diff --git a/AGENTS.md b/AGENTS.md
index 8d83632..5417b5a 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -294,13 +294,23 @@ upstream bumps.
 **The size gate is not a substitute for naming the residue.** It carries
 ~225 MB of deliberate margin, so v1.9.1 shipped +131 MB of pure build
 residue — 110 MB of it npm's own download cache under `/root/.npm`, the
-rest foreign platform packages — and stayed green. Two named assertions
-now cover exactly that: no foreign npm-11 platform packages beyond the
-host arch (`@esbuild/*`, `@mariozechner/clipboard-*`), and no
-`/root/.npm` in the image. Note the second one refuses to run as
-non-root: `test ! -d /root/.npm` on mode-700 `/root` would otherwise
-pass for the wrong reason, which is the failure shape to watch for in
-any assertion about a path you may not be able to read.
+rest foreign platform packages — and stayed green. Four named assertions
+now cover that ground: no foreign npm-11 platform packages beyond the
+host arch (`@esbuild/*`, `@mariozechner/clipboard-*`), no `/root/.npm` in
+the image, and — because the prune's real risk is *removing something
+needed*, not size — esbuild must compile TS and clipboard must load its
+native binding at **every** install site.
+
+Two failure shapes to copy from those, both of which bit here:
+- `test ! -d /root/.npm` on mode-700 `/root` passes for a **permission**
+  error, so the cache assertion refuses to run as non-root. Watch for
+  this in any assertion about a path you may not be allowed to read.
+- `node -e 'require("esbuild")'` resolves by walking up from the CURRENT
+  DIRECTORY, so it fails with `MODULE_NOT_FOUND` from `/workspace` on a
+  perfectly healthy image (esbuild is nested inside the pi trees;
+  `NODE_PATH` is unset). Always path-qualify: `require("<abs>/esbuild")`.
+  A runbook shipped the bare form with "if this fails, revert the
+  release" attached, and it duly went red for the wrong reason.
 
 ## Build pipeline notes
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f3ed983..82f2629 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -78,6 +78,24 @@ RUN at the end of `Dockerfile.variant` calls `pi --version` again, so deleting
 it earlier only relocates those bytes into that layer — today's manifest layer
 is 128 kB precisely because it finds the cache warm.
 
+**Two functional assertions as well, after the runbook command left for the
+next machine failed for the wrong reason.** v1.9.1's open item prescribed
+`node -e 'require("esbuild").transformSync(...)'` as the post-boot check, with
+"if this fails, the prune removed something needed → revert to v1.8.14". Run
+from `/workspace` it fails with `MODULE_NOT_FOUND` on a perfectly good image:
+`require` resolves by walking up from the current directory, esbuild lives
+nested inside the two pi trees, and global installs are not on node's require
+path (`NODE_PATH` is unset). The check that verified the prune last time only
+passed because the shell happened to be inside the tree. Smoke now does it
+properly and CI owns it: for every install site found in the image (so the
+studio variant's third site is covered automatically), esbuild must compile TS
+and `@mariozechner/clipboard` must load with its native binding attached — the
+latter is the real proof for the clipboard prune, since napi-rs resolves the
+platform package at `require()` time. Both were verified as a four-way matrix:
+green on the real image *from `/workspace`*, and red against copies of the same
+packages with the host platform binary removed (`The package
+"@esbuild/linux-arm64" could not be found`).
+
 Touches `Dockerfile.variant` and `scripts/smoke-test.sh` only: `Dockerfile.base`
 is unchanged, so this needs no base rebuild and should **ride the next release**
 rather than burn a cycle of its own.
diff --git a/scripts/smoke-test.sh b/scripts/smoke-test.sh
index 3298322..4813c84 100755
--- a/scripts/smoke-test.sh
+++ b/scripts/smoke-test.sh
@@ -30,6 +30,7 @@
 #     client bundle present + registered via `pi install`
 #   - no foreign npm-11 platform packages (@esbuild, clipboard) beyond the host
 #   - no build-time npm cache (/root/.npm) shipped in the image
+#   - esbuild compiles + clipboard native loads at every install site
 #   - image size within threshold
 
 set -euo pipefail
@@ -909,6 +910,27 @@ run "no foreign platform packages (npm 11 sentinel)" \
 run "no build-time npm cache shipped (/root/.npm)" \
   'test "$(id -u)" = "0" || { echo "assertion needs root to read /root" >&2; exit 1; }; if [ -e /root/.npm ]; then echo "/root/.npm shipped: $(du -sm /root/.npm | cut -f1) MB" >&2; exit 1; fi; echo ok'
 
+# The prune's risk is not "too big" but "removed something needed", and only a
+# FUNCTIONAL check covers that. These load the natives from every install site
+# found in the image, so they also scale to the studio variant's third site.
+#
+# NOTE THE PATH-QUALIFIED require(). The obvious form, `node -e
+# 'require("esbuild")...'`, resolves by walking up from the CURRENT DIRECTORY —
+# so it fails with MODULE_NOT_FOUND from /workspace on a perfectly good image,
+# because esbuild lives nested inside the pi trees and global installs are not
+# on node's require path (NODE_PATH is unset). That exact command was left in a
+# runbook as "if this fails, revert the release", and it duly failed for the
+# wrong reason on the first machine that ran it. A check must fail only for the
+# thing it is checking.
+run "esbuild works at every install site (prune removed weight, not function)" \
+  'sites=$(find /usr/lib/node_modules /opt -type d -path "*/node_modules/esbuild" -prune 2>/dev/null); if [ -z "$sites" ]; then echo "no esbuild install found at all" >&2; exit 1; fi; for d in $sites; do node -e "require(\"$d\").transformSync(\"const x:number=1\",{loader:\"ts\"})" || { echo "esbuild broken at $d" >&2; exit 1; }; done; echo ok'
+
+# Clipboard is the family pruned second, and its napi-rs loader picks its native
+# binding at require() time — so a successful load IS the proof that the kept
+# platform package is the one this image needs.
+run "clipboard native loads at every install site" \
+  'sites=$(find /usr/lib/node_modules /opt -type d -path "*/node_modules/@mariozechner/clipboard" -prune 2>/dev/null); if [ -z "$sites" ]; then echo "no @mariozechner/clipboard install found at all" >&2; exit 1; fi; for d in $sites; do node -e "var c=require(\"$d\"); if (typeof c.setText !== \"function\") { throw new Error(\"native binding missing\"); }" || { echo "clipboard native broken at $d" >&2; exit 1; }; done; echo ok'
+
 # ── Image size ────────────────────────────────────────────────────────
 echo ""
 echo "── Image size ──"