descrip length check and fix

build.py

@@ -41,6 +41,8 @@ EXCLUDE_DIRS = {"__pycache__", ".git"}
 EXCLUDE_NAMES = {".DS_Store"}
 EXCLUDE_SUFFIXES = {".pyc", ".pyo"}
 FIXED_DATE = (2026, 1, 1, 0, 0, 0)  # stable timestamp for reproducible archives
+MAX_DESCRIPTION = 500  # plugin-marketplace cap: plugin.json "description" must be UNDER this
+                       # (it has silently regressed past the limit before — fail the build now)
 
 _KEY_RE = re.compile(r'(DEFAULT_KEY\s*=\s*")([0-9a-fA-F]{16,})(")')
 
@@ -102,7 +104,14 @@ def main(argv: list[str] | None = None) -> int:
         return 1
 
     manifest_path = SRC / ".claude-plugin" / "plugin.json"
-    version = json.loads(manifest_path.read_text(encoding="utf-8"))["version"]
+    manifest = json.loads(manifest_path.read_text(encoding="utf-8"))
+    version = manifest["version"]
+    desc = manifest.get("description", "")
+    if len(desc) >= MAX_DESCRIPTION:
+        print(f"build: plugin description is {len(desc)} chars — must be under "
+              f"{MAX_DESCRIPTION} (marketplace cap). Trim \"description\" in {MANIFEST}.",
+              file=sys.stderr)
+        return 1
     files = included_files()
     arcnames = {p.relative_to(SRC).as_posix() for p in files}
     if MANIFEST not in arcnames: