diff --git a/server/src/nest/addons/mcp-addon-gate.ts b/server/src/nest/addons/mcp-addon-gate.ts
new file mode 100644
index 000000000..4cb30d37b
--- /dev/null
+++ b/server/src/nest/addons/mcp-addon-gate.ts
@@ -0,0 +1,19 @@
+import type { RequestHandler } from 'express';
+import { AddonsService } from './addons.service';
+import { ADDON_IDS } from '../../addons';
+
+/**
+ * Gate: 404 (empty body) when the MCP addon is disabled (M2 — prevents feature
+ * fingerprinting). A factory over the injected AddonsService rather than a
+ * middleware class: consumers build it inside their module's configure() and
+ * hand the bare RequestHandler to consumer.apply() ahead of the SDK routers.
+ */
+export function createMcpAddonGate(addons: AddonsService): RequestHandler {
+  return (_req, res, next) => {
+    if (!addons.isAddonEnabled(ADDON_IDS.MCP)) {
+      res.status(404).end();
+      return;
+    }
+    next();
+  };
+}
diff --git a/server/src/mcp/oauthProvider.ts b/server/src/nest/oauth/oauth-sdk.provider.ts
similarity index 77%
rename from server/src/mcp/oauthProvider.ts
rename to server/src/nest/oauth/oauth-sdk.provider.ts
index bd6843a30..1f44dcc67 100644
--- a/server/src/mcp/oauthProvider.ts
+++ b/server/src/nest/oauth/oauth-sdk.provider.ts
@@ -1,36 +1,24 @@
+import { Injectable } from '@nestjs/common';
 import type { Response } from 'express';
-import type { OAuthServerProvider } from '@modelcontextprotocol/sdk/server/auth/provider';
+import type { OAuthServerProvider, AuthorizationParams } from '@modelcontextprotocol/sdk/server/auth/provider';
 import type { OAuthClientInformationFull, OAuthTokenRevocationRequest, OAuthTokens } from '@modelcontextprotocol/sdk/shared/auth';
 import type { AuthInfo } from '@modelcontextprotocol/sdk/server/auth/types';
-import type { AuthorizationParams } from '@modelcontextprotocol/sdk/server/auth/provider';
 import type { OAuthRegisteredClientsStore } from '@modelcontextprotocol/sdk/server/auth/clients';
 import { InvalidClientMetadataError, ServerError } from '@modelcontextprotocol/sdk/server/auth/errors';
-import { db } from '../db/database';
-import {
-    createOAuthClient,
-    consumeAuthCode,
-    issueTokens,
-    refreshTokens,
-    revokeToken as serviceRevokeToken,
-    verifyPKCE,
-    getUserByAccessToken,
-} from '../nest/oauth/oauth.bridge';
-import { ALL_SCOPES } from './scopes';
-import { getMcpSafeUrl } from '../app-config';
-import { writeAudit } from '../nest/audit/audit.bridge';
+import { OauthService } from './oauth.service';
+import { AuditService } from '../audit/audit.service';
+import { ALL_SCOPES } from '../../mcp/scopes';
+import { getMcpSafeUrl } from '../../app-config';
 
-// ---------------------------------------------------------------------------
-// DB row type (mirrors oauthService.ts)
-// ---------------------------------------------------------------------------
-
-interface OAuthClientRow {
-    client_id: string;
-    name: string;
-    redirect_uris: string;   // JSON array
-    allowed_scopes: string;  // JSON array
-    is_public: number;       // 0 | 1
-    created_via: string;
-}
+/**
+ * TREK's adapters behind the MCP SDK's OAuth server interfaces, wrapping the
+ * injected OauthService. The SDK's authorizationHandler / clientRegistrationHandler
+ * Express routers are built over these instances in OauthModule.configure().
+ *
+ * Pending authorization codes stay module-scoped in oauth.pending-codes.ts: the
+ * consent controller writes a code through the container singleton and
+ * exchangeAuthorizationCode reads it back through the same injected singleton.
+ */
 
 // ---------------------------------------------------------------------------
 // Redirect URI validation (mirrors oauth.ts DCR checks)
@@ -60,7 +48,7 @@ function assertValidRedirectUris(uris: string[]): void {
 // Row → SDK client info shape
 // ---------------------------------------------------------------------------
 
-function rowToInfo(row: OAuthClientRow): OAuthClientInformationFull {
+function rowToInfo(row: NonNullable<ReturnType<OauthService['getSdkClient']>>): OAuthClientInformationFull {
     return {
         client_id: row.client_id,
         client_name: row.name,
@@ -76,13 +64,14 @@ function rowToInfo(row: OAuthClientRow): OAuthClientInformationFull {
 // Clients store
 // ---------------------------------------------------------------------------
 
-export const trekClientsStore: OAuthRegisteredClientsStore = {
+@Injectable()
+export class TrekClientsStore implements OAuthRegisteredClientsStore {
+    constructor(private readonly oauth: OauthService) {}
+
     async getClient(clientId: string): Promise<OAuthClientInformationFull | undefined> {
-        const row = db.prepare(
-            'SELECT client_id, name, redirect_uris, allowed_scopes, is_public, created_via FROM oauth_clients WHERE client_id = ?'
-        ).get(clientId) as OAuthClientRow | undefined;
+        const row = this.oauth.getSdkClient(clientId);
         return row ? rowToInfo(row) : undefined;
-    },
+    }
 
     async registerClient(
         metadata: Omit<OAuthClientInformationFull, 'client_id' | 'client_id_issued_at'>,
@@ -99,7 +88,7 @@ export const trekClientsStore: OAuthRegisteredClientsStore = {
         const scopes = rawScopes.filter(s => (ALL_SCOPES as string[]).includes(s));
         if (scopes.length === 0) throw new InvalidClientMetadataError('No valid scopes requested');
 
-        const result = createOAuthClient(null, name, uris, scopes, null, { isPublic, createdVia: 'dcr' });
+        const result = this.oauth.createOAuthClient(null, name, uris, scopes, null, { isPublic, createdVia: 'dcr' });
         if (result.error) throw new InvalidClientMetadataError(result.error);
 
         const c = result.client!;
@@ -113,15 +102,22 @@ export const trekClientsStore: OAuthRegisteredClientsStore = {
             response_types: ['code'],
             ...(c.client_secret ? { client_secret: c.client_secret as string, client_secret_expires_at: 0 } : {}),
         };
-    },
-};
+    }
+}
 
 // ---------------------------------------------------------------------------
 // OAuthServerProvider
 // ---------------------------------------------------------------------------
 
-export const trekOAuthProvider: OAuthServerProvider = {
-    get clientsStore() { return trekClientsStore; },
+@Injectable()
+export class TrekOAuthProvider implements OAuthServerProvider {
+    constructor(
+        private readonly clients: TrekClientsStore,
+        private readonly oauth: OauthService,
+        private readonly audit: AuditService,
+    ) {}
+
+    get clientsStore(): OAuthRegisteredClientsStore { return this.clients; }
 
     // Redirects browser to the SPA consent page with OAuth params forwarded.
     async authorize(client: OAuthClientInformationFull, params: AuthorizationParams, res: Response): Promise<void> {
@@ -149,15 +145,15 @@ export const trekOAuthProvider: OAuthServerProvider = {
 
         const base = getMcpSafeUrl().replace(/\/+$/, '');
         res.redirect(302, `${base}/oauth/consent?${qs.toString()}`);
-    },
+    }
 
     // Not called because skipLocalPkceValidation = true.
     // PKCE verification is done inline in exchangeAuthorizationCode.
-    skipLocalPkceValidation: true,
+    readonly skipLocalPkceValidation = true;
 
     async challengeForAuthorizationCode(_client: OAuthClientInformationFull, _code: string): Promise<string> {
         throw new ServerError('PKCE validation is handled by the provider directly');
-    },
+    }
 
     async exchangeAuthorizationCode(
         client: OAuthClientInformationFull,
@@ -166,7 +162,7 @@ export const trekOAuthProvider: OAuthServerProvider = {
         redirectUri?: string,
         resource?: URL,
     ): Promise<OAuthTokens> {
-        const pending = consumeAuthCode(code);
+        const pending = this.oauth.consumeAuthCode(code);
         if (!pending || pending.clientId !== client.client_id)
             throw new Error('Authorization grant is invalid.');
 
@@ -177,18 +173,18 @@ export const trekOAuthProvider: OAuthServerProvider = {
         if (pending.resource && resourceStr && pending.resource !== resourceStr)
             throw new Error('Authorization grant is invalid.');
 
-        if (codeVerifier && !verifyPKCE(codeVerifier, pending.codeChallenge))
+        if (codeVerifier && !this.oauth.verifyPKCE(codeVerifier, pending.codeChallenge))
             throw new Error('Authorization grant is invalid.');
 
-        const tokens = issueTokens(client.client_id, pending.userId, pending.scopes, null, pending.resource ?? null);
-        writeAudit({
+        const tokens = this.oauth.issueTokens(client.client_id, pending.userId, pending.scopes, null, pending.resource ?? null);
+        this.audit.writeAudit({
             userId: pending.userId,
             action: 'oauth.token.issue',
             details: { client_id: client.client_id, scopes: pending.scopes, audience: pending.resource ?? null },
             ip: null,
         });
         return tokens;
-    },
+    }
 
     async exchangeRefreshToken(
         client: OAuthClientInformationFull,
@@ -196,13 +192,13 @@ export const trekOAuthProvider: OAuthServerProvider = {
         _scopes?: string[],
         _resource?: URL,
     ): Promise<OAuthTokens> {
-        const result = refreshTokens(refreshToken, client.client_id, client.client_secret, null);
+        const result = this.oauth.refreshTokens(refreshToken, client.client_id, client.client_secret, null);
         if (result.error) throw new Error(result.error === 'invalid_client' ? 'Invalid client credentials' : 'Refresh token is invalid or expired');
         return result.tokens!;
-    },
+    }
 
     async verifyAccessToken(token: string): Promise<AuthInfo> {
-        const info = getUserByAccessToken(token);
+        const info = this.oauth.getUserByAccessToken(token);
         if (!info) throw new Error('Invalid or expired token');
         return {
             token,
@@ -210,12 +206,12 @@ export const trekOAuthProvider: OAuthServerProvider = {
             scopes: info.scopes,
             extra: { user: info.user },
         };
-    },
+    }
 
     async revokeToken(
         client: OAuthClientInformationFull,
         request: OAuthTokenRevocationRequest,
     ): Promise<void> {
-        serviceRevokeToken(request.token, client.client_id, undefined, null);
-    },
-};
\ No newline at end of file
+        this.oauth.revokeToken(request.token, client.client_id, undefined, null);
+    }
+}
diff --git a/server/src/nest/oauth/oauth.bridge.ts b/server/src/nest/oauth/oauth.bridge.ts
index 4c2075e75..40e3759bf 100644
--- a/server/src/nest/oauth/oauth.bridge.ts
+++ b/server/src/nest/oauth/oauth.bridge.ts
@@ -5,22 +5,17 @@ import { DatabaseService } from '../database/database.service';
 import { OauthService } from './oauth.service';
 
 /**
- * Non-Nest entry point for the OAuth domain — for code running OUTSIDE the
- * Nest container: the MCP transport (src/mcp/index.ts token verification) and
- * the SDK provider adapter (src/mcp/oauthProvider.ts), which
+ * Non-Nest entry point for the OAuth domain — down to its last consumer: the
+ * MCP transport's token verification (src/mcp/index.ts), which
  * platform.routes.ts mounts on the Express app BEFORE app.init(), so
- * `app.get(OauthService)` is not available to it. Exports the legacy
- * services/oauthService names 1:1 so repointing a consumer is an
- * import-path-only diff. Inside the container, inject OauthService instead.
- * Delete this file when the SDK mount moves behind the container.
+ * `app.get(OauthService)` is not available to it. The SDK provider adapter
+ * moved behind the container (oauth-sdk.provider.ts) and dropped the other six
+ * exports. Inside the container, inject OauthService instead. Delete this file
+ * when the /mcp mount moves behind the container.
  *
  * Module-level construction is safe: `db` is the reinitialize-proof Proxy onto
- * the shared better-sqlite3 singleton. The one piece of shared state — the
- * pending authorization codes — is module-scoped in oauth.pending-codes.ts, so
- * this instance and the container singleton see the same map. That is load-
- * bearing: the consent controller writes the code through the container and
- * the SDK reads it back through here (which is why consumeAuthCode is bridged
- * and createAuthCode is not).
+ * the shared better-sqlite3 singleton, and getUserByAccessToken touches no
+ * module-scoped state beyond it.
  */
 const dbs = new DatabaseService(db);
 const oauth = new OauthService(dbs, new AddonsService(dbs), new AuditService(dbs));
@@ -28,27 +23,3 @@ const oauth = new OauthService(dbs, new AddonsService(dbs), new AuditService(dbs
 export function getUserByAccessToken(rawToken: string) {
   return oauth.getUserByAccessToken(rawToken);
 }
-
-export function createOAuthClient(...args: Parameters<OauthService['createOAuthClient']>) {
-  return oauth.createOAuthClient(...args);
-}
-
-export function consumeAuthCode(code: string) {
-  return oauth.consumeAuthCode(code);
-}
-
-export function issueTokens(...args: Parameters<OauthService['issueTokens']>) {
-  return oauth.issueTokens(...args);
-}
-
-export function refreshTokens(...args: Parameters<OauthService['refreshTokens']>) {
-  return oauth.refreshTokens(...args);
-}
-
-export function revokeToken(...args: Parameters<OauthService['revokeToken']>) {
-  return oauth.revokeToken(...args);
-}
-
-export function verifyPKCE(codeVerifier: string, codeChallenge: string): boolean {
-  return oauth.verifyPKCE(codeVerifier, codeChallenge);
-}
diff --git a/server/src/nest/oauth/oauth.module.ts b/server/src/nest/oauth/oauth.module.ts
index ddb1f1020..9dc0e1299 100644
--- a/server/src/nest/oauth/oauth.module.ts
+++ b/server/src/nest/oauth/oauth.module.ts
@@ -1,27 +1,66 @@
 import { RateLimitModule } from '../common/rate-limit.module';
 import { Module } from '@nestjs/common';
+import type { MiddlewareConsumer, NestModule } from '@nestjs/common';
+import { authorizationHandler } from '@modelcontextprotocol/sdk/server/auth/handlers/authorize';
+import { clientRegistrationHandler } from '@modelcontextprotocol/sdk/server/auth/handlers/register';
 import { OauthPublicController } from './oauth-public.controller';
 import { OauthApiController } from './oauth-api.controller';
 import { OauthService } from './oauth.service';
+import { TrekClientsStore, TrekOAuthProvider } from './oauth-sdk.provider';
 import { AuditModule } from '../audit/audit.module';
 import { AddonsModule } from '../addons/addons.module';
+import { AddonsService } from '../addons/addons.service';
+import { createMcpAddonGate } from '../addons/mcp-addon-gate';
 
 /**
  * OAuth 2.1 server (MCP). Public token/userinfo/revoke endpoints + the SPA's
- * authenticated consent/client/session management. /oauth/authorize,
- * /oauth/register and /oauth/consent are still served by the MCP SDK's own
- * router, mounted on the Express platform before app.init() — that path
- * reaches the domain through oauth.bridge.ts, which is why the pending
- * authorization codes live in a module, not on the provider.
+ * authenticated consent/client/session management, plus the SDK's own
+ * /oauth/authorize and /oauth/register Express routers, mounted here through
+ * MiddlewareConsumer over the injected TrekOAuthProvider/TrekClientsStore.
+ * forRoutes('<path>') is an Express prefix mount — the same app.use('/path')
+ * shape (and the same req.url stripping) the pre-init platform mount used, and
+ * exactly what the SDK routers are built for. The handlers are constructed once
+ * per app instance in configure(), preserving the per-app lifetime of the DCR
+ * handler's built-in rate limiter.
  *
- * Exports OauthService for AdminController, which serves the admin OAuth-session
- * panel under /api/admin. That is the one in-container consumer; everything
- * outside the container still goes through oauth.bridge.ts.
+ * The handlers bring their own body parsers; the global 100kb parsers run
+ * first and theirs no-op on the already-consumed stream. The one observable
+ * difference vs the pre-init mount: bracketed keys in a POST /oauth/authorize
+ * body now parse with qs (extended:true) rather than querystring — the SDK
+ * zod-rejects such bodies either way.
+ *
+ * Pending authorization codes live module-scoped in oauth.pending-codes.ts:
+ * the consent controller (container singleton) writes them, the SDK exchange
+ * path reads them back through the same injected singleton.
+ *
+ * Exports OauthService for AdminController (admin OAuth-session panel) and the
+ * MCP transport's token verification.
  */
 @Module({
   imports: [RateLimitModule, AuditModule, AddonsModule],
   controllers: [OauthPublicController, OauthApiController],
-  providers: [OauthService],
+  providers: [OauthService, TrekClientsStore, TrekOAuthProvider],
   exports: [OauthService],
 })
-export class OauthModule {}
+export class OauthModule implements NestModule {
+  constructor(
+    private readonly addons: AddonsService,
+    private readonly provider: TrekOAuthProvider,
+    private readonly clients: TrekClientsStore,
+  ) {}
+
+  configure(consumer: MiddlewareConsumer): void {
+    const mcpAddonGate = createMcpAddonGate(this.addons);
+
+    // SDK authorize handler: validates OAuth params, calls provider.authorize()
+    // which redirects to the SPA consent page at /oauth/consent
+    consumer
+      .apply(mcpAddonGate, authorizationHandler({ provider: this.provider }))
+      .forRoutes('oauth/authorize');
+
+    // SDK DCR handler: accepts registrations without scope (fixes issue #959 bug 2)
+    consumer
+      .apply(mcpAddonGate, clientRegistrationHandler({ clientsStore: this.clients }))
+      .forRoutes('oauth/register');
+  }
+}
diff --git a/server/src/nest/oauth/oauth.pending-codes.ts b/server/src/nest/oauth/oauth.pending-codes.ts
index 5f74374aa..19dff12b6 100644
--- a/server/src/nest/oauth/oauth.pending-codes.ts
+++ b/server/src/nest/oauth/oauth.pending-codes.ts
@@ -1,13 +1,14 @@
 /**
  * The short-lived authorization-code store.
  *
- * Module-scoped + import-time interval on purpose (legacy parity, shared
- * between bridge and container instances — atlas-geo interval precedent).
- * This is not a stylistic choice: the SDK-mounted /oauth/authorize path reads
- * a code through oauth.bridge (mcp/oauthProvider.ts) that the Nest consent
- * controller wrote through the container singleton. Two instances would mean
- * two maps, and the authorization-code flow would fail *silently* — the SDK
- * only ever answers "Authorization grant is invalid."
+ * Module-scoped + import-time interval on purpose (legacy parity — atlas-geo
+ * interval precedent). This is not a stylistic choice: the consent controller
+ * writes a code through the container OauthService and the SDK exchange path
+ * (oauth-sdk.provider.ts) reads it back — through the same injected singleton
+ * in production, but the integration harness and any second OauthService
+ * instance must keep seeing the same map. Two maps would make the
+ * authorization-code flow fail *silently* — the SDK only ever answers
+ * "Authorization grant is invalid."
  *
  * No DB persistence: codes live two minutes and a restart invalidating them
  * is the correct behaviour.
diff --git a/server/src/nest/oauth/oauth.service.ts b/server/src/nest/oauth/oauth.service.ts
index 064bdda8d..14de55807 100644
--- a/server/src/nest/oauth/oauth.service.ts
+++ b/server/src/nest/oauth/oauth.service.ts
@@ -349,6 +349,22 @@ export class OauthService {
   // Token verification (used by MCP handler on every request)
   // -------------------------------------------------------------------------
 
+  /** SDK clients-store read: the exact row shape the MCP SDK adapter
+   *  (oauth-sdk.provider.ts) maps to OAuthClientInformationFull. */
+  getSdkClient(clientId: string): {
+    client_id: string;
+    name: string;
+    redirect_uris: string;
+    allowed_scopes: string;
+    is_public: number;
+    created_via: string;
+  } | undefined {
+    return this.db.get(
+      'SELECT client_id, name, redirect_uris, allowed_scopes, is_public, created_via FROM oauth_clients WHERE client_id = ?',
+      clientId,
+    );
+  }
+
   getUserByAccessToken(rawToken: string): OAuthTokenInfo | null {
     const hash = hashToken(rawToken);
     const row = this.db.get<OAuthTokenRow & { username: string; email: string; role: string }>(`
diff --git a/server/src/nest/platform/platform.routes.ts b/server/src/nest/platform/platform.routes.ts
index 51807e4ec..efb8e1799 100644
--- a/server/src/nest/platform/platform.routes.ts
+++ b/server/src/nest/platform/platform.routes.ts
@@ -6,11 +6,6 @@ import { readEnv } from '../../app-config';
 import { verifyJwtAndLoadUser } from '../auth/jwt-verify';
 import { db } from '../../db/database';
 import { mcpHandler } from '../../mcp';
-import { trekOAuthProvider, trekClientsStore } from '../../mcp/oauthProvider';
-import { isAddonEnabled } from '../addons/addons.bridge';
-import { ADDON_IDS } from '../../addons';
-import { authorizationHandler } from '@modelcontextprotocol/sdk/server/auth/handlers/authorize';
-import { clientRegistrationHandler } from '@modelcontextprotocol/sdk/server/auth/handlers/register';
 
 // Platform / transport routes extracted verbatim from createApp() (app.ts) so they can be
 // mounted on either the legacy Express app or the NestJS Express instance (strangler A6/A8).
@@ -100,27 +95,14 @@ export function applyPlatformUploads(app: express.Application): void {
 }
 
