BRC-175: 1Sat Fungible Basket Profile

SUMMARY.md

@@ -120,6 +120,7 @@
 * [1Sat Provenance Remittance for Basket `1sat`](./tokens/0150.md)
 * [1Sat Ordinals — Single-Satoshi Tokens and Origin Tracking](./tokens/0159.md)
 * [1Sat Ordinals — Inscription Envelopes](./tokens/0160.md)
+* [1Sat Fungible Basket Profile for BRC-46 / BRC-100](./tokens/0175.md)
 * [Miner-Enforced Resale-Royalty Covenant Tokens (OP_PUSH_TX)](./tokens/0226.md)
 
 ## Overlays

tokens/0147.md

@@ -213,11 +213,13 @@ Normative fine-grained asset permission schemes remain [BRC-99](../wallet/0099.m
 * Wallets that do not implement this profile MUST still store and forward unknown baskets’ `customInstructions` and tags unchanged ([BRC-37](../outpoints/0037.md)).
 * This profile does not conflict with BRC-99 `p ` baskets; future permission-wrapped variants MAY wrap `1sat` semantics under a `p <scheme> …` name without invalidating this profile for the plain `1sat` basket.
 * Marketplaces (e.g. OrdLock), BSV-20/21, and mint APIs are out of scope.
+* **[BRC-175](./0175.md) fungibles** share the bare P2PKH tip-move shape with this profile. Chain-scan / instant-ingest MUST NOT place an output in basket `1sat` solely because its creating transaction spends a 1-sat input. Importers SHOULD require an inscribed non–`1sat-ft` ancestor (or equivalent remittance / provenance) before painting a collectable. An ancestor with content-type `application/1sat-ft+json` MUST NOT yield eligibility for this profile.
 
 ## Security considerations
 
 * **Tag / metadata spoofing** — Without provenance verification, a sender can attach another inscription’s `origin` and `name`. See [BRC-150](./0150.md). A forged `content` only mis-points display media; it does not prove tip→origin.
 * **Basket pollution** — Placing non-1-sat or non-ordinal outputs in `1sat` confuses list UIs; receivers should re-check `satoshis` and inscription rules.
+* **Fungible misfile** — Auto-importing every bare 1-sat that spends a 1-sat parent will file [BRC-175](./0175.md) transfer tips into `1sat`. Those tips then look burnable as junk NFTs. See Compatibility above.
 * **Burn** — Per 1Sat Ordinals, packing a sat into a multi-sat output ends that origin trail. Do not continue `origin:` claims across a burn.
 * **Indexer trust** — Display media URLs and collection metadata often come from indexers; this profile does not make indexers authoritative for tip→origin binding. Forwarding `content` reduces indexer dependence for derivative media.
 

