fix: narrower codegen types at caller/provider level

api-specs/openrpc-dapp-api.json

@@ -175,6 +175,7 @@
                 "title": "KernelInfo",
                 "type": "object",
                 "description": "Represents a Wallet Gateway.",
+                "additionalProperties": false,
                 "properties": {
                     "id": {
                         "title": "id",
@@ -202,6 +203,7 @@
                 "title": "LedgerApiResult",
                 "type": "object",
                 "description": "Ledger Api configuration options",
+                "additionalProperties": false,
                 "properties": {
                     "response": {
                         "title": "response",
@@ -220,6 +222,7 @@
                 "title": "JsPrepareSubmissionRequest",
                 "type": "object",
                 "description": "Structure representing the request for prepare and execute calls",
+                "additionalProperties": false,
                 "properties": {
                     "commandId": {
                         "$ref": "api-specs/openrpc-dapp-api.json#/components/schemas/CommandId"
@@ -274,6 +277,7 @@
                 "title": "DisclosedContract",
                 "type": "object",
                 "description": "Structure representing a disclosed contract for transaction execution",
+                "additionalProperties": false,
                 "properties": {
                     "templateId": {
                         "title": "templateId",
@@ -503,6 +507,7 @@
             "StatusEvent": {
                 "title": "StatusEvent",
                 "type": "object",
+                "additionalProperties": false,
                 "properties": {
                     "kernel": {
                         "$ref": "api-specs/openrpc-dapp-api.json#/components/schemas/KernelInfo"
@@ -525,6 +530,7 @@
                     "network": {
                         "title": "network",
                         "type": "object",
+                        "additionalProperties": false,
                         "description": "Network information, if connected to a network.",
                         "properties": {
                             "networkId": {
@@ -536,6 +542,7 @@
                                 "title": "LedgerApiConfig",
                                 "type": "object",
                                 "description": "Ledger API configuration.",
+                                "additionalProperties": false,
                                 "properties": {
                                     "baseUrl": {
                                         "title": "baseUrl",
@@ -553,6 +560,7 @@
                         "title": "session",
                         "type": "object",
                         "description": "Session information, if authenticated.",
+                        "additionalProperties": false,
                         "properties": {
                             "accessToken": {
                                 "title": "accessToken",

core/rpc-generator/src/components/client.ts

@@ -21,6 +21,21 @@ import { RpcTransport } from '@canton-network/core-rpc-transport'
 
 <%= methodTypings.toString("typescript").replace(/export type AnyOf[A-Za-z0-9]+ =(?:[\\r\\n]|.)*?;/gm, "") %>
 
+type AsyncReturnType<T> = T extends (...args: any[]) => Promise<infer R>
+    ? R
+    : never
+
+export type RpcMethods = {
+  <% openrpcDocument.methods.forEach((method) => { %>
+    <%= method.name %>: {
+        params: Parameters<<%= _.upperFirst(method.name) %>>
+        result: AsyncReturnType<<%= _.upperFirst(method.name) %>>
+    }
+  <% }); %>
+}
+
+export type RpcClientRequest<M extends keyof RpcMethods> = (method: M, params?: RpcMethods[M]['params']) => Promise<RpcMethods[M]['result']>
+
 export class <%= className %> {
   public transport: RpcTransport;
 
@@ -33,15 +48,21 @@ export class <%= className %> {
    * <%= method.summary %>
    */
   // tslint:disable-next-line:max-line-length
-  public async request(method: "<%= method.name %>", ...params: Parameters<<%= _.upperFirst(method.name) %>>): ReturnType<<%= _.upperFirst(method.name) %>>
+  // public async request(method: "<%= method.name %>", ...params: Parameters<<%= _.upperFirst(method.name) %>>): ReturnType<<%= _.upperFirst(method.name) %>>
   <% }); %>
-  public async request(method: string, params?: RequestPayload['params']): Promise<unknown> {
-    const response = await this.transport.submit({ method, params });
+
+  public async request<M extends keyof RpcMethods>(method: M, params?: RpcMethods[M]['params'][0]): Promise<RpcMethods[M]['result']> {
+    const submitParams = params ? { method, params } : { method }
+
+    const response = await this.transport.submit({
+        method,
+        params: submitParams,
+    })
 
     if ('error' in response) {
         throw new Error('RPC error: ' + response.error.code + ' - ' + response.error.message);
     } else {
-        return response.result;
+        return response.result as RpcMethods[M]['result'];
     }
   }
 }

core/splice-provider/src/SpliceProvider.ts

@@ -1,12 +1,17 @@
 // Copyright (c) 2025-2026 Digital Asset (Switzerland) GmbH and/or its affiliates. All rights reserved.
 // SPDX-License-Identifier: Apache-2.0
 
-import { RequestPayload } from '@canton-network/core-types'
+import SpliceWalletJSONRPCDAppAPI, {
+    RpcMethods,
+} from '@canton-network/core-wallet-dapp-rpc-client'
 
 export type EventListener<T> = (...args: T[]) => void
 
 export interface SpliceProvider {
-    request<T>(args: RequestPayload): Promise<T>
+    request<M extends keyof RpcMethods>(
+        method: M,
+        params?: RpcMethods[M]['params'][0]
+    ): Promise<RpcMethods[M]['result']>
     on<T>(event: string, listener: EventListener<T>): SpliceProvider
     emit<T>(event: string, ...args: T[]): boolean
     removeListener<T>(
@@ -17,12 +22,19 @@ export interface SpliceProvider {
 
 export abstract class SpliceProviderBase implements SpliceProvider {
     listeners: { [event: string]: EventListener<unknown>[] }
+    _client: SpliceWalletJSONRPCDAppAPI
 
