,
 };
 
@@ -62,6 +66,10 @@ export default function Parts() {
     queryKey: queryKeys.manufacturers.list({ pageSize: 100 }),
     queryFn: () => listManufacturers({ pageSize: 100 }),
   });
+  const categoriesQuery = useQuery({
+    queryKey: queryKeys.categories.list({ pageSize: 100 }),
+    queryFn: () => listCategories({ pageSize: 100 }),
+  });
   const tagsQuery = useQuery({
     queryKey: queryKeys.tags.list({ pageSize: 100 }),
     queryFn: () => listTags({ pageSize: 100 }),
@@ -79,6 +87,17 @@ export default function Parts() {
     },
   });
 
+  const takeForRepairMutation = useMutation({
+    mutationFn: (id: string) => takeForRepair(id),
+    onSuccess: () => {
+      toast.success('Part moved into your custody');
+      queryClient.invalidateQueries({ queryKey: queryKeys.parts.all });
+      queryClient.invalidateQueries({ queryKey: queryKeys.custody.all });
+    },
+    onError: (err) =>
+      toast.error(err instanceof ApiRequestError ? err.body.message : 'Could not take part'),
+  });
+
   const columns = useMemo<ColumnDef<Part>[]>(
     () => [
       {
@@ -107,6 +126,18 @@ export default function Parts() {
           <span className="text-sm text-muted-foreground">{row.original.manufacturer.name}</span>
         ),
       },
+      {
+        id: 'category',
+        header: 'Category',
+        cell: ({ row }) =>
+          row.original.partModel.category ? (
+            <span className="text-xs text-muted-foreground">
+              {row.original.partModel.category.name}
+            </span>
+          ) : (
+            <span className="text-xs text-muted-foreground">—</span>
+          ),
+      },
       {
         accessorKey: 'state',
         header: 'State',
@@ -159,7 +190,7 @@ export default function Parts() {
                 <MoreHorizontal className="h-4 w-4" />
               </Button>
             </DropdownMenuTrigger>
-            <DropdownMenuContent align="end" className="w-40">
+            <DropdownMenuContent align="end" className="w-44">
               <DropdownMenuItem onSelect={() => navigate(`/parts/${row.original.id}`)}>
                 View
               </DropdownMenuItem>
@@ -167,6 +198,15 @@ export default function Parts() {
                 <Edit className="h-3.5 w-3.5" />
                 Edit
               </DropdownMenuItem>
+              {row.original.state === 'SPARE' && (
+                <DropdownMenuItem
+                  onSelect={() => takeForRepairMutation.mutate(row.original.id)}
+                  disabled={takeForRepairMutation.isPending}
+                >
+                  <HandHelping className="h-3.5 w-3.5" />
+                  Take into custody
+                </DropdownMenuItem>
+              )}
               {isAdmin && (
                 <>
                   <DropdownMenuSeparator />
@@ -184,7 +224,7 @@ export default function Parts() {
         ),
       },
     ],
-    [navigate, isAdmin],
+    [navigate, isAdmin, takeForRepairMutation],
   );
 
   return (
@@ -213,6 +253,7 @@ export default function Parts() {
             sort: params.sort,
             state: params.filters.state,
             manufacturerId: params.filters.manufacturerId,
+            categoryId: params.filters.categoryId,
             tagId: params.filters.tagId,
           })
         }
@@ -224,6 +265,7 @@ export default function Parts() {
             sort: params.sort,
             state: params.filters.state ?? undefined,
             manufacturerId: params.filters.manufacturerId ?? undefined,
+            categoryId: params.filters.categoryId ?? undefined,
             tagId: params.filters.tagId ?? undefined,
           })
         }
@@ -239,12 +281,15 @@ export default function Parts() {
         toolbar={({ filters, setFilter }) => (
           <PartsFilters
             manufacturers={manufacturers.data?.data ?? []}
+            categories={categoriesQuery.data?.data ?? []}
             tags={tagsQuery.data?.data ?? []}
             state={filters.state ?? ALL}
             manufacturerId={filters.manufacturerId ?? ALL}
+            categoryId={filters.categoryId ?? ALL}
             tagId={filters.tagId ?? ALL}
             onState={(v) => setFilter('state', v === ALL ? null : v)}
             onManufacturer={(v) => setFilter('manufacturerId', v === ALL ? null : v)}
+            onCategory={(v) => setFilter('categoryId', v === ALL ? null : v)}
             onTag={(v) => setFilter('tagId', v === ALL ? null : v)}
           />
         )}
@@ -296,23 +341,29 @@ export default function Parts() {
 
