Install Pillow so capture_view actually downscales

README.md

@@ -34,8 +34,8 @@ Pick Codex when you want the safety controls.
 pip install -r requirements.txt
 ```
 
-Both dependencies were already installed on this machine; the file pins the
-versions this was verified against.
+The file pins the versions this was verified against. Pillow is what
+`capture_view` uses to downscale its render; without it you get the full plot.
 
 ## Running it
 

requirements.txt

@@ -4,5 +4,9 @@
 # The pins record what the server was verified against: pywin32 live with
 # AutoCAD on 2026-07-30; mcp raised from 1.27.1 to 1.28.1 on 2026-09-21 to
 # clear three published advisories, checked by tests/test_assembled_server.py.
+# Pillow is what lets capture_view downscale its render
+# (tests/test_shrink_png.py); 12.3.0 is clear of the advisories open
+# against 12.2.0.
 mcp==1.28.1
 pywin32==311
+Pillow==12.3.0

tests/test_shrink_png.py

@@ -0,0 +1,66 @@
+"""capture_view downscales its render with Pillow.
+
+tools._shrink_png is what keeps the plotted PNG cheap for a model to look at.
+Without Pillow it quietly returns the file at full plot size, so the input PNG
+here is written by hand (no Pillow needed) and the tests fail if nothing shrank.
+
+    python -m unittest discover -s tests -t .
+"""
+
+import os
+import struct
+import tempfile
+import unittest
+import zlib
+from pathlib import Path
+
+# Must be in place before config is first imported, or that import writes a
+# .secret file into the source tree.
+os.environ.setdefault("ACAD_MCP_SECRET_PATH", "unit-test-secret")
+
+import tools  # noqa: E402
+
+
+def write_png(path: Path, width: int, height: int) -> None:
+    """A plain 8-bit grayscale PNG, built with zlib alone."""
+
+    def chunk(kind: bytes, data: bytes) -> bytes:
+        crc = zlib.crc32(kind + data) & 0xFFFFFFFF
+        return struct.pack(">I", len(data)) + kind + data + struct.pack(">I", crc)
+
+    row = b"\x00" + bytes(x % 256 for x in range(width))
+    path.write_bytes(
+        b"\x89PNG\r\n\x1a\n"
+        + chunk(b"IHDR", struct.pack(">IIBBBBB", width, height, 8, 0, 0, 0, 0))
+        + chunk(b"IDAT", zlib.compress(row * height))
+        + chunk(b"IEND", b"")
+    )
+
+
+def png_size(data: bytes) -> tuple[int, int]:
+    if data[:8] != b"\x89PNG\r\n\x1a\n":
+        raise AssertionError("not a PNG")
+    return struct.unpack(">II", data[16:24])
+
+
+class ShrinkPng(unittest.TestCase):
+    def setUp(self):
+        scratch = tempfile.TemporaryDirectory()
+        self.addCleanup(scratch.cleanup)
+        self.png = Path(scratch.name) / "view.png"
+
+    def test_large_render_comes_back_at_the_limit(self):
+        write_png(self.png, 2400, 1600)
+        data, dimensions = tools._shrink_png(self.png, 1100)
+        self.assertEqual(png_size(data), (1100, 733))
+        self.assertEqual(dimensions, "1100x733, rendered at 2400x1600")
+
+    def test_small_render_keeps_its_size(self):
+        write_png(self.png, 800, 600)
+        data, dimensions = tools._shrink_png(self.png, 1100)
+        self.assertEqual(png_size(data), (800, 600))
+        self.assertEqual(dimensions, "800x600")
+
+
+if __name__ == "__main__":
+    unittest.main()