-    constructor() {
+    constructor(client: SpliceWalletJSONRPCDAppAPI) {
         this.listeners = {} // Event listeners
+        this._client = client
     }
 
-    abstract request<T>(args: RequestPayload): Promise<T>
+    public async request(
+        method: keyof RpcMethods,
+        params?: RpcMethods[typeof method]['params'][0]
+    ): Promise<RpcMethods[typeof method]['result']> {
+        return this._client.request(method, params)
+    }
 
     // Event handling
     public on<T>(event: string, listener: EventListener<T>): SpliceProvider {

core/splice-provider/src/SpliceProviderHttp.ts

@@ -1,11 +1,7 @@
 // Copyright (c) 2025-2026 Digital Asset (Switzerland) GmbH and/or its affiliates. All rights reserved.
 // SPDX-License-Identifier: Apache-2.0
 
-import {
-    isSpliceMessageEvent,
-    RequestPayload,
-    WalletEvent,
-} from '@canton-network/core-types'
+import { isSpliceMessageEvent, WalletEvent } from '@canton-network/core-types'
 import { HttpTransport } from '@canton-network/core-rpc-transport'
 import SpliceWalletJSONRPCDAppAPI from '@canton-network/core-wallet-dapp-rpc-client'
 import { SpliceProviderBase } from './SpliceProvider'
@@ -23,7 +19,6 @@ let connection: GatewaySocket = null
 
 export class SpliceProviderHttp extends SpliceProviderBase {
     private sessionToken?: string
-    private client: SpliceWalletJSONRPCDAppAPI
 
     private createClient(sessionToken?: string): SpliceWalletJSONRPCDAppAPI {
         const transport = new HttpTransport(this.url, sessionToken)
@@ -61,18 +56,17 @@ export class SpliceProviderHttp extends SpliceProviderBase {
     }
 
     constructor(
+        client: SpliceWalletJSONRPCDAppAPI,
         private url: URL,
         sessionToken?: string
     ) {
-        super()
+        super(client)
 
         if (sessionToken) {
             this.sessionToken = sessionToken
             this.openSocket(url, sessionToken)
         }
 
-        this.client = this.createClient(sessionToken)
-
         // Listen for the auth success event sent from the WK UI popup to the SDK running in the parent window.
         window.addEventListener('message', async (event) => {
             if (!isSpliceMessageEvent(event)) return
@@ -81,13 +75,13 @@ export class SpliceProviderHttp extends SpliceProviderBase {
                 event.data.type === WalletEvent.SPLICE_WALLET_IDP_AUTH_SUCCESS
             ) {
                 this.sessionToken = event.data.token
-                this.client = this.createClient(this.sessionToken)
+                this._client = this.createClient(this.sessionToken)
                 this.openSocket(this.url, event.data.token)
 
                 // We requery the status explicitly here, as it's not guaranteed that the socket will be open & authenticated
                 // before the `onConnected` event is fired from the `addSession` RPC call. The dappApi.StatusResult and
                 // dappApi.OnConnectedEvent are mapped manually to avoid dependency.
-                this.request({ method: 'status' })
+                this.request('status')
                     .then((status) => {
                         this.emit('onConnected', status)
                     })
@@ -100,13 +94,4 @@ export class SpliceProviderHttp extends SpliceProviderBase {
             }
         })
     }
-
-    public async request<T>({ method, params }: RequestPayload): Promise<T> {
-        return (await (
-            this.client.request as (
-                method: string,
-                params?: RequestPayload['params']
-            ) => Promise<unknown>
-        )(method, params)) as T
-    }
 }

core/splice-provider/src/SpliceProviderWindow.ts

@@ -1,26 +1,15 @@
 // Copyright (c) 2025-2026 Digital Asset (Switzerland) GmbH and/or its affiliates. All rights reserved.
 // SPDX-License-Identifier: Apache-2.0
 
-import { RequestPayload } from '@canton-network/core-types'
-import { WindowTransport } from '@canton-network/core-rpc-transport'
+// import { RequestPayload } from '@canton-network/core-types'
+// import { WindowTransport } from '@canton-network/core-rpc-transport'
 import SpliceWalletJSONRPCDAppAPI from '@canton-network/core-wallet-dapp-rpc-client'
 import { SpliceProviderBase } from './SpliceProvider.js'
 
 export class SpliceProviderWindow extends SpliceProviderBase {
-    private client: SpliceWalletJSONRPCDAppAPI
+    // private client: SpliceWalletJSONRPCDAppAPI
 
-    constructor() {
-        super()
-        const transport = new WindowTransport(window)
-        this.client = new SpliceWalletJSONRPCDAppAPI(transport)
-    }
-
-    public async request<T>({ method, params }: RequestPayload): Promise<T> {
-        return (await (
-            this.client.request as (
-                method: string,
-                params?: RequestPayload['params']
-            ) => Promise<unknown>
-        )(method, params)) as T
+    constructor(client: SpliceWalletJSONRPCDAppAPI) {
+        super(client)
     }
 }

core/types/src/index.ts

@@ -19,9 +19,7 @@ export type PartyId = z.infer<typeof PartyId>
  */
 export const RequestPayload = z.object({
     method: z.string(),
-    params: z.optional(
-        z.union([z.array(z.unknown()), z.record(z.string(), z.unknown())])
-    ),
+    params: z.optional(z.union([z.array(z.unknown()), z.looseObject({})])),
 })
 export type RequestPayload = z.infer<typeof RequestPayload>