 interface PartsFiltersProps {
   manufacturers: { id: string; name: string }[];
+  categories: { id: string; name: string }[];
   tags: { id: string; name: string }[];
   state: string;
   manufacturerId: string;
+  categoryId: string;
   tagId: string;
   onState: (v: string) => void;
   onManufacturer: (v: string) => void;
+  onCategory: (v: string) => void;
   onTag: (v: string) => void;
 }
 
 function PartsFilters({
   manufacturers,
+  categories,
   tags,
   state,
   manufacturerId,
+  categoryId,
   tagId,
   onState,
   onManufacturer,
+  onCategory,
   onTag,
 }: PartsFiltersProps) {
   return (
@@ -343,6 +394,19 @@ function PartsFilters({
           ))}
         </SelectContent>
       </Select>
+      <Select value={categoryId} onValueChange={onCategory}>
+        <SelectTrigger className="h-8 w-40 text-xs">
+          <SelectValue placeholder="Category" />
+        </SelectTrigger>
+        <SelectContent>
+          <SelectItem value={ALL}>All categories</SelectItem>
+          {categories.map((c) => (
+            <SelectItem key={c.id} value={c.id}>
+              {c.name}
+            </SelectItem>
+          ))}
+        </SelectContent>
+      </Select>
       <Select value={tagId} onValueChange={onTag}>
         <SelectTrigger className="h-8 w-36 text-xs">
           <SelectValue placeholder="Tag" />
diff --git a/packages/db/prisma/migrations/20260417171222_laundry_list_pass/migration.sql b/packages/db/prisma/migrations/20260417171222_laundry_list_pass/migration.sql
new file mode 100644
index 0000000..bf7a3a1
--- /dev/null
+++ b/packages/db/prisma/migrations/20260417171222_laundry_list_pass/migration.sql
@@ -0,0 +1,78 @@
+/*
+  Warnings:
+
+  - You are about to drop the column `categoryId` on the `Part` table. All the data in the column will be lost.
+
+*/
+-- RedefineTables
+PRAGMA defer_foreign_keys=ON;
+PRAGMA foreign_keys=OFF;
+CREATE TABLE "new_Host" (
+    "id" TEXT NOT NULL PRIMARY KEY,
+    "assetId" TEXT NOT NULL,
+    "name" TEXT NOT NULL,
+    "location" TEXT,
+    "notes" TEXT,
+    "state" TEXT NOT NULL DEFAULT 'DEPLOYED',
+    "stack" TEXT NOT NULL DEFAULT 'PRODUCTION',
+    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" DATETIME NOT NULL
+);
+INSERT INTO "new_Host" ("assetId", "createdAt", "id", "location", "name", "notes", "updatedAt") SELECT "assetId", "createdAt", "id", "location", "name", "notes", "updatedAt" FROM "Host";
+DROP TABLE "Host";
+ALTER TABLE "new_Host" RENAME TO "Host";
+CREATE UNIQUE INDEX "Host_assetId_key" ON "Host"("assetId");
+CREATE UNIQUE INDEX "Host_name_key" ON "Host"("name");
+CREATE INDEX "Host_state_idx" ON "Host"("state");
+CREATE INDEX "Host_stack_idx" ON "Host"("stack");
+CREATE TABLE "new_Part" (
+    "id" TEXT NOT NULL PRIMARY KEY,
+    "serialNumber" TEXT NOT NULL,
+    "partModelId" TEXT NOT NULL,
+    "manufacturerId" TEXT NOT NULL,
+    "price" REAL,
+    "state" TEXT NOT NULL DEFAULT 'SPARE',
+    "binId" TEXT,
+    "hostId" TEXT,
+    "custodianId" TEXT,
+    "notes" TEXT,
+    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" DATETIME NOT NULL,
+    CONSTRAINT "Part_partModelId_fkey" FOREIGN KEY ("partModelId") REFERENCES "PartModel" ("id") ON DELETE RESTRICT ON UPDATE CASCADE,
