3 files changed, 60 insertions, 0 deletions

diff --git a/src/adapters/ws/index.ts b/src/adapters/ws/index.ts
index 1309db0..3a6a97d 100644
--- a/src/adapters/ws/index.ts
+++ b/src/adapters/ws/index.ts
@@ -4,6 +4,7 @@ import type {
   ConversationCompactedMessage,
   ConversationOpenMessage,
   ConversationStatusChangedMessage,
+  ExtensionsChangedMessage,
   WsClientMessage,
 } from "@dispatch/transport-contract";
 import type { SurfaceServerMessage } from "@dispatch/ui-contract";
@@ -27,6 +28,12 @@ export interface SurfaceSocketOptions {
   onConversationStatusChanged?: (msg: ConversationStatusChangedMessage) => void;
   /** Broadcast when a conversation's history has been compacted (reload needed). */
   onConversationCompacted?: (msg: ConversationCompactedMessage) => void;
+  /**
+   * Broadcast after every plugin-manager mutation (plan 05 §11): every
+   * connected frontend refetches its extension list (the server re-pushes the
+   * workspace-filtered surface catalog itself).
+   */
+  onExtensionsChanged?: (msg: ExtensionsChangedMessage) => void;
   onReopen?: () => void;
   socketFactory?: (url: string) => WebSocketLike;
 }
@@ -75,6 +82,8 @@ export function createSurfaceSocket(opts: SurfaceSocketOptions): SurfaceSocketHa
           opts.onConversationStatusChanged?.(msg as ConversationStatusChangedMessage);
         } else if (msg.type === "conversation.compacted") {
           opts.onConversationCompacted?.(msg as ConversationCompactedMessage);
+        } else if (msg.type === "extensions-changed") {
+          opts.onExtensionsChanged?.(msg as ExtensionsChangedMessage);
         } else {
           opts.onMessage(msg as SurfaceServerMessage);
         }
diff --git a/src/adapters/ws/logic.test.ts b/src/adapters/ws/logic.test.ts
index 43cf8ff..c4ec7e3 100644
--- a/src/adapters/ws/logic.test.ts
+++ b/src/adapters/ws/logic.test.ts
@@ -1,6 +1,13 @@
 import { describe, expect, it } from "vitest";
 import { nextBackoffMs, parseServerMessage, serialize } from "./logic";
 
+describe("serialize — workspace.set (plan 06 §6.4)", () => {
+  it("serializes a workspace.set client message", () => {
+    const msg = { type: "workspace.set" as const, workspaceId: "ws-1" };
+    expect(JSON.parse(serialize(msg))).toEqual(msg);
+  });
+});
+
 describe("serialize", () => {
   it("serializes a subscribe message", () => {
     const msg = { type: "subscribe" as const, surfaceId: "s1" };
@@ -430,3 +437,29 @@ describe("nextBackoffMs", () => {
     }
   });
 });
+
+describe("parseServerMessage — extensions-changed (plan 05)", () => {
+  it("parses the broadcast with a pluginId", () => {
+    const result = parseServerMessage(
+      JSON.stringify({ type: "extensions-changed", action: "unload", pluginId: "mcp" }),
+    );
+    expect(result).toEqual({ type: "extensions-changed", action: "unload", pluginId: "mcp" });
+  });
+
+  it("parses a scan broadcast (no pluginId)", () => {
+    const result = parseServerMessage(
+      JSON.stringify({ type: "extensions-changed", action: "scan" }),
+    );
+    expect(result).toEqual({ type: "extensions-changed", action: "scan" });
+  });
+
+  it("rejects an unknown action", () => {
+    expect(
+      parseServerMessage(JSON.stringify({ type: "extensions-changed", action: "explode" })),
+    ).toBeNull();
+  });
+
+  it("rejects a missing action", () => {
+    expect(parseServerMessage(JSON.stringify({ type: "extensions-changed" }))).toBeNull();
+  });
+});
diff --git a/src/adapters/ws/logic.ts b/src/adapters/ws/logic.ts
index 72a6338..696655b 100644
--- a/src/adapters/ws/logic.ts
+++ b/src/adapters/ws/logic.ts
@@ -4,6 +4,7 @@ import type {
   ConversationCompactedMessage,
   ConversationOpenMessage,
   ConversationStatusChangedMessage,
+  ExtensionsChangedMessage,
   WsClientMessage,
   WsServerMessage,
 } from "@dispatch/transport-contract";
@@ -24,6 +25,7 @@ const VALID_SERVER_TYPES = new Set([
   "conversation.open",
   "conversation.statusChanged",
   "conversation.compacted",
+  "extensions-changed",
 ]);
 
 /** Serialize a client message to a JSON string for the wire. */
@@ -162,6 +164,22 @@ export function parseServerMessage(data: string): WsServerMessage | null {
       };
       return msg;
     }
+    case "extensions-changed": {
+      // Plugin-manager broadcast (plan 05): the payload is intentionally
+      // minimal — clients refetch GET /plugins + the (server re-pushed)
+      // surface catalog rather than diffing here.
+      const action = parsed.action;
+      if (action !== "load" && action !== "unload" && action !== "reload") {
+        if (action !== "scan" && action !== "forget") return null;
+      }
+      const pluginId = parsed.pluginId;
+      const msg: ExtensionsChangedMessage = {
+        type: "extensions-changed",
+        action,
+        ...(pluginId !== undefined && typeof pluginId === "string" ? { pluginId } : {}),
+      };
+      return msg;
+    }
     default:
       return null;
   }