diff --git a/examples/node-yarn-workspaces-nested/.gitignore b/examples/node-yarn-workspaces-nested/.gitignore
new file mode 100644
index 000000000..6fb8e236f
--- /dev/null
+++ b/examples/node-yarn-workspaces-nested/.gitignore
@@ -0,0 +1,4 @@
+node_modules
+.pnp.cjs
+.pnp.loader.mjs
+.yarn/install-state.gz
diff --git a/examples/node-yarn-workspaces-nested/.yarnrc.yml b/examples/node-yarn-workspaces-nested/.yarnrc.yml
new file mode 100644
index 000000000..09b10123b
--- /dev/null
+++ b/examples/node-yarn-workspaces-nested/.yarnrc.yml
@@ -0,0 +1 @@
+nodeLinker: pnp
diff --git a/examples/node-yarn-workspaces-nested/README.md b/examples/node-yarn-workspaces-nested/README.md
new file mode 100644
index 000000000..7c93e85be
--- /dev/null
+++ b/examples/node-yarn-workspaces-nested/README.md
@@ -0,0 +1,36 @@
+# node-yarn-workspaces-nested
+
+Reproduces [#463](https://github.com/railwayapp/railpack/issues/463): a Yarn
+Berry monorepo with a deeply-nested workspace package causes a phantom duplicate
+directory inside the container, making `yarn install` fail.
+
+## Structure
+
+The workspace glob is `packages/**/*` (recursive), with a package at
+`packages/prisma/timescaledb/`. The intermediate directory `packages/prisma/`
+happens to be named `prisma`, which matches the `prisma` entry in
+`SupportingInstallFiles`.
+
+## The bug
+
+`SupportingInstallFiles` returns both:
+
+- `packages/prisma/timescaledb/package.json` (matched as a file)
+- `packages/prisma` (matched as a directory named `prisma`)
+
+This produces two copy commands in the build plan:
+
+1. `copy packages/prisma/timescaledb/package.json` → creates
+   `/app/packages/prisma/timescaledb/`
+2. `copy packages/prisma → packages/prisma` → because BuildKit uses
+   `CopyDirContentsOnly: false`, the directory `prisma/` is placed *inside*
+   `/app/packages/prisma/`, creating the phantom
+   `/app/packages/prisma/prisma/timescaledb/`
+
+Yarn then sees two workspaces with the same name and fails:
+
+```
+Internal Error: Duplicate workspace name @wildmetrics/prisma-timescale:
+  /app/packages/prisma/timescaledb conflicts with
+  /app/packages/prisma/prisma/timescaledb
+```
diff --git a/examples/node-yarn-workspaces-nested/index.js b/examples/node-yarn-workspaces-nested/index.js
new file mode 100644
index 000000000..9cb2f05b3
--- /dev/null
+++ b/examples/node-yarn-workspaces-nested/index.js
@@ -0,0 +1,2 @@
+import { message } from "@wildmetrics/prisma-timescale";
+console.log(message);
diff --git a/examples/node-yarn-workspaces-nested/package.json b/examples/node-yarn-workspaces-nested/package.json
new file mode 100644
index 000000000..af3d727b9
--- /dev/null
+++ b/examples/node-yarn-workspaces-nested/package.json
@@ -0,0 +1,16 @@
+{
+  "name": "node-yarn-workspaces-nested",
+  "version": "1.0.0",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "start": "node index.js"
+  },
+  "workspaces": [
+    "packages/**/*"
+  ],
+  "dependencies": {
+    "@wildmetrics/prisma-timescale": "workspace:*"
+  },
+  "packageManager": "yarn@4.5.3"
+}
diff --git a/examples/node-yarn-workspaces-nested/packages/prisma/timescaledb/index.js b/examples/node-yarn-workspaces-nested/packages/prisma/timescaledb/index.js
new file mode 100644
index 000000000..20ced2518
--- /dev/null
+++ b/examples/node-yarn-workspaces-nested/packages/prisma/timescaledb/index.js
@@ -0,0 +1 @@
+export const message = "hello from timescaledb package";
diff --git a/examples/node-yarn-workspaces-nested/packages/prisma/timescaledb/package.json b/examples/node-yarn-workspaces-nested/packages/prisma/timescaledb/package.json
new file mode 100644
index 000000000..8655a8c63
--- /dev/null
+++ b/examples/node-yarn-workspaces-nested/packages/prisma/timescaledb/package.json
@@ -0,0 +1,6 @@
+{
+  "name": "@wildmetrics/prisma-timescale",
+  "version": "1.0.0",
+  "type": "module",
+  "main": "index.js"
+}
diff --git a/examples/node-yarn-workspaces-nested/test.json b/examples/node-yarn-workspaces-nested/test.json
new file mode 100644
index 000000000..3b1e5be2b
--- /dev/null
+++ b/examples/node-yarn-workspaces-nested/test.json
@@ -0,0 +1,5 @@
+[
+  {
+    "expectedOutput": "hello from timescaledb package"
+  }
+]
diff --git a/examples/node-yarn-workspaces-nested/yarn.lock b/examples/node-yarn-workspaces-nested/yarn.lock
new file mode 100644
index 000000000..995128ef2
--- /dev/null
+++ b/examples/node-yarn-workspaces-nested/yarn.lock
@@ -0,0 +1,20 @@
+# This file is generated by running "yarn install" inside your project.
+# Manual changes might be lost - proceed with caution!
+
+__metadata:
+  version: 8
+  cacheKey: 10c0
+
+"@wildmetrics/prisma-timescale@workspace:*, @wildmetrics/prisma-timescale@workspace:packages/prisma/timescaledb":
+  version: 0.0.0-use.local
+  resolution: "@wildmetrics/prisma-timescale@workspace:packages/prisma/timescaledb"
+  languageName: unknown
+  linkType: soft
+
+"node-yarn-workspaces-nested@workspace:.":
+  version: 0.0.0-use.local
+  resolution: "node-yarn-workspaces-nested@workspace:."
+  dependencies:
+    "@wildmetrics/prisma-timescale": "workspace:*"
+  languageName: unknown
+  linkType: soft