\r \r

a2a-Market Compute Ledger\r

\r Build and operate the compute ledger module for RealMarket A2A runtime.\r \r Current status: scaffold-first skill for early registration. Keep APIs stable, add production logic incrementally.\r \r

Scope\r

• Own ComputeAccount domain object, balance snapshots, and immutable transaction journal.\r
• Support reserve/freeze before negotiation and final debit after order confirmation.\r
• Emit billing events to event bus for reputation, websocket push, and finance logs.\r \r

Suggested Project Layout\r

• app/domain/entities/compute_account.py\r
• app/application/services/billing_service.py\r
• app/infrastructure/db/ledger_repository.py\r
• app/infrastructure/tasks/reconcile_ledger.py\r \r

Minimum Contracts (MVP P0)\r

1. freeze(account_id, amount, reason) returns hold id and expiry.\r
2. capture_hold(hold_id, order_id) converts hold to settled charge.\r
3. release_hold(hold_id) unlocks unused balance.\r
4. list_ledger_entries(account_id, from_ts, to_ts) returns ordered journal records.\r \r

Event Mapping\r

• On hold created: emit INTENT_CREATED + billing extension payload.\r
• On charge captured: emit ORDER_CREATED and settlement payload.\r
• On charge finalized: emit PAYMENT_SUCCEEDED.\r \r

Guardrails\r

• Use integer minor units for money; avoid float math.\r
• Enforce idempotency key on every mutating operation.\r
• Keep journal append-only; never rewrite posted entries.\r \r

Implementation Backlog\r

• Add double-entry validation rules.\r
• Add monthly statement export and audit tooling.\r \r

Runtime Implementation\r

• Status: implemented in local runtime package.\r
• Primary code paths:\r
• runtime/src/domain/compute-ledger.js\r
• Validation: covered by runtime/tests and npm test in runtime/.\r