diff --git a/.aiox-core/core/orchestration/context-manager.js b/.aiox-core/core/orchestration/context-manager.js
index 893616941e..af2b743496 100644
--- a/.aiox-core/core/orchestration/context-manager.js
+++ b/.aiox-core/core/orchestration/context-manager.js
@@ -16,6 +16,31 @@
 
 const fs = require('fs-extra');
 const path = require('path');
+const { isPlainObject } = require('../config/merge-utils');
+
+function mergeMetadata(target, source) {
+  const base = isPlainObject(target) ? target : {};
+
+  if (!isPlainObject(source)) {
+    return { ...base };
+  }
+
+  const result = { ...base };
+
+  for (const [key, value] of Object.entries(source)) {
+    result[key] = isPlainObject(value) && isPlainObject(result[key])
+      ? mergeMetadata(result[key], value)
+      : value;
+  }
+
+  return result;
+}
+
+function describeMetadataInput(value) {
+  if (value === null) return 'null';
+  if (Array.isArray(value)) return 'array';
+  return typeof value;
+}
 
 /**
  * Manages workflow execution context and state persistence
@@ -224,8 +249,14 @@ class ContextManager {
    * @param {Object} metadata - Metadata to merge
    */
   async updateMetadata(metadata) {
+    if (!isPlainObject(metadata)) {
+      throw new TypeError(
+        `updateMetadata expects a plain object, received: ${describeMetadataInput(metadata)}`,
+      );
+    }
+
     const state = await this.loadState();
-    state.metadata = { ...state.metadata, ...metadata };
+    state.metadata = mergeMetadata(state.metadata, metadata);
     this._stateCache = state;
     await this._saveState();
   }
diff --git a/.aiox-core/install-manifest.yaml b/.aiox-core/install-manifest.yaml
index e61ee0b297..d8fad22563 100644
--- a/.aiox-core/install-manifest.yaml
+++ b/.aiox-core/install-manifest.yaml
@@ -8,7 +8,7 @@
 # - File types for categorization
 #
 version: 5.1.15
-generated_at: "2026-05-08T04:49:28.006Z"
+generated_at: "2026-05-08T05:14:31.637Z"
 generator: scripts/generate-install-manifest.js
 file_count: 1111
 files:
@@ -845,9 +845,9 @@ files:
     type: core
     size: 12722
   - path: core/orchestration/context-manager.js
-    hash: sha256:7bf273723a2c08cb84e670b9d4c55aacec51819b1fbd5f3b0c46c4ccfa2ec192
+    hash: sha256:b6ed0e4eb069558998f95ab0c68fa040b1b8c2aab74ab44e26ab682fe9e247b4
     type: core
-    size: 16842
+    size: 17620
   - path: core/orchestration/dashboard-integration.js
     hash: sha256:8f2dd7d3885a9eaf58957505d312923e149f2771ae3ca0cda879631683f826c9
     type: core
diff --git a/tests/core/orchestration/context-manager.test.js b/tests/core/orchestration/context-manager.test.js
index 2d31f5d2ea..5326839975 100644
--- a/tests/core/orchestration/context-manager.test.js
+++ b/tests/core/orchestration/context-manager.test.js
@@ -567,6 +567,58 @@ describe('ContextManager', () => {
       expect(manager._stateCache.metadata.projectRoot).toBe('/outro/caminho');
     });
 
+    test('preserva metadados aninhados ao aplicar merge profundo', async () => {
+      await manager.updateMetadata({
+        observability: {
+          attempts: {
+            total: 1,
+            lastPhase: 'planning',
+          },
+          tags: ['initial'],
+          nullable: 'keep',
+        },
+      });
+
+      await manager.updateMetadata({
+        observability: {
+          attempts: {
+            failed: 1,
+          },
+          lastError: {
+            code: 'EACCES',
+          },
+          tags: ['latest'],
+          nullable: null,
+        },
+      });
+
+      expect(manager._stateCache.metadata.observability).toEqual({
+        attempts: {
+          total: 1,
+          lastPhase: 'planning',
+          failed: 1,
+        },
+        lastError: {
+          code: 'EACCES',
+        },
+        tags: ['latest'],
+        nullable: null,
+      });
+    });
+
+    test.each([
+      ['null', null],
+      ['undefined', undefined],
+      ['array', []],
+      ['string', 'metadata'],
+    ])('rejeita metadata inválido: %s', async (_label, invalidMetadata) => {
+      await expect(manager.updateMetadata(invalidMetadata)).rejects.toThrow(
+        'updateMetadata expects a plain object',
+      );
+
+      expect(fs.writeJson).not.toHaveBeenCalled();
+    });
+
     test('persiste estado no disco', async () => {
       await manager.updateMetadata({ foo: 'bar' });