Railyard
The AI settlement + model rail.
Thesis
The durable asset is the settlement rail underneath every app: Mint (a fiat-backed, gasless, success-only microdollar ledger with hash-linked receipts, AITP-402). Every other app is either the model rail (Relay) or a wedge that installs Mint under a new class of payer.
The rail
| App | Role | Status |
|---|---|---|
| mint | Settlement ledger — double-entry, Ed25519 receipts, reserve conservation. The core asset. | ship-ready core |
| relay | Model gateway (TensorZero fork) + success-only Mint billing. The model rail. | needs price catalog |
| agent-runtime | Shared Rig/AITP-402 runtime: policy signing, paid SSE/multipart, cancellation reconciliation, pinned Mint-proof verification. | payment SDK ready |
| vend | Stripe-meets-OpenRouter: resellable metered AI SDK on the rail. | needs crash reaper |
| abacus | Inline proxy enforcing hard, receipted per-agent spend budgets (kill-switch). | single-process |
| turnstile | Drop-in agent paywall middleware ("Stripe for AI agents"). | durable paywall core + Axum adapter |
| identity-lock | Provider-agnostic locked character/brand/persona identity, resolved through Relay for consistent generation. Legacy source path: apps/context-passport. | runnable Sx0 |
| ledgerline | Gross-margin lens: revenue + provider COGS on one Mint-backed ledger. | non-atomic settle |
Consumed by, not owned by
Products such as Menivor call Railyard over HTTP and shared contract packages — they do not own it. That separation is the point: the rail outlives any single app.
How a request moves through the rail
A product sends a model request through Relay, the shared model gateway. Agent Runtime carries the signed policy, streaming response, cancellation handling, and Mint receipt verification. Mint records the successful usage as a microdollar ledger entry instead of asking every product to invent its own balance system. Turnstile can expose the same settlement path as paywall middleware, while Abacus applies receipted per-agent spending limits.
This split keeps model routing, payment evidence, and product interfaces separate. A client can change its user experience without replacing the ledger, and the gateway can add providers without moving settlement logic into each application. Hash-linked receipts and reserve-conservation checks make charges inspectable; success-only billing means the rail is designed to capture completed work rather than failed attempts.
Current scope and constraints
Railyard is infrastructure in active development, not a promise that every listed service is production-complete. Mint has a ship-ready core, Agent Runtime has a payment SDK, and Turnstile has its durable paywall core and Axum adapter. Relay still needs a per-model price catalog, Vend needs crash recovery, Abacus is currently single-process, and Ledgerline still needs atomic settlement compensation. The status table above is the source of truth for those boundaries.
Contact
Infra enquiries: caelum0x42@gmail.com.