diff --git a/client/lib/aethex-collab-service.ts b/client/lib/aethex-collab-service.ts
new file mode 100644
index 00000000..b0a45df9
--- /dev/null
+++ b/client/lib/aethex-collab-service.ts
@@ -0,0 +1,97 @@
+import { supabase } from "@/lib/supabase";
+
+export type TeamVisibility = "public" | "private";
+export type MembershipRole = "owner" | "admin" | "member";
+export type ProjectRole = "owner" | "manager" | "contributor" | "viewer";
+export type TaskStatus = "todo" | "doing" | "done" | "blocked";
+
+export const aethexCollabService = {
+  // Teams
+  async listMyTeams(userId: string) {
+    const { data, error } = await supabase
+      .from("team_memberships")
+      .select("team_id, teams:team_id ( id, name, slug, description, visibility, created_at )")
+      .eq("user_id", userId)
+      .order("created_at", { ascending: false });
+    if (error) return [] as any[];
+    return (data || []) as any[];
+  },
+
+  async createTeam(ownerId: string, name: string, description?: string | null, visibility: TeamVisibility = "private") {
+    const { data, error } = await supabase
+      .from("teams")
+      .insert({ owner_id: ownerId, name, description: description || null, visibility })
+      .select()
+      .single();
+    if (error) throw new Error(error.message || "Unable to create team");
+
+    const team = data as any;
+    await supabase
+      .from("team_memberships")
+      .insert({ team_id: team.id, user_id: ownerId, role: "owner" as const });
+    return team;
+  },
+
+  async addTeamMember(teamId: string, userId: string, role: MembershipRole = "member") {
+    const { error } = await supabase
+      .from("team_memberships")
+      .insert({ team_id: teamId, user_id: userId, role });
+    if (error) throw new Error(error.message || "Unable to add member");
+  },
+
+  // Projects
+  async addProjectMember(projectId: string, userId: string, role: ProjectRole = "contributor") {
+    const { error } = await supabase
+      .from("project_members")
+      .insert({ project_id: projectId, user_id: userId, role });
+    if (error) throw new Error(error.message || "Unable to add project member");
+  },
+
+  async listProjectMembers(projectId: string) {
+    const { data, error } = await supabase
+      .from("project_members")
+      .select("user_id, role, user:user_id ( id, full_name, username, avatar_url )")
+      .eq("project_id", projectId);
+    if (error) return [] as any[];
+    return (data || []) as any[];
+  },
+
+  // Tasks
+  async createTask(projectId: string, title: string, description?: string | null, assigneeId?: string | null, dueDate?: string | null) {
+    const { data, error } = await supabase
+      .from("project_tasks")
+      .insert({ project_id: projectId, title, description: description || null, assignee_id: assigneeId || null, due_date: dueDate || null })
+      .select()
+      .single();
+    if (error) throw new Error(error.message || "Unable to create task");
+    return data as any;
+  },
+
+  async updateTaskStatus(taskId: string, status: TaskStatus) {
+    const { error } = await supabase
+      .from("project_tasks")
+      .update({ status })
+      .eq("id", taskId);
+    if (error) throw new Error(error.message || "Unable to update task");
+  },
+
+  // Activity bus publish
+  async publishActivity(params: {
+    actor_id: string;
+    verb: string;
+    object_type: string;
+    object_id?: string | null;
+    target_user_ids?: string[] | null;
+    target_team_id?: string | null;
+    target_project_id?: string | null;
+    metadata?: any;
+  }) {
+    const resp = await fetch("/api/activity/publish", {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify(params),
+    });
+    if (!resp.ok) throw new Error(await resp.text());
+    return await resp.json();
+  },
+};