tokens/0175.md

@@ -0,0 +1,266 @@
+# BRC-175: 1Sat Fungible Basket Profile for BRC-46 / BRC-100
+
+Brandon Cryderman / HandCash (brandongcryderman@gmail.com)
+
+## Abstract
+
+This BRC defines the **fungible** application basket profile for 1Sat under [BRC-46](../wallet/0046.md) / [BRC-100](../wallet/0100.md). A fungible 1Sat token is a set of **1-satoshi tips that share one origin**. Token identity is that origin outpoint. Each tip carries a face value **`amt`** (token units). **Balance** is the sum of `amt` on bound tips held. Transfers **spend tip UTXOs and create new 1-sat tips** (recipients and change), funded with ordinary BSV dust — the same custody class as collectables ([BRC-147](./0147.md)), not a split of one physical satoshi across payees.
+
+**Locked supply is optional:** the origin MAY set `supply: "locked"` with `max` (**total units**). When omitted, tips still bind via tip→origin rules with face-value `amt`; wallets MUST NOT invent a lock. Offline tip→origin proof reuses [BRC-150](./0150.md). Mint-batch attestation MAY bind same-tx genesis siblings until a transfer creates a 150 path. A tip with omitted `amt` MUST be treated as `amt = 1` (tip-count legacy).
+
+This BRC does not redefine 1Sat origin theory ([BRC-159](./0159.md)) or inscription envelopes ([BRC-160](./0160.md)).
+
+## Motivation
+
+Collectables already interoperate as tip→origin assets with offline proof ([BRC-147](./0147.md), [BRC-150](./0150.md)). Fungible balances that re-inscribe protocol JSON each hop do not share that transfer path and typically depend on indexers for discovery and settlement. Counting tips as units (without face-value `amt`) does not scale: moving *N* units costs *O(N)* tips.
+
+Wallets and future **token markets** need a shared contract so that:
+
+1. Markets and wallets identify a token by **origin** (one id forever).
+2. Inventory is a set of **tip UTXOs** (listable, lockable, settleable like collectables).
+3. Large balances MAY sit in **one tip** (`amt` large); sends **split/merge** with change.
+4. Fungible tips are not filed into NFT basket `1sat`.
+5. Supply policy is readable from the **origin tip** without an indexer census.
+6. Custody never depends on a market overlay or indexer being online.
+
+## Specification
+
+### Basket identifier
+
+* The storage basket name is the UTF-8 string `1sat-ft`.
+* After [BRC-46](../wallet/0046.md) normalization (trim + lowercase), conforming use MUST use exactly `1sat-ft`.
+* This identifier does **not** use the [BRC-99](../wallet/0099.md) `p ` prefix.
+* Outputs for this profile MUST NOT be placed in basket `1sat` ([BRC-147](./0147.md)).
+* Writers and readers MUST use `1sat-ft` (no legacy basket alias).
+
+### Eligibility
+
+An output SHOULD be placed in basket `1sat-ft` only when **all** hold:
+
+1. `satoshis === 1`.
+2. The tip is a carrier for fungible units of a token whose identity is a shared origin outpoint.
+3. The tip **binds** to that origin under §Binding (below).
+4. The tip carries a valid first `ord` envelope ([BRC-160](./0160.md)). Genesis and mint-batch tips MUST. **New transfer colour tips MUST** (see §Transfer inscription). Legacy bare leftovers MAY exist; they bind only via lineage walk and MUST NOT invent `amt`.
+
+Wallets MUST NOT place ordinary payment change or multi-sat outputs into `1sat-ft`.  
+**Autodetect is not “any 1-sat output”:** `satoshis === 1` is necessary; basket + binding are required before counting units.
+
+### Token identity and units
+
+* **Token id** = origin outpoint (`txid_vout` after normalize; same rules as [BRC-147](./0147.md)).
+* **Carrier** = 1-sat tip UTXO. Face value is **not** the satoshi amount.
+* **`amt`** = positive integer token units on that tip (decimal string in JSON).
+* **Balance** = sum of `amt` over bound tips held for that origin.
+* Missing `amt` ⇒ treat as `"1"` (legacy tip-count rows).
+* **`max`** (locked) = total units at genesis, **not** required tip count.
+* **Decimals** — Origin MAY reserve `dec`; readers that do not implement decimals MUST treat `amt` as integer units and MUST NOT invent fractional balances.
+
+### Origin inscription (normative policy surface)
+
+The **origin tip** (outpoint = token id) MUST carry an `ord` envelope whose body is UTF-8 JSON:
+
+```json
+{
+  "p": "1sat-ft",
+  "v": 1,
+  "amt": "1000",
+  "sym": "GOLD",
+  "name": "optional",
+  "supply": "locked",
+  "max": "1000"
+}
+```
+
+| Field | Requirement | Meaning |
+|-------|-------------|---------|
+| `p` | MUST | Profile id `1sat-ft`. |
+| `v` | MUST | Origin schema version. This BRC defines `1`. |
+| `amt` | MUST | Face value of **this** tip (genesis tip often holds the full issued amount). |
+| `supply` | MAY | `locked` freezes total units. Omit when no cap. `open` means uncapped (no local max). |
+| `max` | MUST when `supply` is `locked` | Total units. Decimal string of a positive integer. |
+| `sym` | SHOULD | Short symbol (≤ 32). |
+| `name` | MAY | Display name (≤ 80). |
+| `dec` | RESERVED | Future decimal places; ignore if unimplemented. |
+| `issuer` / `auth` | RESERVED | Future open-mint authority; ignore until defined. |
+
+Unknown fields MUST be preserved by wallets that round-trip remittance ([BRC-37](../outpoints/0037.md) spirit) and MUST be ignored for validation unless this BRC defines them.
+
+**Authority:** When locked, the origin inscription is the sole durable supply policy. Remittance MUST NOT contradict it (`supply` / `max` on tips SHOULD echo the origin when present; on conflict, **origin wins**). Wallets MUST NOT write `supply: locked` unless the origin defined it. Child tips MUST NOT claim `amt` that violates §Conservation.
+
+### Supply (optional lock)
+
+| State | Meaning |
+|-------|---------|
+| *(omitted)* / `open` | No declared unit cap. Hold/send still use `amt` + binding + conservation. |
+| `locked` | Genesis defines total units `max`. No further mint against this origin. |
+
+Conforming **locked mints** MUST:
+
+1. Create one or more 1-sat tips in the genesis transaction whose **`amt` values sum to `max`**, and
+2. Set origin `supply` to `locked` with that `max`.
+
+A single genesis tip with `amt = max` is the preferred compact locked mint. Unlocked mints MAY omit `supply`/`max` and issue any positive genesis `amt`.
+
+Conforming **receivers** MUST accept a tip only if it binds under §Binding. When the origin is locked, mint-batch / local holdings MUST respect `max`. Holders are **not** required to enumerate global circulating supply via an indexer. Markets MAY show indexer stats as convenience only (grade C).
+
+### Mint batch (genesis siblings)
+
+Optional. Genesis MAY create the origin tip and additional siblings in the **same transaction** (`randomizeOutputs: false` recommended so origin is `txid_0`).
+
+Sibling at `txid_vout` binds when:
+
+* same txid as origin,
+* remittance includes `"mint": { "batch": true, "vout": <vout> }`,
+* `origin` matches the genesis origin outpoint,
+* each sibling has a positive `amt`,
+* sum of all genesis tip `amt` values equals origin `max`, and
+* each output is 1 sat with a valid first `ord` envelope on genesis outputs.
+
+After the first transfer of a tip, senders SHOULD attach [BRC-150](./0150.md) provenance; receivers MUST prefer a verifying 150 package over mint-batch attestation alone.
+
+### Conservation (split / merge)
+
+Token units are conserved across spends:
+
+1. Select one or more **input tips** bound to the same origin.
+2. Let `S` = sum of input `amt`.
+3. Create one or more **output tips** (1 sat each), funded with ordinary BSV for dust + fees.
+4. Let `T` = sum of output `amt` for that origin in the same action.
+5. Receivers / wallets MUST require `T === S`. Change is an output tip back to the sender (or another allowed destination) with the residual `amt`.
+
+There is **no** requirement that one physical satoshi be “split” among recipients. The input tip UTXO(s) are spent; new 1-sat carriers are created. Multi-recipient pays = multiple new tips in one (or more) transactions.
+
+Merging (many inputs → fewer outputs) and splitting (few inputs → more outputs) use the same conservation rule.
+
