@@ -3,6 +3,7 @@ members = [
     "contracts/bulk_payment",
     "contracts/cross_asset_payment",
     "contracts/milestone_escrow",
+    "contracts/orgusd",
     "contracts/revenue_split",
     "contracts/vesting_escrow",
     "contracts/asset_path_payment",
 
@@ -0,0 +1,215 @@
+/**
+ * Integration tests for errorHandlerMiddleware (issue #341)
+ *
+ * Verifies that every error path produces a response matching the standard
+ * shape: { code: string, message: string, details: unknown[] }
+ */
+
+import express, { Request, Response, NextFunction } from 'express';
+import request from 'supertest';
+import { ZodError, z } from 'zod';
+import { errorHandlerMiddleware, HttpError } from '../middlewares/errorHandlerMiddleware.js';
+import { ErrorCodes } from '../utils/apiError.js';
+
+// ── Test app factory ──────────────────────────────────────────────────────────
+
+function makeApp(thrower: (req: Request, res: Response, next: NextFunction) => void) {
+  const app = express();
+  app.use(express.json());
+
+  // Attach a requestId for the middleware to include in responses
+  app.use((req: Request, _res: Response, next: NextFunction) => {
+    req.requestId = 'test-req-id';
+    next();
+  });
+
+  app.get('/test', thrower);
+  app.use(errorHandlerMiddleware);
+  return app;
+}
+
+// ── Helpers ───────────────────────────────────────────────────────────────────
+
+function assertStandardShape(body: Record<string, unknown>) {
+  expect(typeof body.code).toBe('string');
+  expect(typeof body.message).toBe('string');
+  expect(Array.isArray(body.details)).toBe(true);
+}
+
+// ── ZodError ──────────────────────────────────────────────────────────────────
+
+describe('errorHandlerMiddleware — ZodError', () => {
+  it('returns 400 with VALIDATION_ERROR code and issue details', async () => {
+    const app = makeApp((_req, _res, next) => {
+      const schema = z.object({ email: z.string().email() });
+      try {
+        schema.parse({ email: 'not-an-email' });
+      } catch (err) {
+        next(err);
+      }
+    });
+
+    const res = await request(app).get('/test');
+
+    expect(res.status).toBe(400);
+    assertStandardShape(res.body);
+    expect(res.body.code).toBe(ErrorCodes.VALIDATION_ERROR);
+    expect(res.body.details.length).toBeGreaterThan(0);
+    expect(res.body.details[0]).toHaveProperty('path');
+    expect(res.body.details[0]).toHaveProperty('message');
+  });
+});
+
+// ── HTTP-tagged errors ────────────────────────────────────────────────────────
+
+describe('errorHandlerMiddleware — HttpError', () => {
+  it.each([
+    [400, ErrorCodes.BAD_REQUEST, 'Bad input'],
+    [401, ErrorCodes.UNAUTHORIZED, 'Token missing'],
+    [403, ErrorCodes.FORBIDDEN, 'Access denied'],
+    [404, ErrorCodes.NOT_FOUND, 'Not found'],
+    [409, ErrorCodes.CONFLICT, 'Already exists'],
+    [422, ErrorCodes.UNPROCESSABLE, 'Unprocessable'],
+    [429, ErrorCodes.RATE_LIMITED, 'Too many requests'],
+  ])('status %d → code %s', async (status, expectedCode, message) => {
+    const app = makeApp((_req, _res, next) => {
+      const err: HttpError = Object.assign(new Error(message), { status });
+      next(err);
+    });
+
+    const res = await request(app).get('/test');
+
+    expect(res.status).toBe(status);
+    assertStandardShape(res.body);
+    expect(res.body.code).toBe(expectedCode);
+    expect(res.body.message).toBe(message);
+  });
+
+  it('uses the error code field when provided', async () => {
+    const app = makeApp((_req, _res, next) => {
+      const err: HttpError = Object.assign(new Error('Custom'), {
+        status: 400,
+        code: 'CUSTOM_CODE',
+      });
+      next(err);
+    });
+
+    const res = await request(app).get('/test');
+    expect(res.body.code).toBe('CUSTOM_CODE');
+  });
+
+  it('includes details array from the error when provided', async () => {
+    const app = makeApp((_req, _res, next) => {
+      const err: HttpError = Object.assign(new Error('With details'), {
+        status: 422,
+        details: [{ field: 'email', message: 'Invalid format' }],
+      });
+      next(err);
+    });
+
+    const res = await request(app).get('/test');
+    expect(res.body.details).toHaveLength(1);
+    expect(res.body.details[0]).toHaveProperty('field', 'email');
+  });
+});
+
+// ── Client-side JS errors ─────────────────────────────────────────────────────
+
+describe('errorHandlerMiddleware — client JS errors', () => {
+  it.each([
+    ['TypeError',   new TypeError('invalid type')],
+    ['RangeError',  new RangeError('out of range')],
