Notes vs Tokens: Why Bearer Instruments Matter for Agents
Ergo has native tokens — fungible assets you can mint, transfer, and burn. It also has Notes — programmable bearer instruments backed by a Reserve with acceptance conditions and expiry. For most uses, tokens are fine. For agent payment pipelines, Notes are the right tool. This post explains exactly why — and when to use each.
TL;DR
Tokens: Fungible Ownership Assets
Native Ergo tokens are first-class citizens in the eUTXO model. No ERC-20 wrapper needed. Transferred by including in a transaction output — but no expiry, no acceptance conditions.
Notes: Programmable Bearer Instruments
Notes are UTxOs with a spending script (acceptance predicate) and registers encoding a credit claim against a specific Reserve. They carry expiry and programmable conditions.
Notes Are Right for Agent Pipelines
Task-conditional payments, multi-step budgets, deferred settlement, and issuer-controlled credit systems require Notes. Tokens can't encode acceptance conditions or expiry.
Notes and Tokens Compose
Notes and tokens don't compete — they work together in the same transaction. Notes handle the payment layer. Tokens handle the ownership layer. ErgoScript makes them interoperable.
Tokens: What They Are
Ergo native tokens are first-class citizens in the eUTXO model. No ERC-20 wrapper, no separate contract — they live directly in UTxOs alongside ERG.
Minted in any transaction — just declare a new token ID
Fungible: 1 unit of token X = 1 unit of token X, always
Transferred by including in a transaction output
Spent exactly once per UTxO — eUTXO model handles double-spend
Can pay transaction fees via Babel Fees
No expiry, no acceptance conditions, no reserve backing by default
Notes: What They Are
Notes are a higher-level concept built on top of eUTXO. They're UTxOs with a specific structure — a spending script (acceptance predicate) and registers encoding credit claim data.
Reference a Reserve box by ID (R4) — the backing collateral
Carry an expiry block height (R5) — void after deadline
Optionally carry an acceptance predicate (R6+) — task hash, credential, etc.
Transferred between agents as payment instruments
Redeemed against Reserve at settlement — Reserve pays out ERG
Tracker prevents double-redemption of the same Note
Key insight: a Note is not a token. It's a credit claim — a promise backed by a specific Reserve, with conditions. The economic analogy is a cheque (bearer instrument) rather than cash (token).
The Key Differences
| Property | Note | Token |
|---|---|---|
| What it represents | A credit claim against a specific Reserve | Ownership of a fungible asset |
| Settlement model | Deferred redemption against Reserve | Transfer of ownership on-chain |
| Acceptance conditions | Programmable — any ErgoScript condition | None — transfer is unconditional |
| Expiry | Yes — HEIGHT < expiry enforced in script | None — exists until spent or burned |
| Reserve backing | Always — Note references specific Reserve | None (or separate stablecoin mechanism) |
| Double-spend protection | eUTXO model + Tracker registry | eUTXO model (UTxO spent once) |
| Micropayment suitability | Yes (same tx cost) | Yes (same tx cost) |
| Multi-agent pipelines | Native — conditions + expiry built in | Works but no expiry/conditions |
| Privacy via ZK | Possible with Sigma Protocols | Possible with Sigma Protocols |
| Gas payment (Babel Fees) | Yes — any token | Yes — any token |
When Agents Need Notes, Not Tokens
Task-conditional payments
You want to pay Agent B only if they produce a specific output. Tokens can't encode 'accept only if blake2b256(output) == X.' Notes can.
Multi-step pipelines with budgets
Orchestrator issues a budget to sub-agents. Each sub-agent has a spending limit and a deadline. Notes carry these constraints natively — tokens don't.
Deferred settlement
Agent B accumulates Notes from multiple payers throughout the day, then redeems them in a single batch transaction against the Reserve. Tokens would require individual transfers.
Credit systems with issuer control
The issuer (orchestrator) needs to be able to limit total outstanding credit. The Reserve contract enforces total issued Notes ≤ reserve value. No equivalent for tokens.
When Tokens Are the Right Tool
Simple unconditional payments
Pay Agent B 10 units of token X — no conditions, no expiry. Just transfer. Tokens are simpler and more efficient for this.
Governance and staking
Voting rights, staking positions, protocol ownership — these are ownership claims that don't expire and don't need acceptance conditions. Use tokens.
NFTs and unique assets
Non-fungible items are tokens with quantity 1. Notes are always fungible bearer instruments. For unique digital assets, use tokens.
Long-lived liquidity positions
LP tokens in a DEX represent a share of a liquidity pool indefinitely. Notes expire. Wrong tool for long-lived positions.
The Composability Argument
Notes and tokens don't compete — they compose. A real agent economy application uses both.
Orchestrator holds ERG in a Reserve → issues Notes to sub-agents
Sub-agents hold Notes as spendable credit → pay services with Notes
Service providers accumulate Notes → redeem for ERG from Reserve
Service providers receive governance tokens as bonus → hold or trade
Governance token holders → vote on Reserve parameters with token weight
The primitives are orthogonal and composable. Notes handle the payment layer. Tokens handle the ownership layer. ErgoScript makes them interoperable in the same transaction.
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