[Amber] Fix: [Amber] add opus-4.5 to the list of models available to ACP users. (#398)

## Automated Fix by Amber Agent

This PR addresses issue #397 using the Amber background agent.

### Changes Summary
- **Action Type:** auto-fix
- **Commit:** af0fcd8
- **Triggered by:** Issue label/command

### Pre-merge Checklist
- [ ] All linters pass
- [ ] All tests pass
- [ ] Changes follow project conventions (CLAUDE.md)
- [ ] No scope creep beyond issue description

### Reviewer Notes
This PR was automatically generated. Please review:
1. Code quality and adherence to standards
2. Test coverage for changes
3. No unintended side effects

---
🤖 Generated with [Amber Background
Agent](https://github.com/ambient-code/platform/blob/main/docs/amber-automation.md)

Closes #397

Co-authored-by: Amber Agent <[email protected]>
Co-authored-by: Claude <[email protected]>

Author: 3 people

components/frontend/src/app/projects/[name]/sessions/new/model-configuration.tsx

@@ -7,6 +7,7 @@ import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@
 
 const models = [
   { value: "claude-sonnet-4-5", label: "Claude Sonnet 4.5" },
+  { value: "claude-opus-4-5", label: "Claude Opus 4.5" },
   { value: "claude-opus-4-1", label: "Claude Opus 4.1" },
   { value: "claude-haiku-4-5", label: "Claude Haiku 4.5" },
 ];

components/frontend/src/components/create-session-dialog.tsx

@@ -40,6 +40,7 @@ import { successToast, errorToast } from "@/hooks/use-toast";
 
 const models = [
   { value: "claude-sonnet-4-5", label: "Claude Sonnet 4.5" },
+  { value: "claude-opus-4-5", label: "Claude Opus 4.5" },
   { value: "claude-opus-4-1", label: "Claude Opus 4.1" },
   { value: "claude-haiku-4-5", label: "Claude Haiku 4.5" },
 ];

components/runners/claude-code-runner/tests/test_model_mapping.py

@@ -20,6 +20,12 @@
 class TestMapToVertexModel:
     """Test suite for _map_to_vertex_model method"""
 
+    def test_map_opus_4_5(self):
+        """Test mapping for Claude Opus 4.5"""
+        adapter = ClaudeCodeAdapter()
+        result = adapter._map_to_vertex_model('claude-opus-4-5')
+        assert result == 'claude-opus-4-5@20251101'
+
     def test_map_opus_4_1(self):
         """Test mapping for Claude Opus 4.1"""
         adapter = ClaudeCodeAdapter()
@@ -86,14 +92,16 @@ def test_all_frontend_models_have_mapping(self):
         # These are the exact model values from the frontend dropdown
         frontend_models = [
             'claude-sonnet-4-5',
-            'claude-haiku-4-5',
+            'claude-opus-4-5',
             'claude-opus-4-1',
+            'claude-haiku-4-5',
         ]
 
         expected_mappings = {
             'claude-sonnet-4-5': 'claude-sonnet-4-5@20250929',
-            'claude-haiku-4-5': 'claude-haiku-4-5@20251001',
+            'claude-opus-4-5': 'claude-opus-4-5@20251101',
             'claude-opus-4-1': 'claude-opus-4-1@20250805',
+            'claude-haiku-4-5': 'claude-haiku-4-5@20251001',
         }
 
         for model in frontend_models:
@@ -105,7 +113,7 @@ def test_mapping_includes_version_date(self):
         """Test that all mapped models include version dates"""
         adapter = ClaudeCodeAdapter()
 
-        models = ['claude-opus-4-1', 'claude-sonnet-4-5', 'claude-haiku-4-5']
+        models = ['claude-opus-4-5', 'claude-opus-4-1', 'claude-sonnet-4-5', 'claude-haiku-4-5']
 
         for model in models:
             result = adapter._map_to_vertex_model(model)
@@ -152,6 +160,7 @@ def test_mapping_matches_available_vertex_models(self):
 
