diff --git a/changelog.d/fixes/stryker-tapfiles-drift-release-line.md b/changelog.d/fixes/stryker-tapfiles-drift-release-line.md
new file mode 100644
index 0000000000..bf3e37a56b
--- /dev/null
+++ b/changelog.d/fixes/stryker-tapfiles-drift-release-line.md
@@ -0,0 +1,2 @@
+- **fix(ci):** register the four unit tests whose mutant kills were not counting — `daily-reset-tz-threading`, `noauth-model-lockout`, `free-badge-provider-gate` and `local-token-budget-429-skips-cooldown` — in `stryker.conf.json` `tap.testFiles`. `check-mutation-test-coverage --strict` reported 6 missing coverings across 4 mutated modules (`accountFallback`, `sse/services/auth`, `combo/comboPredicates`, `combo/rrState`) on the release line itself with no PR diff involved, so the `mutation-test-coverage` gate was red on every open PR regardless of its contents; the gate now reports no drift
+- fix(ci): drop a `tap.testFiles` entry naming a deleted test file, and guard the direction the existing drift check never covered — an entry left behind after its test is removed or renamed costs mutation coverage silently, because Stryker resolves the list into its sandbox without failing on a dangling path ([#13814](https://github.com/diegosouzapw/OmniRoute/pull/13814))
diff --git a/stryker.conf.json b/stryker.conf.json
index a821949e9f..d2e063b572 100644
--- a/stryker.conf.json
+++ b/stryker.conf.json
@@ -62,6 +62,7 @@
       "tests/unit/combo-pin-implicit-allowlist.test.ts",
       "tests/unit/combo-predicates-epoch-cooldown.test.ts",
       "tests/unit/combo/execute-target-gates.test.ts",
+      "tests/unit/daily-reset-tz-threading.test.ts",
       "tests/unit/moonshot-quota-writeback.test.ts",
       "tests/unit/accountfallback-ratelimit-400-4976.test.ts",
       "tests/unit/adaptive-admission-route-matrix.test.ts",
@@ -331,6 +332,7 @@
       "tests/unit/antigravityUpstreamError.test.ts",
       "tests/unit/issue-13089-roundrobin-live-ws-events.test.ts",
       "tests/unit/ollama-404-model-lockout-11071.test.ts",
+      "tests/unit/noauth-model-lockout.test.ts",
       "tests/unit/non-streaming-client-translate.test.ts",
       "tests/unit/non-streaming-provider-leg.test.ts",
       "tests/unit/non-streaming-sse-terminal-typescan-4459.test.ts",
@@ -353,7 +355,6 @@
       "tests/unit/permanent-failure-hammering-other-providers.test.ts",
       "tests/unit/persist-429-cooldown-account-fallback.test.ts",
       "tests/unit/plan3-p0.test.ts",
-      "tests/unit/plugin-sandbox-permissions.test.ts",
       "tests/unit/plugins-route-error-sanitization.test.ts",
       "tests/unit/probe-gate-autodisable.test.ts",
       "tests/unit/probe-production-path.test.ts",
diff --git a/tests/unit/build/check-mutation-test-coverage.test.ts b/tests/unit/build/check-mutation-test-coverage.test.ts
index acaf7f5736..a392e22068 100644
--- a/tests/unit/build/check-mutation-test-coverage.test.ts
+++ b/tests/unit/build/check-mutation-test-coverage.test.ts
@@ -1,5 +1,7 @@
 import { test } from "node:test";
 import assert from "node:assert/strict";
+import fs from "node:fs";
+import path from "node:path";
 import {
   moduleFragment,
   testImportsModule,
@@ -25,7 +27,10 @@ test("testImportsModule matches static, dynamic and require imports of the modul
   );
   // dynamic await import, even split across lines
   assert.equal(
-    testImportsModule(`const { y } = await import(\n  "../../open-sse/handlers/chatCore/headers.ts"\n);`, frag),
+    testImportsModule(
+      `const { y } = await import(\n  "../../open-sse/handlers/chatCore/headers.ts"\n);`,
+      frag
+    ),
     true
   );
   // require()
@@ -35,7 +40,10 @@ test("testImportsModule matches static, dynamic and require imports of the modul
   );
   // unrelated module is not matched
   assert.equal(
-    testImportsModule(`import { a } from "@omniroute/open-sse/handlers/chatCore/idempotency";`, frag),
+    testImportsModule(
+      `import { a } from "@omniroute/open-sse/handlers/chatCore/idempotency";`,
+      frag
+    ),
     false
   );
   // the fragment appearing only in a comment (not an import string) is NOT a match
@@ -54,11 +62,20 @@ test("findCoverageDrift flags covering unit tests absent from tap.testFiles", ()
   const tapTestFiles = ["tests/unit/chatcore-headers.test.ts"];
   const unitTests = [
     // covers headers, already in tap -> not drift
-    { path: "tests/unit/chatcore-headers.test.ts", content: `await import("../../open-sse/handlers/chatCore/headers.ts");` },
+    {
+      path: "tests/unit/chatcore-headers.test.ts",
+      content: `await import("../../open-sse/handlers/chatCore/headers.ts");`,
+    },
     // covers headers, NOT in tap -> drift
-    { path: "tests/unit/no-memory-header.test.ts", content: `const { isNoMemoryRequested } = await import("../../open-sse/handlers/chatCore/headers.ts");` },
+    {
+      path: "tests/unit/no-memory-header.test.ts",
+      content: `const { isNoMemoryRequested } = await import("../../open-sse/handlers/chatCore/headers.ts");`,
+    },
     // covers idempotency, NOT in tap -> drift
-    { path: "tests/unit/idempo.test.ts", content: `import { x } from "@omniroute/open-sse/handlers/chatCore/idempotency";` },
+    {
+      path: "tests/unit/idempo.test.ts",
+      content: `import { x } from "@omniroute/open-sse/handlers/chatCore/idempotency";`,
+    },
     // covers nothing mutated -> ignored
     { path: "tests/unit/unrelated.test.ts", content: `import { z } from "@/lib/foo";` },
   ];
@@ -72,3 +89,21 @@ test("findCoverageDrift flags covering unit tests absent from tap.testFiles", ()
   // comment-only mutate entries are skipped
   assert.equal("_a_comment_entry" in drift, false);
 });
+
+test("every tap.testFiles entry names a file that still exists", () => {
+  // The existing drift check runs one way: a test that covers a mutated module
+  // but is missing from tap.testFiles. The other way is silent — an entry left
+  // behind after its test file is deleted or renamed. Stryker resolves the list
+  // into its sandbox, so a dangling path costs coverage without failing loudly.
+  const repoRoot = path.resolve(import.meta.dirname, "../../..");
+  const conf = JSON.parse(fs.readFileSync(path.join(repoRoot, "stryker.conf.json"), "utf8")) as {
+    tap?: { testFiles?: string[] };
+  };
+  const entries = conf.tap?.testFiles ?? [];
+  assert.ok(entries.length > 0, "stryker.conf.json declares no tap.testFiles");
+
+  const missing = entries
+    .filter((entry) => !entry.includes("*"))
+    .filter((entry) => !fs.existsSync(path.join(repoRoot, entry)));
+  assert.deepEqual(missing, [], `tap.testFiles names ${missing.length} file(s) that do not exist`);
+});