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Commerce: catalog, orders, inventory authority and asynchronous settlement ​

This example is the most involved pattern in the set. It publishes a catalog, accepts guest orders, reserves stock exactly once in an application-owned Durable Object, expires unpaid orders through a Queue with a cron sweep as recovery, and shows where a real payment provider plugs in. Read it if money and stock are involved.

Problem ​

Staff publish products with a price. A guest places an order for one or more products; the server re-prices every line, reserves stock, and returns an order token with a fifteen-minute payment deadline. Payment arrives asynchronously from a provider callback, never from the browser. If payment does not arrive in time the reservation is released. Staff adjust stock, fulfil paid orders and read a picking list, all through Admin or Staff MCP, and every stock change is auditable. Mantle stores the query mirrors; the Durable Object is the only writer of truth for stock.

Manifest ​

Trimmed to the essentials that stay valid together. Localized product copy is omitted; see Publication for the parent/child pattern.

yaml
apiVersion: cms.mantle.aotter.net/v1
kind: Schema
metadata:
  name: products
spec:
  title: Products
  lifecycle: publishing
  uniqueIndexes:
    - [slug]
  schema:
    type: object
    additionalProperties: false
    required: [slug, title, priceMinor, currency]
    properties:
      slug: { type: string, pattern: "^[a-z0-9-]+$" }
      title: { type: string, minLength: 1, maxLength: 160 }
      summary: { type: string, maxLength: 500 }
      priceMinor: { type: integer, minimum: 0, x-mcp-hint: money-minor }
      currency: { type: string, pattern: "^[A-Z]{3}$" }
---
apiVersion: cms.mantle.aotter.net/v1
kind: Schema
metadata:
  name: orders
spec:
  title: Orders
  description: Guest orders created by checkout and maintained only by declared Procedures.
  lifecycle: operational
  uniqueIndexes:
    - [orderToken]
    - [orderNumber]
  indexes:
    - [orderStatus]
  searchableFields: [orderNumber, customerName, customerEmail]
  uiSchema:
    list:
      filterField: orderStatus
      primaryField: orderNumber
      columns: [orderStatus, customerEmail, totalMinor]
  schema:
    readOnly: true
    type: object
    required: [orderToken, orderNumber, orderStatus, currency, totalMinor, customerName, customerEmail, shippingAddress, items, expiresAt]
    properties:
      orderToken: { type: string, pattern: "^[0-9a-f-]{36}$" }
      orderNumber: { type: string }
      orderStatus: { type: string, enum: [pending_payment, paid, fulfilled, cancelled] }
      currency: { type: string, pattern: "^[A-Z]{3}$" }
      totalMinor: { type: integer, minimum: 0, x-mcp-hint: money-minor }
      customerName: { type: string, minLength: 1, maxLength: 120 }
      customerEmail: { type: string, format: email }
      shippingAddress: { type: string, minLength: 1, maxLength: 500 }
      items:
        type: array
        minItems: 1
        maxItems: 20
        items:
          type: object
          required: [productSlug, title, quantity, unitPriceMinor, lineTotalMinor]
          properties:
            productSlug: { type: string }
            title: { type: string }
            quantity: { type: integer, minimum: 1, maximum: 99 }
            unitPriceMinor: { type: integer, minimum: 0 }
            lineTotalMinor: { type: integer, minimum: 0 }
      expiresAt: { type: number, x-mcp-hint: timestamp-ms }
      paidAt: { type: number, x-mcp-hint: timestamp-ms }
      fulfilledAt: { type: number, x-mcp-hint: timestamp-ms }
      cancelledAt: { type: number, x-mcp-hint: timestamp-ms }
      trackingNumber: { type: string }
      cancelReason: { type: string }
---
apiVersion: cms.mantle.aotter.net/v1
kind: Schema
metadata:
  name: inventory
spec:
  title: Inventory
  description: Query mirror of the InventoryCoordinator Durable Object, which is the stock authority.
  lifecycle: operational
  uniqueIndexes:
    - [productSlug]
  indexes:
    - [available, productSlug]
  uiSchema:
    list:
      primaryField: productSlug
      columns: [available, reserved, revision]
    nav:
      standalone: true
      parentField: productSlug
  schema:
    readOnly: true
    type: object
    required: [productSlug, available, reserved, revision]
    properties:
      productSlug: { type: string, x-mantle-ref: products }
      available: { type: integer, minimum: 0 }
      reserved: { type: integer, minimum: 0 }
      revision: { type: integer, minimum: 0 }
---
apiVersion: cms.mantle.aotter.net/v1
kind: Schema
metadata:
  name: inventory-movements
spec:
  title: Inventory movements
  description: Append-only audit trail for stock changes caused by checkout and staff operations.
  lifecycle: operational
  uniqueIndexes:
    - [movementKey]
  indexes:
    - [kind, occurredAt]
    - [productSlug, occurredAt]
    - [orderToken]
  uiSchema:
    list:
      filterField: kind
      primaryField: productSlug
      columns: [kind, availableDelta, reservedDelta, occurredAt]
  schema:
    readOnly: true
    type: object
    required: [movementKey, productSlug, kind, availableDelta, reservedDelta, occurredAt]
    properties:
      movementKey: { type: string }
      productSlug: { type: string }
      orderToken: { type: string }
      kind: { type: string, enum: [adjust, reserve, sale, release, cancellation] }
      availableDelta: { type: integer }
      reservedDelta: { type: integer }
      note: { type: string }
      occurredAt: { type: number, x-mcp-hint: timestamp-ms }
---
apiVersion: cms.mantle.aotter.net/v1
kind: View
metadata:
  name: public-products
spec:
  surface: public
  from: products
  fields: [id, slug, title, summary, priceMinor, currency, updatedAt]
  filter:
    eq: { field: status, value: published }
  orderBy:
    - { field: slug, direction: asc }
  limit: 100
---
apiVersion: cms.mantle.aotter.net/v1
kind: View
metadata:
  name: picking-list
spec:
  title: Picking list
  surface: staff
  uiSchema:
    list:
      columns: [orderNumber, customerName, shippingAddress, productSlug, productTitle, quantity]
      searchFields: [orderNumber, customerName, shippingAddress, productSlug, productTitle]
  sql: |
    SELECT
      o.orderNumber,
      o.customerName,
      o.shippingAddress,
      json_extract(item.value, '$.productSlug') AS productSlug,
      json_extract(item.value, '$.title') AS productTitle,
      json_extract(item.value, '$.quantity') AS quantity
    FROM orders AS o
    JOIN json_each(o.items) AS item
    WHERE o.orderStatus = 'paid'
    ORDER BY o.createdAt ASC, o.orderNumber ASC, item.key ASC
  limit: 200
---
apiVersion: cms.mantle.aotter.net/v1
kind: Procedure
metadata:
  name: place-order
spec:
  input:
    type: object
    additionalProperties: false
    required: [customerName, customerEmail, shippingAddress, items]
    properties:
      customerName: { type: string, minLength: 1, maxLength: 120 }
      customerEmail: { type: string, format: email }
      shippingAddress: { type: string, minLength: 1, maxLength: 500 }
      items:
        type: array
        minItems: 1
        maxItems: 20
        items:
          type: object
          additionalProperties: false
          required: [productSlug, quantity]
          properties:
            productSlug: { type: string, pattern: "^[a-z0-9-]+$" }
            quantity: { type: integer, minimum: 1, maximum: 99 }
  output:
    type: object
    required: [outcome, orderToken, orderNumber, expiresAt, totalMinor, currency]
    properties:
      outcome: { type: string, enum: [pending_payment] }
      orderToken: { type: string }
      orderNumber: { type: string }
      expiresAt: { type: number }
      totalMinor: { type: integer }
      currency: { type: string }
  handler: { kind: ref, ref: placeOrder }
---
apiVersion: cms.mantle.aotter.net/v1
kind: Procedure
metadata:
  name: pay-order
spec:
  input:
    type: object
    additionalProperties: false
    required: [orderToken]
    properties:
      orderToken: { type: string, pattern: "^[0-9a-f-]{36}$" }
  output:
    type: object
    required: [outcome, orderToken]
    properties:
      outcome: { type: string, enum: [paid, already_paid, expired, closed, missing] }
      orderToken: { type: string }
  handler: { kind: ref, ref: payOrder }
