create issues fix

issue observers

Наблюдатели задачи видят её и комментируют, но не редактируют.

- таблица issue_observer, наблюдатели — часть сущности Issue
- видимость: reporter, assignee или наблюдатель (задачи, история, SSE)
- правка/удаление задачи и вложений — только reporter/assignee (403 наблюдателю)
- observers в create/update, DELETE /issues/:id/observers/me, фильтр role
- история изменений и уведомления новым наблюдателям

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

prisma/migrations/20261025190802_issue_observer/migration.sql

@@ -0,0 +1,17 @@
+-- CreateTable
+CREATE TABLE "issue_observer" (
+    "issueId" INTEGER NOT NULL,
+    "userId" TEXT NOT NULL,
+    "createdAt" TIMESTAMPTZ(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+
+    CONSTRAINT "issue_observer_pkey" PRIMARY KEY ("issueId","userId")
+);
+
+-- CreateIndex
+CREATE INDEX "issue_observer_userId_idx" ON "issue_observer"("userId");
+
+-- AddForeignKey
+ALTER TABLE "issue_observer" ADD CONSTRAINT "issue_observer_issueId_fkey" FOREIGN KEY ("issueId") REFERENCES "issue"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "issue_observer" ADD CONSTRAINT "issue_observer_userId_fkey" FOREIGN KEY ("userId") REFERENCES "user"("id") ON DELETE CASCADE ON UPDATE CASCADE;

prisma/migrations/20261025192028_project_member_role/migration.sql

@@ -0,0 +1,5 @@
+-- CreateEnum
+CREATE TYPE "ProjectRole" AS ENUM ('MEMBER', 'OBSERVER');
+
+-- AlterTable
+ALTER TABLE "project_member" ADD COLUMN     "role" "ProjectRole" NOT NULL DEFAULT 'MEMBER';

prisma/schema.prisma

@@ -31,6 +31,7 @@ model User {
   comments                 Comment[]
   uploadedFiles            File[]                    @relation(name: "fileUploader")
   issueChanges             IssueChange[]
+  observedIssues           IssueObserver[]
 
   @@unique([email])
   @@map("user")
@@ -103,6 +104,7 @@ model Issue {
   comments    Comment[]
   attachments IssueAttachment[]
   changes     IssueChange[]
+  observers   IssueObserver[]
   createdAt   DateTime          @default(now()) @db.Timestamptz(3)
   updatedAt   DateTime          @updatedAt @db.Timestamptz(3)
 
@@ -118,6 +120,21 @@ model Issue {
   @@map("issue")
 }
 
+/// Наблюдатель задачи: видит её и может комментировать, но не редактировать.
+/// Редактируют задачу только reporter и assignee.
+model IssueObserver {
+  issueId   Int
+  userId    String
+  createdAt DateTime @default(now()) @db.Timestamptz(3)
+
+  issue Issue @relation(fields: [issueId], references: [id], onDelete: Cascade)
+  user  User  @relation(fields: [userId], references: [id], onDelete: Cascade)
+
+  @@id([issueId, userId])
+  @@index([userId])
+  @@map("issue_observer")
+}
+
 model Project {
   id        String          @id @default(uuid(7))
   name      String
@@ -135,10 +152,18 @@ model Project {
   @@map("project")
 }
 
+/// MEMBER создаёт задачи в проекте; OBSERVER только видит проект —
+/// он наблюдает за отдельными задачами (IssueObserver).
+enum ProjectRole {
+  MEMBER
+  OBSERVER
+}
+
 model ProjectMember {
   id        String      @id @default(uuid(7))
   projectId String
   userId    String
+  role      ProjectRole @default(MEMBER)
   createdAt DateTime    @default(now()) @db.Timestamptz(3)
 
   project Project @relation(fields: [projectId], references: [id], onDelete: Cascade)

src/modules/history/application/dto/issue-history.dto.ts

@@ -5,7 +5,7 @@ export class IssueFieldChangeDto {
   field: IssueChangeField;
   oldValue: string | null;
   newValue: string | null;
-  /** Только для field = assignee: пользователи из oldValue/newValue (null — не назначен или удалён) */
+  /** Только для field = assignee/observer: пользователи из oldValue/newValue (null — не назначен или удалён) */
   oldUser?: UserDto | null;
   newUser?: UserDto | null;
 }

src/modules/history/application/use-cases/get-daily-issue-stats/get-daily-issue-stats.use-case.ts

@@ -10,7 +10,7 @@ import { GetDailyIssueStatsQuery } from './get-daily-issue-stats.query.js';
 
 /**
  * Статистика задач по дням, считается по истории изменений (issue_change).
- * Видимость — как у списка задач: только задачи, где пользователь reporter/assignee.
+ * Видимость — как у списка задач: только задачи, где пользователь reporter/assignee/наблюдатель.
  */
 @Injectable()
 export class GetDailyIssueStatsUseCase {

src/modules/history/application/use-cases/get-issue-history/get-issue-history.use-case.ts

@@ -14,6 +14,10 @@ import {
 } from '../../../domain/repositories/issue-history.repository.interface.js';
 import { IssueFieldChangeDto, IssueHistoryEntryDto } from '../../dto/issue-history.dto.js';
 import { GetIssueHistoryQuery } from './get-issue-history.query.js';
+import type { IssueChangeField } from '../../../../issue/domain/entities/issue-change.js';
+
+/** Поля, значения которых — id пользователей */
+const USER_FIELDS = new Set<IssueChangeField>(['assignee', 'observer']);
 
 @Injectable()
 export class GetIssueHistoryUseCase {
@@ -55,7 +59,7 @@ export class GetIssueHistoryUseCase {
         oldValue: record.oldValue,
         newValue: record.newValue,
       };
-      if (record.field === 'assignee') {
+      if (USER_FIELDS.has(record.field)) {
         change.oldUser = userOf(record.oldValue);
         change.newUser = userOf(record.newValue);
       }
@@ -65,12 +69,12 @@ export class GetIssueHistoryUseCase {
     return [...entries.values()];
   }
 
-  /** Авторы изменений и назначенные/снятые исполнители */
+  /** Авторы изменений, назначенные/снятые исполнители и наблюдатели */
   private async loadUsers(records: IssueChangeRecord[]): Promise<Map<string, UserDto>> {
     const ids = new Set<string>();
     for (const record of records) {
       if (record.actorId) ids.add(record.actorId);
-      if (record.field === 'assignee') {
+      if (USER_FIELDS.has(record.field)) {
         if (record.oldValue) ids.add(record.oldValue);
         if (record.newValue) ids.add(record.newValue);
       }

src/modules/history/domain/repositories/issue-history.repository.interface.ts

@@ -39,8 +39,8 @@ export interface DailyStatusCount {
 export interface IIssueHistoryRepository {
   /** История задачи от старых изменений к новым */
   findByIssue(issueId: number): Promise<IssueChangeRecord[]>;
-  /** Только задачи, видимые пользователю (reporter/assignee) */
+  /** Только задачи, видимые пользователю (reporter/assignee/наблюдатель) */
   countDailyEvents(range: DailyStatsRange): Promise<DailyEventCount[]>;
-  /** Только задачи, видимые пользователю (reporter/assignee) */
+  /** Только задачи, видимые пользователю (reporter/assignee/наблюдатель) */
   countDailyStatuses(range: DailyStatsRange): Promise<DailyStatusCount[]>;
 }

src/modules/history/infrastructure/persistence/prisma/repositories/issue-history.prisma-repository.ts

@@ -11,13 +11,14 @@ import type {
 } from '../../../../domain/repositories/issue-history.repository.interface.js';
 
 /**
- * Задачи, видимые пользователю: reporter или assignee — то же правило, что
- * ownedByUser в IssuePrismaRepository. Возвращает CTE "visible" (id задач).
+ * Задачи, видимые пользователю: reporter, assignee или наблюдатель — то же
+ * правило, что visibleTo в IssuePrismaRepository. Возвращает CTE "visible" (id задач).
  */
 function visibleIssuesCte(range: DailyStatsRange): Prisma.Sql {
   return Prisma.sql`"visible" AS (
     SELECT "id" FROM "issue"
-    WHERE ("assigneeId" = ${range.userId} OR "reporterId" = ${range.userId})
+    WHERE ("assigneeId" = ${range.userId} OR "reporterId" = ${range.userId}
+      OR EXISTS (SELECT 1 FROM "issue_observer" o WHERE o."issueId" = "issue"."id" AND o."userId" = ${range.userId}))
     ${range.projectId ? Prisma.sql`AND "projectId" = ${range.projectId}` : Prisma.empty}
   )`;
 }

src/modules/issue-attachment/application/services/issue-attachment-file-owner.service.ts

@@ -36,7 +36,7 @@ export class IssueAttachmentFileOwnerService implements FileOwner, OnModuleInit
   /**
    * Файл виден, если видна хоть одна задача, к которой он прикреплён.
    * Видимость проверяем через IIssueRepository.findById, чтобы правило
-   * (reporter/assignee) жило в одном месте. Обычно файл прикреплён к одной задаче.
+   * (reporter/assignee/наблюдатель) жило в одном месте. Обычно файл прикреплён к одной задаче.
    */
   async isVisibleThrough(fileId: string, userId: string): Promise<boolean> {
     const issueIds = await this.attachmentRepository.findIssueIdsByFile(fileId);

src/modules/issue-attachment/application/use-cases/attach-file/attach-file.use-case.ts

@@ -8,6 +8,7 @@ import {
   type IIssueRepository,
 } from '../../../../issue/domain/repositories/issue.repository.interface.js';
 import { IssueNotFoundException } from '../../../../issue/domain/exceptions/issue-not-found.exception.js';
+import { IssueEditForbiddenException } from '../../../../issue/domain/exceptions/issue-edit-forbidden.exception.js';
 import { FileAccessService } from '../../../../file/application/services/file-access.service.js';
 import { IssueAttachment } from '../../../domain/entities/issue-attachment.entity.js';
 import { AttachFileCommand } from './attach-file.command.js';
@@ -15,7 +16,7 @@ import { IssueAttachmentDto } from '../../dto/issue-attachment.dto.js';
 
 /**
  * Прикрепляет к задаче файл, заранее загруженный через POST /files.
- * Прикреплять может любой, кому видна задача (как и править её),
+ * Прикреплять может тот, кто может править задачу (не наблюдатель),
  * но только собственный файл — см. StoredFile.assertOwnedBy.
  */
 @Injectable()
@@ -29,9 +30,13 @@ export class AttachFileUseCase {
   ) {}
 
   async execute(command: AttachFileCommand): Promise<IssueAttachmentDto> {
-    if (!(await this.issueRepository.findById(command.issueId, command.userId))) {
+    const issue = await this.issueRepository.findById(command.issueId, command.userId);
+    if (!issue) {
       throw new IssueNotFoundException(command.issueId);
     }
+    if (!issue.canBeEditedBy(command.userId)) {
+      throw new IssueEditForbiddenException(command.issueId);
+    }
 
     const file = await this.fileAccess.getAttachableFile(command.fileId, command.userId);
     const attachment = await this.attachmentRepository.create(

src/modules/issue-attachment/application/use-cases/detach-file/detach-file.use-case.ts

@@ -8,12 +8,14 @@ import {
   type IIssueRepository,
 } from '../../../../issue/domain/repositories/issue.repository.interface.js';
 import { IssueNotFoundException } from '../../../../issue/domain/exceptions/issue-not-found.exception.js';
+import { IssueEditForbiddenException } from '../../../../issue/domain/exceptions/issue-edit-forbidden.exception.js';
 import { IssueAttachmentNotFoundException } from '../../../domain/exceptions/issue-attachment-not-found.exception.js';
 import { DetachFileCommand } from './detach-file.command.js';
 
 /**
  * Открепляет файл от задачи. Сам файл не удаляется: если он больше
  * ни к чему не прикреплён, его удалит GC file-модуля.
+ * Наблюдателям задачи недоступно — как и её правка.
  */
 @Injectable()
 export class DetachFileUseCase {
@@ -25,9 +27,13 @@ export class DetachFileUseCase {
   ) {}
 
   async execute(command: DetachFileCommand): Promise<void> {
-    if (!(await this.issueRepository.findById(command.issueId, command.userId))) {
+    const issue = await this.issueRepository.findById(command.issueId, command.userId);
+    if (!issue) {
       throw new IssueNotFoundException(command.issueId);
     }
+    if (!issue.canBeEditedBy(command.userId)) {
+      throw new IssueEditForbiddenException(command.issueId);
+    }
 
     if (!(await this.attachmentRepository.delete(command.issueId, command.fileId))) {
       throw new IssueAttachmentNotFoundException(command.issueId, command.fileId);

src/modules/issue-attachment/presentation/controllers/issue-attachment.controller.ts

@@ -23,6 +23,7 @@ import { IssueAttachmentNotFoundException } from '../../domain/exceptions/issue-
 import { IssueNotFoundException } from '../../../issue/domain/exceptions/issue-not-found.exception.js';
 import { FileNotFoundException } from '../../../file/domain/exceptions/file-not-found.exception.js';
 import { FileForbiddenException } from '../../../file/domain/exceptions/file-forbidden.exception.js';
+import { IssueEditForbiddenException } from '../../../issue/domain/exceptions/issue-edit-forbidden.exception.js';
 
 /**
  * Вложения задачи. Сам файл загружается отдельно (POST /files),
@@ -78,7 +79,7 @@ export class IssueAttachmentController {
       ) {
         throw new NotFoundException(error.message);
       }
-      if (error instanceof FileForbiddenException) {
+      if (error instanceof FileForbiddenException || error instanceof IssueEditForbiddenException) {
         throw new ForbiddenException(error.message);
       }
       throw error;

src/modules/issue/application/dto/issue-with-users.dto.ts

@@ -12,6 +12,9 @@ export class IssueWithUsersDto {
   reporterId: string | null;
   assignee: UserDto | null;
   reporter: UserDto | null;
+  observerIds: string[];
+  /** Удалённые пользователи сюда не попадают */
+  observers: UserDto[];
   projectId: string;
   dueDate: Date | null;
   createdAt: Date;

src/modules/issue/application/dto/issue.dto.ts

@@ -8,6 +8,7 @@ export class IssueDto {
   type: string;
   assigneeId: string | null;
   reporterId: string | null;
+  observerIds: string[];
   projectId: string;
   dueDate: Date | null;
   createdAt: Date;

src/modules/issue/application/mappers/issue-application.mapper.ts

@@ -15,6 +15,7 @@ export class IssueApplicationMapper {
       type: issue.type,
       assigneeId: issue.assignee,
       reporterId: issue.reporter,
+      observerIds: [...issue.observers],
       projectId: issue.projectId,
       dueDate: issue.dueDate,
       createdAt: issue.createdAt,
@@ -22,7 +23,7 @@ export class IssueApplicationMapper {
     };
   }
 
-  /** Раскрывает assignee/reporter в полноценных пользователей (см. GetIssueUseCase) */
+  /** Раскрывает assignee/reporter/наблюдателей в полноценных пользователей (см. GetIssueUseCase) */
   static toDtoWithUsers(issue: Issue, usersById: ReadonlyMap<string, UserDto>): IssueWithUsersDto {
     return {
       id: issue.id as number,
@@ -36,6 +37,8 @@ export class IssueApplicationMapper {
       reporterId: issue.reporter,
       assignee: issue.assignee ? (usersById.get(issue.assignee) ?? null) : null,
       reporter: issue.reporter ? (usersById.get(issue.reporter) ?? null) : null,
+      observerIds: [...issue.observers],
+      observers: issue.observers.flatMap((id) => usersById.get(id) ?? []),
       projectId: issue.projectId,
       dueDate: issue.dueDate,
       createdAt: issue.createdAt,

src/modules/issue/application/services/issue-assignment-notifier.service.ts

@@ -1,17 +1,23 @@
 import { Injectable } from '@nestjs/common';
 import { NotificationsService } from '../../../notification/application/services/notifications.service.js';
 import { IssueAssignedEvent } from '../../domain/events/issue-assigned.event.js';
+import { IssueObserverAddedEvent } from '../../domain/events/issue-observer-added.event.js';
 import type { Issue } from '../../domain/entities/issue.entity.js';
 
 /**
  * Уведомляет нового исполнителя задачи (в т.ч. при самоназначении)
- * по всем включённым у него каналам.
+ * и новых наблюдателей по всем включённым у них каналам.
  */
 @Injectable()
 export class IssueAssignmentNotifierService {
   constructor(private readonly notificationsService: NotificationsService) {}
 
   notify(issue: Issue, domainEvents: unknown[]): void {
+    this.notifyAssignee(issue, domainEvents);
+    this.notifyObservers(issue, domainEvents);
+  }
+
+  private notifyAssignee(issue: Issue, domainEvents: unknown[]): void {
     const assigned = domainEvents.findLast((event) => event instanceof IssueAssignedEvent);
     // Последнее назначение могло быть отменено снятием исполнителя в той же операции
     if (!assigned || assigned.assignee !== issue.assignee) return;
@@ -22,4 +28,21 @@ export class IssueAssignmentNotifierService {
       content: issue.title,
     });
   }
+
+  private notifyObservers(issue: Issue, domainEvents: unknown[]): void {
+    const added = new Set(
+      domainEvents.filter((event) => event instanceof IssueObserverAddedEvent).map((event) => event.observer),
+    );
+
+    // Наблюдатель мог быть снят или назначен исполнителем в той же операции
+    for (const userId of added) {
+      if (!issue.observers.includes(userId)) continue;
+
+      this.notificationsService.notify({
+        userId,
+        subject: `You are now observing ${issue.key}`,
+        content: issue.title,
+      });
+    }
+  }
 }

src/modules/issue/application/services/issue-participants.service.ts

@@ -0,0 +1,44 @@
+import { Inject, Injectable } from '@nestjs/common';
+import {
+  PROJECT_REPOSITORY,
+  type IProjectRepository,
+} from '../../../project/domain/repositories/project.repository.interface.js';
+import { GetUsersUseCase } from '../../../user/application/use-cases/get-users/get-users.use-case.js';
+import { GetUsersQuery } from '../../../user/application/use-cases/get-users/get-users.query.js';
+import type { Issue } from '../../domain/entities/issue.entity.js';
+import { IssueObserverNotFoundException } from '../../domain/exceptions/issue-observer-not-found.exception.js';
+
+/** Участники задачи (assignee и наблюдатели) за пределами самой сущности */
+@Injectable()
+export class IssueParticipantsService {
+  constructor(
+    @Inject(PROJECT_REPOSITORY)
+    private readonly projectRepository: IProjectRepository,
+    private readonly getUsersUseCase: GetUsersUseCase,
+  ) {}
+
+  /** Проверяет до сохранения, что новые наблюдатели существуют — иначе упадёт внешний ключ */
+  async ensureObserversExist(userIds: string[]): Promise<void> {
+    if (userIds.length === 0) return;
+
+    const users = await this.getUsersUseCase.execute(new GetUsersQuery(userIds));
+    const found = new Set(users.map((user) => user.id));
+    const missing = userIds.filter((id) => !found.has(id));
+    if (missing.length > 0) {
+      throw new IssueObserverNotFoundException(missing);
+    }
+  }
+
+  /**
+   * Исполнитель и наблюдатели становятся участниками проекта, чтобы видеть его в списке.
+   * Наблюдатель — с ролью OBSERVER: задачи в проекте он создавать не может.
+   */
+  async addToProject(issue: Issue): Promise<void> {
+    if (issue.assignee) {
+      await this.projectRepository.addMember(issue.projectId, issue.assignee, 'MEMBER');
+    }
+    for (const userId of issue.observers) {
+      await this.projectRepository.addMember(issue.projectId, userId, 'OBSERVER');
+    }
+  }
+}

src/modules/issue/application/services/issue-user-expander.service.ts

@@ -5,7 +5,7 @@ import { IssueApplicationMapper } from '../mappers/issue-application.mapper.js';
 import { GetUsersUseCase } from '../../../user/application/use-cases/get-users/get-users.use-case.js';
 import { GetUsersQuery } from '../../../user/application/use-cases/get-users/get-users.query.js';
 
-/** Раскрывает assignee/reporter задачи (или списка задач) в полноценных пользователей */
+/** Раскрывает assignee/reporter/наблюдателей задачи (или списка задач) в полноценных пользователей */
 @Injectable()
 export class IssueUserExpanderService {
   constructor(private readonly getUsersUseCase: GetUsersUseCase) {}
@@ -19,7 +19,11 @@ export class IssueUserExpanderService {
     if (issues.length === 0) return [];
 
     const userIds = [
-      ...new Set(issues.flatMap((issue) => [issue.reporter, issue.assignee]).filter((id): id is string => Boolean(id))),
+      ...new Set(
+        issues
+          .flatMap((issue) => [issue.reporter, issue.assignee, ...issue.observers])
+          .filter((id): id is string => Boolean(id)),
+      ),
     ];
     const users = await this.getUsersUseCase.execute(new GetUsersQuery(userIds));
     const usersById = new Map(users.map((user) => [user.id, user]));

src/modules/issue/application/use-cases/create-issue/create-issue.command.ts

@@ -9,5 +9,6 @@ export class CreateIssueCommand {
     public readonly assignee?: string,
     public readonly dueDate?: Date,
     public readonly type?: string,
+    public readonly observers?: string[],
   ) {}
 }

src/modules/issue/application/use-cases/create-issue/create-issue.use-case.spec.ts

@@ -9,6 +9,11 @@ import { IssueUserExpanderService } from '../../services/issue-user-expander.ser
 import { IssueApplicationMapper } from '../../mappers/issue-application.mapper.js';
 import { IssueAssignmentNotifierService } from '../../services/issue-assignment-notifier.service.js';
 import type { NotificationsService } from '../../../../notification/application/services/notifications.service.js';
+import { IssueParticipantsService } from '../../services/issue-participants.service.js';
+import type { GetUsersUseCase } from '../../../../user/application/use-cases/get-users/get-users.use-case.js';
+import type { GetUsersQuery } from '../../../../user/application/use-cases/get-users/get-users.query.js';
+import { IssueProjectNotFoundException } from '../../../domain/exceptions/issue-project-not-found.exception.js';
+import { IssueProjectForbiddenException } from '../../../domain/exceptions/issue-project-forbidden.exception.js';
 
 describe('CreateIssueUseCase', () => {
   let repository: IIssueRepository;
@@ -16,6 +21,7 @@ describe('CreateIssueUseCase', () => {
   let issueEventsService: IssueEventsService;
   let issueUserExpander: IssueUserExpanderService;
   let notificationsService: NotificationsService;
+  let getUsersUseCase: GetUsersUseCase;
   let useCase: CreateIssueUseCase;
 
   beforeEach(() => {
@@ -35,6 +41,7 @@ describe('CreateIssueUseCase', () => {
       create: vi.fn(),
       update: vi.fn(),
       delete: vi.fn(),
+      findRole: vi.fn(async () => 'MEMBER' as const),
       addMember: vi.fn(),
     };
     issueEventsService = new IssueEventsService();
@@ -46,12 +53,16 @@ describe('CreateIssueUseCase', () => {
       })),
     } as unknown as IssueUserExpanderService;
     notificationsService = { notify: vi.fn() } as unknown as NotificationsService;
+    getUsersUseCase = {
+      execute: vi.fn(async (query: GetUsersQuery) => query.ids.filter((id) => id !== 'ghost').map((id) => ({ id }))),
+    } as unknown as GetUsersUseCase;
     useCase = new CreateIssueUseCase(
       repository,
       projectRepository,
       issueEventsService,
       issueUserExpander,
       new IssueAssignmentNotifierService(notificationsService),
+      new IssueParticipantsService(projectRepository, getUsersUseCase),
     );
   });
 
@@ -186,4 +197,53 @@ describe('CreateIssueUseCase', () => {
     expect(task.type).toBe('TASK');
     expect(bug.type).toBe('BUG');
   });
+
+  it('checks project access on behalf of the reporter', async () => {
+    vi.mocked(repository.create).mockImplementation(async (issue) => issue);
+
+    await useCase.execute(new CreateIssueCommand('ISSUE-1', 'Fix login bug', 'user-1', 'project-1'));
+
+    expect(projectRepository.findRole).toHaveBeenCalledWith('project-1', 'user-1');
+  });
+
+  it('refuses to create an issue in a project the reporter has no access to', async () => {
+    vi.mocked(projectRepository.findRole).mockResolvedValue(null);
+
+    await expect(
+      useCase.execute(new CreateIssueCommand('ISSUE-1', 'Fix login bug', 'user-9', 'project-1')),
+    ).rejects.toBeInstanceOf(IssueProjectNotFoundException);
+    expect(repository.create).not.toHaveBeenCalled();
+    expect(projectRepository.addMember).not.toHaveBeenCalled();
+  });
+
+  it('forbids a project observer from creating issues', async () => {
+    vi.mocked(projectRepository.findRole).mockResolvedValue('OBSERVER');
+
+    await expect(
+      useCase.execute(new CreateIssueCommand('ISSUE-1', 'Fix login bug', 'user-5', 'project-1')),
+    ).rejects.toBeInstanceOf(IssueProjectForbiddenException);
+    expect(repository.create).not.toHaveBeenCalled();
+  });
+
+  it('adds the assignee to the project as a member and observers as observers', async () => {
+    vi.mocked(repository.create).mockImplementation(async (issue) => issue);
+
+    await useCase.execute(
+      new CreateIssueCommand(
+        'ISSUE-1',
+        'Fix login bug',
+        'user-1',
+        'project-1',
+        undefined,
+        undefined,
+        'user-2',
+        undefined,
+        undefined,
+        ['user-3'],
+      ),
+    );
+
+    expect(projectRepository.addMember).toHaveBeenCalledWith('project-1', 'user-2', 'MEMBER');
+    expect(projectRepository.addMember).toHaveBeenCalledWith('project-1', 'user-3', 'OBSERVER');
+  });
 });

src/modules/issue/application/use-cases/create-issue/create-issue.use-case.ts

@@ -5,11 +5,14 @@ import {
   PROJECT_REPOSITORY,
   type IProjectRepository,
 } from '../../../../project/domain/repositories/project.repository.interface.js';
+import { IssueProjectNotFoundException } from '../../../domain/exceptions/issue-project-not-found.exception.js';
+import { IssueProjectForbiddenException } from '../../../domain/exceptions/issue-project-forbidden.exception.js';
 import { CreateIssueCommand } from './create-issue.command.js';
 import { IssueWithUsersDto } from '../../dto/issue-with-users.dto.js';
 import { IssueEventsService } from '../../services/issue-events.service.js';
 import { IssueUserExpanderService } from '../../services/issue-user-expander.service.js';
 import { IssueAssignmentNotifierService } from '../../services/issue-assignment-notifier.service.js';
+import { IssueParticipantsService } from '../../services/issue-participants.service.js';
 import { IssueCreatedEvent } from '../../../domain/events/issue-created.event.js';
 
 @Injectable()
@@ -22,6 +25,7 @@ export class CreateIssueUseCase {
     private readonly issueEventsService: IssueEventsService,
     private readonly issueUserExpander: IssueUserExpanderService,
     private readonly issueAssignmentNotifier: IssueAssignmentNotifierService,
+    private readonly issueParticipants: IssueParticipantsService,
   ) {}
 
   async execute(command: CreateIssueCommand): Promise<IssueWithUsersDto> {
@@ -33,16 +37,26 @@ export class CreateIssueUseCase {
       type: command.type,
       assignee: command.assignee,
       reporter: command.reporter,
+      observers: command.observers,
       projectId: command.projectId,
       dueDate: command.dueDate,
     });
 
+    // Создавать задачи может владелец или участник проекта, но не наблюдатель.
+    // Чужой проект неотличим от несуществующего — 404, как и раньше.
+    const role = await this.projectRepository.findRole(command.projectId, command.reporter);
+    if (!role) {
+      throw new IssueProjectNotFoundException(command.projectId);
+    }
+    if (role === 'OBSERVER') {
+      throw new IssueProjectForbiddenException(command.projectId);
+    }
+
+    await this.issueParticipants.ensureObserversExist([...draft.observers]);
     const issue = await this.issueRepository.create(draft);
     const dto = await this.issueUserExpander.expand(issue);
 
-    if (issue.assignee) {
-      await this.projectRepository.addMember(issue.projectId, issue.assignee);
-    }
+    await this.issueParticipants.addToProject(issue);
 
     const domainEvents = draft.pullDomainEvents();
     this.issueAssignmentNotifier.notify(issue, domainEvents);

src/modules/issue/application/use-cases/delete-issue/delete-issue.use-case.spec.ts

@@ -2,6 +2,7 @@ import { beforeEach, describe, expect, it, vi } from 'vitest';
 import type { IIssueRepository } from '../../../domain/repositories/issue.repository.interface.js';
 import { Issue } from '../../../domain/entities/issue.entity.js';
 import { IssueNotFoundException } from '../../../domain/exceptions/issue-not-found.exception.js';
+import { IssueEditForbiddenException } from '../../../domain/exceptions/issue-edit-forbidden.exception.js';
 import { DeleteIssueUseCase } from './delete-issue.use-case.js';
 import { DeleteIssueCommand } from './delete-issue.command.js';
 import { IssueEventsService } from '../../services/issue-events.service.js';
@@ -17,6 +18,7 @@ const buildIssue = () =>
     type: 'TASK',
     assignee: null,
     reporter: 'user-1',
+    observers: ['user-5'],
     projectId: 'project-1',
     dueDate: null,
     createdAt: new Date(),
@@ -73,4 +75,13 @@ describe('DeleteIssueUseCase', () => {
       }),
     ]);
   });
+
+  it('forbids an observer from deleting the issue', async () => {
+    vi.mocked(repository.findById).mockResolvedValue(buildIssue());
+
+    await expect(useCase.execute(new DeleteIssueCommand(1, 'user-5'))).rejects.toBeInstanceOf(
+      IssueEditForbiddenException,
+    );
+    expect(repository.delete).not.toHaveBeenCalled();
+  });
 });

src/modules/issue/application/use-cases/delete-issue/delete-issue.use-case.ts

@@ -1,6 +1,7 @@
 import { Inject, Injectable } from '@nestjs/common';
 import { ISSUE_REPOSITORY, type IIssueRepository } from '../../../domain/repositories/issue.repository.interface.js';
 import { IssueNotFoundException } from '../../../domain/exceptions/issue-not-found.exception.js';
+import { IssueEditForbiddenException } from '../../../domain/exceptions/issue-edit-forbidden.exception.js';
 import { DeleteIssueCommand } from './delete-issue.command.js';
 import { IssueApplicationMapper } from '../../mappers/issue-application.mapper.js';
 import { IssueEventsService } from '../../services/issue-events.service.js';
@@ -20,6 +21,10 @@ export class DeleteIssueUseCase {
       throw new IssueNotFoundException(command.id);
     }
 
+    if (!issue.canBeEditedBy(command.userId)) {
+      throw new IssueEditForbiddenException(command.id);
+    }
+
     await this.issueRepository.delete(command.id);
 
     this.issueEventsService.emitIssueDeleted(IssueApplicationMapper.toDto(issue));

src/modules/issue/application/use-cases/list-issues/list-issues.query.ts

@@ -1,3 +1,5 @@
+import type { IssueUserRole } from '../../../domain/repositories/issue.repository.interface.js';
+
 export class ListIssuesQuery {
   constructor(
     public readonly limit: number,
@@ -9,5 +11,6 @@ export class ListIssuesQuery {
     public readonly assigneeId?: string,
     public readonly hasDueDate?: boolean,
     public readonly type?: string[],
+    public readonly role?: IssueUserRole,
   ) {}
 }

src/modules/issue/application/use-cases/list-issues/list-issues.use-case.ts

@@ -24,6 +24,7 @@ export class ListIssuesUseCase {
       assigneeId: query.assigneeId,
       hasDueDate: query.hasDueDate,
       type: query.type,
+      role: query.role,
     });
 
     return { list: await this.issueUserExpander.expandAll(list), meta };

src/modules/issue/application/use-cases/unobserve-issue/unobserve-issue.command.ts

@@ -0,0 +1,6 @@
+export class UnobserveIssueCommand {
+  constructor(
+    public readonly id: number,
+    public readonly userId: string,
+  ) {}
+}

src/modules/issue/application/use-cases/unobserve-issue/unobserve-issue.use-case.spec.ts

