From bc89952f10edb28009f679640bcf8aca71fa3dab Mon Sep 17 00:00:00 2001
From: Jason Woltje <jason@diversecanvas.com>
Date: Sat, 28 Feb 2026 21:26:24 -0600
Subject: [PATCH] feat(web): add user edit/invite dialogs and workspace member
 management (MS21-UI-002, MS21-UI-004)

---
 .../settings/users/page.test.tsx              | 160 +++++
 .../(authenticated)/settings/users/page.tsx   | 456 ++++++++-----
 .../settings/workspaces/page.test.tsx         | 140 ++--
 .../settings/workspaces/page.tsx              | 597 +++++++++++++++---
 apps/web/src/lib/api/admin.ts                 |   1 +
 5 files changed, 1046 insertions(+), 308 deletions(-)
 create mode 100644 apps/web/src/app/(authenticated)/settings/users/page.test.tsx

diff --git a/apps/web/src/app/(authenticated)/settings/users/page.test.tsx b/apps/web/src/app/(authenticated)/settings/users/page.test.tsx
new file mode 100644
index 0000000..e65167e
--- /dev/null
+++ b/apps/web/src/app/(authenticated)/settings/users/page.test.tsx
@@ -0,0 +1,160 @@
+import type { ReactElement, ReactNode } from "react";
+
+import { WorkspaceMemberRole } from "@mosaic/shared";
+import { render, screen, waitFor } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+import {
+  deactivateUser,
+  fetchAdminUsers,
+  inviteUser,
+  updateUser,
+  type AdminUsersResponse,
+} from "@/lib/api/admin";
+import { fetchUserWorkspaces, updateWorkspaceMemberRole } from "@/lib/api/workspaces";
+import UsersSettingsPage from "./page";
+
+vi.mock("next/link", () => ({
+  default: function LinkMock({
+    children,
+    href,
+  }: {
+    children: ReactNode;
+    href: string;
+  }): ReactElement {
+    return <a href={href}>{children}</a>;
+  },
+}));
+
+vi.mock("@/lib/api/admin", () => ({
+  fetchAdminUsers: vi.fn(),
+  inviteUser: vi.fn(),
+  updateUser: vi.fn(),
+  deactivateUser: vi.fn(),
+}));
+
+vi.mock("@/lib/api/workspaces", () => ({
+  fetchUserWorkspaces: vi.fn(),
+  updateWorkspaceMemberRole: vi.fn(),
+}));
+
+const fetchAdminUsersMock = vi.mocked(fetchAdminUsers);
+const inviteUserMock = vi.mocked(inviteUser);
+const updateUserMock = vi.mocked(updateUser);
+const deactivateUserMock = vi.mocked(deactivateUser);
+const fetchUserWorkspacesMock = vi.mocked(fetchUserWorkspaces);
+const updateWorkspaceMemberRoleMock = vi.mocked(updateWorkspaceMemberRole);
+
+const adminUsersResponse: AdminUsersResponse = {
+  data: [
+    {
+      id: "user-1",
+      name: "Alice",
+      email: "alice@example.com",
+      emailVerified: true,
+      image: null,
+      createdAt: "2026-01-01T00:00:00.000Z",
+      deactivatedAt: null,
+      isLocalAuth: false,
+      invitedAt: null,
+      invitedBy: null,
+      workspaceMemberships: [
+        {
+          workspaceId: "workspace-1",
+          workspaceName: "Personal Workspace",
+          role: WorkspaceMemberRole.ADMIN,
+          joinedAt: "2026-01-01T00:00:00.000Z",
+        },
+      ],
+    },
+  ],
+  meta: {
+    total: 1,
+    page: 1,
+    limit: 50,
+    totalPages: 1,
+  },
+};
+
+describe("UsersSettingsPage", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+
+    fetchAdminUsersMock.mockResolvedValue(adminUsersResponse);
+    fetchUserWorkspacesMock.mockResolvedValue([
+      {
+        id: "workspace-1",
+        name: "Personal Workspace",
+        ownerId: "owner-1",
+        role: WorkspaceMemberRole.OWNER,
+        createdAt: "2026-01-01T00:00:00.000Z",
+      },
+    ]);
+    inviteUserMock.mockResolvedValue({
+      userId: "user-2",
+      invitationToken: "token-1",
+      email: "new@example.com",
+      invitedAt: "2026-01-02T00:00:00.000Z",
+    });
+    const firstUser = adminUsersResponse.data[0];
