feat(auth): authorization catalogues + Principal builder skeleton (ADR-0025)

Per ADR-0025's implementation phasing, lands the closed-set
catalogues + the OIDC-callback hook that composes the
session-resident Principal. No new guards yet.

- libs/shared/auth: framework-agnostic lib hosting
  authorization.types.ts (4 privileges + 24 functional roles + 6
  scope kinds + Principal type) and entra-group-to-role.ts
  (validated GUID -> slug resolver). 17 unit tests against the
  catalogues + resolver contracts.
- BFF: PrincipalBuilder composes the three axes once at sign-in;
  ScopeResolver seam (StubScopeResolver returns unrestricted in
  v1, replaced by a Prisma-backed implementation when ADR-0026's
  user_scopes table lands). 19 persona-driven tests covering the
  test tenant's full provisioning + edge cases (unknown
  privilege drift, unknown group GUID, empty permissions).
- AuthService extracts the Entra "groups" claim; AuthenticatedUser
  grows the groups: readonly string[] field.
- SessionEstablisher builds + persists the principal alongside
  the legacy user shape (additive — guards consuming user.oid
  unchanged).
- ENTRA_GROUP_MAP_PATH env var + load-entra-group-map.ts read
  the tenant-private map from infra/<env>-tenant.entra.json
  (gitignored; .example.json committed with the schema).
- ADR-0025 path references updated from libs/feature/auth
  (Angular-scoped, scope:portal-shell) to libs/shared/auth
  (consumable by both BFF and SPA).
- notes/entra-groups-claim-activation.md: operator runbook for
  the "Token configuration -> Add groups claim" step in the
  Entra admin centre.

Test plan:
- pnpm nx affected -t lint test build : 13 projects green
  (497 BFF tests + 17 shared-auth tests + 1 shared-util test +
  full lint + full build).

apps/portal-bff/.env.example

@@ -72,6 +72,18 @@ ENTRA_POST_LOGOUT_REDIRECT_URI=http://localhost:4200/
 ENTRA_ADMIN_REDIRECT_URI=http://localhost:3000/api/admin/auth/callback
 ENTRA_ADMIN_POST_LOGOUT_REDIRECT_URI=http://localhost:4300/
 
+# Authorization model (per ADR-0025). Points at the JSON file that
+# maps tenant-private Entra security-group GUIDs to the closed
+# catalogue of `apf-role-*` slugs. The BFF loads it at boot through
+# `EntraGroupToRoleResolver` (libs/shared/auth). Unset means the
+# resolver runs empty — sign-in still succeeds but every user gets
+# zero functional roles (no `apf-role-*` UI). A WARN is logged at
+# boot so an operator can spot the missing config. See
+# `infra/test-tenant.entra.example.json` for the schema; copy to
+# `infra/test-tenant.entra.json` (gitignored) and fill in the real
+# GUIDs from the Entra admin centre.
+ENTRA_GROUP_MAP_PATH=infra/test-tenant.entra.json
+
 # Cookie signing secret (per ADR-0009 §"Cookies"). Used to sign the
 # transient pre-auth cookie that carries the OIDC `state` + PKCE
 # verifier between the /auth/login redirect and the /auth/callback

apps/portal-bff/src/auth/auth.controller.spec.ts

@@ -150,11 +150,30 @@ function makeController(opts?: { completeAuthCodeFlow?: jest.Mock }): Controller
   // Real SessionEstablisher with the same mocks the legacy tests
   // already wire — keeps the behavioural assertions on session
   // fields / audit calls untouched after the controller refactor.
+  const principalBuilder = {
+    // The auth.controller specs do not assert on the principal
+    // shape; the resolved value just has to be a valid `Principal`
+    // so SessionEstablisher persists it without throwing.
+    build: jest.fn().mockResolvedValue({
+      user: {
+        id: 'oid',
+        personId: 'oid',
+        entraOid: 'oid',
+        tenantId: 'tid',
+        displayName: 'Jane',
+      },
+      privileges: [],
+      roles: [],
+      scopes: [{ kind: 'unrestricted' }],
+      amr: [],
+    }),
+  };
   const sessionEstablisher = new SessionEstablisher(
     logger as unknown as Logger,
     userSessionIndex as unknown as UserSessionIndexService,
     audit as unknown as AuditWriter,
     userDirectory as unknown as UserDirectoryService,
+    principalBuilder as unknown as import('./principal-builder').PrincipalBuilder,
   );
   return {
     controller: new AuthController(

apps/portal-bff/src/auth/auth.module.ts

@@ -2,12 +2,16 @@ import { ConfidentialClientApplication, LogLevel } from '@azure/msal-node';
 import { Module } from '@nestjs/common';
 import { Logger } from 'nestjs-pino';
 import { assertEntraConfig } from '../config/check-entra-config';
+import { loadEntraGroupToRoleResolver } from '../config/load-entra-group-map';
 import { SessionModule } from '../session/session.module';
 import { AuthController } from './auth.controller';
 import { AuthService } from './auth.service';
 import { ENTRA_CONFIG, type EntraConfig } from './entra-config.token';
+import { ENTRA_GROUP_TO_ROLE_RESOLVER } from './entra-group-to-role.token';
 import { MSAL_CLIENT } from './msal-client.token';
+import { PrincipalBuilder } from './principal-builder';
 import { RequireMfaGuard } from './require-mfa.guard';
+import { ScopeResolver, StubScopeResolver } from './scope-resolver';
 import { SessionEstablisher } from './session-establisher.service';
 
 /**
@@ -47,10 +51,35 @@ import { SessionEstablisher } from './session-establisher.service';
     AuthService,
     RequireMfaGuard,
     SessionEstablisher,
+    PrincipalBuilder,
+    { provide: ScopeResolver, useClass: StubScopeResolver },
     {
       provide: ENTRA_CONFIG,
       useFactory: () => assertEntraConfig(),
     },
+    {
+      provide: ENTRA_GROUP_TO_ROLE_RESOLVER,
+      inject: [Logger],
+      useFactory: (logger: Logger) => {
+        const { resolver, sourcePath } = loadEntraGroupToRoleResolver({
+          onWarn: (event, payload) => logger.warn({ event, ...payload }, 'AuthModule'),
+        });
+        // Log the post-load summary unconditionally so an operator
+        // grepping the boot log can confirm how many functional
+        // roles are wired without inspecting the JSON file. The
+        // file path (if any) helps diagnose env-var / cwd mismatches.
+        logger.log(
+          {
+            event: 'auth.entra_group_map_loaded',
+            sourcePath,
+            mappingCount: resolver.size,
+            coveredRoles: resolver.coveredRoles(),
+          },
+          'AuthModule',
+        );
+        return resolver;
+      },
+    },
     {
       provide: MSAL_CLIENT,
       inject: [ENTRA_CONFIG, Logger],
@@ -92,6 +121,15 @@ import { SessionEstablisher } from './session-establisher.service';
         }),
     },
   ],
-  exports: [ENTRA_CONFIG, MSAL_CLIENT, RequireMfaGuard, AuthService, SessionEstablisher],
+  exports: [
+    ENTRA_CONFIG,
+    ENTRA_GROUP_TO_ROLE_RESOLVER,
+    MSAL_CLIENT,
+    RequireMfaGuard,
+    AuthService,
+    PrincipalBuilder,
+    ScopeResolver,
+    SessionEstablisher,
+  ],
 })
 export class AuthModule {}

