diff --git a/server/src/mcp/resources.ts b/server/src/mcp/resources.ts
index ec84a232c..5b2645e63 100644
--- a/server/src/mcp/resources.ts
+++ b/server/src/mcp/resources.ts
@@ -5,7 +5,6 @@ import { listDays, listAccommodations } from '../services/dayService';
 import { listPlaces } from '../services/placeService';
 import { listBudgetItems, getPerPersonSummary, calculateSettlement } from '../services/budgetService';
 import { listReservations } from '../services/reservationService';
-import { listNotes as listDayNotes } from '../services/dayNoteService';
 import { listNotes as listCollabNotes, listPolls, listMessages } from '../services/collabService';
 import { listBucketList, listVisitedCountries, getStats as getAtlasStats, listManuallyVisitedRegions } from '../services/atlasService';
 import { getNotifications } from '../services/inAppNotifications';
@@ -132,19 +131,8 @@ export function registerResources(server: McpServer, userId: number, scopes: str
     }
   );
 
-  // Day notes
-  if (canReadTrips(scopes)) server.registerResource(
-    'day-notes',
-    new ResourceTemplate('trek://trips/{tripId}/days/{dayId}/notes', { list: undefined }),
-    { description: 'Notes for a specific day in a trip', mimeType: 'application/json' },
-    async (uri, { tripId, dayId }) => {
-      const tId = parseId(tripId);
-      const dId = parseId(dayId);
-      if (tId === null || dId === null || !canAccessTrip(tId, userId)) return accessDenied(uri.href);
-      const notes = listDayNotes(dId, tId);
-      return jsonContent(uri.href, notes);
-    }
-  );
+  // The day-notes resource moved to the DI-discovered
+  // src/nest/days/day-notes.mcp.ts (@ResourceTemplate).
 
   // Accommodations (hotels, rentals) per trip
   if (canReadTrips(scopes)) server.registerResource(
diff --git a/server/src/mcp/tools/days.ts b/server/src/mcp/tools/days.ts
index 4ea491d0f..30fc7962b 100644
--- a/server/src/mcp/tools/days.ts
+++ b/server/src/mcp/tools/days.ts
@@ -8,10 +8,6 @@ import {
   createAccommodation, getAccommodation, updateAccommodation, deleteAccommodation,
 } from '../../services/dayService';
 import { createPlace } from '../../services/placeService';
-import {
-  createNote as createDayNote, getNote as getDayNote, updateNote as updateDayNote,
-  deleteNote as deleteDayNote, dayExists as dayNoteExists,
-} from '../../services/dayNoteService';
 import {
   safeBroadcast, TOOL_ANNOTATIONS_WRITE, TOOL_ANNOTATIONS_DELETE,
   TOOL_ANNOTATIONS_NON_IDEMPOTENT,
@@ -221,78 +217,6 @@ export function registerDayTools(server: McpServer, userId: number, scopes: stri
     }
   );
 
-  // --- DAY NOTES ---
-
-  server.registerTool(
-    'create_day_note',
-    {
-      description: 'Add a note to a specific day in a trip.',
-      inputSchema: {
-        tripId: z.number().int().positive(),
-        dayId: z.number().int().positive(),
-        text: z.string().min(1).max(500),
-        time: z.string().max(250).optional().describe('Time label (e.g. "09:00" or "Morning")'),
-        icon: z.string().optional().describe('Emoji icon for the note'),
-      },
-      annotations: TOOL_ANNOTATIONS_NON_IDEMPOTENT,
-    },
-    async ({ tripId, dayId, text, time, icon }) => {
-      if (isDemoUser(userId)) return demoDenied();
-      if (!canAccessTrip(tripId, userId)) return noAccess();
-      if (!hasTripPermission('day_edit', tripId, userId)) return permissionDenied();
-      if (!dayNoteExists(dayId, tripId)) return { content: [{ type: 'text' as const, text: 'Day not found.' }], isError: true };
-      const note = createDayNote(dayId, tripId, text, time, icon);
-      safeBroadcast(tripId, 'dayNote:created', { dayId, note });
-      return ok({ note });
-    }
-  );
-
-  server.registerTool(
-    'update_day_note',
-    {
-      description: 'Edit an existing note on a specific day.',
-      inputSchema: {
-        tripId: z.number().int().positive(),
-        dayId: z.number().int().positive(),
-        noteId: z.number().int().positive(),
-        text: z.string().min(1).max(500).optional(),
-        time: z.string().max(250).nullable().optional().describe('Time label (e.g. "09:00" or "Morning"), or null to clear'),
-        icon: z.string().optional().describe('Emoji icon for the note'),
-      },
-      annotations: TOOL_ANNOTATIONS_WRITE,
-    },
-    async ({ tripId, dayId, noteId, text, time, icon }) => {
-      if (isDemoUser(userId)) return demoDenied();
-      if (!canAccessTrip(tripId, userId)) return noAccess();
-      if (!hasTripPermission('day_edit', tripId, userId)) return permissionDenied();
-      const existing = getDayNote(noteId, dayId, tripId);
-      if (!existing) return { content: [{ type: 'text' as const, text: 'Note not found.' }], isError: true };
-      const note = updateDayNote(noteId, existing, { text, time: time !== undefined ? time : undefined, icon });
-      safeBroadcast(tripId, 'dayNote:updated', { dayId, note });
-      return ok({ note });
-    }
-  );
-
-  server.registerTool(
-    'delete_day_note',
-    {
-      description: 'Delete a note from a specific day.',
-      inputSchema: {
-        tripId: z.number().int().positive(),
-        dayId: z.number().int().positive(),
-        noteId: z.number().int().positive(),
-      },
-      annotations: TOOL_ANNOTATIONS_DELETE,
-    },
-    async ({ tripId, dayId, noteId }) => {
-      if (isDemoUser(userId)) return demoDenied();
-      if (!canAccessTrip(tripId, userId)) return noAccess();
-      if (!hasTripPermission('day_edit', tripId, userId)) return permissionDenied();
-      const note = getDayNote(noteId, dayId, tripId);
-      if (!note) return { content: [{ type: 'text' as const, text: 'Note not found.' }], isError: true };
-      deleteDayNote(noteId);
-      safeBroadcast(tripId, 'dayNote:deleted', { noteId, dayId });
-      return ok({ success: true });
-    }
-  );
+  // The day-note tools (create/update/delete_day_note) moved to the
+  // DI-discovered src/nest/days/day-notes.mcp.ts (@McpController).
 }
diff --git a/server/src/nest/README.md b/server/src/nest/README.md
index 86af56f9b..a9ffab7c8 100644
--- a/server/src/nest/README.md
+++ b/server/src/nest/README.md
@@ -27,7 +27,7 @@ mount to Nest and leaves the sibling trip routes (days, places, ...) on Express.
   categories, tags, notifications, atlas.
 - **Phase 2 (trip sub-domains):** vacay (addon), packing, todo.
 - **DI-native services (legacy `src/services/*` deleted):** tags, categories,
-  todo, packing — see the migration recipe below.
+  todo, packing, day-notes — see the migration recipe below.
 
 ## Cross-cutting Foundation pieces
 
@@ -101,8 +101,11 @@ first in-container consumer wiring: `TripsService` injects `TodoService` via
 `exports: [TodoService]` instead of using the bridge); packing followed (the
 largest port so far: a 17-tool + 2-resource `packing.mcp.ts` with inline admin
 gates, and the first `PluginHostDepsFactory` swap done as part of a service
-migration — no bridge entry for the plugin host). Repeat these steps per
-service (next up: dayNoteService). This is a **pure relocation** — byte-identical
+migration — no bridge entry for the plugin host); day-notes followed (the first
+migration needing **no bridge at all**: after its three tools + resource moved
+to `day-notes.mcp.ts` and the plugin host injection, nothing outside the
+container consumed it). Repeat these steps per
+service (next up: tripInviteService). This is a **pure relocation** — byte-identical
 SQL, statuses, bodies, and error strings. The plugin RPC host is **no longer a
 bridge consumer**: since Option A of `src/nest/plugins/DI-MIGRATION.md` it
 injects domain services via `PluginHostDepsFactory`, so a migrated domain adds
diff --git a/server/src/nest/days/day-notes.mcp.ts b/server/src/nest/days/day-notes.mcp.ts
new file mode 100644
index 000000000..49bd41148
--- /dev/null
+++ b/server/src/nest/days/day-notes.mcp.ts
@@ -0,0 +1,134 @@
+import {
+  McpController, Tool, ResourceTemplate, type McpContext,
+  TOOL_ANNOTATIONS_WRITE, TOOL_ANNOTATIONS_DELETE, TOOL_ANNOTATIONS_NON_IDEMPOTENT,
+  demoDenied, ok,
+} from '@trek/nest-mcp';
+import { z } from 'zod';
+import { isDemoUser } from '../../services/authService';
+import { safeBroadcast, noAccess, hasTripPermission, permissionDenied } from '../../mcp/tools/_shared';
+import { DayNotesService } from './day-notes.service';
+
+function parseId(value: string | string[]): number | null {
+  const n = Number(Array.isArray(value) ? value[0] : value);
+  return Number.isInteger(n) && n > 0 ? n : null;
+}
+
+/**
+ * Day-note MCP surface — ported 1:1 from the legacy registrars: the three
+ * tools from the DAY NOTES block of src/mcp/tools/days.ts and the
+ * trek://trips/{tripId}/days/{dayId}/notes resource from src/mcp/resources.ts
+ * (identical names, descriptions, schemas, annotations, error/payload shapes
+ * and broadcasts). The legacy registration-time gates map to the declarative
+ * trips write/read access markers (registerDayTools' whole-registrar
+ * `canWrite(scopes, 'trips')` early return and the resource's canReadTrips
+ * check, resolved by trekMcpAccessPolicy). No addon gate — day notes are core.
+ */
+@McpController()
+export class DayNotesMcp {
+  constructor(private readonly notes: DayNotesService) {}
+
+  @Tool({
+    name: 'create_day_note',
+    description: 'Add a note to a specific day in a trip.',
+    inputSchema: {
+      tripId: z.number().int().positive(),
+      dayId: z.number().int().positive(),
+      text: z.string().min(1).max(500),
+      time: z.string().max(250).optional().describe('Time label (e.g. "09:00" or "Morning")'),
+      icon: z.string().optional().describe('Emoji icon for the note'),
+    },
+    annotations: TOOL_ANNOTATIONS_NON_IDEMPOTENT,
+    access: { group: 'trips', mode: 'write' },
+  })
+  async createDayNote(
+    { tripId, dayId, text, time, icon }: { tripId: number; dayId: number; text: string; time?: string; icon?: string },
+    ctx: McpContext,
+  ) {
+    if (isDemoUser(ctx.userId)) return demoDenied();
+    if (!this.notes.verifyTripAccess(tripId, ctx.userId)) return noAccess();
+    if (!hasTripPermission('day_edit', tripId, ctx.userId)) return permissionDenied();
+    if (!this.notes.dayExists(dayId, tripId)) return { content: [{ type: 'text' as const, text: 'Day not found.' }], isError: true };
+    const note = this.notes.create(dayId, tripId, text, time, icon);
+    safeBroadcast(tripId, 'dayNote:created', { dayId, note });
+    return ok({ note });
+  }
+
+  @Tool({
+    name: 'update_day_note',
+    description: 'Edit an existing note on a specific day.',
+    inputSchema: {
+      tripId: z.number().int().positive(),
+      dayId: z.number().int().positive(),
+      noteId: z.number().int().positive(),
+      text: z.string().min(1).max(500).optional(),
+      time: z.string().max(250).nullable().optional().describe('Time label (e.g. "09:00" or "Morning"), or null to clear'),
+      icon: z.string().optional().describe('Emoji icon for the note'),
+    },
+    annotations: TOOL_ANNOTATIONS_WRITE,
+    access: { group: 'trips', mode: 'write' },
+  })
+  async updateDayNote(
+    { tripId, dayId, noteId, text, time, icon }: { tripId: number; dayId: number; noteId: number; text?: string; time?: string | null; icon?: string },
+    ctx: McpContext,
+  ) {
+    if (isDemoUser(ctx.userId)) return demoDenied();
+    if (!this.notes.verifyTripAccess(tripId, ctx.userId)) return noAccess();
+    if (!hasTripPermission('day_edit', tripId, ctx.userId)) return permissionDenied();
+    const existing = this.notes.getNote(noteId, dayId, tripId);
+    if (!existing) return { content: [{ type: 'text' as const, text: 'Note not found.' }], isError: true };
+    const note = this.notes.update(noteId, existing, { text, time: time !== undefined ? time : undefined, icon });
+    safeBroadcast(tripId, 'dayNote:updated', { dayId, note });
+    return ok({ note });
+  }
+
+  @Tool({
+    name: 'delete_day_note',
+    description: 'Delete a note from a specific day.',
+    inputSchema: {
+      tripId: z.number().int().positive(),
+      dayId: z.number().int().positive(),
+      noteId: z.number().int().positive(),
+    },
+    annotations: TOOL_ANNOTATIONS_DELETE,
+    access: { group: 'trips', mode: 'write' },
+  })
+  async deleteDayNote({ tripId, dayId, noteId }: { tripId: number; dayId: number; noteId: number }, ctx: McpContext) {
+    if (isDemoUser(ctx.userId)) return demoDenied();
+    if (!this.notes.verifyTripAccess(tripId, ctx.userId)) return noAccess();
+    if (!hasTripPermission('day_edit', tripId, ctx.userId)) return permissionDenied();
+    const note = this.notes.getNote(noteId, dayId, tripId);
+    if (!note) return { content: [{ type: 'text' as const, text: 'Note not found.' }], isError: true };
+    this.notes.remove(noteId);
+    safeBroadcast(tripId, 'dayNote:deleted', { noteId, dayId });
+    return ok({ success: true });
+  }
+
+  @ResourceTemplate({
+    name: 'day-notes',
+    uriTemplate: 'trek://trips/{tripId}/days/{dayId}/notes',
+    description: 'Notes for a specific day in a trip',
+    mimeType: 'application/json',
+    access: { group: 'trips', mode: 'read' },
+  })
+  async dayNotesResource(uri: URL, { tripId, dayId }: { tripId: string | string[]; dayId: string | string[] }, ctx: McpContext) {
+    const tId = parseId(tripId);
+    const dId = parseId(dayId);
+    if (tId === null || dId === null || !this.notes.verifyTripAccess(tId, ctx.userId)) {
+      return {
+        contents: [{
+          uri: uri.href,
+          mimeType: 'application/json',
+          text: JSON.stringify({ error: 'Trip not found or access denied' }),
+        }],
+      };
+    }
+    const notes = this.notes.list(dId, tId);
+    return {
+      contents: [{
+        uri: uri.href,
+        mimeType: 'application/json',
+        text: JSON.stringify(notes, null, 2),
+      }],
+    };
+  }
+}
diff --git a/server/src/nest/days/day-notes.service.ts b/server/src/nest/days/day-notes.service.ts
index b43cde8b6..a779c0089 100644
--- a/server/src/nest/days/day-notes.service.ts
+++ b/server/src/nest/days/day-notes.service.ts
@@ -1,22 +1,25 @@
 import { Injectable } from '@nestjs/common';
 import { broadcast } from '../../websocket';
 import { checkPermission } from '../../services/permissions';
-import type { User } from '../../types';
-import * as dayNoteService from '../../services/dayNoteService';
-
-type Trip = NonNullable<ReturnType<typeof dayNoteService.verifyTripAccess>>;
+import type { DayNote, User } from '../../types';
+import { DatabaseService, type TripAccess } from '../database/database.service';
 
 /**
- * Thin Nest wrapper around the existing day-note service. Trip access + the
- * 'day_edit' permission reuse the legacy checks; the SQL is unchanged.
+ * Day-notes domain service — the legacy dayNoteService SQL folded in over
+ * the injected DatabaseService (byte-identical statements and
+ * coercions). Trip access rides DatabaseService.canAccessTrip (absorbing the
+ * legacy services/tripAccess re-export); the 'day_edit' permission reuses the
+ * legacy check.
  */
 @Injectable()
 export class DayNotesService {
-  verifyTripAccess(tripId: string, userId: number) {
-    return dayNoteService.verifyTripAccess(tripId, userId);
+  constructor(private readonly dbs: DatabaseService) {}
+
+  verifyTripAccess(tripId: string | number, userId: number): TripAccess | undefined {
+    return this.dbs.canAccessTrip(tripId, userId);
   }
 
-  canEdit(trip: Trip, user: User): boolean {
+  canEdit(trip: TripAccess, user: User): boolean {
     return checkPermission('day_edit', user.role, trip.user_id, user.id, trip.user_id !== user.id);
   }
 
@@ -24,27 +27,42 @@ export class DayNotesService {
     broadcast(tripId, event, payload, socketId);
   }
 
-  list(dayId: string, tripId: string) {
-    return dayNoteService.listNotes(dayId, tripId);
+  list(dayId: string | number, tripId: string | number) {
+    return this.dbs.all(
+      'SELECT * FROM day_notes WHERE day_id = ? AND trip_id = ? ORDER BY sort_order ASC, created_at ASC',
+      dayId, tripId,
+    );
   }
 
