diff --git a/js/viewer/README.md b/js/viewer/README.md
index 422eb46..270ac30 100644
--- a/js/viewer/README.md
+++ b/js/viewer/README.md
@@ -39,9 +39,10 @@ deliberate trap showing as tracked expected-fail debt on both targets.
 
 - `harness.mjs` — the browser-safe runner core: tag-inventory parsing
   (custom sections), mark scheduling, the per-case loop with shard
-  striping. Shared by the page's workers and the Node selftest; the
-  future gating jco adapter (#5) must use this same module — the gate
-  and the page must not drift.
+  striping and the opt-in gating-adapter options (#50: per-case fresh
+  instances, per-case wall bound). Shared by the page's workers and
+  the Node selftest; the gating jco adapters (#5) must use this same
+  module — the gate and the page must not drift.
 - `context.js` — the host-implemented `test-context` provider.
 - `worker.mjs` — one shard of a live run (module workers cannot see
   import maps, which is why every transpile here maps imports to
diff --git a/js/viewer/harness.mjs b/js/viewer/harness.mjs
index 1de7cbe..699b84f 100644
--- a/js/viewer/harness.mjs
+++ b/js/viewer/harness.mjs
@@ -106,6 +106,23 @@ export function envelope(target, suite) {
  * suite-order index alongside the event so a sharded consumer can
  * restore suite order.
  *
+ * The gating-adapter options (#50), both opt-in:
+ *
+ * `freshCases` gives every case a fresh instance: census and striping
+ * still come from `cases`, but each execution re-enumerates from the
+ * factory and runs the matching case (a vanished case throws — drift,
+ * unsound, not a failing case). For instantiation-mode transpiles this
+ * is the wasmtime runner's instance-per-case granularity; module-mode
+ * transpiles are singletons and cannot use it.
+ *
+ * `caseTimeoutMs` is the per-case wall bound (the runner's
+ * `--case-timeout`): on expiry the case fails with
+ * `{"limit-exceeded":"case-timeout"}` provenance and the loop moves
+ * on. JSPI attempts cannot be cancelled — the abandoned attempt keeps
+ * running until its instance is dropped, so pair this with
+ * `freshCases` (a timed-out shared instance may be wedged
+ * mid-suspension, poisoning every later case).
+ *
  * @param {object} options
  * @param {Array} options.cases  `tests.all()` from the transpiled suite.
  * @param {new (onDiagnostic: (msg: string) => void) => object} options.Context
@@ -114,9 +131,21 @@ export function envelope(target, suite) {
  * @param {string} [options.only]  Substring filter (skips emit entirely).
  * @param {(event: object, index: number) => void} options.emit
  * @param {{ index: number, count: number }} [options.shard]
+ * @param {() => Promise<Array>} [options.freshCases]
+ * @param {number} [options.caseTimeoutMs]
  * @returns {Promise<{passed, failed, skipped, na, total}>}
  */
-export async function runCases({ cases, Context, tagsOf, missing, only, emit, shard }) {
+export async function runCases({
+  cases,
+  Context,
+  tagsOf,
+  missing,
+  only,
+  emit,
+  shard,
+  freshCases,
+  caseTimeoutMs,
+}) {
   const { index: shardIndex, count: shardCount } = shard ?? { index: 0, count: 1 };
   let passed = 0, failed = 0, skipped = 0, na = 0, total = 0;
   for (const [caseIndex, testCase] of cases.entries()) {
@@ -136,13 +165,44 @@ export async function runCases({ cases, Context, tagsOf, missing, only, emit, sh
       emit({ case: name, status: "not-applicable", detail: excluding ?? "" }, caseIndex);
       continue;
     }
+    let executed = testCase;
+    if (freshCases) {
+      const fresh = await freshCases();
+      executed = fresh.find((c) => String(c.name()) === name);
+      if (!executed) {
+        throw new Error(`case ${name} vanished on re-enumeration`);
+      }
+    }
     const diags = [];
     const ctx = new Context((msg) => diags.push(msg));
     let event;
     try {
-      await testCase.run(ctx);
-      passed++;
-      event = { case: name, status: "pass", provenance: "returned" };
+      const attempt = executed.run(ctx);
+      let timedOut = false;
+      if (caseTimeoutMs) {
+        let timer;
+        timedOut = await Promise.race([
