@@ -0,0 +1,14 @@
+---
+"@objectstack/spec": minor
+---
+
+feat(spec): a new webhooks service contract declares an optional, transport-neutral redeliver member (`IWebhookService.handleRedeliver`)
+
+Clause-②: yes (widening)
+
+- **What is new.** `@objectstack/spec/contracts` exports a new contract, `IWebhookService`, for the `webhooks` service slot that `@objectstack/plugin-webhooks` fills. It has one optional member, `handleRedeliver?(request: Request): Promise<Response>`. It serves the webhook redeliver door, `POST /api/v1/webhooks/redeliver`, the operator button that sends a finished delivery again.
+- **What it serves.** The same answers as the plugin's self-hosted route. It authenticates the caller from the request's own credentials (`401 UNAUTHENTICATED` when nobody is signed in). It reads `{ "deliveryId": string }` from a JSON body (`400` otherwise). It replays the row through the messaging service, scoped to the caller's active organization (`404 RESOURCE_NOT_FOUND` for a row outside it). It answers `409` with `DELIVERY_NOT_ELIGIBLE` or `DELIVERY_NEVER_SENT` when the outbox refuses the replay, and `200` with the row's id and new status when it succeeds.
+- **Transport-neutral.** A web-standard `Request` goes in and a `Response` comes out: there is no Hono context, no raw app and no `http.server` type. A hosted tenant kernel has no raw app to mount the route on, and the runtime dispatcher's `POST /webhooks/redeliver` domain is the member's one caller.
+- **Why a webhooks slot, not the messaging service's.** The messaging service owns the replay itself. The door (who may press it, whose rows it reaches, what each refusal answers, and the veto over replaying a webhook whose subscription or secret is gone) belongs to the webhook plugin, so the door exists exactly where that plugin is composed.
+- **Absence.** The member is optional, so a webhook service without the door still satisfies the contract. Its caller answers a typed 404 or 501 when the `webhooks` service or this member is absent, never `ROUTE_NOT_FOUND`.
+- **Nothing changes for existing code.** No existing contract or member moved. Nothing registers the `webhooks` slot or calls the member yet: the plugin implementation and the dispatcher domain land separately, and the plugin's self-hosted route stays as it is.
@@ -163,6 +163,7 @@
     "ISmsTransport (interface)",
     "IStorageService (interface)",
     "ITeamGraphService (interface)",
+    "IWebhookService (interface)",
     "ImportObjectOpts (interface)",
     "ImportObjectResult (interface)",
     "InboxListResult (interface)",
 
@@ -163,6 +163,7 @@
     "ISmsTransport": "src/contracts/sms-service.ts#ISmsTransport (interface)",
     "IStorageService": "src/contracts/storage-service.ts#IStorageService (interface)",
     "ITeamGraphService": "src/contracts/sharing-service.ts#ITeamGraphService (interface)",
+    "IWebhookService": "src/contracts/webhook-service.ts#IWebhookService (interface)",
     "ImportObjectOpts": "src/contracts/external-datasource-service.ts#ImportObjectOpts (interface)",
     "ImportObjectResult": "src/contracts/external-datasource-service.ts#ImportObjectResult (interface)",
     "InboxListResult": "src/contracts/notification-service.ts#InboxListResult (interface)",
 
@@ -60,6 +60,7 @@ export * from './share-link-service.js';
 // Reports are `report` metadata (`ReportSchema`); an ad-hoc object query is a
 // ListView.
 export * from './approval-service.js';
+export * from './webhook-service.js';
 export * from './package-service.js';
 export * from './knowledge-service.js';
 export * from './knowledge-adapter.js';
 
@@ -0,0 +1,50 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+//
+// [#22754] `IWebhookService.handleRedeliver`: the webhook redeliver door,
+// declared on the `webhooks` slot's contract transport-neutrally (the first
+// segment of the #22564 bridge for `POST /api/v1/webhooks/redeliver`).