-  dayExists(dayId: string, tripId: string) {
-    return dayNoteService.dayExists(dayId, tripId);
+  dayExists(dayId: string | number, tripId: string | number) {
+    return this.dbs.get('SELECT id FROM days WHERE id = ? AND trip_id = ?', dayId, tripId);
   }
 
-  getNote(id: string, dayId: string, tripId: string) {
-    return dayNoteService.getNote(id, dayId, tripId);
+  getNote(id: string | number, dayId: string | number, tripId: string | number) {
+    return this.dbs.get<DayNote>('SELECT * FROM day_notes WHERE id = ? AND day_id = ? AND trip_id = ?', id, dayId, tripId);
   }
 
-  create(dayId: string, tripId: string, text: string, time?: string, icon?: string, sortOrder?: number) {
-    return dayNoteService.createNote(dayId, tripId, text, time, icon, sortOrder);
+  create(dayId: string | number, tripId: string | number, text: string, time?: string | null, icon?: string | null, sortOrder?: number) {
+    const result = this.dbs.run(
+      'INSERT INTO day_notes (day_id, trip_id, text, time, icon, sort_order) VALUES (?, ?, ?, ?, ?, ?)',
+      dayId, tripId, text.trim(), time || null, icon || '📝', sortOrder ?? 9999,
+    );
+    return this.dbs.get('SELECT * FROM day_notes WHERE id = ?', result.lastInsertRowid);
   }
 
-  update(id: string, current: Parameters<typeof dayNoteService.updateNote>[1], fields: { text?: string; time?: string; icon?: string; sort_order?: number }) {
-    return dayNoteService.updateNote(id, current, fields);
+  update(id: string | number, current: DayNote, fields: { text?: string; time?: string | null; icon?: string | null; sort_order?: number }) {
+    this.dbs.run(
+      'UPDATE day_notes SET text = ?, time = ?, icon = ?, sort_order = ? WHERE id = ?',
+      fields.text !== undefined ? fields.text.trim() : current.text,
+      fields.time !== undefined ? fields.time : current.time,
+      fields.icon !== undefined ? fields.icon : current.icon,
+      fields.sort_order !== undefined ? fields.sort_order : current.sort_order,
+      id,
+    );
+    return this.dbs.get('SELECT * FROM day_notes WHERE id = ?', id);
   }
 
-  remove(id: string): void {
-    dayNoteService.deleteNote(id);
+  remove(id: string | number): void {
+    this.dbs.run('DELETE FROM day_notes WHERE id = ?', id);
   }
 }
diff --git a/server/src/nest/days/days.module.ts b/server/src/nest/days/days.module.ts
index eb19bfe98..84389896c 100644
--- a/server/src/nest/days/days.module.ts
+++ b/server/src/nest/days/days.module.ts
@@ -3,14 +3,17 @@ import { DaysController } from './days.controller';
 import { DaysService } from './days.service';
 import { DayNotesController } from './day-notes.controller';
 import { DayNotesService } from './day-notes.service';
+import { DayNotesMcp } from './day-notes.mcp';
 
 /**
  * Days + day-notes domain (S6 — Phase 2 trip sub-domain). The single prefix
  * /api/trips/:tripId/days covers both the days mount and the nested
- * /days/:dayId/notes mount.
+ * /days/:dayId/notes mount. DayNotesService is exported for the plugin RPC
+ * host (PluginHostDepsFactory).
  */
 @Module({
   controllers: [DaysController, DayNotesController],
-  providers: [DaysService, DayNotesService],
+  providers: [DaysService, DayNotesService, DayNotesMcp],
+  exports: [DayNotesService],
 })
 export class DaysModule {}
diff --git a/server/src/nest/plugins/DI-MIGRATION.md b/server/src/nest/plugins/DI-MIGRATION.md
index 19ac543b7..07d313045 100644
--- a/server/src/nest/plugins/DI-MIGRATION.md
+++ b/server/src/nest/plugins/DI-MIGRATION.md
@@ -98,8 +98,8 @@ is `@Global`, so no import needed for it.
 factory *until their own domain migrates*. Each future migration then swaps one
 import for one injected service (+ module export/import) — **no more bridge
 files for the plugin host, ever**. The factory's import list shrinks
-monotonically as the recipe in `src/nest/README.md` proceeds (packing swapped
-in 2026-07; next up: dayNoteService).
+monotonically as the recipe in `src/nest/README.md` proceeds (packing and
+day-notes swapped in 2026-07; next up: tripInviteService).
 
 ### Test impact (as landed)
 
@@ -215,8 +215,9 @@ none of it is throwaway.
 1. ~~**Now / opportunistically — Option A.**~~ **Done (2026-07).** Injectable
    factory, tags/categories bridges deleted, wiring test rewritten against
    stubs (see §2).
-2. **Per domain, as the service migrations proceed** (`packingService` done
-   2026-07; `dayNoteService` next, per `src/nest/README.md`): migrate the
+2. **Per domain, as the service migrations proceed** (`packingService` and
+   `dayNoteService` done 2026-07; `tripInviteService` next, per
+   `src/nest/README.md`): migrate the
    service to DI as usual; the factory swaps one legacy import for one
    injected service. Optionally pilot `tags.rpc.ts` here — tags is small and
    already fully DI on HTTP + MCP.
diff --git a/server/src/nest/plugins/host/plugin-host-deps.factory.ts b/server/src/nest/plugins/host/plugin-host-deps.factory.ts
index aef14f59b..4f1da5bda 100644
--- a/server/src/nest/plugins/host/plugin-host-deps.factory.ts
+++ b/server/src/nest/plugins/host/plugin-host-deps.factory.ts
@@ -28,7 +28,6 @@ import { ADDON_IDS } from '../../../addons';
 import { listJourneys, listEntries as listJournalEntriesSvc, createEntry as createJournalEntrySvc, updateEntry as updateJournalEntrySvc, deleteEntry as deleteJournalEntrySvc, createJourney as createJourneySvc, deleteJourney as deleteJourneySvc } from '../../../services/journeyService';
 import { listVisitedCountries, listManuallyVisitedRegions, listBucketList, markCountryVisited, unmarkCountryVisited, markRegionVisited, unmarkRegionVisited, createBucketItem as createBucketItemSvc, deleteBucketItem as deleteBucketItemSvc } from '../../../services/atlasService';
 import { getPlanData, getActivePlanId, toggleEntry as vacayToggleEntrySvc, toggleCompanyHoliday as vacayToggleCompanyHolidaySvc } from '../../../services/vacayService';
-import { listNotes, createNote, getNote, updateNote, deleteNote, dayExists as dayNoteDayExists } from '../../../services/dayNoteService';
 import { listCollections, getCollection, createCollection, updateCollection, savePlace as saveCollectionPlaceSvc, copyToTrip as copyCollectionToTripSvc, deletePlace as deleteCollectionPlaceSvc } from '../../../services/collectionsService';
 import { BudgetService } from '../../budget/budget.service';
 import { ReservationsService } from '../../reservations/reservations.service';
@@ -36,6 +35,7 @@ import { TagsService } from '../../tags/tags.service';
 import { CategoriesService } from '../../categories/categories.service';
 import { TodoService } from '../../todo/todo.service';
 import { PackingService } from '../../packing/packing.service';
+import { DayNotesService } from '../../days/day-notes.service';
 import { notifyBookingChange } from '../../../services/reservationService';
 import { PluginRpcHost, ForbiddenResource, BadParams } from './rpc-host';
 import { appendAudit } from './plugin-audit';
@@ -150,9 +150,10 @@ export interface PluginCallRouter {
  * `plugin:{id}:{event}` so a plugin can't forge a core event.
  *
  * DI-native domain services (budget, reservations, tags, categories, todo,
- * packing, oauth) are constructor-injected; legacy `services/*` domains stay
- * plain function imports until their own migration lands (DI-MIGRATION.md), at
- * which point each swaps one import for one injected service.
+ * packing, day-notes, oauth) are constructor-injected; legacy `services/*`
+ * domains stay plain function imports until their own migration lands
+ * (DI-MIGRATION.md), at which point each swaps one import for one injected
+ * service.
  */
 @Injectable()
 export class PluginHostDepsFactory {
@@ -164,6 +165,7 @@ export class PluginHostDepsFactory {
     private readonly todos: TodoService,
     private readonly packing: PackingService,
     private readonly oauth: PluginOAuthService,
+    private readonly dayNotes: DayNotesService,
   ) {}
 
