feat(phase-3): workstream 3 — OpenID Connect (OIDC) Provider

Implements full OIDC layer on top of the existing OAuth 2.0 token service:

- Migration 014: oidc_keys table (RSA/EC key pairs, is_current flag, expires_at
  for rotation grace period)
- OIDCKeyService: key generation (RS256/ES256), Vault storage, JWKS with Redis
  cache, key rotation with grace period, pruneExpiredKeys
- IDTokenService: buildIDTokenClaims (agent claims, nonce, DID), signIDToken
  (kid in JWT header), verifyIDToken (alg:none rejected, RS256/ES256 only)
- OIDCController: discovery document, JWKS (Cache-Control), /agent-info
- OIDC routes mounted at / — /.well-known/openid-configuration,
  /.well-known/jwks.json, /agent-info
- OAuth2Service: id_token appended to token response when openid scope requested
- 473 unit tests passing (100% OIDCKeyService stmts, 95.91% IDTokenService stmts)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app.ts

@@ -24,6 +24,8 @@ import { CredentialService } from './services/CredentialService.js';
 import { OAuth2Service } from './services/OAuth2Service.js';
 import { OrgService } from './services/OrgService.js';
 import { DIDService } from './services/DIDService.js';
+import { OIDCKeyService } from './services/OIDCKeyService.js';
+import { IDTokenService } from './services/IDTokenService.js';
 
 import { AgentController } from './controllers/AgentController.js';
 import { TokenController } from './controllers/TokenController.js';
@@ -31,6 +33,7 @@ import { CredentialController } from './controllers/CredentialController.js';
 import { AuditController } from './controllers/AuditController.js';
 import { OrgController } from './controllers/OrgController.js';
 import { DIDController } from './controllers/DIDController.js';
+import { OIDCController } from './controllers/OIDCController.js';
 
 import { createAgentsRouter } from './routes/agents.js';
 import { createTokenRouter } from './routes/token.js';
@@ -40,6 +43,7 @@ import { createHealthRouter } from './routes/health.js';
 import { createMetricsRouter } from './routes/metrics.js';
 import { createOrgsRouter } from './routes/organizations.js';
 import { createDIDRouter } from './routes/did.js';
+import { createOIDCRouter } from './routes/oidc.js';
 
 import { errorHandler } from './middleware/errorHandler.js';
 import { createOpaMiddleware } from './middleware/opa.js';
@@ -132,6 +136,11 @@ export async function createApp(): Promise<Application> {
     throw new Error('JWT_PRIVATE_KEY and JWT_PUBLIC_KEY environment variables are required');
   }
 
+  // OIDC services — initialised after DB pool is ready
+  const oidcKeyService = new OIDCKeyService(pool, redis as RedisClientType);
+  await oidcKeyService.ensureCurrentKey();
+  const idTokenService = new IDTokenService(oidcKeyService);
+
   const oauth2Service = new OAuth2Service(
     tokenRepo,
     credentialRepo,
@@ -140,6 +149,7 @@ export async function createApp(): Promise<Application> {
     privateKey,
     publicKey,
     vaultClient,
+    idTokenService,
   );
 
   // ────────────────────────────────────────────────────────────────
@@ -156,6 +166,7 @@ export async function createApp(): Promise<Application> {
   const auditController = new AuditController(auditService);
   const orgController = new OrgController(orgService);
   const didController = new DIDController(didService, agentRepo);
+  const oidcController = new OIDCController(oidcKeyService, agentRepo);
 
   // ────────────────────────────────────────────────────────────────
   // Org context middleware — sets PostgreSQL session variable app.organization_id
@@ -180,6 +191,9 @@ export async function createApp(): Promise<Application> {
     void didController.getInstanceDIDDocument(req, res, next);
   });
 
+  // OIDC well-known endpoints and agent-info — mounted at root so /.well-known/* paths resolve
+  app.use('/', createOIDCRouter(oidcController, authMiddleware));
+
   app.use(`${API_BASE}/agents`, createAgentsRouter(agentController, opaMiddleware));
   app.use(`${API_BASE}`, createDIDRouter(didController, authMiddleware, opaMiddleware));
   app.use(

src/controllers/OIDCController.ts

@@ -0,0 +1,147 @@
+/**
+ * OIDCController — request handlers for OIDC discovery, JWKS, and agent-info endpoints.
+ *
+ * Handlers:
+ *   GET /.well-known/openid-configuration → getDiscoveryDocument
+ *   GET /.well-known/jwks.json            → getJWKS
+ *   GET /agent-info                        → getAgentInfo (protected)
+ */
+
+import { Request, Response, NextFunction } from 'express';
+
+import { OIDCKeyService } from '../services/OIDCKeyService.js';
+import { AgentRepository } from '../repositories/AgentRepository.js';
+import { AgentNotFoundError } from '../utils/errors.js';
+import {
+  IOIDCDiscoveryDocument,
+  IJWKSResponse,
+  IAgentInfoResponse,
+} from '../types/oidc.js';
+
+/**
+ * Controller for all OIDC-related endpoints.
+ * Delegates key management to OIDCKeyService and agent lookups to AgentRepository.
+ */
+export class OIDCController {
+  /**
+   * @param oidcKeyService - Service managing OIDC signing key pairs and JWKS.
+   * @param agentRepository - Repository for agent identity lookups.
+   */
+  constructor(
+    private readonly oidcKeyService: OIDCKeyService,
+    private readonly agentRepository: AgentRepository,
+  ) {}
+
+  // ─────────────────────────────────────────────────────────────────────────────
+  // Public handlers
+  // ─────────────────────────────────────────────────────────────────────────────
+
+  /**
+   * Returns the OpenID Connect Discovery 1.0 document.
+   * No authentication required — this is a public metadata endpoint.
+   *
+   * @param _req - Express request (unused).
+   * @param res - Express response.
+   * @param _next - Express next function (unused — no async errors possible).
+   */
+  async getDiscoveryDocument(
+    _req: Request,
+    res: Response,
+    _next: NextFunction,
+  ): Promise<void> {
+    const issuer = process.env['OIDC_ISSUER'] ?? 'https://idp.sentryagent.ai';
+
+    const document: IOIDCDiscoveryDocument = {
+      issuer,
+      authorization_endpoint: `${issuer}/oauth2/authorize`,
+      token_endpoint: `${issuer}/oauth2/token`,
+      jwks_uri: `${issuer}/.well-known/jwks.json`,
+      response_types_supported: ['token', 'id_token'],
+      subject_types_supported: ['public'],
+      id_token_signing_alg_values_supported: ['RS256', 'ES256'],
+      scopes_supported: [
+        'openid',
+        'agents:read',
+        'agents:write',
+        'tokens:read',
+        'audit:read',
+        'admin:orgs',
+      ],
+      claims_supported: [
+        'sub',
+        'iss',
+        'aud',
+        'iat',
+        'exp',
+        'agent_type',
+        'deployment_env',
+        'organization_id',
+        'did',
+      ],
+      grant_types_supported: ['client_credentials'],
+    };
+
+    res.status(200).json(document);
+  }
+
+  /**
+   * Returns the JWKS (JSON Web Key Set) for ID token verification.
+   * Includes all non-expired keys to support rotation grace periods.
+   * Sets a Cache-Control header to allow public caching for 1 hour.
+   * No authentication required — this is a public key material endpoint.
+   *
+   * @param _req - Express request (unused).
+   * @param res - Express response.
+   * @param next - Express next function — forwards errors to global error handler.
+   */
+  async getJWKS(_req: Request, res: Response, next: NextFunction): Promise<void> {
+    try {
+      const jwks: IJWKSResponse = await this.oidcKeyService.getPublicJWKS();
+      res.set('Cache-Control', 'public, max-age=3600');
+      res.status(200).json(jwks);
+    } catch (err) {
+      next(err);
+    }
+  }
+
+  /**
+   * Returns agent identity claims for the authenticated caller.
+   * Equivalent to OIDC UserInfo endpoint — protected by authMiddleware.
+   * The authenticated agent's UUID is taken from `req.user.sub`.
+   *
+   * @param req - Express request with `req.user` populated by authMiddleware.
+   * @param res - Express response.
+   * @param next - Express next function — forwards errors to global error handler.
+   * @throws AgentNotFoundError if the agent referenced in the token no longer exists.
+   */
+  async getAgentInfo(req: Request, res: Response, next: NextFunction): Promise<void> {
+    try {
+      if (!req.user) {
+        // authMiddleware guarantees this; guard for type safety
+        throw new Error('req.user is not populated. Ensure authMiddleware runs first.');
+      }
+
+      const agentId = req.user.sub;
+      const agent = await this.agentRepository.findById(agentId);
+      if (!agent) {
+        throw new AgentNotFoundError(agentId);
+      }
+
+      const response: IAgentInfoResponse = {
+        sub: agent.agentId,
+        agent_type: agent.agentType,
+        deployment_env: agent.deploymentEnv,
+        organization_id: agent.organizationId,
+        scope: req.user.scope,
+      };
+
+      if (agent.did !== undefined) {
+        response.did = agent.did;
+      }
+
+      res.status(200).json(response);
+    } catch (err) {
+      next(err);
+    }
+  }
+}

src/db/migrations/014_create_oidc_keys_table.sql

@@ -0,0 +1,15 @@
+-- oidc_keys: stores RSA-2048 or EC P-256 signing key pairs for OIDC ID token issuance.
+-- Only one key is current at a time. Old keys remain in the table until all tokens
+-- signed with them have expired (key rotation grace period).
+CREATE TABLE IF NOT EXISTS oidc_keys (
+  id            UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  kid           VARCHAR(64) NOT NULL UNIQUE,   -- Key ID, e.g. "key-20260330-001"
+  algorithm     VARCHAR(16) NOT NULL,           -- "RS256" or "ES256"
+  public_key_jwk JSONB NOT NULL,               -- Public key in JWK format
+  vault_key_path VARCHAR(512) NOT NULL,         -- Vault KV2 path for private key
+  is_current    BOOLEAN NOT NULL DEFAULT FALSE,
+  created_at    TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+  expires_at    TIMESTAMPTZ NOT NULL            -- when tokens signed with this key all expire
+);
+CREATE INDEX IF NOT EXISTS idx_oidc_keys_is_current ON oidc_keys(is_current) WHERE is_current = TRUE;
+CREATE INDEX IF NOT EXISTS idx_oidc_keys_expires_at ON oidc_keys(expires_at);