+    CONSTRAINT "Part_manufacturerId_fkey" FOREIGN KEY ("manufacturerId") REFERENCES "Manufacturer" ("id") ON DELETE RESTRICT ON UPDATE CASCADE,
+    CONSTRAINT "Part_binId_fkey" FOREIGN KEY ("binId") REFERENCES "Bin" ("id") ON DELETE SET NULL ON UPDATE CASCADE,
+    CONSTRAINT "Part_hostId_fkey" FOREIGN KEY ("hostId") REFERENCES "Host" ("id") ON DELETE SET NULL ON UPDATE CASCADE,
+    CONSTRAINT "Part_custodianId_fkey" FOREIGN KEY ("custodianId") REFERENCES "User" ("id") ON DELETE SET NULL ON UPDATE CASCADE
+);
+INSERT INTO "new_Part" ("binId", "createdAt", "custodianId", "hostId", "id", "manufacturerId", "notes", "partModelId", "price", "serialNumber", "state", "updatedAt") SELECT "binId", "createdAt", "custodianId", "hostId", "id", "manufacturerId", "notes", "partModelId", "price", "serialNumber", "state", "updatedAt" FROM "Part";
+DROP TABLE "Part";
+ALTER TABLE "new_Part" RENAME TO "Part";
+CREATE UNIQUE INDEX "Part_serialNumber_key" ON "Part"("serialNumber");
+CREATE INDEX "Part_state_idx" ON "Part"("state");
+CREATE INDEX "Part_binId_idx" ON "Part"("binId");
+CREATE INDEX "Part_manufacturerId_idx" ON "Part"("manufacturerId");
+CREATE INDEX "Part_partModelId_idx" ON "Part"("partModelId");
+CREATE INDEX "Part_hostId_idx" ON "Part"("hostId");
+CREATE INDEX "Part_custodianId_idx" ON "Part"("custodianId");
+CREATE TABLE "new_PartModel" (
+    "id" TEXT NOT NULL PRIMARY KEY,
+    "manufacturerId" TEXT NOT NULL,
+    "mpn" TEXT NOT NULL,
+    "eolDate" DATETIME,
+    "destroyOnFail" BOOLEAN NOT NULL DEFAULT false,
+    "notes" TEXT,
+    "categoryId" TEXT,
+    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" DATETIME NOT NULL,
+    CONSTRAINT "PartModel_manufacturerId_fkey" FOREIGN KEY ("manufacturerId") REFERENCES "Manufacturer" ("id") ON DELETE RESTRICT ON UPDATE CASCADE,
+    CONSTRAINT "PartModel_categoryId_fkey" FOREIGN KEY ("categoryId") REFERENCES "Category" ("id") ON DELETE SET NULL ON UPDATE CASCADE
+);
+INSERT INTO "new_PartModel" ("createdAt", "destroyOnFail", "eolDate", "id", "manufacturerId", "mpn", "notes", "updatedAt") SELECT "createdAt", "destroyOnFail", "eolDate", "id", "manufacturerId", "mpn", "notes", "updatedAt" FROM "PartModel";
+DROP TABLE "PartModel";
+ALTER TABLE "new_PartModel" RENAME TO "PartModel";
+CREATE INDEX "PartModel_manufacturerId_idx" ON "PartModel"("manufacturerId");
+CREATE INDEX "PartModel_eolDate_idx" ON "PartModel"("eolDate");
+CREATE INDEX "PartModel_categoryId_idx" ON "PartModel"("categoryId");
+CREATE UNIQUE INDEX "PartModel_manufacturerId_mpn_key" ON "PartModel"("manufacturerId", "mpn");
+PRAGMA foreign_keys=ON;
+PRAGMA defer_foreign_keys=OFF;
diff --git a/packages/db/prisma/schema.prisma b/packages/db/prisma/schema.prisma
index ad426fc..2f3bfbd 100644
--- a/packages/db/prisma/schema.prisma
+++ b/packages/db/prisma/schema.prisma
@@ -62,6 +62,8 @@ model PartModel {
   eolDate        DateTime?
   destroyOnFail  Boolean      @default(false)
   notes          String?
+  categoryId     String?
+  category       Category?    @relation(fields: [categoryId], references: [id], onDelete: SetNull)
   createdAt      DateTime     @default(now())
   updatedAt      DateTime     @updatedAt
   parts          Part[]
@@ -69,6 +71,7 @@ model PartModel {
   @@unique([manufacturerId, mpn])
   @@index([manufacturerId])
   @@index([eolDate])
+  @@index([categoryId])
 }
 