   create(id: string, granted: ReadonlySet<string>, router: PluginCallRouter): PluginRpcHost {
@@ -690,27 +692,27 @@ export class PluginHostDepsFactory {
         return { deleted: true };
       },
       // Day notes are core (no addon) and trip-scoped; membership is enforced by the host.
-      listDayNotes: (tripId, dayId) => listNotes(dayId, tripId),
+      listDayNotes: (tripId, dayId) => this.dayNotes.list(dayId, tripId),
       // --- Day notes write (day_edit). The day must belong to the trip; broadcasts the
       // same dayNote:* events the REST controller emits so open sessions update live. ---
       createDayNote: (tripId, dayId, input) => {
-        if (!dayNoteDayExists(dayId, tripId)) throw new ForbiddenResource(`no day ${dayId} on trip ${tripId}`);
+        if (!this.dayNotes.dayExists(dayId, tripId)) throw new ForbiddenResource(`no day ${dayId} on trip ${tripId}`);
         const i = input as { text?: string; time?: string; icon?: string; sort_order?: number };
-        const note = createNote(dayId, tripId, i.text ?? '', i.time, i.icon, i.sort_order);
+        const note = this.dayNotes.create(dayId, tripId, i.text ?? '', i.time, i.icon, i.sort_order);
         broadcast(tripId, 'dayNote:created', { dayId, note }, undefined);
         return note;
       },
       updateDayNote: (tripId, dayId, noteId, input) => {
-        const current = getNote(noteId, dayId, tripId);
+        const current = this.dayNotes.getNote(noteId, dayId, tripId);
         if (!current) throw new ForbiddenResource(`no note ${noteId} on day ${dayId}`);
-        const note = updateNote(noteId, current as never, input as { text?: string; time?: string; icon?: string; sort_order?: number });
+        const note = this.dayNotes.update(noteId, current as never, input as { text?: string; time?: string; icon?: string; sort_order?: number });
         broadcast(tripId, 'dayNote:updated', { dayId, note }, undefined);
         return note;
       },
       deleteDayNote: (tripId, dayId, noteId) => {
-        const current = getNote(noteId, dayId, tripId);
+        const current = this.dayNotes.getNote(noteId, dayId, tripId);
         if (!current) throw new ForbiddenResource(`no note ${noteId} on day ${dayId}`);
-        deleteNote(noteId);
+        this.dayNotes.remove(noteId);
         broadcast(tripId, 'dayNote:deleted', { noteId, dayId }, undefined);
         return { deleted: true };
       },
diff --git a/server/src/nest/plugins/plugins.module.ts b/server/src/nest/plugins/plugins.module.ts
index b8079bbbc..4a6aa7526 100644
--- a/server/src/nest/plugins/plugins.module.ts
+++ b/server/src/nest/plugins/plugins.module.ts
@@ -30,6 +30,7 @@ import { BudgetModule } from '../budget/budget.module';
 import { ReservationsModule } from '../reservations/reservations.module';
 import { TodoModule } from '../todo/todo.module';
 import { PackingModule } from '../packing/packing.module';
+import { DaysModule } from '../days/days.module';
 
 /**
  * Plugin system (#plugins). M0 read side + M2 isolated runtime + M3 frontend:
@@ -41,7 +42,7 @@ import { PackingModule } from '../packing/packing.module';
 @Module({
   // The DI-native domain services the plugin host wiring injects
   // (PluginHostDepsFactory); DatabaseModule is @Global, so not listed.
-  imports: [TagsModule, CategoriesModule, BudgetModule, ReservationsModule, TodoModule, PackingModule],
+  imports: [TagsModule, CategoriesModule, BudgetModule, ReservationsModule, TodoModule, PackingModule, DaysModule],
   controllers: [PluginsController, PluginsFeedController, PluginsProxyController, PluginFrameController, PlaceDetailsController, TripWarningsController, ViewContributionsController, TripCardContributionsController, PluginPhotosController, PluginCalendarController, MapMarkersController, MapLayersController, PluginRoutesController, DayScheduleController, PdfSectionsController, AtlasLayersController, JournalEntryRowsController, PluginUserSettingsController, PluginOAuthController, PluginActivityController],
   providers: [PluginsService, PluginRuntimeService, PluginRegistryService, PluginOAuthService, PluginHostDepsFactory],
   // Exported so the admin addon-toggle handler can cascade-disable plugins whose
diff --git a/server/src/services/dayNoteService.ts b/server/src/services/dayNoteService.ts
deleted file mode 100644
index 3758678a3..000000000
--- a/server/src/services/dayNoteService.ts
+++ /dev/null
@@ -1,42 +0,0 @@
-import { db } from '../db/database';
-import { DayNote } from '../types';
-
-export { verifyTripAccess } from './tripAccess';
-
-export function listNotes(dayId: string | number, tripId: string | number) {
-  return db.prepare(
-    'SELECT * FROM day_notes WHERE day_id = ? AND trip_id = ? ORDER BY sort_order ASC, created_at ASC'
-  ).all(dayId, tripId);
-}
-
-export function dayExists(dayId: string | number, tripId: string | number) {
-  return db.prepare('SELECT id FROM days WHERE id = ? AND trip_id = ?').get(dayId, tripId);
-}
-
-export function createNote(dayId: string | number, tripId: string | number, text: string, time?: string, icon?: string, sort_order?: number) {
-  const result = db.prepare(
-    'INSERT INTO day_notes (day_id, trip_id, text, time, icon, sort_order) VALUES (?, ?, ?, ?, ?, ?)'
-  ).run(dayId, tripId, text.trim(), time || null, icon || '\uD83D\uDCDD', sort_order ?? 9999);
-  return db.prepare('SELECT * FROM day_notes WHERE id = ?').get(result.lastInsertRowid);
-}
-
-export function getNote(id: string | number, dayId: string | number, tripId: string | number) {
-  return db.prepare('SELECT * FROM day_notes WHERE id = ? AND day_id = ? AND trip_id = ?').get(id, dayId, tripId) as DayNote | undefined;
-}
-
-export function updateNote(id: string | number, current: DayNote, fields: { text?: string; time?: string; icon?: string; sort_order?: number }) {
-  db.prepare(
-    'UPDATE day_notes SET text = ?, time = ?, icon = ?, sort_order = ? WHERE id = ?'
-  ).run(
-    fields.text !== undefined ? fields.text.trim() : current.text,
-    fields.time !== undefined ? fields.time : current.time,
-    fields.icon !== undefined ? fields.icon : current.icon,
-    fields.sort_order !== undefined ? fields.sort_order : current.sort_order,
-    id
-  );
-  return db.prepare('SELECT * FROM day_notes WHERE id = ?').get(id);
-}
-
-export function deleteNote(id: string | number) {
-  db.prepare('DELETE FROM day_notes WHERE id = ?').run(id);
-}
diff --git a/server/tests/e2e/days.e2e.test.ts b/server/tests/e2e/days.e2e.test.ts
index e6e869c2e..cc6e83ddd 100644
--- a/server/tests/e2e/days.e2e.test.ts
+++ b/server/tests/e2e/days.e2e.test.ts
@@ -1,7 +1,8 @@
 /**
  * Days + day-notes module e2e — exercises both migrated mounts through the real
- * JwtAuthGuard against a temp SQLite db. The day/day-note services, the
- * permission check, canAccessTrip and the WebSocket broadcast are mocked.
+ * JwtAuthGuard against a temp SQLite db. The day service (still legacy), the
+ * permission check, canAccessTrip and the WebSocket broadcast are mocked; the
+ * DI-native DayNotesService runs real SQL against the temp db.
  */
 import { describe, it, expect, beforeAll, afterAll, beforeEach, vi } from 'vitest';
 import request from 'supertest';
@@ -18,6 +19,11 @@ const { db } = vi.hoisted(() => {
   tmp.exec('PRAGMA journal_mode = WAL');
   tmp.exec(`CREATE TABLE users (id INTEGER PRIMARY KEY AUTOINCREMENT, username TEXT NOT NULL,
     email TEXT NOT NULL UNIQUE, role TEXT NOT NULL DEFAULT 'user', password_version INTEGER NOT NULL DEFAULT 0);`);
+  // The tables DayNotesService really queries (real SQL, no service mock).
+  tmp.exec('CREATE TABLE days (id INTEGER PRIMARY KEY AUTOINCREMENT, trip_id INTEGER NOT NULL);');
+  tmp.exec(`CREATE TABLE day_notes (id INTEGER PRIMARY KEY AUTOINCREMENT, day_id INTEGER NOT NULL,
+    trip_id INTEGER NOT NULL, text TEXT NOT NULL, time TEXT, icon TEXT DEFAULT '📝',
+    sort_order REAL DEFAULT 0, created_at DATETIME DEFAULT CURRENT_TIMESTAMP);`);
   return { db: tmp };
 });
 
@@ -30,18 +36,14 @@ vi.mock('../../src/websocket', () => ({ broadcast: vi.fn() }));
 const { checkPermission } = vi.hoisted(() => ({ checkPermission: vi.fn() }));
 vi.mock('../../src/services/permissions', () => ({ checkPermission }));
 
