diff --git a/src/modules/auth/auth.controller.ts b/src/modules/auth/auth.controller.ts
index 665729f..7807ab9 100644
--- a/src/modules/auth/auth.controller.ts
+++ b/src/modules/auth/auth.controller.ts
@@ -37,6 +37,9 @@ import {
   moduleGateSeqid,
   isModuleAllowed,
   isAdmin,
+  tenantOrchestApiHost,
+  isAllowedOrchestApiHost,
+  namespaceModule,
 } from './orchest-identity';
 import {
   Authenticated,
@@ -567,14 +570,54 @@ export class AuthController {
       return res.status(403).send();
     }
 
+    const adminUser = isAdmin(
+      perms,
+      parseAdminSeqids(process.env.ORCHEST_ADMIN_PERMISSION_SEQIDS),
+    );
+
     res.set('X-Auth-User', String(payload.user_id));
     res.set('X-Auth-Username', String(payload.username ?? ''));
-    if (
-      isAdmin(perms, parseAdminSeqids(process.env.ORCHEST_ADMIN_PERMISSION_SEQIDS))
-    ) {
+    if (adminUser) {
       res.set('X-Auth-Roles', 'admin');
     }
 
+    // Service-ingress caller: the orchest-api-authored annotation carries the
+    // scope. Authorize per-project against the tenant's orchest-api. A
+    // param-less request is the webserver-ingress case → identity only.
+    const permission = req.query?.permission as string | undefined;
+    const projectUuid = req.query?.project_uuid as string | undefined;
+    if (permission) {
+      // All-or-nothing: an incomplete annotation must not silently skip the
+      // per-project check.
+      if (!projectUuid) {
+        return res.status(403).send();
+      }
+      const module = namespaceModule(process.env.ORCHEST_NAMESPACE_MODULE);
+      const host = tenantOrchestApiHost(
+        String(payload.customer_name ?? ''),
+        module,
+      );
+      if (!isAllowedOrchestApiHost(host)) {
+        return res.status(403).send();
+      }
+      const identityHeaders: Record<string, string> = {
+        'X-Auth-User': String(payload.user_id),
+        'X-Auth-Username': String(payload.username ?? ''),
+      };
+      if (adminUser) {
+        identityHeaders['X-Auth-Roles'] = 'admin';
+      }
+      const decision = await this.authClient.authorizeOrchestServiceAccess({
+        host,
+        permission,
+        projectUuid,
+        headers: identityHeaders,
+      });
+      if (decision === 'deny') return res.status(403).send();
+      if (decision === 'error') return res.status(502).send();
+      // 'allow' falls through to the 200 (identity headers already set).
+    }
+
     return res.status(200).send();
   }
 }
diff --git a/src/modules/auth/auth.service.ts b/src/modules/auth/auth.service.ts
index 8ca6844..37f3f61 100644
--- a/src/modules/auth/auth.service.ts
+++ b/src/modules/auth/auth.service.ts
@@ -9,6 +9,7 @@ import {
 import { ClientGrpc } from '@nestjs/microservices';
 import { DadosferaLogger } from '@dadosfera/dadosfera-logs';
 import { lastValueFrom } from 'rxjs';
+import axios from 'axios';
 
 import { ProtoServices } from '@dadosfera/protospack-v2/dist/lib/Duc';
 import {
@@ -497,4 +498,33 @@ export class AuthClientService implements OnModuleInit {
 