apps/portal-bff/src/auth/auth.service.spec.ts

@@ -38,6 +38,7 @@ function makeAuthResult(
   claims: Partial<{
     amr: string[];
     roles: unknown;
+    groups: unknown;
     oid: string;
     tid: string;
     name: string;
@@ -58,6 +59,12 @@ function makeAuthResult(
   if (Object.prototype.hasOwnProperty.call(claims, 'roles')) {
     idTokenClaims['roles'] = claims.roles;
   }
+  // Same opt-in pattern for `groups` — Entra emits it only when
+  // the app registration sets `groupMembershipClaims: 'SecurityGroup'`
+  // and the user is in at least one group.
+  if (Object.prototype.hasOwnProperty.call(claims, 'groups')) {
+    idTokenClaims['groups'] = claims.groups;
+  }
   return {
     idTokenClaims,
     account: { username: 'jane.doe@apf.example', name: 'Jane Doe' },
@@ -124,6 +131,7 @@ describe('AuthService.completeAuthCodeFlow', () => {
       displayName: 'Jane Doe',
       amr: ['pwd', 'mfa'],
       roles: [],
+      groups: [],
     });
   });
 
@@ -220,6 +228,80 @@ describe('AuthService.completeAuthCodeFlow', () => {
     expect(user.roles).toEqual(['admin', 'editor']);
   });
 
+  // `groups` claim — extracted identically to `roles`. The raw
+  // GUIDs are surfaced here; resolution to `apf-role-*` slugs
+  // happens downstream in `PrincipalBuilder` per ADR-0025.
+  it('surfaces the `groups` claim when Entra includes it (security-group member)', async () => {
+    const acquireTokenByCode = jest.fn().mockResolvedValue(
+      makeAuthResult({
+        groups: ['11111111-1111-1111-1111-111111111111', '22222222-2222-2222-2222-222222222222'],
+      }),
+    );
+    const { service } = makeService({ acquireTokenByCode });
+    const user = await service.completeAuthCodeFlow(
+      'code',
+      PRE_AUTH_OK.state,
+      PRE_AUTH_OK,
+      ENTRA.redirectUri,
+      PRE_AUTH_OK.createdAt,
+    );
+    expect(user.groups).toEqual([
+      '11111111-1111-1111-1111-111111111111',
+      '22222222-2222-2222-2222-222222222222',
+    ]);
+  });
+
+  it('returns an empty `groups` array when the claim is absent (no group membership)', async () => {
+    const acquireTokenByCode = jest.fn().mockResolvedValue(makeAuthResult({}));
+    const { service } = makeService({ acquireTokenByCode });
+    const user = await service.completeAuthCodeFlow(
+      'code',
+      PRE_AUTH_OK.state,
+      PRE_AUTH_OK,
+      ENTRA.redirectUri,
+      PRE_AUTH_OK.createdAt,
+    );
+    expect(user.groups).toEqual([]);
+  });
+
+  it('returns an empty `groups` array when the claim is non-array (defensive)', async () => {
+    const acquireTokenByCode = jest.fn().mockResolvedValue(makeAuthResult({ groups: 'oops' }));
+    const { service } = makeService({ acquireTokenByCode });
+    const user = await service.completeAuthCodeFlow(
+      'code',
+      PRE_AUTH_OK.state,
+      PRE_AUTH_OK,
+      ENTRA.redirectUri,
+      PRE_AUTH_OK.createdAt,
+    );
+    expect(user.groups).toEqual([]);
+  });
+
+  it('drops non-string entries from `groups` (defensive)', async () => {
+    const acquireTokenByCode = jest.fn().mockResolvedValue(
+      makeAuthResult({
+        groups: [
+          '11111111-1111-1111-1111-111111111111',
+          42,
+          null,
+          '22222222-2222-2222-2222-222222222222',
+        ],
+      }),
+    );
+    const { service } = makeService({ acquireTokenByCode });
+    const user = await service.completeAuthCodeFlow(
+      'code',
+      PRE_AUTH_OK.state,
+      PRE_AUTH_OK,
+      ENTRA.redirectUri,
+      PRE_AUTH_OK.createdAt,
+    );
+    expect(user.groups).toEqual([
+      '11111111-1111-1111-1111-111111111111',
+      '22222222-2222-2222-2222-222222222222',
+    ]);
+  });
+
   it('throws token-exchange-failed when MSAL throws', async () => {
     const acquireTokenByCode = jest.fn().mockRejectedValue(new Error('AADSTS70008'));
     const { service } = makeService({ acquireTokenByCode });

apps/portal-bff/src/auth/auth.service.ts

@@ -38,11 +38,23 @@ export interface AuthCodeFlowStart {
  *     the BFF's MFA sanity-check (ADR-0011) and by `@RequireMfa`
  *     freshness checks once the session lands.
  *   - `roles`: Entra app roles assigned to this user on the BFF's
- *     app registration. Surfaced for the future `@RequireAdmin` /
- *     `@RequireRole(...)` guards (ADR-0020 admin module). Always
- *     present in the shape — an empty array means the user has no
- *     app role on this app registration, not that the claim was
- *     unparseable.
+ *     app registration. These are the four `Portal.*` *privileges*
+ *     per ADR-0025 (`Portal.Admin`, `Portal.Auditor`,
+ *     `Portal.SecurityOfficer`, `Portal.DPO`). Surfaced for the
+ *     existing `@RequireAdmin()` guard and the upcoming
+ *     `@RequirePrivilege()` decorator. Always present in the shape
+ *     — an empty array means the user has no app role on this app
+ *     registration, not that the claim was unparseable.
+ *   - `groups`: Entra security-group GUIDs the user belongs to.
+ *     Emitted by the `groups` claim once the app registration sets
+ *     `groupMembershipClaims: 'SecurityGroup'` (per ADR-0025
+ *     §"Sources of truth — Entra-side configuration"). The
+ *     `PrincipalBuilder` resolves these GUIDs to `apf-role-*` slugs
+ *     via the `EntraGroupToRoleResolver`. Always present — empty
+ *     means either the user has no group membership or the claim
+ *     was not configured on the app registration. Unknown GUIDs
+ *     are dropped at resolve time, not at extraction time, so an
+ *     audit reader still sees the raw claim.
  */
 export interface AuthenticatedUser {
   readonly oid: string;
@@ -51,6 +63,7 @@ export interface AuthenticatedUser {
   readonly displayName: string;
   readonly amr: readonly string[];
   readonly roles: readonly string[];
+  readonly groups: readonly string[];
 }
 