+### Binding (when a tip counts)
+
+A tip **binds** to origin `O` if any of the following hold (checked in order):
+
+1. **Genesis** — tip outpoint equals `O`, and origin inscription parses as this profile.
+2. **Transfer inscription** — this tip’s first `ord` envelope is `application/1sat-ft+json` with a positive integer `amt`, and the spend-chain / BRC-150 walk binds to `O`. `amt` is taken from this envelope.
+3. **BRC-150** — `customInstructions.provenance` verifies per [BRC-150](./0150.md) v2 to origin `O`.
+4. **Mint batch** — same-tx sibling attestation as above.
+5. **Parent hop** — remittance `parent` names a tip that itself binds to `O` (inductive), and this tip’s `amt` is consistent with a conserving spend of that parent (wallets SHOULD verify when parent spend data is available). Wallets MUST depth-limit inductive walks and MUST fail closed on cycles, missing parents, or parents that do not themselves bind. A `parent` claim alone MUST NOT bind.
+
+`mint.extend` without a future auth rule does **not** bind.
+
+### Tags
+
+| Tag | Requirement | Meaning |
+|-----|-------------|---------|
+| `1sat-ft` | SHOULD | Profile marker. |
+| `ordinal` | SHOULD | 1-sat ordinal tip. |
+| `origin:<outpoint>` | SHOULD when known | Claimed origin. |
+| `name:<string>` / `sym:<string>` | MAY | Display claims. |
+| `id:` / `outid:` | SHOULD for held rows | Local list key ([BRC-164](../wallet/0164.md) practice). |
+
+Unknown tags MUST be preserved.
+
+### Custom instructions (per tip)
+
+```json
+{
+  "p": "1sat-ft",
+  "origin": "<txid_vout>",
+  "amt": "400",
+  "sym": "<optional echo>",
+  "supply": "locked",
+  "max": "<echo when locked>",
+  "mint": { "batch": true, "vout": 3 },
+  "parent": "<optional prior tip>",
+  "provenance": { }
+}
+```
+
+| Field | Requirement | Meaning |
+|-------|-------------|---------|
+| `p` / `origin` | SHOULD / MUST when known | Profile + token id. |
+| `amt` | MUST when known | Face value of this tip (decimal string). Omit only for legacy `amt = 1`. |
+| `supply` / `max` | SHOULD when origin locked | Echo origin policy only — do not invent. |
+| `mint` | MAY | Genesis batch attestation. |
+| `parent` | MAY | Prior tip for inductive bind. |
+| `provenance` | SHOULD when buildable | BRC-150 v2 object. |
+
+### Transfer inscription
+
+Conforming senders MUST inscribe each new colour tip (payee and change) as `application/1sat-ft+json` over P2PKH. Body is UTF-8 JSON:
+
+```json
+{
+  "amt": "9000"
+}
+```
+
+| Field | Requirement | Meaning |
+|-------|-------------|---------|
+| `amt` | MUST | Face value of **this** tip (decimal string). |
+
+Origin is **not** written on the leftover. Identity is the spend-chain / [BRC-150](./0150.md) walk to the mint, same as [BRC-147](./0147.md). `amt` is on this tip so a split can be verified before the wallet shows it as true.
+
+Other 1-sat outputs in the same transaction are **not** carriers unless they carry this envelope.
+
+Remittance (`customInstructions`) MAY repeat `origin` + `amt` to speed import, same as 147. When remittance `amt` and the inscription disagree, **the inscription wins**. A tip with no envelope is legacy: scanners MUST walk spend-chain to an inscribed ancestor and MUST NOT invent `amt`.
+
+### Transfer
+
+1. Select input tip(s) bound to the same origin with sufficient Σ `amt`.
+2. Build output tip(s): payee amounts + change; enforce §Conservation.
+3. Spend inputs; create new 1-sat outputs (BSV funds dust + fees).
+4. **Inscribe** each colour tip per §Transfer inscription.
+5. File under basket `1sat-ft` with tags + CI including `amt` (fast path).
+6. Attach BRC-150 when a path exists; else set `parent` to a spent tip and echo origin policy.
+
+### Chain scan and basket separation
+
+Address / UTXO scan MAY surface 1-sat outs. Conforming wallets:
+
+* An output whose own first `ord` envelope is `application/1sat-ft+json` MUST be this profile. Read `amt` from the body. Origin comes from the 150 / spend-chain walk. Remittance is a fast path only.
+* MUST NOT place a 1-sat output in basket `1sat` ([BRC-147](./0147.md)) solely because the creating transaction spends a 1-sat input.