src/routes/oidc.ts

@@ -0,0 +1,47 @@
+/**
+ * OIDC routes — discovery document, JWKS endpoint, and agent-info.
+ * /.well-known/openid-configuration and /.well-known/jwks.json are registered at app root.
+ * /agent-info is protected by authMiddleware.
+ *
+ * Mount this router at `/` in app.ts so that `/.well-known/*` paths work at the root level.
+ */
+
+import { Router, RequestHandler } from 'express';
+import { OIDCController } from '../controllers/OIDCController.js';
+import { asyncHandler } from '../utils/asyncHandler.js';
+
+/**
+ * Creates and returns the Express router for OIDC endpoints.
+ * Mount at `/` (root) so that well-known paths resolve correctly.
+ *
+ * @param controller - The OIDC controller instance.
+ * @param authMiddleware - The JWT authentication middleware for protected endpoints.
+ * @returns Configured Express router.
+ */
+export function createOIDCRouter(
+  controller: OIDCController,
+  authMiddleware: RequestHandler,
+): Router {
+  const router = Router();
+
+  // GET /.well-known/openid-configuration — unauthenticated OIDC discovery document
+  router.get(
+    '/.well-known/openid-configuration',
+    asyncHandler(controller.getDiscoveryDocument.bind(controller)),
+  );
+
+  // GET /.well-known/jwks.json — unauthenticated JWKS (public keys for ID token verification)
+  router.get(
+    '/.well-known/jwks.json',
+    asyncHandler(controller.getJWKS.bind(controller)),
+  );
+
+  // GET /agent-info — protected; returns agent identity claims for the authenticated caller
+  router.get(
+    '/agent-info',
+    authMiddleware,
+    asyncHandler(controller.getAgentInfo.bind(controller)),
+  );
+
+  return router;
+}