@@ -0,0 +1,75 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+import type { IIssueRepository } from '../../../domain/repositories/issue.repository.interface.js';
+import { Issue } from '../../../domain/entities/issue.entity.js';
+import { IssueNotFoundException } from '../../../domain/exceptions/issue-not-found.exception.js';
+import { IssueEventsService } from '../../services/issue-events.service.js';
+import { UnobserveIssueUseCase } from './unobserve-issue.use-case.js';
+import { UnobserveIssueCommand } from './unobserve-issue.command.js';
+
+const buildIssue = () =>
+  Issue.reconstitute({
+    id: 1,
+    key: 'ISSUE-1',
+    title: 'Title',
+    content: null,
+    status: 'OPEN',
+    priority: 0,
+    type: 'TASK',
+    assignee: null,
+    reporter: 'user-1',
+    observers: ['user-5', 'user-6'],
+    projectId: 'project-1',
+    dueDate: null,
+    createdAt: new Date(),
+    updatedAt: new Date(),
+  });
+
+describe('UnobserveIssueUseCase', () => {
+  let repository: IIssueRepository;
+  let issueEventsService: IssueEventsService;
+  let useCase: UnobserveIssueUseCase;
+
+  beforeEach(() => {
+    repository = {
+      findById: vi.fn(),
+      findByCKey: vi.fn(),
+      findAll: vi.fn(),
+      findByDueDateRange: vi.fn(),
+      countByStatus: vi.fn(),
+      create: vi.fn(),
+      update: vi.fn(),
+      delete: vi.fn(),
+    };
+    issueEventsService = new IssueEventsService();
+    useCase = new UnobserveIssueUseCase(repository, issueEventsService);
+  });
+
+  it('removes the current user from observers on behalf of themselves', async () => {
+    vi.mocked(repository.findById).mockResolvedValue(buildIssue());
+    const received: unknown[] = [];
+    issueEventsService.onIssueUpdated().subscribe((issue) => received.push(issue));
+
+    await useCase.execute(new UnobserveIssueCommand(1, 'user-5'));
+
+    const [saved, actorId] = vi.mocked(repository.update).mock.calls[0]!;
+    expect(saved.observers).toEqual(['user-6']);
+    expect(actorId).toBe('user-5');
+    expect(received).toEqual([expect.objectContaining({ observerIds: ['user-6'] })]);
+  });
+
+  it('does nothing for a user who is not an observer', async () => {
+    vi.mocked(repository.findById).mockResolvedValue(buildIssue());
+
+    await useCase.execute(new UnobserveIssueCommand(1, 'user-1'));
+
+    expect(repository.update).not.toHaveBeenCalled();
+  });
+
+  it('throws when the issue is not visible', async () => {
+    vi.mocked(repository.findById).mockResolvedValue(null);
+
+    await expect(useCase.execute(new UnobserveIssueCommand(1, 'user-9'))).rejects.toBeInstanceOf(
+      IssueNotFoundException,
+    );
+  });
+});

src/modules/issue/application/use-cases/unobserve-issue/unobserve-issue.use-case.ts

@@ -0,0 +1,35 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { ISSUE_REPOSITORY, type IIssueRepository } from '../../../domain/repositories/issue.repository.interface.js';
+import { IssueNotFoundException } from '../../../domain/exceptions/issue-not-found.exception.js';
+import { IssueEventsService } from '../../services/issue-events.service.js';
+import { IssueApplicationMapper } from '../../mappers/issue-application.mapper.js';
+import { UnobserveIssueCommand } from './unobserve-issue.command.js';
+
+/**
+ * Наблюдатель сам отписывается от задачи. Редактировать задачу он не может,
+ * поэтому это отдельная операция, а не часть UpdateIssueUseCase.
+ * Повторный вызов (или вызов не наблюдателем) ничего не меняет.
+ */
+@Injectable()
+export class UnobserveIssueUseCase {
+  constructor(
+    @Inject(ISSUE_REPOSITORY)
+    private readonly issueRepository: IIssueRepository,
+    private readonly issueEventsService: IssueEventsService,
+  ) {}
+
+  async execute(command: UnobserveIssueCommand): Promise<void> {
+    const issue = await this.issueRepository.findById(command.id, command.userId);
+
+    if (!issue) {
+      throw new IssueNotFoundException(command.id);
+    }
+
+    if (!issue.observers.includes(command.userId)) return;
+
+    issue.removeObserver(command.userId);
+    await this.issueRepository.update(issue, command.userId);
+
+    this.issueEventsService.emitIssueUpdated(IssueApplicationMapper.toDto(issue));
+  }
+}

src/modules/issue/application/use-cases/update-issue/update-issue.command.ts

@@ -9,5 +9,7 @@ export class UpdateIssueCommand {
     public readonly assignee?: string | null,
     public readonly dueDate?: Date | null,
     public readonly type?: string,
+    /** Полный новый список наблюдателей */
+    public readonly observers?: string[],
   ) {}
 }

src/modules/issue/application/use-cases/update-issue/update-issue.use-case.spec.ts

@@ -3,6 +3,8 @@ import type { IIssueRepository } from '../../../domain/repositories/issue.reposi
 import type { IProjectRepository } from '../../../../project/domain/repositories/project.repository.interface.js';
 import { Issue } from '../../../domain/entities/issue.entity.js';
 import { IssueNotFoundException } from '../../../domain/exceptions/issue-not-found.exception.js';
+import { IssueEditForbiddenException } from '../../../domain/exceptions/issue-edit-forbidden.exception.js';
+import { IssueObserverNotFoundException } from '../../../domain/exceptions/issue-observer-not-found.exception.js';
 import { UpdateIssueUseCase } from './update-issue.use-case.js';
 import { UpdateIssueCommand } from './update-issue.command.js';
 import { IssueEventsService } from '../../services/issue-events.service.js';
@@ -10,8 +12,11 @@ import { IssueUserExpanderService } from '../../services/issue-user-expander.ser
 import { IssueApplicationMapper } from '../../mappers/issue-application.mapper.js';
 import { IssueAssignmentNotifierService } from '../../services/issue-assignment-notifier.service.js';
 import type { NotificationsService } from '../../../../notification/application/services/notifications.service.js';
+import { IssueParticipantsService } from '../../services/issue-participants.service.js';
+import type { GetUsersUseCase } from '../../../../user/application/use-cases/get-users/get-users.use-case.js';
+import type { GetUsersQuery } from '../../../../user/application/use-cases/get-users/get-users.query.js';
 
-const buildIssue = () =>
+const buildIssue = (overrides: { assignee?: string | null; observers?: string[] } = {}) =>
   Issue.reconstitute({
     id: 1,
     key: 'ISSUE-1',
@@ -26,6 +31,7 @@ const buildIssue = () =>
     dueDate: null,
     createdAt: new Date('2026-01-01T00:00:00.000Z'),
     updatedAt: new Date('2026-01-01T00:00:00.000Z'),
+    ...overrides,
   });
 
 describe('UpdateIssueUseCase', () => {
@@ -34,6 +40,7 @@ describe('UpdateIssueUseCase', () => {
   let issueEventsService: IssueEventsService;
   let issueUserExpander: IssueUserExpanderService;
   let notificationsService: NotificationsService;
+  let getUsersUseCase: GetUsersUseCase;
   let useCase: UpdateIssueUseCase;
 
   beforeEach(() => {
@@ -53,6 +60,7 @@ describe('UpdateIssueUseCase', () => {
       create: vi.fn(),
       update: vi.fn(),
       delete: vi.fn(),
+      findRole: vi.fn(),
       addMember: vi.fn(),
     };
     issueEventsService = new IssueEventsService();
@@ -64,12 +72,15 @@ describe('UpdateIssueUseCase', () => {
       })),
     } as unknown as IssueUserExpanderService;
     notificationsService = { notify: vi.fn() } as unknown as NotificationsService;
+    getUsersUseCase = {
+      execute: vi.fn(async (query: GetUsersQuery) => query.ids.filter((id) => id !== 'ghost').map((id) => ({ id }))),
+    } as unknown as GetUsersUseCase;
     useCase = new UpdateIssueUseCase(
       repository,
-      projectRepository,
       issueEventsService,
       issueUserExpander,
       new IssueAssignmentNotifierService(notificationsService),
+      new IssueParticipantsService(projectRepository, getUsersUseCase),
     );
   });
 
@@ -85,7 +96,7 @@ describe('UpdateIssueUseCase', () => {
   });
 
   it('passes the acting user to the repository as the author of the changes', async () => {
-    vi.mocked(repository.findById).mockResolvedValue(buildIssue());
+    vi.mocked(repository.findById).mockResolvedValue(buildIssue({ assignee: 'user-7' }));
 
     await useCase.execute(new UpdateIssueCommand(1, 'user-7', undefined, undefined, 'DONE'));
 
@@ -166,4 +177,77 @@ describe('UpdateIssueUseCase', () => {
 
     expect(dto.type).toBe('BUG');
   });
+
+  describe('observers', () => {
+    it('forbids an observer from editing the issue', async () => {
+      vi.mocked(repository.findById).mockResolvedValue(buildIssue({ observers: ['user-5'] }));
+
+      await expect(useCase.execute(new UpdateIssueCommand(1, 'user-5', 'Hijacked'))).rejects.toBeInstanceOf(
+        IssueEditForbiddenException,
+      );
+      expect(repository.update).not.toHaveBeenCalled();
+    });
+
+    it('replaces observers, adds them to the project and notifies only the new ones', async () => {
+      vi.mocked(repository.findById).mockResolvedValue(buildIssue({ observers: ['user-5', 'user-6'] }));
+
+      const dto = await useCase.execute(
+        new UpdateIssueCommand(
+          1,
+          'user-1',
+          undefined,
+          undefined,
+          undefined,
+          undefined,
+          undefined,
+          undefined,
+          undefined,
+          ['user-6', 'user-8'],
+        ),
+      );
+
+      expect(dto.observerIds).toEqual(['user-6', 'user-8']);
+      expect(getUsersUseCase.execute).toHaveBeenCalledWith(expect.objectContaining({ ids: ['user-8'] }));
+      expect(projectRepository.addMember).toHaveBeenCalledWith('project-1', 'user-8', 'OBSERVER');
+      expect(notificationsService.notify).toHaveBeenCalledTimes(1);
+      expect(notificationsService.notify).toHaveBeenCalledWith({
+        userId: 'user-8',
+        subject: 'You are now observing ISSUE-1',
+        content: 'Original title',
+      });
+    });
+
+    it('rejects unknown users before saving', async () => {
+      vi.mocked(repository.findById).mockResolvedValue(buildIssue());
+
+      await expect(
+        useCase.execute(
+          new UpdateIssueCommand(
+            1,
+            'user-1',
+            undefined,
+            undefined,
+            undefined,
+            undefined,
+            undefined,
+            undefined,
+            undefined,
+            ['ghost'],
+          ),
+        ),
+      ).rejects.toBeInstanceOf(IssueObserverNotFoundException);
+      expect(repository.update).not.toHaveBeenCalled();
+    });
+
+    it('drops the new assignee from observers', async () => {
+      vi.mocked(repository.findById).mockResolvedValue(buildIssue({ observers: ['user-5'] }));
+
+      const dto = await useCase.execute(
+        new UpdateIssueCommand(1, 'user-1', undefined, undefined, undefined, undefined, 'user-5'),
+      );
+
+      expect(dto.assigneeId).toBe('user-5');
+      expect(dto.observerIds).toEqual([]);
+    });
+  });
 });

src/modules/issue/application/use-cases/update-issue/update-issue.use-case.ts

@@ -1,15 +1,13 @@
 import { Inject, Injectable } from '@nestjs/common';
 import { ISSUE_REPOSITORY, type IIssueRepository } from '../../../domain/repositories/issue.repository.interface.js';
-import {
-  PROJECT_REPOSITORY,
-  type IProjectRepository,
-} from '../../../../project/domain/repositories/project.repository.interface.js';
 import { IssueNotFoundException } from '../../../domain/exceptions/issue-not-found.exception.js';
+import { IssueEditForbiddenException } from '../../../domain/exceptions/issue-edit-forbidden.exception.js';
 import { UpdateIssueCommand } from './update-issue.command.js';
 import { IssueWithUsersDto } from '../../dto/issue-with-users.dto.js';
 import { IssueEventsService } from '../../services/issue-events.service.js';
 import { IssueUserExpanderService } from '../../services/issue-user-expander.service.js';
 import { IssueAssignmentNotifierService } from '../../services/issue-assignment-notifier.service.js';
+import { IssueParticipantsService } from '../../services/issue-participants.service.js';
 import { IssueUpdatedEvent } from '../../../domain/events/issue-updated.event.js';
 