+    if (!firstUser) {
+      throw new Error("Expected at least one admin user in test fixtures");
+    }
+
+    updateUserMock.mockResolvedValue(firstUser);
+    deactivateUserMock.mockResolvedValue(firstUser);
+    updateWorkspaceMemberRoleMock.mockResolvedValue({
+      workspaceId: "workspace-1",
+      userId: "user-1",
+      role: WorkspaceMemberRole.ADMIN,
+      joinedAt: "2026-01-01T00:00:00.000Z",
+      user: {
+        id: "user-1",
+        email: "alice@example.com",
+        name: "Alice",
+        image: null,
+      },
+    });
+  });
+
+  it("invites a user with email and role from the dialog", async () => {
+    const user = userEvent.setup();
+    render(<UsersSettingsPage />);
+
+    expect(await screen.findByText("User Directory")).toBeInTheDocument();
+
+    await user.click(screen.getByRole("button", { name: "Invite User" }));
+    await user.type(screen.getByLabelText("Email"), "new@example.com");
+    await user.click(screen.getByRole("button", { name: "Send Invite" }));
+
+    await waitFor(() => {
+      expect(inviteUserMock).toHaveBeenCalledWith({
+        email: "new@example.com",
+        role: WorkspaceMemberRole.MEMBER,
+        workspaceId: "workspace-1",
+      });
+    });
+  });
+
+  it("opens user detail dialog from row click and saves edited profile fields", async () => {
+    const user = userEvent.setup();
+    render(<UsersSettingsPage />);
+
+    expect(await screen.findByText("alice@example.com")).toBeInTheDocument();
+
+    await user.click(screen.getByText("Alice"));
+
+    const nameInput = await screen.findByLabelText("Name");
+    await user.clear(nameInput);
+    await user.type(nameInput, "Alice Updated");
+
+    await user.click(screen.getByRole("button", { name: "Save Changes" }));
+
+    await waitFor(() => {
+      expect(updateUserMock).toHaveBeenCalledWith("user-1", { name: "Alice Updated" });
+    });
+
+    expect(updateWorkspaceMemberRoleMock).not.toHaveBeenCalled();
+  });
+});
diff --git a/apps/web/src/app/(authenticated)/settings/users/page.tsx b/apps/web/src/app/(authenticated)/settings/users/page.tsx
index e177bf4..bc3bde8 100644
--- a/apps/web/src/app/(authenticated)/settings/users/page.tsx
+++ b/apps/web/src/app/(authenticated)/settings/users/page.tsx
@@ -5,12 +5,14 @@ import {
   useEffect,
   useState,
   type ChangeEvent,
+  type KeyboardEvent,
   type ReactElement,
   type SyntheticEvent,
 } from "react";
 import Link from "next/link";
-import { Pencil, UserPlus, UserX } from "lucide-react";
+import { UserPlus, UserX } from "lucide-react";
 import { WorkspaceMemberRole } from "@mosaic/shared";
+import { isValidEmail } from "@/components/workspace/validation";
 import { Badge } from "@/components/ui/badge";
 import { Button } from "@/components/ui/button";
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
@@ -42,7 +44,6 @@ import {
   AlertDialogHeader,
   AlertDialogTitle,
 } from "@/components/ui/alert-dialog";
-import { fetchUserWorkspaces } from "@/lib/api/workspaces";
 import {
   deactivateUser,
   fetchAdminUsers,
@@ -50,9 +51,11 @@ import {
   updateUser,
   type AdminUser,
   type AdminUsersResponse,
+  type AdminWorkspaceMembership,
   type InviteUserDto,
   type UpdateUserDto,
 } from "@/lib/api/admin";
+import { fetchUserWorkspaces, updateWorkspaceMemberRole } from "@/lib/api/workspaces";
 
 const ROLE_PRIORITY: Record<WorkspaceMemberRole, number> = {
   [WorkspaceMemberRole.OWNER]: 4,
@@ -63,27 +66,40 @@ const ROLE_PRIORITY: Record<WorkspaceMemberRole, number> = {
 
 const INITIAL_INVITE_FORM = {
   email: "",
-  name: "",
-  workspaceId: "",
   role: WorkspaceMemberRole.MEMBER,
 };
 
