diff --git a/README.md b/README.md
index cb4de9a..5a0c63d 100644
--- a/README.md
+++ b/README.md
@@ -381,3 +381,6 @@ Notes:
 This repo is part of [Callora](https://github.com/your-org/callora):
 - Frontend: `callora-frontend`
 - Contracts: `callora-contracts`
+
+## Security Audit Logging
+Admin events are routed into an isolated, structured Pino log stream containing the channel label `admin_action` for clean alerting profiles.
diff --git a/src/errors/codes.ts b/src/errors/codes.ts
index fbbeb6d..7a84f1d 100644
--- a/src/errors/codes.ts
+++ b/src/errors/codes.ts
@@ -244,10 +244,7 @@ export const ErrorCode = {
   UNSUPPORTED_MEDIA_TYPE: "UNSUPPORTED_MEDIA_TYPE",
 
   /** Request is syntactically correct but semantically invalid */
-  UNPROCESSABLE_ENTITY: "UNPROCESSABLE_ENTITY",
-
-  /** Usage aggregate not found for the given developer */
-  USAGE_AGGREGATE_NOT_FOUND: "USAGE_AGGREGATE_NOT_FOUND"
+  UNPROCESSABLE_ENTITY: "UNPROCESSABLE_ENTITY"
 
 } as const;
 
diff --git a/src/middleware/adminLog.test.ts b/src/middleware/adminLog.test.ts
new file mode 100644
index 0000000..ca33100
--- /dev/null
+++ b/src/middleware/adminLog.test.ts
@@ -0,0 +1,56 @@
+import { adminLogMiddleware, adminLogger } from './adminLog.js';
+import { type Request, type Response } from 'express';
+
+describe('Admin Logging Middleware', () => {
+  let mockRequest: Partial<Request>;
+  let mockResponse: Partial<Response>;
+  let nextFunction = jest.fn();
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+    jest.spyOn(adminLogger, 'info').mockImplementation(() => adminLogger);
+
+    mockRequest = {
+      method: 'POST',
+      path: '/users',
+      baseUrl: '/api/admin',
+      ip: '127.0.0.1',
+      get: jest.fn().mockReturnValue('test-agent'),
+    };
+
+    const callbacks: Record<string, () => void> = {};
+    mockResponse = {
+      statusCode: 201,
+      locals: { adminActor: 'admin@callora.io' },
+      on: jest.fn().mockImplementation((event, callback) => {
+        callbacks[event] = callback;
+        return mockResponse;
+      }),
+    };
+
+    // Simulate response ending to trigger the logger
+    (mockResponse.on as jest.Mock).mockImplementation((event, callback) => {
+      if (event === 'finish') setTimeout(callback, 0);
+        return mockResponse;
+    });
+  });
+
+  it('should successfully pass to next and log structured admin metadata', (done) => {
+    adminLogMiddleware(mockRequest as Request, mockResponse as Response, nextFunction);
+
+    expect(nextFunction).toHaveBeenCalled();
+    
+    setTimeout(() => {
+      expect(adminLogger.info).toHaveBeenCalledWith(
+        expect.objectContaining({
+          method: 'POST',
+          path: '/api/admin/users',
+          statusCode: 201,
+          actor: 'admin@callora.io',
+        }),
+        expect.any(String)
+      );
+      done();
+    }, 5);
+  });
+});
diff --git a/src/middleware/adminLog.ts b/src/middleware/adminLog.ts
new file mode 100644
index 0000000..36279ac
--- /dev/null
+++ b/src/middleware/adminLog.ts
@@ -0,0 +1,31 @@
+import { type Request, type Response, type NextFunction } from 'express';
+import { logger } from './logging.js';
+
+// Create a dedicated pino child logger for admin actions separate from standard requests
+export const adminLogger = logger.child({
+  channel: 'admin_action',
+});
+
+export const adminLogMiddleware = (req: Request, res: Response, next: NextFunction): void => {
+  const startTime = process.hrtime.bigint();
+
+  res.on('finish', () => {
+    const endTime = process.hrtime.bigint();
+    const durationMs = Number(endTime - startTime) / 1_000_000;
+
+    // Use the route's authenticated actor field if available
+    const actor = res.locals.adminActor || 'unknown_admin';
+
+    adminLogger.info({
+      method: req.method,
+      path: req.baseUrl + req.path,
+      statusCode: res.statusCode,
+      actor,
+      durationMs,
+      ip: req.ip,
+      userAgent: req.get('user-agent'),
+    }, `Admin action completed: ${req.method} ${req.baseUrl}${req.path}`);
+  });
+
+  next();
+};
diff --git a/src/routes/admin.ts b/src/routes/admin.ts
index a692bb9..1fd0dc5 100644
--- a/src/routes/admin.ts
+++ b/src/routes/admin.ts
@@ -1,3 +1,4 @@
+import { adminLogMiddleware } from '../middleware/adminLog.js';
 import { Router, type Response } from 'express';
 import { adminAuth } from '../middleware/adminAuth.js';
 import { createAdminIpAllowlist } from '../middleware/ipAllowlist.js';
@@ -24,7 +25,7 @@ const router = Router();
 // Apply IP allowlist check before authentication
 router.use(createAdminIpAllowlist());
 router.use(adminAuth);
-
+router.use(adminLogMiddleware); // <--- Add this line here!
 router.get('/users', async (req, res, next) => {
   try {
     const { limit, offset } = parsePagination(req.query as Record<string, string>);
@@ -211,4 +212,4 @@ router.use('/webhooks', createAdminWebhooksRouter());
 // ---------------------------------------------------------------------------
 router.use('/apis', createAdminApisRouter());
 
-export default router;
\ No newline at end of file
+export default router;