diff --git a/specs/spec.md b/specs/spec.md
index 0440fd35f..f57bd4260 100644
--- a/specs/spec.md
+++ b/specs/spec.md
@@ -1293,7 +1293,7 @@ The state transition function produces:
 | `block_transition` | `prev_block_hash` to `next_block_hash` covering all blocks in the batch |
 | `deposit_queue_transition` | Deposit queue progress from the previous `(processed_hash, deposit_number)` pair to the next `(processed_hash, deposit_number)` pair |
 | `withdrawal_queue_hash` | Hash chain of withdrawals finalized in this batch (`0` if none) |
-| `last_batch_commitment` | `withdrawal_batch_index` read from `ZoneOutbox.lastBatch` |
+| `withdrawal_batch_index` | Withdrawal batch index read from `ZoneOutbox.lastBatch` |
 
 ### Block Execution (Stateless prover execution function)
 
@@ -1333,7 +1333,7 @@ The stateless execution function must reject the witness on any failed check, mi
     Require `TempoState.tempoBlockNumber == public_inputs.tempo_block_number`. If `anchor_block_number == tempo_block_number`, require `TempoState.tempoBlockHash == anchor_block_hash`. Otherwise, verify the parent-hash chain from `tempo_block_number` to `anchor_block_number` using `tempo_ancestry_headers`, ending at `anchor_block_hash`.
 
 12. **Return the batch outputs.**
-    Set `block_transition.prev_block_hash = public_inputs.prev_block_hash` and `block_transition.next_block_hash = prev_block_hash` after the final block. Set `deposit_queue_transition.prev_processed_hash` and `deposit_queue_transition.prev_deposit_number` to the values captured before executing the batch, and set `deposit_queue_transition.next_processed_hash` and `deposit_queue_transition.next_deposit_number` to the final inbox processed hash and processed deposit number. Set `withdrawal_queue_hash` and `last_batch_commitment.withdrawal_batch_index` from the final `ZoneOutbox.lastBatch` state.
+    Set `block_transition.prev_block_hash = public_inputs.prev_block_hash` and `block_transition.next_block_hash = prev_block_hash` after the final block. Set `deposit_queue_transition.prev_processed_hash` and `deposit_queue_transition.prev_deposit_number` to the values captured before executing the batch, and set `deposit_queue_transition.next_processed_hash` and `deposit_queue_transition.next_deposit_number` to the final inbox processed hash and processed deposit number. Set `withdrawal_queue_hash` and `withdrawal_batch_index` from the final `ZoneOutbox.lastBatch` state.
 
 ### Tempo State Proofs
 
@@ -1573,6 +1573,13 @@ struct DepositQueueTransition {
     uint64 nextDepositNumber;
 }
 
+struct BatchOutput {
+    BlockTransition blockTransition;
+    DepositQueueTransition depositQueueTransition;
+    bytes32 withdrawalQueueHash;
+    uint64 withdrawalBatchIndex;
+}
+
 struct TokenConfig {
     bool enabled;
     bool depositsActive;