 @Injectable()
@@ -17,11 +15,10 @@ export class UpdateIssueUseCase {
   constructor(
     @Inject(ISSUE_REPOSITORY)
     private readonly issueRepository: IIssueRepository,
-    @Inject(PROJECT_REPOSITORY)
-    private readonly projectRepository: IProjectRepository,
     private readonly issueEventsService: IssueEventsService,
     private readonly issueUserExpander: IssueUserExpanderService,
     private readonly issueAssignmentNotifier: IssueAssignmentNotifierService,
+    private readonly issueParticipants: IssueParticipantsService,
   ) {}
 
   async execute(command: UpdateIssueCommand): Promise<IssueWithUsersDto> {
@@ -31,6 +28,12 @@ export class UpdateIssueUseCase {
       throw new IssueNotFoundException(command.id);
     }
 
+    if (!issue.canBeEditedBy(command.userId)) {
+      throw new IssueEditForbiddenException(command.id);
+    }
+
+    const observersBefore = [...issue.observers];
+
     if (command.title !== undefined) {
       issue.updateTitle(command.title);
     }
@@ -63,12 +66,16 @@ export class UpdateIssueUseCase {
       issue.updateDueDate(command.dueDate);
     }
 
+    // После assignee: новый исполнитель отбрасывается из наблюдателей
+    if (command.observers !== undefined) {
+      issue.setObservers(command.observers);
+    }
+
+    await this.issueParticipants.ensureObserversExist(issue.observers.filter((id) => !observersBefore.includes(id)));
     await this.issueRepository.update(issue, command.userId);
     const dto = await this.issueUserExpander.expand(issue);
 
-    if (issue.assignee) {
-      await this.projectRepository.addMember(issue.projectId, issue.assignee);
-    }
+    await this.issueParticipants.addToProject(issue);
 
     const domainEvents = issue.pullDomainEvents();
     this.issueAssignmentNotifier.notify(issue, domainEvents);

src/modules/issue/domain/entities/issue-change.ts

@@ -11,6 +11,7 @@ export const ISSUE_CHANGE_FIELDS = [
   'type',
   'assignee',
   'dueDate',
+  'observer',
 ] as const;
 
 export type IssueChangeField = (typeof ISSUE_CHANGE_FIELDS)[number];
@@ -18,6 +19,8 @@ export type IssueChangeField = (typeof ISSUE_CHANGE_FIELDS)[number];
 /**
  * Изменение одного поля задачи. Значения сериализованы в строки:
  * priority — число, dueDate — ISO-дата, assignee — id пользователя.
+ * observer — одна строка на наблюдателя: добавлен (oldValue = null, newValue = id)
+ * или снят (oldValue = id, newValue = null).
  */
 export interface IssueFieldChange {
   field: IssueChangeField;

src/modules/issue/domain/entities/issue.entity.spec.ts

@@ -2,6 +2,7 @@ import { describe, expect, it } from 'vitest';
 import { Issue } from './issue.entity.js';
 import { IssueCreatedEvent } from '../events/issue-created.event.js';
 import { IssueAssignedEvent } from '../events/issue-assigned.event.js';
+import { IssueObserverAddedEvent } from '../events/issue-observer-added.event.js';
 
 describe('Issue', () => {
   describe('create', () => {
@@ -248,4 +249,92 @@ describe('Issue', () => {
       expect(issue.pullChanges()).toEqual([{ field: 'status', oldValue: 'OPEN', newValue: 'DONE' }]);
     });
   });
+
+  describe('observers', () => {
+    const load = (observers: string[] = []) =>
+      Issue.reconstitute({
+        id: 1,
+        key: 'ISSUE-1',
+        title: 'Title',
+        content: null,
+        status: 'OPEN',
+        priority: 0,
+        type: 'TASK',
+        assignee: 'user-2',
+        reporter: 'user-1',
+        observers,
+        projectId: 'project-1',
+        dueDate: null,
+        createdAt: new Date(),
+        updatedAt: new Date(),
+      });
+
+    it('only the reporter and the assignee can edit the issue', () => {
+      const issue = load(['user-3']);
+
+      expect(issue.canBeEditedBy('user-1')).toBe(true);
+      expect(issue.canBeEditedBy('user-2')).toBe(true);
+      expect(issue.canBeEditedBy('user-3')).toBe(false);
+    });
+
+    it('creates an issue with observers, skipping duplicates, the reporter and the assignee', () => {
+      const issue = Issue.create({
+        key: 'ISSUE-1',
+        title: 'Title',
+        reporter: 'user-1',
+        assignee: 'user-2',
+        observers: ['user-3', 'user-1', 'user-2', 'user-3', 'user-4'],
+        projectId: 'project-1',
+      });
+
+      expect(issue.observers).toEqual(['user-3', 'user-4']);
+      expect(issue.pullDomainEvents().filter((event) => event instanceof IssueObserverAddedEvent)).toEqual([
+        expect.objectContaining({ observer: 'user-3' }),
+        expect.objectContaining({ observer: 'user-4' }),
+      ]);
+      expect(issue.pullChanges().map((change) => change.field)).toEqual(['created', 'status']);
+    });
+
+    it('records one history row per added or removed observer', () => {
+      const issue = load(['user-3', 'user-4']);
+
+      issue.setObservers(['user-4', 'user-5']);
+
+      expect(issue.observers).toEqual(['user-4', 'user-5']);
+      expect(issue.pullChanges()).toEqual([
+        { field: 'observer', oldValue: 'user-3', newValue: null },
+        { field: 'observer', oldValue: null, newValue: 'user-5' },
+      ]);
+    });
+
+    it('does nothing when the list is unchanged', () => {
+      const issue = load(['user-3']);
+
+      issue.setObservers(['user-3', 'user-1']);
+
+      expect(issue.pullChanges()).toEqual([]);
+      expect(issue.pullDomainEvents()).toEqual([]);
+    });
+
+    it('cancels out adding and removing the same observer', () => {
+      const issue = load();
+
+      issue.addObserver('user-3');
+      issue.removeObserver('user-3');
+
+      expect(issue.pullChanges()).toEqual([]);
+    });
+
+    it('removes the observer who becomes the assignee', () => {
+      const issue = load(['user-3']);
+
+      issue.assignTo('user-3');
+
+      expect(issue.observers).toEqual([]);
+      expect(issue.pullChanges()).toEqual([
+        { field: 'assignee', oldValue: 'user-2', newValue: 'user-3' },
+        { field: 'observer', oldValue: 'user-3', newValue: null },
+      ]);
+    });
+  });
 });

src/modules/issue/domain/entities/issue.entity.ts

@@ -5,6 +5,7 @@ import { IssueType } from '../value-objects/issue-type.vo.js';
 import { IssueCreatedEvent } from '../events/issue-created.event.js';
 import { IssueUpdatedEvent } from '../events/issue-updated.event.js';
 import { IssueAssignedEvent } from '../events/issue-assigned.event.js';
+import { IssueObserverAddedEvent } from '../events/issue-observer-added.event.js';
 import type { IssueChangeField, IssueFieldChange } from './issue-change.js';
 
 interface IssueProps {
@@ -18,6 +19,8 @@ interface IssueProps {
   assignee: string | null;
   /** null — автор задачи удалил аккаунт */
   reporter: string | null;
+  /** Видят задачу и комментируют, но не редактируют. Не пересекаются с reporter/assignee. */
+  observers: string[];
   projectId: string;
   dueDate: Date | null;
   createdAt: Date;
@@ -37,8 +40,11 @@ interface IssueProps {
  */
 export class Issue {
   private domainEvents: unknown[] = [];
-  /** Несохранённые изменения полей, по одному на поле, в порядке изменения */
-  private changes = new Map<IssueChangeField, IssueFieldChange>();
+  /**
+   * Несохранённые изменения полей, по одному на поле, в порядке изменения.
+   * Ключ — поле, для observer — поле и id наблюдателя.
+   */
+  private changes = new Map<string, IssueFieldChange>();
 
   private constructor(private readonly props: IssueProps) {}
 
@@ -51,6 +57,7 @@ export class Issue {
     type?: string;
     assignee?: string | null;
     reporter: string;
+    observers?: string[];
     projectId: string;
     dueDate?: Date | null;
   }): Issue {
@@ -64,6 +71,7 @@ export class Issue {
       type: params.type !== undefined ? IssueType.create(params.type) : IssueType.default(),
       assignee: params.assignee ?? null,
       reporter: params.reporter,
+      observers: [],
       projectId: params.projectId,
       dueDate: params.dueDate ?? null,
       createdAt: new Date(),
@@ -76,6 +84,11 @@ export class Issue {
     if (issue.assignee) {
       issue.addDomainEvent(new IssueAssignedEvent(issue.key, issue.assignee));
     }
+    // Как и assignee, наблюдатели при создании в историю не пишутся — только события
+    for (const userId of issue.normalizeObservers(params.observers ?? [])) {
+      issue.props.observers.push(userId);
+      issue.addDomainEvent(new IssueObserverAddedEvent(issue.key, userId));
+    }
 
     return issue;
   }
@@ -91,6 +104,7 @@ export class Issue {
     type: string;
     assignee: string | null;
     reporter: string | null;
+    observers?: string[];
     projectId: string;
     dueDate: Date | null;
     createdAt: Date;
@@ -106,6 +120,7 @@ export class Issue {
       type: IssueType.create(props.type),
       assignee: props.assignee,
       reporter: props.reporter,
+      observers: [...(props.observers ?? [])],
       projectId: props.projectId,
       dueDate: props.dueDate,
       createdAt: props.createdAt,
@@ -149,6 +164,15 @@ export class Issue {
     return this.props.reporter;
   }
 
+  get observers(): readonly string[] {
+    return this.props.observers;
+  }
+
+  /** Редактировать задачу могут только reporter и assignee, наблюдатели — нет */
+  canBeEditedBy(userId: string): boolean {
+    return this.reporter === userId || this.assignee === userId;
+  }
+
   get projectId(): string {
     return this.props.projectId;
   }
@@ -200,6 +224,8 @@ export class Issue {
     this.recordChange('assignee', this.assignee, userId);
     this.props.assignee = userId;
     this.addDomainEvent(new IssueAssignedEvent(this.key, userId));
+    // Исполнитель и так видит задачу и может её редактировать
+    this.removeObserver(userId);
   }
 
   unassign(): void {
@@ -212,6 +238,35 @@ export class Issue {
     this.props.dueDate = dueDate;
   }
 
+  /**
+   * Заменяет список наблюдателей. reporter и assignee отбрасываются:
+   * у них и так больше прав, чем у наблюдателя.
+   */
+  setObservers(userIds: string[]): void {
+    const next = this.normalizeObservers(userIds);
+    for (const userId of this.observers.filter((id) => !next.includes(id))) {
+      this.removeObserver(userId);
+    }
+    for (const userId of next) {
+      this.addObserver(userId);
+    }
+  }
+
+  addObserver(userId: string): void {
+    if (this.observers.includes(userId) || this.normalizeObservers([userId]).length === 0) return;
+
+    this.recordChange('observer', null, userId, `observer:${userId}`);
+    this.props.observers.push(userId);
+    this.addDomainEvent(new IssueObserverAddedEvent(this.key, userId));
+  }
+
+  removeObserver(userId: string): void {
+    if (!this.observers.includes(userId)) return;
+
+    this.recordChange('observer', userId, null, `observer:${userId}`);
+    this.props.observers = this.props.observers.filter((id) => id !== userId);
+  }
+
   /** Изменения полей, накопленные с момента загрузки/создания. Забираются один раз. */
   pullChanges(): IssueFieldChange[] {
     const changes = [...this.changes.values()];
@@ -224,14 +279,19 @@ export class Issue {
    * ни updatedAt, ни событие, ни запись в историю. Повторная правка поля
    * сливается с предыдущей, а возврат к исходному значению её отменяет.
    */
-  private recordChange(field: IssueChangeField, oldValue: string | null, newValue: string | null): void {
+  private recordChange(
+    field: IssueChangeField,
+    oldValue: string | null,
+    newValue: string | null,
+    key: string = field,
+  ): void {
     if (oldValue === newValue) return;
 
-    const pending = this.changes.get(field);
+    const pending = this.changes.get(key);
     if (!pending) {
-      this.changes.set(field, { field, oldValue, newValue });
+      this.changes.set(key, { field, oldValue, newValue });
     } else if (pending.oldValue === newValue) {
-      this.changes.delete(field);
+      this.changes.delete(key);
     } else {
       pending.newValue = newValue;
     }
@@ -239,6 +299,11 @@ export class Issue {
     this.touch();
   }
 
+  /** Уникальные id без reporter/assignee, в исходном порядке */
+  private normalizeObservers(userIds: string[]): string[] {
+    return [...new Set(userIds)].filter((id) => id !== '' && id !== this.reporter && id !== this.assignee);
+  }
+
   private touch(): void {
     this.props.updatedAt = new Date();
     this.addDomainEvent(new IssueUpdatedEvent(this.key));

src/modules/issue/domain/events/issue-observer-added.event.ts

@@ -0,0 +1,7 @@
+export class IssueObserverAddedEvent {
+  constructor(
+    public readonly issueKey: string,
+    public readonly observer: string,
+    public readonly occurredAt: Date = new Date(),
+  ) {}
+}

src/modules/issue/domain/exceptions/issue-edit-forbidden.exception.ts

@@ -0,0 +1,7 @@
+/** Задача видна пользователю (он наблюдатель), но редактировать её он не может */
+export class IssueEditForbiddenException extends Error {
+  constructor(id: number) {
+    super(`Задача с id=${id} доступна наблюдателю только для чтения`);
+    this.name = 'IssueEditForbiddenException';
+  }
+}

src/modules/issue/domain/exceptions/issue-observer-not-found.exception.ts

@@ -0,0 +1,6 @@
+export class IssueObserverNotFoundException extends Error {
+  constructor(userIds: string[]) {
+    super(`Пользователи не найдены: ${userIds.join(', ')}`);
+    this.name = 'IssueObserverNotFoundException';
+  }
+}

src/modules/issue/domain/exceptions/issue-project-forbidden.exception.ts

@@ -0,0 +1,7 @@
+/** Проект виден пользователю (он наблюдатель), но создавать в нём задачи он не может */
+export class IssueProjectForbiddenException extends Error {
+  constructor(projectId: string) {
+    super(`В проекте с id=${projectId} наблюдатель не может создавать задачи`);
+    this.name = 'IssueProjectForbiddenException';
+  }
+}

src/modules/issue/domain/repositories/issue.repository.interface.ts

@@ -4,8 +4,15 @@ import { PaginationMeta } from '../../../../common/interfaces/pagination-meta.in
 /** DI-токен, т.к. интерфейсы стираются при компиляции TS */
 export const ISSUE_REPOSITORY = Symbol('ISSUE_REPOSITORY');
 
+/** Роль пользователя в задаче — фильтр списка «мои задачи» */
+export const ISSUE_USER_ROLES = ['assigned', 'reported', 'observing'] as const;
+export type IssueUserRole = (typeof ISSUE_USER_ROLES)[number];
+
 export interface IIssueRepository {
-  /** Задача видна только пользователю, который является в ней reporter или assignee */
+  /**
+   * Задача видна своим reporter, assignee и наблюдателям. Редактировать её
+   * могут только reporter и assignee — см. Issue.canBeEditedBy.
+   */
   findById(id: number, userId: string): Promise<Issue | null>;
   findByCKey(ckey: string, userId: string): Promise<Issue | null>;
   findAll(params: {
@@ -18,6 +25,7 @@ export interface IIssueRepository {
     projectId?: string;
     hasDueDate?: boolean;
     type?: string[];
+    role?: IssueUserRole;
   }): Promise<{ list: Issue[]; meta: PaginationMeta }>;
   /** Задачи с dueDate в [from, to), по возрастанию dueDate, не больше limit */
   findByDueDateRange(params: {
@@ -32,7 +40,7 @@ export interface IIssueRepository {
   countByStatus(userId: string, projectId?: string): Promise<Array<{ status: string; count: number }>>;
   /** Сохраняет задачу и записи о её создании в историю (автор — reporter) */
   create(issue: Issue): Promise<Issue>;
-  /** Сохраняет задачу и накопленные изменения полей в историю одной транзакцией */
+  /** Сохраняет задачу, её наблюдателей и накопленные изменения полей в историю одной транзакцией */
   update(issue: Issue, actorId: string): Promise<void>;
   delete(id: number): Promise<void>;
 }

src/modules/issue/infrastructure/persistence/prisma/mappers/issue.mapper.spec.ts

@@ -17,6 +17,7 @@ describe('IssuePrismaMapper', () => {
     dueDate: null,
     createdAt: new Date('2026-01-01T00:00:00.000Z'),
     updatedAt: new Date('2026-01-02T00:00:00.000Z'),
+    observers: [{ userId: 'user-3' }],
   };
 
   it('maps a Prisma record to a domain entity', () => {
@@ -29,6 +30,7 @@ describe('IssuePrismaMapper', () => {
     expect(issue.priority).toBe(2);
     expect(issue.type).toBe('BUG');
     expect(issue.assignee).toBe('user-2');
+    expect(issue.observers).toEqual(['user-3']);
   });
 
   it('maps a new domain entity to Prisma create input', () => {

src/modules/issue/infrastructure/persistence/prisma/mappers/issue.mapper.ts

@@ -2,8 +2,11 @@ import type { Issue as PrismaIssue, Prisma } from '../../../../../../generated/p
 import { Issue } from '../../../../domain/entities/issue.entity.js';
 import { getCKey } from '../../../../domain/helpers/get-ckey.js';
 
+/** Запись задачи вместе с id наблюдателей (см. WITH_OBSERVERS в репозитории) */
+export type PrismaIssueWithObservers = PrismaIssue & { observers: Array<{ userId: string }> };
+
 export class IssuePrismaMapper {
-  static toDomain(record: PrismaIssue): Issue {
+  static toDomain(record: PrismaIssueWithObservers): Issue {
     return Issue.reconstitute({
       id: record.id,
       key: getCKey(record.id, record.key),
@@ -14,6 +17,7 @@ export class IssuePrismaMapper {
       type: record.type,
       assignee: record.assigneeId,
       reporter: record.reporterId,
+      observers: record.observers.map((observer) => observer.userId),
       projectId: record.projectId,
       dueDate: record.dueDate,
       createdAt: record.createdAt,
@@ -31,6 +35,7 @@ export class IssuePrismaMapper {
       type: issue.type,
       assigneeId: issue.assignee,
       reporterId: issue.reporter,
+      observers: { create: issue.observers.map((userId) => ({ userId })) },
       projectId: issue.projectId,
       dueDate: issue.dueDate,
       createdAt: issue.createdAt,

src/modules/issue/infrastructure/persistence/prisma/repositories/issue.prisma-repository.ts

@@ -2,7 +2,7 @@ import { randomUUID } from 'node:crypto';
 import { Injectable } from '@nestjs/common';
 import { PrismaAdapter } from '../../../../../../common/prisma-adapter/prisma.adapter.js';
 import { Issue } from '../../../../domain/entities/issue.entity.js';
-import { IIssueRepository } from '../../../../domain/repositories/issue.repository.interface.js';
+import { IIssueRepository, IssueUserRole } from '../../../../domain/repositories/issue.repository.interface.js';
 import { IssuePrismaMapper } from '../mappers/issue.mapper.js';
 import { IssueFindManyArgs } from '../../../../../../generated/prisma/models/Issue.js';
 import { PaginationMeta } from '../../../../../../common/interfaces/pagination-meta.interface.js';
@@ -13,9 +13,26 @@ import type { IssueFieldChange } from '../../../../domain/entities/issue-change.
 
 const FOREIGN_KEY_VIOLATION = 'P2003';
 
-/** Задача видна только своему reporter/assignee */
-function ownedByUser(userId: string) {
-  return [{ assigneeId: userId }, { reporterId: userId }];
+/** id наблюдателей подгружаются вместе с задачей — они часть сущности */
+const WITH_OBSERVERS = { observers: { select: { userId: true } } } satisfies Prisma.IssueInclude;
+
+/**
+ * Задача видна своим reporter, assignee и наблюдателям.
+ * То же правило — в visibleIssuesCte (history) и в SSE-фильтре IssueController.
+ */
+function visibleTo(userId: string): Prisma.IssueWhereInput[] {
+  return [{ assigneeId: userId }, { reporterId: userId }, { observers: { some: { userId } } }];
+}
+
+function roleFilter(userId: string, role: IssueUserRole): Prisma.IssueWhereInput {
+  switch (role) {
+    case 'assigned':
+      return { assigneeId: userId };
+    case 'reported':
+      return { reporterId: userId };
+    case 'observing':
+      return { observers: { some: { userId } } };
+  }
 }
 
 /** Видимость и фильтры, общие для списка и календаря */
@@ -24,9 +41,11 @@ function commonFilters(params: {
   status?: string[];
   assigneeId?: string;
   projectId?: string;
+  role?: IssueUserRole;
 }): Prisma.IssueWhereInput[] {
   return [
-    { OR: ownedByUser(params.userId) },
+    { OR: visibleTo(params.userId) },
+    ...(params.role ? [roleFilter(params.userId, params.role)] : []),
     ...(params.status?.length ? [{ status: { in: params.status } }] : []),
     ...(params.assigneeId ? [{ assigneeId: params.assigneeId }] : []),
     ...(params.projectId ? [{ projectId: params.projectId }] : []),
@@ -50,7 +69,8 @@ export class IssuePrismaRepository implements IIssueRepository {
 
   async findById(id: number, userId: string): Promise<Issue | null> {
     const record = await this.prisma.issue.findFirst({
-      where: { id, OR: ownedByUser(userId) },
+      where: { id, OR: visibleTo(userId) },
+      include: WITH_OBSERVERS,
     });
     return record ? IssuePrismaMapper.toDomain(record) : null;
   }
@@ -58,7 +78,8 @@ export class IssuePrismaRepository implements IIssueRepository {
   async findByCKey(ckey: string, userId: string): Promise<Issue | null> {
     const { id, key } = splitCKey(ckey);
     const record = await this.prisma.issue.findFirst({
-      where: { id, key, OR: ownedByUser(userId) },
+      where: { id, key, OR: visibleTo(userId) },
+      include: WITH_OBSERVERS,
     });
 
     return record ? IssuePrismaMapper.toDomain(record) : null;
@@ -74,6 +95,7 @@ export class IssuePrismaRepository implements IIssueRepository {
     projectId?: string;
     hasDueDate?: boolean;
     type?: string[];
+    role?: IssueUserRole;
   }): Promise<{ list: Issue[]; meta: PaginationMeta }> {
     const page = Math.max(1, params?.page);
     const limit = Math.max(1, params?.limit);
@@ -101,6 +123,7 @@ export class IssuePrismaRepository implements IIssueRepository {
     const [records, totalCount] = await this.prisma.$transaction([
       this.prisma.issue.findMany({
         ...queryArgs,
+        include: WITH_OBSERVERS,
         take: limit,
         skip: (page - 1) * limit,
         orderBy: { createdAt: 'desc' },
@@ -127,6 +150,7 @@ export class IssuePrismaRepository implements IIssueRepository {
       where: {
         AND: [...commonFilters(params), { dueDate: { gte: params.from, lt: params.to } }],
       },
+      include: WITH_OBSERVERS,
       take: Math.max(1, params.limit),
       orderBy: [{ dueDate: 'asc' }, { id: 'asc' }],
     });
@@ -137,7 +161,7 @@ export class IssuePrismaRepository implements IIssueRepository {
   async countByStatus(userId: string, projectId?: string): Promise<Array<{ status: string; count: number }>> {
     const groups = await this.prisma.issue.groupBy({
       by: ['status'],
-      where: { AND: [{ OR: ownedByUser(userId) }, ...(projectId ? [{ projectId }] : [])] },
+      where: { AND: [{ OR: visibleTo(userId) }, ...(projectId ? [{ projectId }] : [])] },
       _count: { _all: true },
     });
 
