diff --git a/packages/compiler/src/executable/prepare.ts b/packages/compiler/src/executable/prepare.ts
index 90504d0ef..5f3e45c9a 100644
--- a/packages/compiler/src/executable/prepare.ts
+++ b/packages/compiler/src/executable/prepare.ts
@@ -461,10 +461,13 @@ function preflightIslands(
 
 /** Packages compiled natively with runtime fences (refusals deferred to the
  * operation that reaches them) that should run in islands instead: those
- * whose island class is runtime (R1) or object-model (R2), by NI-2's report
- * over the pre-scan markers and the fences, or with a fence that itself
- * needs the runtime. Gap-only packages keep their fences until decision 8
- * (D6) retires them. `--node-islands=auto` only; null for none. */
+ * with a fence that surely fires (one in top-level module code, which runs
+ * when the module evaluates) or that itself needs the runtime (R1). Other
+ * fences stay deferred refusals until decision 8 (D6) retires them, so
+ * typed packages like jose stay native. With `requireFence` false (after a
+ * failed build) the package's island class by NI-2's report decides
+ * instead: runtime (R1) or object-model (R2). `--node-islands=auto` only;
+ * null for none. */
 function fenceIslands(
   entryPath: string,
   opts: CompileRequestOptions,
@@ -515,6 +518,11 @@ function fenceIslands(
     if (runtimeFence === undefined || island.path === null) continue;
     if (!compiled.has(island.package) || known.has(island.package)) continue;
     if (policy.forcedNative.has(island.package) || policy.unloaded.has(island.package)) continue;
+    // With fences (requireFence), only fences that surely fire count: a
+    // gap fence inside a function body may never run (jose's typed paths
+    // stay native, DECISIONS.md 2026-10-21). After a failed build
+    // (!requireFence), the package's report class decides.
+    if (requireFence && !runtimeFence) continue;
     if (!runtimeFence && island.class !== "runtime" && island.class !== "object-model") continue;
     grown.set(island.package, {
       name: island.package,
diff --git a/packages/libnode-common/bridge/scr_node_bridge.cc b/packages/libnode-common/bridge/scr_node_bridge.cc
index d63a3b6f1..45430e4a7 100644
--- a/packages/libnode-common/bridge/scr_node_bridge.cc
+++ b/packages/libnode-common/bridge/scr_node_bridge.cc
@@ -1444,6 +1444,11 @@ Local<Value> ExportValue(Isolate *isolate, Local<Context> context, const ScrNode
   } else {
     obj = ExportTemplate(isolate)->NewInstance(context).ToLocalChecked();
     obj->SetInternalField(0, data);
+    // A template instance inherits from its implicit constructor's own
+    // prototype object; a native plain object is a plain object to island
+    // code (`Object.getPrototypeOf(o) === Object.prototype`, as jose's
+    // isObject checks), so it inherits Object.prototype directly.
+    obj->SetPrototypeV2(context, v8::Object::New(isolate)->GetPrototypeV2()).FromMaybe(false);
   }
   if (!obj->IsProxy()) obj->SetPrivate(context, ExportKey(isolate), data).Check();
   Global<Object> &slot = g_exports[id];
diff --git a/tests/corpus/6331-jose-root-entry/package.json b/tests/corpus/6331-jose-root-entry/package.json
deleted file mode 100644
index 30d3e0af0..000000000
--- a/tests/corpus/6331-jose-root-entry/package.json
+++ /dev/null
@@ -1 +0,0 @@
-{ "type": "module", "scriptc": { "packages": { "jose": "native" } } }
diff --git a/tests/corpus/6610-npm-execa-child-mixin/package.json b/tests/corpus/6610-npm-execa-child-mixin/package.json
deleted file mode 100644
index 5a418a30c..000000000
--- a/tests/corpus/6610-npm-execa-child-mixin/package.json
+++ /dev/null
@@ -1 +0,0 @@
-{ "type": "module", "scriptc": { "packages": { "run-node": "native" } } }
diff --git a/tests/corpus/6826-node-island-undefined-args/main.ts b/tests/corpus/6826-node-island-undefined-args/main.ts
index 94a350e67..5f6fb53e9 100644
--- a/tests/corpus/6826-node-island-undefined-args/main.ts
+++ b/tests/corpus/6826-node-island-undefined-args/main.ts
@@ -12,6 +12,7 @@ import {
   nodeVersionFor,
   cwd,
   envValue,
+  plain,
   type Config,
 } from "argprobe";
 import { mkdtempSync, writeFileSync, rmSync } from "node:fs";
@@ -54,6 +55,8 @@ const none = projectSettings(false);
 console.log(version("/work", "unused", { nodeVersion: project?.nodeVersion }, undefined, available));
 console.log(version("/work", "unused", { nodeVersion: none?.nodeVersion }, undefined, available));
 console.log(probe("p", { nodeVersion: project?.nodeVersion }), probe("n", { nodeVersion: none?.nodeVersion }));
+const claims = { role: "admin" };
+console.log("plain", plain({ sub: "alice" }), plain(claims));
 