 /**
@@ -212,6 +225,18 @@ export class AuthService {
       ? (claims['roles'] as unknown[]).filter((v): v is string => typeof v === 'string')
       : [];
 
+    // `groups` is an optional claim (per ADR-0025 §"Sources of truth
+    // — Entra-side configuration"). Present only when the app
+    // registration sets `groupMembershipClaims: 'SecurityGroup'`.
+    // Empty array if the user is in zero security groups or the
+    // claim is not configured — both are valid "no functional
+    // roles" states the rest of the BFF must tolerate. Same
+    // string-filter as `roles` to defend against a non-string value
+    // smuggled in via a malformed token.
+    const groups = Array.isArray(claims['groups'])
+      ? (claims['groups'] as unknown[]).filter((v): v is string => typeof v === 'string')
+      : [];
+
     return {
       oid: requireString(claims['oid'], 'oid'),
       tid: requireString(claims['tid'], 'tid'),
@@ -225,6 +250,7 @@ export class AuthService {
           : (result.account?.name ?? ''),
       amr,
       roles,
+      groups,
     };
   }
 }

apps/portal-bff/src/auth/entra-group-to-role.token.ts

@@ -0,0 +1,12 @@
+/**
+ * DI token for the lazily-loaded `EntraGroupToRoleResolver`.
+ *
+ * The resolver wraps a `Map<groupGuid, FunctionalRole>` parsed
+ * once at boot from `infra/<env>-tenant.entra.json` (per ADR-0025
+ * §"Sources of truth — Entra-side configuration"). The token is
+ * separate from the class import so the BFF can swap the
+ * implementation (an empty-map stub when no file is configured,
+ * a real one when `ENTRA_GROUP_MAP_PATH` resolves) without the
+ * consumers caring.
+ */
+export const ENTRA_GROUP_TO_ROLE_RESOLVER = Symbol('ENTRA_GROUP_TO_ROLE_RESOLVER');

