# Coulomb MVP — Liquidity & Cost Requirements

## Context

Coulomb Social carries **operator infrastructure costs** (domains, virtual
servers, payment-processing fees, future OpenRouter usage) while **customer
cost-pass-through billing is not active yet**. Members pay a flat subscription; they are not billed for
underlying platform spend.

The Economic Observatory must make the resulting **liquidity burn** visible.

## Requirements

### LQ-001 — Expense record ledger (source of truth)

Capture every operator expense as an individual record in
`data/expense_records.json`. Fields: `period`, `vendor`, `amount`, `currency`,
`cost_class`, `source`.

**Never store hand-calculated monthly or cumulative totals in data files.**
All aggregations must be computed programmatically by `observatory/ledger.py`.

### LQ-002 — Payment record ledger

Capture member subscription payments in `data/payment_records.json` with gross,
fees, and net amounts per period. Payment-processing totals are summed from
`fees_amount` — not duplicated as expense records.

### LQ-003 — Budget tracking

Maintain an operator liquidity budget (initial: **€1,000**) and compute
remaining budget after cumulative **infrastructure** spend minus cumulative net
member payments received.

### LQ-004 — Liquidity position

Report whether the project is **burning**, **neutral**, or **generating**
liquidity each period:

- `period_net = net_member_payments - infrastructure_cost`
- `cumulative_net = sum(period_net)`
- `remaining_budget = initial_budget + cumulative_net`

**No double-counting:** payment-processing fees are deducted from net member
payments. They are summed separately for economics reporting but must **not** be
subtracted again in the liquidity formula.

- `total_platform_cost = infrastructure_cost + payment_processing_cost` (for
  gross-margin economics vs gross revenue)
- `cumulative_total_platform_cost` is informational; liquidity burn uses
  `cumulative_infrastructure_cost` only

### LQ-005 — No customer cost billing (MVP boundary)

Do not allocate platform costs to customer invoices in MVP. Cost attribution
(OpenRouter per member, usage overage) is observatory-only until a later phase
introduces customer-visible credits or usage billing.

### LQ-006 — Historical dashboard

Economics Dashboard must show:

- Current-period economics (revenue, platform cost, margin)
- Cumulative liquidity summary (budget, burn, remaining)
- Monthly history table computed from ledgers

### LQ-007 — Deterministic calculation engine

All economics and liquidity figures must be produced by the Python observatory
package (`ledger.py`, `economics.py`). LLM or manual arithmetic must not be the
source of aggregated totals.

## Data sources (current)

| Ledger | Path |
|--------|------|
| Budget | `data/budget.json` |
| Expense records | `data/expense_records.json` |
| Payment records | `data/payment_records.json` |
| Membership | `data/membership.json` |

Future sprints replace manual records with Bubble, Stripe, and OpenRouter imports
while preserving the same ledger schema and calculation rules.