-const { day, note } = vi.hoisted(() => ({
+const { day } = vi.hoisted(() => ({
   day: { listDays: vi.fn(), createDay: vi.fn(), getDay: vi.fn(), updateDay: vi.fn(), deleteDay: vi.fn() },
-  note: {
-    verifyTripAccess: vi.fn(), listNotes: vi.fn(), dayExists: vi.fn(), createNote: vi.fn(),
-    getNote: vi.fn(), updateNote: vi.fn(), deleteNote: vi.fn(),
-  },
 }));
 vi.mock('../../src/services/dayService', () => day);
-vi.mock('../../src/services/dayNoteService', () => note);
 
 import { DaysModule } from '../../src/nest/days/days.module';
 import { TrekExceptionFilter } from '../../src/nest/common/trek-exception.filter';
+import { ZodValidationPipe } from '../../src/nest/common/zod-validation.pipe';
 
 describe('Days + day-notes e2e (real auth guard + temp SQLite)', () => {
   let server: Server;
@@ -51,6 +53,7 @@ describe('Days + day-notes e2e (real auth guard + temp SQLite)', () => {
     const moduleRef = await Test.createTestingModule({ imports: [DatabaseModule, DaysModule] }).compile();
     const nest = moduleRef.createNestApplication();
     nest.use(cookieParser());
+    nest.useGlobalPipes(new ZodValidationPipe());
     nest.useGlobalFilters(new TrekExceptionFilter());
     await nest.init();
     return nest;
@@ -58,18 +61,16 @@ describe('Days + day-notes e2e (real auth guard + temp SQLite)', () => {
 
   beforeAll(async () => {
     seedUser(db as never, { id: 1 });
+    db.prepare('INSERT INTO days (id, trip_id) VALUES (3, 5)').run();
     app = await build();
     server = app.getHttpServer();
     day.listDays.mockReturnValue({ days: [{ id: 1 }] });
     day.createDay.mockReturnValue({ id: 9 });
-    note.listNotes.mockReturnValue([{ id: 1 }]);
-    note.dayExists.mockReturnValue(true);
-    note.createNote.mockReturnValue({ id: 7 });
   });
 
   beforeEach(() => {
+    db.prepare('DELETE FROM day_notes').run();
     canAccessTrip.mockReturnValue({ id: 5, user_id: 1 });
-    note.verifyTripAccess.mockReturnValue({ id: 5, user_id: 1 });
     checkPermission.mockReturnValue(true);
   });
 
@@ -97,13 +98,29 @@ describe('Days + day-notes e2e (real auth guard + temp SQLite)', () => {
     expect(miss.body).toEqual({ error: 'Trip not found' });
   });
 
-  it('201 create note, 400 on over-long text (before access)', async () => {
-    const ok = await request(server).post('/api/trips/5/days/3/notes').set('Cookie', sessionCookie(1)).send({ text: 'Lunch' });
+  it('201 create note (real insert: trim, empty-string coercions), 400 on over-long text (before access)', async () => {
+    const ok = await request(server).post('/api/trips/5/days/3/notes').set('Cookie', sessionCookie(1))
+      .send({ text: '  Lunch  ', time: '', icon: '', sort_order: 0 });
     expect(ok.status).toBe(201);
-    expect(ok.body).toEqual({ note: { id: 7 } });
+    expect(ok.body.note).toMatchObject({ day_id: 3, trip_id: 5, text: 'Lunch', time: null, icon: '📝', sort_order: 0 });
+    const row = db.prepare('SELECT * FROM day_notes WHERE id = ?').get(ok.body.note.id);
+    expect(row).toMatchObject({ text: 'Lunch', time: null, icon: '📝', sort_order: 0 });
     const long = await request(server).post('/api/trips/5/days/3/notes').set('Cookie', sessionCookie(1)).send({ text: 'x'.repeat(501) });
     expect(long.status).toBe(400);
-    expect(long.body).toEqual({ error: 'text must be 500 characters or less' });
+    expect(long.body.error).toContain('text');
+  });
+
+  it('201 create accepts null time/icon (moveDayNote re-sends the nullable entity fields)', async () => {
+    const res = await request(server).post('/api/trips/5/days/3/notes').set('Cookie', sessionCookie(1))
+      .send({ text: 'Moved', time: null, icon: null, sort_order: 3 });
+    expect(res.status).toBe(201);
+    expect(res.body.note).toMatchObject({ text: 'Moved', time: null, icon: '📝', sort_order: 3 });
+  });
+
+  it('404 Day not found when the day is not on the trip', async () => {
+    const res = await request(server).post('/api/trips/5/days/99/notes').set('Cookie', sessionCookie(1)).send({ text: 'Lunch' });
+    expect(res.status).toBe(404);
+    expect(res.body).toEqual({ error: 'Day not found' });
   });
 
   it('400 note without text', async () => {
@@ -111,4 +128,26 @@ describe('Days + day-notes e2e (real auth guard + temp SQLite)', () => {
     expect(res.status).toBe(400);
     expect(res.body).toEqual({ error: 'Text required' });
   });
+
+  it('200 update note merges omitted fields from the current row', async () => {
+    const created = await request(server).post('/api/trips/5/days/3/notes').set('Cookie', sessionCookie(1))
+      .send({ text: 'Lunch', time: '12:00' });
+    const id = created.body.note.id;
+    const res = await request(server).put(`/api/trips/5/days/3/notes/${id}`).set('Cookie', sessionCookie(1))
+      .send({ icon: '🍜' });
+    expect(res.status).toBe(200);
+    expect(res.body.note).toMatchObject({ id, text: 'Lunch', time: '12:00', icon: '🍜' });
+    const miss = await request(server).put('/api/trips/5/days/3/notes/9999').set('Cookie', sessionCookie(1)).send({ text: 'x' });
+    expect(miss.status).toBe(404);
+    expect(miss.body).toEqual({ error: 'Note not found' });
+  });
+
+  it('200 delete note removes the row', async () => {
+    const created = await request(server).post('/api/trips/5/days/3/notes').set('Cookie', sessionCookie(1)).send({ text: 'Lunch' });
+    const id = created.body.note.id;
+    const res = await request(server).delete(`/api/trips/5/days/3/notes/${id}`).set('Cookie', sessionCookie(1));
+    expect(res.status).toBe(200);
+    expect(res.body).toEqual({ success: true });
+    expect(db.prepare('SELECT * FROM day_notes WHERE id = ?').get(id)).toBeUndefined();
+  });
 });
diff --git a/server/tests/helpers/factories.ts b/server/tests/helpers/factories.ts
index a4bd57af2..7acb2c521 100644
--- a/server/tests/helpers/factories.ts
+++ b/server/tests/helpers/factories.ts
@@ -279,11 +279,11 @@ export function createDayNote(
   db: Database.Database,
   dayId: number,
   tripId: number,
-  overrides: Partial<{ text: string; time: string; icon: string }> = {}
+  overrides: Partial<{ text: string; time: string; icon: string; sort_order: number }> = {}
 ): TestDayNote {
   const result = db.prepare(
-    'INSERT INTO day_notes (day_id, trip_id, text, time, icon, sort_order) VALUES (?, ?, ?, ?, ?, 9999)'
-  ).run(dayId, tripId, overrides.text ?? 'Test note', overrides.time ?? null, overrides.icon ?? '📝');
+    'INSERT INTO day_notes (day_id, trip_id, text, time, icon, sort_order) VALUES (?, ?, ?, ?, ?, ?)'
+  ).run(dayId, tripId, overrides.text ?? 'Test note', overrides.time ?? null, overrides.icon ?? '📝', overrides.sort_order ?? 9999);
   return db.prepare('SELECT * FROM day_notes WHERE id = ?').get(result.lastInsertRowid) as TestDayNote;
 }
 
diff --git a/server/tests/helpers/mcp-test-controllers.ts b/server/tests/helpers/mcp-test-controllers.ts
index 4bb27f6bf..343b374d8 100644
--- a/server/tests/helpers/mcp-test-controllers.ts
+++ b/server/tests/helpers/mcp-test-controllers.ts
@@ -4,6 +4,8 @@ import { trekMcpAccessPolicy } from '../../src/mcp/nest-mcp-policy';
 import { CategoriesMcp } from '../../src/nest/categories/categories.mcp';
 import { CategoriesService } from '../../src/nest/categories/categories.service';
 import { DatabaseService } from '../../src/nest/database/database.service';
+import { DayNotesMcp } from '../../src/nest/days/day-notes.mcp';
+import { DayNotesService } from '../../src/nest/days/day-notes.service';
 import { PackingMcp } from '../../src/nest/packing/packing.mcp';
 import { PackingService } from '../../src/nest/packing/packing.service';
 import { TagsMcp } from '../../src/nest/tags/tags.mcp';
@@ -26,6 +28,7 @@ export function createMcpTestRegistry(): McpRegistry {
       new CategoriesMcp(new CategoriesService(dbService)),
       new TodoMcp(new TodoService(dbService)),
       new PackingMcp(new PackingService(dbService)),
+      new DayNotesMcp(new DayNotesService(dbService)),
     ],
     { accessPolicy: trekMcpAccessPolicy },
   );
diff --git a/server/tests/helpers/plugin-host.ts b/server/tests/helpers/plugin-host.ts
index a5d47ecc2..1a6e6ffc7 100644
--- a/server/tests/helpers/plugin-host.ts
+++ b/server/tests/helpers/plugin-host.ts
@@ -9,6 +9,7 @@ import { TagsService } from '../../src/nest/tags/tags.service';
 import { CategoriesService } from '../../src/nest/categories/categories.service';
 import { TodoService } from '../../src/nest/todo/todo.service';
 import { PackingService } from '../../src/nest/packing/packing.service';
+import { DayNotesService } from '../../src/nest/days/day-notes.service';
 