---
apiVersion: cms.mantle.aotter.net/v1
kind: Procedure
metadata:
  name: cancel-guest-order
spec:
  input:
    type: object
    additionalProperties: false
    required: [orderToken]
    properties:
      orderToken: { type: string, pattern: "^[0-9a-f-]{36}$" }
  output:
    type: object
    required: [outcome, orderToken]
    properties:
      outcome: { type: string, enum: [cancelled, already_cancelled, closed, missing] }
      orderToken: { type: string }
  handler: { kind: ref, ref: cancelGuestOrder }
---
apiVersion: cms.mantle.aotter.net/v1
kind: Procedure
metadata:
  name: adjust-inventory
spec:
  title: Adjust inventory
  requires:
    auth:
      all:
        - { "ctx.staff": [owner] }
  input:
    type: object
    additionalProperties: false
    required: [operationId, productSlug, delta, reason]
    properties:
      operationId: { type: string, format: uuid, x-mcp-hint: idempotency-key }
      productSlug: { type: string, pattern: "^[a-z0-9-]+$", x-mantle-ref: products }
      delta: { type: integer, minimum: -100000, maximum: 100000 }
      reason: { type: string, minLength: 1, maxLength: 500 }
  uiSchema:
    fields:
      reason: { widget: textarea }
  output:
    type: object
    required: [productSlug, available, reserved, revision]
    properties:
      productSlug: { type: string }
      available: { type: integer }
      reserved: { type: integer }
      revision: { type: integer }
  handler: { kind: ref, ref: adjustInventory }
---
apiVersion: cms.mantle.aotter.net/v1
kind: Procedure
metadata:
  name: fulfill-order
spec:
  title: Fulfill order
  requires:
    auth:
      all:
        - { "ctx.staff": [owner] }
  input:
    type: object
    additionalProperties: false
    required: [orderToken]
    properties:
      orderToken: { type: string, pattern: "^[0-9a-f-]{36}$", x-mantle-ref: orders }
      trackingNumber: { type: string, maxLength: 120 }
  output:
    type: object
    required: [outcome, orderToken]
    properties:
      outcome: { type: string, enum: [fulfilled, already_fulfilled, closed, missing] }
      orderToken: { type: string }
  handler: { kind: ref, ref: fulfillOrder }
---
apiVersion: cms.mantle.aotter.net/v1
kind: Procedure
metadata:
  name: expire-order
spec:
  input:
    type: object
    additionalProperties: false
    required: [orderToken, now]
    properties:
      orderToken: { type: string, pattern: "^[0-9a-f-]{36}$" }
      now: { type: number }
  output:
    type: object
    required: [outcome, orderToken]
    properties:
      outcome: { type: string, enum: [expired, too_early, closed, missing] }
      orderToken: { type: string }
  handler: { kind: ref, ref: expireOrder }
---
apiVersion: cms.mantle.aotter.net/v1
kind: Procedure
metadata:
  name: sweep-expired-orders
spec:
  input:
    type: object
    additionalProperties: false
    required: [now]
    properties:
      now: { type: number }
  output:
    type: object
    required: [checked, expired]
    properties:
      checked: { type: integer }
      expired: { type: integer }
  handler: { kind: ref, ref: sweepExpiredOrders }
---
apiVersion: cms.mantle.aotter.net/v1
kind: Trigger
metadata:
  name: place-order-http
spec:
  source: { kind: http, method: POST, path: /api/commerce/orders }
  target: { procedure: place-order }
---
# Demo only. Remove before connecting a real provider; see "Where the payment provider plugs in".
apiVersion: cms.mantle.aotter.net/v1
kind: Trigger
metadata:
  name: pay-order-http
spec:
  source: { kind: http, method: POST, path: /api/commerce/orders/pay }
  target: { procedure: pay-order }
---
apiVersion: cms.mantle.aotter.net/v1
kind: Trigger
metadata:
  name: cancel-guest-order-http
spec:
  source: { kind: http, method: POST, path: /api/commerce/orders/cancel }
  target: { procedure: cancel-guest-order }
---
apiVersion: cms.mantle.aotter.net/v1
kind: Trigger
metadata:
  name: adjust-inventory-mcp
spec:
  source: { kind: mcp, surface: staff }
  target: { procedure: adjust-inventory }
---
apiVersion: cms.mantle.aotter.net/v1
kind: Trigger
metadata:
  name: fulfill-order-mcp
spec:
  source: { kind: mcp, surface: staff }
  target: { procedure: fulfill-order }