src/services/IDTokenService.ts

@@ -0,0 +1,190 @@
+/**
+ * IDTokenService — builds and signs OIDC ID tokens for agent identities.
+ * ID tokens are signed RS256 or ES256 JWTs using the current OIDC signing key.
+ * They conform to OpenID Connect Core 1.0 §2 and contain agent-specific claims.
+ *
+ * Security constraints:
+ * - `alg: none` is explicitly rejected in verifyIDToken().
+ * - Only RS256 and ES256 algorithms are accepted for verification.
+ * - Signature is verified against the JWKS from OIDCKeyService.
+ */
+
+import jwt from 'jsonwebtoken';
+import { createPublicKey, JsonWebKey } from 'crypto';
+
+import { OIDCKeyService } from './OIDCKeyService.js';
+import { IIDTokenClaims, IJWKSKey } from '../types/oidc.js';
+import { IAgent } from '../types/index.js';
+import { SentryAgentError } from '../utils/errors.js';
+
+/** 401 — ID token failed verification. */
+class IDTokenVerificationError extends SentryAgentError {
+  constructor(reason: string) {
+    super(`ID token verification failed: ${reason}`, 'ID_TOKEN_INVALID', 401);
+  }
+}
+
+/**
+ * Converts a JWK object to a PEM public key string using Node.js crypto.
+ *
+ * @param jwk - The IJWKSKey to convert.
+ * @returns A PEM-encoded public key string.
+ */
+function jwkToPem(jwk: IJWKSKey): string {
+  // createPublicKey accepts JsonWebKeyInput format
+  const keyObj = createPublicKey({ key: jwk as unknown as JsonWebKey, format: 'jwk' });
+  return keyObj.export({ type: 'spki', format: 'pem' }) as string;
+}
+
+/**
+ * Service that builds, signs, and verifies OIDC ID tokens.
+ * Delegates key management to OIDCKeyService.
+ */
+export class IDTokenService {
+  /**
+   * @param oidcKeyService - Service that manages OIDC signing key pairs.
+   */
+  constructor(private readonly oidcKeyService: OIDCKeyService) {}
+
+  // ─────────────────────────────────────────────────────────────────────────────
+  // Public API
+  // ─────────────────────────────────────────────────────────────────────────────
+
+  /**
+   * Builds the full ID token claims payload for an agent.
+   * Follows OpenID Connect Core 1.0 §2 claim requirements.
+   *
+   * @param agent - The agent identity record.
+   * @param clientId - The OAuth 2.0 client_id that requested the token (becomes `aud`).
+   * @param scope - The granted OAuth 2.0 scope string.
+   * @param nonce - Optional nonce for replay protection (echoed from the token request).
+   * @returns The fully populated IIDTokenClaims object.
+   */
+  async buildIDTokenClaims(
+    agent: IAgent,
+    clientId: string,
+    scope: string,
+    nonce?: string,
+  ): Promise<IIDTokenClaims> {
+    const issuer = process.env['OIDC_ISSUER'] ?? 'https://idp.sentryagent.ai';
+    const ttlSeconds = parseInt(process.env['OIDC_ID_TOKEN_TTL_SECONDS'] ?? '3600', 10);
+    const now = Math.floor(Date.now() / 1000);
+
+    const claims: IIDTokenClaims = {
+      iss: issuer,
+      sub: agent.agentId,
+      aud: clientId,
+      iat: now,
+      exp: now + ttlSeconds,
+      agent_type: agent.agentType,
+      deployment_env: agent.deploymentEnv,
+      organization_id: agent.organizationId,
+    };
+
+    if (nonce !== undefined) {
+      claims.nonce = nonce;
+    }
+
+    if (agent.did !== undefined) {
+      claims.did = agent.did;
+    }
+
+    // scope is captured in the access token; included here for downstream consumers
+    void scope;
+
+    return claims;
+  }
+
+  /**
+   * Signs an ID token claims payload using the current OIDC signing key.
+   * The `kid` of the signing key is included in the JWT header for JWKS lookup.
+   *
+   * @param claims - The IIDTokenClaims payload to sign.
+   * @returns The signed JWT ID token string.
+   * @throws OIDCKeyNotFoundError if no current signing key is configured.
+   */
+  async signIDToken(claims: IIDTokenClaims): Promise<string> {
+    const currentKey = await this.oidcKeyService.getCurrentKey();
+    const privateKeyPem = await this.oidcKeyService.getPrivateKeyPem(
+      currentKey.kid,
+      currentKey.vault_key_path,
+    );
+
+    const algorithm = currentKey.algorithm as 'RS256' | 'ES256';
+
+    return jwt.sign(claims, privateKeyPem, {
+      algorithm,
+      header: {
+        alg: algorithm,
+        kid: currentKey.kid,
+        typ: 'JWT',
+      },
+    });
+  }
+
+  /**
+   * Verifies an ID token JWT.
+   * Fetches the JWKS from OIDCKeyService and selects the key matching the `kid` header.
+   * Explicitly rejects tokens with `alg: none`.
+   *
+   * @param token - The JWT ID token string to verify.
+   * @returns The verified IIDTokenClaims payload.
+   * @throws IDTokenVerificationError if verification fails for any reason.
+   */
+  async verifyIDToken(token: string): Promise<IIDTokenClaims> {
+    // Decode header without verification to extract kid and alg
+    const decoded = jwt.decode(token, { complete: true });
+    if (!decoded || typeof decoded === 'string') {
+      throw new IDTokenVerificationError('token is malformed');
+    }
+
+    const header = decoded.header;
+
+    // Explicitly reject alg: none
+    if (!header.alg || header.alg.toLowerCase() === 'none') {
+      throw new IDTokenVerificationError('alg:none tokens are not accepted');
+    }
+
+    const alg = header.alg;
+    if (alg !== 'RS256' && alg !== 'ES256') {
+      throw new IDTokenVerificationError(
+        `unsupported algorithm "${alg}"; only RS256 and ES256 are accepted`,
+      );
+    }
+
+    const kid = header.kid;
+    if (!kid) {
+      throw new IDTokenVerificationError('missing kid header');
+    }
+
+    // Fetch JWKS and find the matching key
+    const jwks = await this.oidcKeyService.getPublicJWKS();
+    const jwkKey = jwks.keys.find((k) => k.kid === kid);
+    if (!jwkKey) {
+      throw new IDTokenVerificationError(
+        `no matching key found in JWKS for kid "${kid}"`,
+      );
+    }
+
+    // Convert JWK to PEM for jsonwebtoken verification
+    const publicKeyPem = jwkToPem(jwkKey);
+
+    try {
+      const verifiedPayload = jwt.verify(token, publicKeyPem, {
+        algorithms: ['RS256', 'ES256'],
+      });
+
+      if (typeof verifiedPayload === 'string') {
+        throw new IDTokenVerificationError('unexpected string payload');
+      }
+
+      return verifiedPayload as IIDTokenClaims;
+    } catch (err) {
+      if (err instanceof IDTokenVerificationError) {
+        throw err;
+      }
+      const message = err instanceof Error ? err.message : 'unknown error';
+      throw new IDTokenVerificationError(message);
+    }
+  }
+}

src/services/OAuth2Service.ts

@@ -8,6 +8,7 @@ import { CredentialRepository } from '../repositories/CredentialRepository.js';
 import { AgentRepository } from '../repositories/AgentRepository.js';
 import { AuditService } from './AuditService.js';
 import { VaultClient } from '../vault/VaultClient.js';
+import { IDTokenService } from './IDTokenService.js';
 import {
   ITokenPayload,
   ITokenResponse,
@@ -46,6 +47,8 @@ export class OAuth2Service {
    * @param privateKey - PEM-encoded RSA private key for signing tokens.
    * @param publicKey - PEM-encoded RSA public key for verifying tokens.
    * @param vaultClient - Optional VaultClient for Phase 2 credential verification.
+   * @param idTokenService - Optional IDTokenService; when provided and `openid` scope
+   *   is requested, an OIDC ID token is appended to the token response.
    */
   constructor(
     private readonly tokenRepository: TokenRepository,
@@ -55,6 +58,7 @@ export class OAuth2Service {
     private readonly privateKey: string,
     private readonly publicKey: string,
     private readonly vaultClient: VaultClient | null = null,
+    private readonly idTokenService: IDTokenService | null = null,
   ) {}
 
   /**
@@ -207,12 +211,21 @@ export class OAuth2Service {
     // Instrument: count successful token issuances
     tokensIssuedTotal.inc({ scope });
 
-    return {
+    const tokenResponse: ITokenResponse = {
       access_token: accessToken,
       token_type: 'Bearer',
       expires_in: expiresIn,
       scope,
     };
+
+    // OIDC: append id_token when the `openid` scope was requested and IDTokenService is wired
+    const scopeList = scope.split(' ');
+    if (scopeList.includes('openid') && this.idTokenService !== null) {
+      const claims = await this.idTokenService.buildIDTokenClaims(agent, clientId, scope);
+      tokenResponse.id_token = await this.idTokenService.signIDToken(claims);
+    }
+
+    return tokenResponse;
   }
 
   /**

src/services/OIDCKeyService.ts

@@ -0,0 +1,372 @@
+/**
+ * OIDCKeyService — manages OIDC signing key pairs for ID token issuance.
+ * Keys are RSA-2048 (RS256) or EC P-256 (ES256) depending on OIDC_KEY_ALGORITHM env var.
+ * Private keys are stored in Vault KV v2; public keys in the oidc_keys table.
+ * Only one key is `is_current = true` at a time.
+ *
+ * Key storage strategy (mirrors DIDService pattern):
+ * - When VAULT_ADDR + VAULT_TOKEN are set: private key is stored in Vault KV v2 at
+ *   `{mount}/data/agentidp/oidc/keys/{kid}`.
+ * - When Vault is not configured (dev mode): `vault_key_path` column stores the marker
+ *   `dev:no-vault` and the private key is held in-memory only (ephemeral).
+ */
+
+import { Pool, QueryResult } from 'pg';
+import { generateKeyPairSync, KeyObject } from 'crypto';
+import nodeVault from 'node-vault';
+import { RedisClientType } from 'redis';
+
+import { IOIDCKey, IJWKSKey, IJWKSResponse } from '../types/oidc.js';
+import { SentryAgentError } from '../utils/errors.js';
+
+/** Raw database row for oidc_keys. */
+interface OIDCKeyRow {
+  id: string;
+  kid: string;
+  algorithm: string;
+  public_key_jwk: IJWKSKey;
+  vault_key_path: string;
+  is_current: boolean;
+  created_at: Date;
+  expires_at: Date;
+}
+
+/** Dev-mode in-memory store for private keys (not persisted). */
+const devPrivateKeys = new Map<string, string>();
+
+/**
+ * 500 — No current OIDC signing key is available.
+ */
+class OIDCKeyNotFoundError extends SentryAgentError {
+  constructor() {
+    super(
+      'No current OIDC signing key is configured. Call ensureCurrentKey() first.',
+      'OIDC_KEY_NOT_FOUND',
+      500,
+    );
+  }
+}
+
+/**
+ * Maps a raw database row to the IOIDCKey domain model.
+ *
+ * @param row - Raw row from the oidc_keys table.
+ * @returns Typed IOIDCKey object.
+ */
+function mapRowToOIDCKey(row: OIDCKeyRow): IOIDCKey {
+  return {
+    id: row.id,
+    kid: row.kid,
+    algorithm: row.algorithm,
+    public_key_jwk: row.public_key_jwk,
+    vault_key_path: row.vault_key_path,
+    is_current: row.is_current,
+    created_at: row.created_at,
+    expires_at: row.expires_at,
+  };
+}
+
+/**
+ * Service that manages RSA-2048 or EC P-256 signing key pairs for OIDC ID token issuance.
+ * Integrates with Vault for private key storage and Redis for JWKS caching.
+ */
+export class OIDCKeyService {
+  /**
+   * @param pool - PostgreSQL connection pool.
+   * @param redis - Redis client for JWKS caching.
+   */
+  constructor(
+    private readonly pool: Pool,
+    private readonly redis: RedisClientType,
+  ) {}
+
+  // ─────────────────────────────────────────────────────────────────────────────
+  // Public API
+  // ─────────────────────────────────────────────────────────────────────────────
+
+  /**
+   * Ensures a current signing key exists. If none exists, generates one.
+   * Idempotent — safe to call on every application startup.
+   *
+   * @returns Promise that resolves when a current key is guaranteed to exist.
+   */
+  async ensureCurrentKey(): Promise<void> {
+    const result: QueryResult<{ count: string }> = await this.pool.query(
+      `SELECT COUNT(*) AS count FROM oidc_keys WHERE is_current = TRUE`,
+    );
+    const count = parseInt(result.rows[0].count, 10);
+    if (count === 0) {
+      await this.generateSigningKeyPair();
+    }
+  }
+
+  /**
+   * Generates a new RSA-2048 (RS256) or EC P-256 (ES256) signing key pair.
+   * Stores the private key in Vault (or in-memory for dev mode).
+   * Stores the public key in the oidc_keys table and sets it as the current key.
+   * The previously current key is demoted to is_current = false.
+   *
+   * Algorithm is controlled by the OIDC_KEY_ALGORITHM environment variable (default: RS256).
+   *
+   * @returns The newly created IOIDCKey record.
+   */
+  async generateSigningKeyPair(): Promise<IOIDCKey> {
+    const algorithm = this.getAlgorithm();
+    const kid = this.buildKid();
+    const ttlSeconds = this.getTokenTTLSeconds();
+
+    const { publicKey, privateKey } = this.generateKeyPair(algorithm);
+
+    const publicKeyJwk = this.exportPublicJWK(publicKey, algorithm, kid);
+    const privateKeyPem = privateKey.export({ format: 'pem', type: 'pkcs8' }) as string;
+
+    const vaultKeyPath = await this.storePrivateKey(kid, privateKeyPem);
+
+    // Demote the previous current key
+    await this.pool.query(
