feat(client): expose paseo.projects.subscribe() through the public SDK (#3983)

* feat(client): expose project update subscriptions

* docs(sdk): clarify project subscription initialization

* docs(sdk): document race-free project initialization

---------

Co-authored-by: paseo-bot[bot] <266920839+paseo-bot[bot]@users.noreply.github.com>

packages/client/src/index.test.ts

@@ -335,6 +335,63 @@ test("project actions list registered projects through the existing RPC", async
   await client.close();
 });
 
+test("project actions subscribe to existing project updates", async () => {
+  const { client, ws } = await connectClient();
+  const updates: string[] = [];
+  const unsubscribe = client.projects.subscribe((update) => {
+    updates.push(update.kind === "upsert" ? update.project.projectDisplayName : update.projectId);
+  });
+
+  ws.message(
+    sessionMessage({
+      type: "project.update",
+      payload: {
+        kind: "upsert",
+        project: {
+          projectId: "project_sdk",
+          projectKey: "sdk",
+          projectDisplayName: "Renamed SDK",
+          projectCustomName: "Renamed SDK",
+          projectCustomIconRevision: null,
+          projectIconRevision: "icon-revision",
+          projectRootPath: "/repo/sdk",
+          projectKind: "git",
+          syncSeq: 9,
+        },
+        generation: "daemon-generation",
+        seq: 9,
+      },
+    }),
+  );
+  ws.message(
+    sessionMessage({
+      type: "project.update",
+      payload: {
+        kind: "remove",
+        projectId: "project_removed",
+        generation: "daemon-generation",
+        seq: 10,
+      },
+    }),
+  );
+
+  expect(updates).toEqual(["Renamed SDK", "project_removed"]);
+
+  unsubscribe();
+  ws.message(
+    sessionMessage({
+      type: "project.update",
+      payload: {
+        kind: "remove",
+        projectId: "project_after_unsubscribe",
+      },
+    }),
+  );
+  expect(updates).toEqual(["Renamed SDK", "project_removed"]);
+
+  await client.close();
+});
+
 test("agent actions list the daemon directory without exposing the low-level client", async () => {
   const { client, ws } = await connectClient();
   const listedAgent = createAgent({ title: "Planner" });

packages/client/src/index.ts

@@ -104,6 +104,11 @@ export type PaseoProjectListOptions = Omit<ProjectListRequestMessage, "type" | "
   requestId?: string;
 };
 export type PaseoProjectListResult = ProjectListResponseMessage["payload"];
+export type PaseoProjectUpdate = Extract<
+  SessionOutboundMessage,
+  { type: "project.update" }
+>["payload"];
+export type PaseoProjectUpdateHandler = (update: PaseoProjectUpdate) => void;
 
 export interface PaseoAgentListResult {
   requestId: string;
@@ -173,6 +178,7 @@ export interface PaseoWorkspaceHandle {
 
 export interface PaseoProjectActions {
   list(options?: PaseoProjectListOptions): Promise<PaseoProjectListResult>;
+  subscribe(handler: PaseoProjectUpdateHandler): () => void;
 }
 
 export interface PaseoWorkspaceActions {
@@ -494,6 +500,10 @@ export function createPaseoApi(daemonClient: DaemonClient): PaseoApi {
     terminals,
     projects: {
       list: (options) => daemonClient.listProjects(options),
+      subscribe: (handler) =>
+        daemonClient.on("project.update", (message) => {
+          handler(message.payload);
+        }),
     },
     workspaces: {
       list: (options) => daemonClient.fetchWorkspaces(options),

public-docs/sdk/reference.md

@@ -112,9 +112,12 @@ Creation options include `config`, `cwd`, `parent`, `title`, `prompt`, `env`, `o
 
 ## `client.projects`
 
-| Method           | Result                   | Behavior                                                                      |
-| ---------------- | ------------------------ | ----------------------------------------------------------------------------- |
-| `list(options?)` | `PaseoProjectListResult` | Lists every registered project, including projects with no active workspaces. |
+| Method               | Result                   | Behavior                                                                                |
+| -------------------- | ------------------------ | --------------------------------------------------------------------------------------- |
+| `list(options?)`     | `PaseoProjectListResult` | Lists every registered project, including projects with no active workspaces.           |
+| `subscribe(handler)` | Unsubscribe function     | Listens only for future project upserts/removals. Pair with `list()` for initial state. |
+
+To build a complete project cache without an initialization gap, subscribe and buffer updates before awaiting `list()`. Initialize the cache from the list result, then apply buffered updates in arrival order.
 
 ## `client.workspaces`