+const INITIAL_DETAIL_FORM = {
+  name: "",
+  email: "",
+  role: WorkspaceMemberRole.MEMBER,
+  workspaceId: null as string | null,
+  workspaceName: null as string | null,
+};
+
+interface DetailInitialState {
+  name: string;
+  email: string;
+  role: WorkspaceMemberRole;
+  workspaceId: string | null;
+}
+
 function toRoleLabel(role: WorkspaceMemberRole): string {
   return `${role.charAt(0)}${role.slice(1).toLowerCase()}`;
 }
 
-function getPrimaryRole(user: AdminUser): WorkspaceMemberRole | null {
+function getPrimaryMembership(user: AdminUser): AdminWorkspaceMembership | null {
   const [firstMembership, ...restMemberships] = user.workspaceMemberships;
   if (!firstMembership) {
     return null;
   }
 
   return restMemberships.reduce((highest, membership) => {
-    if (ROLE_PRIORITY[membership.role] > ROLE_PRIORITY[highest]) {
-      return membership.role;
+    if (ROLE_PRIORITY[membership.role] > ROLE_PRIORITY[highest.role]) {
+      return membership;
     }
     return highest;
-  }, firstMembership.role);
+  }, firstMembership);
 }
 
 export default function UsersSettingsPage(): ReactElement {
@@ -93,21 +109,23 @@ export default function UsersSettingsPage(): ReactElement {
   const [isRefreshing, setIsRefreshing] = useState<boolean>(false);
   const [error, setError] = useState<string | null>(null);
 
+  const [defaultWorkspaceId, setDefaultWorkspaceId] = useState<string | null>(null);
+  const [isAdmin, setIsAdmin] = useState<boolean | null>(null);
+
   const [isInviteOpen, setIsInviteOpen] = useState<boolean>(false);
   const [inviteForm, setInviteForm] = useState(INITIAL_INVITE_FORM);
   const [inviteError, setInviteError] = useState<string | null>(null);
   const [isInviting, setIsInviting] = useState<boolean>(false);
 
+  const [detailTarget, setDetailTarget] = useState<AdminUser | null>(null);
+  const [detailForm, setDetailForm] = useState(INITIAL_DETAIL_FORM);
+  const [detailInitial, setDetailInitial] = useState<DetailInitialState | null>(null);
+  const [detailError, setDetailError] = useState<string | null>(null);
+  const [isSavingDetails, setIsSavingDetails] = useState<boolean>(false);
+
   const [deactivateTarget, setDeactivateTarget] = useState<AdminUser | null>(null);
   const [isDeactivating, setIsDeactivating] = useState<boolean>(false);
 
-  const [editTarget, setEditTarget] = useState<AdminUser | null>(null);
-  const [editName, setEditName] = useState<string>("");
-  const [editError, setEditError] = useState<string | null>(null);
-  const [isEditing, setIsEditing] = useState<boolean>(false);
-
-  const [isAdmin, setIsAdmin] = useState<boolean | null>(null);
-
   const loadUsers = useCallback(async (showLoadingState: boolean): Promise<void> => {
     try {
       if (showLoadingState) {
@@ -139,9 +157,12 @@ export default function UsersSettingsPage(): ReactElement {
           WorkspaceMemberRole.OWNER,
           WorkspaceMemberRole.ADMIN,
         ];
-        setIsAdmin(workspaces.some((ws) => adminRoles.includes(ws.role)));
+
+        setDefaultWorkspaceId(workspaces[0]?.id ?? null);
+        setIsAdmin(workspaces.some((workspace) => adminRoles.includes(workspace.role)));
       })
       .catch(() => {
+        setDefaultWorkspaceId(null);
         setIsAdmin(true); // fail open
       });
   }, []);
@@ -151,15 +172,44 @@ export default function UsersSettingsPage(): ReactElement {
     setInviteError(null);
   }
 
