diff --git a/Dockerfile b/Dockerfile
index 2ba17c2..1a68ca6 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -44,18 +44,26 @@ COPY --from=builder /app/src/generated ./src/generated
 
 # Install runtime deps needed for migrations + seed. The Next.js standalone
 # bundle covers the app itself, but the seed script (prisma/seed-dow.ts) is
-# a separate .ts file executed via tsx and needs its own module graph:
+# a separate .ts file executed via tsx.
+#
+# tsx is installed GLOBALLY (lives at /usr/local/bin/tsx, on PATH
+# unconditionally). Installing it locally via `npm install --no-save tsx`
+# doesn't work reliably here because Next.js's standalone node_modules
+# layout aggressively reshuffles its own tree — the tsx binary was
+# repeatedly going missing from node_modules/.bin after what npm reported
+# as a successful install. Global install sidesteps that entirely.
+#
+# Other deps are local (alongside the standalone tree):
 #   prisma      — the migrate-deploy CLI
 #   dotenv      — prisma.config.ts imports dotenv/config
-#   tsx         — runs the seed without an ahead-of-time compile
 #   @prisma/adapter-pg — the driver the seed instantiates directly
 #   bcryptjs    — the seed hashes the admin's temp password
-RUN npm install --no-save \
-    prisma@7.4.2 \
-    dotenv@17.3.1 \
-    tsx@4 \
-    @prisma/adapter-pg@7.4.2 \
-    bcryptjs@3
+RUN npm install -g tsx@4 && \
+    npm install --no-save \
+      prisma@7.4.2 \
+      dotenv@17.3.1 \
+      @prisma/adapter-pg@7.4.2 \
+      bcryptjs@3
 
 # Create uploads directories for media storage
 RUN mkdir -p /data/uploads && chown nextjs:nodejs /data/uploads