refactor: enforce enum machine codes

Use owner enums for error and T-Bank protocol values with ESLint regression checks.

Preserve open wire fallbacks and keep protocol imports independent of DI and Prisma.

Verified npm ci, verify, 226 unit tests, 262 isolated e2e tests and unchanged OpenAPI.

.ai/architecture.md

@@ -160,10 +160,11 @@ HTTP/e2e naming и расположение — в [Testing](conventions/testing
 
 `*.module.ts` задаёт DI boundary; `*.api.ts` перечисляет используемые другими
 модулями providers, функции и типы. Внешний production import идёт через этот
-API или файл Nest module. Чистые `integrations/tbank/decimal.ts` и
+API или файл Nest module. Чистые `integrations/tbank/decimal.ts`,
+`integrations/tbank/tbank-protocol.ts`, `integrations/tbank/tbank-error-code.ts` и
 `modules/investments/operations/domain/operations-sync-plan.ts` — отдельные
-публичные входы для protobuf conversion и interval rules: импорт расчётов
-не загружает DI/Prisma.
+публичные входы для protobuf conversion, protocol/error vocabulary и interval
+rules: импорт этих значений и расчётов не загружает DI/Prisma.
 Внутри модуля используй прямые локальные импорты.
 Tests могут импортировать внутренний owner для проверки поведения и mocks.
 Новый export требует текущего потребителя; controller и persistence остаются
@@ -251,7 +252,12 @@ OpenAPI enum metadata и runtime validation должны читать тот ж
 Исключения для индексов, default values, enum/type declarations и readonly
 properties заданы в ESLint config. Test fixtures/expected values остаются inline,
 остальные lint правила продолжают действовать. Numeric policy получает предметное имя и единицы;
-semantic magic strings проверяются conventions/review без нового инструмента.
+Machine codes и protocol values задаются строковыми enum у владельца.
+`no-restricted-syntax` запрещает inline-коды и значения известных protocol families
+в production TS; `no-unsafe-enum-comparison` проверяет сравнения enum.
+Внешние открытые строки проверяются на boundary без cast и без потери unknown fallback.
+Tests сохраняют независимые literal wire assertions; обычный текст и env keys
+не считаются кодами. Новые словари требуют проверки владельца и расширения selectors.
 
 ## Logging
 

.ai/conventions/engineering.md

@@ -29,7 +29,8 @@ owner и 1–3 примера. Код показывает механизм; с
 ## Domain values
 
 Finite business vocabulary принадлежит одному domain/module/entity owner.
-Переиспользуй его symbols; для нового словаря без аналога — `as const` + union.
+Переиспользуй его symbols; для machine codes и protocol values используй
+строковые `enum`, для структуры с разными payload — discriminated union.
 Сохраняй wire values; generated/external enums не переписывай вручную.
 Numeric policy называй по смыслу и единицам. Индексы, `Math.max(value, 0)` и
 обычные labels не выноси в constants без semantic benefit.

.ai/conventions/integrations.md

@@ -22,7 +22,9 @@ RPC, credentials/access и resilience. Эти владельцы не объед
 
 Преобразование provider records происходит на boundary: например,
 `tbank-portfolio.mapper.ts` и `bond-money.mapper.ts`; protobuf decimal helper
-остаётся отдельным чистым входом integration. Domain получает внутренние
+остаётся отдельным чистым входом integration. `tbank-protocol.ts` и
+`tbank-error-code.ts` также импортируются напрямую: их enums и guards
+не должны загружать DI/Prisma через service exports. Domain получает внутренние
 значения и не импортирует gRPC/SDK types. Не добавляй новый adapter на каждый
 client или mapper для простого копирования полей. Даты/units/nano разбираются
 на границе клиента/его mapping, а не становятся моделью чистых расчётов.

eslint.config.mjs

@@ -107,4 +107,47 @@ export default defineConfig(
       'jest/expect-expect': ['error', { assertFunctionNames: ['expect', '**.expect'] }],
     },
   },
+  {
+    files: [
+      'src/**/*.ts',
+    ],
+    ignores: [
+      '**/*.spec.ts',
+      'test/**/*.ts',
+    ],
+    rules: {
+      'no-restricted-syntax': [
+        'error',
+        {
+          selector: 'Literal[value=/^(?:(?:INSTRUMENT_ID_TYPE|INSTRUMENT_TYPE|OPERATION_STATE|OPERATION_TYPE|ACCOUNT_STATUS|ACCOUNT_TYPE|CANDLE_INTERVAL|COUPON_TYPE|BANK|INVALID)_[A-Z0-9]+(?:_[A-Z0-9]+)*|[A-Z][A-Z0-9_]*_(?:ERROR|UNAVAILABLE|NOT_FOUND|NOT_CONNECTED|CONFLICT|AMBIGUOUS|REGISTERED)|P[0-9]{4}|UNAUTHORIZED|FORBIDDEN|BAD_REQUEST|NOT_FOUND|UNSUPPORTED_MEDIA_TYPE)$/]:not(TSEnumMember > Literal)',
+          message: 'Use the owning enum member for machine codes and protocol values.',
+        },
+        {
+          selector: 'TemplateElement[value.cooked=/^(?:(?:INSTRUMENT_ID_TYPE|INSTRUMENT_TYPE|OPERATION_STATE|OPERATION_TYPE|ACCOUNT_STATUS|ACCOUNT_TYPE|CANDLE_INTERVAL|COUPON_TYPE|BANK|INVALID)_[A-Z0-9]+(?:_[A-Z0-9]+)*|[A-Z][A-Z0-9_]*_(?:ERROR|UNAVAILABLE|NOT_FOUND|NOT_CONNECTED|CONFLICT|AMBIGUOUS|REGISTERED)|P[0-9]{4}|UNAUTHORIZED|FORBIDDEN|BAD_REQUEST|NOT_FOUND|UNSUPPORTED_MEDIA_TYPE)$/]:not(TSEnumMember TemplateElement)',
+          message: 'Use the owning enum member instead of a template machine code.',
+        },
+        {
+          selector: 'Property:matches([key.name=/^(code|errorCode|idType|instrumentKind)$/], [key.value=/^(code|errorCode|idType|instrumentKind)$/]) > Literal.value[value=type(string)]',
+          message: 'Use an enum member instead of an inline code or protocol value.',
+        },
+        {
+          selector: 'Property:matches([key.name=/^(code|errorCode|idType|instrumentKind)$/], [key.value=/^(code|errorCode|idType|instrumentKind)$/]) > TemplateLiteral.value',
+          message: 'Use an enum member instead of constructing a code or protocol value.',
+        },
+        {
+          selector: 'Property[computed=false][key.name=/^(OPERATION_TYPE|ACCOUNT_TYPE)_/]',
+          message: 'Use a computed enum member as the protocol mapping key.',
+        },
+        {
+          selector: 'BinaryExpression:has(> :matches(MemberExpression[property.name=/^(code|errorCode)$/], Identifier[name=/^(code|errorCode)$/])) > Literal[value=type(string)]',
+          message: 'Compare codes with their enum members, not string literals.',
+        },
+        {
+          selector: 'PropertyDefinition[definite=true], VariableDeclarator[definite=true]',
+          message: 'Definite assignment assertions are forbidden. Initialize owned values; use declare only for externally populated DTO fields.',
+        },
+      ],
+      '@typescript-eslint/no-unsafe-enum-comparison': 'error',
+    },
+  },
 );

src/common/decorators/api-safe-error-response.decorator.ts

@@ -7,11 +7,13 @@ import {
   getSchemaPath,
 } from '@nestjs/swagger';
 
+import { HttpErrorCode } from '../error-code';
+
 export class ProblemDetailsDto {
   @ApiProperty({ example: 401 })
   declare status: number;
 
-  @ApiProperty({ example: 'UNAUTHORIZED' })
+  @ApiProperty({ example: HttpErrorCode.Unauthorized })
   declare code: string;
 
   // eslint-disable-next-line @darraghor/nestjs-typed/api-property-returning-array-should-set-array -- Raw OpenAPI items schema already declares type: array.

src/common/error-code.ts

@@ -0,0 +1,8 @@
+export enum HttpErrorCode {
+  BadRequest = 'BAD_REQUEST',
+  InternalServerError = 'INTERNAL_SERVER_ERROR',
+  NotFound = 'NOT_FOUND',
+  Unauthorized = 'UNAUTHORIZED',
+  UnsupportedMediaType = 'UNSUPPORTED_MEDIA_TYPE',
+  ValidationError = 'VALIDATION_ERROR',
+}

src/common/filters/http-exception.filter.ts

@@ -9,6 +9,8 @@ import {
   ValidationError,
 } from '@nestjs/common';
 
