diff --git a/sharding/collation.go b/sharding/collation.go
index 594cf3f2247a..dee3061b6dbd 100644
--- a/sharding/collation.go
+++ b/sharding/collation.go
@@ -35,6 +35,7 @@ func (c *Collation) ProposerSignature() []byte          { return c.header.propos
 func (c *Collation) SetHeader(h *CollationHeader) { c.header = h }
 
 func (c *Collation) AddTransaction(tx *types.Transaction) {
+	// TODO: Check transaction does not exceed gas limit
 	c.transactions = append(c.transactions, tx)
 }