Points worth noticing:

  • orders, inventory and inventory-movements set root schema.readOnly: true. Admin and Staff MCP keep list and detail access and the declared row Procedures, but suppress and reject generic create, update, status and delete. Only handlers maintain these projections.
  • inventory.productSlug references products, so Inventory stays available under each product. uiSchema.nav.standalone: true also adds a main Admin Nav entry with a product filter for staff who need a cross-product stock list.
  • expire-order and sweep-expired-orders have no Trigger. They are internal Procedures: the Queue consumer and the cron handler invoke them through the generated binding. Nothing external can call them.
  • adjust-inventory.operationId carries x-mcp-hint: idempotency-key; Admin generates a hidden UUID per form, and other callers must reuse theirs on retry. productSlug carries x-mantle-ref: products, so Admin offers "Adjust inventory" on each product row with the slug prefilled. fulfill-order.orderToken does the same on orders rows.
  • picking-list is a raw sql staff View using json_each to unnest order lines. sql Views run on SQLite storage only.

See Reads: Views, REST and MCP and the Schema reference.

Worker and handlers ​

Bindings and Worker entry ​

ts
// src/env.ts
import type { MantleCloudflareEnv } from "@aotter/mantle/cloudflare";
import type { InventoryCoordinator } from "./commerce/InventoryCoordinator.js";

export type ExpiryMessage = { readonly type: "expire-order"; readonly orderToken: string };

export interface Env extends MantleCloudflareEnv {
  readonly INVENTORY_COORDINATOR: DurableObjectNamespace<InventoryCoordinator>;
  readonly ORDER_EXPIRY_QUEUE: Queue<ExpiryMessage>;
  readonly PAYMENT_WEBHOOK_SECRET?: string;
}
toml
# wrangler.toml (additions)
[[durable_objects.bindings]]
name = "INVENTORY_COORDINATOR"
class_name = "InventoryCoordinator"

[[migrations]]
tag = "inventory-v1"
new_sqlite_classes = ["InventoryCoordinator"]

[[queues.producers]]
binding = "ORDER_EXPIRY_QUEUE"
queue = "shop-order-expiry"

[[queues.consumers]]
queue = "shop-order-expiry"
max_concurrency = 1
max_batch_size = 10
max_retries = 5
retry_delay = 30
dead_letter_queue = "shop-order-expiry-dlq"

[triggers]
crons = ["*/5 * * * *"]
ts
// src/index.ts
import { createMantleWorker } from "@aotter/mantle/cloudflare";
import { bindMantle, plan } from "../.mantle/generated/mantle.js";
import { buildCommerceHandlers } from "./commerce/handlers.js";
import { verifyProviderEvent } from "./commerce/provider.js";
import type { Env, ExpiryMessage } from "./env.js";

export { InventoryCoordinator } from "./commerce/InventoryCoordinator.js";

const worker = createMantleWorker<Env>({
  plan,
  extend: ({ getRuntime, env }) => ({
    handlers: buildCommerceHandlers(getRuntime),
    mount({ app }) {
      // Provider callback: raw body + signature, outside the JSON HTTP Trigger path.
      app.post("/payments/callback", async (c) => {
        const raw = await c.req.text();
        const event = await verifyProviderEvent(raw, c.req.header("x-provider-signature"), env.PAYMENT_WEBHOOK_SECRET);
        if (!event) return c.text("invalid signature", 400);
        if (event.type !== "payment.succeeded") return c.text("ignored", 200);
        const api = bindMantle(await getRuntime());
        const result = await api.procedures.payOrder(
          { orderToken: event.orderToken },
          { user: null, staff: null, env, waitUntil: (p) => c.executionCtx.waitUntil(p) },
        );
        if (!result.ok) return c.text(result.diagnostic.code, result.diagnostic.code === "INTERNAL_ERROR" ? 500 : 200);
        return c.text("OK", 200); // paid, already_paid, expired, closed, missing are all terminal for the provider
      });
    },
  }),
});

function internalContext(env: Env, ctx: ExecutionContext) {
  return {
    user: null,
    staff: null,
    env,
    waitUntil: (promise: Promise<unknown>) => ctx.waitUntil(promise),
  } as const;
}

export default {
  fetch: worker.fetch,

  async queue(batch: MessageBatch<ExpiryMessage>, env: Env, ctx: ExecutionContext): Promise<void> {
    let api: ReturnType<typeof bindMantle>;
    try {
      api = bindMantle(await worker.getRuntime(env));
    } catch (error) {
      console.error("[order-expiry] runtime unavailable", error);
      batch.retryAll();
      return;
    }
    for (const message of batch.messages) {
      const body = message.body;
      if (body?.type !== "expire-order" || typeof body.orderToken !== "string") {
        console.error("[order-expiry] discarded malformed message", message.id);
        message.ack();
        continue;
      }
      try {
        const result = await api.procedures.expireOrder({ orderToken: body.orderToken, now: Date.now() }, internalContext(env, ctx));
        if (!result.ok) {
          if (result.diagnostic.code === "INTERNAL_ERROR" || result.diagnostic.code === "CONFLICT") message.retry();
          else message.ack();
        } else if (result.data.outcome === "too_early") {
          message.retry({ delaySeconds: 60 });
        } else {
          message.ack();
        }
      } catch (error) {
        console.error("[order-expiry] transient failure", message.id, error);
        message.retry();
      }
    }
  },

