feat(image): add Nano Banana 2.1 (BELUGA), retire NARWHAL from the NANO_BANANA_2 nickname

agent/models.json

@@ -55,7 +55,8 @@
   },
   "image_models": {
     "NANO_BANANA_PRO": "GEM_PIX_2",
-    "NANO_BANANA_2": "NARWHAL",
+    "NANO_BANANA_2_1": "BELUGA",
+    "NANO_BANANA_2": "BELUGA",
     "NANO_BANANA_2_LITE": "HARBOR_SEAL"
   },
   "default_image_model": "NANO_BANANA_PRO",

agent/services/flow_batch.py

@@ -59,13 +59,22 @@
 #: ids are accepted by ``resolve_image_model`` instead of being silently
 #: replaced by the default, so callers can opt into a newly exposed model
 #: before Flow Kit itself ships another release.
-IMAGE_MODELS = {"GEM_PIX_2", "NARWHAL", "HARBOR_SEAL"}
+#:
+#: BELUGA is Nano Banana 2.1 (the UI's `beluga_display`); the THINKING
+#: variants are values 37-39 of the same enum in the Flow bundle. Banana 2
+#: (`NARWHAL`) has answered `[5]` NOT_FOUND in every project since early
+#: October 2026, so the NANO_BANANA_2 nickname now lands on its successor.
+IMAGE_MODELS = {
+    "GEM_PIX_2", "NARWHAL", "HARBOR_SEAL",
+    "BELUGA", "BELUGA_THINKING_LOW", "BELUGA_THINKING_MED", "BELUGA_THINKING_HIGH",
+}
 IMAGE_MODEL = "GEM_PIX_2"
 
 #: Friendly aliases. Exact Flow wire ids work too.
 IMAGE_MODEL_BY_NICKNAME = {
     "NANO_BANANA_PRO": "GEM_PIX_2",
-    "NANO_BANANA_2": "NARWHAL",
+    "NANO_BANANA_2_1": "BELUGA",
+    "NANO_BANANA_2": "BELUGA",
     "NANO_BANANA_2_LITE": "HARBOR_SEAL",
     "NANO_BANANA_LITE": "HARBOR_SEAL",
 }

skills/fk-change-model.md

@@ -29,9 +29,11 @@ So changing a Landscape vs Portrait key has **no effect** on the batch path —
 only the quality tier survives the fold. `r2v` and `start_end` keys are moot
 there too: both are unported.
 
-Image models are unaffected: `GEM_PIX_2` (Nano Banana Pro) and `NARWHAL`
-(Banana 2) are both accepted, and `default_image_model` in `models.json` picks
-which nickname is used.
+Image models are unaffected: `GEM_PIX_2` (Nano Banana Pro), `BELUGA`
+(Nano Banana 2.1, plus `BELUGA_THINKING_LOW/MED/HIGH`) and `HARBOR_SEAL`
+(2 Lite) are accepted, and `default_image_model` in `models.json` picks which
+nickname is used. `NARWHAL` (Banana 2) answers `[5]` NOT_FOUND since October
+2026; the `NANO_BANANA_2` nickname now maps to `BELUGA`.
 
 ## Step 1: Show Current Models
 
@@ -57,7 +59,9 @@ Display in a readable table:
 | Key | Model |
 |-----|-------|
 | NANO_BANANA_PRO | `GEM_PIX_2` |
-| NANO_BANANA_2 | `NARWHAL` |
+| NANO_BANANA_2_1 | `BELUGA` |
+| NANO_BANANA_2 | `BELUGA` (was `NARWHAL`, retired) |
+| NANO_BANANA_2_LITE | `HARBOR_SEAL` |
 
 ### Upscale Models
 
@@ -82,7 +86,8 @@ After user picks, apply the matching preset from the Quick Switch Presets sectio
 **For image model:**
 Use `AskUserQuestion` with options:
 - label: "GEM_PIX_2 (Recommended)", description: "Gemini Pix 2 · current default"
-- label: "NARWHAL", description: "Alternative image model"
+- label: "BELUGA", description: "Nano Banana 2.1"
+- label: "HARBOR_SEAL", description: "Nano Banana 2 Lite"
 
 ## Step 3: Change a Model (Manual)
 
@@ -231,7 +236,10 @@ curl -s -X PATCH http://127.0.0.1:8100/api/models \
 | Key | Description |
 |-----|-------------|
 | `GEM_PIX_2` | Gemini Pix 2 (current default) |
-| `NARWHAL` | Narwhal model |
+| `BELUGA` | Nano Banana 2.1 |
+| `BELUGA_THINKING_LOW` / `_MED` / `_HIGH` | Nano Banana 2.1 with thinking |
+| `HARBOR_SEAL` | Nano Banana 2 Lite |
+| `NARWHAL` | Nano Banana 2 — retired, answers `[5]` NOT_FOUND |
 
 ### Upscale
 | Key | Description |

tests/unit/test_flow_batch.py

@@ -330,11 +330,16 @@ def test_an_unknown_aspect_name_raises_rather_than_defaulting(self):
 
     def test_nicknames_resolve_to_wire_names(self):
         assert fb.resolve_image_model("NANO_BANANA_PRO") == "GEM_PIX_2"
-        assert fb.resolve_image_model("NANO_BANANA_2") == "NARWHAL"
+        assert fb.resolve_image_model("NANO_BANANA_2_1") == "BELUGA"
         assert fb.resolve_image_model("NANO_BANANA_2_LITE") == "HARBOR_SEAL"
 
+    def test_nano_banana_2_lands_on_its_successor_not_the_retired_narwhal(self):
+        assert fb.resolve_image_model("NANO_BANANA_2") == "BELUGA"
+
     def test_wire_names_and_future_model_ids_pass_through(self):
         assert fb.resolve_image_model("NARWHAL") == "NARWHAL"
+        assert fb.resolve_image_model("BELUGA") == "BELUGA"
+        assert fb.resolve_image_model("beluga_thinking_high") == "BELUGA_THINKING_HIGH"
         assert fb.resolve_image_model("harbor_seal") == "HARBOR_SEAL"
         assert fb.resolve_image_model("FUTURE_BANANA_3") == "FUTURE_BANANA_3"