@@ -293,6 +293,92 @@ async function debugZoneWithdrawal(parameters: {
       } as never),
     )
 
+  // Shared Zone runtime code installed on L1.
+  for (const [name, address] of [
+    ['factory', '0x5aF2000000000000000000000000000000000000'],
+    ['messenger', '0x5A4D000000000000000000000000000000000000'],
+    ['portalImpl', '0x5AD1000000000000000000000000000000000000'],
+    ['verifier', '0x5A56000000000000000000000000000000000000'],
+    ['portalProxy', portalAddress],
+    ['signatureVerifier', Addresses.signatureVerifier],
+  ] as const)
+    await safe(`code.${name}`, async () => {
+      const code = (await mainnetClient.request({
+        method: 'eth_getCode',
+        params: [address, 'latest'],
+      })) as Hex
+      return `${(code.length - 2) / 2} bytes, keccak ${keccak256(code)}, head ${code.slice(0, 26)}`
+    })
+
+  // Direct call of the shared verifier with the arguments the portal would pass.
+  const verifierAbi = [
+    {
+      name: 'verify',
+      type: 'function',
+      stateMutability: 'pure',
+      inputs: [
+        { type: 'uint32' },
+        { type: 'uint64' },
+        { type: 'uint64' },
+        { type: 'bytes32' },
+        { type: 'uint64' },
+        {
+          type: 'tuple',
+          components: [{ type: 'bytes32' }, { type: 'bytes32' }],
+        },
+        {
+          type: 'tuple',
+          components: [
+            { type: 'bytes32' },
+            { type: 'bytes32' },
+            { type: 'uint64' },
+            { type: 'uint64' },
+          ],
+        },
+        { type: 'bytes32' },
+        { type: 'bytes' },
+        { type: 'bytes' },
+      ],
+      outputs: [{ type: 'bool' }],
+    },
+  ] as const
+  await safe('verifier.verify(direct)', async () => {
+    try {
+      return await mainnetClient.request({
+        method: 'eth_call',
+        params: [
+          {
+            from: portalAddress,
+            to: '0x5A56000000000000000000000000000000000000',
+            data: encodeFunctionData({
+              abi: verifierAbi,
+              functionName: 'verify',
+              args: [
+                1,
+                BigInt(latest) - 5n,
+                BigInt(latest) - 5n,
+                keccak256('0x03'),
+                1n,
+                { 0: zeroHash, 1: keccak256('0x01') } as never,
+                { 0: zeroHash, 1: zeroHash, 2: 0n, 3: 0n } as never,
+                keccak256('0x02'),
+                '0x',
+                '0x',
+              ],
+            }),
+          },
+          'latest',
+        ],
+      } as never)
+    } catch (error) {
+      const e = error as Error & { cause?: unknown }
+      return {
+        error: e.message.split('\n')[0],
+        cause: JSON.stringify(e.cause)?.slice(0, 300),
+      }
+    }
+  })
+
   // Signature verifier precompile with a Zone-style 65-byte (v = 27/28) signature.
   const probeHash = keccak256('0xdead')
   const probeSignature = await account.sign({ hash: probeHash })