diff --git a/deploy/README.md b/deploy/README.md
index 4a4066e..48c21bd 100644
--- a/deploy/README.md
+++ b/deploy/README.md
@@ -204,7 +204,11 @@ new image. Migrations always run before the new API starts, and only when an ope
 ### Size
 
 The platform-only image is about 378 MB: the Debian slim Node base (about 230 MB), production
-dependencies (about 141 MB), and built outputs (about 6 MB).
+dependencies (about 141 MB), and built outputs (about 6 MB). A rebuild that reuses a warm pnpm store
+cache can come out about 21 MB larger. When esbuild's install script runs, it hard-links its
+`bin/esbuild` to the native binary it ships beside it; when pnpm restores esbuild from the store's
+cached post-install state instead, that file is a second full copy. Both are esbuild, one of the
+unused tools below.
 
 About 57 MB of the production dependencies are development tools that no runtime code imports:
 `vitest`, `vite`, `drizzle-kit`, `tsx`, `esbuild`, and their native bindings. They arrive as