+          attempt.then(() => false),
+          new Promise((resolve) => {
+            timer = setTimeout(() => resolve(true), caseTimeoutMs);
+          }),
+        ]).finally(() => clearTimeout(timer));
+      } else {
+        await attempt;
+      }
+      if (timedOut) {
+        failed++;
+        event = {
+          case: name,
+          status: "fail",
+          provenance: { "limit-exceeded": "case-timeout" },
+          detail: `case timeout exceeded (${caseTimeoutMs / 1000}s)`,
+          "diagnostics-complete": false,
+        };
+      } else {
+        passed++;
+        event = { case: name, status: "pass", provenance: "returned" };
+      }
     } catch (e) {
       const payload = e?.payload ?? e;
       if (payload?.tag === "failed") {
diff --git a/js/viewer/selftest.mjs b/js/viewer/selftest.mjs
index 7ee3b14..e92423d 100644
--- a/js/viewer/selftest.mjs
+++ b/js/viewer/selftest.mjs
@@ -111,6 +111,70 @@ if (JSON.stringify(merged) !== JSON.stringify(fixture.counts)) {
   fail(`sharded counts diverge: ${JSON.stringify(merged)} vs ${JSON.stringify(fixture.counts)}`);
 }
 
+// --- 3. Gating-adapter options (#50): freshCases + caseTimeoutMs ----
+// Synthetic cases (the loop only needs name()/run()): a hanging case
+// must produce the limit-exceeded row and not stall the loop, every
+// execution must re-enumerate through the factory, and a case
+// vanishing on re-enumeration must throw (drift), not fail.
+{
+  const mkCase = (name, run) => ({ name: () => name, run });
+  const template = [
+    mkCase("synthetic/pass", async () => {}),
+    mkCase("synthetic/hang", () => new Promise(() => {})),
+    mkCase("synthetic/fail", async () => {
+      throw { payload: { tag: "failed", val: "boom" } };
+    }),
+  ];
+  let enumerations = 0;
+  const events = [];
+  const counts = await runCases({
+    cases: template,
+    Context,
+    tagsOf: () => [],
+    missing: [],
+    emit: (event) => events.push(event),
+    caseTimeoutMs: 100,
+    freshCases: async () => {
+      enumerations++;
+      return template;
+    },
+  });
+  if (counts.passed !== 1 || counts.failed !== 2 || counts.total !== 3) {
+    fail(`synthetic counts: ${JSON.stringify(counts)}`);
+  }
+  if (enumerations !== 3) {
+    fail(`freshCases enumerated ${enumerations} times, want one per case`);
+  }
+  const hang = events.find((e) => e.case === "synthetic/hang");
+  if (
+    hang?.status !== "fail" ||
+    hang?.provenance?.["limit-exceeded"] !== "case-timeout" ||
+    hang?.["diagnostics-complete"] !== false
+  ) {
+    fail(`hang row: ${JSON.stringify(hang)}`);
+  }
+  const failed = events.find((e) => e.case === "synthetic/fail");
+  if (failed?.provenance !== "returned" || failed?.detail !== "boom") {
+    fail(`payload mapping under the race: ${JSON.stringify(failed)}`);
+  }
+  let vanished = false;
+  try {
+    await runCases({
+      cases: [mkCase("synthetic/pass", async () => {})],
+      Context,
+      tagsOf: () => [],
+      missing: [],
+      emit: () => {},
+      freshCases: async () => [],
+    });
+  } catch {
+    vanished = true;
+  }
+  if (!vanished) {
+    fail("vanished case on re-enumeration did not throw");
+  }
+}
+
 console.log(
   `viewer selftest ok: aggregate ${JSON.stringify(doc.summary)}; ` +
     `sample ${JSON.stringify(sample.counts)}; fixture ${JSON.stringify(fixture.counts)}`,
diff --git a/package.json b/package.json
index 7f152ed..27dc443 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@lann/component-test-js",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "private": false,
   "type": "module",
   "description": "The lann:component-test stack's JS runner core, consumable as a rev-pinned git dependency (npm git installs cannot select subdirectories, so this facade lives at the repo root). Source-only by design: the browser-safe harness (tag inventory, mark scheduling, the case loop), the test-context provider, and the shard worker. Built artifacts (the viewer-aggregate engine) are deliberately excluded - they wait for registry publishing. Stability policy until then: pinned rev or nothing.",