 model Site {
@@ -106,12 +109,12 @@ model Bin {
 }
 
 model Category {
-  id          String   @id @default(uuid())
-  name        String   @unique
+  id          String      @id @default(uuid())
+  name        String      @unique
   description String?
-  createdAt   DateTime @default(now())
-  updatedAt   DateTime @updatedAt
-  parts       Part[]
+  createdAt   DateTime    @default(now())
+  updatedAt   DateTime    @updatedAt
+  partModels  PartModel[]
 }
 
 model Part {
@@ -125,8 +128,6 @@ model Part {
   state              String       @default("SPARE")
   binId              String?
   bin                Bin?         @relation(fields: [binId], references: [id], onDelete: SetNull)
-  categoryId         String?
-  category           Category?    @relation(fields: [categoryId], references: [id], onDelete: SetNull)
   hostId             String?
   host               Host?        @relation(fields: [hostId], references: [id], onDelete: SetNull)
   custodianId        String?
@@ -144,7 +145,6 @@ model Part {
   @@index([binId])
   @@index([manufacturerId])
   @@index([partModelId])
-  @@index([categoryId])
   @@index([hostId])
   @@index([custodianId])
 }
@@ -191,11 +191,16 @@ model Host {
   name      String   @unique
   location  String?
   notes     String?
+  state     String   @default("DEPLOYED")
+  stack     String   @default("PRODUCTION")
   createdAt DateTime @default(now())
   updatedAt DateTime @updatedAt
   parts     Part[]
   fms       Fm[]
   repairs   Repair[]
+
+  @@index([state])
+  @@index([stack])
 }
 
 model Fm {
diff --git a/packages/db/prisma/seed.ts b/packages/db/prisma/seed.ts
index 476b059..e3fd5bd 100644
--- a/packages/db/prisma/seed.ts
+++ b/packages/db/prisma/seed.ts
@@ -17,6 +17,16 @@ async function main() {
 
   console.log(`Seeded admin user: ${admin.username} (${admin.email})`);
   console.log('Default password: admin — change this immediately!');
+
+  const categoryNames = ['GPU', 'RAM', 'SSD', 'HDD', 'NIC', 'CPU', 'PSU', 'MOBO'];
+  for (const name of categoryNames) {
+    await prisma.category.upsert({
+      where: { name },
+      update: {},
+      create: { name },
+    });
+  }
+  console.log(`Seeded ${categoryNames.length} part categories.`);
 }
 
 main()
diff --git a/packages/shared/src/enums.ts b/packages/shared/src/enums.ts
index e73dea8..0de753a 100644
--- a/packages/shared/src/enums.ts
+++ b/packages/shared/src/enums.ts
@@ -7,9 +7,16 @@ export const PartState = z.enum([
   'PENDING_DESTRUCTION',
   'PENDING_DROP_IN_CUSTODY',
   'PENDING_DESTRUCTION_IN_CUSTODY',
+  'PENDING_REPAIR',
 ]);
 export type PartState = z.infer<typeof PartState>;
 
+export const HostState = z.enum(['DEPLOYED', 'DEGRADED', 'TESTING']);
+export type HostState = z.infer<typeof HostState>;
+
+export const HostStack = z.enum(['PRODUCTION', 'VETTING']);
+export type HostStack = z.infer<typeof HostStack>;
+
 export const Role = z.enum(['ADMIN', 'TECHNICIAN']);
 export type Role = z.infer<typeof Role>;
 
diff --git a/packages/shared/src/hosts.ts b/packages/shared/src/hosts.ts
index 9fda8e2..208af06 100644
--- a/packages/shared/src/hosts.ts
+++ b/packages/shared/src/hosts.ts
@@ -1,4 +1,5 @@
 import { z } from 'zod';
+import { HostStack, HostState } from './enums.js';
 import { PaginationQuery } from './pagination.js';
 
 const AssetId = z
@@ -12,6 +13,8 @@ export const CreateHostRequest = z.object({
   name: z.string().min(1).max(128),
   location: z.string().max(256).optional().nullable(),
   notes: z.string().max(4096).optional().nullable(),
+  state: HostState.optional(),
+  stack: HostStack.optional(),
 });
 export type CreateHostRequest = z.infer<typeof CreateHostRequest>;
 
@@ -21,11 +24,15 @@ export const UpdateHostRequest = z
     name: z.string().min(1).max(128).optional(),
     location: z.string().max(256).nullable().optional(),
     notes: z.string().max(4096).nullable().optional(),
+    state: HostState.optional(),
+    stack: HostStack.optional(),
   })
   .refine((v) => Object.keys(v).length > 0, { message: 'At least one field required' });
 export type UpdateHostRequest = z.infer<typeof UpdateHostRequest>;
 
 export const HostListQuery = PaginationQuery.extend({
   q: z.string().max(128).optional(),
+  state: HostState.optional(),
+  stack: HostStack.optional(),
 });
 export type HostListQuery = z.infer<typeof HostListQuery>;
diff --git a/packages/shared/src/part-models.ts b/packages/shared/src/part-models.ts
index 76f1533..5e68543 100644
--- a/packages/shared/src/part-models.ts
+++ b/packages/shared/src/part-models.ts
@@ -9,6 +9,7 @@ export const CreatePartModelRequest = z.object({
   eolDate: IsoDate.nullable().optional(),
   destroyOnFail: z.boolean().optional(),
   notes: z.string().max(4096).nullable().optional(),
+  categoryId: z.string().uuid().nullable().optional(),
 });
 export type CreatePartModelRequest = z.infer<typeof CreatePartModelRequest>;
 
