diff --git a/packages/vscode/AGENTS.md b/packages/vscode/AGENTS.md
index 140d12b..0df73ad 100644
--- a/packages/vscode/AGENTS.md
+++ b/packages/vscode/AGENTS.md
@@ -7,7 +7,7 @@ One extension replacing the standalone `rstack.rslint` and `rstack.rstest` exten
 - `stacks/lint` and `stacks/test` are deliberate near-verbatim copies of the upstream extensions, kept close to upstream so changes can be synced by diffing. Do NOT deduplicate or refactor across the two stacks — the duplication is the point; consolidation is a later, explicit phase.
 - The copies diverge from upstream in exactly nine ways (the "adaptations" below). When syncing upstream, preserve them. A tenth divergence is either a bug or must be added to this list.
 - **Tracked upstream state.** `stacks/lint` is synced to web-infra-dev/rslint `packages/vscode-extension` at **39536fd6** (#1617 — per-document core resolution, `CoreResolver` + `RuntimeManager`, `corePath`, PnP removed) and **892482e0** (#1630 — `configPath` on `rslint/configRefresh`). Targeted later ports are **84f9c9b5** (#1967 — languageclient-owned live LSP tracing) and **b7176723** (#1951 — remove legacy JSON config watching); the Unicode BOM E2E comes from **5fc197a5** (#1560), with its native-config fixture shape from **b7176723**. `CoreResolver.ts` / `RuntimeManager.ts` / `WorkspaceDocumentRouter.ts` / `Rslint.ts` are the files to diff when syncing further; record the new commits here when you do.
-- **Ahead of upstream — offer these back when syncing** (bug fixes, not adaptations): (1) `RuntimeManager.reconcile` resolves the document's core **before** sweeping pending uses (`planDocumentCore`), so a reconcile landing on the key a pending start is already producing adopts that start instead of tearing it down mid-`initialize` — the teardown made vscode-languageclient force-notify ("couldn't create connection to server") whenever the register-time pass, a detection change and `didOpen` landed inside one worker startup window (`tests/stacks/lint/runtimeManager.test.ts`). (2) `Rslint.close()` gives a still-Starting language client a bounded chance to settle before tearing down its transport, so a legitimate mid-start close (document closed during start, core key changed) stops cleanly instead of triggering the same force-notified toasts.
+- **Ahead of upstream — offer these back when syncing** (bug fixes, not adaptations): (1) `RuntimeManager.reconcile` resolves the document's core **before** sweeping pending uses (`planDocumentCore`), so a reconcile landing on the key a pending start is already producing adopts that start instead of tearing it down mid-`initialize` — the teardown made vscode-languageclient force-notify ("couldn't create connection to server") whenever the register-time pass, a detection change and `didOpen` landed inside one worker startup window (`tests/stacks/lint/runtimeManager.test.ts`). (2) `Rslint.close()` gives a still-Starting language client a bounded chance to settle before tearing down its transport, so a legitimate mid-start close (document closed during start, core key changed) stops cleanly instead of triggering the same force-notified toasts. (3) The registry-harness E2E gives its never-settling startup operation 500ms to begin and accepts only the in-flight timeout message, so a stalled runner cannot satisfy the assertion through the already-expired path (`e2e/lint/suite/registry-harness.test.ts`).
 
 ## The nine adaptations
 
diff --git a/packages/vscode/e2e/lint/suite/registry-harness.test.ts b/packages/vscode/e2e/lint/suite/registry-harness.test.ts
index edc3f05..e6536d9 100644
--- a/packages/vscode/e2e/lint/suite/registry-harness.test.ts
+++ b/packages/vscode/e2e/lint/suite/registry-harness.test.ts
@@ -1,5 +1,6 @@
-// Ported verbatim from web-infra-dev/rslint
-// `packages/vscode-extension/__tests__/suite/registry-harness.test.ts` (origin/main).
+// Ported from web-infra-dev/rslint
+// `packages/vscode-extension/__tests__/suite/registry-harness.test.ts` (origin/main),
+// with startup-deadline hardening documented inline.
 import * as assert from 'assert';
 import { randomUUID } from 'node:crypto';
 import * as vscode from 'vscode';
@@ -125,10 +126,12 @@ suite('VS Code test harness fail-closed guards', function () {
           attempts += 1;
           return new Promise<void>(() => {});
         },
-        Date.now() + 50,
+        // Deviation from upstream (50ms): leave enough headroom for a stalled
+        // CI runner to start the operation before its shared deadline.
+        Date.now() + 500,
         'the injected startup operation',
       ),
-      /Timed out waiting for the injected startup operation.*shared startup deadline/,
+      /Timed out waiting for the injected startup operation before the shared startup deadline/,
     );
     assert.strictEqual(
       attempts,