+* MUST NOT place an output in basket `1sat-ft` until it **binds** under §Binding. Unbound 1-sat outs SHOULD be held (not swept, not painted as collectables).
+* When walking legacy bare-tip lineage, an ancestor whose first `ord` envelope content-type is `application/1sat-ft+json` MUST be treated as this profile — not as a collectable mint. Do not invent `amt` for that leftover.
+
+### Peer capability (optional)
+
+Senders MAY advertise support for basket `1sat-ft` / this profile via identity or handle-resolve metadata, and MAY warn or refuse bare-address sends to peers that do not advertise it. Remittance is a fast path for identified peers; the inscription is custody. Capability bits are **not** a custody requirement.
+
+### Provenance scope
+
+The BRC-150 v2 **object schema and verification rules** apply unchanged when present. Conforming wallets MUST accept 150 packages for `1sat-ft` tips. A future BRC-150 errata MAY list basket `1sat-ft` explicitly; until then this BRC imports the format by reference.
+
+### Open mint (reserved)
+
+Post-genesis mint via `mint.extend` is **not binding** without a future **auth** rule on the origin. Uncapped (`supply` omitted / `open`) is not the same as free extend — new tips still need genesis, mint-batch, BRC-150, or a proven parent hop.
+
+### Market / overlay notes (informative)
+
+| Concern | Approach |
+|---------|----------|
+| Token identity in a catalog | Origin outpoint |
+| Seller inventory | Bound tips in `1sat-ft` (UTXOs) with `amt` |
+| Listing lock | Existing OrdLock / marketplace patterns on tip UTXOs |
+| Settlement | Conserving tip spends to buyer (same as wallet send) |
+| Discovery / volume charts | Optional overlays (grade C) — never custody |
+| Scaling | Transfer cost ≈ tips spent/created, not unit count; prefer compact `amt` |
+
+## Security considerations
+
+* **Tag / CI spoofing** — Without binding (§Binding), identity is unproven. Markets MUST NOT treat unproven tips as inventory of origin `O`.
+* **`amt` inflation** — Receivers MUST enforce §Conservation when parent spend data is available; unbound or non-conserving tips MUST NOT increase spendable balance.
+* **Mint-batch weaker than 150** — Prefer 150 after first hop. Genesis envelopes + `max` + Σ `amt` bound the batch.
+* **Locked vs lying minter** — Origin `max` does not stop extra 1-sat outputs on-chain; conforming wallets **reject** tips that do not bind / conserve for that token id.
+* **Open mint** — Deferred precisely because unbounded extend claims are forgeable.
+* **Basket mix-up** — Do not file fungibles into `1sat` or collectables into `1sat-ft`.
+* **Legacy bare leftovers** — Older sends may be bare P2PKH. A bare 1-sat that spends a 1-sat parent is **not** a collectable. Walk lineage; FT mime ancestor ⇒ this profile, and do not invent `amt`. New conforming sends inscribe origin + amt so a scan can read the tip without remittance. Pre–BRC-175 clients that treat unknown `ord` mimes as collectables may still misfile inscribed tips; that is an old-client bug, not a reason to omit the envelope.
+
+## Relationship to other BRCs
+
+| BRC | Relationship |
+|-----|----------------|
+| [BRC-147](./0147.md) | Collectables / NFT basket `1sat`. Remittance is a fast path on both profiles; see §Chain scan. |
+| [BRC-150](./0150.md) | Provenance format for lineage hops. |
+| [BRC-159](./0159.md) / [BRC-160](./0160.md) | Origin theory / envelopes. |
+| [BRC-165](./0165.md) | P1Sat permissions for collectables; fungible scopes MAY follow. |
+
+## Copyright
+
+Copyright (c) Brandon Cryderman / HandCash. Licensed under the Open BSV License.

tokens/README.md

@@ -17,4 +17,5 @@ BRC | Standard
 150  | [1Sat Provenance Remittance for Basket `1sat`](./0150.md)
 159  | [1Sat Ordinals — Single-Satoshi Tokens and Origin Tracking](./0159.md)
 160  | [1Sat Ordinals — Inscription Envelopes](./0160.md)
+175  | [1Sat Fungible Basket Profile for BRC-46 / BRC-100](./0175.md)
 226  | [Miner-Enforced Resale-Royalty Covenant Tokens (OP_PUSH_TX)](./0226.md)