apps/portal-bff/src/auth/principal-builder.spec.ts

@@ -0,0 +1,340 @@
+import type { Logger } from 'nestjs-pino';
+import {
+  EntraGroupToRoleResolver,
+  parseEntraGroupMap,
+  type FunctionalRole,
+  type Scope,
+} from 'shared-auth';
+import type { AuthenticatedUser } from './auth.service';
+import { PrincipalBuilder } from './principal-builder';
+import type { ScopeResolver } from './scope-resolver';
+
+/**
+ * Mirrors the 24-entry `apf-role-*` catalogue: one synthetic GUID
+ * per slug, in catalogue order. The exact GUIDs do not matter to
+ * any assertion below — what matters is that the test resolver
+ * maps them deterministically so a persona's `groups` claim can
+ * be assembled by slug.
+ */
+const ROLE_GUID: Record<FunctionalRole, string> = {
+  collaborateur: '00000000-0000-0000-0000-000000000101',
+  'chef-equipe': '00000000-0000-0000-0000-000000000102',
+  'chef-service': '00000000-0000-0000-0000-000000000103',
+  'directeur-etablissement': '00000000-0000-0000-0000-000000000104',
+  'directeur-territorial': '00000000-0000-0000-0000-000000000105',
+  rh: '00000000-0000-0000-0000-000000000106',
+  'responsable-paie': '00000000-0000-0000-0000-000000000107',
+  comptable: '00000000-0000-0000-0000-000000000108',
+  juriste: '00000000-0000-0000-0000-000000000109',
+  dpo: '00000000-0000-0000-0000-00000000010a',
+  rssi: '00000000-0000-0000-0000-00000000010b',
+  it: '00000000-0000-0000-0000-00000000010c',
+  formation: '00000000-0000-0000-0000-00000000010d',
+  qualite: '00000000-0000-0000-0000-00000000010e',
+  communication: '00000000-0000-0000-0000-00000000010f',
+  'elu-ca': '00000000-0000-0000-0000-000000000110',
+  'elu-cd': '00000000-0000-0000-0000-000000000111',
+  'elu-cd-president': '00000000-0000-0000-0000-000000000112',
+  'elu-cd-tresorier': '00000000-0000-0000-0000-000000000113',
+  'elu-cd-secretaire': '00000000-0000-0000-0000-000000000114',
+  delegue: '00000000-0000-0000-0000-000000000115',
+  benevole: '00000000-0000-0000-0000-000000000116',
+  'benevole-responsable': '00000000-0000-0000-0000-000000000117',
+  partenaire: '00000000-0000-0000-0000-000000000118',
+};
+
+/**
+ * The 19 personas provisioned in the `apfrd.onmicrosoft.com` test
+ * tenant on 2026-05-20, transcribed from
+ * `notes/test-tenant-role-assignments.md` (reverse view). The
+ * builder's contract is that these inputs round-trip to the
+ * expected `(privileges, roles, scopes)` triple — when the spec
+ * passes, every persona we documented in the ADR is exercised
+ * end-to-end.
+ *
+ * Scopes are stubbed to `[{ kind: 'unrestricted' }]` for every
+ * persona in v1 per ADR-0025 §"Sources of truth — apf_portal-side
+ * `user_scopes` table". The intended per-persona scopes
+ * (`etablissement:…`, `delegation:33`, …) land with the Prisma
+ * `user_scopes` table — the next PR after this skeleton.
+ */
+interface Persona {
+  readonly label: string;
+  readonly username: string;
+  readonly privileges: readonly string[]; // raw `roles` claim values
+  readonly roles: readonly FunctionalRole[];
+}
+
+const PERSONAS: readonly Persona[] = [
+  {
+    label: 'admin',
+    username: 'admin@apfrd.onmicrosoft.com',
+    privileges: ['Portal.Admin'],
+    roles: ['collaborateur', 'rh'],
+  },
+  {
+    label: 'directeur-bordeaux',
+    username: 'directeur-bordeaux@apfrd.onmicrosoft.com',
+    privileges: [],
+    roles: ['collaborateur', 'directeur-etablissement'],
+  },
+  {
+    label: 'directeur-complexe',
+    username: 'directeur-complexe@apfrd.onmicrosoft.com',
+    privileges: [],
+    roles: ['collaborateur', 'directeur-etablissement'],
+  },
+  {
+    label: 'rh-aquitaine',
+    username: 'rh-aquitaine@apfrd.onmicrosoft.com',
+    privileges: [],
+    roles: ['collaborateur', 'rh', 'formation'],
+  },
+  {
+    label: 'rh-siege',
+    username: 'rh-siege@apfrd.onmicrosoft.com',
+    privileges: [],
+    roles: ['collaborateur', 'rh', 'responsable-paie', 'comptable'],
+  },
+  {
+    label: 'collaborateur-simple',
+    username: 'collaborateur-simple@apfrd.onmicrosoft.com',
+    privileges: [],
+    roles: ['collaborateur'],
+  },
+  {
+    label: 'tresorier-bordeaux',
+    username: 'tresorier-bordeaux@apfrd.onmicrosoft.com',
+    privileges: [],
+    roles: ['elu-cd', 'elu-cd-tresorier'],
+  },
+  {
+    label: 'dpo',
+    username: 'dpo@apfrd.onmicrosoft.com',
+    privileges: ['Portal.DPO', 'Portal.Auditor'],
+    roles: ['collaborateur', 'dpo', 'qualite'],
+  },
+  {
+    label: 'it',
+    username: 'it@apfrd.onmicrosoft.com',
+    privileges: [],
+    roles: ['collaborateur', 'it'],
+  },
+  {
+    label: 'benevole-aquitaine',
+    username: 'benevole-aquitaine@apfrd.onmicrosoft.com',
+    privileges: [],
+    // Catalogue order: delegue (governance) precedes benevole +
+    // benevole-responsable (volunteer). The resolver re-sorts on
+    // catalogue order regardless of the Entra claim's order.
+    roles: ['delegue', 'benevole', 'benevole-responsable'],
+  },
+  {
+    label: 'chef-equipe-bordeaux',
+    username: 'chef-equipe-bordeaux@apfrd.onmicrosoft.com',
+    privileges: [],
+    roles: ['collaborateur', 'chef-equipe'],
+  },
+  {
+    label: 'chef-service-bordeaux',
+    username: 'chef-service-bordeaux@apfrd.onmicrosoft.com',
+    privileges: [],
+    roles: ['collaborateur', 'chef-service'],
+  },
+  {
+    label: 'directeur-territorial-aquitaine',
+    username: 'directeur-territorial-aquitaine@apfrd.onmicrosoft.com',
+    privileges: [],
+    roles: ['collaborateur', 'directeur-territorial'],
+  },
+  {
+    label: 'juriste-siege',
+    username: 'juriste-siege@apfrd.onmicrosoft.com',
+    privileges: [],
+    roles: ['collaborateur', 'juriste'],
+  },
+  {
+    label: 'rssi',
+    username: 'rssi@apfrd.onmicrosoft.com',
+    privileges: ['Portal.SecurityOfficer'],
+    roles: ['collaborateur', 'rssi'],
+  },
+  {
+    label: 'communication-siege',
+    username: 'communication-siege@apfrd.onmicrosoft.com',
+    privileges: [],
+    roles: ['collaborateur', 'communication'],
+  },
+  {
+    label: 'elu-ca-national',
+    username: 'elu-ca-national@apfrd.onmicrosoft.com',
+    privileges: [],
+    roles: ['elu-ca'],
+  },
+  {
+    label: 'president-cd-aquitaine',
+    username: 'president-cd-aquitaine@apfrd.onmicrosoft.com',
+    privileges: [],
+    roles: ['elu-cd', 'elu-cd-president'],
+  },
+  {
+    label: 'secretaire-cd-aquitaine',
+    username: 'secretaire-cd-aquitaine@apfrd.onmicrosoft.com',
+    privileges: [],
+    roles: ['elu-cd', 'elu-cd-secretaire'],
+  },
+];
+
+function makeUser(p: Persona): AuthenticatedUser {
+  return {
+    oid: `oid-${p.label}`,
+    tid: 'tenant-1',
+    username: p.username,
+    displayName: p.label,
+    amr: ['pwd', 'mfa'],
+    roles: [...p.privileges],
+    groups: p.roles.map((slug) => ROLE_GUID[slug]),
+  };
+}
+
+function makeBuilder(): {
+  builder: PrincipalBuilder;
+  scopeResolver: { resolve: jest.Mock };
+  logger: { log: jest.Mock; warn: jest.Mock; error: jest.Mock };
+} {
+  const rawMap: Record<string, FunctionalRole> = {};
+  for (const [slug, guid] of Object.entries(ROLE_GUID) as Array<[FunctionalRole, string]>) {
+    rawMap[guid] = slug;
+  }
+  const resolver = new EntraGroupToRoleResolver(parseEntraGroupMap(rawMap));
+  const scopeResolver = {
+    resolve: jest.fn().mockResolvedValue([{ kind: 'unrestricted' } as Scope]),
+  };
+  const logger = { log: jest.fn(), warn: jest.fn(), error: jest.fn() };
+  const builder = new PrincipalBuilder(
+    resolver,
+    scopeResolver as unknown as ScopeResolver,
+    logger as unknown as Logger,
+  );
+  return { builder, scopeResolver, logger };
+}
+
+describe('PrincipalBuilder — 19 test-tenant personas', () => {
+  for (const persona of PERSONAS) {
+    it(`builds the principal for ${persona.label}`, async () => {
+      const { builder } = makeBuilder();
+      const principal = await builder.build(makeUser(persona));
+      expect(principal.privileges).toEqual(persona.privileges);
+      expect(principal.roles).toEqual(persona.roles);
+      expect(principal.scopes).toEqual([{ kind: 'unrestricted' }]);
+      expect(principal.user.entraOid).toBe(`oid-${persona.label}`);
+      expect(principal.user.tenantId).toBe('tenant-1');
+      // amr passes through verbatim — MFA freshness checks read it
+      // off the principal per ADR-0011.
+      expect(principal.amr).toEqual(['pwd', 'mfa']);
+    });
+  }
+
+  it('asserts the 19 personas cover all 4 privileges + 23 of 24 functional roles', () => {
+    // Coverage check baked into the spec so a regression that
+    // drops a role from a persona is caught here, not at PR review.
+    // The intentional gap is `partenaire` (placeholder per ADR-0025).
+    const privilegesUsed = new Set(PERSONAS.flatMap((p) => p.privileges));
+    expect(privilegesUsed).toEqual(
+      new Set(['Portal.Admin', 'Portal.Auditor', 'Portal.SecurityOfficer', 'Portal.DPO']),
+    );
+    const rolesUsed = new Set(PERSONAS.flatMap((p) => p.roles));
+    expect(rolesUsed.size).toBe(23);
+    expect(rolesUsed.has('partenaire')).toBe(false);
+  });
+});
+
+describe('PrincipalBuilder — edge cases', () => {
+  it('returns an empty privileges array when the user has no app role assignment', async () => {
+    const { builder } = makeBuilder();
+    const user = makeUser({
+      label: 'anon',
+      username: 'anon@example',
+      privileges: [],
+      roles: ['collaborateur'],
+    });
+    const principal = await builder.build(user);
+    expect(principal.privileges).toEqual([]);
+  });
+
+  it('drops + warns on a claim value that is not a known privilege', async () => {
+    const { builder, logger } = makeBuilder();
+    const user = makeUser({
+      label: 'stale',
+      username: 'stale@example',
+      privileges: [],
+      roles: [],
+    });
+    // Force in a non-catalogue value the way an old assignment would.
+    const userWithDrift: AuthenticatedUser = {
+      ...user,
+      roles: ['Portal.Admin', 'Portal.GhostRole'],
+    };
+    const principal = await builder.build(userWithDrift);
+    expect(principal.privileges).toEqual(['Portal.Admin']);
+    expect(logger.warn).toHaveBeenCalledWith(
+      expect.objectContaining({
+        event: 'auth.unknown_privilege_claim',
+        value: 'Portal.GhostRole',
+      }),
+      'PrincipalBuilder',
+    );
+  });
+
+  it('drops + warns on an unknown group GUID (tenant misconfiguration)', async () => {
+    const { builder, logger } = makeBuilder();
+    const user = makeUser({
+      label: 'ghost-group',
+      username: 'ghost-group@example',
+      privileges: [],
+      roles: ['collaborateur'],
+    });
+    const userWithUnknownGroup: AuthenticatedUser = {
+      ...user,
+      groups: [...user.groups, 'ffffffff-ffff-ffff-ffff-ffffffffffff'],
+    };
+    const principal = await builder.build(userWithUnknownGroup);
+    expect(principal.roles).toEqual(['collaborateur']);
+    expect(logger.warn).toHaveBeenCalledWith(
+      expect.objectContaining({
+        event: 'auth.unknown_group_claim',
+        groupId: 'ffffffff-ffff-ffff-ffff-ffffffffffff',
+      }),
+      'PrincipalBuilder',
+    );
+  });
+
+  it('builds an empty-permissions principal when the user has no groups or roles', async () => {
+    const { builder } = makeBuilder();
+    const user = makeUser({
+      label: 'empty',
+      username: 'empty@example',
+      privileges: [],
+      roles: [],
+    });
+    const principal = await builder.build(user);
+    expect(principal.privileges).toEqual([]);
+    expect(principal.roles).toEqual([]);
+    // Scope resolver stub returns unrestricted — the v1 behaviour
+    // per ADR-0025 §331 until the user_scopes table lands.
+    expect(principal.scopes).toEqual([{ kind: 'unrestricted' }]);
+  });
+
+  it('asks the scope resolver to resolve by entraOid', async () => {
+    const { builder, scopeResolver } = makeBuilder();
+    await builder.build(
+      makeUser({
+        label: 'sr',
+        username: 'sr@example',
+        privileges: [],
+        roles: ['collaborateur'],
+      }),
+    );
+    expect(scopeResolver.resolve).toHaveBeenCalledWith({ entraOid: 'oid-sr' });
+  });
+});

