diff --git a/src/resources/extensions/sf/auto-supervisor.ts b/src/resources/extensions/sf/auto-supervisor.ts
index 1880285d3..e393c15ed 100644
--- a/src/resources/extensions/sf/auto-supervisor.ts
+++ b/src/resources/extensions/sf/auto-supervisor.ts
@@ -7,6 +7,7 @@
 import { clearLock } from "./crash-recovery.js";
 import { nativeHasChanges } from "./native-git-bridge.js";
 import { releaseSessionLock } from "./session-lock.js";
+import { logWarning } from "./workflow-logger.js";
 
 // ─── Signal Handling ─────────────────────────────────────────────────────────
 
@@ -50,8 +51,13 @@ export function registerSigtermHandler(
 	const handler = () => {
 		try {
 			onSignal?.();
-		} catch {
-			// Best-effort: signal handler must not throw.
+		} catch (err) {
+			// Best-effort: signal handler must not throw — log and continue
+			// to lock cleanup so the user can still exit cleanly.
+			logWarning(
+				"session",
+				`auto-supervisor signal handler threw: ${(err as Error).message}`,
+			);
 		}
 		clearLock(currentBasePath);
 		releaseSessionLock(currentBasePath);
diff --git a/src/resources/extensions/sf/tests/auto-session-encapsulation.test.ts b/src/resources/extensions/sf/tests/auto-session-encapsulation.test.ts
index 510c5b41f..b69ee91b7 100644
--- a/src/resources/extensions/sf/tests/auto-session-encapsulation.test.ts
+++ b/src/resources/extensions/sf/tests/auto-session-encapsulation.test.ts
@@ -79,14 +79,19 @@ test("auto.ts has exactly one module-level const for AutoSession", () => {
 	const source = getAutoTsSource();
 	const lines = source.split("\n");
 
+	// Accept either historical shape: a direct `new AutoSession()` instantiation
+	// OR the current factory pattern `getAutoSession()` (auto/session.ts owns
+	// the singleton). The invariant is "exactly one module-level binding for
+	// the AutoSession instance" — not which constructor expression yielded it.
 	const sessionConsts = lines.filter((line) =>
-		/^const\s+\w+\s*=\s*new\s+AutoSession/.test(line),
+		/^const\s+\w+\s*=\s*(new\s+AutoSession|getAutoSession\s*\()/.test(line),
 	);
 
 	assert.equal(
 		sessionConsts.length,
 		1,
-		`auto.ts should have exactly one \`const s = new AutoSession()\`. ` +
+		`auto.ts should have exactly one module-level AutoSession binding ` +
+			`(\`const s = new AutoSession()\` or \`const s = getAutoSession()\`). ` +
 			`Found ${sessionConsts.length}: ${sessionConsts.join(", ")}`,
 	);
 });
@@ -212,7 +217,8 @@ test("auto.ts module-level consts are only AutoSession instance, true constants,
 
 	// Patterns that are acceptable at module level
 	const allowedPatterns = [
-		/^const s = new AutoSession/, // The session singleton
+		/^const s = new AutoSession/, // The session singleton (legacy shape)
+		/^const s = getAutoSession\s*\(/, // The session singleton (factory shape)
 		/^const [A-Z_]+\s*=/, // UPPER_CASE constants
 		/^const \w+StateAccessors/, // Static accessor objects
 		/^const \w+:\s*\w+\s*=/, // Typed constants