Take the word call out of the member API

membership$ is typed as RTCMembership, the subset of the js-sdk CallMembership that hosts read. UnknownCallError is UnknownRTCError throughout, not only in the export. applicationData reaches the membership whole, since the js-sdk takes it next to the intent. The plan records the three slices as implemented.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

sdk/MemberMediaPlan.md

@@ -383,8 +383,7 @@ No behaviour change; one PR of renames and type narrowing.
 
 ## Changed behaviour
 
-What a host sees differently, per slice. The first block is implemented; the
-rest follows the slices above and is marked as planned.
+What a host sees differently, per slice. All four blocks are implemented.
 
 ### `tracks$` and `isActive$` (this plan, implemented)
 
@@ -416,19 +415,20 @@ Differences in what the values mean:
   before had an order.
 - The harness labels audio elements with `data-active`. Test ids are unchanged.
 
-### Slice 1, local track controls (planned)
+### Slice 1, local track controls
 
 - `switchCamera()` on the local media becomes `switchFacingMode()` on the local
-  camera track; it rejects, instead of resolving `undefined`, when there is no
-  camera track.
+  camera track, so there is always a track to call it on; it still resolves
+  `undefined` where the facing mode is unknown.
 - Input device and processor changes are calls on the track. The SDK no longer
   reacts to `audioInputDeviceId$`, `videoInputDeviceId$` or `videoProcessor$`;
   a host that changed a setting and expected the SDK to follow now calls
-  `setDevice` or `setProcessor` itself.
+  `setDevice` or `setProcessor` itself. The initial device and processor travel
+  with the publish request instead.
 - `setEnabled(false)` on a local track mutes it and keeps the publication, as
   `setMicrophoneEnabled(false)` does today.
 
-### Slice 2, `publish` and `unpublish` (planned)
+### Slice 2, `publish` and `unpublish`
 
 - Screen sharing is `publish({ source: "screenShare" })` and `unpublish(id)`.
   A capture failure rejects the promise; there is no `screenShareError$` to
@@ -444,12 +444,13 @@ false, cameraEnabled: false` before.
 - Capture settings travel with each request. A host that set
   `capture.screenShare` once sets it on each screen share publish instead.
 
-### Slice 3, names (planned)
+### Slice 3, names
 
 - `membership$` is typed as `RTCMembership`. A host that reached for a
   `CallMembership` member outside the narrowed set must import the js-sdk type
   itself; the object is unchanged.
-- `UnknownCallError` is renamed; `index.ts` stops exporting it as
-  `UnknownRTCError`. Error codes do not change.
-- `applicationData` is forwarded whole once the js-sdk takes it. Until then the
-  behaviour is as today: only `m.call.intent` reaches the membership.
+- `UnknownCallError` is `UnknownRTCError` in the SDK too, not only in the
+  export. Error codes do not change. The two `Livekit*` errors are left to
+  slice 11 of `SdkMigration.md`, which renames them on both sides at once.
+- `applicationData` is forwarded whole: the js-sdk takes it next to
+  `m.call.intent`, which the membership format carries as a field of its own.