@@ -151,6 +175,7 @@ export class IssuePrismaRepository implements IIssueRepository {
       const record = await this.prisma.$transaction(async (tx) => {
         const created = await tx.issue.create({
           data: IssuePrismaMapper.toCreateInput(issue),
+          include: WITH_OBSERVERS,
         });
         await tx.issueChange.createMany({
           data: toChangeRows(created.id, changes, issue.reporter, issue.createdAt),
@@ -181,8 +206,19 @@ export class IssuePrismaRepository implements IIssueRepository {
       return;
     }
 
+    const observers = [...issue.observers];
     await this.prisma.$transaction([
       updateIssue,
+      // Наблюдатели меняются только вместе с записью observer в истории
+      ...(changes.some((change) => change.field === 'observer')
+        ? [
+            this.prisma.issueObserver.deleteMany({ where: { issueId, userId: { notIn: observers } } }),
+            this.prisma.issueObserver.createMany({
+              data: observers.map((userId) => ({ issueId, userId })),
+              skipDuplicates: true,
+            }),
+          ]
+        : []),
       this.prisma.issueChange.createMany({
         data: toChangeRows(issueId, changes, actorId, issue.updatedAt),
       }),

src/modules/issue/issue.module.ts

@@ -18,6 +18,8 @@ import { IssueUserExpanderService } from './application/services/issue-user-expa
 import { IssueAssignmentNotifierService } from './application/services/issue-assignment-notifier.service.js';
 import { GetIssueStatsUseCase } from './application/use-cases/get-issue-stats/get-issue-stats.use-case.js';
 import { ListCalendarIssuesUseCase } from './application/use-cases/list-calendar-issues/list-calendar-issues.use-case.js';
+import { UnobserveIssueUseCase } from './application/use-cases/unobserve-issue/unobserve-issue.use-case.js';
+import { IssueParticipantsService } from './application/services/issue-participants.service.js';
 
 @Module({
   imports: [PrismaModule, ProjectModule, UserModule, NotificationModule],
@@ -31,10 +33,12 @@ import { ListCalendarIssuesUseCase } from './application/use-cases/list-calendar
     DeleteIssueUseCase,
     GetIssueStatsUseCase,
     ListCalendarIssuesUseCase,
+    UnobserveIssueUseCase,
     IssueResolver,
     IssueEventsService,
     IssueUserExpanderService,
     IssueAssignmentNotifierService,
+    IssueParticipantsService,
     {
       // Domain видит только интерфейс IIssueRepository,
       // конкретную реализацию (Prisma) подставляет DI-контейнер здесь

src/modules/issue/presentation/controllers/issue.controller.ts

@@ -3,6 +3,7 @@ import {
   Body,
   Controller,
   Delete,
+  ForbiddenException,
   Get,
   HttpCode,
   HttpStatus,
@@ -42,6 +43,11 @@ import { ListCalendarIssuesUseCase } from '../../application/use-cases/list-cale
 import { ListCalendarIssuesQuery } from '../../application/use-cases/list-calendar-issues/list-calendar-issues.query.js';
 import { CalendarIssuesQueryDto } from '../dto/calendar-issues-query.dto.js';
 import { InvalidCalendarRangeException } from '../../domain/exceptions/invalid-calendar-range.exception.js';
+import { IssueEditForbiddenException } from '../../domain/exceptions/issue-edit-forbidden.exception.js';
+import { IssueProjectForbiddenException } from '../../domain/exceptions/issue-project-forbidden.exception.js';
+import { IssueObserverNotFoundException } from '../../domain/exceptions/issue-observer-not-found.exception.js';
+import { UnobserveIssueUseCase } from '../../application/use-cases/unobserve-issue/unobserve-issue.use-case.js';
+import { UnobserveIssueCommand } from '../../application/use-cases/unobserve-issue/unobserve-issue.command.js';
 
 @Controller('issues')
 export class IssueController {
@@ -54,6 +60,7 @@ export class IssueController {
     private readonly deleteIssueUseCase: DeleteIssueUseCase,
     private readonly getIssueStatsUseCase: GetIssueStatsUseCase,
     private readonly listCalendarIssuesUseCase: ListCalendarIssuesUseCase,
+    private readonly unobserveIssueUseCase: UnobserveIssueUseCase,
     private readonly issueEventsService: IssueEventsService,
   ) {}
 
@@ -71,6 +78,7 @@ export class IssueController {
           dto.assignee,
           dto.dueDate !== undefined ? new Date(dto.dueDate) : undefined,
           dto.type,
+          dto.observers,
         ),
       ),
     );
@@ -89,6 +97,7 @@ export class IssueController {
         query.assigneeId,
         query.hasDueDate,
         query.type,
+        query.role,
       ),
     );
   }
@@ -118,13 +127,15 @@ export class IssueController {
   /**
    * SSE-поток для зарегистрированных пользователей (доступ уже проверен
    * глобальным AuthGuard): уведомляет о каждой созданной, обновлённой
-   * и удалённой задаче, видимой текущему пользователю (reporter/assignee —
-   * то же правило видимости, что и в IssuePrismaRepository.ownedByUser).
+   * и удалённой задаче, видимой текущему пользователю (reporter/assignee/наблюдатель —
+   * то же правило видимости, что и в IssuePrismaRepository.visibleTo).
    */
   @Sse('events')
   issueCreatedEvents(@Session() session: UserSession): Observable<MessageEvent> {
     const isVisibleToUser = (issue: IssueDto) =>
-      issue.reporterId === session.user.id || issue.assigneeId === session.user.id;
+      issue.reporterId === session.user.id ||
+      issue.assigneeId === session.user.id ||
+      issue.observerIds.includes(session.user.id);
 
     return merge(
       this.issueEventsService.onIssueCreated().pipe(
@@ -170,6 +181,7 @@ export class IssueController {
           dto.assignee,
           dto.dueDate === undefined ? undefined : dto.dueDate === null ? null : new Date(dto.dueDate),
           dto.type,
+          dto.observers,
         ),
       ),
     );
@@ -181,6 +193,13 @@ export class IssueController {
     await this.handleErrors(() => this.deleteIssueUseCase.execute(new DeleteIssueCommand(id, session.user.id)));
   }
 
+  /** Наблюдатель отписывается от задачи сам (снять других может только reporter/assignee через PATCH) */
+  @Delete(':id/observers/me')
+  @HttpCode(HttpStatus.NO_CONTENT)
+  async unobserve(@Param('id', ParseIntPipe) id: number, @Session() session: UserSession) {
+    await this.handleErrors(() => this.unobserveIssueUseCase.execute(new UnobserveIssueCommand(id, session.user.id)));
+  }
+
   /** Транслирует доменные исключения в HTTP-ответ — это забота presentation-слоя */
   private async handleErrors<T>(fn: () => Promise<T>): Promise<T> {
     try {
@@ -189,9 +208,12 @@ export class IssueController {
       if (error instanceof IssueNotFoundException || error instanceof IssueProjectNotFoundException) {
         throw new NotFoundException(error.message);
       }
-      if (error instanceof InvalidCalendarRangeException) {
+      if (error instanceof InvalidCalendarRangeException || error instanceof IssueObserverNotFoundException) {
         throw new BadRequestException(error.message);
       }
+      if (error instanceof IssueEditForbiddenException || error instanceof IssueProjectForbiddenException) {
+        throw new ForbiddenException(error.message);
+      }
       throw error;
     }
   }

src/modules/issue/presentation/dto/create-issue.dto.ts

@@ -1,4 +1,16 @@
-import { IsDateString, IsIn, IsInt, IsNotEmpty, IsOptional, IsString, Max, MaxLength, Min } from 'class-validator';
+import {
+  ArrayMaxSize,
+  IsArray,
+  IsDateString,
+  IsIn,
+  IsInt,
+  IsNotEmpty,
+  IsOptional,
+  IsString,
+  Max,
+  MaxLength,
+  Min,
+} from 'class-validator';
 import { ISSUE_TYPE_ALIASES } from '../../domain/value-objects/issue-type.vo.js';
 
 export class CreateIssueRequestDto {
@@ -36,4 +48,11 @@ export class CreateIssueRequestDto {
   @IsOptional()
   @IsDateString()
   dueDate?: string;
+
+  /** id пользователей-наблюдателей: видят задачу и комментируют, но не редактируют */
+  @IsOptional()
+  @IsArray()
+  @ArrayMaxSize(50)
+  @IsString({ each: true })
+  observers?: string[];
 }

src/modules/issue/presentation/dto/filter-issue.dto.ts

@@ -1,4 +1,6 @@
+import { IsIn, IsOptional } from 'class-validator';
 import { BooleanDecorator, IntDecorator, StringDecorator } from '../../../../common/decorators/validators.js';
+import { ISSUE_USER_ROLES, type IssueUserRole } from '../../domain/repositories/issue.repository.interface.js';
 import { IssueStatusListDecorator, IssueTypeListDecorator } from './issue-alias-list.decorator.js';
 
 export class FilterIssueDto {
@@ -26,4 +28,9 @@ export class FilterIssueDto {
   /** false — только задачи без срока (панель «без срока» рядом с календарём), true — только со сроком */
   @BooleanDecorator({ isOptional: true })
   hasDueDate?: boolean;
+
+  /** Только задачи, где текущий пользователь исполнитель, автор или наблюдатель */
+  @IsOptional()
+  @IsIn(ISSUE_USER_ROLES)
+  role?: IssueUserRole;
 }

src/modules/issue/presentation/dto/update-issue.dto.ts

@@ -1,4 +1,15 @@
-import { IsDateString, IsIn, IsInt, IsOptional, IsString, Max, MaxLength, Min } from 'class-validator';
+import {
+  ArrayMaxSize,
+  IsArray,
+  IsDateString,
+  IsIn,
+  IsInt,
+  IsOptional,
+  IsString,
+  Max,
+  MaxLength,
+  Min,
+} from 'class-validator';
 import { ISSUE_STATUSES } from '../../domain/value-objects/issue-status.vo.js';
 import { ISSUE_TYPE_ALIASES } from '../../domain/value-objects/issue-type.vo.js';
 