  async scheduled(_controller: ScheduledController, env: Env, ctx: ExecutionContext): Promise<void> {
    const api = bindMantle(await worker.getRuntime(env));
    const result = await api.procedures.sweepExpiredOrders({ now: Date.now() }, internalContext(env, ctx));
    if (!result.ok) throw new Error(`expiry sweep failed: ${result.diagnostic.code}`);
  },
} satisfies ExportedHandler<Env, ExpiryMessage>;

worker.getRuntime(env) returns the same booted runtime fetch uses; bindMantle(runtime).procedures.<lowerCamel>(input, ctx) runs the full Procedure pipeline (auth predicates, input validation, handler, output validation) and returns { ok: true, data } | { ok: false, diagnostic }.

internalContext is a system caller: user: null, staff: null and no auth. It satisfies no requires.auth predicate, so it can only invoke Procedures that declare none. That is intentional. expire-order and sweep-expired-orders have no requires and no Trigger, so the Queue and cron are their only callers. Never hand this context to a staff-guarded Procedure to "skip" authorization; declare an internal Procedure instead.

Inventory authority in a Durable Object ​

One InventoryCoordinator instance per shop (env.INVENTORY_COORDINATOR.getByName("site")) keeps every SKU's counts and every order's reservation in one storage namespace, so a multi-product cart reserves atomically. Every method runs in this.ctx.storage.transaction, checks the current state, and returns a prior outcome when repeated.

ts
// src/commerce/InventoryCoordinator.ts (abridged)
import { DurableObject } from "cloudflare:workers";

export type StockItem = { readonly productSlug: string; readonly quantity: number };
export type StockSnapshot = { readonly productSlug: string; readonly available: number; readonly reserved: number; readonly revision: number };
type OrderState = { readonly items: readonly StockItem[]; readonly expiresAt: number; readonly status: "pending_payment" | "paid" | "fulfilled" | "cancelled" | "expired" };

export class InventoryCoordinator extends DurableObject {
  reserve(orderId: string, items: readonly StockItem[], expiresAt: number) {
    return this.ctx.storage.transaction(async (txn) => {
      const existing = await txn.get<OrderState>(`order:${orderId}`);
      if (existing) return existing.status === "pending_payment" ? { outcome: "already_reserved" as const } : { outcome: "closed" as const };
      // read every SKU; reject if any lacks stock; otherwise available -= q, reserved += q, revision += 1
      // then txn.put(`order:${orderId}`, { items, expiresAt, status: "pending_payment" })
      return { outcome: "reserved" as const, snapshots: [] as StockSnapshot[] };
    });
  }

  pay(orderId: string, now: number) {
    return this.ctx.storage.transaction(async (txn) => {
      const order = await txn.get<OrderState>(`order:${orderId}`);
      if (!order) return { outcome: "missing" as const };
      if (order.status === "paid") return { outcome: "already_paid" as const, items: order.items };
      if (order.status !== "pending_payment") return { outcome: "closed" as const };
      if (order.expiresAt <= now) return release(txn, orderId, order, "expired"); // late payment: release, do not sell
      // reserved -= q for each item; status -> paid
      return { outcome: "paid" as const, items: order.items };
    });
  }

  expire(orderId: string, now: number) { /* pending_payment && expiresAt <= now -> release(...,"expired"); else too_early / closed / missing */ }
  cancel(orderId: string) { /* pending_payment -> release; paid -> available += q; fulfilled|expired -> closed */ }
  fulfill(orderId: string) { /* paid -> fulfilled; repeat -> already_fulfilled */ }

  adjust(operationId: string, productSlug: string, delta: number, reason: string) {
    return this.ctx.storage.transaction(async (txn) => {
      const applied = await txn.get<{ productSlug: string; delta: number; reason: string; snapshot: StockSnapshot }>(`adjustment:${operationId}`);
      if (applied) {
        return applied.productSlug === productSlug && applied.delta === delta && applied.reason === reason
          ? { outcome: "already_adjusted" as const, snapshot: applied.snapshot }
          : { outcome: "idempotency_conflict" as const };
      }
      // available + delta must stay >= 0; write inventory:<slug> and adjustment:<operationId>
      return { outcome: "adjusted" as const, snapshot: {} as StockSnapshot };
    });
  }
}

Storage keys are inventory:<slug>, order:<orderToken> and adjustment:<operationId>. An adjustment key is bound to product, delta and reason: reusing it with different input is idempotency_conflict, which the handler maps to CONFLICT (409), not a second stock change.