+import { HttpErrorCode } from '../error-code';
+
 @Catch()
 export class HttpExceptionFilter implements ExceptionFilter {
   catch(exception: unknown, host: ArgumentsHost): void {
@@ -25,7 +27,7 @@ export class HttpExceptionFilter implements ExceptionFilter {
       (payload as { message?: unknown })?.message,
     );
     const code = isValidation
-      ? 'VALIDATION_ERROR'
+      ? HttpErrorCode.ValidationError
       : this.codeFor(status, payload);
     response.locals ??= {};
     response.locals.publicErrorCode = code;
@@ -53,12 +55,12 @@ export class HttpExceptionFilter implements ExceptionFilter {
     return (
       // eslint-disable-next-line security/detect-object-injection -- The lookup key is a numeric HTTP status, never a property name from the request.
       {
-        400: 'BAD_REQUEST',
-        401: 'UNAUTHORIZED',
-        404: 'NOT_FOUND',
-        415: 'UNSUPPORTED_MEDIA_TYPE',
-        500: 'INTERNAL_SERVER_ERROR',
-      }[status] ?? 'INTERNAL_SERVER_ERROR'
+        400: HttpErrorCode.BadRequest,
+        401: HttpErrorCode.Unauthorized,
+        404: HttpErrorCode.NotFound,
+        415: HttpErrorCode.UnsupportedMediaType,
+        500: HttpErrorCode.InternalServerError,
+      }[status] ?? HttpErrorCode.InternalServerError
     );
   }
 

src/integrations/moex/moex.client.ts

@@ -1,6 +1,8 @@
 import { Injectable, ServiceUnavailableException } from '@nestjs/common';
 import { constants as httpStatus } from 'node:http2';
 
+enum MoexErrorCode { Unavailable = 'MOEX_UNAVAILABLE' }
+
 const MIN_PRICE_PERCENT_EXCLUSIVE = 0;
 const FIRST_PAGE_OFFSET = 0;
 const EXPECTED_CURSOR_ROWS = 1;
@@ -152,7 +154,7 @@ export class MoexClient {
         pageSize === EMPTY_PAGE_SIZE ||
         current.length !== Math.min(pageSize, total - start)
       ) {
-        throw new ServiceUnavailableException({ code: 'MOEX_UNAVAILABLE' });
+        throw new ServiceUnavailableException({ code: MoexErrorCode.Unavailable });
       }
       if (index + pageSize >= total) return rows;
       start = index + pageSize;
@@ -172,22 +174,22 @@ export class MoexClient {
       }
       return body as IssResponse;
     } catch {
-      throw new ServiceUnavailableException({ code: 'MOEX_UNAVAILABLE' });
+      throw new ServiceUnavailableException({ code: MoexErrorCode.Unavailable });
     }
   }
 }
 
 function parseRows(block: IssBlock | undefined): Record<string, unknown>[] {
   if (!Array.isArray(block?.columns) || !Array.isArray(block?.data)) {
-    throw new ServiceUnavailableException({ code: 'MOEX_UNAVAILABLE' });
+    throw new ServiceUnavailableException({ code: MoexErrorCode.Unavailable });
   }
   const columns = block.columns;
   if (!columns.every((column) => typeof column === 'string')) {
-    throw new ServiceUnavailableException({ code: 'MOEX_UNAVAILABLE' });
+    throw new ServiceUnavailableException({ code: MoexErrorCode.Unavailable });
   }
   return block.data.map((values) => {
     if (!Array.isArray(values) || values.length !== columns.length) {
-      throw new ServiceUnavailableException({ code: 'MOEX_UNAVAILABLE' });
+      throw new ServiceUnavailableException({ code: MoexErrorCode.Unavailable });
     }
     return Object.fromEntries(
       // eslint-disable-next-line security/detect-object-injection -- Keys are fixed MOEX block names; row indexes come from the validated columns array.

src/integrations/ncr/ncr-ratings.client.ts

@@ -4,6 +4,8 @@ import { LRUCache } from 'lru-cache';
 
 import { ISO_DATE_LENGTH, ISO_DATE_START } from '../../common/time';
 
+enum NcrErrorCode { Unavailable = 'NCR_UNAVAILABLE' }
+
 const EXPECTED_REGISTRY_TABLES = 1;
 const RATING_COLUMN = 2;
 
@@ -41,7 +43,7 @@ export class NcrRatingsClient {
         if (this.cache.get('registry') === pending) {
           this.cache.set('registry', pending, { ttl: 60_000 });
         }
-        throw new ServiceUnavailableException({ code: 'NCR_UNAVAILABLE' });
+        throw new ServiceUnavailableException({ code: NcrErrorCode.Unavailable });
       });
       this.cache.set('registry', pending);
     }

src/integrations/tbank/instrument-metadata.repository.ts

@@ -11,6 +11,7 @@ import type { TbankSyncAttempt } from './tbank-access.service';
 import type { TbankInstrument } from './tbank.client';
 
 import { PrismaService } from '../../prisma/prisma.service';
+import { TbankErrorCode } from './tbank-error-code';
 import { tbankSourceTtlMs } from './tbank-source.policy';
 
 const FIRST_BATCH_OFFSET = 0;
@@ -276,7 +277,7 @@ export class InstrumentMetadataRepository {
       },
       data: {
         state: success ? 'complete' : 'failed',
-        errorCode: success ? null : 'TBANK_UNAVAILABLE',
+        errorCode: success ? null : TbankErrorCode.Unavailable,
       },
     });
     if (success) {
@@ -286,7 +287,7 @@ export class InstrumentMetadataRepository {
           state: 'running',
           connection: { invalidToken: true },
         },
-        data: { state: 'failed', errorCode: 'INVALID_TBANK_TOKEN' },
+        data: { state: 'failed', errorCode: TbankErrorCode.InvalidToken },
       });
     }
   }

src/integrations/tbank/instrument-metadata.service.ts

@@ -12,6 +12,7 @@ import {
   TbankAccessService,
   type TbankSyncAttempt,
 } from './tbank-access.service';
+import { isTbankErrorCode, TbankErrorCode } from './tbank-error-code';
 import { TbankClient, type TbankInstrument } from './tbank.client';
 export { metadataKey } from './instrument-metadata.repository';
 export type { MetadataIdentity } from './instrument-metadata.repository';
@@ -131,7 +132,7 @@ export class InstrumentMetadataService {
                 if (
                   !identity.figi ||
                   (error instanceof Error &&
-                    error.message === 'INVALID_TBANK_TOKEN')
+                    isTbankErrorCode(error.message, TbankErrorCode.InvalidToken))
                 ) {
                   throw error;
                 }
@@ -191,11 +192,11 @@ export class InstrumentMetadataService {
             );
           }
         } catch (error) {
-          if (error instanceof Error && error.message === 'INVALID_TBANK_TOKEN') {
+          if (error instanceof Error && isTbankErrorCode(error.message, TbankErrorCode.InvalidToken)) {
             await this.access.rejectMembershipToken(attempt);
           } else {
             this.logger.event('warn', 'instrument-metadata.failed', {
-              code: 'TBANK_UNAVAILABLE',
+              code: TbankErrorCode.Unavailable,
             });
           }
         }
@@ -209,7 +210,7 @@ export class InstrumentMetadataService {
       }
     } catch {
       this.logger.event('error', 'instrument-metadata.persistence-failed', {
-        code: 'TBANK_UNAVAILABLE',
+        code: TbankErrorCode.Unavailable,
       });
       this.active.clear();
       this.producers.clear();

src/integrations/tbank/tbank-access.service.ts

@@ -10,6 +10,7 @@ import type { TbankAccount } from './tbank.client';
 
 import { PrismaService } from '../../prisma/prisma.service';
 import { supportedTbankAccounts } from './tbank-account.policy';
+import { TbankErrorCode } from './tbank-error-code';
 import { tbankSourceNeedsRefresh } from './tbank-source.policy';
 import { TbankTokenService } from './tbank-token.service';
 
@@ -103,7 +104,7 @@ export class TbankAccessService {
         state: 'running',
         connection: { invalidToken: false },
       },
-      data: { state: 'failed', errorCode: 'TBANK_UNAVAILABLE' },
+      data: { state: 'failed', errorCode: TbankErrorCode.Unavailable },
     });
     return result.count === EXPECTED_UPDATED_CONNECTIONS;
   }
@@ -205,7 +206,7 @@ export class TbankAccessService {
     return this.prisma.$transaction(async (tx) => {
       const claimed = await tx.tbankSyncWork.updateMany({
         where: { ...attempt, state: 'running' },
-        data: { state: 'failed', errorCode: 'INVALID_TBANK_TOKEN' },
+        data: { state: 'failed', errorCode: TbankErrorCode.InvalidToken },
       });
       if (!claimed.count) return false;
       await tx.tbankConnection.update({
@@ -236,10 +237,10 @@ export class TbankAccessService {
       },
     });
     if (!connection) {
-      throw new ConflictException({ code: 'TBANK_NOT_CONNECTED' });
+      throw new ConflictException({ code: TbankErrorCode.NotConnected });
     }
     if (connection.invalidToken) {
-      throw new BadRequestException({ code: 'INVALID_TBANK_TOKEN' });
+      throw new BadRequestException({ code: TbankErrorCode.InvalidToken });
     }
     if (
       connection.membershipAt &&

src/integrations/tbank/tbank-account.policy.ts

@@ -1,14 +1,15 @@
 import { ISO_DATE_LENGTH, ISO_DATE_START, MILLISECONDS_PER_SECOND } from '../../common/time';
+import { TbankAccountType } from './tbank-protocol';
 import { TbankAccount } from './tbank.client';
 
 const accountTypes = {
-  ACCOUNT_TYPE_TINKOFF: { type: 'BROKERAGE', name: 'Брокерский счет' },
-  ACCOUNT_TYPE_TINKOFF_IIS: {
+  [TbankAccountType.Tinkoff]: { type: 'BROKERAGE', name: 'Брокерский счет' },
+  [TbankAccountType.TinkoffIis]: {
     type: 'INDIVIDUAL_INVESTMENT',
     name: 'ИИС',
   },
-  ACCOUNT_TYPE_INVEST_BOX: { type: 'INVEST_BOX', name: 'Инвесткопилка' },
-  ACCOUNT_TYPE_INVEST_FUND: {
+  [TbankAccountType.InvestBox]: { type: 'INVEST_BOX', name: 'Инвесткопилка' },
+  [TbankAccountType.InvestFund]: {
     type: 'MONEY_MARKET_FUND',
     name: 'Фонд денежного рынка',
   },

src/integrations/tbank/tbank-error-code.ts

@@ -0,0 +1,10 @@
+export enum TbankErrorCode {
+  InvalidToken = 'INVALID_TBANK_TOKEN',
+  NotConnected = 'TBANK_NOT_CONNECTED',
+  Unavailable = 'TBANK_UNAVAILABLE',
+}
+
+// Error messages and persisted codes cross an open string boundary.
+export function isTbankErrorCode(value: unknown, expected: TbankErrorCode): boolean {
+  return value === expected;
+}

src/integrations/tbank/tbank-membership.service.ts

@@ -6,6 +6,7 @@ import {
   TbankAccessService,
   type TbankSyncAttempt,
 } from './tbank-access.service';
+import { isTbankErrorCode, TbankErrorCode } from './tbank-error-code';
 import { TbankClient } from './tbank.client';
 
 @Injectable()
@@ -37,7 +38,7 @@ export class TbankMembershipService {
           .catch(() =>
             this.logger.event('error', 'tbank.membership.persistence_failed', {
               userId,
-              code: 'TBANK_UNAVAILABLE',
+              code: TbankErrorCode.Unavailable,
             }),
           )
           .finally(() => this.active.delete(attemptId));
@@ -62,7 +63,7 @@ export class TbankMembershipService {
     } catch (error) {
       await this.access.failMembership(
         attempt,
-        error instanceof Error && error.message === 'INVALID_TBANK_TOKEN',
+        error instanceof Error && isTbankErrorCode(error.message, TbankErrorCode.InvalidToken),
       );
     }
   }

src/integrations/tbank/tbank-protocol.spec.ts

@@ -0,0 +1,42 @@
+import { loadSync } from '@grpc/proto-loader';
+import { join } from 'node:path';
+
+import { isTbankErrorCode, TbankErrorCode } from './tbank-error-code';
+import {
+  InstrumentIdType,
+  isTbankProtocolValue,
+  TbankAccountStatus,
+  TbankAccountType,
+  TbankCandleInterval,
+  TbankCouponType,
+  TbankInstrumentType,
+  TbankOperationState,
+  TbankOperationType,
+} from './tbank-protocol';
+
+it('uses the string enum values declared by the vendored protocol', () => {
+  const directory = join(__dirname, 'proto/contracts');
+  const definitions = loadSync(['users.proto', 'instruments.proto', 'operations.proto', 'marketdata.proto'].map((file) => join(directory, file)), { includeDirs: [directory], enums: String });
+  for (const [name, values] of Object.entries({
+    InstrumentIdType,
+    InstrumentType: TbankInstrumentType,
+    AccountStatus: TbankAccountStatus,
+    AccountType: TbankAccountType,
+    CandleInterval: TbankCandleInterval,
+    CouponType: TbankCouponType,
+    OperationState: TbankOperationState,
+    OperationType: TbankOperationType,
+  })) {
+    const definition = definitions[`tinkoff.public.invest.api.contract.v1.${name}`];
+    expect(definition).toHaveProperty('format', 'Protocol Buffer 3 EnumDescriptorProto');
+    const descriptor = definition as { type: { value: { name: string }[] } };
+    expect(descriptor.type.value.map((member) => member.name)).toEqual(expect.arrayContaining(Object.values(values)));
+  }
+});
+
+it('recognizes supported wire values without accepting unknown ones', () => {
+  expect(isTbankProtocolValue('OPERATION_STATE_EXECUTED', TbankOperationState.Executed)).toBe(true);
+  expect(isTbankProtocolValue('NEW_UPSTREAM_STATE', TbankOperationState.Executed)).toBe(false);
+  expect(isTbankErrorCode('INVALID_TBANK_TOKEN', TbankErrorCode.InvalidToken)).toBe(true);
+  expect(isTbankErrorCode('NEW_UPSTREAM_ERROR', TbankErrorCode.InvalidToken)).toBe(false);
+});

src/integrations/tbank/tbank-protocol.ts

@@ -0,0 +1,70 @@
+// String wire values for the protocol subset used by this integration.
+// proto-loader decodes enums as strings; vendor contracts remain the source.
+export enum InstrumentIdType {
+  Figi = 'INSTRUMENT_ID_TYPE_FIGI',
+  Uid = 'INSTRUMENT_ID_TYPE_UID',
+}
+
+export enum TbankInstrumentType {
+  Bond = 'INSTRUMENT_TYPE_BOND',
+  Share = 'INSTRUMENT_TYPE_SHARE',
+}
+
+export enum TbankAccountStatus {
+  Open = 'ACCOUNT_STATUS_OPEN',
+}
+
+export enum TbankAccountType {
+  InvestBox = 'ACCOUNT_TYPE_INVEST_BOX',
+  InvestFund = 'ACCOUNT_TYPE_INVEST_FUND',
+  Tinkoff = 'ACCOUNT_TYPE_TINKOFF',
+  TinkoffIis = 'ACCOUNT_TYPE_TINKOFF_IIS',
+}
+
+export enum TbankCandleInterval {
+  Day = 'CANDLE_INTERVAL_DAY',
+}
+
+export enum TbankOperationState {
+  Executed = 'OPERATION_STATE_EXECUTED',
+}
+
+export enum TbankCouponType {
+  Floating = 'COUPON_TYPE_FLOATING',
+  Unspecified = 'COUPON_TYPE_UNSPECIFIED',
+}
+
+export enum TbankOperationType {
+  BondTax = 'OPERATION_TYPE_BOND_TAX',
+  BrokerFee = 'OPERATION_TYPE_BROKER_FEE',
+  Buy = 'OPERATION_TYPE_BUY',
+  BuyCard = 'OPERATION_TYPE_BUY_CARD',
+  BuyMargin = 'OPERATION_TYPE_BUY_MARGIN',
+  Coupon = 'OPERATION_TYPE_COUPON',
+  DivExt = 'OPERATION_TYPE_DIV_EXT',
+  Dividend = 'OPERATION_TYPE_DIVIDEND',
+  DividendTax = 'OPERATION_TYPE_DIVIDEND_TAX',
+  DividendTransfer = 'OPERATION_TYPE_DIVIDEND_TRANSFER',
+  Input = 'OPERATION_TYPE_INPUT',
+  InputSecurities = 'OPERATION_TYPE_INPUT_SECURITIES',
+  MarginFee = 'OPERATION_TYPE_MARGIN_FEE',
+  Output = 'OPERATION_TYPE_OUTPUT',
+  OutputSecurities = 'OPERATION_TYPE_OUTPUT_SECURITIES',
+  Sell = 'OPERATION_TYPE_SELL',
+  SellCard = 'OPERATION_TYPE_SELL_CARD',
+  SellMargin = 'OPERATION_TYPE_SELL_MARGIN',
+  ServiceFee = 'OPERATION_TYPE_SERVICE_FEE',
+  SuccessFee = 'OPERATION_TYPE_SUCCESS_FEE',
+  Tax = 'OPERATION_TYPE_TAX',
+  TransBsBs = 'OPERATION_TYPE_TRANS_BS_BS',
+  TransIisBs = 'OPERATION_TYPE_TRANS_IIS_BS',
+  Unspecified = 'OPERATION_TYPE_UNSPECIFIED',
+}
+
+// Provider responses may contain values newer than our supported protocol subset.
+export function isTbankProtocolValue(
+  value: unknown,
+  expected: TbankCouponType | TbankInstrumentType | TbankOperationState | TbankOperationType,
+): boolean {
+  return value === expected;
+}

src/integrations/tbank/tbank-token.service.ts

@@ -2,6 +2,7 @@ import { BadRequestException, Injectable } from '@nestjs/common';
 import { ConfigService } from '@nestjs/config';
 
 import { Environment } from '../../config/env.validation';
+import { isTbankErrorCode, TbankErrorCode } from './tbank-error-code';
 import { TbankCrypto } from './tbank.crypto';
 
 @Injectable()
@@ -26,8 +27,8 @@ export class TbankTokenService {
     try {
       return await operation();
     } catch (error) {
-      if (error instanceof Error && error.message === 'INVALID_TBANK_TOKEN') {
-        throw new BadRequestException({ code: 'INVALID_TBANK_TOKEN' });
+      if (error instanceof Error && isTbankErrorCode(error.message, TbankErrorCode.InvalidToken)) {
+        throw new BadRequestException({ code: TbankErrorCode.InvalidToken });
       }
       throw error;
     }

src/integrations/tbank/tbank.client.spec.ts

@@ -1,6 +1,7 @@
 import { status } from '@grpc/grpc-js';
 import { NotFoundException, ServiceUnavailableException } from '@nestjs/common';
 
+import { TbankOperationState } from './tbank-protocol';
 import { TbankClient } from './tbank.client';
 
 describe('TbankClient operations', () => {
@@ -10,7 +11,7 @@ describe('TbankClient operations', () => {
     to: { seconds: '2' },
     cursor: 'cursor',
     limit: 10,
-    state: 'OPERATION_STATE_EXECUTED' as const,
+    state: TbankOperationState.Executed,
   };
 
   it('passes a cursor operations request to OperationsService', async () => {

src/integrations/tbank/tbank.client.ts

@@ -29,6 +29,14 @@ import type {
 import { StructuredLogger } from '../../common/logging/structured-logger.service';
 import { MILLISECONDS_PER_SECOND } from '../../common/time';
 import { Environment } from '../../config/env.validation';
+import { TbankErrorCode } from './tbank-error-code';
+import {
+  InstrumentIdType,
+  TbankAccountStatus,
+  TbankCandleInterval,
+  TbankInstrumentType,
+  TbankOperationState,
+} from './tbank-protocol';
 
 const INITIAL_REQUEST_COUNT = 0;
 const MIN_RATE_DELAY_MS = 1;
@@ -115,7 +123,7 @@ export type TbankOperationsByCursorRequest = {
   from?: TbankTimestamp;
   instrumentId?: string;
   limit?: number;
-  state: 'OPERATION_STATE_EXECUTED';
+  state: TbankOperationState.Executed;
   to?: TbankTimestamp;
 };
 export type TbankOperationsByCursorResponse = {
@@ -256,7 +264,7 @@ export class TbankClient {
       token,
       this.users,
       'getAccounts',
-      { status: 'ACCOUNT_STATUS_OPEN' },
+      { status: TbankAccountStatus.Open },
     ).then((response) => response.accounts ?? []);
   }
 
@@ -279,14 +287,14 @@ export class TbankClient {
     token: string,
     figi: string,
   ): Promise<null | TbankInstrument> {
-    return this.getInstrument(token, 'INSTRUMENT_ID_TYPE_FIGI', figi);
+    return this.getInstrument(token, InstrumentIdType.Figi, figi);
   }
 
   getInstrumentByUid(
     token: string,
     instrumentUid: string,
   ): Promise<null | TbankInstrument> {
-    return this.getInstrument(token, 'INSTRUMENT_ID_TYPE_UID', instrumentUid);
+    return this.getInstrument(token, InstrumentIdType.Uid, instrumentUid);
   }
 
   getDividends(
@@ -314,7 +322,7 @@ export class TbankClient {
       'findInstrument',
       {
         query,
-        instrumentKind: 'INSTRUMENT_TYPE_SHARE',
+        instrumentKind: TbankInstrumentType.Share,
       },
     ).then((response) => response.instruments ?? []);
   }
@@ -326,7 +334,7 @@ export class TbankClient {
       'findInstrument',
       {
         query,
-        instrumentKind: 'INSTRUMENT_TYPE_BOND',
+        instrumentKind: TbankInstrumentType.Bond,
       },
     ).then((response) => response.instruments ?? []);
   }
@@ -337,7 +345,7 @@ export class TbankClient {
       this.sparseInstruments,
       'bondBy',
       {
-        idType: 'INSTRUMENT_ID_TYPE_UID',
+        idType: InstrumentIdType.Uid,
         id: uid,
       },
     ).then((response) => response.instrument ?? null);
@@ -367,7 +375,7 @@ export class TbankClient {
       this.instruments,
       'shareBy',
       {
-        idType: 'INSTRUMENT_ID_TYPE_UID',
+        idType: InstrumentIdType.Uid,
         id: uid,
       },
     ).then((response) => response.instrument ?? null);
@@ -446,7 +454,7 @@ export class TbankClient {
         to: {
           seconds: String(Math.floor(to.valueOf() / MILLISECONDS_PER_SECOND)),
         },
-        interval: 'CANDLE_INTERVAL_DAY',
+        interval: TbankCandleInterval.Day,
         limit: 2400,
       },
     ).then((response) => response.candles ?? []);
@@ -454,7 +462,7 @@ export class TbankClient {
 
   private async getInstrument(
     token: string,
-    idType: 'INSTRUMENT_ID_TYPE_FIGI' | 'INSTRUMENT_ID_TYPE_UID',
+    idType: InstrumentIdType,
     id: string,
   ): Promise<null | TbankInstrument> {
     try {
@@ -484,7 +492,7 @@ export class TbankClient {
       const queueFull = this.queue.size >= MAX_QUEUE_SIZE;
       try {
         if (queueFull) {
-          throw new ServiceUnavailableException({ code: 'TBANK_UNAVAILABLE' });
+          throw new ServiceUnavailableException({ code: TbankErrorCode.Unavailable });
         }
         const response = await this.queue.run(() =>
           this.request<Response>(token, client, method, request),
@@ -498,7 +506,7 @@ export class TbankClient {
       } catch (error) {
         const grpcCode = (error as ServiceError).code;
         const failureContext = queueFull
-          ? { code: 'TBANK_UNAVAILABLE' }
+          ? { code: TbankErrorCode.Unavailable }
           : { grpcCode };
         const retryable = queueFull
           ? metadataCall
@@ -534,7 +542,7 @@ export class TbankClient {
           [status.PERMISSION_DENIED, status.UNAUTHENTICATED].includes(grpcCode)
         ) {
           // eslint-disable-next-line preserve-caught-error -- Discard raw upstream authentication errors at the integration boundary.
-          throw new Error('INVALID_TBANK_TOKEN');
+          throw new Error(TbankErrorCode.InvalidToken);
         }
         if (
           grpcCode === status.NOT_FOUND &&
@@ -542,10 +550,10 @@ export class TbankClient {
         ) {
           throw new NotFoundException();
         }
-        throw new ServiceUnavailableException({ code: 'TBANK_UNAVAILABLE' });
+        throw new ServiceUnavailableException({ code: TbankErrorCode.Unavailable });
       }
     }
-    throw new ServiceUnavailableException({ code: 'TBANK_UNAVAILABLE' });
+    throw new ServiceUnavailableException({ code: TbankErrorCode.Unavailable });
   }
 
   private request<Response>(

src/modules/auth/application/auth-error-code.ts

@@ -0,0 +1,4 @@
+export enum AuthErrorCode {
+  EmailAlreadyRegistered = 'EMAIL_ALREADY_REGISTERED',
+  InvalidCredentials = 'INVALID_CREDENTIALS',
+}

src/modules/auth/application/auth.service.ts

@@ -8,7 +8,10 @@ import * as bcrypt from 'bcrypt';
 import { createHash, randomUUID } from 'crypto';
 
 import { Session, User } from '../../../../generated/prisma/client';
+import { HttpErrorCode } from '../../../common/error-code';
+import { isPrismaErrorCode, PrismaErrorCode } from '../../../prisma/prisma-error-code';
 import { PrismaService } from '../../../prisma/prisma.service';
+import { AuthErrorCode } from './auth-error-code';
 import { AuthUser, RefreshPayload } from './auth.types';
 
 const EXPECTED_ROTATED_SESSIONS = 1;
@@ -37,7 +40,7 @@ export class AuthService {
       where: { email },
     });
     if (existing) {
-      throw new ConflictException({ code: 'EMAIL_ALREADY_REGISTERED' });
+      throw new ConflictException({ code: AuthErrorCode.EmailAlreadyRegistered });
     }
 
     let user: User;
@@ -51,7 +54,7 @@ export class AuthService {
       });
     } catch (error) {
       if (isUniqueConstraintError(error)) {
-        throw new ConflictException({ code: 'EMAIL_ALREADY_REGISTERED' });
+        throw new ConflictException({ code: AuthErrorCode.EmailAlreadyRegistered });
       }
       throw error;
     }
@@ -70,7 +73,7 @@ export class AuthService {
       user?.passwordHash ?? DUMMY_PASSWORD_HASH,
     );
     if (!user || !valid) {
-      throw new UnauthorizedException({ code: 'INVALID_CREDENTIALS' });
+      throw new UnauthorizedException({ code: AuthErrorCode.InvalidCredentials });
     }
     return this.createSession(user);
   }
@@ -84,10 +87,10 @@ export class AuthService {
         algorithms: ['HS256'],
       });
     } catch {
-      throw new UnauthorizedException({ code: 'UNAUTHORIZED' });
+      throw new UnauthorizedException({ code: HttpErrorCode.Unauthorized });
     }
     if (payload.type !== 'refresh') {
-      throw new UnauthorizedException({ code: 'UNAUTHORIZED' });
+      throw new UnauthorizedException({ code: HttpErrorCode.Unauthorized });
     }
     const session = await this.prisma.session.findUnique({
       where: { id: payload.sid },
@@ -102,10 +105,10 @@ export class AuthService {
       if (session && !session.revokedAt) {
         await this.prisma.session.delete({ where: { id: session.id } });
       }
-      throw new UnauthorizedException({ code: 'UNAUTHORIZED' });
+      throw new UnauthorizedException({ code: HttpErrorCode.Unauthorized });
     }
     if (session.refreshTokenHash !== this.hash(token)) {
-      throw new UnauthorizedException({ code: 'UNAUTHORIZED' });
+      throw new UnauthorizedException({ code: HttpErrorCode.Unauthorized });
     }
     return this.rotateSession(session, session.refreshTokenHash);
   }
@@ -142,7 +145,7 @@ export class AuthService {
 
   async userById(id: string): Promise<User> {
     const user = await this.prisma.user.findUnique({ where: { id } });
-    if (!user) throw new UnauthorizedException({ code: 'UNAUTHORIZED' });
+    if (!user) throw new UnauthorizedException({ code: HttpErrorCode.Unauthorized });
     return user;
   }
 
