diff --git a/app/frontend/src/components/TidyPreview.tsx b/app/frontend/src/components/TidyPreview.tsx
index a20599f..63cc9d9 100644
--- a/app/frontend/src/components/TidyPreview.tsx
+++ b/app/frontend/src/components/TidyPreview.tsx
@@ -16,7 +16,7 @@ export interface TidyBatch {
   id: string;
   action: TidyAction;
   tag: Tag | null;
-  rule: { id: string; titleContains: string } | null;
+  rule: { id: string; titleContains: string; fileType: string | null } | null;
   itemCount: number;
   remaining: number;
   createdAt: string;
diff --git a/app/frontend/src/files.tsx b/app/frontend/src/files.tsx
index 77ca8a2..a8605c9 100644
--- a/app/frontend/src/files.tsx
+++ b/app/frontend/src/files.tsx
@@ -82,3 +82,13 @@ export function FilePreview({ item }: { item: Item }) {
     <span aria-hidden="true" className="h-14 w-14 shrink-0 rounded-lg border border-line bg-surface" />
   );
 }
+
+export const fileTypeNames: Record<string, string> = {
+  image: 'Images',
+  pdf: 'PDFs',
+  document: 'Documents',
+  spreadsheet: 'Spreadsheets',
+  presentation: 'Presentations',
+  archive: 'Zip archives',
+  text: 'Text files',
+};
diff --git a/app/frontend/src/pages/TidyPage.tsx b/app/frontend/src/pages/TidyPage.tsx
index aa019c3..55ff344 100644
--- a/app/frontend/src/pages/TidyPage.tsx
+++ b/app/frontend/src/pages/TidyPage.tsx
@@ -4,7 +4,7 @@ import { EmptyState, ListSkeleton, PageHeader, Tabs, timeAgo } from '@project-gr
 import { useAuth } from '../auth';
 import { Choice, Suggestion } from '../components/TidyList';
 import { batchSummary, itemsText, TidyPreview, undoSummary, type TidyAction, type TidyBatch, type TidyRequest } from '../components/TidyPreview';
-import { fileSize } from '../files';
+import { fileSize, fileTypeNames } from '../files';
 import { useSpaces } from '../spaces';
 import { money, shortDate } from '../subscriptions';
 import { useAction } from '../useAction';
@@ -257,7 +257,7 @@ function TidyHistory() {
                 <p className="m-0 text-ink">{batchSummary(batch)}</p>
                 <p className="mono-sm mt-1 mb-0 text-faint">
                   {timeAgo(batch.createdAt)}
-                  {batch.rule && ` · by the rule “${batch.rule.titleContains}”`}
+                  {batch.rule && ` · by the rule “${batch.rule.titleContains || fileTypeNames[batch.rule.fileType ?? '']}”`}
                   {batch.undoneAt
                     ? ' · undone'
                     : batch.remaining < batch.itemCount && ` · ${itemsText(batch.itemCount - batch.remaining)} since deleted`}
diff --git a/app/frontend/src/pages/spaces/TidyRules.tsx b/app/frontend/src/pages/spaces/TidyRules.tsx
index 885259c..d9d17a6 100644
--- a/app/frontend/src/pages/spaces/TidyRules.tsx
+++ b/app/frontend/src/pages/spaces/TidyRules.tsx
@@ -2,6 +2,7 @@ import { useState } from 'react';
 import { ConfirmDialog, ListSkeleton, TagChip, TextField } from '@project-graphite/ui';
 import { useAuth } from '../../auth';
 import { batchSummary, TidyPreview, type TidyRequest } from '../../components/TidyPreview';
+import { fileTypeNames } from '../../files';
 import type { Tag } from '../../spaces';
 import { useAction } from '../../useAction';
 import { useResource } from '../../useResource';
@@ -14,6 +15,7 @@ interface Rule {
   spaceId: string;
   titleContains: string;
   kind: string | null;
+  fileType: string | null;
   tag: Tag;
   enabled: boolean;
   createdAt: string;
@@ -29,6 +31,12 @@ const kindNames: Record<string, string> = {
   file: 'files',
 };
 
+function ruleText(rule: Rule) {
+  const words = rule.titleContains && `“${rule.titleContains}” in the title`;
+  if (rule.fileType) return `${fileTypeNames[rule.fileType]}${words ? ` with ${words}` : ''}`;
+  return `Title contains “${rule.titleContains}”${rule.kind ? `, ${kindNames[rule.kind]} only` : ''}`;
+}
+
 export function TidyRules({ tags }: { tags: Tag[] }) {
   const auth = useAuth();
   const space = useSpace();
@@ -45,7 +53,7 @@ export function TidyRules({ tags }: { tags: Tag[] }) {
       <div>
         <h2 className="m-0 text-xl font-medium">Tagging rules</h2>
         <p className="mt-2 mb-0 text-sm text-muted">
-          Tag new items in this space by words in their title.
+          Tag new items in this space by words in their title, by file type, or both.
         </p>
       </div>
       {rules.error ? (
@@ -59,7 +67,7 @@ export function TidyRules({ tags }: { tags: Tag[] }) {
               <li className="flex flex-wrap items-center justify-between gap-4 border-b border-line-soft py-3" key={rule.id}>
                 <div className="min-w-0">
                   <p className="m-0 flex flex-wrap items-center gap-2 text-ink">
-                    Title contains “{rule.titleContains}”{rule.kind && `, ${kindNames[rule.kind]} only`} → <TagChip color={rule.tag.color} label={rule.tag.name} />
+                    {ruleText(rule)} → <TagChip color={rule.tag.color} label={rule.tag.name} />
                   </p>
                   <p className="mono-sm mt-1 mb-0 text-faint">{rule.enabled ? 'On' : 'Paused'}</p>
                 </div>
@@ -118,8 +126,10 @@ export function TidyRules({ tags }: { tags: Tag[] }) {
             onSubmit={(event) => {
               event.preventDefault();
               const target = event.currentTarget;
-              if (!form.check(target, { titleContains: [required('Enter the words to look for.'), atMost(100, 'Use at most 100 characters.')] })) return;
               const values = new FormData(target);
+              const fileType = values.get('fileType');
+              const limit = atMost(100, 'Use at most 100 characters.');
+              if (!form.check(target, { titleContains: fileType ? [limit] : [required('Enter words to look for, or choose a file type.'), limit] })) return;
               void creating
                 .run(async () => {
                   const created = await auth.request<Rule>(`/spaces/${space.id}/tidy-rules`, {
@@ -127,18 +137,32 @@ export function TidyRules({ tags }: { tags: Tag[] }) {
                     body: JSON.stringify({
                       titleContains: String(values.get('titleContains')).trim(),
                       tagId: values.get('tagId'),
-                      ...(values.get('kind') ? { kind: values.get('kind') } : {}),
+                      ...(fileType ? { fileType } : values.get('kind') ? { kind: values.get('kind') } : {}),
                     }),
                   });
                   rules.mutate((current) => [...current, created]);
-                  return `New items with “${created.titleContains}” in the title will be tagged ${created.tag.name}.`;
+                  const words = created.titleContains && `“${created.titleContains}” in the title`;
+                  return created.fileType
+                    ? `${fileTypeNames[created.fileType]} uploaded from now on${words ? ` with ${words}` : ''} will be tagged ${created.tag.name}.`
+                    : `New items with ${words} will be tagged ${created.tag.name}.`;
                 }, 'Could not add the rule')
                 .then((added) => added && target.reset());
             }}
           >
             <h3 className="m-0 text-base font-medium">New rule</h3>
             <TextField label="Title contains" maxLength={100} {...form.field('titleContains')} />
-            <div className="grid gap-4 sm:grid-cols-2">
+            <div className="grid gap-4 sm:grid-cols-3">
+              <label className="field-label">
+                File type
+                <select defaultValue="" name="fileType">
+                  <option value="">Any</option>
+                  {Object.entries(fileTypeNames).map(([value, label]) => (
+                    <option key={value} value={value}>
+                      {label}
+                    </option>
+                  ))}
+                </select>
+              </label>
               <label className="field-label">
                 Kind of item
                 <select defaultValue="" name="kind">
@@ -177,9 +201,9 @@ export function TidyRules({ tags }: { tags: Tag[] }) {
             await auth.request(`/tidy-rules/${deleting.id}`, { method: 'DELETE' });
             rules.mutate((current) => current.filter((rule) => rule.id !== deleting.id));
           }}
-          title={`Delete the rule for “${deleting.titleContains}”?`}
+          title="Delete this rule?"
         >
-          Items it already tagged keep the tag.
+          {ruleText(deleting)}. Items it already tagged keep the tag.
         </ConfirmDialog>
       )}
 