apps/portal-bff/src/auth/principal-builder.ts

@@ -0,0 +1,107 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { Logger } from 'nestjs-pino';
+import { EntraGroupToRoleResolver, isPrivilege, type Principal, type Privilege } from 'shared-auth';
+import { ENTRA_GROUP_TO_ROLE_RESOLVER } from './entra-group-to-role.token';
+import { ScopeResolver } from './scope-resolver';
+import type { AuthenticatedUser } from './auth.service';
+
+/**
+ * Builds the session-resident `Principal` per
+ * [ADR-0025 §"Principal shape"](../../../../docs/decisions/0025-authorization-model-privileges-roles-scopes.md).
+ *
+ * Composes the three orthogonal axes once at sign-in:
+ *   - **Privileges** — pulled from the `roles` claim, filtered to
+ *     the closed `PRIVILEGES` catalogue. Unknown values are
+ *     dropped (with a WARN) rather than honoured: the BFF only
+ *     reasons about catalogue privileges, anything else is
+ *     either a tenant misconfiguration or a leftover from a v1+1
+ *     experiment that should not silently grant access.
+ *   - **Functional roles** — resolved from the `groups` claim via
+ *     `EntraGroupToRoleResolver`. Unknown GUIDs are logged at
+ *     WARN (per ADR-0025 §"Sources of truth — Entra-side
+ *     configuration") and ignored.
+ *   - **Scopes** — resolved by `ScopeResolver` from the portal-side
+ *     `user_scopes` table once ADR-0026 lands. v1 stubs to
+ *     `[{ kind: 'unrestricted' }]`.
+ *
+ * Built once per sign-in, not per request: the session payload
+ * carries the resolved `Principal` so guards can read it without
+ * re-doing the GUID lookup on every API call.
+ *
+ * `user.id` and `user.personId` are placeholders (= `entraOid`)
+ * until the `User` + `Person` schema (proposed ADR-0026) lands.
+ * The seam is here so the next PR populates the real UUIDs in one
+ * place, not in every guard.
+ */
+@Injectable()
+export class PrincipalBuilder {
+  constructor(
+    @Inject(ENTRA_GROUP_TO_ROLE_RESOLVER)
+    private readonly groupToRole: EntraGroupToRoleResolver,
+    private readonly scopes: ScopeResolver,
+    private readonly logger: Logger,
+  ) {}
+
+  async build(user: AuthenticatedUser): Promise<Principal> {
+    const privileges = filterPrivileges(user.roles, user.oid, this.logger);
+
+    const roles = this.groupToRole.resolve(user.groups, (groupId: string) => {
+      this.logger.warn(
+        {
+          event: 'auth.unknown_group_claim',
+          oid: user.oid,
+          groupId,
+        },
+        'PrincipalBuilder',
+      );
+    });
+
+    const scopes = await this.scopes.resolve({ entraOid: user.oid });
+
+    return {
+      user: {
+        // Real UUIDs land with ADR-0026's User + Person schema.
+        // Until then `entraOid` is the closest thing to a stable
+        // portal identity, so callers that key on `principal.user.id`
+        // get a usable value today and a real one later.
+        id: user.oid,
+        personId: user.oid,
+        entraOid: user.oid,
+        tenantId: user.tid,
+        displayName: user.displayName,
+      },
+      privileges,
+      roles,
+      scopes,
+      amr: user.amr,
+    };
+  }
+}
+
+function filterPrivileges(
+  rawRoles: readonly string[],
+  oid: string,
+  logger: Logger,
+): ReadonlyArray<Privilege> {
+  const out: Privilege[] = [];
+  for (const value of rawRoles) {
+    if (isPrivilege(value)) {
+      out.push(value);
+    } else {
+      // A value in the `roles` claim that is not a known privilege
+      // is either a leftover from a different app registration, a
+      // typo in the Entra manifest, or a future privilege not yet
+      // in the catalogue. None of those should silently grant
+      // access — drop with a WARN so an operator can investigate.
+      logger.warn(
+        {
+          event: 'auth.unknown_privilege_claim',
+          oid,
+          value,
+        },
+        'PrincipalBuilder',
+      );
+    }
+  }
+  return out;
+}