     return;
   }
+
+  /**
+   * Ask a tenant's orchest-api whether the acting user holds `permission` on
+   * `projectUuid` (the per-service authz half of /auth/module-identity).
+   * Fail-closed: any error / unexpected status → 'error' (the route denies).
+   */
+  public async authorizeOrchestServiceAccess(args: {
+    host: string;
+    permission: string;
+    projectUuid?: string;
+    headers: Record<string, string>;
+  }): Promise<'allow' | 'deny' | 'error'> {
+    const params: Record<string, string> = { permission: args.permission };
+    if (args.projectUuid) params.project_uuid = args.projectUuid;
+    try {
+      const resp = await axios.get(`http://${args.host}/api/authz/check`, {
+        params,
+        headers: args.headers,
+        timeout: 5000,
+        // Never throw on 4xx/5xx; branch on the status ourselves.
+        validateStatus: () => true,
+      });
+      if (resp.status === 200) return 'allow';
+      if (resp.status === 403) return 'deny';
+      return 'error';
+    } catch (e) {
+      return 'error';
+    }
+  }
 }
diff --git a/src/modules/auth/module-identity.controller.spec.ts b/src/modules/auth/module-identity.controller.spec.ts
index 7f1830a..60a9fc9 100644
--- a/src/modules/auth/module-identity.controller.spec.ts
+++ b/src/modules/auth/module-identity.controller.spec.ts
@@ -125,3 +125,82 @@ describe('GET /auth/module-identity — identity', () => {
     expect(r._headers['X-Auth-Roles']).toBe('admin');
   });
 });
+
+describe('GET /auth/module-identity — per-service authz', () => {
+  let controller: AuthController;
+  const auth = {
+    verifyAccessToken: jest.fn(),
+    authorizeOrchestServiceAccess: jest.fn(),
+  } as unknown as AuthClientService;
+
+  const q = { permission: 'session.open', project_uuid: 'p-1' };
+
+  beforeEach(async () => {
+    jest.resetAllMocks();
+    process.env.ORCHEST_MODULE_PERMISSION_SEQID = '31';
+    process.env.ORCHEST_ADMIN_PERMISSION_SEQIDS = '34';
+    process.env.ORCHEST_NAMESPACE_MODULE = 'intelli';
+    controller = await makeController(auth);
+    (auth.verifyAccessToken as jest.Mock).mockResolvedValue({
+      user_id: 'u-1',
+      username: 'alice',
+      permissions: [31],
+      customer_name: 'acme',
+    });
+  });
+
+  it('has grant → 200 and calls the tenant host', async () => {
+    (auth.authorizeOrchestServiceAccess as jest.Mock).mockResolvedValue('allow');
+    const r = res();
+    await controller.moduleIdentity(req('tok', q), r);
+    expect(r._status).toBe(200);
+    expect(auth.authorizeOrchestServiceAccess).toHaveBeenCalledWith(
+      expect.objectContaining({
+        host: 'orchest-api.orchest-intelli-acme.svc.cluster.local',
+        permission: 'session.open',
+        projectUuid: 'p-1',
+      }),
+    );
+  });
+
+  it('lacks grant → 403', async () => {
+    (auth.authorizeOrchestServiceAccess as jest.Mock).mockResolvedValue('deny');
+    const r = res();
+    await controller.moduleIdentity(req('tok', q), r);
+    expect(r._status).toBe(403);
+  });
+
+  it('orchest-api error → 502 (fail-closed)', async () => {
+    (auth.authorizeOrchestServiceAccess as jest.Mock).mockResolvedValue('error');
+    const r = res();
+    await controller.moduleIdentity(req('tok', q), r);
+    expect(r._status).toBe(502);
+  });
+
+  it('permission without project_uuid → 403 (all-or-nothing)', async () => {
+    const r = res();
+    await controller.moduleIdentity(req('tok', { permission: 'session.open' }), r);
+    expect(r._status).toBe(403);
+    expect(auth.authorizeOrchestServiceAccess).not.toHaveBeenCalled();
+  });
+
+  it('no authz params → 200 identity-only (webserver case)', async () => {
+    const r = res();
+    await controller.moduleIdentity(req('tok', {}), r);
+    expect(r._status).toBe(200);
+    expect(auth.authorizeOrchestServiceAccess).not.toHaveBeenCalled();
+  });
+
+  it('malformed customer_name → host fails allowlist → 403, no call', async () => {
+    (auth.verifyAccessToken as jest.Mock).mockResolvedValue({
+      user_id: 'u-1',
+      username: 'alice',
+      permissions: [31],
+      customer_name: '',
+    });
+    const r = res();
+    await controller.moduleIdentity(req('tok', q), r);
+    expect(r._status).toBe(403);
+    expect(auth.authorizeOrchestServiceAccess).not.toHaveBeenCalled();
+  });
+});