-  function handleInviteOpenChange(open: boolean): void {
-    if (!open && !isInviting) {
-      resetInviteForm();
-    }
-    setIsInviteOpen(open);
+  function openUserDetails(user: AdminUser): void {
+    const primaryMembership = getPrimaryMembership(user);
+
+    const nextDetailForm = {
+      name: user.name,
+      email: user.email,
+      role: primaryMembership?.role ?? WorkspaceMemberRole.MEMBER,
+      workspaceId: primaryMembership?.workspaceId ?? null,
+      workspaceName: primaryMembership?.workspaceName ?? null,
+    };
+
+    setDetailTarget(user);
+    setDetailForm(nextDetailForm);
+    setDetailInitial({
+      name: nextDetailForm.name,
+      email: nextDetailForm.email,
+      role: nextDetailForm.role,
+      workspaceId: nextDetailForm.workspaceId,
+    });
+    setDetailError(null);
   }
 
-  async function handleInviteSubmit(e: SyntheticEvent): Promise<void> {
-    e.preventDefault();
+  function resetUserDetails(): void {
+    setDetailTarget(null);
+    setDetailForm(INITIAL_DETAIL_FORM);
+    setDetailInitial(null);
+    setDetailError(null);
+  }
+
+  function handleUserRowKeyDown(event: KeyboardEvent<HTMLDivElement>, user: AdminUser): void {
+    if (event.key === "Enter" || event.key === " ") {
+      event.preventDefault();
+      openUserDetails(user);
+    }
+  }
+
+  async function handleInviteSubmit(event: SyntheticEvent): Promise<void> {
+    event.preventDefault();
     setInviteError(null);
 
     const email = inviteForm.email.trim();
@@ -168,17 +218,18 @@ export default function UsersSettingsPage(): ReactElement {
       return;
     }
 
-    const dto: InviteUserDto = { email };
-
-    const name = inviteForm.name.trim();
-    if (name) {
-      dto.name = name;
+    if (!isValidEmail(email)) {
+      setInviteError("Please enter a valid email address.");
+      return;
     }
 
-    const workspaceId = inviteForm.workspaceId.trim();
-    if (workspaceId) {
-      dto.workspaceId = workspaceId;
-      dto.role = inviteForm.role;
+    const dto: InviteUserDto = {
+      email,
+      role: inviteForm.role,
+    };
+
+    if (defaultWorkspaceId) {
+      dto.workspaceId = defaultWorkspaceId;
     }
 
     try {
@@ -194,6 +245,75 @@ export default function UsersSettingsPage(): ReactElement {
     }
   }
 
+  async function handleDetailSubmit(event: SyntheticEvent): Promise<void> {
+    event.preventDefault();
+
+    if (detailTarget === null || detailInitial === null) {
+      return;
+    }
+
+    const name = detailForm.name.trim();
+    const email = detailForm.email.trim();
+
+    if (!name) {
+      setDetailError("Name is required.");
+      return;
+    }
+
+    if (!email) {
+      setDetailError("Email is required.");
+      return;
+    }
+
+    if (!isValidEmail(email)) {
+      setDetailError("Please enter a valid email address.");
+      return;
+    }
+
+    const didUpdateUser = name !== detailInitial.name || email !== detailInitial.email;
+    const didUpdateRole =
+      detailForm.workspaceId !== null &&
+      detailForm.workspaceId === detailInitial.workspaceId &&
+      detailForm.role !== detailInitial.role;
+
+    if (!didUpdateUser && !didUpdateRole) {
+      resetUserDetails();
+      return;
+    }
+
+    try {
+      setIsSavingDetails(true);
+      setDetailError(null);
+
+      if (didUpdateUser) {
+        const dto: UpdateUserDto = {};
+
+        if (name !== detailInitial.name) {
+          dto.name = name;
+        }
+
+        if (email !== detailInitial.email) {
+          dto.email = email;
+        }
+
+        await updateUser(detailTarget.id, dto);
+      }
+
+      if (didUpdateRole && detailForm.workspaceId !== null) {
+        await updateWorkspaceMemberRole(detailForm.workspaceId, detailTarget.id, {
+          role: detailForm.role,
+        });
+      }
+
+      resetUserDetails();
+      await loadUsers(false);
+    } catch (err: unknown) {
+      setDetailError(err instanceof Error ? err.message : "Failed to update user");
+    } finally {
+      setIsSavingDetails(false);
+    }
+  }
+
   async function confirmDeactivate(): Promise<void> {
     if (!deactivateTarget) {
       return;
@@ -212,23 +332,6 @@ export default function UsersSettingsPage(): ReactElement {
     }
   }
 