apps/portal-bff/src/auth/require-mfa.guard.spec.ts

@@ -53,6 +53,7 @@ const USER = {
   displayName: 'Jane',
   amr: ['pwd', 'mfa'],
   roles: ['admin'],
+  groups: [],
 };
 
 describe('RequireMfaGuard', () => {

apps/portal-bff/src/auth/scope-resolver.ts

@@ -0,0 +1,47 @@
+import { Injectable } from '@nestjs/common';
+import type { Scope } from 'shared-auth';
+
+/**
+ * Resolves the portal-side scopes for a user being signed in.
+ *
+ * Per [ADR-0025 §"Sources of truth — apf_portal-side `user_scopes`
+ * table"](../../../../docs/decisions/0025-authorization-model-privileges-roles-scopes.md),
+ * scopes are *not* carried by Entra: they will live in a portal
+ * `user_scopes` Prisma table (proposed ADR-0026), queried by Entra
+ * `oid` at sign-in. Each row materialises one `Scope` entry on the
+ * session principal.
+ *
+ * The seam is here in v1 so the next PR replaces only the
+ * implementation, leaving the call-site in `PrincipalBuilder`
+ * untouched. The v1 implementation (`StubScopeResolver`) always
+ * returns `[{ kind: 'unrestricted' }]` per ADR-0025 §331 — until
+ * the Prisma table lands the test tenant runs against a single
+ * "see everything" scope; the absence of fine-grained scoping is
+ * acceptable because guards consuming `@RequireScope` are not in
+ * the codebase yet.
+ */
+export abstract class ScopeResolver {
+  abstract resolve(input: { entraOid: string }): Promise<ReadonlyArray<Scope>>;
+}
+
+/**
+ * v1 stub — returns `unrestricted` for every user. Per ADR-0025
+ * §"Sources of truth — apf_portal-side `user_scopes` table" the
+ * real implementation queries `user_scopes WHERE userId = ?`; that
+ * lands with the `Person` + `User` schema (proposed ADR-0026) and
+ * the seed PR that follows.
+ *
+ * Deliberately not an in-memory hard-coded persona-keyed map: the
+ * 19 test personas have *intended* scopes (see
+ * `notes/test-tenant-role-assignments.md`) but those scopes have
+ * no guard consuming them yet, so per-persona stub data would be
+ * write-only documentation. When ADR-0026 lands, the seed PR
+ * populates `user_scopes`; this class is replaced by a
+ * Prisma-backed implementation in the same change.
+ */
+@Injectable()
+export class StubScopeResolver extends ScopeResolver {
+  override resolve(): Promise<ReadonlyArray<Scope>> {
+    return Promise.resolve([{ kind: 'unrestricted' }]);
+  }
+}

apps/portal-bff/src/auth/session-establisher.service.spec.ts

@@ -1,9 +1,11 @@
 import type { Request, Response } from 'express';
 import type { Logger } from 'nestjs-pino';
+import type { Principal } from 'shared-auth';
 import type { AuditWriter } from '../audit/audit.service';
 import type { UserSessionIndexService } from '../session/user-session-index.service';
 import type { UserDirectoryService } from '../users/user-directory.service';
 import type { AuthenticatedUser } from './auth.service';
+import type { PrincipalBuilder } from './principal-builder';
 import { SessionEstablisher } from './session-establisher.service';
 
 const USER: AuthenticatedUser = {
@@ -13,6 +15,7 @@ const USER: AuthenticatedUser = {
   displayName: 'Jane Doe',
   amr: ['pwd', 'mfa'],
   roles: [],
+  groups: [],
 };
 
 function makeReqStub(opts?: { sessionID?: string; sessionUser?: AuthenticatedUser }): Request {
@@ -53,8 +56,23 @@ interface Fixture {
   audit: { signIn: jest.Mock; signOut: jest.Mock };
   directory: { recordSignIn: jest.Mock };
   logger: ReturnType<typeof makeLoggerStub>;
+  principalBuilder: { build: jest.Mock };
 }
 
+const STUB_PRINCIPAL: Principal = {
+  user: {
+    id: USER.oid,
+    personId: USER.oid,
+    entraOid: USER.oid,
+    tenantId: USER.tid,
+    displayName: USER.displayName,
+  },
+  privileges: [],
+  roles: [],
+  scopes: [{ kind: 'unrestricted' }],
+  amr: USER.amr,
+};
+
 function makeFixture(): Fixture {
   const index = {
     add: jest.fn().mockResolvedValue(undefined),
@@ -69,13 +87,17 @@ function makeFixture(): Fixture {
     recordSignIn: jest.fn().mockResolvedValue(undefined),
   };
   const logger = makeLoggerStub();
+  const principalBuilder = {
+    build: jest.fn().mockResolvedValue(STUB_PRINCIPAL),
+  };
   const est = new SessionEstablisher(
     logger as unknown as Logger,
     index as unknown as UserSessionIndexService,
     audit as unknown as AuditWriter,
     directory as unknown as UserDirectoryService,
+    principalBuilder as unknown as PrincipalBuilder,
   );
-  return { est, index, audit, directory, logger };
+  return { est, index, audit, directory, logger, principalBuilder };
 }
 
 describe('SessionEstablisher.establish', () => {
@@ -97,6 +119,20 @@ describe('SessionEstablisher.establish', () => {
     expect((sess['csrfToken'] as string).length).toBeGreaterThan(20);
   });
 