+//
+// The card asks for a type-level pin, and these aliases are it: the contract
+// carries the member, OPTIONAL, at the web-standard
+// `(request: Request) => Promise<Response>` shape (no Hono context, no raw app,
+// no `http.server` type, no execution context beside the request), and the
+// `contracts` barrel exports the same contract the next segments import. The
+// value-level pin below is the optionality's other half: a service object
+// without the member still satisfies `IWebhookService`.
+//
+// The optionality pin is a type alias, not `expectTypeOf`: `toEqualTypeOf`
+// cannot tell an optional member from a REQUIRED one typed `T | undefined`,
+// while `{} extends Pick<…>` can. The aliases are exported so TS6196 does not
+// flag them as unused; `check:test-typecheck` compiles this file.
+
+import { describe, it, expect } from 'vitest';
+import type { IWebhookService } from './webhook-service';
+import type { IWebhookService as IWebhookServiceFromBarrel } from './index';
+
+type Eq<A, B> = (<T>() => T extends A ? 1 : 2) extends (<T>() => T extends B ? 1 : 2) ? true : false;
+type Assert<T extends true> = T;
+
+type HandleRedeliver = NonNullable<IWebhookService['handleRedeliver']>;
+
+/** Optional: a service may omit it. A required member turns this alias red. */
+export type RedeliverIsOptional = Assert<{} extends Pick<IWebhookService, 'handleRedeliver'> ? true : false>;
+
+/** One web-standard `Request` in: the whole input, with no execution context beside it. */
+export type RedeliverTakesOneRequest = Assert<Eq<Parameters<HandleRedeliver>, [request: Request]>>;
+
+/** A web-standard `Response` out, asynchronously. */
+export type RedeliverAnswersAResponse = Assert<Eq<ReturnType<HandleRedeliver>, Promise<Response>>>;
+
+/** The barrel (`@objectstack/spec/contracts`) exports this contract, not a look-alike. */
+export type BarrelExportsTheContract = Assert<Eq<IWebhookServiceFromBarrel, IWebhookService>>;
+
+describe('IWebhookService.handleRedeliver: the webhook redeliver door, declared transport-neutrally', () => {
+    it('is optional: a service object without it still satisfies IWebhookService', () => {
+        // The population the optionality is for: a webhook service with no
+        // redeliver door, which the caller must answer with a typed refusal
+        // rather than call.
+        const service: IWebhookService = {};
+
+        expect(service.handleRedeliver).toBeUndefined();
+    });
+});
@@ -0,0 +1,97 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * @objectstack/spec/contracts/webhook-service
+ *
+ * Cross-package contract for the outbound-webhook plugin's service slot. The
+ * implementation lives in `@objectstack/plugin-webhooks` and is registered as
+ * the `webhooks` service. The slot is named after the plugin's platform
+ * capability token (`webhooks`), as the `approvals` slot is named after
+ * plugin-approvals'.
+ *
+ * Webhook DELIVERY is not on this contract. A delivery is a row on the
+ * messaging service's shared outbound-HTTP outbox (ADR-0018 M3), and
+ * `@objectstack/service-messaging` owns sending it, retrying it and replaying
+ * it. This slot carries what the webhook plugin owns on top of that outbox:
+ * today, one door.
+ *
+ * [#22754] Why the redeliver door lives on this slot and not on the messaging
+ * service's: the bridged behaviour is the door, and the door is this plugin's.
+ * The plugin decides who may press it (any signed-in user), whose rows it
+ * reaches (the caller's active organization), and what each refusal answers.
+ * It is also what installs the messaging service's veto over replaying a
+ * webhook row whose subscription or signing secret is gone, before it
+ * enqueues its first row. So the door exists exactly where this plugin is
+ * composed. A door on the messaging slot would also exist on a kernel without
+ * this plugin, where that veto is never installed, and the dispatcher would
+ * hold a second copy of the door's rules.