 /**
  * Hand-wired counterpart of the PluginsModule DI graph for no-Nest tests
@@ -25,6 +26,7 @@ export function createHostDepsFactory(dbs: DatabaseService): PluginHostDepsFacto
     new TodoService(dbs),
     new PackingService(dbs),
     new PluginOAuthService(dbs),
+    new DayNotesService(dbs),
   );
 }
 
diff --git a/server/tests/unit/mcp/resources.test.ts b/server/tests/unit/mcp/resources.test.ts
index 67a3ed30f..90d14cf57 100644
--- a/server/tests/unit/mcp/resources.test.ts
+++ b/server/tests/unit/mcp/resources.test.ts
@@ -1,10 +1,12 @@
 /**
  * Unit tests for MCP resources (resources.ts).
- * Tests all 10 legacy-registrar resources via InMemoryTransport + Client
+ * Tests all 9 legacy-registrar resources via InMemoryTransport + Client
  * (trek://categories moved to the DI-discovered CategoriesMcp — see
  * tools-categories.test.ts; trek://trips/{tripId}/todos moved to TodoMcp —
  * see tools-todos.test.ts; trek://trips/{tripId}/packing and .../packing/bags
- * moved to PackingMcp — see tools-packing.test.ts).
+ * moved to PackingMcp — see tools-packing.test.ts;
+ * trek://trips/{tripId}/days/{dayId}/notes moved to DayNotesMcp — see
+ * tools-notes.test.ts).
  */
 import { describe, it, expect, vi, beforeAll, beforeEach, afterAll, afterEach } from 'vitest';
 
@@ -43,7 +45,7 @@ vi.mock('../../../src/websocket', () => ({ broadcast: vi.fn() }));
 import { createTables } from '../../../src/db/schema';
 import { runMigrations } from '../../../src/db/migrations';
 import { resetTestDb } from '../../helpers/test-db';
-import { createUser, createTrip, createDay, createPlace, addTripMember, createBudgetItem, createReservation, createDayNote, createCollabNote, createBucketListItem, createVisitedCountry, createDayAssignment, createDayAccommodation } from '../../helpers/factories';
+import { createUser, createTrip, createDay, createPlace, addTripMember, createBudgetItem, createReservation, createCollabNote, createBucketListItem, createVisitedCountry, createDayAssignment, createDayAccommodation } from '../../helpers/factories';
 import { createMcpHarness, parseResourceResult, type McpHarness } from '../../helpers/mcp-harness';
 
 beforeAll(() => {
@@ -268,45 +270,8 @@ describe('Resource: trek://trips/{tripId}/reservations', () => {
   });
 });
 
-describe('Resource: trek://trips/{tripId}/days/{dayId}/notes', () => {
-  it('returns notes for a specific day', async () => {
-    const { user } = createUser(testDb);
-    const trip = createTrip(testDb, user.id);
-    const day = createDay(testDb, trip.id);
-    createDayNote(testDb, day.id, trip.id, { text: 'Check in at noon' });
-
-    await withHarness(user.id, async (harness) => {
-      const result = await harness.client.readResource({ uri: `trek://trips/${trip.id}/days/${day.id}/notes` });
-      const notes = parseResourceResult(result) as any[];
-      expect(notes).toHaveLength(1);
-      expect(notes[0].text).toBe('Check in at noon');
-    });
-  });
-
-  it('returns access denied for unauthorized trip', async () => {
-    const { user } = createUser(testDb);
-    const { user: other } = createUser(testDb);
-    const trip = createTrip(testDb, other.id);
-    const day = createDay(testDb, trip.id);
-
-    await withHarness(user.id, async (harness) => {
-      const result = await harness.client.readResource({ uri: `trek://trips/${trip.id}/days/${day.id}/notes` });
-      const data = parseResourceResult(result) as any;
-      expect(data.error).toBeTruthy();
-    });
-  });
-
-  it('returns access denied for invalid dayId', async () => {
-    const { user } = createUser(testDb);
-    const trip = createTrip(testDb, user.id);
-
-    await withHarness(user.id, async (harness) => {
-      const result = await harness.client.readResource({ uri: `trek://trips/${trip.id}/days/abc/notes` });
-      const data = parseResourceResult(result) as any;
-      expect(data.error).toBeTruthy();
-    });
-  });
-});
+// The trek://trips/{tripId}/days/{dayId}/notes resource moved to the
+// DI-discovered DayNotesMcp — see tools-notes.test.ts.
 
 describe('Resource: trek://trips/{tripId}/accommodations', () => {
   it('returns accommodations for a trip', async () => {
diff --git a/server/tests/unit/mcp/tools-notes.test.ts b/server/tests/unit/mcp/tools-notes.test.ts
index a3927b4ea..fca70ae2b 100644
--- a/server/tests/unit/mcp/tools-notes.test.ts
+++ b/server/tests/unit/mcp/tools-notes.test.ts
@@ -1,6 +1,9 @@
 /**
- * Unit tests for MCP note tools: create_day_note, update_day_note, delete_day_note,
- * create_collab_note, update_collab_note, delete_collab_note.
+ * Unit tests for MCP note tools: create_day_note, update_day_note, delete_day_note
+ * (DayNotesMcp, DI-discovered — attached via the nest-mcp registry inside
+ * registerTools, so every harness here keeps withTools on) and
+ * create_collab_note, update_collab_note, delete_collab_note (still on the
+ * legacy registrar).
  */
 import { describe, it, expect, vi, beforeAll, beforeEach, afterAll } from 'vitest';
 
@@ -44,7 +47,7 @@ import { createTables } from '../../../src/db/schema';
 import { runMigrations } from '../../../src/db/migrations';
 import { resetTestDb } from '../../helpers/test-db';
 import { createUser, createTrip, createDay, createDayNote, createCollabNote } from '../../helpers/factories';
-import { createMcpHarness, parseToolResult, type McpHarness } from '../../helpers/mcp-harness';
+import { createMcpHarness, parseToolResult, parseResourceResult, type McpHarness } from '../../helpers/mcp-harness';
 
 beforeAll(() => {
   createTables(testDb);
@@ -258,6 +261,84 @@ describe('Tool: delete_day_note', () => {
   });
 });
 