-  async function handleEditSubmit(): Promise<void> {
-    if (editTarget === null) return;
-    setIsEditing(true);
-    setEditError(null);
-    try {
-      const dto: UpdateUserDto = {};
-      if (editName.trim()) dto.name = editName.trim();
-      await updateUser(editTarget.id, dto);
-      setEditTarget(null);
-      await loadUsers(false);
-    } catch (err: unknown) {
-      setEditError(err instanceof Error ? err.message : "Failed to update user");
-    } finally {
-      setIsEditing(false);
-    }
-  }
-
   if (isAdmin === false) {
     return (
       <div className="p-8 max-w-2xl">
@@ -262,7 +365,15 @@ export default function UsersSettingsPage(): ReactElement {
             {isRefreshing ? "Refreshing..." : "Refresh"}
           </Button>
 
-          <Dialog open={isInviteOpen} onOpenChange={handleInviteOpenChange}>
+          <Dialog
+            open={isInviteOpen}
+            onOpenChange={(open) => {
+              if (!open && !isInviting) {
+                resetInviteForm();
+              }
+              setIsInviteOpen(open);
+            }}
+          >
             <DialogTrigger asChild>
               <Button>
                 <UserPlus className="h-4 w-4 mr-2" />
@@ -273,13 +384,13 @@ export default function UsersSettingsPage(): ReactElement {
               <DialogHeader>
                 <DialogTitle>Invite User</DialogTitle>
                 <DialogDescription>
-                  Create an invited account and optionally assign workspace access.
+                  Invite a new user and assign their role for your default workspace.
                 </DialogDescription>
               </DialogHeader>
 
               <form
-                onSubmit={(e) => {
-                  void handleInviteSubmit(e);
+                onSubmit={(event) => {
+                  void handleInviteSubmit(event);
                 }}
                 className="space-y-4"
               >
@@ -289,8 +400,8 @@ export default function UsersSettingsPage(): ReactElement {
                     id="invite-email"
                     type="email"
                     value={inviteForm.email}
-                    onChange={(e: ChangeEvent<HTMLInputElement>) => {
-                      setInviteForm((prev) => ({ ...prev, email: e.target.value }));
+                    onChange={(event: ChangeEvent<HTMLInputElement>) => {
+                      setInviteForm((prev) => ({ ...prev, email: event.target.value }));
                     }}
                     placeholder="user@example.com"
                     maxLength={255}
@@ -298,33 +409,6 @@ export default function UsersSettingsPage(): ReactElement {
                   />
                 </div>
 
-                <div className="space-y-2">
-                  <Label htmlFor="invite-name">Name (optional)</Label>
-                  <Input
-                    id="invite-name"
-                    type="text"
-                    value={inviteForm.name}
-                    onChange={(e: ChangeEvent<HTMLInputElement>) => {
-                      setInviteForm((prev) => ({ ...prev, name: e.target.value }));
-                    }}
-                    placeholder="Jane Doe"
-                    maxLength={255}
-                  />
-                </div>
-
-                <div className="space-y-2">
-                  <Label htmlFor="invite-workspace-id">Workspace ID (optional)</Label>
-                  <Input
-                    id="invite-workspace-id"
-                    type="text"
-                    value={inviteForm.workspaceId}
-                    onChange={(e: ChangeEvent<HTMLInputElement>) => {
-                      setInviteForm((prev) => ({ ...prev, workspaceId: e.target.value }));
-                    }}
-                    placeholder="UUID workspace id"
-                  />
-                </div>
-
                 <div className="space-y-2">
                   <Label htmlFor="invite-role">Role</Label>
                   <Select
@@ -344,9 +428,13 @@ export default function UsersSettingsPage(): ReactElement {
                       ))}
                     </SelectContent>
                   </Select>
-                  <p className="text-xs text-muted-foreground">
-                    Role is only applied when workspace ID is provided.
-                  </p>
+                  {defaultWorkspaceId ? (
+                    <p className="text-xs text-muted-foreground">Role will be applied on invite.</p>
+                  ) : (
+                    <p className="text-xs text-muted-foreground">
+                      No default workspace found. User will be invited without workspace assignment.
+                    </p>
+                  )}
                 </div>
 