The Mantle inventory and inventory-movements rows are query mirrors. Handlers write them only through runtime write use cases (runtime.createDraft, runtime.updateDraft, runtime.deleteEntry, each of which is live on an operational Schema), never through Mantle's tables. The mirror is revision-guarded: a snapshot older than the stored revision is skipped, and a version race on updateDraft is retried. Movement rows use a deterministic movementKey (reserve:<orderToken>:<slug>, sale:<orderToken>:<slug>, adjust:<operationId>) and are inserted only if absent, so replaying any step cannot double-record.

ts
// src/commerce/handlers.ts (abridged)
import type { HandlerContext, MantleRuntime } from "@aotter/mantle/runtime";
import { DiagnosticError, runtimeDiagnostic } from "@aotter/mantle/spec";
import type { MantleHandlers } from "../../.mantle/generated/mantle.js";
import type { Env } from "../env.js";

const CHECKOUT_TTL_MS = 15 * 60 * 1000;
const inventory = (env: Env) => env.INVENTORY_COORDINATOR.getByName("site");

export function buildCommerceHandlers(getRuntime: () => Promise<MantleRuntime>): MantleHandlers<Env> {
  return {
    placeOrder: async (input, ctx) => {
      const runtime = await getRuntime();
      const orderToken = crypto.randomUUID();
      // 1. re-price on the server from published products; reject unknown slugs or mixed currencies
      const priced = await priceItems(runtime, input.items);
      const now = Date.now();
      const expiresAt = now + CHECKOUT_TTL_MS;
      // 2. reserve in the DO first; insufficient stock -> CONFLICT
      const reserved = await inventory(ctx.env).reserve(orderToken, priced.stockItems, expiresAt);
      if (reserved.outcome !== "reserved") throw conflict("/items", reserved, "quantities currently in stock");
      // 3. project into Mantle; on failure compensate in the DO and remove any partial row
      let created: { id: string } | null = null;
      try {
        created = await runtime.createDraft.execute({
          collection: "orders",
          authorId: null,
          ctx,
          data: { orderToken, orderNumber: orderNumber(now, orderToken), orderStatus: "pending_payment", ...priced.orderFields(input), expiresAt },
        });
        await recordStockChange(runtime, reserved.snapshots, priced.stockItems, "reserve", orderToken, ctx);
      } catch (error) {
        await inventory(ctx.env).cancel(orderToken);
        if (created) await runtime.deleteEntry.execute({ id: created.id, collection: "orders", ctx });
        throw error;
      }
      // 4. schedule expiry; the cron sweep covers a lost message
      const enqueue = ctx.env.ORDER_EXPIRY_QUEUE.send({ type: "expire-order", orderToken }, { contentType: "json", delaySeconds: CHECKOUT_TTL_MS / 1000 })
        .catch((error) => console.error(`[commerce] could not enqueue expiry for ${orderToken}`, error));
      if (ctx.waitUntil) ctx.waitUntil(enqueue); else await enqueue;
      return { outcome: "pending_payment", orderToken, orderNumber: orderNumber(now, orderToken), expiresAt, totalMinor: priced.totalMinor, currency: priced.currency };
    },

    payOrder: async ({ orderToken }, ctx) => {
      const runtime = await getRuntime();
      const order = await runtime.entries.readByDataField({ collection: "orders", field: "orderToken", value: orderToken });
      if (!order) return { outcome: "missing", orderToken };
      const result = await inventory(ctx.env).pay(orderToken, Date.now());
      if (result.outcome === "paid" || result.outcome === "already_paid") {
        await recordStockChange(runtime, result.snapshots ?? [], result.items ?? [], "sale", orderToken, ctx);
        await updateOrder(runtime, order, { orderStatus: "paid", paidAt: order.data.paidAt ?? Date.now() }, ctx); // keep the first paidAt
      } else if (result.outcome === "expired") {
        await expirePersistedOrder(runtime, order, result, ctx);
      }
      return { outcome: result.outcome === "paid" || result.outcome === "already_paid" || result.outcome === "expired" ? result.outcome : "closed", orderToken };
    },