 async function main(): Promise<void> {
   // A package.json the program writes just before the island reads it.
diff --git a/tests/corpus/6826-node-island-undefined-args/node_modules/argprobe/index.d.ts b/tests/corpus/6826-node-island-undefined-args/node_modules/argprobe/index.d.ts
index 72cde09b4..6ce43de4d 100644
--- a/tests/corpus/6826-node-island-undefined-args/node_modules/argprobe/index.d.ts
+++ b/tests/corpus/6826-node-island-undefined-args/node_modules/argprobe/index.d.ts
@@ -21,3 +21,4 @@ export declare function nodeVersionFor(
 ): Promise<string>;
 export declare function cwd(): string;
 export declare function envValue(name: string): string | undefined;
+export declare function plain(v: object): string;
diff --git a/tests/corpus/6826-node-island-undefined-args/node_modules/argprobe/index.js b/tests/corpus/6826-node-island-undefined-args/node_modules/argprobe/index.js
index 5a9e4245e..5cf8f9301 100644
--- a/tests/corpus/6826-node-island-undefined-args/node_modules/argprobe/index.js
+++ b/tests/corpus/6826-node-island-undefined-args/node_modules/argprobe/index.js
@@ -68,3 +68,11 @@ exports.nodeVersionFor = async function nodeVersionFor(
 
 exports.cwd = () => process.cwd();
 exports.envValue = (name) => process.env[name];
+
+// A native plain object is a plain object here (jose's isObject).
+exports.plain = (v) =>
+  [
+    Object.getPrototypeOf(v) === Object.prototype,
+    Object.prototype.toString.call(v),
+    Object.getPrototypeOf(Object.getPrototypeOf(v)) === null,
+  ].join(" ");
diff --git a/tests/harness/npm.test.ts b/tests/harness/npm.test.ts
index d08a4c0fb..3643a9859 100644
--- a/tests/harness/npm.test.ts
+++ b/tests/harness/npm.test.ts
@@ -66,46 +66,42 @@ const KNOWN: Record<string, Known> = {
     divergence:
       "Timeout handles are numbers (typeof) and lose their ref flag once fired or cleared",
   },
-  "hot-shots-udp": {
-    divergence:
-      "as a Node island (its runtime fences pick one), output stops after the socket-not-running error; the built-in hot-shots shim (#1836) compiles it natively",
-  },
   "island-web-plumbing": { run: "SC2020" },
   "lazy-traps": { island: true },
-  "misc-shims": { island: true },
+  "misc-shims": { run: "SC2020" },
   namespace: { island: true },
   "node24-async-events": { run: "SC2020" },
   "node24-commonjs-metadata": { island: true },
   "node24-crypto-kdf": { run: "SC2020" },
-  "node24-deep-equality": { island: true },
+  "node24-deep-equality": { run: "SC2020" },
   "node24-diagnostics-async": { run: "SC1090" },
   "node24-diagnostics-tracing": { run: "SC1090" },
-  "node24-env": { island: true },
+  "node24-env": { run: "SC1090" },
   "node24-esm-metadata": { island: true },
   "node24-event-emitter": { run: "SC2020" },
   "node24-file-url-conversion": { island: true },
   "node24-fs-descriptors": { run: "SC2020" },
-  "node24-mime": { island: true },
-  "node24-mime-errors": { island: true },
+  "node24-mime": { run: "SC2020" },
+  "node24-mime-errors": { run: "SC1090" },
   "node24-no-error-assertions": { run: "SC2020" },
-  "node24-parseargs": { island: true },
+  "node24-parseargs": { run: "SC1090" },
   "node24-promise-timers": { run: "SC2020" },
   "node24-string-decoder": { run: "SC2020" },
-  "node24-style-text": { island: true },
+  "node24-style-text": { run: "SC2020" },
   "node24-system-errors": { run: "SC1090" },
   "node24-text-encoding": { run: "SC2020" },
   "node24-text-utilities": { run: "SC2020" },
   "node24-timers-unref": { run: "SC2020" },
   "node24-url-factories": { run: "SC2020" },
   "node24-url-mutation": { run: "SC1090" },
-  "node24-util-adapters": { island: true },
-  "node24-util-types": { island: true },
+  "node24-util-adapters": { run: "Object.create with this value is not supported yet" },
+  "node24-util-types": { run: "SC1090" },
   "node24-web-stream-encoding": { run: "SC1090" },
   "node24-web-stream-errors": { run: "SC1090" },
   "node24-web-stream-lifecycle": { run: "SC1090" },
   "node24-web-stream-pipe-abort": { run: "SC2020" },
   "node24-web-stream-pipe-errors": { run: "SC1090" },
-  "node24-web-stream-pipes": { island: true },
+  "node24-web-stream-pipes": { run: "SC1090" },
   "node24-web-stream-queues": { run: "SC1090" },
   "node24-web-stream-readable-lifecycle": { run: "SC2020" },
   "node24-web-stream-readers": { run: "SC1090" },
@@ -114,8 +110,8 @@ const KNOWN: Record<string, Known> = {
   "package-imports": { island: true },
   "promise-bridge": { build: "SC1090" },
   "self-name": { build: "SC2013" },
-  "stream-shims": { island: true },
-  "util-shims": { island: true },
+  "stream-shims": { run: "SC1090" },
+  "util-shims": { run: "SC2020" },
   "web-streams": { run: "SC1090" },
   "workspace-copied": { island: true },
   "workspace-unclean": { build: "SC2013" },