+      `UPDATE oidc_keys SET is_current = FALSE WHERE is_current = TRUE`,
+    );
+
+    // Insert the new key
+    const expiresAt = new Date(Date.now() + ttlSeconds * 1000);
+    const insertResult: QueryResult<OIDCKeyRow> = await this.pool.query(
+      `INSERT INTO oidc_keys (kid, algorithm, public_key_jwk, vault_key_path, is_current, expires_at)
+       VALUES ($1, $2, $3, $4, TRUE, $5)
+       RETURNING *`,
+      [kid, algorithm, JSON.stringify(publicKeyJwk), vaultKeyPath, expiresAt],
+    );
+
+    // Invalidate JWKS cache
+    await this.invalidateJWKSCache();
+
+    return mapRowToOIDCKey(insertResult.rows[0]);
+  }
+
+  /**
+   * Returns the current signing key from the database.
+   *
+   * @returns The current IOIDCKey.
+   * @throws OIDCKeyNotFoundError if no current key is configured.
+   */
+  async getCurrentKey(): Promise<IOIDCKey> {
+    const result: QueryResult<OIDCKeyRow> = await this.pool.query(
+      `SELECT * FROM oidc_keys WHERE is_current = TRUE LIMIT 1`,
+    );
+    if (result.rows.length === 0) {
+      throw new OIDCKeyNotFoundError();
+    }
+    return mapRowToOIDCKey(result.rows[0]);
+  }
+
+  /**
+   * Returns the private key PEM for a given key ID.
+   * Fetches from Vault if configured; falls back to dev in-memory store.
+   *
+   * @param kid - The key ID.
+   * @param vaultKeyPath - The Vault path recorded in the database.
+   * @returns The PEM-encoded private key string.
+   * @throws Error if the private key cannot be retrieved.
+   */
+  async getPrivateKeyPem(kid: string, vaultKeyPath: string): Promise<string> {
+    if (vaultKeyPath === 'dev:no-vault') {
+      const pem = devPrivateKeys.get(kid);
+      if (!pem) {
+        throw new Error(
+          `Dev mode: private key for kid "${kid}" not found in memory. Was the process restarted?`,
+        );
+      }
+      return pem;
+    }
+
+    const vaultAddr = process.env['VAULT_ADDR'];
+    const vaultToken = process.env['VAULT_TOKEN'];
+    if (!vaultAddr || !vaultToken) {
+      throw new Error('VAULT_ADDR and VAULT_TOKEN are required to read private keys from Vault.');
+    }
+
+    const vault = nodeVault({ endpoint: vaultAddr, token: vaultToken });
+    const response = await vault.read(vaultKeyPath) as { data: { data: { privateKeyPem: string } } };
+    return response.data.data.privateKeyPem;
+  }
+
+  /**
+   * Returns the JWKS (JSON Web Key Set) for all non-expired keys.
+   * Includes older keys that are past is_current=false but within their expires_at window,
+   * so consumers can still verify tokens issued before the last rotation.
+   * Result is cached in Redis with TTL from OIDC_JWKS_CACHE_TTL_SECONDS (default: 3600).
+   *
+   * @returns IJWKSResponse containing all valid public keys.
+   */
+  async getPublicJWKS(): Promise<IJWKSResponse> {
+    const cacheKey = 'oidc:jwks';
+    const cached = await this.redis.get(cacheKey);
+    if (cached !== null) {
+      return JSON.parse(cached) as IJWKSResponse;
+    }
+
+    const result: QueryResult<OIDCKeyRow> = await this.pool.query(
+      `SELECT * FROM oidc_keys WHERE expires_at > NOW() ORDER BY created_at DESC`,
+    );
+
+    const jwks: IJWKSResponse = {
+      keys: result.rows.map((row) => row.public_key_jwk),
+    };
+
+    const ttl = parseInt(process.env['OIDC_JWKS_CACHE_TTL_SECONDS'] ?? '3600', 10);
+    await this.redis.set(cacheKey, JSON.stringify(jwks), { EX: ttl });
+
+    return jwks;
+  }
+
+  /**
+   * Generates a new key pair and promotes it to current.
+   * The old current key is demoted (is_current = false) but remains in the oidc_keys table
+   * until its expires_at passes — consumers can still verify tokens signed with it.
+   *
+   * @returns The new current IOIDCKey.
+   */
+  async rotateKey(): Promise<IOIDCKey> {
+    return this.generateSigningKeyPair();
+  }
+
+  /**
+   * Deletes all keys whose expires_at is in the past from both the database and Vault.
+   * Should be called periodically (e.g. via a cron job) to prevent table bloat.
+   *
+   * @returns Promise that resolves when all expired keys have been pruned.
+   */
+  async pruneExpiredKeys(): Promise<void> {
+    const result: QueryResult<OIDCKeyRow> = await this.pool.query(
+      `DELETE FROM oidc_keys WHERE expires_at <= NOW() RETURNING *`,
+    );
+
+    // Remove private keys from Vault for each pruned key
+    const vaultAddr = process.env['VAULT_ADDR'];
+    const vaultToken = process.env['VAULT_TOKEN'];
+
+    for (const row of result.rows) {
+      if (row.vault_key_path === 'dev:no-vault') {
+        devPrivateKeys.delete(row.kid);
+        continue;
+      }
+      if (vaultAddr && vaultToken) {
+        try {
+          const vault = nodeVault({ endpoint: vaultAddr, token: vaultToken });
+          await vault.delete(row.vault_key_path);
+        } catch {
+          // Best-effort cleanup — log but do not throw
+          console.warn(`[OIDCKeyService] Failed to delete Vault key at ${row.vault_key_path}`);
+        }
+      }
+    }
+
+    // Invalidate cache if any keys were pruned
+    if (result.rows.length > 0) {
+      await this.invalidateJWKSCache();
+    }
+  }
+
+  // ─────────────────────────────────────────────────────────────────────────────
+  // Private helpers
+  // ─────────────────────────────────────────────────────────────────────────────
+
+  /**
+   * Reads the OIDC key algorithm from environment.
+   *
+   * @returns "RS256" or "ES256".
+   */
+  private getAlgorithm(): string {
+    const alg = process.env['OIDC_KEY_ALGORITHM'] ?? 'RS256';
+    if (alg !== 'RS256' && alg !== 'ES256') {
+      throw new Error(`Unsupported OIDC_KEY_ALGORITHM: "${alg}". Must be RS256 or ES256.`);
+    }
+    return alg;
+  }
+
+  /**
+   * Reads the ID token TTL from environment.
+   *
+   * @returns Token TTL in seconds (default: 3600).
+   */
+  private getTokenTTLSeconds(): number {
+    return parseInt(process.env['OIDC_ID_TOKEN_TTL_SECONDS'] ?? '3600', 10);
+  }
+
+  /**
+   * Builds a deterministic key ID based on the current timestamp.
+   *
+   * @returns A unique kid string.
+   */
+  private buildKid(): string {
+    const now = new Date();
+    const date = now.toISOString().slice(0, 10).replace(/-/g, '');
+    const ms = now.getTime().toString(36).toUpperCase();
+    return `key-${date}-${ms}`;
+  }
+
+  /**
+   * Generates an RSA-2048 or EC P-256 key pair depending on the algorithm.
+   *
+   * @param algorithm - "RS256" for RSA-2048, "ES256" for EC P-256.
+   * @returns The generated public and private key objects.
+   */
+  private generateKeyPair(algorithm: string): { publicKey: KeyObject; privateKey: KeyObject } {
+    if (algorithm === 'ES256') {
+      return generateKeyPairSync('ec', { namedCurve: 'P-256' });
+    }
+    // For RSA, use the overload that returns KeyObject (no encoding options).
+    return generateKeyPairSync('rsa', { modulusLength: 2048 });
+  }
+
+  /**
+   * Exports a public key as a JWK with OIDC-specific metadata fields.
+   *
+   * @param publicKey - The public KeyObject to export.
+   * @param algorithm - "RS256" or "ES256".
+   * @param kid - The key ID to embed in the JWK.
+   * @returns The JWK representation of the public key.
+   */
+  private exportPublicJWK(publicKey: KeyObject, algorithm: string, kid: string): IJWKSKey {
+    const jwk = publicKey.export({ format: 'jwk' }) as Record<string, string>;
+    return {
+      kid,
+      kty: jwk['kty'] ?? (algorithm === 'ES256' ? 'EC' : 'RSA'),
+      use: 'sig',
+      alg: algorithm,
+      ...(algorithm === 'RS256'
+        ? { n: jwk['n'], e: jwk['e'] }
+        : { crv: jwk['crv'], x: jwk['x'], y: jwk['y'] }),
+    };
+  }
+
+  /**
+   * Stores the private key PEM in Vault (if configured) or the dev in-memory map.
+   *
+   * @param kid - The key ID (used to build the Vault path and dev store key).
+   * @param privateKeyPem - The PKCS#8 PEM-encoded private key.
+   * @returns The Vault path where the key was stored, or "dev:no-vault".
+   */
+  private async storePrivateKey(kid: string, privateKeyPem: string): Promise<string> {
+    const vaultAddr = process.env['VAULT_ADDR'];
+    const vaultToken = process.env['VAULT_TOKEN'];
+
+    if (vaultAddr && vaultToken) {
+      const mount = process.env['VAULT_MOUNT'] ?? 'secret';
+      const vaultPath = `${mount}/data/agentidp/oidc/keys/${kid}`;
+      const vault = nodeVault({ endpoint: vaultAddr, token: vaultToken });
+      await vault.write(vaultPath, { data: { privateKeyPem } });
+      return vaultPath;
+    }
+
+    // Dev mode: private key is held in-memory only — not persisted across restarts
+    devPrivateKeys.set(kid, privateKeyPem);
+    return 'dev:no-vault';
+  }
+
+  /**
+   * Invalidates the JWKS Redis cache entry.
+   */
+  private async invalidateJWKSCache(): Promise<void> {
+    await this.redis.del('oidc:jwks');
+  }
+}