@@ -183,7 +186,7 @@ export class AuthService {
         data,
       });
       if (updated.count !== EXPECTED_ROTATED_SESSIONS) {
-        throw new UnauthorizedException({ code: 'UNAUTHORIZED' });
+        throw new UnauthorizedException({ code: HttpErrorCode.Unauthorized });
       }
     } else {
       await this.prisma.session.update({ where: { id: session.id }, data });
@@ -208,6 +211,6 @@ function isUniqueConstraintError(error: unknown): boolean {
     typeof error === 'object' &&
     error !== null &&
     'code' in error &&
-    (error as { code?: unknown }).code === 'P2002'
+    isPrismaErrorCode(error.code, PrismaErrorCode.UniqueConstraint)
   );
 }

src/modules/auth/infrastructure/jwt.strategy.ts

@@ -3,6 +3,7 @@ import { ConfigService } from '@nestjs/config';
 import { PassportStrategy } from '@nestjs/passport';
 import { ExtractJwt, Strategy } from 'passport-jwt';
 
+import { HttpErrorCode } from '../../../common/error-code';
 import { Environment } from '../../../config/env.validation';
 import { AccessPayload } from '../application/auth.types';
 
@@ -19,7 +20,7 @@ export class JwtStrategy extends PassportStrategy(Strategy) {
 
   validate(payload: AccessPayload): AccessPayload {
     if (payload.type !== 'access') {
-      throw new UnauthorizedException({ code: 'UNAUTHORIZED' });
+      throw new UnauthorizedException({ code: HttpErrorCode.Unauthorized });
     }
     return payload;
   }

src/modules/auth/presentation/auth.controller.ts

@@ -21,6 +21,7 @@ import {
 } from '@nestjs/swagger';
 
 import { ApiProblemResponses } from '../../../common/decorators/api-safe-error-response.decorator';
+import { HttpErrorCode } from '../../../common/error-code';
 import { AuthService } from '../application/auth.service';
 import { AccessPayload } from '../application/auth.types';
 import { CredentialsDto } from './auth.dto';
@@ -86,7 +87,7 @@ export class AuthController {
   ) {
     try {
       const token = this.refreshToken(request);
-      if (!token) throw new UnauthorizedException({ code: 'UNAUTHORIZED' });
+      if (!token) throw new UnauthorizedException({ code: HttpErrorCode.Unauthorized });
       return this.respond(response, await this.auth.refresh(token));
     } catch (error) {
       if (error instanceof UnauthorizedException) this.clearCookie(response);

src/modules/banking/bank-cards/application/bank-card-input.ts

@@ -22,24 +22,23 @@ import {
 const NEXT_MONTH_OFFSET = 1;
 const PREVIOUS_MONTH_LAST_DAY = 0;
 
-export const BankErrorCode = {
-  InvalidInput: 'BANK_INVALID_INPUT',
-  VersionConflict: 'BANK_VERSION_CONFLICT',
-  NotFound: 'BANK_NOT_FOUND',
-  InvalidMoney: 'BANK_INVALID_MONEY',
-  InvalidDate: 'BANK_INVALID_DATE',
-  ImmutableOperation: 'BANK_IMMUTABLE_OPERATION',
-  InvalidRefund: 'BANK_INVALID_REFUND',
-  RefundLimit: 'BANK_REFUND_LIMIT',
-  DependentRefunds: 'BANK_DEPENDENT_REFUNDS',
-  IntentConflict: 'BANK_INTENT_CONFLICT',
-  OperationDeleted: 'BANK_OPERATION_DELETED',
-  CardArchived: 'BANK_CARD_ARCHIVED',
-  OpeningDateConflict: 'BANK_OPENING_DATE_CONFLICT',
-  WriteConflict: 'BANK_WRITE_CONFLICT',
-  DuplicateCategory: 'BANK_DUPLICATE_CATEGORY',
-} as const;
-export type BankErrorCode = (typeof BankErrorCode)[keyof typeof BankErrorCode];
+export enum BankErrorCode {
+  CardArchived = 'BANK_CARD_ARCHIVED',
+  DependentRefunds = 'BANK_DEPENDENT_REFUNDS',
+  DuplicateCategory = 'BANK_DUPLICATE_CATEGORY',
+  ImmutableOperation = 'BANK_IMMUTABLE_OPERATION',
+  IntentConflict = 'BANK_INTENT_CONFLICT',
+  InvalidDate = 'BANK_INVALID_DATE',
+  InvalidInput = 'BANK_INVALID_INPUT',
+  InvalidMoney = 'BANK_INVALID_MONEY',
+  InvalidRefund = 'BANK_INVALID_REFUND',
+  NotFound = 'BANK_NOT_FOUND',
+  OpeningDateConflict = 'BANK_OPENING_DATE_CONFLICT',
+  OperationDeleted = 'BANK_OPERATION_DELETED',
+  RefundLimit = 'BANK_REFUND_LIMIT',
+  VersionConflict = 'BANK_VERSION_CONFLICT',
+  WriteConflict = 'BANK_WRITE_CONFLICT',
+}
 
 export function fail(code: BankErrorCode = BankErrorCode.InvalidInput): never {
   throw new BadRequestException({ code });

src/modules/banking/bank-cards/infrastructure/bank-cards.repository.ts

@@ -2,6 +2,7 @@ import { Injectable } from '@nestjs/common';
 import { randomUUID } from 'node:crypto';
 
 import { Prisma } from '../../../../../generated/prisma/client';
+import { isPrismaErrorCode, PrismaErrorCode } from '../../../../prisma/prisma-error-code';
 import { PrismaService } from '../../../../prisma/prisma.service';
 import {
   BankErrorCode,
@@ -44,15 +45,15 @@ export class BankCardsRepository {
             ? error.code
             : '';
         const busy =
-          code === 'P2034' ||
-          code === 'P2028' ||
+          isPrismaErrorCode(code, PrismaErrorCode.WriteConflict) ||
+          isPrismaErrorCode(code, PrismaErrorCode.TransactionFailure) ||
           (error instanceof Error &&
             /SQLITE_BUSY|database is locked/.test(error.message));
-        if ((busy || code === 'P2002') && attempt < MAX_WRITE_RETRY_COUNT) {
+        if ((busy || isPrismaErrorCode(code, PrismaErrorCode.UniqueConstraint)) && attempt < MAX_WRITE_RETRY_COUNT) {
           continue;
         }
         if (busy) conflict(BankErrorCode.WriteConflict);
-        if (code === 'P2002') conflict(BankErrorCode.DuplicateCategory);
+        if (isPrismaErrorCode(code, PrismaErrorCode.UniqueConstraint)) conflict(BankErrorCode.DuplicateCategory);
         throw error;
       }
     }

src/modules/investments/income/income-analytics.service.ts

@@ -8,6 +8,7 @@ import {
   formatDecimal,
   subtract,
 } from '../../../common/decimal';
+import { isTbankProtocolValue, TbankOperationType } from '../../../integrations/tbank/tbank-protocol';
 import { DateOnlyRange, moscowDate } from '../investment-calendar';
 import { investmentResourceMeta } from '../investment-resource.mapper';
 import {
@@ -165,7 +166,7 @@ function qualifying(entries: BrokerageOperationDto[]): BrokerageOperationDto[] {
   return entries.filter(
     (entry) =>
       Boolean(entry.payment) &&
-      ['OPERATION_TYPE_COUPON', 'OPERATION_TYPE_DIVIDEND'].includes(entry.type),
+      [TbankOperationType.Coupon, TbankOperationType.Dividend].some((type) => isTbankProtocolValue(entry.type, type)),
   );
 }
 
@@ -184,7 +185,7 @@ function totals(entries: BrokerageOperationDto[]): IncomeCurrencySummaryDto[] {
     if (!entry.payment) continue;
     const total = values.get(entry.payment.currency) ?? zeroTotal();
     const value = decimalFromString(entry.payment.value);
-    if (entry.type === 'OPERATION_TYPE_COUPON') {
+    if (isTbankProtocolValue(entry.type, TbankOperationType.Coupon)) {
       total.coupon = add(total.coupon, value);
     } else total.dividend = add(total.dividend, value);
     values.set(entry.payment.currency, total);

src/modules/investments/income/income-period.ts

@@ -8,6 +8,8 @@ import {
   utcDate,
 } from '../investment-calendar';
 