@@ -33,4 +44,11 @@ export class UpdateIssueRequestDto {
   @IsOptional()
   @IsDateString()
   dueDate?: string | null;
+
+  /** id пользователей-наблюдателей (полный новый список): видят задачу и комментируют, но не редактируют */
+  @IsOptional()
+  @IsArray()
+  @ArrayMaxSize(50)
+  @IsString({ each: true })
+  observers?: string[];
 }

src/modules/issue/presentation/graphql/create-issue.input.ts

@@ -1,5 +1,17 @@
 import { Field, InputType, Int } from '@nestjs/graphql';
-import { IsDate, IsIn, IsInt, IsNotEmpty, IsOptional, IsString, Max, MaxLength, Min } from 'class-validator';
+import {
+  ArrayMaxSize,
+  IsArray,
+  IsDate,
+  IsIn,
+  IsInt,
+  IsNotEmpty,
+  IsOptional,
+  IsString,
+  Max,
+  MaxLength,
+  Min,
+} from 'class-validator';
 import { ISSUE_TYPE_ALIASES } from '../../domain/value-objects/issue-type.vo.js';
 
 @InputType()
@@ -46,4 +58,11 @@ export class CreateIssueInput {
   @IsOptional()
   @IsDate()
   dueDate?: Date;
+
+  @Field(() => [String], { nullable: true })
+  @IsOptional()
+  @IsArray()
+  @ArrayMaxSize(50)
+  @IsString({ each: true })
+  observers?: string[];
 }

src/modules/issue/presentation/graphql/issue-detail.type.ts

@@ -30,12 +30,18 @@ export class IssueDetailType {
   @Field(() => String, { nullable: true })
   reporterId: string | null;
 
+  @Field(() => [String])
+  observerIds: string[];
+
   @Field(() => UserType, { nullable: true })
   assignee: UserType | null;
 
   @Field(() => UserType, { nullable: true })
   reporter: UserType | null;
 
+  @Field(() => [UserType])
+  observers: UserType[];
+
   @Field()
   projectId: string;
 

src/modules/issue/presentation/graphql/issue.type.ts

@@ -29,6 +29,9 @@ export class IssueType {
   @Field(() => String, { nullable: true })
   reporterId: string | null;
 
+  @Field(() => [String])
+  observerIds: string[];
+
   @Field()
   projectId: string;
 

src/modules/issue/presentation/graphql/update-issue.input.ts

@@ -1,5 +1,5 @@
 import { Field, InputType, Int } from '@nestjs/graphql';
-import { IsDate, IsIn, IsInt, IsOptional, IsString, Max, MaxLength, Min } from 'class-validator';
+import { ArrayMaxSize, IsArray, IsDate, IsIn, IsInt, IsOptional, IsString, Max, MaxLength, Min } from 'class-validator';
 import { ISSUE_STATUSES } from '../../domain/value-objects/issue-status.vo.js';
 import { ISSUE_TYPE_ALIASES } from '../../domain/value-objects/issue-type.vo.js';
 
@@ -42,4 +42,11 @@ export class UpdateIssueInput {
   @IsOptional()
   @IsDate()
   dueDate?: Date | null;
+
+  @Field(() => [String], { nullable: true })
+  @IsOptional()
+  @IsArray()
+  @ArrayMaxSize(50)
+  @IsString({ each: true })
+  observers?: string[];
 }

src/modules/issue/presentation/resolvers/issue.resolver.ts

@@ -1,4 +1,4 @@
-import { BadRequestException, NotFoundException } from '@nestjs/common';
+import { BadRequestException, ForbiddenException, NotFoundException } from '@nestjs/common';
 import { Args, Int, Mutation, Query, Resolver } from '@nestjs/graphql';
 import { Session, type UserSession } from '@thallesp/nestjs-better-auth';
 import { CreateIssueUseCase } from '../../application/use-cases/create-issue/create-issue.use-case.js';
@@ -27,6 +27,12 @@ import { ListCalendarIssuesQuery } from '../../application/use-cases/list-calend
 import { CalendarIssuesDto } from '../../application/dto/calendar-issues.dto.js';
 import { InvalidCalendarRangeException } from '../../domain/exceptions/invalid-calendar-range.exception.js';
 import { PaginationMeta } from '../../../../common/interfaces/pagination-meta.interface.js';
+import { IssueEditForbiddenException } from '../../domain/exceptions/issue-edit-forbidden.exception.js';
+import { IssueProjectForbiddenException } from '../../domain/exceptions/issue-project-forbidden.exception.js';
+import { IssueObserverNotFoundException } from '../../domain/exceptions/issue-observer-not-found.exception.js';
+import { UnobserveIssueUseCase } from '../../application/use-cases/unobserve-issue/unobserve-issue.use-case.js';
+import { UnobserveIssueCommand } from '../../application/use-cases/unobserve-issue/unobserve-issue.command.js';
+import { ISSUE_USER_ROLES, type IssueUserRole } from '../../domain/repositories/issue.repository.interface.js';
 
 @Resolver(() => IssueType)
 export class IssueResolver {
@@ -38,6 +44,7 @@ export class IssueResolver {
     private readonly updateIssueUseCase: UpdateIssueUseCase,
     private readonly deleteIssueUseCase: DeleteIssueUseCase,
     private readonly listCalendarIssuesUseCase: ListCalendarIssuesUseCase,
+    private readonly unobserveIssueUseCase: UnobserveIssueUseCase,
   ) {}
 
   @Query(() => IssueDetailType, { name: 'issue' })
@@ -58,7 +65,12 @@ export class IssueResolver {
     @Args('projectId', { type: () => String, nullable: true }) projectId?: string,
     @Args('hasDueDate', { type: () => Boolean, nullable: true }) hasDueDate?: boolean,
     @Args('type', { type: () => [String], nullable: true }) type?: string[],
+    @Args('role', { type: () => String, nullable: true }) role?: string,
   ): Promise<{ list: IssueWithUsersDto[]; meta: PaginationMeta }> {
+    if (role && !ISSUE_USER_ROLES.includes(role as IssueUserRole)) {
+      throw new BadRequestException(`role must be one of: ${ISSUE_USER_ROLES.join(', ')}`);
+    }
+
     return this.listIssuesUseCase.execute(
       new ListIssuesQuery(
         limit,
@@ -70,6 +82,7 @@ export class IssueResolver {
         undefined,
         hasDueDate ?? undefined,
         type ?? undefined,
+        (role as IssueUserRole | undefined) ?? undefined,
       ),
     );
   }
@@ -105,6 +118,7 @@ export class IssueResolver {
           input.assignee,
           input.dueDate,
           input.type,
+          input.observers,
         ),
       ),
     );
@@ -128,6 +142,7 @@ export class IssueResolver {
           input.assignee,
           input.dueDate,
           input.type,
+          input.observers ?? undefined,
         ),
       ),
     );
@@ -139,6 +154,13 @@ export class IssueResolver {
     return true;
   }
 
+  /** Наблюдатель отписывается от задачи сам */
+  @Mutation(() => Boolean, { name: 'unobserveIssue' })
+  async unobserve(@Args('id', { type: () => Int }) id: number, @Session() session: UserSession): Promise<boolean> {
+    await this.handleErrors(() => this.unobserveIssueUseCase.execute(new UnobserveIssueCommand(id, session.user.id)));
+    return true;
+  }
+
   /** Транслирует доменные исключения в GraphQL-ошибку — это забота presentation-слоя */
   private async handleErrors<T>(fn: () => Promise<T>): Promise<T> {
     try {
@@ -147,9 +169,12 @@ export class IssueResolver {
       if (error instanceof IssueNotFoundException || error instanceof IssueProjectNotFoundException) {
         throw new NotFoundException(error.message);
       }
-      if (error instanceof InvalidCalendarRangeException) {
+      if (error instanceof InvalidCalendarRangeException || error instanceof IssueObserverNotFoundException) {
         throw new BadRequestException(error.message);
       }
+      if (error instanceof IssueEditForbiddenException || error instanceof IssueProjectForbiddenException) {
+        throw new ForbiddenException(error.message);
+      }
       throw error;
     }
   }

src/modules/project/domain/repositories/project.repository.interface.ts

@@ -4,6 +4,12 @@ import { PaginationMeta } from '../../../../common/interfaces/pagination-meta.in
 /** DI-токен, т.к. интерфейсы стираются при компиляции TS */
 export const PROJECT_REPOSITORY = Symbol('PROJECT_REPOSITORY');
 
+/**
+ * Роль пользователя в проекте. OWNER и MEMBER создают задачи,
+ * OBSERVER только видит проект (он наблюдатель отдельных задач).
+ */
+export type ProjectRole = 'OWNER' | 'MEMBER' | 'OBSERVER';
+
 export interface IProjectRepository {
   /** Проект виден владельцу и участникам проекта (ProjectMember) */
   findById(id: string, userId: string): Promise<Project | null>;
@@ -11,6 +17,11 @@ export interface IProjectRepository {
   create(project: Project): Promise<Project>;
   update(project: Project): Promise<void>;
   delete(id: string): Promise<void>;
-  /** Добавляет пользователя в участники проекта, если он ещё не владелец/участник */
-  addMember(projectId: string, userId: string): Promise<void>;
+  /** Роль пользователя в проекте; null — проект ему не виден (или не существует) */
+  findRole(projectId: string, userId: string): Promise<ProjectRole | null>;
+  /**
+   * Добавляет пользователя в участники проекта. Роль только повышается:
+   * OBSERVER становится MEMBER, но MEMBER не понижается до OBSERVER.
+   */
+  addMember(projectId: string, userId: string, role: Exclude<ProjectRole, 'OWNER'>): Promise<void>;
 }

src/modules/project/infrastructure/persistence/prisma/repositories/project.prisma-repository.ts

@@ -1,7 +1,7 @@
 import { Injectable } from '@nestjs/common';
 import { PrismaAdapter } from '../../../../../../common/prisma-adapter/prisma.adapter.js';
 import { Project } from '../../../../domain/entities/project.entity.js';
-import { IProjectRepository } from '../../../../domain/repositories/project.repository.interface.js';
+import { IProjectRepository, ProjectRole } from '../../../../domain/repositories/project.repository.interface.js';
 import { ProjectPrismaMapper } from '../mappers/project.mapper.js';
 import { PaginationMeta } from '../../../../../../common/interfaces/pagination-meta.interface.js';
 import { Prisma } from '../../../../../../generated/prisma/client.js';
@@ -69,11 +69,21 @@ export class ProjectPrismaRepository implements IProjectRepository {
     await this.prisma.project.delete({ where: { id } });
   }
 
-  async addMember(projectId: string, userId: string): Promise<void> {
+  async findRole(projectId: string, userId: string): Promise<ProjectRole | null> {
+    const record = await this.prisma.project.findFirst({
+      where: { id: projectId, ...this.accessibleBy(userId) },
+      select: { ownerId: true, members: { where: { userId }, select: { role: true } } },
+    });
+    if (!record) return null;
+    if (record.ownerId === userId) return 'OWNER';
+    return record.members[0]?.role ?? null;
+  }
+
+  async addMember(projectId: string, userId: string, role: Exclude<ProjectRole, 'OWNER'>): Promise<void> {
     await this.prisma.projectMember.upsert({
       where: { projectId_userId: { projectId, userId } },
-      create: { projectId, userId },
-      update: {},
+      create: { projectId, userId, role },
+      update: role === 'MEMBER' ? { role } : {},
     });
   }