diff --git a/e2e/e3-bench.mjs b/e2e/e3-bench.mjs
new file mode 100644
index 0000000..2d13a64
--- /dev/null
+++ b/e2e/e3-bench.mjs
@@ -0,0 +1,23 @@
+// E3: browser-tier benchmark through the LIVE /neural page (paper C).
+import { chromium } from "@playwright/test"
+
+const URL = "https://interscript.org/neural"
+const MODEL = "tha-g2p-small-1.0" // smallest tier for a headless-runnable pass
+const browser = await chromium.launch()
+const page = await browser.newPage()
+
+const t0 = Date.now()
+await page.goto(URL, { waitUntil: "networkidle" })
+console.log(`page load: ${Date.now() - t0} ms`)
+
+await page.selectOption("#model", MODEL)
+await page.evaluate(() => caches.keys().then((k) => Promise.all(k.map((n) => caches.delete(n)))))
+for (const pass of ["cold", "warm"]) {
+  const t1 = Date.now()
+  await page.click("#run")
+  await page.waitForFunction(() => document.getElementById("output").textContent.length > 0, null, { timeout: 600000 })
+  const out = await page.textContent("#output")
+  console.log(`${pass} resolve+session+decode: ${Date.now() - t1} ms (out ${out.length}B)`)
+  if (pass === "cold") await page.click("#clear-cache")
+}
+await browser.close()
diff --git a/e2e/e3-debug.mjs b/e2e/e3-debug.mjs
new file mode 100644
index 0000000..dd46660
--- /dev/null
+++ b/e2e/e3-debug.mjs
@@ -0,0 +1,16 @@
+import { chromium } from "@playwright/test"
+const b = await chromium.launch()
+const p = await b.newPage()
+await p.goto("https://interscript.org/neural", { waitUntil: "networkidle" })
+const res = await p.evaluate(async () => {
+  try {
+    const r = await fetch("https://github.com/interscript/interscript-ml/releases/download/index-v2/models-index.yaml.sha256")
+    return `ok ${r.status}`
+  } catch (e) { return `FAIL ${e.message} | ${e.cause?.message ?? ""}` }
+})
+console.log("index fetch:", res)
+const same = await p.evaluate(async () => {
+  try { const r = await fetch("/v1/info"); return `ok ${r.status}` } catch (e) { return `FAIL ${e.message}` }
+})
+console.log("same-origin:", same)
+await b.close()
diff --git a/package-lock.json b/package-lock.json
index 8c838cb..c3685bc 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -20,7 +20,7 @@
         "@iso24229/iso639-data": "^0.2.0",
         "@tailwindcss/vite": "^4.0.0",
         "astro": "^7.0.0",
-        "interscript": "^5.2.0",
+        "interscript": "^5.2.1",
         "onnxruntime-web": "^1.29.0",
         "tailwindcss": "^4.0.0",
         "vue": "^3.5.0"
@@ -6427,9 +6427,9 @@
       "license": "ISC"
     },
     "node_modules/interscript": {
-      "version": "5.2.0",
-      "resolved": "https://registry.npmjs.org/interscript/-/interscript-5.2.0.tgz",
-      "integrity": "sha512-PFbDiYX/rMareAjKluBqv3vRBOBTC37Enc9hLAyb/pfrWSatHGQeFizj1wv0KoDocW8vRFLpSxY3PKi86Io77g==",
+      "version": "5.2.1",
+      "resolved": "https://registry.npmjs.org/interscript/-/interscript-5.2.1.tgz",
+      "integrity": "sha512-iZJa5ErX4gMpFB1j4MLyrWccLJa6MTLAosXW3Pi2t1BcMGrl8Q+E8dV3I+R6NNoGgFsc2B0GK4BEuKP3ARZvoA==",
       "license": "BSD-2-Clause",
       "dependencies": {
         "fflate": "^0.8.3",
diff --git a/package.json b/package.json
index 2c68853..1ee7185 100644
--- a/package.json
+++ b/package.json
@@ -33,7 +33,7 @@
     "@iso24229/iso639-data": "^0.2.0",
     "@tailwindcss/vite": "^4.0.0",
     "astro": "^7.0.0",
-    "interscript": "^5.2.0",
+    "interscript": "^5.2.1",
     "onnxruntime-web": "^1.29.0",
     "tailwindcss": "^4.0.0",
     "vue": "^3.5.0"
diff --git a/src/pages/neural.astro b/src/pages/neural.astro
index 9a6c84c..376ad55 100644
--- a/src/pages/neural.astro
+++ b/src/pages/neural.astro
@@ -137,7 +137,8 @@ import Base from "../layouts/Base.astro"
         conf.textContent = `Decode confidence: min top-2 gap ${min.toFixed(2)} across ${gaps.length} steps (lower = less certain)`
       }
     } catch (e) {
-      out.textContent = `Error: ${(e as Error).message}`
+      const cause = (e as Error).cause as Error | undefined
+      out.textContent = `Error: ${(e as Error).message}${cause ? " | cause: " + cause.message : ""}`
     }
   })