diff --git a/src/contracts/Cash.kt b/src/contracts/Cash.kt
index 2fc207c7e7..45484d3446 100644
--- a/src/contracts/Cash.kt
+++ b/src/contracts/Cash.kt
@@ -7,6 +7,11 @@ import java.time.Instant
 /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 //
 // Cash
+//
+// Open issues:
+//  - Cannot do currency exchanges this way, as the contract insists that there be a single currency involved!
+//  - Nothing ensures cash states are not created out of thin air.
+//  - Complex logic to do grouping: can it be generalised out into platform code?
 
 // Just a fake program identifier for now. In a real system it could be, for instance, the hash of the program bytecode.
 val CASH_PROGRAM_ID = SecureHash.sha256("cash")
diff --git a/src/core/Main.kt b/src/core/Main.kt
index 29ce357fcf..7a6337482d 100644
--- a/src/core/Main.kt
+++ b/src/core/Main.kt
@@ -1,7 +1,9 @@
 package core
 
+// TODO: Implement transaction processing logic first pass (selection of contract types to run). Ensure that outputs are all accounted for.
+//
 // TODO: Make a decision on basic timestamping approach (use external TSAs? use fake TSA?)
-// TODO: Think about how to expose time to the contract
 // TODO: Pick a serialisation solution for the prototype (kryo?)
 // TODO: Store transactions to a database, design some conflict detection and rollback
-// TODO: Implement a basic UI that shows contracts and very basic network layer (with chat?)
\ No newline at end of file
+// TODO: Implement a basic UI that shows contracts and very basic network layer (with chat?)
+
diff --git a/src/core/Structures.kt b/src/core/Structures.kt
index 36460167aa..42b5ab60c4 100644
--- a/src/core/Structures.kt
+++ b/src/core/Structures.kt
@@ -94,6 +94,7 @@ interface Contract {
     /** Must throw an exception if there's a problem that should prevent state transition. */
     fun verify(inStates: List<ContractState>, outStates: List<ContractState>, args: List<VerifiedSigned<Command>>, time: Instant)
 
+    // TODO: This should probably be a hash of a document, rather than a URL to it.
     /** Unparsed reference to the natural language contract that this code is supposed to express (usually a URL). */
     val legalContractReference: String
 }