@@ -19,12 +20,14 @@ export const UpdatePartModelRequest = z
     eolDate: IsoDate.nullable().optional(),
     destroyOnFail: z.boolean().optional(),
     notes: z.string().max(4096).nullable().optional(),
+    categoryId: z.string().uuid().nullable().optional(),
   })
   .refine((v) => Object.keys(v).length > 0, { message: 'At least one field required' });
 export type UpdatePartModelRequest = z.infer<typeof UpdatePartModelRequest>;
 
 export const PartModelListQuery = PaginationQuery.extend({
   manufacturerId: z.string().uuid().optional(),
+  categoryId: z.string().uuid().optional(),
   q: z.string().max(128).optional(),
   eolBefore: IsoDate.optional(),
 });
diff --git a/packages/shared/src/parts.ts b/packages/shared/src/parts.ts
index 64f2e7a..68df829 100644
--- a/packages/shared/src/parts.ts
+++ b/packages/shared/src/parts.ts
@@ -28,6 +28,7 @@ export function allowedLocationFieldsForState(state: PartState): {
       return { hostId: 'required', binId: 'forbidden', custodianId: 'forbidden' };
     case 'PENDING_DROP_IN_CUSTODY':
     case 'PENDING_DESTRUCTION_IN_CUSTODY':
+    case 'PENDING_REPAIR':
       return { hostId: 'forbidden', binId: 'forbidden', custodianId: 'required' };
     case 'SPARE':
     case 'BROKEN':
@@ -49,7 +50,6 @@ export const CreatePartRequest = z
     hostId: z.string().uuid().optional().nullable(),
     custodianId: z.string().uuid().optional().nullable(),
     notes: z.string().max(4096).optional().nullable(),
-    categoryId: z.string().uuid().optional().nullable(),
     tagIds: z.array(z.string().uuid()).max(32).optional(),
   })
   .superRefine((v, ctx) => {
@@ -115,7 +115,6 @@ export const UpdatePartRequest = z
     hostId: z.string().uuid().nullable().optional(),
     custodianId: z.string().uuid().nullable().optional(),
     notes: z.string().max(4096).nullable().optional(),
-    categoryId: z.string().uuid().nullable().optional(),
     tagIds: z.array(z.string().uuid()).max(32).optional(),
   })
   .refine((v) => Object.keys(v).length > 0, { message: 'At least one field required' })
diff --git a/packages/shared/src/repairs.ts b/packages/shared/src/repairs.ts
index 8d24223..ef31f2c 100644
--- a/packages/shared/src/repairs.ts
+++ b/packages/shared/src/repairs.ts
@@ -8,20 +8,33 @@ export const LogRepairRequest = z
     hostId: z.string().uuid().optional(),
     assetId: z.string().trim().min(1).max(128).optional(),
     brokenSerial: z.string().trim().min(1).max(128),
-    brokenMpn: z.string().trim().min(1).max(128),
-    brokenManufacturerId: z.string().uuid(),
+    // When the broken serial isn't in Vector yet we ingest it. Provide either a known PartModel
+    // (brokenPartModelId) or the manufacturer + mpn pair to auto-create it.
+    brokenPartModelId: z.string().uuid().optional(),
+    brokenMpn: z.string().trim().min(1).max(128).optional(),
+    brokenManufacturerId: z.string().uuid().optional(),
     replacementSerial: z.string().trim().min(1).max(128),
     fmId: z.string().uuid().optional(),
   })
   .superRefine((v, ctx) => {
-    const has = [v.hostId, v.assetId].filter((x) => x !== undefined && x !== '').length;
-    if (has !== 1) {
+    const hostHas = [v.hostId, v.assetId].filter((x) => x !== undefined && x !== '').length;
+    if (hostHas !== 1) {
       ctx.addIssue({
         code: z.ZodIssueCode.custom,
         message: 'Provide exactly one of hostId or assetId',
         path: ['hostId'],
       });
     }
+    const hasModel =
+      v.brokenPartModelId !== undefined ||
+      (v.brokenMpn !== undefined && v.brokenManufacturerId !== undefined);
+    if (!hasModel) {
+      ctx.addIssue({
+        code: z.ZodIssueCode.custom,
+        message: 'Provide brokenPartModelId or both brokenMpn and brokenManufacturerId',
+        path: ['brokenPartModelId'],
+      });
+    }
   });
 export type LogRepairRequest = z.infer<typeof LogRepairRequest>;