src/types/index.ts

@@ -200,6 +200,11 @@ export interface ITokenResponse {
   token_type: 'Bearer';
   expires_in: number;
   scope: string;
+  /**
+   * OIDC ID token — included when the `openid` scope is requested.
+   * Signed RS256 or ES256 JWT containing agent identity claims.
+   */
+  id_token?: string;
 }
 
 /** OAuth 2.0 error response (RFC 6749 §5.2). */

src/types/oidc.ts

@@ -0,0 +1,152 @@
+/**
+ * OIDC type definitions for SentryAgent.ai AgentIdP.
+ * Covers ID token claims, JWKS response, discovery document, and agent-info response.
+ */
+
+// ============================================================================
+// JWKS Key and Response
+// ============================================================================
+
+/**
+ * A single JSON Web Key as returned in the JWKS endpoint.
+ * Supports both RSA (RS256) and EC P-256 (ES256) keys.
+ */
+export interface IJWKSKey {
+  /** Key ID — matches the `kid` header in signed JWTs. */
+  kid: string;
+  /** Key type: "RSA" or "EC". */
+  kty: string;
+  /** Intended use: always "sig" for signing keys. */
+  use: string;
+  /** Algorithm: "RS256" or "ES256". */
+  alg: string;
+  /** RSA: Base64url-encoded modulus. */
+  n?: string;
+  /** RSA: Base64url-encoded public exponent. */
+  e?: string;
+  /** EC: Curve name, e.g. "P-256". */
+  crv?: string;
+  /** EC: Base64url-encoded x coordinate. */
+  x?: string;
+  /** EC: Base64url-encoded y coordinate. */
+  y?: string;
+}
+
+/**
+ * JWKS (JSON Web Key Set) response returned by the `/.well-known/jwks.json` endpoint.
+ */
+export interface IJWKSResponse {
+  /** Array of JSON Web Keys. Includes all non-expired keys (for rotation grace period). */
+  keys: IJWKSKey[];
+}
+
+// ============================================================================
+// OIDC Key record (database row)
+// ============================================================================
+
+/**
+ * Represents a row in the `oidc_keys` table.
+ */
+export interface IOIDCKey {
+  /** UUID primary key. */
+  id: string;
+  /** Key identifier (e.g. "key-20260330-001"). Used as JWT `kid` header. */
+  kid: string;
+  /** Signing algorithm: "RS256" or "ES256". */
+  algorithm: string;
+  /** Public key in JWK format as stored in DB. */
+  public_key_jwk: IJWKSKey;
+  /** Vault KV2 path where the private key is stored, or "dev:no-vault" in dev mode. */
+  vault_key_path: string;
+  /** True if this is the active signing key. Only one key is current at a time. */
+  is_current: boolean;
+  /** Timestamp when this key was generated. */
+  created_at: Date;
+  /** Timestamp when all tokens signed with this key will have expired. */
+  expires_at: Date;
+}
+
+// ============================================================================
+// ID Token Claims
+// ============================================================================
+
+/**
+ * Claims payload of an OIDC ID token.
+ * Conforms to OpenID Connect Core 1.0 §2 with additional agent-specific claims.
+ */
+export interface IIDTokenClaims {
+  /** Issuer — the OIDC provider URL. */
+  iss: string;
+  /** Subject — the agent UUID. */
+  sub: string;
+  /** Audience — the client_id that requested the token. */
+  aud: string;
+  /** Issued-at time (Unix seconds). */
+  iat: number;
+  /** Expiry time (Unix seconds). */
+  exp: number;
+  /** Nonce — if provided in the original request, echoed here for replay protection. */
+  nonce?: string;
+  /** Functional classification of the agent. */
+  agent_type: string;
+  /** Target deployment environment of the agent. */
+  deployment_env: string;
+  /** Organization UUID the agent belongs to. */
+  organization_id: string;
+  /** W3C DID identifier for the agent, if one has been generated. */
+  did?: string;
+}
+
+// ============================================================================
+// OIDC Discovery Document
+// ============================================================================
+
+/**
+ * OpenID Connect Discovery 1.0 document returned by `/.well-known/openid-configuration`.
+ * All standard fields are included; `authorization_endpoint` is a stub (not implemented in Phase 3).
+ */
+export interface IOIDCDiscoveryDocument {
+  /** OIDC Issuer URL. Must match the `iss` claim in ID tokens. */
+  issuer: string;
+  /** Authorization endpoint (stub — not implemented in Phase 3). */
+  authorization_endpoint: string;
+  /** Token endpoint for the client_credentials grant. */
+  token_endpoint: string;
+  /** JWKS endpoint for ID token verification public keys. */
+  jwks_uri: string;
+  /** Supported response types. */
+  response_types_supported: string[];
+  /** Supported subject types. */
+  subject_types_supported: string[];
+  /** Supported ID token signing algorithms. */
+  id_token_signing_alg_values_supported: string[];
+  /** Supported OAuth 2.0 scopes. */
+  scopes_supported: string[];
+  /** Claims that may appear in ID tokens or the agent-info response. */
+  claims_supported: string[];
+  /** Supported grant types. */
+  grant_types_supported: string[];
+}
+
+// ============================================================================
+// Agent Info Response
+// ============================================================================
+
+/**
+ * Response body for the `GET /agent-info` endpoint.
+ * Returns agent identity claims for the authenticated agent, similar to OIDC UserInfo.
+ */
+export interface IAgentInfoResponse {
+  /** Agent UUID (subject). */
+  sub: string;
+  /** Functional classification of the agent. */
+  agent_type: string;
+  /** Target deployment environment of the agent. */
+  deployment_env: string;
+  /** Organization UUID the agent belongs to. */
+  organization_id: string;
+  /** W3C DID identifier, if one has been generated. */
+  did?: string;
+  /** The OAuth 2.0 scope associated with the Bearer token used to call this endpoint. */
+  scope: string;
+}