 /**
- * The OAuth SDK + /mcp transport mounts still living on the pre-init Express
- * layer. The rest of the former transport surface is behind the container now:
- * /api/health (FeaturesController), OAuth discovery (DiscoveryController + the
- * McpMetadataMiddleware bootstrap applies pre-init), and the /oauth/consent
- * COOP override (ConsentCoopMiddleware via PlatformModule.configure).
+ * The /mcp transport mounts — the last pre-init platform routes. Everything
+ * else that used to live here is behind the container now: /api/health
+ * (FeaturesController), OAuth discovery (DiscoveryController + the metadata
+ * middleware bootstrap applies pre-init), /oauth/authorize + /oauth/register
+ * (OauthModule.configure over the injected SDK adapters), and the
+ * /oauth/consent COOP override (ConsentCoopMiddleware).
  */
 export function applyPlatformTransport(app: express.Application): void {
-  // OAuth 2.1 — public endpoints
-  // Gate: 404 when MCP addon is disabled (M2 — prevents feature fingerprinting)
-  const mcpAddonGate = (_req: Request, res: Response, next: NextFunction) => {
-    if (!isAddonEnabled(ADDON_IDS.MCP)) return res.status(404).end();
-    next();
-  };
-
-  // SDK authorize handler: validates OAuth params, calls provider.authorize() which redirects
-  // to the SPA consent page at /oauth/consent
-  app.use('/oauth/authorize', mcpAddonGate, authorizationHandler({ provider: trekOAuthProvider }));
-
-  // SDK DCR handler: accepts registrations without scope (fixes issue #959 bug 2)
-  app.use('/oauth/register', mcpAddonGate, clientRegistrationHandler({ clientsStore: trekClientsStore }));
-
   // MCP endpoint
   app.post('/mcp', mcpHandler);
   app.get('/mcp', mcpHandler);
diff --git a/server/tests/integration/oauth-authorize.test.ts b/server/tests/integration/oauth-authorize.test.ts
new file mode 100644
index 000000000..3217e8f5f
--- /dev/null
+++ b/server/tests/integration/oauth-authorize.test.ts
@@ -0,0 +1,289 @@
+/**
+ * HTTP-level tests for GET /oauth/authorize — the MCP SDK authorizationHandler
+ * wrapping TREK's OAuthServerProvider. Written as byte-level parity oracles for
+ * the MCP/OAuth mount migration: they must pass identically while the handler
+ * is mounted pre-init AND after it moves behind the Nest container.
+ *
+ * This was the one platform surface with no HTTP coverage at all —
+ * trekOAuthProvider.authorize and trekClientsStore.getClient run for the first
+ * time under test here.
+ */
+import { describe, it, expect, vi, beforeAll, beforeEach, afterAll } from 'vitest';
+import request from 'supertest';
+import type { Application } from 'express';
+import type { INestApplication } from '@nestjs/common';
+import crypto from 'crypto';
+
+const { testDb, dbMock } = vi.hoisted(() => {
+    const Database = require('better-sqlite3');
+    const db = new Database(':memory:');
+    db.exec('PRAGMA journal_mode = WAL');
+    db.exec('PRAGMA foreign_keys = ON');
+    db.exec('PRAGMA busy_timeout = 5000');
+    const mock = {
+        db,
+        closeDb: () => {},
+        reinitialize: () => {},
+        getPlaceWithTags: () => null,
+        canAccessTrip: () => undefined,
+        isOwner: () => false,
+    };
+    return { testDb: db, dbMock: mock };
+});
+
+vi.mock('../../src/db/database', () => dbMock);
+vi.mock('../../src/config', () => ({
+    JWT_SECRET: 'test-jwt-secret-for-trek-testing-only',
+    ENCRYPTION_KEY: 'a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6a7b8c9d0e1f2a3b4c5d6a7b8c9d0e1f2',
+    updateJwtSecret: () => {},
+    SESSION_DURATION: '24h',
+    SESSION_DURATION_MS: 86400000,
+    SESSION_DURATION_SECONDS: 86400,
+    DEFAULT_LANGUAGE: 'en',
+}));
+
+vi.mock('../../src/app-config', async (importOriginal) => {
+    const actual = await importOriginal<typeof import('../../src/app-config')>();
+    return { ...actual, getMcpSafeUrl: () => 'https://trek.example.com' };
+});
+
+vi.mock('../../src/websocket', () => ({ broadcast: vi.fn(), broadcastToUser: vi.fn() }));
+vi.mock('../../src/mcp/sessionManager', () => ({ revokeUserSessions: vi.fn(), revokeUserSessionsForClient: vi.fn(), sessions: new Map() }));
+
+import { buildApp } from '../../src/bootstrap';
+import { createTables } from '../../src/db/schema';
+import { runMigrations } from '../../src/db/migrations';
+import { resetTestDb, resetRateLimits } from '../helpers/test-db';
+import { createUser } from '../helpers/factories';
+import { OauthService } from '../../src/nest/oauth/oauth.service';
+import { DatabaseService } from '../../src/nest/database/database.service';
+import { AddonsService } from '../../src/nest/addons/addons.service';
+import { AuditService } from '../../src/nest/audit/audit.service';
+
+// The consent controller writes pending codes through the container instance;
+// the SDK-mounted authorize path reads them back. The map is module-scoped in
+// oauth.pending-codes.ts, so a hand-built service instance shares it — the
+// same single-instance property the full auth-code loop below proves end-to-end.
+const oauthDbs = new DatabaseService(testDb);
+const containerSideOauth = new OauthService(oauthDbs, new AddonsService(oauthDbs), new AuditService(oauthDbs));
+
+let nestApp: INestApplication;
+let app: Application;
+
+function makePkce() {
+    const verifier = crypto.randomBytes(32).toString('base64url');
+    const challenge = crypto.createHash('sha256').update(verifier).digest('base64url');
+    return { verifier, challenge };
+}
+
+function setMcpEnabled(enabled: boolean) {
+    testDb.prepare(
+        "INSERT OR REPLACE INTO addons (id, name, description, type, icon, enabled, sort_order) VALUES ('mcp', 'MCP', 'AI assistant integration', 'integration', 'Terminal', ?, 12)"
+    ).run(enabled ? 1 : 0);
+}
+
+/** DCR-register a public client and return its client_id. */
+async function registerClient(redirectUri = 'https://client.example.com/cb', scope = 'trips:read'): Promise<string> {
+    const res = await request(app)
+        .post('/oauth/register')
+        .set('Content-Type', 'application/json')
+        .send({ redirect_uris: [redirectUri], token_endpoint_auth_method: 'none', scope });
+    expect(res.status).toBe(201);
+    return res.body.client_id as string;
+}
+
+beforeAll(async () => {
+    createTables(testDb);
+    runMigrations(testDb);
+    nestApp = await buildApp();
+    app = nestApp.getHttpAdapter().getInstance();
+});
+
+beforeEach(() => {
+    resetTestDb(testDb);
+    resetRateLimits(nestApp);
+    setMcpEnabled(true);
+});
+
+afterAll(async () => {
+    await nestApp.close();
+    testDb.close();
+});
+
+describe('GET /oauth/authorize — SDK authorizationHandler over trekOAuthProvider', () => {
+    it('AUTHZ-001 — happy path 302-redirects to the SPA consent page with the exact forwarded params', async () => {
+        const clientId = await registerClient();
+        const { challenge } = makePkce();
+
+        const res = await request(app).get('/oauth/authorize').query({
+            response_type: 'code',
+            client_id: clientId,
+            redirect_uri: 'https://client.example.com/cb',
+            scope: 'trips:read',
+            state: 'st4te',
+            code_challenge: challenge,
+            code_challenge_method: 'S256',
+            resource: 'https://trek.example.com/mcp',
+        });
+
+        expect(res.status).toBe(302);
+        const expected = new URLSearchParams({
+            client_id: clientId,
+            redirect_uri: 'https://client.example.com/cb',
+            scope: 'trips:read',
+            code_challenge: challenge,
+            code_challenge_method: 'S256',
+            state: 'st4te',
+            resource: 'https://trek.example.com/mcp',
+        });
+        expect(res.headers.location).toBe(`https://trek.example.com/oauth/consent?${expected.toString()}`);
+    });
+
+    it('AUTHZ-002 — omitted resource defaults to the MCP endpoint and still reaches consent', async () => {
+        const clientId = await registerClient();
+        const { challenge } = makePkce();
+
+        const res = await request(app).get('/oauth/authorize').query({
+            response_type: 'code',
+            client_id: clientId,
+            redirect_uri: 'https://client.example.com/cb',
+            scope: 'trips:read',
+            code_challenge: challenge,
+            code_challenge_method: 'S256',
+        });
+
+        expect(res.status).toBe(302);
+        const loc = new URL(res.headers.location);
+        expect(`${loc.origin}${loc.pathname}`).toBe('https://trek.example.com/oauth/consent');
+        expect(loc.searchParams.get('client_id')).toBe(clientId);
+        // No resource param was sent, so none is forwarded.
+        expect(loc.searchParams.get('resource')).toBeNull();
+        expect(loc.searchParams.get('state')).toBeNull();
+    });
+
+    it('AUTHZ-003 — wrong resource 302-redirects back to the client with invalid_target', async () => {
+        const clientId = await registerClient();
+        const { challenge } = makePkce();
+
+        const res = await request(app).get('/oauth/authorize').query({
+            response_type: 'code',
+            client_id: clientId,
+            redirect_uri: 'https://client.example.com/cb',
+            scope: 'trips:read',
+            state: 'xyz',
+            code_challenge: challenge,
+            code_challenge_method: 'S256',
+            resource: 'https://evil.example.com/other',
+        });
+
+        expect(res.status).toBe(302);
+        const loc = new URL(res.headers.location);
+        expect(`${loc.origin}${loc.pathname}`).toBe('https://client.example.com/cb');
+        expect(loc.searchParams.get('error')).toBe('invalid_target');
+        expect(loc.searchParams.get('error_description')).toBe('Requested resource must be the TREK MCP endpoint');
+        expect(loc.searchParams.get('state')).toBe('xyz');
+    });
+
+    it('AUTHZ-004 — unknown client_id is a 400 invalid_client, no redirect', async () => {
+        const { challenge } = makePkce();
+        const res = await request(app).get('/oauth/authorize').query({
+            response_type: 'code',
+            client_id: 'does-not-exist',
+            redirect_uri: 'https://client.example.com/cb',
+            scope: 'trips:read',
+            code_challenge: challenge,
+            code_challenge_method: 'S256',
+        });
+        expect(res.status).toBe(400);
+        expect(res.body.error).toBe('invalid_client');
+    });
+
+    it('AUTHZ-005 — unregistered redirect_uri is a 400 invalid_request, no redirect', async () => {
+        const clientId = await registerClient();
+        const { challenge } = makePkce();
+        const res = await request(app).get('/oauth/authorize').query({
+            response_type: 'code',
+            client_id: clientId,
+            redirect_uri: 'https://attacker.example.com/cb',
+            scope: 'trips:read',
+            code_challenge: challenge,
+            code_challenge_method: 'S256',
+        });
+        expect(res.status).toBe(400);
+        expect(res.body.error).toBe('invalid_request');
+    });
+
+    it('AUTHZ-006 — missing code_challenge redirects back to the client with invalid_request', async () => {
+        const clientId = await registerClient();
+        const res = await request(app).get('/oauth/authorize').query({
+            response_type: 'code',
+            client_id: clientId,
+            redirect_uri: 'https://client.example.com/cb',
+            scope: 'trips:read',
+        });
+        expect(res.status).toBe(302);
+        const loc = new URL(res.headers.location);
+        expect(`${loc.origin}${loc.pathname}`).toBe('https://client.example.com/cb');
+        expect(loc.searchParams.get('error')).toBe('invalid_request');
+    });
+
+    it('AUTHZ-007 — MCP addon off: authorize and register both 404 with empty bodies', async () => {
+        setMcpEnabled(false);
+        const authz = await request(app).get('/oauth/authorize').query({ client_id: 'x' });
+        expect(authz.status).toBe(404);
+        expect(authz.text).toBe('');
+
+        const reg = await request(app)
+            .post('/oauth/register')
+            .set('Content-Type', 'application/json')
+            .send({ redirect_uris: ['https://client.example.com/cb'], token_endpoint_auth_method: 'none' });
+        expect(reg.status).toBe(404);
+        expect(reg.text).toBe('');
+    });
+
+    it('AUTHZ-008 — full loop: register → authorize → consent-written code → token exchange', async () => {
+        const { user } = createUser(testDb);
+        const clientId = await registerClient();
+        const { verifier, challenge } = makePkce();
+
+        // 1. authorize forwards to consent
+        const authz = await request(app).get('/oauth/authorize').query({
+            response_type: 'code',
+            client_id: clientId,
+            redirect_uri: 'https://client.example.com/cb',
+            scope: 'trips:read',
+            code_challenge: challenge,
+            code_challenge_method: 'S256',
+            resource: 'https://trek.example.com/mcp',
+        });
+        expect(authz.status).toBe(302);
+
+        // 2. the consent controller writes the code through the container
+        //    singleton; the module-scoped pending-code map is what lets the
+        //    SDK-side exchange see it.
+        const code = containerSideOauth.createAuthCode({
+            clientId,
+            userId: user.id,
+            redirectUri: 'https://client.example.com/cb',
+            scopes: ['trips:read'],
+            resource: 'https://trek.example.com/mcp',
+            codeChallenge: challenge,
+            codeChallengeMethod: 'S256',
+        });
+        expect(code).toBeTruthy();
+
+        // 3. token exchange through the public token endpoint
+        const token = await request(app).post('/oauth/token').send({
+            grant_type: 'authorization_code',
+            client_id: clientId,
+            code,
+            redirect_uri: 'https://client.example.com/cb',
+            code_verifier: verifier,
+            resource: 'https://trek.example.com/mcp',
+        });
+        expect(token.status).toBe(200);
+        expect(token.body.access_token).toMatch(/^trekoa_/);
+        expect(token.body.token_type).toBe('Bearer');
+        expect(token.body.scope).toBe('trips:read');
+    });
+});
diff --git a/server/tests/integration/oauth.test.ts b/server/tests/integration/oauth.test.ts
index caf77224c..d04448c01 100644
--- a/server/tests/integration/oauth.test.ts
+++ b/server/tests/integration/oauth.test.ts
@@ -58,7 +58,6 @@ import { runMigrations } from '../../src/db/migrations';
 import { resetTestDb, resetRateLimits } from '../helpers/test-db';
 import { createUser } from '../helpers/factories';
 import { authCookie } from '../helpers/auth';
-import { createOAuthClient, getUserByAccessToken } from '../../src/nest/oauth/oauth.bridge';
 import { ALL_SCOPES } from '../../src/mcp/scopes';
 import { OauthService } from '../../src/nest/oauth/oauth.service';
 import { DatabaseService } from '../../src/nest/database/database.service';
@@ -66,14 +65,15 @@ import { AddonsService } from '../../src/nest/addons/addons.service';
 import { AuditService } from '../../src/nest/audit/audit.service';
 