+  it('builds the authorization principal and stamps mfaVerifiedAt on it (ADR-0025)', async () => {
+    const { est, principalBuilder } = makeFixture();
+    const req = makeReqStub();
+    const res = makeResStub();
+    await est.establish({ user: USER, req, res, surface: 'user' });
+    expect(principalBuilder.build).toHaveBeenCalledWith(USER);
+    const sess = (req as unknown as { session: Record<string, unknown> }).session;
+    const principal = sess['principal'] as Principal;
+    expect(principal).toBeDefined();
+    expect(principal.user.entraOid).toBe(USER.oid);
+    expect(principal.scopes).toEqual([{ kind: 'unrestricted' }]);
+    expect(principal.mfaVerifiedAt).toBe(sess['createdAt']);
+  });
+
   it('saves the session before returning (no race with the controller redirect)', async () => {
     const { est } = makeFixture();
     const req = makeReqStub();

apps/portal-bff/src/auth/session-establisher.service.ts

@@ -8,6 +8,7 @@ import { readSessionTimeouts } from '../session/session-cookie';
 import { UserSessionIndexService } from '../session/user-session-index.service';
 import { UserDirectoryService } from '../users/user-directory.service';
 import type { AuthenticatedUser } from './auth.service';
+import { PrincipalBuilder } from './principal-builder';
 
 export type AuthSurface = 'user' | 'admin';
 
@@ -47,6 +48,7 @@ export class SessionEstablisher {
     private readonly userSessionIndex: UserSessionIndexService,
     private readonly audit: AuditWriter,
     private readonly userDirectory: UserDirectoryService,
+    private readonly principalBuilder: PrincipalBuilder,
   ) {}
 
   async establish(opts: {
@@ -79,6 +81,14 @@ export class SessionEstablisher {
     // does not re-validate factors. Refreshed by future step-up
     // re-auth flows.
     req.session.mfaVerifiedAt = now;
+    // Authorization principal per ADR-0025: composes the three
+    // axes (privileges / functional roles / scopes) once at
+    // sign-in so guards read a single coherent shape instead of
+    // re-parsing claims on every request. Built before the
+    // session is persisted so a Redis hiccup either persists
+    // everything or nothing.
+    const principal = await this.principalBuilder.build(user);
+    req.session.principal = { ...principal, mfaVerifiedAt: now };
 
     await saveSession(req);
 

apps/portal-bff/src/config/load-entra-group-map.spec.ts

@@ -0,0 +1,93 @@
+import { mkdtempSync, writeFileSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { EntraGroupMapError } from 'shared-auth';
+import { loadEntraGroupToRoleResolver } from './load-entra-group-map';
+
+function tmpFile(name: string, contents: string): string {
+  const dir = mkdtempSync(join(tmpdir(), 'entra-map-'));
+  const path = join(dir, name);
+  writeFileSync(path, contents, 'utf8');
+  return path;
+}
+
+function noopWarn(): { onWarn: jest.Mock } {
+  return { onWarn: jest.fn() };
+}
+
+describe('loadEntraGroupToRoleResolver', () => {
+  it('returns an empty resolver and warns when ENTRA_GROUP_MAP_PATH is unset', () => {
+    const { onWarn } = noopWarn();
+    const { resolver, sourcePath } = loadEntraGroupToRoleResolver({
+      env: {},
+      onWarn,
+    });
+    expect(resolver.size).toBe(0);
+    expect(sourcePath).toBeNull();
+    expect(onWarn).toHaveBeenCalledWith('auth.entra_group_map_path_unset', expect.any(Object));
+  });
+
+  it('returns an empty resolver and warns when the file cannot be read', () => {
+    const { onWarn } = noopWarn();
+    const { resolver, sourcePath } = loadEntraGroupToRoleResolver({
+      env: { ENTRA_GROUP_MAP_PATH: '/tmp/definitely-not-a-real-path-xyz.json' },
+      onWarn,
+    });
+    expect(resolver.size).toBe(0);
+    expect(sourcePath).toBe('/tmp/definitely-not-a-real-path-xyz.json');
+    expect(onWarn).toHaveBeenCalledWith(
+      'auth.entra_group_map_file_unreadable',
+      expect.objectContaining({ path: '/tmp/definitely-not-a-real-path-xyz.json' }),
+    );
+  });
+
+  it('throws on malformed JSON', () => {
+    const path = tmpFile('bad.json', '{ not json');
+    expect(() =>
+      loadEntraGroupToRoleResolver({
+        env: { ENTRA_GROUP_MAP_PATH: path },
+        onWarn: jest.fn(),
+      }),
+    ).toThrow(EntraGroupMapError);
+  });
+
+  it('throws when the JSON is not an object', () => {
+    const path = tmpFile('arr.json', '["collaborateur"]');
+    expect(() =>
+      loadEntraGroupToRoleResolver({
+        env: { ENTRA_GROUP_MAP_PATH: path },
+        onWarn: jest.fn(),
+      }),
+    ).toThrow(EntraGroupMapError);
+  });
+
+  it('throws when a value is not a string', () => {
+    const path = tmpFile(
+      'bad-val.json',
+      JSON.stringify({ '11111111-1111-1111-1111-111111111111': 42 }),
+    );
+    expect(() =>
+      loadEntraGroupToRoleResolver({
+        env: { ENTRA_GROUP_MAP_PATH: path },
+        onWarn: jest.fn(),
+      }),
+    ).toThrow(EntraGroupMapError);
+  });
+
+  it('returns a populated resolver on a valid map', () => {
+    const path = tmpFile(
+      'good.json',
+      JSON.stringify({
+        '11111111-1111-1111-1111-111111111111': 'collaborateur',
+        '22222222-2222-2222-2222-222222222222': 'rh',
+      }),
+    );
+    const { resolver, sourcePath } = loadEntraGroupToRoleResolver({
+      env: { ENTRA_GROUP_MAP_PATH: path },
+      onWarn: jest.fn(),
+    });
+    expect(resolver.size).toBe(2);
+    expect(sourcePath).toBe(path);
+    expect(resolver.coveredRoles()).toEqual(['collaborateur', 'rh']);
+  });
+});

