Validate dimensions in the daemon /generate path

The one-shot CLI already rejects non-multiple-of-8 width/height up front, but
the daemon passed them straight through, so an odd dimension over HTTP produced
a downstream 500 or garbled output instead of a clear error. Add the same %8
check to /generate, returning 400 with a specific message. Also correct the
generate.py scope comment: the registry now holds SDXL-architecture fine-tunes,
not just SDXL base.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

2 files changed, 14 insertions, 6 deletions

diff --git a/generate.py b/generate.py
index 95b2dd7..b6c0fb8 100644
--- a/generate.py
+++ b/generate.py
@@ -10,10 +10,11 @@
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU General Public License for more details.
 
-# Local SDXL-base image generation for Intel Arc B580 (XPU backend).
-# Bounded scope by design: SDXL base, single 1024x1024 image, no refiner,
-# no Flux, no batching. This is what fits comfortably in 12GB VRAM once the
-# fp32 VAE upcast is removed via the fp16-fix VAE. See README.md for limits.
+# Local SDXL image generation for Intel Arc B580 (XPU backend).
+# Bounded scope by design: SDXL-architecture models (see MODELS registry),
+# single 1024x1024 image, no refiner, no Flux, no batching. This is what fits
+# comfortably in 12GB VRAM once the fp32 VAE upcast is removed via the fp16-fix
+# VAE. See README.md for limits.
 
 import argparse
 import sys
diff --git a/server.py b/server.py
index f3be9e5..f289f64 100644
--- a/server.py
+++ b/server.py
@@ -84,6 +84,13 @@ class Handler(BaseHTTPRequestHandler):
             return
 
         if self.path == "/generate":
+            width = int(data.get("width", 1024))
+            height = int(data.get("height", 1024))
+            if width % 8 or height % 8:
+                # Match the one-shot CLI: reject bad dims up front with a clear
+                # client error instead of a downstream 500 or garbled output.
+                self._json(400, {"error": "width and height must be multiples of 8"})
+                return
             try:
                 image, elapsed = generate.generate(
                     STATE["pipe"],
@@ -92,8 +99,8 @@ class Handler(BaseHTTPRequestHandler):
                     int(data.get("steps", 25)),
                     float(data.get("guidance", 7.0)),
                     data.get("seed"),
-                    int(data.get("width", 1024)),
-                    int(data.get("height", 1024)),
+                    width,
+                    height,
                 )
             except torch.OutOfMemoryError:
                 torch.xpu.empty_cache()