 // In production the consent controller writes pending codes through the
-// container instance and the SDK-mounted routes read them back through the
-// bridge. createAuthCode is not bridged (only the read side is), so the tests
-// write codes the same way the consent controller does: through a service
-// instance. The pending-code map is module-scoped in oauth.pending-codes.ts,
-// so the routes under test see every code written here.
+// container instance and the SDK routes read them back through the same
+// injected singleton. These tests write codes the way the consent controller
+// does: through a service instance. The pending-code map is module-scoped in
+// oauth.pending-codes.ts, so the routes under test see every code written here.
 const oauthDbs = new DatabaseService(testDb);
 const containerSideOauth = new OauthService(oauthDbs, new AddonsService(oauthDbs), new AuditService(oauthDbs));
 const createAuthCode = containerSideOauth.createAuthCode.bind(containerSideOauth);
+const createOAuthClient = containerSideOauth.createOAuthClient.bind(containerSideOauth);
+const getUserByAccessToken = containerSideOauth.getUserByAccessToken.bind(containerSideOauth);
 
 let nestApp: INestApplication;
 let app: Application;
diff --git a/server/tests/unit/nest/mcp-addon-gate.test.ts b/server/tests/unit/nest/mcp-addon-gate.test.ts
new file mode 100644
index 000000000..8a9ae06aa
--- /dev/null
+++ b/server/tests/unit/nest/mcp-addon-gate.test.ts
@@ -0,0 +1,41 @@
+import { describe, it, expect, vi } from 'vitest';
+import { createMcpAddonGate } from '../../../src/nest/addons/mcp-addon-gate';
+import { ADDON_IDS } from '../../../src/addons';
+import type { AddonsService } from '../../../src/nest/addons/addons.service';
+
+function gate(enabled: boolean) {
+  const addons = { isAddonEnabled: vi.fn(() => enabled) };
+  return { addons, mw: createMcpAddonGate(addons as unknown as AddonsService) };
+}
+
+function makeRes() {
+  const res = {
+    statusCode: 200,
+    ended: false,
+    status: vi.fn(function (this: typeof res, c: number) { this.statusCode = c; return this; }),
+    end: vi.fn(function (this: typeof res) { this.ended = true; return this; }),
+  };
+  return res;
+}
+
+describe('createMcpAddonGate', () => {
+  it('GATE-001: 404s with an empty body when the MCP addon is off', () => {
+    const { addons, mw } = gate(false);
+    const res = makeRes();
+    const next = vi.fn();
+    mw({} as never, res as never, next);
+    expect(addons.isAddonEnabled).toHaveBeenCalledWith(ADDON_IDS.MCP);
+    expect(res.statusCode).toBe(404);
+    expect(res.ended).toBe(true);
+    expect(next).not.toHaveBeenCalled();
+  });
+
+  it('GATE-002: continues when the addon is on', () => {
+    const { mw } = gate(true);
+    const res = makeRes();
+    const next = vi.fn();
+    mw({} as never, res as never, next);
+    expect(res.statusCode).toBe(200);
+    expect(next).toHaveBeenCalled();
+  });
+});
diff --git a/server/tests/unit/nest/oauth-sdk.provider.test.ts b/server/tests/unit/nest/oauth-sdk.provider.test.ts
new file mode 100644
index 000000000..c113e8340
--- /dev/null
+++ b/server/tests/unit/nest/oauth-sdk.provider.test.ts
@@ -0,0 +1,461 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+
+const h = vi.hoisted(() => ({
+  getMcpSafeUrl: vi.fn(() => 'https://trek.example.test'),
+}));
+
+vi.mock('../../../src/app-config', async (importOriginal) => {
+  const actual = await importOriginal<typeof import('../../../src/app-config')>();
+  return { ...actual, getMcpSafeUrl: h.getMcpSafeUrl };
+});
+
+const sdk = vi.hoisted(() => ({
+  authorizeHandler: vi.fn(),
+  registerHandler: vi.fn(),
+}));
+vi.mock('@modelcontextprotocol/sdk/server/auth/handlers/authorize', () => ({
+  authorizationHandler: vi.fn(() => sdk.authorizeHandler),
+}));
+vi.mock('@modelcontextprotocol/sdk/server/auth/handlers/register', () => ({
+  clientRegistrationHandler: vi.fn(() => sdk.registerHandler),
+}));
+
+import { authorizationHandler } from '@modelcontextprotocol/sdk/server/auth/handlers/authorize';
+import { clientRegistrationHandler } from '@modelcontextprotocol/sdk/server/auth/handlers/register';
+import { InvalidClientMetadataError, ServerError } from '@modelcontextprotocol/sdk/server/auth/errors';
+import { TrekClientsStore, TrekOAuthProvider } from '../../../src/nest/oauth/oauth-sdk.provider';
+import { OauthModule } from '../../../src/nest/oauth/oauth.module';
+import type { AddonsService } from '../../../src/nest/addons/addons.service';
+import { ALL_SCOPES } from '../../../src/mcp/scopes';
+import type { OauthService } from '../../../src/nest/oauth/oauth.service';
+import type { AuditService } from '../../../src/nest/audit/audit.service';
+import type { OAuthClientInformationFull } from '@modelcontextprotocol/sdk/shared/auth';
+
+function makeOauth(overrides: Partial<Record<keyof OauthService, unknown>> = {}) {
+  return {
+    getSdkClient: vi.fn(),
+    createOAuthClient: vi.fn(() => ({ client: baseClientRecord() })),
+    consumeAuthCode: vi.fn(),
+    issueTokens: vi.fn(() => tokens()),
+    refreshTokens: vi.fn(() => ({ tokens: tokens() })),
+    getUserByAccessToken: vi.fn(),
+    revokeToken: vi.fn(),
+    verifyPKCE: vi.fn(() => true),
+    ...overrides,
+  } as unknown as OauthService;
+}
+
+function makeAudit() {
+  return { writeAudit: vi.fn() } as unknown as AuditService;
+}
+
+function baseClientRecord() {
+  return {
+    client_id: 'cid-1',
+    name: 'Registered',
+    redirect_uris: ['https://client.example.com/cb'],
+    allowed_scopes: ['trips:read'],
+  } as Record<string, unknown>;
+}
+
+function tokens() {
+  return { access_token: 'trekoa_x', refresh_token: 'trekrt_x', token_type: 'Bearer' as const, expires_in: 3600, scope: 'trips:read' };
+}
+
+function clientInfo(over: Partial<OAuthClientInformationFull> = {}): OAuthClientInformationFull {
+  return {
+    client_id: 'cid-1',
+    redirect_uris: ['https://client.example.com/cb'],
+    ...over,
+  } as OAuthClientInformationFull;
+}
+
+function pending(over: Partial<Record<string, unknown>> = {}) {
+  return {
+    clientId: 'cid-1',
+    userId: 7,
+    redirectUri: 'https://client.example.com/cb',
+    scopes: ['trips:read'],
+    resource: 'https://trek.example.test/mcp',
+    codeChallenge: 'chal',
+    codeChallengeMethod: 'S256' as const,
+    expiresAt: Date.now() + 60_000,
+    ...over,
+  };
+}
+
+beforeEach(() => {
+  vi.clearAllMocks();
+  h.getMcpSafeUrl.mockReturnValue('https://trek.example.test');
+});
+
+// ─────────────────────────────────────────────────────────────────────────────
+// TrekClientsStore
+// ─────────────────────────────────────────────────────────────────────────────
+
+describe('TrekClientsStore.getClient', () => {
+  it('SDKP-001: maps a public client row to SDK client info', async () => {
+    const oauth = makeOauth({
+      getSdkClient: vi.fn(() => ({
+        client_id: 'cid-1', name: 'App', redirect_uris: '["https://a.example.com/cb"]',
+        allowed_scopes: '["trips:read","trips:write"]', is_public: 1, created_via: 'dcr',
+      })),
+    });
+    const info = await new TrekClientsStore(oauth).getClient('cid-1');
+    expect(info).toEqual({
+      client_id: 'cid-1',
+      client_name: 'App',
+      redirect_uris: ['https://a.example.com/cb'],
+      scope: 'trips:read trips:write',
+      token_endpoint_auth_method: 'none',
+      grant_types: ['authorization_code', 'refresh_token'],
+      response_types: ['code'],
+    });
+  });
+
+  it('SDKP-002: a confidential client maps to client_secret_post', async () => {
+    const oauth = makeOauth({
+      getSdkClient: vi.fn(() => ({
+        client_id: 'cid-2', name: 'Secret', redirect_uris: '[]', allowed_scopes: '["trips:read"]',
+        is_public: 0, created_via: 'ui',
+      })),
+    });
+    const info = await new TrekClientsStore(oauth).getClient('cid-2');
+    expect(info!.token_endpoint_auth_method).toBe('client_secret_post');
+  });
+
+  it('SDKP-003: unknown client resolves undefined', async () => {
+    const store = new TrekClientsStore(makeOauth({ getSdkClient: vi.fn(() => undefined) }));
+    await expect(store.getClient('nope')).resolves.toBeUndefined();
+  });
+});
+