apps/portal-bff/src/config/load-entra-group-map.ts

@@ -0,0 +1,98 @@
+import { readFileSync } from 'node:fs';
+import { isAbsolute, resolve } from 'node:path';
+import { EntraGroupMapError, EntraGroupToRoleResolver, parseEntraGroupMap } from 'shared-auth';
+
+/**
+ * Outcome of `loadEntraGroupToRoleResolver` — paired with the
+ * source path (when set) so the boot log can name the file that
+ * was loaded, even when the resolver itself ends up empty.
+ */
+export interface EntraGroupResolverLoadResult {
+  readonly resolver: EntraGroupToRoleResolver;
+  /** `null` when no path was configured (env var unset). */
+  readonly sourcePath: string | null;
+}
+
+/**
+ * Loads the Entra group-GUID → role-slug map at BFF boot per
+ * [ADR-0025 §"Sources of truth — Entra-side configuration"](../../../../docs/decisions/0025-authorization-model-privileges-roles-scopes.md).
+ *
+ * Sourcing precedence:
+ *   1. `ENTRA_GROUP_MAP_PATH` env var → JSON file path (absolute,
+ *      or relative to `cwd`).
+ *   2. Unset → empty resolver, WARN logged at boot. Sign-in still
+ *      works but every user gets an empty `roles[]` until the
+ *      operator wires up the file. Acceptable for fresh dev
+ *      environments; production should always set the var.
+ *
+ * Failure modes:
+ *   - File configured but unreadable / missing → empty resolver,
+ *     WARN. Same fail-soft posture: an operator pointing at the
+ *     wrong path should not block every sign-in.
+ *   - File present but malformed (bad JSON, wrong shape, unknown
+ *     slug, duplicate GUID) → throws. A misconfigured map is a
+ *     hard-fail because the alternative is silently mis-resolving
+ *     a role.
+ *
+ * The function never reads `process.env` outside the documented
+ * key and never mutates it.
+ */
+export function loadEntraGroupToRoleResolver(opts: {
+  cwd?: string;
+  env?: NodeJS.ProcessEnv;
+  onWarn: (event: string, payload: Record<string, unknown>) => void;
+}): EntraGroupResolverLoadResult {
+  const env = opts.env ?? process.env;
+  const cwd = opts.cwd ?? process.cwd();
+  const rawPath = env['ENTRA_GROUP_MAP_PATH'];
+
+  if (typeof rawPath !== 'string' || rawPath === '') {
+    opts.onWarn('auth.entra_group_map_path_unset', {
+      hint: 'set ENTRA_GROUP_MAP_PATH to infra/<env>-tenant.entra.json — sign-in will succeed but resolve zero functional roles until configured',
+    });
+    return { resolver: new EntraGroupToRoleResolver(new Map()), sourcePath: null };
+  }
+
+  const absolutePath = isAbsolute(rawPath) ? rawPath : resolve(cwd, rawPath);
+
+  let raw: string;
+  try {
+    raw = readFileSync(absolutePath, 'utf8');
+  } catch (err) {
+    opts.onWarn('auth.entra_group_map_file_unreadable', {
+      path: absolutePath,
+      message: err instanceof Error ? err.message : String(err),
+    });
+    return { resolver: new EntraGroupToRoleResolver(new Map()), sourcePath: absolutePath };
+  }
+
+  let parsed: unknown;
+  try {
+    parsed = JSON.parse(raw);
+  } catch (err) {
+    throw new EntraGroupMapError(
+      `Entra group map at ${absolutePath} is not valid JSON: ${
+        err instanceof Error ? err.message : String(err)
+      }`,
+    );
+  }
+
+  if (parsed === null || typeof parsed !== 'object' || Array.isArray(parsed)) {
+    throw new EntraGroupMapError(
+      `Entra group map at ${absolutePath} must be a JSON object keyed on group GUID.`,
+    );
+  }
+
+  const stringified: Record<string, string> = {};
+  for (const [key, value] of Object.entries(parsed as Record<string, unknown>)) {
+    if (typeof value !== 'string') {
+      throw new EntraGroupMapError(
+        `Entra group map entry "${key}" in ${absolutePath} must be a string (the role slug); got ${typeof value}.`,
+      );
+    }
+    stringified[key] = value;
+  }
+
+  const map = parseEntraGroupMap(stringified);
+  return { resolver: new EntraGroupToRoleResolver(map), sourcePath: absolutePath };
+}

apps/portal-bff/src/grpc/ai-bridge/ai-bridge.controller.spec.ts

@@ -71,6 +71,7 @@ const USER: AuthenticatedUser = {
   displayName: 'Alice',
   amr: ['pwd', 'mfa'],
   roles: ['admin'],
+  groups: [],
 };
 
 // ---- Fake gRPC server (Chat + Rag + Models) -------------------

apps/portal-bff/src/session/session.types.ts

@@ -1,3 +1,4 @@
+import type { Principal } from 'shared-auth';
 import type { AuthenticatedUser } from '../auth/auth.service';
 
 /**
@@ -18,6 +19,26 @@ import type { AuthenticatedUser } from '../auth/auth.service';
 declare module 'express-session' {
   interface SessionData {
     user?: AuthenticatedUser;
+    /**
+     * Authorization principal per
+     * [ADR-0025 §"Principal shape"](../../../../docs/decisions/0025-authorization-model-privileges-roles-scopes.md).
+     * Built once at sign-in by `PrincipalBuilder` from the three
+     * source claims (Entra `roles` for privileges, Entra `groups`
+     * for functional roles, portal `user_scopes` for scopes) and
+     * read by the upcoming `@RequirePrivilege` / `@RequireRole` /
+     * `@RequireScope` guards on every request.
+     *
+     * Kept alongside `user` rather than replacing it: the audit
+     * module and the AI-bridge controller still key on
+     * `user.oid` / `user.tid` directly and would be churn-only
+     * to migrate. New consumers should reach for `principal`.
+     *
+     * Optional in the type — sessions persisted before this field
+     * existed will have it undefined. Guards must treat the
+     * missing-principal case the same as "no privileges, no roles,
+     * no scopes" rather than crashing.
+     */
+    principal?: Principal;
     /**
      * Epoch ms at which the BFF created this session. Posed by the
      * callback at the same time as `user`. Lets the absolute-timeout

apps/portal-bff/tsconfig.app.json

@@ -11,5 +11,10 @@
     "ignoreDeprecations": "5.0"
   },
   "include": ["src/**/*.ts"],
-  "exclude": ["jest.config.ts", "jest.config.cts", "src/**/*.spec.ts", "src/**/*.test.ts"]
+  "exclude": ["jest.config.ts", "jest.config.cts", "src/**/*.spec.ts", "src/**/*.test.ts"],
+  "references": [
+    {
+      "path": "../../libs/shared/auth"
+    }
+  ]
 }