    expireOrder: async ({ orderToken, now }, ctx) => {
      const runtime = await getRuntime();
      const result = await inventory(ctx.env).expire(orderToken, now);
      const order = await runtime.entries.readByDataField({ collection: "orders", field: "orderToken", value: orderToken });
      if (result.outcome === "expired" && order) await expirePersistedOrder(runtime, order, result, ctx);
      return { outcome: result.outcome === "expired" || result.outcome === "too_early" || result.outcome === "missing" ? result.outcome : "closed", orderToken };
    },

    sweepExpiredOrders: async ({ now }, ctx) => {
      const runtime = await getRuntime();
      const pending = await runtime.listEntries.execute({ collection: "orders", filter: { field: "orderStatus", value: "pending_payment" }, limit: 100 });
      let expired = 0;
      for (const order of pending) {
        if ((order.data.expiresAt as number) > now) continue;
        const result = await inventory(ctx.env).expire(order.data.orderToken as string, now);
        if (result.outcome === "expired") { await expirePersistedOrder(runtime, order, result, ctx); expired += 1; }
      }
      return { checked: pending.length, expired };
    },

    adjustInventory: async ({ operationId, productSlug, delta, reason }, ctx) => {
      const runtime = await getRuntime();
      const result = await inventory(ctx.env).adjust(operationId, productSlug, delta, reason);
      if (result.outcome === "idempotency_conflict") throw conflict("/operationId", operationId, "an idempotency key used with the same adjustment input");
      if (result.outcome === "insufficient_stock") throw conflict("/delta", delta, "an adjustment that keeps available stock non-negative");
      await persistSnapshots(runtime, [result.snapshot], ctx);
      await ensureMovement(runtime, `adjust:${operationId}`, { productSlug, kind: "adjust", availableDelta: delta, reservedDelta: 0, note: reason }, ctx);
      return result.snapshot;
    },

    fulfillOrder: async ({ orderToken, trackingNumber }, ctx) => { /* DO fulfill -> updateOrder({ orderStatus: "fulfilled", fulfilledAt, trackingNumber }) */ },
    cancelGuestOrder: async ({ orderToken }, ctx) => { /* only pending_payment; DO cancel -> release movements + updateOrder({ orderStatus: "cancelled", cancelledAt, cancelReason }) */ },
  };
}

function conflict(path: string, value: unknown, expected: string): DiagnosticError {
  return new DiagnosticError(runtimeDiagnostic({ code: "CONFLICT", severity: "error", path, value, expected }));
}

expirePersistedOrder records release movements and deletes the pending order row from the mirror; the audit trail keeps the trace. persistSnapshots, ensureMovement, updateOrder and recordStockChange are the revision-guarded and insert-if-absent helpers described above; the retired implementation in Source shows them in full.

Delayed expiry with Queues and a cron sweep ​

place-order sends { type: "expire-order", orderToken } with delaySeconds equal to the checkout TTL. The consumer validates the message before touching the runtime and decides per message:

Consumer observationActionWhy
runtime boot failsbatch.retryAll()nothing was processed
malformed bodyack() and logretrying cannot fix it
Procedure ok: false, code INTERNAL_ERROR or CONFLICTretry()transient or racing with pay/cancel
Procedure ok: false, any other codeack() and logpermanent (for example validation)
outcome: too_earlyretry({ delaySeconds: 60 })delivered before expiresAt
outcome: expired, closed or missingack()terminal
handler threwretry()dispatch failure

Queue delivery is at-least-once and a delayed message can arrive early, late or twice; the DO makes expire idempotent so that is harmless. The */5 * * * * cron runs sweep-expired-orders, which lists pending_payment rows and expires those past expiresAt, so correctness does not depend on any single delivery. Undeliverable messages land in the DLQ after max_retries. This queue is application-owned; Mantle's own deferred-hook queue is a separate opt-in described in Deferred hooks with Queues.

Where the payment provider plugs in ​

The Manifest above ships pay-order-http so the flow can be exercised without a provider. Remove that Trigger in production. Knowing an order token must never count as proof of payment.