+ */
+
+/**
+ * The webhook plugin's service: the occupant of the `webhooks` slot.
+ *
+ * Every member is optional. A kernel without `@objectstack/plugin-webhooks`
+ * leaves the slot empty, and a caller probes for the member it needs before
+ * calling it.
+ */
+export interface IWebhookService {
+  /**
+   * **The webhook redeliver door, served transport-neutrally.** It is
+   * `POST /api/v1/webhooks/redeliver`, the operator button that sends a
+   * finished delivery again (#22564; declared here as the first segment of
+   * the bridge that the maintainer's ruling A on #22438 directs for this
+   * endpoint).
+   *
+   * What it serves, exactly as the plugin's self-hosted mount serves it today:
+   *  - It authenticates the caller from the request's own credentials, through
+   *    the kernel's `auth` service. Any signed-in user may press it; with no
+   *    signed-in user it answers `401 UNAUTHENTICATED`.
+   *  - It reads a JSON body `{ "deliveryId": string }`. A body that is not
+   *    JSON answers `400 INVALID_REQUEST`, and a `deliveryId` that is
+   *    missing, not a string or blank answers `400 MISSING_REQUIRED_FIELD`.
+   *  - It replays the row through the messaging service's redelivery, scoped
+   *    to the caller's active organization (#10740). A row outside that
+   *    organization is not found: `404 RESOURCE_NOT_FOUND`. ⛔ The tenant is
+   *    never dropped and never bypassed.
+   *  - A row the outbox refuses to replay answers `409` with the refusal's own
+   *    code: `DELIVERY_NOT_ELIGIBLE` (the row is not finished, or the
+   *    producer's veto refused it) or `DELIVERY_NEVER_SENT` (the row is a
+   *    parked record that was never sent, so replaying it would send it
+   *    unsigned).
+   *  - Any other failure answers `500 INTERNAL_ERROR`.
+   *  - A replayed row answers `200` with `{ success: true, data: { id, status } }`:
+   *    the row's id and its new status. Every refusal is JSON in the
+   *    `{ success: false, error: { code, message } }` envelope.
+   *
+   * **Transport-neutral, deliberately.** A web-standard `Request` goes in and
+   * a `Response` comes out. There is no Hono context, no raw app and no
+   * `http.server` type. A hosted tenant kernel owns no socket, so it has no
+   * raw app to mount the route on. The dispatcher reaches that kernel
+   * instead, and this signature is the one a dispatcher can call.
+   *
+   * **It takes no `ExecutionContext`.** It resolves the caller from the
+   * request, which is the rule the self-hosted mount applies, so both kernel
+   * shapes judge the same caller by one rule, in one place.
+   *
+   * **Its one caller** is the runtime `HttpDispatcher`'s exact
+   * `POST /webhooks/redeliver` domain (the next segment of #22564). That
+   * domain forwards the request with its body unread and returns this
+   * member's `Response` as it is. The path is not on the ADR-0069 auth-gate
+   * allow-list, so on that shape a signed-in caller whose session still owes
+   * an authentication step is stopped before this member runs: the
+   * dispatcher door is stricter than the self-hosted mount, never looser. The
+   * plugin's self-hosted raw-app mount is not a caller, and the path is never
+   * mounted twice.
+   *
+   * **Optional, and its absence is loud.** A webhook service without the door
+   * still satisfies this contract, so the caller probes for presence. An
+   * empty `webhooks` slot or an absent member answers a typed 404 or 501,
+   * ⛔ never `ROUTE_NOT_FOUND`: that answer would tell an operator the URL is
+   * wrong, when what is missing is the service behind it.
+   *
+   * @param request - The forwarded `POST`: the caller's credentials are in
+   *   its headers, and the `deliveryId` is in its JSON body
+   * @returns The JSON answer for the operator
+   */
+  handleRedeliver?(request: Request): Promise<Response>;
+}