+// ---------------------------------------------------------------------------
+// Scope gating (trips write, registration-time — the legacy registerDayTools
+// whole-registrar `canWrite(scopes, 'trips')` early return, now the
+// declarative access marker on every DayNotesMcp tool)
+// ---------------------------------------------------------------------------
+
+describe('Day-note tools — scope gating', () => {
+  const WRITE_TOOLS = ['create_day_note', 'update_day_note', 'delete_day_note'];
+
+  async function listToolNames(userId: number, scopes: string[] | null): Promise<string[]> {
+    const h = await createMcpHarness({ userId, withResources: false, scopes });
+    try {
+      return (await h.client.listTools()).tools.map((t) => t.name);
+    } finally {
+      await h.cleanup();
+    }
+  }
+
+  it('registers all three tools with null scopes (full access)', async () => {
+    const { user } = createUser(testDb);
+    const names = await listToolNames(user.id, null);
+    for (const tool of WRITE_TOOLS) expect(names).toContain(tool);
+  });
+
+  it('registers no day-note tools with trips:read only (all three are writes)', async () => {
+    const { user } = createUser(testDb);
+    const names = await listToolNames(user.id, ['trips:read']);
+    for (const tool of WRITE_TOOLS) expect(names).not.toContain(tool);
+  });
+
+  it('registers no day-note tools for an unrelated scope', async () => {
+    const { user } = createUser(testDb);
+    const names = await listToolNames(user.id, ['budget:read']);
+    for (const tool of WRITE_TOOLS) expect(names).not.toContain(tool);
+  });
+});
+
+// ---------------------------------------------------------------------------
+// trek://trips/{tripId}/days/{dayId}/notes resource (moved from the legacy
+// registerResources to DayNotesMcp)
+// ---------------------------------------------------------------------------
+
+describe('Resource: trek://trips/{tripId}/days/{dayId}/notes', () => {
+  it('returns the day notes ordered by sort_order', async () => {
+    const { user } = createUser(testDb);
+    const trip = createTrip(testDb, user.id);
+    const day = createDay(testDb, trip.id);
+    createDayNote(testDb, day.id, trip.id, { text: 'Second', sort_order: 5 });
+    createDayNote(testDb, day.id, trip.id, { text: 'First', sort_order: 1 });
+    await withHarness(user.id, async (h) => {
+      const result = await h.client.readResource({ uri: `trek://trips/${trip.id}/days/${day.id}/notes` });
+      const notes = parseResourceResult(result) as { text: string }[];
+      expect(notes).toHaveLength(2);
+      expect(notes[0].text).toBe('First');
+      expect(notes[1].text).toBe('Second');
+    });
+  });
+
+  it('returns the access-denied payload for a non-member', async () => {
+    const { user } = createUser(testDb);
+    const { user: other } = createUser(testDb);
+    const trip = createTrip(testDb, other.id);
+    const day = createDay(testDb, trip.id);
+    await withHarness(user.id, async (h) => {
+      const result = await h.client.readResource({ uri: `trek://trips/${trip.id}/days/${day.id}/notes` });
+      expect(parseResourceResult(result)).toEqual({ error: 'Trip not found or access denied' });
+    });
+  });
+
+  it('returns the access-denied payload for a malformed id', async () => {
+    const { user } = createUser(testDb);
+    await withHarness(user.id, async (h) => {
+      const result = await h.client.readResource({ uri: 'trek://trips/1/days/not-a-number/notes' });
+      expect(parseResourceResult(result)).toEqual({ error: 'Trip not found or access denied' });
+    });
+  });
+});
+
 // ---------------------------------------------------------------------------
 // create_collab_note
 // ---------------------------------------------------------------------------
diff --git a/server/tests/unit/nest/day-notes.service.test.ts b/server/tests/unit/nest/day-notes.service.test.ts
new file mode 100644
index 000000000..bf9a3f01c
--- /dev/null
+++ b/server/tests/unit/nest/day-notes.service.test.ts
@@ -0,0 +1,223 @@
+/**
+ * Unit tests for the DI-native DayNotesService — DAYNOTE-SVC-001 through
+ * DAYNOTE-SVC-016. The legacy dayNoteService had no dedicated suite (it was
+ * only covered transitively), so these cases are authored fresh with the DI
+ * move to pin the relocated SQL and its quirks (trim-on-write, `||` empty-
+ * string coercions vs the `??` sort_order default, JS-side update merge,
+ * post-write re-selects). Uses a real in-memory SQLite DB so SQL logic is
+ * exercised faithfully.
+ */
+import { describe, it, expect, vi, beforeAll, beforeEach, afterAll } from 'vitest';
+
+// ── DB setup ──────────────────────────────────────────────────────────────────
+
+const { testDb, dbMock } = vi.hoisted(() => {
+  const Database = require('better-sqlite3');
+  const db = new Database(':memory:');
+  db.exec('PRAGMA journal_mode = WAL');
+  db.exec('PRAGMA foreign_keys = ON');
+  db.exec('PRAGMA busy_timeout = 5000');
+  const mock = {
+    db,
+    closeDb: () => {},
+    reinitialize: () => {},
+    getPlaceWithTags: () => null,
+    canAccessTrip: (tripId: number | string, userId: number) =>
+      db.prepare(`
+        SELECT t.id, t.user_id FROM trips t
+        LEFT JOIN trip_members m ON m.trip_id = t.id AND m.user_id = ?
+        WHERE t.id = ? AND (t.user_id = ? OR m.user_id IS NOT NULL)
+      `).get(userId, tripId, userId),
+    isOwner: (tripId: number | string, userId: number) =>
+      !!db.prepare('SELECT id FROM trips WHERE id = ? AND user_id = ?').get(tripId, userId),
+  };
+  return { testDb: db, dbMock: mock };
+});
+
+vi.mock('../../../src/db/database', () => dbMock);
+vi.mock('../../../src/config', () => ({
+  JWT_SECRET: 'test-secret',
+  ENCRYPTION_KEY: 'a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6a7b8c9d0e1f2a3b4c5d6a7b8c9d0e1f2',
+  updateJwtSecret: () => {},
+}));
+vi.mock('../../../src/websocket', () => ({ broadcast: vi.fn() }));
+
+import { createTables } from '../../../src/db/schema';
+import { runMigrations } from '../../../src/db/migrations';
+import { resetTestDb } from '../../helpers/test-db';
+import { createUser, createTrip, createDay, addTripMember } from '../../helpers/factories';
+import { DatabaseService } from '../../../src/nest/database/database.service';
+import { DayNotesService } from '../../../src/nest/days/day-notes.service';
+import type { DayNote } from '../../../src/types';
+
+const svc = new DayNotesService(new DatabaseService(testDb));
+
+beforeAll(() => {
+  createTables(testDb);
+  runMigrations(testDb);
+});
+
+beforeEach(() => {
+  resetTestDb(testDb);
+});
+
+afterAll(() => {
+  testDb.close();
+});
+
+function seedTripAndDay() {
+  const { user } = createUser(testDb);
+  const trip = createTrip(testDb, user.id);
+  const day = createDay(testDb, trip.id);
+  return { user, trip, day };
+}
+
+// ── verifyTripAccess ──────────────────────────────────────────────────────────
+
+describe('verifyTripAccess', () => {
+  it('DAYNOTE-SVC-001: returns trip for owner', () => {
+    const { user } = createUser(testDb);
+    const trip = createTrip(testDb, user.id);
+    const result = svc.verifyTripAccess(trip.id, user.id);
+    expect(result).toBeDefined();
+    expect(result?.id).toBe(trip.id);
+  });
+
+  it('DAYNOTE-SVC-002: returns nothing for non-member', () => {
+    const { user: owner } = createUser(testDb);
+    const { user: stranger } = createUser(testDb);
+    const trip = createTrip(testDb, owner.id);
+    expect(svc.verifyTripAccess(trip.id, stranger.id)).toBeFalsy();
+  });
+
+  it('DAYNOTE-SVC-003: returns trip for member', () => {
+    const { user: owner } = createUser(testDb);
+    const { user: member } = createUser(testDb);
+    const trip = createTrip(testDb, owner.id);
+    addTripMember(testDb, trip.id, member.id);
+    expect(svc.verifyTripAccess(trip.id, member.id)).toBeDefined();
+  });
+});
+
+// ── dayExists ─────────────────────────────────────────────────────────────────
+
+describe('dayExists', () => {
+  it('DAYNOTE-SVC-004: truthy only when the day belongs to the trip', () => {
+    const { trip, day } = seedTripAndDay();
+    const { user: other } = createUser(testDb);
+    const otherTrip = createTrip(testDb, other.id);
+    expect(svc.dayExists(day.id, trip.id)).toBeTruthy();
+    expect(svc.dayExists(day.id, otherTrip.id)).toBeFalsy();
+    expect(svc.dayExists(9999, trip.id)).toBeFalsy();
+  });
+});
+
+// ── create ────────────────────────────────────────────────────────────────────
+
+describe('create', () => {
+  it('DAYNOTE-SVC-005: inserts and returns the re-selected row', () => {
+    const { trip, day } = seedTripAndDay();
+    const note = svc.create(day.id, trip.id, 'Lunch', '12:00', '🍜', 2) as DayNote;
+    expect(note).toMatchObject({ day_id: day.id, trip_id: trip.id, text: 'Lunch', time: '12:00', icon: '🍜', sort_order: 2 });
+    expect(note.id).toBeGreaterThan(0);
+    const row = testDb.prepare('SELECT * FROM day_notes WHERE id = ?').get(note.id);
+    expect(row).toEqual(note);
+  });
+
+  it('DAYNOTE-SVC-006: trims the text on insert', () => {
+    const { trip, day } = seedTripAndDay();
+    const note = svc.create(day.id, trip.id, '  Lunch  ') as DayNote;
+    expect(note.text).toBe('Lunch');
+  });
+
+  it('DAYNOTE-SVC-007: empty-string time coerces to NULL (`||`, not `??`)', () => {
+    const { trip, day } = seedTripAndDay();
+    expect((svc.create(day.id, trip.id, 'a', '') as DayNote).time).toBeNull();
+    expect((svc.create(day.id, trip.id, 'b', undefined) as DayNote).time).toBeNull();
+    expect((svc.create(day.id, trip.id, 'c', null) as DayNote).time).toBeNull();
+  });
+
+  it('DAYNOTE-SVC-008: empty/absent icon falls back to 📝 (`||`, not `??`)', () => {
+    const { trip, day } = seedTripAndDay();
+    expect((svc.create(day.id, trip.id, 'a', undefined, '') as DayNote).icon).toBe('📝');
+    expect((svc.create(day.id, trip.id, 'b') as DayNote).icon).toBe('📝');
+    expect((svc.create(day.id, trip.id, 'c', undefined, null) as DayNote).icon).toBe('📝');
+  });
+
+  it('DAYNOTE-SVC-009: sort_order 0 is preserved, only undefined defaults to 9999 (`??`)', () => {
+    const { trip, day } = seedTripAndDay();
+    expect((svc.create(day.id, trip.id, 'a', undefined, undefined, 0) as DayNote).sort_order).toBe(0);
+    expect((svc.create(day.id, trip.id, 'b') as DayNote).sort_order).toBe(9999);
+  });
+});
+
+// ── list ──────────────────────────────────────────────────────────────────────
+
+describe('list', () => {
+  it('DAYNOTE-SVC-010: returns [] for a day without notes', () => {
+    const { trip, day } = seedTripAndDay();
+    expect(svc.list(day.id, trip.id)).toEqual([]);
+  });
+
+  it('DAYNOTE-SVC-011: orders by sort_order then created_at and scopes to day+trip', () => {
+    const { trip, day } = seedTripAndDay();
+    const otherDay = createDay(testDb, trip.id);
+    const second = svc.create(day.id, trip.id, 'second', undefined, undefined, 5) as DayNote;
+    const first = svc.create(day.id, trip.id, 'first', undefined, undefined, 1) as DayNote;
+    svc.create(otherDay.id, trip.id, 'elsewhere');
+    const notes = svc.list(day.id, trip.id) as DayNote[];
+    expect(notes.map((n) => n.id)).toEqual([first.id, second.id]);
+  });
+});
+
+// ── getNote ───────────────────────────────────────────────────────────────────
+
+describe('getNote', () => {
+  it('DAYNOTE-SVC-012: returns the note only under its own day and trip', () => {
+    const { trip, day } = seedTripAndDay();
+    const otherDay = createDay(testDb, trip.id);
+    const note = svc.create(day.id, trip.id, 'Lunch') as DayNote;
+    expect(svc.getNote(note.id, day.id, trip.id)).toEqual(note);
+    expect(svc.getNote(note.id, otherDay.id, trip.id)).toBeUndefined();
+    expect(svc.getNote(note.id, day.id, trip.id + 1)).toBeUndefined();
+  });
+});
+
+// ── update ────────────────────────────────────────────────────────────────────
+
+describe('update', () => {
+  it('DAYNOTE-SVC-013: merges omitted fields from the current row (JS-side, full-row UPDATE)', () => {
+    const { trip, day } = seedTripAndDay();
+    const note = svc.create(day.id, trip.id, 'Lunch', '12:00', '🍜', 2) as DayNote;
+    const updated = svc.update(note.id, note, { icon: '🍣' }) as DayNote;
+    expect(updated).toMatchObject({ id: note.id, text: 'Lunch', time: '12:00', icon: '🍣', sort_order: 2 });
+  });
+
+  it('DAYNOTE-SVC-014: explicit null time clears it, undefined keeps it', () => {
+    const { trip, day } = seedTripAndDay();
+    const note = svc.create(day.id, trip.id, 'Lunch', '12:00') as DayNote;
+    const kept = svc.update(note.id, note, { text: 'Lunch!' }) as DayNote;
+    expect(kept.time).toBe('12:00');
+    const cleared = svc.update(note.id, kept, { time: null }) as DayNote;
+    expect(cleared.time).toBeNull();
+  });
+
+  it('DAYNOTE-SVC-015: trims only the new text and preserves sort_order 0 writes', () => {
+    const { trip, day } = seedTripAndDay();
+    const note = svc.create(day.id, trip.id, 'Lunch', undefined, undefined, 5) as DayNote;
+    const updated = svc.update(note.id, note, { text: '  Dinner  ', sort_order: 0 }) as DayNote;
+    expect(updated.text).toBe('Dinner');
+    expect(updated.sort_order).toBe(0);
+  });
+});
+
+// ── remove ────────────────────────────────────────────────────────────────────
+
+describe('remove', () => {
+  it('DAYNOTE-SVC-016: deletes by bare id (trip-scoping is the caller getNote)', () => {
+    const { trip, day } = seedTripAndDay();
+    const note = svc.create(day.id, trip.id, 'Lunch') as DayNote;
+    svc.remove(note.id);
+    expect(testDb.prepare('SELECT * FROM day_notes WHERE id = ?').get(note.id)).toBeUndefined();
+  });
+});
diff --git a/server/tests/unit/plugins/plugin-host-deps.factory.test.ts b/server/tests/unit/plugins/plugin-host-deps.factory.test.ts
index e8c79a975..d05505940 100644
--- a/server/tests/unit/plugins/plugin-host-deps.factory.test.ts
+++ b/server/tests/unit/plugins/plugin-host-deps.factory.test.ts
@@ -3,9 +3,9 @@
  * capability host to the real privileged modules (#plugins, M1). Verifies the
  * per-plugin data db is cached, a granted db:own call works through the wired
  * host, and trip broadcasts are force-namespaced to plugin:{id}:{event}.
- * DI-native domains (budget/reservations/tags/categories/todo/packing/oauth)
- * are constructor-injected stubs; legacy services/* domains stay path-mocked
- * until their own DI migration lands.
+ * DI-native domains (budget/reservations/tags/categories/todo/packing/
+ * day-notes/oauth) are constructor-injected stubs; legacy services/* domains
+ * stay path-mocked until their own DI migration lands.
  */
 import { describe, it, expect, beforeAll, beforeEach, afterAll, vi } from 'vitest';
 import fs from 'node:fs';
@@ -273,14 +273,15 @@ vi.mock('../../../src/services/collectionsService', () => {
     deletePlace: vi.fn((_uid: number, placeId: number) => { if (placeId === 404) httpError(404, 'Collection not found'); }),
   };
 });
-vi.mock('../../../src/services/dayNoteService', () => ({
-  listNotes: vi.fn((dayId: number, tripId: number) => [{ id: 1, day_id: dayId, trip_id: tripId }]),
-  createNote: vi.fn((dayId: number, _tripId: number, text: string) => ({ id: 50, day_id: dayId, text })),
+// Day notes are a constructor-injected stub (same behaviors as the old path mock).
+const dayNotesStub = {
+  list: vi.fn((dayId: number, tripId: number) => [{ id: 1, day_id: dayId, trip_id: tripId }]),
+  create: vi.fn((dayId: number, _tripId: number, text: string) => ({ id: 50, day_id: dayId, text })),
   getNote: vi.fn((id: number) => (id === 99 ? undefined : { id, text: 'Old' })),
-  updateNote: vi.fn((id: number, _current: unknown, fields: Record<string, unknown>) => ({ id, ...fields })),
-  deleteNote: vi.fn(),
+  update: vi.fn((id: number, _current: unknown, fields: Record<string, unknown>) => ({ id, ...fields })),
+  remove: vi.fn(),
   dayExists: vi.fn((dayId: number) => dayId === 3),
-}));
+} as unknown as DayNotesService;
 
