Note Changes

The note system has been redesigned. NoteMetadata no longer stores aux or NoteExecutionHint — use NoteAttachment instead.

Quick Fix

src/note.rs

// Before
let metadata = NoteMetadata::new(sender, note_type, tag, execution_hint, aux)?;

// After
let attachment_word = Word::from([aux, execution_hint.into(), felt!(0), felt!(0)]);
let attachment = NoteAttachment::new_word(NoteAttachmentScheme::none(), attachment_word);
let metadata = NoteMetadata::new(sender, note_type)
    .with_tag(tag)
    .with_attachment(attachment);
let note = Note::new(assets, metadata, recipient);

---

Note Attachments

NoteMetadata no longer stores aux or NoteExecutionHint. Use NoteAttachment instead.

src/note.rs

- // Before: aux and hints in metadata
- let metadata = NoteMetadata::new(
-     sender,
-     note_type,
-     tag,
-     execution_hint,         // No longer here
-     aux,                    // No longer here
- )?;

+ // After: use attachments
+ let attachment_word = Word::from([aux, execution_hint.into(), felt!(0), felt!(0)]);
+ let attachment = NoteAttachment::new_word(NoteAttachmentScheme::none(), attachment_word);
+ let metadata = NoteMetadata::new(sender, note_type)
+     .with_tag(tag)
+     .with_attachment(attachment);
+ let note = Note::new(assets, metadata, recipient);

This separation makes note metadata more lightweight and allows attachments to be optional.

---

Tag Semantics

NoteTag::from_account_id was removed. Use NoteTag::new() for explicit values and NoteTag::with_account_target() for account targeting:

src/note.rs

- // Before: tag with embedded target
- let tag = NoteTag::from_account_id(target_account);
-
+ // After: use tag constructors
+ let tag = NoteTag::new(12345);
+ let target_tag = NoteTag::with_account_target(target_account);
+ let metadata = metadata.with_tag(target_tag);

---

Network Account Target

Implement NetworkAccountTarget attachment for network-account notes:

src/network_note.rs

use miden_protocol::note::NoteAttachment;
use miden_standards::note::NetworkAccountTarget;

let target = NetworkAccountTarget::new(account_id, execution_hint)?;
let attachment = NoteAttachment::from(target);
let metadata = metadata.with_attachment(attachment);

---

MINT Notes

MintNoteStorage supports private and public output notes:

src/mint.rs

- // Before
- use miden_lib::note::create_mint_note;
- let mint_note = create_mint_note(
-     faucet_id,
-     sender,
-     recipient_digest,
-     output_note_tag,
-     amount,
-     aux,
-     output_note_aux,
-     rng,
- )?;

+ // After: explicit private/public choice
+ use miden_standards::note::{MintNote, MintNoteStorage};
+ use miden_protocol::note::NoteAttachment;
+
+ // For private output notes
+ let mint_storage = MintNoteStorage::new_private(recipient_digest, amount, output_note_tag);
+
+ // For public output notes
+ let mint_storage = MintNoteStorage::new_public(recipient, amount, output_note_tag)?;
+ let mint_note = MintNote::create(
+     faucet_id,
+     sender,
+     mint_storage,
+     NoteAttachment::default(),
+     rng,
+ )?;

Choose MintNoteStorage::new_private for most use cases. Use new_public only when the note contents should be visible on-chain.

---

Input Notes API

Unified interface accepts full Note objects instead of IDs:

src/transaction.rs

- // Before: separate authenticated/unauthenticated lists
- let tx = TransactionRequestBuilder::new()
-     .with_authenticated_input_notes(auth_note_ids)
-     .with_unauthenticated_input_notes(unauth_note_ids)
-     .build()?;

+ // After: unified input notes
+ let tx = TransactionRequestBuilder::new()
+     .input_notes(notes) // Full Note objects
+     .build()?;

---

FetchedNote Structure

Private notes now carry NoteHeader; public notes expose note and inclusionProof:

src/fetch.rs

match fetched_note {
    FetchedNote::Private(header, _) => {
        // Access header fields
        let note_id = header.id();
    }
    FetchedNote::Public(note, inclusion_proof) => {
        // Access full note and proof
        let inputs = note.inputs();
    }
}

---

Migration Steps

1. Remove aux and execution_hint from NoteMetadata constructors
2. Create NoteAttachment objects for aux data and hints
3. Update NoteTag usage to NoteTag::new() / NoteTag::with_account_target()
4. Use with_account_target() for targeted notes
5. Implement NetworkAccountTarget for network notes
6. Update mint note creation to use MintNoteStorage
7. Refactor input notes to pass full Note objects
8. Update FetchedNote handling for new structure

---

Common Errors

Error	Cause	Fix
NoteMetadata::new takes 2 arguments	aux/hint removed	Use NoteAttachment
NoteTag::from_account_id not found	API changed	Use with_account_target()
with_authenticated_input_notes not found	API unified	Use with_input_notes()