+enum IncomeErrorCode { InvalidPeriod = 'INVALID_INCOME_PERIOD' }
+
 const MONDAY_WEEKDAY_INDEX = 1;
 const INCLUSIVE_DAY_OFFSET = 1;
 const NEXT_DAY_OFFSET = 1;
@@ -163,5 +165,5 @@ function yearAgo(range: DateOnlyRange): DateOnlyRange | null {
 }
 
 function invalidPeriod(): BadRequestException {
-  return new BadRequestException({ code: 'INVALID_INCOME_PERIOD' });
+  return new BadRequestException({ code: IncomeErrorCode.InvalidPeriod });
 }

src/modules/investments/instruments/application/candle.service.ts

@@ -9,6 +9,7 @@ import { formatDecimal } from '../../../../common/decimal';
 import { StructuredLogger } from '../../../../common/logging/structured-logger.service';
 import { MILLISECONDS_PER_DAY } from '../../../../common/time';
 import { decimal } from '../../../../integrations/tbank/decimal';
+import { isTbankErrorCode, TbankErrorCode } from '../../../../integrations/tbank/tbank-error-code';
 import {
   TbankAccessService,
   TbankClient,
@@ -23,6 +24,7 @@ import {
   candleWindows,
   utcDay,
 } from '../domain/candle-coverage';
+import { InstrumentErrorCode } from '../domain/instrument-error-code';
 import { CandleRepository } from '../infrastructure/candle.repository';
 import { CatalogEnrichmentService } from './catalog-enrichment.service';
 import { timestamp } from './instrument-market';
@@ -71,8 +73,8 @@ function rangeFor(
       throw new ServiceUnavailableException({
         code:
           input.instrumentType === 'share'
-            ? 'STOCK_HISTORY_START_UNAVAILABLE'
-            : 'BOND_HISTORY_START_UNAVAILABLE',
+            ? InstrumentErrorCode.StockHistoryStartUnavailable
+            : InstrumentErrorCode.BondHistoryStartUnavailable,
       });
     }
     from.setTime(utcDay(new Date(history)).valueOf());
@@ -448,7 +450,7 @@ export class CandleService {
         const producer = this.queue.shift();
         if (!producer) break;
         let success = false;
-        let code = 'TBANK_UNAVAILABLE';
+        let code: string = TbankErrorCode.Unavailable;
         try {
           const result = await this.load(producer);
           if (result === null) {
@@ -457,7 +459,7 @@ export class CandleService {
           }
           success = result;
         } catch (error) {
-          if (error instanceof Error && error.message === 'INVALID_TBANK_TOKEN') {
+          if (error instanceof Error && isTbankErrorCode(error.message, TbankErrorCode.InvalidToken)) {
             await this.access.rejectMembershipToken(producer.attempt);
           }
           if (error instanceof ServiceUnavailableException) {
@@ -523,7 +525,7 @@ export class CandleService {
       }
     } catch {
       this.logger.event('error', 'candles.persistence-failed', {
-        code: 'TBANK_UNAVAILABLE',
+        code: TbankErrorCode.Unavailable,
       });
     } finally {
       this.active.clear();

src/modules/investments/instruments/application/catalog-discovery.service.ts

@@ -6,6 +6,7 @@ import {
 import { randomUUID } from 'node:crypto';
 
 import { StructuredLogger } from '../../../../common/logging/structured-logger.service';
+import { isTbankErrorCode, TbankErrorCode } from '../../../../integrations/tbank/tbank-error-code';
 import {
   TbankAccessService,
   TbankClient,
@@ -14,6 +15,7 @@ import {
   type TbankSyncAttempt,
 } from '../../../../integrations/tbank/tbank.api';
 import { investmentResourceMeta } from '../../investment-resource.mapper';
+import { InstrumentErrorCode } from '../domain/instrument-error-code';
 import {
   CatalogDiscoveryRepository,
   catalogQuery,
@@ -209,8 +211,8 @@ export class CatalogDiscoveryService {
       throw new ConflictException({
         code:
           instrumentType === 'share'
-            ? 'STOCK_TICKER_AMBIGUOUS'
-            : 'BOND_TICKER_AMBIGUOUS',
+            ? InstrumentErrorCode.StockTickerAmbiguous
+            : InstrumentErrorCode.BondTickerAmbiguous,
       });
     }
     const result = lookup.data
@@ -357,11 +359,11 @@ export class CatalogDiscoveryService {
             );
           }
         } catch (error) {
-          if (error instanceof Error && error.message === 'INVALID_TBANK_TOKEN') {
+          if (error instanceof Error && isTbankErrorCode(error.message, TbankErrorCode.InvalidToken)) {
             await this.access.rejectMembershipToken(attempt);
           } else {
             this.logger.event('warn', 'catalog-discovery.failed', {
-              code: 'TBANK_UNAVAILABLE',
+              code: TbankErrorCode.Unavailable,
             });
           }
         }
@@ -395,7 +397,7 @@ export class CatalogDiscoveryService {
       this.producers.clear();
       this.queue.length = 0;
       this.logger.event('error', 'catalog-discovery.persistence-failed', {
-        code: 'TBANK_UNAVAILABLE',
+        code: TbankErrorCode.Unavailable,
       });
     } finally {
       this.running = false;

src/modules/investments/instruments/application/catalog-enrichment.service.ts

@@ -14,6 +14,7 @@ import {
 import { type MoexBondEvent, MoexClient } from '../../../../integrations/moex/moex.api';
 import { NcrRatingsClient } from '../../../../integrations/ncr/ncr.api';
 import { decimal } from '../../../../integrations/tbank/decimal';
+import { isTbankErrorCode, TbankErrorCode } from '../../../../integrations/tbank/tbank-error-code';
 import {
   TbankAccessService,
   type TbankBond,
@@ -520,11 +521,11 @@ export class CatalogEnrichmentService {
           }
         } catch (error) {
           failed = true;
-          if (error instanceof Error && error.message === 'INVALID_TBANK_TOKEN') {
+          if (error instanceof Error && isTbankErrorCode(error.message, TbankErrorCode.InvalidToken)) {
             await this.access.rejectMembershipToken(producer.attempt);
           } else {
             this.logger.event('warn', 'catalog-enrichment.failed', {
-              code: 'TBANK_UNAVAILABLE',
+              code: TbankErrorCode.Unavailable,
             });
           }
         }
@@ -572,7 +573,7 @@ export class CatalogEnrichmentService {
       this.producers.clear();
       this.queue.length = 0;
       this.logger.event('error', 'catalog-enrichment.persistence-failed', {
-        code: 'TBANK_UNAVAILABLE',
+        code: TbankErrorCode.Unavailable,
       });
     } finally {
       this.running = false;

src/modules/investments/instruments/application/catalog-selection.ts

@@ -1,5 +1,7 @@
 import type { TbankShare } from '../../../../integrations/tbank/tbank.api';
 
+import { TbankInstrumentType } from '../../../../integrations/tbank/tbank-protocol';
+
 export const catalogSearchLimit = 30;
 
 export function selectCatalogInstruments<T extends TbankShare>(
@@ -10,8 +12,8 @@ export function selectCatalogInstruments<T extends TbankShare>(
   const seen = new Set<string>();
   const kind =
     instrumentType === 'share'
-      ? 'INSTRUMENT_TYPE_SHARE'
-      : 'INSTRUMENT_TYPE_BOND';
+      ? TbankInstrumentType.Share
+      : TbankInstrumentType.Bond;
   const preferredClass = instrumentType === 'share' ? 'TQBR' : 'TQOB';
   return found
     .filter(

src/modules/investments/instruments/bonds/application/bond-income.service.ts

@@ -7,6 +7,7 @@ import {
   multiply,
 } from '../../../../../common/decimal';
 import { ISO_DATE_LENGTH, ISO_DATE_START } from '../../../../../common/time';
+import { isTbankProtocolValue, TbankCouponType } from '../../../../../integrations/tbank/tbank-protocol';
 import {
   TbankAccessService,
   type TbankBond,
@@ -241,10 +242,10 @@ export function bondMetrics(
         )
       : null;
   const couponType =
-    next?.couponType && next.couponType !== 'COUPON_TYPE_UNSPECIFIED'
+    next?.couponType && !isTbankProtocolValue(next.couponType, TbankCouponType.Unspecified)
       ? next.couponType
       : instrument.floatingCouponFlag === true
-        ? 'COUPON_TYPE_FLOATING'
+        ? TbankCouponType.Floating
         : null;
   return {
     creditRating,

src/modules/investments/instruments/domain/instrument-error-code.ts

@@ -0,0 +1,6 @@
+export enum InstrumentErrorCode {
+  BondHistoryStartUnavailable = 'BOND_HISTORY_START_UNAVAILABLE',
+  BondTickerAmbiguous = 'BOND_TICKER_AMBIGUOUS',
+  StockHistoryStartUnavailable = 'STOCK_HISTORY_START_UNAVAILABLE',
+  StockTickerAmbiguous = 'STOCK_TICKER_AMBIGUOUS',
+}

src/modules/investments/instruments/infrastructure/catalog-discovery.repository.ts