 import { PluginHostDepsFactory, type PluginCallRouter } from '../../../src/nest/plugins/host/plugin-host-deps.factory';
 import { getPluginDataDb, closePluginDataDb } from '../../../src/nest/plugins/host/plugin-host-state';
@@ -291,12 +292,13 @@ import type { TagsService } from '../../../src/nest/tags/tags.service';
 import type { CategoriesService } from '../../../src/nest/categories/categories.service';
 import type { TodoService } from '../../../src/nest/todo/todo.service';
 import type { PackingService } from '../../../src/nest/packing/packing.service';
+import type { DayNotesService } from '../../../src/nest/days/day-notes.service';
 import type { PluginOAuthService } from '../../../src/nest/plugins/plugin-oauth.service';
 
 // The factory under test, wired exactly like PluginsModule does — but with the
 // DI-native domain services replaced by the stubs above. The shim keeps the
 // ~45 historical call sites unchanged and supplies a default no-op router.
-const factory = new PluginHostDepsFactory(budgetStub, reservationsStub, tagsStub, categoriesStub, todoStub, packingStub, oauthStub);
+const factory = new PluginHostDepsFactory(budgetStub, reservationsStub, tagsStub, categoriesStub, todoStub, packingStub, oauthStub, dayNotesStub);
 const stubRouter: PluginCallRouter = { callPlugin: async () => undefined, emitPluginEvent: () => {} };
 const createRealRpcHost = (id: string, granted: ReadonlySet<string>, router: PluginCallRouter = stubRouter) => factory.create(id, granted, router);