diff --git a/app/frontend/test/tidy.spec.tsx b/app/frontend/test/tidy.spec.tsx
index 3a97d2c..5bc9c92 100644
--- a/app/frontend/test/tidy.spec.tsx
+++ b/app/frontend/test/tidy.spec.tsx
@@ -148,6 +148,39 @@ describe('Tidy', () => {
     expect(fetchMock).toHaveBeenCalledWith('/api/v1/tidy/apply', expect.objectContaining({ method: 'POST' }));
     expect(container.textContent).toContain('Tagged 1 item Finance. You can undo it from Tidy.');
   });
+
+  it('adds a rule for a file type without words to look for', async () => {
+    const rule = { id: 'pdfs', spaceId: 'club', titleContains: '', kind: null, fileType: 'pdf', tag: finance, enabled: true, createdAt: '2026-10-05T10:00:00Z' };
+    const sent: unknown[] = [];
+    serve((path, init) => {
+      if (path === '/spaces/club') return json(club);
+      if (path === '/spaces/club/tags') return json([finance]);
+      if (path === '/spaces/club/tidy-rules' && init?.method === 'POST') {
+        sent.push(JSON.parse(String(init.body)));
+        return json(rule, 201);
+      }
+      if (path === '/spaces/club/tidy-rules') return json([]);
+      return undefined;
+    });
+    await render('/spaces/club/tags');
+
+    const form = [...container.querySelectorAll('form')].find((candidate) => candidate.textContent?.includes('New rule'))!;
+    await act(async () => {
+      form.dispatchEvent(new Event('submit', { bubbles: true, cancelable: true }));
+    });
+    expect(container.textContent).toContain('Enter words to look for, or choose a file type.');
+    expect(sent).toEqual([]);
+
+    form.querySelector<HTMLSelectElement>('select[name="fileType"]')!.value = 'pdf';
+    form.querySelector<HTMLSelectElement>('select[name="kind"]')!.value = 'note';
+    await act(async () => {
+      form.dispatchEvent(new Event('submit', { bubbles: true, cancelable: true }));
+    });
+    expect(sent).toEqual([{ titleContains: '', fileType: 'pdf', tagId: 'finance' }]);
+    expect(container.textContent).toContain('PDFs uploaded from now on will be tagged Finance.');
+    expect(container.textContent).toContain('PDFs → Finance');
+  });
+
   it('finds duplicate files in a local folder without uploading them and deletes the chosen copy', async () => {
     const fetchMock = serve(() => undefined);
     await render('/tidy?view=folder');
diff --git a/app/server/prisma/migrations/20261005100000_tidy_file_types/migration.sql b/app/server/prisma/migrations/20261005100000_tidy_file_types/migration.sql
new file mode 100644
index 0000000..da300da
--- /dev/null
+++ b/app/server/prisma/migrations/20261005100000_tidy_file_types/migration.sql
@@ -0,0 +1,3 @@
+ALTER TABLE "tidy_rules" ADD COLUMN "file_type" TEXT;
+
+ALTER TABLE "tidy_rules" ALTER COLUMN "title_contains" SET DEFAULT '';
diff --git a/app/server/prisma/schema.prisma b/app/server/prisma/schema.prisma
index b063ee5..ea7c754 100644
--- a/app/server/prisma/schema.prisma
+++ b/app/server/prisma/schema.prisma
@@ -628,8 +628,9 @@ model TidyRule {
   id            String      @id @default(uuid()) @db.Uuid
   spaceId       String      @map("space_id") @db.Uuid
   createdById   String      @map("created_by") @db.Uuid
-  titleContains String      @map("title_contains")
+  titleContains String      @default("") @map("title_contains")
   kind          ItemKind?
+  fileType      String?     @map("file_type")
   tagId         String      @map("tag_id") @db.Uuid
   enabled       Boolean     @default(true)
   checkedUntil  DateTime    @map("checked_until")
diff --git a/app/server/src/files/file-inspection.ts b/app/server/src/files/file-inspection.ts
index 370b99f..7c29205 100644
--- a/app/server/src/files/file-inspection.ts
+++ b/app/server/src/files/file-inspection.ts
@@ -13,14 +13,14 @@ interface Image {
 