         # Expected Vertex AI model ID format: model-name@YYYYMMDD
         models_to_test = [
+            ('claude-opus-4-5', 'claude-opus-4-5@20251101'),
             ('claude-opus-4-1', 'claude-opus-4-1@20250805'),
             ('claude-sonnet-4-5', 'claude-sonnet-4-5@20250929'),
             ('claude-haiku-4-5', 'claude-haiku-4-5@20251001'),
@@ -169,8 +178,9 @@ def test_ui_to_vertex_round_trip(self):
         # Simulate user selecting from UI dropdown
         ui_selections = [
             'claude-sonnet-4-5',  # User selects Sonnet 4.5
-            'claude-haiku-4-5',   # User selects Haiku 4.5
+            'claude-opus-4-5',    # User selects Opus 4.5
             'claude-opus-4-1',    # User selects Opus 4.1
+            'claude-haiku-4-5',   # User selects Haiku 4.5
         ]
 
         for selection in ui_selections:
@@ -190,10 +200,15 @@ def test_end_to_end_vertex_mapping_flow(self):
 
         # Simulate complete flow for each model
         test_scenarios = [
+            {
+                'ui_selection': 'claude-opus-4-5',
+                'expected_vertex_id': 'claude-opus-4-5@20251101',
+                'description': 'Latest Opus model',
+            },
             {
                 'ui_selection': 'claude-opus-4-1',
                 'expected_vertex_id': 'claude-opus-4-1@20250805',
-                'description': 'Most capable model',
+                'description': 'Previous Opus model',
             },
             {
                 'ui_selection': 'claude-sonnet-4-5',
@@ -231,10 +246,11 @@ def test_model_ordering_consistency(self):
         """Test that model ordering is consistent between frontend and backend"""
         adapter = ClaudeCodeAdapter()
 
-        # Expected ordering: Opus (most capable) → Sonnet (balanced) → Haiku (fastest)
+        # Expected ordering: Sonnet → Opus 4.5 → Opus 4.1 → Haiku (matches frontend dropdown)
         expected_order = [
-            'claude-opus-4-1',
             'claude-sonnet-4-5',
+            'claude-opus-4-5',
+            'claude-opus-4-1',
             'claude-haiku-4-5',
         ]
 
@@ -243,7 +259,8 @@ def test_model_ordering_consistency(self):
             vertex_id = adapter._map_to_vertex_model(model)
             assert '@' in vertex_id, f"Model {model} should map to valid Vertex AI ID"
 
-        # Verify ordering matches capability hierarchy
-        assert expected_order[0] == 'claude-opus-4-1'  # Most capable first
-        assert expected_order[1] == 'claude-sonnet-4-5'  # Balanced second
-        assert expected_order[2] == 'claude-haiku-4-5'  # Fastest third
+        # Verify ordering matches frontend dropdown
+        assert expected_order[0] == 'claude-sonnet-4-5'  # Balanced (default)
+        assert expected_order[1] == 'claude-opus-4-5'  # Latest Opus
+        assert expected_order[2] == 'claude-opus-4-1'  # Previous Opus
+        assert expected_order[3] == 'claude-haiku-4-5'  # Fastest

components/runners/claude-code-runner/wrapper.py

@@ -748,6 +748,7 @@ def _map_to_vertex_model(self, model: str) -> str:
         # Model mapping from Anthropic API to Vertex AI
         # Reference: https://cloud.google.com/vertex-ai/generative-ai/docs/partner-models/use-claude
         model_map = {
+            'claude-opus-4-5': 'claude-opus-4-5@20251101',
             'claude-opus-4-1': 'claude-opus-4-1@20250805',
             'claude-sonnet-4-5': 'claude-sonnet-4-5@20250929',
             'claude-haiku-4-5': 'claude-haiku-4-5@20251001',