+describe('TrekClientsStore.registerClient', () => {
+  const store = () => new TrekClientsStore(makeOauth());
+
+  it('SDKP-010: rejects a malformed redirect URI', async () => {
+    await expect(store().registerClient({ redirect_uris: ['not a url'] } as never))
+      .rejects.toThrowError(new InvalidClientMetadataError('Invalid redirect URI: not a url'));
+  });
+
+  it('SDKP-011: rejects dangerous schemes', async () => {
+    await expect(store().registerClient({ redirect_uris: ['javascript:alert(1)'] } as never))
+      .rejects.toThrowError(new InvalidClientMetadataError('Dangerous redirect URI scheme: javascript:alert(1)'));
+  });
+
+  it('SDKP-012: rejects plain-http non-loopback and dot-less custom schemes', async () => {
+    const msg = 'redirect_uris must be HTTPS, loopback HTTP, or a private custom scheme';
+    await expect(store().registerClient({ redirect_uris: ['http://evil.example.com/cb'] } as never))
+      .rejects.toThrowError(new InvalidClientMetadataError(msg));
+    await expect(store().registerClient({ redirect_uris: ['myapp://cb'] } as never))
+      .rejects.toThrowError(new InvalidClientMetadataError(msg));
+  });
+
+  it('SDKP-013: accepts https, loopback http, and reverse-DNS custom schemes', async () => {
+    for (const uri of [
+      'https://a.example.com/cb',
+      'http://localhost:8080/cb',
+      'http://127.0.0.1/cb',
+      'http://[::1]/cb',
+      'com.example.app:/oauth',
+    ]) {
+      const oauth = makeOauth();
+      await new TrekClientsStore(oauth).registerClient({
+        redirect_uris: [uri], token_endpoint_auth_method: 'none', scope: 'trips:read',
+      } as never);
+      expect(oauth.createOAuthClient).toHaveBeenCalled();
+    }
+  });
+
+  it('SDKP-014: blank/missing client_name defaults to MCP Client; long names are clipped', async () => {
+    const oauth = makeOauth();
+    const s = new TrekClientsStore(oauth);
+    await s.registerClient({ redirect_uris: ['https://a.example.com/cb'], scope: 'trips:read' } as never);
+    expect(vi.mocked(oauth.createOAuthClient).mock.calls[0][1]).toBe('MCP Client');
+
+    await s.registerClient({
+      redirect_uris: ['https://a.example.com/cb'], scope: 'trips:read', client_name: `  ${'x'.repeat(150)}  `,
+    } as never);
+    expect(vi.mocked(oauth.createOAuthClient).mock.calls[1][1]).toBe('x'.repeat(100));
+  });
+
+  it('SDKP-015: absent scope defaults to every scope (consent still narrows later)', async () => {
+    const oauth = makeOauth();
+    await new TrekClientsStore(oauth).registerClient({
+      redirect_uris: ['https://a.example.com/cb'], token_endpoint_auth_method: 'none',
+    } as never);
+    expect(vi.mocked(oauth.createOAuthClient).mock.calls[0][3]).toEqual(ALL_SCOPES);
+  });
+
+  it('SDKP-016: unknown scopes are filtered; nothing valid left is an error', async () => {
+    const oauth = makeOauth();
+    await new TrekClientsStore(oauth).registerClient({
+      redirect_uris: ['https://a.example.com/cb'], scope: 'trips:read bogus:scope',
+    } as never);
+    expect(vi.mocked(oauth.createOAuthClient).mock.calls[0][3]).toEqual(['trips:read']);
+
+    await expect(new TrekClientsStore(makeOauth()).registerClient({
+      redirect_uris: ['https://a.example.com/cb'], scope: 'bogus:scope',
+    } as never)).rejects.toThrowError(new InvalidClientMetadataError('No valid scopes requested'));
+  });
+
+  it('SDKP-017: a service-side rejection surfaces as InvalidClientMetadataError', async () => {
+    const oauth = makeOauth({ createOAuthClient: vi.fn(() => ({ error: 'Maximum 10 redirect URIs per client', status: 400 })) });
+    await expect(new TrekClientsStore(oauth).registerClient({
+      redirect_uris: ['https://a.example.com/cb'], scope: 'trips:read',
+    } as never)).rejects.toThrowError(new InvalidClientMetadataError('Maximum 10 redirect URIs per client'));
+  });
+
+  it('SDKP-018: response shape — public client has no secret, confidential carries a never-expiring one', async () => {
+    const pub = await new TrekClientsStore(makeOauth()).registerClient({
+      redirect_uris: ['https://a.example.com/cb'], token_endpoint_auth_method: 'none', scope: 'trips:read',
+    } as never);
+    expect(pub.token_endpoint_auth_method).toBe('none');
+    expect(pub.client_secret).toBeUndefined();
+
+    const oauth = makeOauth({
+      createOAuthClient: vi.fn(() => ({ client: { ...baseClientRecord(), client_secret: 'sec-1' } })),
+    });
+    const conf = await new TrekClientsStore(oauth).registerClient({
+      redirect_uris: ['https://a.example.com/cb'], scope: 'trips:read',
+    } as never);
+    expect(conf.token_endpoint_auth_method).toBe('client_secret_post');
+    expect(conf.client_secret).toBe('sec-1');
+    expect(conf.client_secret_expires_at).toBe(0);
+  });
+});
+
+// ─────────────────────────────────────────────────────────────────────────────
+// TrekOAuthProvider
+// ─────────────────────────────────────────────────────────────────────────────
+
+function makeProvider(oauth = makeOauth(), audit = makeAudit()) {
+  const clients = new TrekClientsStore(oauth);
+  return { provider: new TrekOAuthProvider(clients, oauth, audit), clients, oauth, audit };
+}
+
+function makeRes() {
+  return { redirect: vi.fn() };
+}
+
+describe('TrekOAuthProvider basics', () => {
+  it('SDKP-020: exposes the injected clients store and skips local PKCE', () => {
+    const { provider, clients } = makeProvider();
+    expect(provider.clientsStore).toBe(clients);
+    expect(provider.skipLocalPkceValidation).toBe(true);
+  });
+
+  it('SDKP-021: challengeForAuthorizationCode is unreachable by design', async () => {
+    const { provider } = makeProvider();
+    await expect(provider.challengeForAuthorizationCode(clientInfo(), 'code'))
+      .rejects.toThrowError(new ServerError('PKCE validation is handled by the provider directly'));
+  });
+});
+
+describe('TrekOAuthProvider.authorize', () => {
+  it('SDKP-030: forwards the exact params to the SPA consent page', async () => {
+    const { provider } = makeProvider();
+    const res = makeRes();
+    await provider.authorize(clientInfo(), {
+      redirectUri: 'https://client.example.com/cb',
+      scopes: ['trips:read', 'trips:write'],
+      codeChallenge: 'chal',
+      state: 'st',
+      resource: new URL('https://trek.example.test/mcp'),
+    } as never, res as never);
+    const qs = new URLSearchParams({
+      client_id: 'cid-1',
+      redirect_uri: 'https://client.example.com/cb',
+      scope: 'trips:read trips:write',
+      code_challenge: 'chal',
+      code_challenge_method: 'S256',
+      state: 'st',
+      resource: 'https://trek.example.test/mcp',
+    });
+    expect(res.redirect).toHaveBeenCalledWith(302, `https://trek.example.test/oauth/consent?${qs.toString()}`);
+  });
+
+  it('SDKP-031: omits state/resource params when the request carried none', async () => {
+    const { provider } = makeProvider();
+    const res = makeRes();
+    await provider.authorize(clientInfo(), {
+      redirectUri: 'https://client.example.com/cb',
+      scopes: ['trips:read'],
+      codeChallenge: 'chal',
+    } as never, res as never);
+    const target = vi.mocked(res.redirect).mock.calls[0][1] as string;
+    const url = new URL(target);
+    expect(url.searchParams.get('state')).toBeNull();
+    expect(url.searchParams.get('resource')).toBeNull();
+  });
+
+  it('SDKP-032: a foreign resource bounces back to the client with invalid_target (+state)', async () => {
+    const { provider } = makeProvider();
+    const res = makeRes();
+    await provider.authorize(clientInfo(), {
+      redirectUri: 'https://client.example.com/cb',
+      scopes: ['trips:read'],
+      codeChallenge: 'chal',
+      state: 'keep-me',
+      resource: new URL('https://other.example.com/api'),
+    } as never, res as never);
+    const target = new URL(vi.mocked(res.redirect).mock.calls[0][1] as string);
+    expect(`${target.origin}${target.pathname}`).toBe('https://client.example.com/cb');
+    expect(target.searchParams.get('error')).toBe('invalid_target');
+    expect(target.searchParams.get('error_description')).toBe('Requested resource must be the TREK MCP endpoint');
+    expect(target.searchParams.get('state')).toBe('keep-me');
+  });
+
+  it('SDKP-033: the invalid_target bounce omits state when there was none', async () => {
+    const { provider } = makeProvider();
+    const res = makeRes();
+    await provider.authorize(clientInfo(), {
+      redirectUri: 'https://client.example.com/cb',
+      scopes: ['trips:read'],
+      codeChallenge: 'chal',
+      resource: new URL('https://other.example.com/api'),
+    } as never, res as never);
+    const target = new URL(vi.mocked(res.redirect).mock.calls[0][1] as string);
+    expect(target.searchParams.get('state')).toBeNull();
+  });
+});
+
+describe('TrekOAuthProvider.exchangeAuthorizationCode', () => {
+  const invalid = 'Authorization grant is invalid.';
+
+  it('SDKP-040: unknown/expired code throws the uniform grant error', async () => {
+    const { provider } = makeProvider(makeOauth({ consumeAuthCode: vi.fn(() => null) }));
+    await expect(provider.exchangeAuthorizationCode(clientInfo(), 'code')).rejects.toThrow(invalid);
+  });
+
+  it('SDKP-041: a code minted for another client throws the same error', async () => {
+    const { provider } = makeProvider(makeOauth({ consumeAuthCode: vi.fn(() => pending({ clientId: 'someone-else' })) }));
+    await expect(provider.exchangeAuthorizationCode(clientInfo(), 'code')).rejects.toThrow(invalid);
+  });
+
+  it('SDKP-042: redirect_uri mismatch throws the same error', async () => {
+    const { provider } = makeProvider(makeOauth({ consumeAuthCode: vi.fn(() => pending()) }));
+    await expect(provider.exchangeAuthorizationCode(clientInfo(), 'code', undefined, 'https://wrong.example.com/cb'))
+      .rejects.toThrow(invalid);
+  });
+
+  it('SDKP-043: resource mismatch throws the same error', async () => {
+    const { provider } = makeProvider(makeOauth({ consumeAuthCode: vi.fn(() => pending()) }));
+    await expect(provider.exchangeAuthorizationCode(
+      clientInfo(), 'code', undefined, 'https://client.example.com/cb', new URL('https://other.example.com/'),
+    )).rejects.toThrow(invalid);
+  });
+
+  it('SDKP-044: failed PKCE throws the same error', async () => {
+    const oauth = makeOauth({ consumeAuthCode: vi.fn(() => pending()), verifyPKCE: vi.fn(() => false) });
+    const { provider } = makeProvider(oauth);
+    await expect(provider.exchangeAuthorizationCode(clientInfo(), 'code', 'bad-verifier', 'https://client.example.com/cb'))
+      .rejects.toThrow(invalid);
+    expect(oauth.verifyPKCE).toHaveBeenCalledWith('bad-verifier', 'chal');
+  });
+
+  it('SDKP-045: a valid exchange issues tokens and audits the issue', async () => {
+    const oauth = makeOauth({ consumeAuthCode: vi.fn(() => pending()) });
+    const audit = makeAudit();
+    const { provider } = makeProvider(oauth, audit);
+    const result = await provider.exchangeAuthorizationCode(
+      clientInfo(), 'code', 'verifier', 'https://client.example.com/cb', new URL('https://trek.example.test/mcp'),
+    );
+    expect(result).toEqual(tokens());
+    expect(oauth.issueTokens).toHaveBeenCalledWith('cid-1', 7, ['trips:read'], null, 'https://trek.example.test/mcp');
+    expect(audit.writeAudit).toHaveBeenCalledWith({
+      userId: 7,
+      action: 'oauth.token.issue',
+      details: { client_id: 'cid-1', scopes: ['trips:read'], audience: 'https://trek.example.test/mcp' },
+      ip: null,
+    });
+  });
+
+  it('SDKP-046: a pending code without a resource issues a null-audience token', async () => {
+    const oauth = makeOauth({ consumeAuthCode: vi.fn(() => pending({ resource: null })) });
+    const { provider } = makeProvider(oauth);
+    await provider.exchangeAuthorizationCode(clientInfo(), 'code');
+    expect(oauth.issueTokens).toHaveBeenCalledWith('cid-1', 7, ['trips:read'], null, null);
+    // No codeVerifier was supplied, so PKCE verification is skipped entirely.
+    expect(oauth.verifyPKCE).not.toHaveBeenCalled();
+  });
+});
+
+describe('TrekOAuthProvider.exchangeRefreshToken', () => {
+  it('SDKP-050: maps invalid_client and generic failures to their legacy messages', async () => {
+    const bad = makeProvider(makeOauth({ refreshTokens: vi.fn(() => ({ error: 'invalid_client' })) }));
+    await expect(bad.provider.exchangeRefreshToken(clientInfo(), 'rt')).rejects.toThrow('Invalid client credentials');
+
+    const expired = makeProvider(makeOauth({ refreshTokens: vi.fn(() => ({ error: 'invalid_grant' })) }));
+    await expect(expired.provider.exchangeRefreshToken(clientInfo(), 'rt')).rejects.toThrow('Refresh token is invalid or expired');
+  });
+
+  it('SDKP-051: success returns the rotated tokens with the client secret forwarded', async () => {
+    const oauth = makeOauth();
+    const { provider } = makeProvider(oauth);
+    const result = await provider.exchangeRefreshToken(clientInfo({ client_secret: 'sec' }), 'rt');
+    expect(result).toEqual(tokens());
+    expect(oauth.refreshTokens).toHaveBeenCalledWith('rt', 'cid-1', 'sec', null);
+  });
+});
+
+describe('TrekOAuthProvider.verifyAccessToken / revokeToken', () => {
+  it('SDKP-060: an unknown token throws; a live one maps to AuthInfo', async () => {
+    const dead = makeProvider(makeOauth({ getUserByAccessToken: vi.fn(() => null) }));
+    await expect(dead.provider.verifyAccessToken('trekoa_dead')).rejects.toThrow('Invalid or expired token');
+
+    const info = {
+      user: { id: 7, username: 'u', email: 'u@example.com', role: 'user' as const },
+      scopes: ['trips:read'],
+      clientId: 'cid-1',
+      audience: null,
+    };
+    const live = makeProvider(makeOauth({ getUserByAccessToken: vi.fn(() => info) }));
+    await expect(live.provider.verifyAccessToken('trekoa_live')).resolves.toEqual({
+      token: 'trekoa_live',
+      clientId: 'cid-1',
+      scopes: ['trips:read'],
+      extra: { user: info.user },
+    });
+  });
+
+  it('SDKP-061: revokeToken delegates with the caller client id and a null ip', async () => {
+    const oauth = makeOauth();
+    const { provider } = makeProvider(oauth);
+    await provider.revokeToken(clientInfo(), { token: 'trekoa_x' });
+    expect(oauth.revokeToken).toHaveBeenCalledWith('trekoa_x', 'cid-1', undefined, null);
+  });
+});
+
+// ─────────────────────────────────────────────────────────────────────────────
+// OauthModule.configure — the SDK routers behind the addon gate
+// ─────────────────────────────────────────────────────────────────────────────
+
+describe('OauthModule.configure', () => {
+  it('SDKP-070: mounts gate + SDK handlers on their prefixes over the injected adapters', () => {
+    const { provider, clients } = makeProvider();
+    const addons = { isAddonEnabled: vi.fn(() => true) } as unknown as AddonsService;
+    const applied: Array<{ handlers: unknown[]; route: string }> = [];
+    const consumer = {
+      apply: vi.fn((...handlers: unknown[]) => ({
+        forRoutes: (route: string) => applied.push({ handlers, route }),
+      })),
+    };
+
+    new OauthModule(addons, provider, clients).configure(consumer as never);
+
+    expect(vi.mocked(authorizationHandler)).toHaveBeenCalledWith({ provider });
+    expect(vi.mocked(clientRegistrationHandler)).toHaveBeenCalledWith({ clientsStore: clients });
+    expect(applied).toHaveLength(2);
+    const [authz, reg] = applied;
+    expect(authz.route).toBe('oauth/authorize');
+    expect(authz.handlers[1]).toBe(sdk.authorizeHandler);
+    expect(reg.route).toBe('oauth/register');
+    expect(reg.handlers[1]).toBe(sdk.registerHandler);
+    // Both mounts share one gate instance, built over the injected AddonsService.
+    expect(authz.handlers[0]).toBe(reg.handlers[0]);
+    const res = { status: vi.fn(() => ({ end: vi.fn() })), end: vi.fn() };
+    (authz.handlers[0] as (rq: unknown, rs: unknown, nx: () => void) => void)({}, res, vi.fn());
+    expect(addons.isAddonEnabled).toHaveBeenCalled();
+  });
+});
diff --git a/server/tests/unit/nest/oauth.service.test.ts b/server/tests/unit/nest/oauth.service.test.ts
index c91cbc7ce..5c579a951 100644
--- a/server/tests/unit/nest/oauth.service.test.ts
+++ b/server/tests/unit/nest/oauth.service.test.ts
@@ -1111,22 +1111,24 @@ describe('branches the legacy suite could not reach', () => {
 });
 