 export const inlineTypes = new Set(['image/jpeg', 'image/png', 'image/gif', 'image/webp']);
 
-const officeTypes: Record<string, string> = {
+export const officeTypes = {
   docx: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
   xlsx: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
   pptx: 'application/vnd.openxmlformats-officedocument.presentationml.presentation',
   odt: 'application/vnd.oasis.opendocument.text',
   ods: 'application/vnd.oasis.opendocument.spreadsheet',
   odp: 'application/vnd.oasis.opendocument.presentation',
-};
+} as const;
 
 const jpegFrameMarkers = new Set([0xc0, 0xc1, 0xc2, 0xc3, 0xc5, 0xc6, 0xc7, 0xc9, 0xca, 0xcb, 0xcd, 0xce, 0xcf]);
 const jpegMetadataMarkers = new Set([0xe1, 0xed, 0xfe]);
@@ -149,7 +149,7 @@ export function inspectFile(data: Buffer, name: string): InspectedFile | null {
   }
   if (data.toString('latin1', 0, 5) === '%PDF-') return attachment('application/pdf', data);
   if (startsWith(data, 0x50, 0x4b, 0x03, 0x04) || startsWith(data, 0x50, 0x4b, 0x05, 0x06)) {
-    return attachment(officeTypes[name.split('.').pop()?.toLowerCase() ?? ''] ?? 'application/zip', data);
+    return attachment(officeTypes[(name.split('.').pop()?.toLowerCase() ?? '') as keyof typeof officeTypes] ?? 'application/zip', data);
   }
   const content = text(data);
   if (content === null) return null;
diff --git a/app/server/src/tidy/dto/tidy.dto.ts b/app/server/src/tidy/dto/tidy.dto.ts
index 8a2a0ce..8af48d4 100644
--- a/app/server/src/tidy/dto/tidy.dto.ts
+++ b/app/server/src/tidy/dto/tidy.dto.ts
@@ -1,5 +1,6 @@
 import { ArrayMaxSize, ArrayNotEmpty, ArrayUnique, IsArray, IsBoolean, IsIn, IsOptional, IsString, IsUUID, Length, ValidateIf } from 'class-validator';
 import { itemKinds } from '../../items/dto/items.dto';
+import { fileTypes } from '../file-types';
 import { Trimmed } from '../../validation/trimmed.decorator';
 
 export const tidyActions = ['archive', 'trash', 'tag', 'cancel'] as const;
@@ -22,10 +23,15 @@ export class TidyActionDto {
 }
 
 export class CreateTidyRuleDto {
+  @IsOptional()
   @Trimmed()
   @IsString()
-  @Length(1, 100, { message: 'Enter 1 to 100 characters to look for.' })
-  titleContains!: string;
+  @Length(0, 100, { message: 'Look for at most 100 characters.' })
+  titleContains?: string;
+
+  @IsOptional()
+  @IsIn(Object.keys(fileTypes), { message: 'Choose a file type from the list.' })
+  fileType?: string;
 