Provider callbacks do not fit the JSON HTTP Trigger path: Stripe-style webhooks sign the raw request body and reject re-serialized JSON; ECPay-style callbacks post form data and expect a specific acknowledgement body. Mount the callback as an application route in extend.mount, as src/index.ts above does, on a path outside Mantle's reserved prefixes. In that route:

  1. Read the raw body with c.req.text() and verify the provider signature with the secret from Env. Reject on failure and return before touching Mantle.
  2. Map the verified event to an orderToken (store it as the provider's client reference when creating the provider session).
  3. Invoke the internal pay-order Procedure through bindMantle(await getRuntime()).procedures.payOrder(...). Do not call the handler function directly and do not write Mantle tables from the route; the Procedure pipeline and the DO transition stay the single path.
  4. Treat every callback as a retry. pay returns already_paid on repetition, sale:<orderToken>:<slug> movement keys are inserted only if absent, and paidAt keeps its first value. A duplicate callback therefore cannot deduct inventory twice.
  5. Answer the provider with whatever it requires for acknowledgement once the outcome is terminal (paid, already_paid, expired, closed, missing). Return 5xx only for INTERNAL_ERROR so the provider retries.

Provider return and success URLs are customer navigation only; only the verified server callback confirms payment. Before enabling a real provider, make concurrent pay and cancel callbacks converge: a late paid projection must not overwrite a cancellation that already restored stock. The DO already refuses to pay a non-pending order; keep the Mantle projection ordered by re-reading the row before each updateDraft.

Try it ​

Place an order:

sh
curl -sS -X POST http://localhost:8787/api/commerce/orders \
  -H 'content-type: application/json' \
  -d '{"customerName":"Ada","customerEmail":"ada@example.test","shippingAddress":"1 Shell Lane","items":[{"productSlug":"notebook","quantity":2}]}'
json
{
  "ok": true,
  "data": {
    "outcome": "pending_payment",
    "orderToken": "5b7d1a8e-4c2f-4f7e-9d1a-0b6c2e8f3a11",
    "orderNumber": "MNT-20260910-5B7D1A8E",
    "expiresAt": 1788880263492,
    "totalMinor": 2400,
    "currency": "TWD"
  }
}

Insufficient stock is HTTP 409 CONFLICT at path: "/items"; an unknown slug is HTTP 400 INPUT_VALIDATION_FAILED. With the demo Trigger still present, POST /api/commerce/orders/pay with {"orderToken":"..."} returns { ok: true, data: { outcome: "paid", orderToken } } the first time and already_paid after that.

Public catalog:

sh
curl -sS 'http://localhost:8787/api/views/public-products?show=20'
# {"ok":true,"data":{"rows":[{"id":"...","slug":"notebook","title":"Notebook","priceMinor":1200,"currency":"TWD","updatedAt":...}],"page":1,"show":20,"hasMore":false}}

Staff, on /mcp/staff:

json
{
  "jsonrpc": "2.0", "id": 3, "method": "tools/call",
  "params": {
    "name": "adjust_inventory",
    "arguments": { "operationId": "0d1e2f3a-4b5c-4d6e-8f90-a1b2c3d4e5f6", "productSlug": "notebook", "delta": 50, "reason": "Restock from supplier" }
  }
}

The result is the new snapshot { productSlug, available, reserved, revision }. Repeating the exact call returns the same snapshot; changing delta while reusing operationId is a JSON-RPC error with error.data.code = "CONFLICT". A non-owner staff session is denied with AUTH_DENIED.

SurfaceToolOrigin
/mcpquery_view_public_productspublic View
/mcp/staffquery_view_picking_liststaff sql View
/mcp/staffadjust_inventory, fulfill_orderstaff MCP Triggers
/mcp/staffcreate_draft_products, update_draft_products, request_publish, ...publishing Schema products

orders, inventory and inventory-movements expose no create_record_*/update_record_* tools because they are readOnly. expire_order and sweep_expired_orders are not tools anywhere.

What this deliberately leaves out ​

  • A real provider SDK. verifyProviderEvent is a placeholder for the chosen provider's signature check.
  • Tax, shipping, discounts. totalMinor equals the sum of line totals.
  • Refunds. No Procedure moves a paid order to refunded; cancel-order for staff exists in the retired implementation and returns stock, but it does not move money.
  • Multi-currency carts. All lines must share one currency; mixed carts are rejected.
  • Sharding the Durable Object. One instance per shop is the right default. Split by SKU only after measured single-shop saturation, and expect a distributed reservation workflow when you do.
  • Customer accounts. Orders are guest orders keyed by token; see Procurement approvals for ctx.user-owned rows.

The DO protects local coordination. It is not a distributed transaction across the DO, D1 and the provider; each downstream step must be safe to retry and have a reconciliation path (the sweep, the audit rows, provider retries).

Source ​