diff --git a/src/scripts/update_platform_envs.py b/src/scripts/update_platform_envs.py
index bb61078..635b8ce 100644
--- a/src/scripts/update_platform_envs.py
+++ b/src/scripts/update_platform_envs.py
@@ -74,12 +74,19 @@ def copy_common_workspace(target: Path) -> None:
     (target / "projects" / ".gitkeep").touch(exist_ok=True)
 
 
+def copy_platform_readme(platform: str, target: Path) -> None:
+    src = ADAPTER_ROOT / platform / "README.md"
+    if not src.exists():
+        raise FileNotFoundError(src)
+    shutil.copy2(src, target / "README.md")
+
+
 def build_antigravity() -> Path:
     target = REPO_ROOT / "antigravity"
     reset_dir(target)
     copy_common_workspace(target)
     copy_dir(ADAPTER_ROOT / "antigravity" / "agent", target / ".agent")
-    copy_file("platform_adapters/antigravity/README.md", target)
+    copy_platform_readme("antigravity", target)
     return target
 
 
@@ -89,7 +96,7 @@ def build_codex() -> Path:
     copy_common_workspace(target)
     copy_dir(ADAPTER_ROOT / "codex", target / ".codex")
     copy_dir(ADAPTER_ROOT / "antigravity" / "agent" / "skills", target / ".codex" / "skills")
-    copy_file("platform_adapters/codex/README.md", target)
+    copy_platform_readme("codex", target)
     return target
 
 
@@ -98,7 +105,7 @@ def build_opencode() -> Path:
     reset_dir(target)
     copy_common_workspace(target)
     copy_dir(ADAPTER_ROOT / "opencode", target / ".opencode")
-    copy_file("platform_adapters/opencode/README.md", target)
+    copy_platform_readme("opencode", target)
     return target
 
 
@@ -107,7 +114,7 @@ def build_claude_code() -> Path:
     reset_dir(target)
     copy_common_workspace(target)
     copy_dir(ADAPTER_ROOT / "claude-code", target / ".claude")
-    copy_file("platform_adapters/claude-code/README.md", target)
+    copy_platform_readme("claude-code", target)
     return target
 
 
@@ -116,7 +123,7 @@ def build_gemini_cli() -> Path:
     reset_dir(target)
     copy_common_workspace(target)
     copy_dir(ADAPTER_ROOT / "gemini-cli", target / ".gemini")
-    copy_file("platform_adapters/gemini-cli/README.md", target)
+    copy_platform_readme("gemini-cli", target)
     return target