   @IsOptional()
   @IsIn(itemKinds, { message: 'That is not a kind of item.' })
diff --git a/app/server/src/tidy/file-types.ts b/app/server/src/tidy/file-types.ts
new file mode 100644
index 0000000..99e79db
--- /dev/null
+++ b/app/server/src/tidy/file-types.ts
@@ -0,0 +1,14 @@
+import { Prisma } from '@prisma/client';
+import { officeTypes } from '../files/file-inspection';
+
+export const fileTypes = {
+  image: { startsWith: 'image/' },
+  pdf: { equals: 'application/pdf' },
+  document: { in: [officeTypes.docx, officeTypes.odt] },
+  spreadsheet: { in: [officeTypes.xlsx, officeTypes.ods] },
+  presentation: { in: [officeTypes.pptx, officeTypes.odp] },
+  archive: { equals: 'application/zip' },
+  text: { equals: 'text/plain' },
+} satisfies Record<string, Prisma.StringFilter>;
+
+export type FileType = keyof typeof fileTypes;
diff --git a/app/server/src/tidy/tidy-rules.service.ts b/app/server/src/tidy/tidy-rules.service.ts
index 25fee3d..f3fd556 100644
--- a/app/server/src/tidy/tidy-rules.service.ts
+++ b/app/server/src/tidy/tidy-rules.service.ts
@@ -5,6 +5,7 @@ import { MaintenanceScheduler } from '../jobs/maintenance.scheduler';
 import { PrismaService } from '../prisma/prisma.service';
 import { presentTag, tagFields } from '../tags/tags.service';
 import { CreateTidyRuleDto } from './dto/tidy.dto';
+import { fileTypes, type FileType } from './file-types';
 
 const settleMs = 60_000;
 
@@ -13,6 +14,7 @@ const ruleFields = {
   spaceId: true,
   titleContains: true,
   kind: true,
+  fileType: true,
   enabled: true,
   createdAt: true,
   tag: { select: tagFields },
@@ -24,18 +26,20 @@ function presentRule(rule: Prisma.TidyRuleGetPayload<{ select: typeof ruleFields
     spaceId: rule.spaceId,
     titleContains: rule.titleContains,
     kind: rule.kind?.toLowerCase() ?? null,
+    fileType: rule.fileType,
     tag: presentTag(rule.tag),
     enabled: rule.enabled,
     createdAt: rule.createdAt,
   };
 }
 
-function matching(rule: { spaceId: string; titleContains: string; kind: ItemKind | null; tagId: string }) {
+function matching(rule: { spaceId: string; titleContains: string; kind: ItemKind | null; fileType: string | null; tagId: string }) {
   return {
     spaceId: rule.spaceId,
     trashedAt: null,
     kind: rule.kind ?? undefined,
-    title: { contains: rule.titleContains, mode: 'insensitive' },
+    title: rule.titleContains ? { contains: rule.titleContains, mode: 'insensitive' } : undefined,
+    file: rule.fileType ? { mimeType: fileTypes[rule.fileType as FileType] } : undefined,
     tags: { none: { tagId: rule.tagId } },
   } satisfies Prisma.ItemWhereInput;
 }
@@ -64,6 +68,7 @@ export class TidyRulesService implements OnModuleInit {
 
   async create(userId: string, spaceId: string, input: CreateTidyRuleDto) {
     await this.access.assertSpace(userId, spaceId, 'edit');
+    if (!input.titleContains && !input.fileType) throw new BadRequestException('Look for words in the title, a file type, or both');
     if (!(await this.prisma.tag.count({ where: { id: input.tagId, spaceId } }))) {
       throw new BadRequestException("Choose a tag from this rule's space");
     }
@@ -71,7 +76,8 @@ export class TidyRulesService implements OnModuleInit {
       data: {
         spaceId,
         createdById: userId,
-        titleContains: input.titleContains,
+        titleContains: input.titleContains ?? '',
+        fileType: input.fileType ?? null,
         kind: input.kind ? (input.kind.toUpperCase() as ItemKind) : null,
         tagId: input.tagId,
         checkedUntil: new Date(),
@@ -99,7 +105,7 @@ export class TidyRulesService implements OnModuleInit {
   async matches(userId: string, ruleId: string) {
     const rule = await this.prisma.tidyRule.findFirst({
       where: { id: ruleId, space: this.access.spacesOf(userId) },
-      select: { spaceId: true, titleContains: true, kind: true, tagId: true },
+      select: { spaceId: true, titleContains: true, kind: true, fileType: true, tagId: true },
     });
     if (!rule) throw new NotFoundException('Rule not found');
     const [total, items] = await this.prisma.$transaction([
@@ -118,7 +124,7 @@ export class TidyRulesService implements OnModuleInit {
     const until = new Date(now.getTime() - settleMs);
     const rules = await this.prisma.tidyRule.findMany({
       where: { enabled: true, checkedUntil: { lt: until } },
-      select: { id: true, spaceId: true, createdById: true, titleContains: true, kind: true, tagId: true, checkedUntil: true },
+      select: { id: true, spaceId: true, createdById: true, titleContains: true, kind: true, fileType: true, tagId: true, checkedUntil: true },
       take: 500,
     });
     for (const rule of rules) {
diff --git a/app/server/src/tidy/tidy.service.ts b/app/server/src/tidy/tidy.service.ts
index 91b35ba..7aa34fa 100644
--- a/app/server/src/tidy/tidy.service.ts
+++ b/app/server/src/tidy/tidy.service.ts
@@ -32,7 +32,7 @@ const batchFields = {
   createdAt: true,
   undoneAt: true,
   tag: { select: tagFields },
-  rule: { select: { id: true, titleContains: true } },
+  rule: { select: { id: true, titleContains: true, fileType: true } },
   _count: { select: { changes: true } },
 } satisfies Prisma.TidyBatchSelect;
 
diff --git a/app/server/test/integration/tidy.spec.ts b/app/server/test/integration/tidy.spec.ts
index 162e2c1..ebf3b15 100644
--- a/app/server/test/integration/tidy.spec.ts
+++ b/app/server/test/integration/tidy.spec.ts
@@ -162,6 +162,29 @@ describe('Tidy against Postgres', () => {
     expect((await owner.call('GET', `/tidy-rules/${rule.id}/matches`)).status).toBe(404);
   });
 
+  it('matches rules by file type, with or without words in the title', async () => {
+    const owner = await member('filer');
+    const papers = (await owner.call('POST', `/spaces/${owner.personalSpaceId}/tags`, { name: 'Papers' })).body;
+    const pdf = await file(owner, owner.personalSpaceId, 'lease.pdf', Buffer.from(`%PDF-1.4 lease ${owner.id}`));
+    await file(owner, owner.personalSpaceId, 'lease.txt', Buffer.from(`lease ${owner.id}`));
+    await strata.item(owner.personalSpaceId, 'lease notes');
+
+    expect((await owner.call('POST', `/spaces/${owner.personalSpaceId}/tidy-rules`, { tagId: papers.id })).status).toBe(400);
+    expect((await owner.call('POST', `/spaces/${owner.personalSpaceId}/tidy-rules`, { fileType: 'video', tagId: papers.id })).status).toBe(400);
+    const rule = (await owner.call('POST', `/spaces/${owner.personalSpaceId}/tidy-rules`, { fileType: 'pdf', tagId: papers.id })).body;
+    expect(rule).toMatchObject({ titleContains: '', fileType: 'pdf', kind: null });
+    expect(ids((await owner.call('GET', `/tidy-rules/${rule.id}/matches`)).body.results)).toEqual([pdf.id]);
+
+    const both = (await owner.call('POST', `/spaces/${owner.personalSpaceId}/tidy-rules`, { titleContains: 'invoice', fileType: 'pdf', tagId: papers.id })).body;
+    expect((await owner.call('GET', `/tidy-rules/${both.id}/matches`)).body.total).toBe(0);
+
+    const later = await file(owner, owner.personalSpaceId, 'invoice.pdf', Buffer.from(`%PDF-1.4 invoice ${owner.id}`));
+    await file(owner, owner.personalSpaceId, 'invoice.txt', Buffer.from(`invoice ${owner.id}`));
+    await strata.service(TidyRulesService).applyRules(new Date(Date.now() + 2 * 60_000));
+    const tagged = await strata.prisma.itemTag.findMany({ where: { tagId: papers.id }, select: { itemId: true } });
+    expect(tagged.map((entry) => entry.itemId)).toEqual([later.id]);
+  });
+
   it('schedules a weekly summary for people who turned it on and sends it only when there is clutter', async () => {
     const keen = await member('weekly');
     const quiet = await member('quiet');