diff --git a/test/e2e/live/hermes-gpu-startup-integrity.ts b/test/e2e/live/hermes-gpu-startup-integrity.ts
index 20e09fc6e3f..16dbf661dca 100644
--- a/test/e2e/live/hermes-gpu-startup-integrity.ts
+++ b/test/e2e/live/hermes-gpu-startup-integrity.ts
@@ -76,18 +76,23 @@ def parse_hash(data, label):
         text = data.decode("ascii")
     except UnicodeDecodeError:
         fail(f"{label} is not ASCII")
-    if not text.endswith("\\n"):
-        fail(f"{label} is missing its final newline")
-    lines = text.splitlines()
+    parts = text.split("\\n")
+    if len(parts) != 4 or parts[-1] != "":
+        fail(f"{label} does not contain exactly three records")
+    lines = parts[:2]
     expected_paths = (str(config_path), str(env_path))
-    if len(lines) != len(expected_paths):
-        fail(f"{label} does not contain exactly two records")
     digests = []
     for line, expected_path in zip(lines, expected_paths):
         match = re.fullmatch(r"([0-9a-f]{64})  (.+)", line)
         if match is None or match.group(2) != expected_path:
-            fail(f"{label} contains an unexpected record")
+            fail(f"{label} contains an unexpected file record")
         digests.append(match.group(1))
+    state_match = re.fullmatch(
+        r"# nemoclaw-hermes-mcp-state-v1 intended=([0-9a-f]{64}) applied=([0-9a-f]{64})",
+        parts[2],
+    )
+    if state_match is None:
+        fail(f"{label} contains an unexpected MCP state record")
     return tuple(digests)
 
 def digest(data):
diff --git a/test/e2e/support/hermes-gpu-startup-integrity.test.ts b/test/e2e/support/hermes-gpu-startup-integrity.test.ts
index 37ecf2db9de..8a473179ba9 100644
--- a/test/e2e/support/hermes-gpu-startup-integrity.test.ts
+++ b/test/e2e/support/hermes-gpu-startup-integrity.test.ts
@@ -22,6 +22,7 @@ interface IntegrityFixture {
 }
 
 const roots: string[] = [];
+const MCP_STATE_RECORD = `# nemoclaw-hermes-mcp-state-v1 intended=${"1".repeat(64)} applied=${"2".repeat(64)}`;
 
 afterEach(() => {
   for (const root of roots.splice(0)) fs.rmSync(root, { recursive: true, force: true });
@@ -38,7 +39,18 @@ function writeHash(
   envPath: string,
   env: string,
 ): void {
-  fs.writeFileSync(hashPath, `${digest(config)}  ${configPath}\n${digest(env)}  ${envPath}\n`);
+  fs.writeFileSync(
+    hashPath,
+    `${digest(config)}  ${configPath}\n${digest(env)}  ${envPath}\n${MCP_STATE_RECORD}\n`,
+  );
+}
+
+function readHashRecords(hashPath: string): string[] {
+  return fs.readFileSync(hashPath, "utf-8").split("\n").slice(0, -1);
+}
+
+function writeHashRecords(hashPath: string, records: readonly string[]): void {
+  fs.writeFileSync(hashPath, `${records.join("\n")}\n`);
 }
 
 function createFixture(): IntegrityFixture {
@@ -96,7 +108,7 @@ function runProof(fixture: IntegrityFixture, extraEnv: NodeJS.ProcessEnv = {}) {
 }
 
 describe("Hermes managed startup integrity proof", () => {
-  it("accepts a current compatibility hash and one generated API key beyond the strict base", () => {
+  it("accepts canonical file and MCP state records with one generated API key beyond the strict base (#6427)", () => {
     const fixture = createFixture();
     const rawStrictCheck = spawnSync("sha256sum", ["-c", fixture.strictHashPath, "--status"], {
       encoding: "utf-8",
@@ -111,6 +123,68 @@ describe("Hermes managed startup integrity proof", () => {
     expect(proof.stdout).toBe("OK\n");
   });
 
+  it("rejects a missing Hermes MCP state record (#6427)", () => {
+    const fixture = createFixture();
+    const [configRecord, envRecord] = readHashRecords(fixture.compatHashPath);
+    writeHashRecords(fixture.compatHashPath, [configRecord!, envRecord!]);
+
+    const proof = runProof(fixture);
+    expect(proof.status).not.toBe(0);
+    expect(proof.stderr).toContain(
+      "Hermes compatibility hash does not contain exactly three records",
+    );
+  });
+
+  it("rejects a malformed Hermes MCP state record (#6427)", () => {
+    const fixture = createFixture();
+    const [configRecord, envRecord] = readHashRecords(fixture.compatHashPath);
+    writeHashRecords(fixture.compatHashPath, [
+      configRecord!,
+      envRecord!,
+      `# nemoclaw-hermes-mcp-state-v1 intended=${"1".repeat(64)} applied=invalid`,
+    ]);
+
+    const proof = runProof(fixture);
+    expect(proof.status).not.toBe(0);
+    expect(proof.stderr).toContain(
+      "Hermes compatibility hash contains an unexpected MCP state record",
+    );
+  });
+
+  it("rejects duplicate Hermes MCP state records (#6427)", () => {
+    const fixture = createFixture();
+    const records = readHashRecords(fixture.compatHashPath);
+    writeHashRecords(fixture.compatHashPath, [...records, MCP_STATE_RECORD]);
+
+    const proof = runProof(fixture);
+    expect(proof.status).not.toBe(0);
+    expect(proof.stderr).toContain(
+      "Hermes compatibility hash does not contain exactly three records",
+    );
+  });
+
+  it("rejects a reordered Hermes MCP state record (#6427)", () => {
+    const fixture = createFixture();
+    const [configRecord, envRecord, stateRecord] = readHashRecords(fixture.compatHashPath);
+    writeHashRecords(fixture.compatHashPath, [stateRecord!, configRecord!, envRecord!]);
+
+    const proof = runProof(fixture);
+    expect(proof.status).not.toBe(0);
+    expect(proof.stderr).toContain("Hermes compatibility hash contains an unexpected file record");
+  });
+
+  it("rejects unexpected records after the Hermes MCP state record (#6427)", () => {
+    const fixture = createFixture();
+    const records = readHashRecords(fixture.compatHashPath);
+    writeHashRecords(fixture.compatHashPath, [...records, "unexpected"]);
+
+    const proof = runProof(fixture);
+    expect(proof.status).not.toBe(0);
+    expect(proof.stderr).toContain(
+      "Hermes compatibility hash does not contain exactly three records",
+    );
+  });
+
   it("rejects non-key environment drift even when the compatibility hash accepts it", () => {
     const fixture = createFixture();
     const config = fs.readFileSync(fixture.configPath, "utf-8");