@@ -3,12 +3,9 @@ import { randomUUID } from 'node:crypto';
 import { isDeepStrictEqual } from 'node:util';
 
 import type { Prisma } from '../../../../../generated/prisma/client';
-import type {
-  TbankBond,
-  TbankShare,
-  TbankSyncAttempt,
-} from '../../../../integrations/tbank/tbank.api';
+import type { TbankBond, TbankShare, TbankSyncAttempt } from '../../../../integrations/tbank/tbank.api';
 
+import { TbankErrorCode } from '../../../../integrations/tbank/tbank-error-code';
 import { PrismaService } from '../../../../prisma/prisma.service';
 
 const UNCHANGED_REVISION_INCREMENT = 0;
@@ -462,7 +459,7 @@ export class CatalogDiscoveryRepository {
           state: 'running',
           connection: { invalidToken: true },
         },
-        data: { state: 'failed', errorCode: 'INVALID_TBANK_TOKEN' },
+        data: { state: 'failed', errorCode: TbankErrorCode.InvalidToken },
       });
       await tx.tbankSyncWork.updateMany({
         where: {
@@ -472,7 +469,7 @@ export class CatalogDiscoveryRepository {
         },
         data: {
           state: success ? 'complete' : 'failed',
-          errorCode: success ? null : 'TBANK_UNAVAILABLE',
+          errorCode: success ? null : TbankErrorCode.Unavailable,
         },
       });
     });

src/modules/investments/operations/application/brokerage-operations-sync.service.ts

@@ -3,10 +3,9 @@ import { randomUUID } from 'node:crypto';
 
 import { StructuredLogger } from '../../../../common/logging/structured-logger.service';
 import { MILLISECONDS_PER_SECOND } from '../../../../common/time';
-import {
-  TbankAccessService,
-  TbankClient,
-} from '../../../../integrations/tbank/tbank.api';
+import { isTbankErrorCode, TbankErrorCode } from '../../../../integrations/tbank/tbank-error-code';
+import { TbankOperationState } from '../../../../integrations/tbank/tbank-protocol';
+import { TbankAccessService, TbankClient } from '../../../../integrations/tbank/tbank.api';
 import { accountHistory } from '../../investment-sync-plan';
 import {
   type OperationInterval,
@@ -208,7 +207,7 @@ export class BrokerageOperationsSyncService {
           this.logger.event(
             'error',
             'tbank.operations.sync.persistence_failed',
-            { userId: attempt.userId, code: 'TBANK_UNAVAILABLE' },
+            { userId: attempt.userId, code: TbankErrorCode.Unavailable },
           );
         }
         const next = pending ? await this.repository.pending(attempt) : null;
@@ -272,7 +271,7 @@ export class BrokerageOperationsSyncService {
           : {}),
         cursor,
         limit: operationsPageSize,
-        state: 'OPERATION_STATE_EXECUTED',
+        state: TbankOperationState.Executed,
       });
       if (
         !(await this.repository.stagePage(attempt, interval, cursor, response))
@@ -297,7 +296,7 @@ export class BrokerageOperationsSyncService {
     } catch (error) {
       await this.repository.fail(
         attempt,
-        error instanceof Error && error.message === 'INVALID_TBANK_TOKEN',
+        error instanceof Error && isTbankErrorCode(error.message, TbankErrorCode.InvalidToken),
       );
       return false;
     }

src/modules/investments/operations/application/brokerage-operations.service.ts

@@ -17,6 +17,7 @@ import {
   ledgerRange,
   planInvestmentScreen,
 } from '../../investment-sync-plan';
+import { OperationErrorCode } from '../domain/operation-error-code';
 import {
   operationIntervalsOverlap,
   operationsSyncPriority,
@@ -442,7 +443,7 @@ export class BrokerageOperationsService {
       }
       return cursor as LocalOperationsCursor;
     } catch {
-      throw new BadRequestException({ code: 'INVALID_OPERATIONS_CURSOR' });
+      throw new BadRequestException({ code: OperationErrorCode.InvalidOperationsCursor });
     }
   }
 

src/modules/investments/operations/domain/operation-error-code.ts

@@ -0,0 +1,3 @@
+export enum OperationErrorCode {
+  InvalidOperationsCursor = 'INVALID_OPERATIONS_CURSOR',
+}

src/modules/investments/operations/infrastructure/brokerage-operation.mapper.ts

@@ -1,10 +1,8 @@
 import { formatDecimal } from '../../../../common/decimal';
 import { MILLISECONDS_PER_SECOND } from '../../../../common/time';
 import { decimal } from '../../../../integrations/tbank/decimal';
-import {
-  TbankMoney,
-  TbankOperationItem,
-} from '../../../../integrations/tbank/tbank.api';
+import { TbankOperationType } from '../../../../integrations/tbank/tbank-protocol';
+import { TbankMoney, TbankOperationItem } from '../../../../integrations/tbank/tbank.api';
 import {
   BrokerageOperationDto,
   OperationCategory,
@@ -15,29 +13,29 @@ const MISSING_TIMESTAMP_COMPONENT = 0;
 const NANOSECONDS_PER_MILLISECOND = 1_000_000;
 
 const types: Record<string, OperationCategory> = {
-  OPERATION_TYPE_BUY: 'trade',
-  OPERATION_TYPE_BUY_CARD: 'trade',
-  OPERATION_TYPE_SELL: 'trade',
-  OPERATION_TYPE_SELL_CARD: 'trade',
-  OPERATION_TYPE_BUY_MARGIN: 'trade',
-  OPERATION_TYPE_SELL_MARGIN: 'trade',
-  OPERATION_TYPE_COUPON: 'income',
-  OPERATION_TYPE_DIVIDEND: 'income',
-  OPERATION_TYPE_DIVIDEND_TRANSFER: 'income',
-  OPERATION_TYPE_DIV_EXT: 'income',
-  OPERATION_TYPE_TRANS_IIS_BS: 'transfer',
-  OPERATION_TYPE_TRANS_BS_BS: 'transfer',
-  OPERATION_TYPE_BOND_TAX: 'tax',
-  OPERATION_TYPE_TAX: 'tax',
-  OPERATION_TYPE_DIVIDEND_TAX: 'tax',
-  OPERATION_TYPE_SERVICE_FEE: 'fee',
-  OPERATION_TYPE_MARGIN_FEE: 'fee',
-  OPERATION_TYPE_BROKER_FEE: 'fee',
-  OPERATION_TYPE_SUCCESS_FEE: 'fee',
-  OPERATION_TYPE_INPUT: 'transfer',
-  OPERATION_TYPE_OUTPUT: 'transfer',
-  OPERATION_TYPE_INPUT_SECURITIES: 'transfer',
-  OPERATION_TYPE_OUTPUT_SECURITIES: 'transfer',
+  [TbankOperationType.Buy]: 'trade',
+  [TbankOperationType.BuyCard]: 'trade',
+  [TbankOperationType.Sell]: 'trade',
+  [TbankOperationType.SellCard]: 'trade',
+  [TbankOperationType.BuyMargin]: 'trade',
+  [TbankOperationType.SellMargin]: 'trade',
+  [TbankOperationType.Coupon]: 'income',
+  [TbankOperationType.Dividend]: 'income',
+  [TbankOperationType.DividendTransfer]: 'income',
+  [TbankOperationType.DivExt]: 'income',
+  [TbankOperationType.TransIisBs]: 'transfer',
+  [TbankOperationType.TransBsBs]: 'transfer',
+  [TbankOperationType.BondTax]: 'tax',
+  [TbankOperationType.Tax]: 'tax',
+  [TbankOperationType.DividendTax]: 'tax',
+  [TbankOperationType.ServiceFee]: 'fee',
+  [TbankOperationType.MarginFee]: 'fee',
+  [TbankOperationType.BrokerFee]: 'fee',
+  [TbankOperationType.SuccessFee]: 'fee',
+  [TbankOperationType.Input]: 'transfer',
+  [TbankOperationType.Output]: 'transfer',
+  [TbankOperationType.InputSecurities]: 'transfer',
+  [TbankOperationType.OutputSecurities]: 'transfer',
 };
 
 export function operationCategory(type: string | undefined): OperationCategory {
@@ -51,7 +49,7 @@ export function mapBrokerageOperation(
   return {
     id: operation.id ?? operation.cursor ?? '',
     occurredAt: occurredAt.toISOString(),
-    type: operation.type ?? 'OPERATION_TYPE_UNSPECIFIED',
+    type: operation.type ?? TbankOperationType.Unspecified,
     category: operationCategory(operation.type),
     description: operation.description?.trim() || operation.name?.trim() || '',
     figi: text(operation.figi),

src/modules/investments/operations/infrastructure/brokerage-operations.repository.ts

@@ -12,12 +12,15 @@ import type {
   TbankOperationsByCursorResponse,
 } from '../../../../integrations/tbank/tbank.api';
 