sdk/SdkArchitecture.md

@@ -115,7 +115,7 @@ without anyone hearing it. `leave()` pauses the upstream again and sends the lea
 | ----------------- | ------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------ |
 | client            | a `MatrixRTCClient`: one room, one slot, one local member                                                                                   | `MatrixClient` is always written out |
 | session           | the MatrixRTC session in the room: the set of memberships. Only used for the js-sdk object, which stays inside the SDK as `JsSdkRTCSession` | MSC4143                              |
-| membership        | one device's MatrixRTC state event, the js-sdk `CallMembership`. The js-sdk name is kept until it renames it                                |                                      |
+| membership        | one device's MatrixRTC state event, seen by hosts as `RTCMembership`, the js-sdk `CallMembership` behind it                                 |                                      |
 | member            | an `RTCMember`: a membership plus what the SDK derives from it (display name, transport, media)                                             | Element Call's "matrixLivekitMember" |
 | participant       | a LiveKit participant, the media side of a member. Never leaves the SDK                                                                     |                                      |
 | transport         | where media is exchanged: a LiveKit service url today, described by `TransportMetadata`                                                     | MSC4143 "focus"                      |
@@ -334,7 +334,23 @@ export interface DataMessage {
 ### Members
 
 ```ts
-import { type CallMembership } from "matrix-js-sdk/lib/matrixrtc";
+/**
+ * What a membership says, as hosts read it. The js-sdk `CallMembership` is
+ * behind it; anything beyond this is the js-sdk's API, not the SDK's.
+ */
+export type RTCMembership = Pick<
+  CallMembership,
+  | "userId"
+  | "deviceId"
+  | "memberId"
+  | "rtcBackendIdentity"
+  | "application"
+  | "applicationData"
+  | "getTransport"
+  | "transports"
+  | "createdTs"
+  | "getAbsoluteExpiry"
+>;
 
 export interface RTCMember {
   local: boolean;
@@ -346,7 +362,7 @@ export interface RTCMember {
   id: string;
   userId: string;
   deviceId: string;
-  membership$: Behavior<CallMembership>;
+  membership$: Behavior<RTCMembership>;
   /**
    * Matrix room state rather than MatrixRTC, but the SDK already holds the
    * room and every consumer wants them next to the membership. Disambiguated
@@ -658,9 +674,8 @@ public API only.
 
 - **Publishing before `join()`.** The initial requests are published at the
   join; creating the tracks earlier, for a lobby preview, is still missing.
-- **`applicationData` after the join.** The option is read once. The client
-  still updates `m.call.intent` from the camera state, as Element Call did; that
-  moves to the host once the data can be updated.
+- **`applicationData` after the join.** The option is read once; there is no
+  way to update it on a live membership yet.
 - **Raw local state.** The local member's state machine (`LocalMemberState`) stays
   internal; `status$`, `disconnectReason$` and `fatalError$` are its public view.
   A developer panel may want it as `LocalRTCMember.state$`.

sdk/index.ts

@@ -49,7 +49,7 @@ export {
   NoMatrix2AuthorizationService,
   PeerConnectionTimeoutError,
   SFURoomCreationRestrictedError,
-  UnknownCallError as UnknownRTCError,
+  UnknownRTCError,
 } from "./src/errors";
 
 export * from "./src/api";

sdk/src/api.ts

@@ -48,9 +48,10 @@ export interface MatrixRTCClientOptions {
   /** The application's slot in the room. Default `ROOM`. */
   slot?: string;
   /**
-   * Whatever the application wants to say about itself in the membership.
-   * Opaque to the SDK. Today the js-sdk carries one key, `m.call.intent`
-   * (`"audio"` or `"video"`); anything else is dropped until it can.
+   * Whatever the application wants to say about itself in the membership,
+   * under namespaced keys. Opaque to the SDK, apart from `m.call.intent`
+   * (`"audio"` or `"video"`), which the membership format carries as a
+   * field of its own.
    */
   applicationData?: Record<string, unknown>;
   /** Session timings the host has configured; the defaults otherwise. */
@@ -211,13 +212,31 @@ export type ResolvedTransport =
 // ---------------------------------------------------------------------------
 // Members
 
+/**
+ * What a membership says, as hosts read it. The js-sdk `CallMembership` is
+ * behind it; anything beyond this is the js-sdk's API, not the SDK's.
+ */
+export type RTCMembership = Pick<
+  CallMembership,
+  | "userId"
+  | "deviceId"
+  | "memberId"
+  | "rtcBackendIdentity"
+  | "application"
+  | "applicationData"
+  | "getTransport"
+  | "transports"
+  | "createdTs"
+  | "getAbsoluteExpiry"
+>;
+
 export interface RTCMember {
   local: boolean;
   /** The identity the media backend knows this member by. */
   id: string;
   userId: string;
   deviceId: string;
-  membership$: Behavior<CallMembership>;
+  membership$: Behavior<RTCMembership>;
   displayName$: Behavior<string>;
   avatarUrl$: Behavior<string | undefined>;
   /** Which transport this member is on; undefined when the membership has none. */

sdk/src/errors.ts

@@ -80,7 +80,7 @@ export class MembershipManagerError extends MatrixRTCError {
   }
 }
 
-export class UnknownCallError extends MatrixRTCError {
+export class UnknownRTCError extends MatrixRTCError {
   public constructor(cause: Error) {
     super(
       cause.message || "Unknown error",

sdk/src/session/Connection.ts

@@ -40,7 +40,7 @@ import {
   LivekitConnectionError,
   PeerConnectionTimeoutError,
   SFURoomCreationRestrictedError,
-  UnknownCallError,
+  UnknownRTCError,
 } from "../errors";
 
 export interface ConnectionOpts {
@@ -381,8 +381,8 @@ export class Connection {
         error instanceof MatrixRTCError
           ? error
           : error instanceof Error
-            ? new UnknownCallError(error)
-            : new UnknownCallError(new Error(`${error}`)),
+            ? new UnknownRTCError(error)
+            : new UnknownRTCError(new Error(`${error}`)),
       );
       // Its okay to ignore the throw. The error is part of the state.
       throw error;

sdk/src/session/joinJsSdkSession.ts

@@ -47,8 +47,8 @@ export function joinJsSdkSession(
     delayedLeave,
   }: Options,
 ): void {
-  // The one piece of application data the js-sdk can put in a membership
-  const intent = applicationData?.["m.call.intent"];
+  // The membership format carries the intent as a field of its own
+  const { "m.call.intent": intent, ...rest } = applicationData ?? {};
   const callIntent =
     typeof intent === "string" ? (intent as RTCCallIntent) : undefined;
   // Give up on the network as soon as either the sync has been down for the
@@ -61,6 +61,7 @@ export function joinJsSdkSession(
   session.joinRTCSession(ownMembershipIdentity, [transport], {
     notificationType: sendNotificationType,
     callIntent,
+    applicationData: rest,
     manageMediaKeys: encryptMedia,
     delayedLeaveEventRestartMs: delayedLeave.restart_ms,
     delayedLeaveEventDelayMs: delayedLeave.delay_ms,