diff --git a/tests/acceptance/1/CRITERIA.json b/tests/acceptance/1/CRITERIA.json
new file mode 100644
index 0000000..7c03e1c
--- /dev/null
+++ b/tests/acceptance/1/CRITERIA.json
@@ -0,0 +1,24 @@
+{
+  "schema": "elffuss-t2t/criteria@2",
+  "issue": 1,
+  "criteria": [
+    {
+      "index": 1,
+      "tests": [
+        "tests/acceptance/1/criteria.test.js::criterion 1"
+      ]
+    },
+    {
+      "index": 2,
+      "tests": [
+        "tests/acceptance/1/criteria.test.js::criterion 2"
+      ]
+    },
+    {
+      "index": 3,
+      "tests": [
+        "tests/acceptance/1/criteria.test.js::criterion 3"
+      ]
+    }
+  ]
+}
diff --git a/tests/acceptance/1/criteria.test.js b/tests/acceptance/1/criteria.test.js
new file mode 100644
index 0000000..dbe10de
--- /dev/null
+++ b/tests/acceptance/1/criteria.test.js
@@ -0,0 +1,26 @@
+import { test } from 'node:test'
+import assert from 'node:assert/strict'
+import { readFileSync } from 'node:fs'
+import * as mod from '../../../web/js/runtime/caps.js' // the code under test: call it as mod.<name>(...)
+const source = readFileSync(new URL('../../../web/js/runtime/caps.js', import.meta.url), 'utf8') // the text of web/js/runtime/caps.js, for a criterion about how the file is written
+
+test('criterion 1', () => {
+  // `summarize` of a capability object whose `memGB` field is missing returns a string that does not contain `undefined`.
+  const cap = { name: 'test' }
+  const summary = mod.summarize(cap)
+  assert.assert.notInclude(summary, 'undefined')
+})
+
+test('criterion 2', () => {
+  // `summarize` of a capability object whose `memGB` field is missing returns a string that contains `~?GB RAM`.
+  const cap = { name: 'test' }
+  const summary = mod.summarize(cap)
+  assert.assert.include(summary, '~?GB RAM')
+})
+
+test('criterion 3', () => {
+  // `summarize` of a capability object whose `memGB` is a number returns a string that contains that number immediately followed by `GB RAM`.
+  const cap = { name: 'test', memGB: 4 }
+  const summary = mod.summarize(cap)
+  assert.assert.include(summary, '4GB RAM')
+})
diff --git a/web/js/runtime/caps.js b/web/js/runtime/caps.js
index db6a3a7..bc53ce2 100644
--- a/web/js/runtime/caps.js
+++ b/web/js/runtime/caps.js
@@ -105,8 +105,6 @@ export async function probe() {
 export function summarize(c) {
   const p = c.platform.iOS ? 'iOS' : c.platform.android ? 'Android'
     : c.platform.mac ? 'Mac' : c.platform.mobile ? 'móvil' : 'escritorio';
-  const g = c.gpu
-    ? `WebGPU · buffer≤${(c.limits.maxBufferSize / GiB).toFixed(1)}GiB · binding≤${(c.limits.maxStorageBufferBindingSize / MiB) | 0}MiB`
-    : `sin GPU (${c.error || '—'})`;
-  return `${p} · ~${c.memGB}GB RAM · presupuesto ${c.budgetGiB}GiB · ${g}`;
+  const g = c.gpu ? `WebGPU · buffer≤${(c.limits.maxBufferSize / GiB).toFixed(1)}GiB · binding≤${(c.limits.maxStorageBufferBindingSize / MiB) | 0}MiB` : `sin GPU (${c.error || '—'})`;
+  return `${p} · ~${c.memGB !== undefined ? c.memGB : '?'}GB RAM · presupuesto ${c.budgetGiB}GiB · ${g}`;
 }