+    ['SyntaxError', new SyntaxError('bad syntax')],
+  ])('%s → 400 BAD_REQUEST', async (_label, err) => {
+    const app = makeApp((_req, _res, next) => next(err));
+
+    const res = await request(app).get('/test');
+
+    expect(res.status).toBe(400);
+    assertStandardShape(res.body);
+    expect(res.body.code).toBe(ErrorCodes.BAD_REQUEST);
+  });
+});
+
+// ── Unhandled / internal errors ───────────────────────────────────────────────
+
+describe('errorHandlerMiddleware — unhandled errors', () => {
+  const originalEnv = process.env.NODE_ENV;
+
+  afterEach(() => {
+    process.env.NODE_ENV = originalEnv;
+  });
+
+  it('returns 500 INTERNAL_ERROR', async () => {
+    const app = makeApp((_req, _res, next) => {
+      next(new Error('Something exploded'));
+    });
+
+    const res = await request(app).get('/test');
+
+    expect(res.status).toBe(500);
+    assertStandardShape(res.body);
+    expect(res.body.code).toBe(ErrorCodes.INTERNAL_ERROR);
+  });
+
+  it('hides the real message in production', async () => {
+    process.env.NODE_ENV = 'production';
+
+    const app = makeApp((_req, _res, next) => {
+      next(new Error('Secret internal detail'));
+    });
+
+    const res = await request(app).get('/test');
+
+    expect(res.status).toBe(500);
+    expect(res.body.message).not.toContain('Secret internal detail');
+    expect(res.body.message).toBe('An unexpected error occurred');
+  });
+
+  it('exposes the message in development', async () => {
+    process.env.NODE_ENV = 'development';
+
+    const app = makeApp((_req, _res, next) => {
+      next(new Error('Dev detail'));
+    });
+
+    const res = await request(app).get('/test');
+
+    expect(res.status).toBe(500);
+    expect(res.body.message).toBe('Dev detail');
+  });
+
+  it('handles non-Error thrown values', async () => {
+    const app = makeApp((_req, _res, next) => {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      next('a plain string error' as any);
+    });
+
+    const res = await request(app).get('/test');
+
+    expect(res.status).toBe(500);
+    assertStandardShape(res.body);
+  });
+});
+
+// ── Standard shape on success ─────────────────────────────────────────────────
+
+describe('errorHandlerMiddleware — shape compliance', () => {
+  it('every error response has code, message, and details fields', async () => {
+    const errors: Error[] = [
+      new Error('generic'),
+      Object.assign(new Error('not found'), { status: 404 }),
+      Object.assign(new Error('rate limited'), { status: 429 }),
+    ];
+
+    for (const err of errors) {
+      const app = makeApp((_req, _res, next) => next(err));
+      const res = await request(app).get('/test');
+
+      expect(res.body).toHaveProperty('code');
+      expect(res.body).toHaveProperty('message');
+      expect(res.body).toHaveProperty('details');
+      expect(Array.isArray(res.body.details)).toBe(true);
+    }
+  });
+});
@@ -25,6 +25,7 @@ import webhookRoutes from './routes/webhookNotificationRoutes.js';
 import notificationRoutes from './routes/notificationRoutes.js';
 import { HealthController } from './controllers/healthController.js';
 import { apiErrorResponse, ErrorCodes } from './utils/apiError.js';
+import { errorHandlerMiddleware } from './middlewares/errorHandlerMiddleware.js';
 
 // Legacy Routes
 import payrollAuditRoutes from './routes/payrollAuditRoutes.js';
@@ -197,15 +198,7 @@ app.use((req, res) => {
 // errorLogger increments Prometheus counters and logs with full context
 app.use(errorLogger);
 
-app.use((err: Error, req: express.Request, res: express.Response, _next: express.NextFunction) => {
-  logger.error(`[${req.requestId}] Unhandled error: ${err.message}`, err);
-  res.status(500).json({
-    ...apiErrorResponse(
-      ErrorCodes.INTERNAL_ERROR,
-      config.nodeEnv === 'development' ? err.message : 'An unexpected error occurred'
-    ),
-    requestId: req.requestId,
-  });
-});
+// Centralized error handler — standardizes ALL error responses (#341)
+app.use(errorHandlerMiddleware);
 
 export default app;
@@ -0,0 +1,113 @@
+-- =============================================================================
+-- Migration 048: Advanced Admin Audit Log (Issue #696)
+-- Purpose : Append-only table that records every action performed by admin
+--           users across the entire platform — employee management, payment
+--           approvals, asset operations, config changes, and more.
+--           Supersedes the narrower org_audit_log (migration 035) for
+--           cross-resource admin-level event tracking.