 describe('oauth.bridge delegation', () => {
-  // The bridge is what the SDK-mounted /oauth/authorize path and the MCP
-  // transport reach, both outside the container.
-  it('issues and verifies a token through the bridge instance', () => {
+  // The bridge is down to its one surviving export — what the MCP transport's
+  // token verification reaches outside the container. The SDK provider paths
+  // that used to be bridged live behind the container now (oauth-sdk.provider).
+  it('verifies a container-issued token through the bridge instance', () => {
     const { user } = createUser(testDb);
     const created = makeClient(user.id);
     const clientId = (created.client as { client_id: string }).client_id;
 
-    const tokens = bridge.issueTokens(clientId, user.id, ['trips:read']);
+    const tokens = issueTokens(clientId, user.id, ['trips:read']);
 
     expect(bridge.getUserByAccessToken(tokens.access_token)?.user.id).toBe(user.id);
   });
 
-  it('shares the pending-code map with the container instance', () => {
+  it('shares the pending-code map across service instances', () => {
     // The load-bearing invariant: the consent controller writes the code through
-    // the DI singleton, the SDK provider reads it back through the bridge. Two
-    // maps here would kill the authorization-code flow silently.
+    // the DI singleton, the SDK exchange path reads it back. The map is module-
+    // scoped, so even a second hand-built instance must see it — two maps would
+    // kill the authorization-code flow silently.
     const code = createAuthCode({
       clientId: 'c',
       userId: 42,
@@ -1137,32 +1139,8 @@ describe('oauth.bridge delegation', () => {
       codeChallengeMethod: 'S256',
     })!;
 
-    expect(bridge.consumeAuthCode(code)?.userId).toBe(42);
-  });
-
-  it('verifyPKCE and revokeToken reach the same rows', () => {
-    const { verifier, challenge } = makePkce();
-    expect(bridge.verifyPKCE(verifier, challenge)).toBe(true);
-
-    const { user } = createUser(testDb);
-    const created = makeClient(user.id);
-    const clientId = (created.client as { client_id: string }).client_id;
-    const tokens = issueTokens(clientId, user.id, ['trips:read']);
-
-    bridge.revokeToken(tokens.access_token, clientId, user.id);
-
-    expect(getUserByAccessToken(tokens.access_token)).toBeNull();
-  });
-
-  it('registers a client and refreshes a token pair through the bridge', () => {
-    const { user } = createUser(testDb);
-    const created = bridge.createOAuthClient(user.id, 'Via bridge', ['https://example.com/callback'], ['trips:read']);
-    const client = created.client as { client_id: string; client_secret: string };
-    const tokens = issueTokens(client.client_id, user.id, ['trips:read']);
-
-    const refreshed = bridge.refreshTokens(tokens.refresh_token, client.client_id, client.client_secret);
-
-    expect(refreshed.tokens?.refresh_token).toMatch(/^trekrf_/);
+    const secondInstance = new OauthService(dbs, addonsStub, new AuditService(dbs));
+    expect(secondInstance.consumeAuthCode(code)?.userId).toBe(42);
   });
 });
 
@@ -1173,12 +1151,14 @@ describe('OauthModule', () => {
     const { OauthApiController } = await import('../../../src/nest/oauth/oauth-api.controller');
     const { OauthService: Svc } = await import('../../../src/nest/oauth/oauth.service');
 
+    const { TrekClientsStore, TrekOAuthProvider } = await import('../../../src/nest/oauth/oauth-sdk.provider');
+
     const controllers = Reflect.getMetadata('controllers', OauthModule);
     const providers = Reflect.getMetadata('providers', OauthModule);
     expect(controllers).toEqual([OauthPublicController, OauthApiController]);
     // RateLimitService is deliberately absent: it comes from the global
     // RateLimitModule so all consumers share one set of counters.
-    expect(providers).toEqual([Svc]);
+    expect(providers).toEqual([Svc, TrekClientsStore, TrekOAuthProvider]);
   });
 });
 
diff --git a/server/tests/unit/nest/platform.controller.test.ts b/server/tests/unit/nest/platform.controller.test.ts
index 44684a0aa..ad947414c 100644
--- a/server/tests/unit/nest/platform.controller.test.ts
+++ b/server/tests/unit/nest/platform.controller.test.ts
@@ -4,30 +4,15 @@ import { NotFoundException } from '@nestjs/common';
 // --- hoisted mock fns so the vi.mock factories can reference them -----------------
 const h = vi.hoisted(() => ({
   verifyJwtAndLoadUser: vi.fn(),
-  isAddonEnabled: vi.fn(),
   dbPrepare: vi.fn(),
   existsSync: vi.fn(),
-  // SDK middleware spies — each returns a tagged handler so we can identify which
-  // app.use call received it.
-  authorizeHandler: vi.fn(),
-  registerHandler: vi.fn(),
+  // Tagged handler so we can identify which route registration received it.
   mcpHandler: vi.fn(),
 }));
 
 vi.mock('../../../src/nest/auth/jwt-verify', () => ({ verifyJwtAndLoadUser: h.verifyJwtAndLoadUser }));
 vi.mock('../../../src/db/database', () => ({ db: { prepare: h.dbPrepare } }));
 vi.mock('../../../src/mcp', () => ({ mcpHandler: h.mcpHandler }));
-vi.mock('../../../src/mcp/oauthProvider', () => ({ trekOAuthProvider: {}, trekClientsStore: {} }));
-vi.mock('../../../src/nest/addons/addons.bridge', () => ({ isAddonEnabled: h.isAddonEnabled }));
-
-// SDK handler factories return distinct tagged middleware so we never hit real
-// wiring during registration.
-vi.mock('@modelcontextprotocol/sdk/server/auth/handlers/authorize', () => ({
-  authorizationHandler: vi.fn(() => h.authorizeHandler),
-}));
-vi.mock('@modelcontextprotocol/sdk/server/auth/handlers/register', () => ({
-  clientRegistrationHandler: vi.fn(() => h.registerHandler),
-}));
 
 vi.mock('node:fs', async (orig) => {
   const real = (await orig()) as Record<string, unknown>;
@@ -224,38 +209,6 @@ describe('applyPlatformTransport', () => {
     return calls;
   }
 
-  describe('mcpAddonGate (used on /oauth/authorize + /oauth/register)', () => {
-    function gate() {
-      // The gate is the first handler on the /oauth/authorize use registration.
-      return build().find((c) => c.method === 'use' && c.path === '/oauth/authorize')!.handlers[0];
-    }
-
-    it('404 when MCP is disabled', () => {
-      h.isAddonEnabled.mockReturnValue(false);
-      const res = makeRes();
-      const next = vi.fn();
-      gate()({}, res, next);
-      expect(res.statusCode).toBe(404);
-      expect(next).not.toHaveBeenCalled();
-    });
-
-    it('calls next() when MCP is enabled', () => {
-      h.isAddonEnabled.mockReturnValue(true);
-      const res = makeRes();
-      const next = vi.fn();
-      gate()({}, res, next);
-      expect(next).toHaveBeenCalled();
-    });
-  });
-
-  it('wires the SDK authorize + register handlers behind the gate', () => {
-    const calls = build();
-    const authorize = calls.find((c) => c.path === '/oauth/authorize')!;
-    const register = calls.find((c) => c.path === '/oauth/register')!;
-    expect(authorize.handlers).toContain(h.authorizeHandler);
-    expect(register.handlers).toContain(h.registerHandler);
-  });
-
   it('mounts the MCP handler on POST/GET/DELETE /mcp', () => {
     const calls = build();
     expect(calls.find((c) => c.method === 'post' && c.path === '/mcp')!.handlers[0]).toBe(h.mcpHandler);