diff --git a/.ralph/fix_plan.md b/.ralph/fix_plan.md
index 0de9e47..9526f3e 100644
--- a/.ralph/fix_plan.md
+++ b/.ralph/fix_plan.md
@@ -385,14 +385,14 @@ Spec: `.ralph/specs/phase-18-cli-cicd.md`
 
 ---
 
-## Phase 23: Observability [PENDIENTE]
+## Phase 23: Observability [COMPLETO]
 
-- [ ] 23.1: Request correlation: requestId en CADA log entry via pino child logger
-- [ ] 23.2: Structured error logging con contexto (userId, sessionId, etc.)
-- [ ] 23.3: Liveness probe: GET /health/live
-- [ ] 23.4: Readiness probe: GET /health/ready (DB + job queue check)
-- [ ] 23.5: Startup probe: medir tiempo de arranque, loguear
-- [ ] 23.6: Commit: `fase(23): observability and health probes`
+- [x] 23.1: Request correlation: requestId en CADA log entry via pino child logger
+- [x] 23.2: Structured error logging con contexto (userId, sessionId, etc.)
+- [x] 23.3: Liveness probe: GET /health/live
+- [x] 23.4: Readiness probe: GET /health/ready (DB + job queue check)
+- [x] 23.5: Startup probe: medir tiempo de arranque, loguear
+- [x] 23.6: Commit: `fase(23): observability and health probes`
 
 ---
 
diff --git a/dist/api/middleware/errorHandler.js b/dist/api/middleware/errorHandler.js
index 08768b1..37edea8 100644
--- a/dist/api/middleware/errorHandler.js
+++ b/dist/api/middleware/errorHandler.js
@@ -51,10 +51,12 @@ class RateLimitError extends AppError {
 }
 exports.RateLimitError = RateLimitError;
 function globalErrorHandler(err, req, res, _next) {
-    const logger = req.log;
+    const authReq = req;
+    const logger = authReq.log;
+    const userId = authReq.user?.id;
     if (err instanceof AppError && err.isOperational) {
         if (logger) {
-            logger.warn({ err, statusCode: err.statusCode }, err.message);
+            logger.warn({ err, statusCode: err.statusCode, userId }, err.message);
         }
         const body = { error: err.message, code: err.code };
         if (err instanceof ValidationError && err.details !== undefined) {
@@ -64,7 +66,7 @@ function globalErrorHandler(err, req, res, _next) {
         return;
     }
     if (logger) {
-        logger.error({ err }, 'Unhandled error');
+        logger.error({ err, userId }, 'Unhandled error');
     }
     else {
         console.error('Unhandled error', err);
diff --git a/dist/main.js b/dist/main.js
index 757fc56..fbe0913 100644
--- a/dist/main.js
+++ b/dist/main.js
@@ -84,6 +84,8 @@ const ReportWorker_1 = require("./jobs/workers/ReportWorker");
 const server_1 = require("./api/server");
 const SocketGateway_1 = require("./realtime/SocketGateway");
 async function bootstrap() {
+    // Startup probe — measure total boot time
+    const startupAt = Date.now();
     // 1. Config
     const config = (0, Config_1.loadConfig)();
     // 2. Logger
@@ -208,7 +210,8 @@ async function bootstrap() {
     await new Promise((resolve) => {
         httpServer.listen(config.port, config.host, resolve);
     });
-    logger.info({ port: config.port, host: config.host }, 'ABE server ready');
+    const startupMs = Date.now() - startupAt;
+    logger.info({ port: config.port, host: config.host, startupMs }, 'ABE server ready');
     // 14. Graceful shutdown
     let shuttingDown = false;
     async function shutdown(signal) {
diff --git a/src/api/middleware/errorHandler.ts b/src/api/middleware/errorHandler.ts
index c2da710..c72d946 100644
--- a/src/api/middleware/errorHandler.ts
+++ b/src/api/middleware/errorHandler.ts
@@ -49,17 +49,27 @@ export class RateLimitError extends AppError {
   }
 }
 
+type ExtendedReq = Request & {
+  log?: {
+    warn(obj: Record<string, unknown>, msg: string): void;
+    error(obj: Record<string, unknown>, msg: string): void;
+  };
+  user?: { id: string; email: string; role: string };
+};
+
 export function globalErrorHandler(
   err: Error,
   req: Request,
   res: Response,
   _next: NextFunction,
 ): void {
-  const logger = (req as Request & { log?: { warn: Function; error: Function } }).log;
+  const authReq = req as ExtendedReq;
+  const logger = authReq.log;
+  const userId = authReq.user?.id;
 
   if (err instanceof AppError && err.isOperational) {
     if (logger) {
-      logger.warn({ err, statusCode: err.statusCode }, err.message);
+      logger.warn({ err, statusCode: err.statusCode, userId }, err.message);
     }
     const body: Record<string, unknown> = { error: err.message, code: err.code };
     if (err instanceof ValidationError && err.details !== undefined) {
@@ -70,7 +80,7 @@ export function globalErrorHandler(
   }
 
   if (logger) {
-    logger.error({ err }, 'Unhandled error');
+    logger.error({ err, userId }, 'Unhandled error');
   } else {
     console.error('Unhandled error', err);
   }
diff --git a/src/main.ts b/src/main.ts
index ce22291..ef85441 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -93,6 +93,9 @@ import { createServer } from './api/server';
 import { SocketGateway } from './realtime/SocketGateway';
 
 async function bootstrap(): Promise<void> {
+  // Startup probe — measure total boot time
+  const startupAt = Date.now();
+
   // 1. Config
   const config = loadConfig();
 
@@ -247,7 +250,8 @@ async function bootstrap(): Promise<void> {
   await new Promise<void>((resolve) => {
     httpServer.listen(config.port, config.host, resolve);
   });
-  logger.info({ port: config.port, host: config.host }, 'ABE server ready');
+  const startupMs = Date.now() - startupAt;
+  logger.info({ port: config.port, host: config.host, startupMs }, 'ABE server ready');
 
   // 14. Graceful shutdown
   let shuttingDown = false;