diff --git a/circuits/BatchTreeUpdate.circom b/circuits/BatchTreeUpdate.circom
index 59b98e2..ceb035b 100644
--- a/circuits/BatchTreeUpdate.circom
+++ b/circuits/BatchTreeUpdate.circom
@@ -3,6 +3,7 @@ include "../node_modules/circomlib/circuits/bitify.circom";
 include "./MerkleTreeUpdater.circom";
 include "./TreeUpdateArgsHasher.circom";
 
+// Computes hashes of the next tree layer
 template TreeLayer(height) {
   var nItems = 1 << height;
   signal input ins[nItems * 2];
@@ -19,6 +20,7 @@ template TreeLayer(height) {
 
 // Inserts a leaf batch into a tree
 // Checks that tree previously contained zero leaves in the same position
+// Hashes leaves with Poseidon hash
 template BatchTreeUpdate(levels, batchLevels, zeroBatchLeaf) {
   var height = levels - batchLevels;
   var nLeaves = 1 << batchLevels;
diff --git a/circuits/TreeUpdateArgsHasher.circom b/circuits/TreeUpdateArgsHasher.circom
index 13d11fb..4fb7eb0 100644
--- a/circuits/TreeUpdateArgsHasher.circom
+++ b/circuits/TreeUpdateArgsHasher.circom
@@ -1,13 +1,15 @@
 include "../node_modules/circomlib/circuits/bitify.circom";
 include "../node_modules/circomlib/circuits/sha256/sha256.circom";
 
+// Computes a SHA256 hash of all inputs packed into a byte array
+// Field elements are padded to 256 bits with zeroes
 template TreeUpdateArgsHasher(nLeaves) {
-    signal private input oldRoot;
-    signal private input newRoot;
-    signal private input pathIndices;
-    signal private input instances[nLeaves];
-    signal private input hashes[nLeaves];
-    signal private input blocks[nLeaves];
+    signal input oldRoot;
+    signal input newRoot;
+    signal input pathIndices;
+    signal input instances[nLeaves];
+    signal input hashes[nLeaves];
+    signal input blocks[nLeaves];
     signal output out;
 
     var header = 256 + 256 + 32;
diff --git a/contracts/TornadoTrees.sol b/contracts/TornadoTrees.sol
index 5452b68..06671ca 100644
--- a/contracts/TornadoTrees.sol
+++ b/contracts/TornadoTrees.sol
@@ -100,6 +100,7 @@ contract TornadoTrees is Initializable {
     withdrawalsLength = withdrawalsV1Length;
   }
 
+  /// @dev Queue a new deposit data to be inserted into a merkle tree
   function registerDeposit(address _instance, bytes32 _commitment) public onlyTornadoProxy {
     uint256 _depositsLength = depositsLength;
     deposits[_depositsLength] = keccak256(abi.encode(_instance, _commitment, blockNumber()));
@@ -107,6 +108,7 @@ contract TornadoTrees is Initializable {
     depositsLength = _depositsLength + 1;
   }
 
+  /// @dev Queue a new withdrawal data to be inserted into a merkle tree
   function registerWithdrawal(address _instance, bytes32 _nullifierHash) public onlyTornadoProxy {
     uint256 _withdrawalsLength = withdrawalsLength;
     withdrawals[_withdrawalsLength] = keccak256(abi.encode(_instance, _nullifierHash, blockNumber()));
@@ -114,6 +116,13 @@ contract TornadoTrees is Initializable {
     withdrawalsLength = _withdrawalsLength + 1;
   }
 
+  /// @dev Insert a full batch of queued deposits into a merkle tree
+  /// @param _proof A snark proof that elements were inserted correctly
+  /// @param _argsHash A hash of snark inputs
+  /// @param _argsHash Current merkle tree root
+  /// @param _newRoot Updated merkle tree root
+  /// @param _pathIndices Merkle path to inserted batch
+  /// @param _events A batch of inserted events (leaves)
   function updateDepositTree(
     bytes calldata _proof,
     bytes32 _argsHash,
@@ -158,6 +167,13 @@ contract TornadoTrees is Initializable {
     lastProcessedDepositLeaf = offset + CHUNK_SIZE;
   }
 
+  /// @dev Insert a full batch of queued withdrawals into a merkle tree
+  /// @param _proof A snark proof that elements were inserted correctly
+  /// @param _argsHash A hash of snark inputs
+  /// @param _argsHash Current merkle tree root
+  /// @param _newRoot Updated merkle tree root
+  /// @param _pathIndices Merkle path to inserted batch
+  /// @param _events A batch of inserted events (leaves)
   function updateWithdrawalTree(
     bytes calldata _proof,
     bytes32 _argsHash,