+import { TbankErrorCode } from '../../../../integrations/tbank/tbank-error-code';
+import { isTbankProtocolValue, TbankOperationState } from '../../../../integrations/tbank/tbank-protocol';
 import { PrismaService } from '../../../../prisma/prisma.service';
 import {
   dateOnlyBounds,
   DateOnlyRange,
   moscowDate,
 } from '../../investment-calendar';
+import { OperationErrorCode } from '../domain/operation-error-code';
 import {
   type OperationInterval,
   operationIntervals,
@@ -137,7 +140,7 @@ export class BrokerageOperationsRepository {
         )
         .digest('base64url');
       if (input.cursor && input.cursor.binding !== binding) {
-        throw new BadRequestException({ code: 'INVALID_OPERATIONS_CURSOR' });
+        throw new BadRequestException({ code: OperationErrorCode.InvalidOperationsCursor });
       }
       const scope = {
         userId: input.userId,
@@ -615,7 +618,7 @@ export class BrokerageOperationsRepository {
         where: { id: attempt.id },
         data: {
           state: 'failed',
-          errorCode: invalidToken ? 'INVALID_TBANK_TOKEN' : 'TBANK_UNAVAILABLE',
+          errorCode: invalidToken ? TbankErrorCode.InvalidToken : TbankErrorCode.Unavailable,
         },
       });
       if (invalidToken) {
@@ -784,7 +787,7 @@ export class BrokerageOperationsRepository {
           }
           const rows = staged.filter((row) => {
             const state = (row.payload as TbankOperationItem).state;
-            return !state || state === 'OPERATION_STATE_EXECUTED';
+            return !state || isTbankProtocolValue(state, TbankOperationState.Executed);
           });
           const scope = {
             userId: attempt.userId,

src/modules/investments/portfolio/application/portfolio.service.ts

@@ -17,6 +17,7 @@ import { RequestContextService } from '../../../../common/logging/request-contex
 import { StructuredLogger } from '../../../../common/logging/structured-logger.service';
 import { MoneyDto } from '../../../../common/money.dto';
 import { decimal } from '../../../../integrations/tbank/decimal';
+import { isTbankErrorCode, TbankErrorCode } from '../../../../integrations/tbank/tbank-error-code';
 import {
   InstrumentMetadataService,
   type MetadataIdentity,
@@ -387,7 +388,7 @@ export class PortfolioService {
           } catch (error) {
             if (
               error instanceof Error &&
-              error.message === 'INVALID_TBANK_TOKEN'
+              isTbankErrorCode(error.message, TbankErrorCode.InvalidToken)
             ) {
               await this.access.rejectMembershipToken(attempt);
             } else await this.repository.fail(attempt);
@@ -412,7 +413,7 @@ export class PortfolioService {
   async get(userId: string, accountId: string): Promise<PortfolioDto> {
     const result = await this.read(userId, accountId);
     if (!result.data) {
-      throw new ServiceUnavailableException({ code: 'TBANK_UNAVAILABLE' });
+      throw new ServiceUnavailableException({ code: TbankErrorCode.Unavailable });
     }
     return result.data;
   }

src/modules/investments/portfolio/infrastructure/portfolio.repository.ts

@@ -4,10 +4,8 @@ import { randomUUID } from 'node:crypto';
 import type { Prisma } from '../../../../../generated/prisma/client';
 import type { PortfolioDto } from '../presentation/portfolio.dto';
 
-import {
-  tbankSourceNeedsRefresh,
-  tbankSourceTtlMs,
-} from '../../../../integrations/tbank/tbank.api';
+import { TbankErrorCode } from '../../../../integrations/tbank/tbank-error-code';
+import { tbankSourceNeedsRefresh, tbankSourceTtlMs } from '../../../../integrations/tbank/tbank.api';
 import { PrismaService } from '../../../../prisma/prisma.service';
 
 const EXPECTED_UPDATED_ACCOUNTS = 1;
@@ -152,7 +150,7 @@ export class PortfolioRepository {
         state: 'running',
         connection: { invalidToken: false },
       },
-      data: { state: 'failed', errorCode: 'TBANK_UNAVAILABLE' },
+      data: { state: 'failed', errorCode: TbankErrorCode.Unavailable },
     });
     return result.count === EXPECTED_UPDATED_ACCOUNTS;
   }

src/modules/investments/tbank-connection/tbank-connection.service.ts

@@ -1,5 +1,6 @@
 import { BadRequestException, Inject, Injectable } from '@nestjs/common';
 
+import { HttpErrorCode } from '../../../common/error-code';
 import {
   supportedTbankAccounts,
   TbankClient,
@@ -29,7 +30,7 @@ export class TbankConnectionService {
 
   async put(userId: string, value: string) {
     const token = value.trim();
-    if (!token) throw new BadRequestException({ code: 'VALIDATION_ERROR' });
+    if (!token) throw new BadRequestException({ code: HttpErrorCode.ValidationError });
     const accounts = await this.tokens.translateInvalidToken(() =>
       this.tbank.validateToken(token),
     );

src/modules/investments/tbank-sync/tbank-sync.service.ts

@@ -9,6 +9,7 @@ import { randomUUID } from 'node:crypto';
 import type { InvestmentResourceMetaDto } from '../investment-resource.dto';
 
 import { ISO_DATE_LENGTH, ISO_DATE_START } from '../../../common/time';
+import { TbankErrorCode } from '../../../integrations/tbank/tbank-error-code';
 import {
   InstrumentMetadataService,
   TbankAccessService,
@@ -325,7 +326,7 @@ export class TbankSyncService {
       await this.repository.progress(attempt, children, true);
     } catch {
       await this.repository
-        .progress(attempt, children, true, 'TBANK_UNAVAILABLE')
+        .progress(attempt, children, true, TbankErrorCode.Unavailable)
         .catch(() => undefined);
     }
   }

src/modules/investments/upcoming-events/upcoming-events.service.ts

@@ -31,6 +31,8 @@ import {
   UpcomingEventsQueryDto,
 } from './upcoming-events.dto';
 
+enum EventsErrorCode { InvalidPeriod = 'INVALID_EVENTS_PERIOD' }
+
 const FIRST_BATCH_OFFSET = 0;
 
 const DEFAULT_EVENT_WINDOW_DAYS = 30;
@@ -267,7 +269,7 @@ function dateWindow(query: UpcomingEventsQueryDto) {
   end.setUTCDate(end.getUTCDate() + DEFAULT_EVENT_WINDOW_DAYS);
   const to = query.to ?? end.toISOString().slice(ISO_DATE_START, ISO_DATE_LENGTH);
   if (from > to) {
-    throw new BadRequestException({ code: 'INVALID_EVENTS_PERIOD' });
+    throw new BadRequestException({ code: EventsErrorCode.InvalidPeriod });
   }
   return { from, to };
 }

src/prisma/prisma-error-code.ts

@@ -0,0 +1,9 @@
+export enum PrismaErrorCode {
+  TransactionFailure = 'P2028',
+  UniqueConstraint = 'P2002',
+  WriteConflict = 'P2034',
+}
+
+export function isPrismaErrorCode(value: unknown, expected: PrismaErrorCode): boolean {
+  return value === expected;
+}

test/eslint-config.cjs

@@ -61,3 +61,27 @@ test('numeric literals require names, including previously ignored numbers and b
     assert.ok(!named.messages.some(({ ruleId }) => ruleId === '@typescript-eslint/no-magic-numbers'), literal);
   }
 });
+
+// Single-use codes must be caught too; fixture literals remain independent wire assertions.
+test('machine codes require enum members without banning ordinary text or Prisma selects', async () => {
+  const eslint = new ESLint();
+  const filePath = 'src/main.ts';
+  for (const code of ['export function check(code: string) { return code === "one-off-code"; }', 'export const result = `MOEX_UNAVAILABLE`;', 'export const result = { code: "one-off-code" };', 'export const result = { "errorCode": "one-off-code" };', 'export const result = { code: `dynamic-${Date.now()}` };', 'export const result = "MOEX_UNAVAILABLE";', 'export const result = ["INSTRUMENT_ID_TYPE_FIGI"];', 'export const result = { OPERATION_TYPE_COUPON: "income" };']) {
+    const [result] = await eslint.lintText(code, { filePath });
+    assert.equal(result.fatalErrorCount, 0, code);
+    assert.ok(result.messages.some(({ ruleId }) => ruleId === 'no-restricted-syntax'), code);
+  }
+  for (const code of [
+    'enum Code { Unavailable = "MOEX_UNAVAILABLE" } export const result = { code: Code.Unavailable };',
+    'export const select = { code: true, errorCode: true };',
+    'export const label = "Please try again"; export const key = "JWT_SECRET";',
+  ]) {
+    const [result] = await eslint.lintText(code, { filePath });
+    assert.equal(result.fatalErrorCount, 0, code);
+    assert.ok(!result.messages.some(({ ruleId }) => ruleId === 'no-restricted-syntax'), code);
+  }
+  const [fixture] = await eslint.lintText('export const result = { code: "MOEX_UNAVAILABLE" };', { filePath: 'src/integrations/moex/moex.client.spec.ts' });
+  assert.ok(!fixture.messages.some(({ ruleId }) => ruleId === 'no-restricted-syntax'));
+  const [comparison] = await eslint.lintText('enum Code { Ready = "ready" } export function check(code: Code) { return code === "ready"; }', { filePath });
+  assert.ok(comparison.messages.some(({ ruleId }) => ruleId === '@typescript-eslint/no-unsafe-enum-comparison'));
+});