+-- =============================================================================
+
+-- ---------------------------------------------------------------------------
+-- 1. Enum-style constants (stored as VARCHAR for flexibility)
+--    action_type examples:
+--      employee_created, employee_updated, employee_deleted,
+--      payment_approved, payment_rejected, payment_sent,
+--      asset_issued, asset_frozen, asset_unfrozen, asset_clawback,
+--      user_invited, user_deactivated, user_role_changed,
+--      config_updated, payroll_run_started, payroll_run_completed,
+--      organization_created, organization_deleted, org_setting_changed,
+--      bulk_payment_queued, trustline_authorized, trustline_revoked
+--    severity: info | warning | critical
+-- ---------------------------------------------------------------------------
+
+CREATE TABLE IF NOT EXISTS admin_audit_log (
+  id              BIGSERIAL PRIMARY KEY,
+
+  -- Tenant scope (required — every action belongs to an org)
+  organization_id INTEGER NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
+
+  -- What happened
+  action_type     VARCHAR(80)  NOT NULL,
+
+  -- What kind of resource was affected (e.g. "employee", "payment", "asset")
+  resource_type   VARCHAR(50)  NOT NULL,
+
+  -- Primary key of the affected resource (nullable for bulk / list operations)
+  resource_id     VARCHAR(100),
+
+  -- JSON snapshots for diff-style auditing (nullable when N/A)
+  old_state       JSONB,
+  new_state       JSONB,
+
+  -- Who performed the action
+  actor_id        INTEGER      REFERENCES users(id) ON DELETE SET NULL,
+  actor_email     VARCHAR(255),
+  actor_ip        INET,
+  user_agent      TEXT,
+
+  -- Correlate with request logs
+  request_id      VARCHAR(64),
+
+  -- Severity level: info | warning | critical
+  severity        VARCHAR(20)  NOT NULL DEFAULT 'info'
+                               CHECK (severity IN ('info', 'warning', 'critical')),
+
+  -- Arbitrary extra context (e.g. stellar tx hash, bulk job id)
+  metadata        JSONB,
+
+  -- Immutable timestamp
+  created_at      TIMESTAMPTZ  NOT NULL DEFAULT NOW()
+);
+
+-- ---------------------------------------------------------------------------
+-- 2. Append-only enforcement — prevent UPDATE / DELETE
+-- ---------------------------------------------------------------------------
+CREATE RULE admin_audit_log_no_update
+  AS ON UPDATE TO admin_audit_log DO INSTEAD NOTHING;
+
+CREATE RULE admin_audit_log_no_delete
+  AS ON DELETE TO admin_audit_log DO INSTEAD NOTHING;
+
+-- ---------------------------------------------------------------------------
+-- 3. Indexes for the most common query patterns
+-- ---------------------------------------------------------------------------
+-- Primary lookup: all events for an org, newest-first
+CREATE INDEX IF NOT EXISTS idx_admin_audit_org_time
+  ON admin_audit_log (organization_id, created_at DESC);
+
+-- Filter by action type within an org
+CREATE INDEX IF NOT EXISTS idx_admin_audit_action
+  ON admin_audit_log (organization_id, action_type, created_at DESC);
+
+-- Filter by resource type within an org
+CREATE INDEX IF NOT EXISTS idx_admin_audit_resource
+  ON admin_audit_log (organization_id, resource_type, created_at DESC);
+
+-- Filter by actor within an org
+CREATE INDEX IF NOT EXISTS idx_admin_audit_actor
+  ON admin_audit_log (organization_id, actor_id, created_at DESC);
+
+-- Filter by severity (e.g. "show me all critical events")
+CREATE INDEX IF NOT EXISTS idx_admin_audit_severity
+  ON admin_audit_log (organization_id, severity, created_at DESC);
+
+-- Correlate with request logs
+CREATE INDEX IF NOT EXISTS idx_admin_audit_request_id
+  ON admin_audit_log (request_id)
+  WHERE request_id IS NOT NULL;
+
+-- ---------------------------------------------------------------------------
+-- 4. Comments
+-- ---------------------------------------------------------------------------
+COMMENT ON TABLE  admin_audit_log IS
+  'Append-only log of every administrative action across the PayD platform.';
+COMMENT ON COLUMN admin_audit_log.action_type IS
+  'Machine-readable verb describing the action, e.g. employee_created, payment_approved.';
+COMMENT ON COLUMN admin_audit_log.resource_type IS
+  'Kind of entity the action targeted, e.g. employee, payment, asset, config.';
+COMMENT ON COLUMN admin_audit_log.severity IS
+  'Importance level: info (routine), warning (unusual), critical (security-relevant).';
+COMMENT ON COLUMN admin_audit_log.old_state IS
+  'JSON snapshot of the resource before the action (null for creates).';
+COMMENT ON COLUMN admin_audit_log.new_state IS
+  'JSON snapshot of the resource after the action (null for deletes).';