                 {inviteError ? (
@@ -360,7 +448,10 @@ export default function UsersSettingsPage(): ReactElement {
                     type="button"
                     variant="outline"
                     onClick={() => {
-                      handleInviteOpenChange(false);
+                      if (!isInviting) {
+                        setIsInviteOpen(false);
+                        resetInviteForm();
+                      }
                     }}
                     disabled={isInviting}
                   >
@@ -409,17 +500,25 @@ export default function UsersSettingsPage(): ReactElement {
         <Card>
           <CardHeader>
             <CardTitle>User Directory</CardTitle>
-            <CardDescription>Name, email, role, and account status.</CardDescription>
+            <CardDescription>Click a user to view details or edit profile fields.</CardDescription>
           </CardHeader>
           <CardContent className="space-y-3">
             {users.map((user) => {
-              const primaryRole = getPrimaryRole(user);
+              const primaryMembership = getPrimaryMembership(user);
               const isActive = user.deactivatedAt === null;
 
               return (
                 <div
                   key={user.id}
-                  className="rounded-md border p-4 flex flex-col gap-3 md:flex-row md:items-center md:justify-between"
+                  className="rounded-md border p-4 flex flex-col gap-3 md:flex-row md:items-center md:justify-between cursor-pointer hover:bg-muted/30"
+                  role="button"
+                  tabIndex={0}
+                  onClick={() => {
+                    openUserDetails(user);
+                  }}
+                  onKeyDown={(event) => {
+                    handleUserRowKeyDown(event, user);
+                  }}
                 >
                   <div className="space-y-1 min-w-0">
                     <p className="font-semibold truncate">{user.name || "Unnamed User"}</p>
@@ -428,28 +527,17 @@ export default function UsersSettingsPage(): ReactElement {
 
                   <div className="flex items-center gap-2 flex-wrap md:justify-end">
                     <Badge variant="outline">
-                      {primaryRole ? toRoleLabel(primaryRole) : "No role"}
+                      {primaryMembership ? toRoleLabel(primaryMembership.role) : "No role"}
                     </Badge>
                     <Badge variant={isActive ? "secondary" : "destructive"}>
                       {isActive ? "Active" : "Inactive"}
                     </Badge>
-                    <Button
-                      variant="outline"
-                      size="sm"
-                      onClick={() => {
-                        setEditTarget(user);
-                        setEditName(user.name);
-                        setEditError(null);
-                      }}
-                    >
-                      <Pencil className="h-4 w-4 mr-2" />
-                      Edit Role
-                    </Button>
                     {isActive ? (
                       <Button
                         variant="destructive"
                         size="sm"
-                        onClick={() => {
+                        onClick={(event) => {
+                          event.stopPropagation();
                           setDeactivateTarget(user);
                         }}
                       >
@@ -465,6 +553,117 @@ export default function UsersSettingsPage(): ReactElement {
         </Card>
       )}
 
+      <Dialog
+        open={detailTarget !== null}
+        onOpenChange={(open) => {
+          if (!open && !isSavingDetails) {
+            resetUserDetails();
+          }
+        }}
+      >
+        <DialogContent>
+          <DialogHeader>
+            <DialogTitle>User Details</DialogTitle>
+            <DialogDescription>
+              Edit profile details for {detailTarget?.email ?? "selected user"}.
+            </DialogDescription>
+          </DialogHeader>
+
+          <form
+            onSubmit={(event) => {
+              void handleDetailSubmit(event);
+            }}
+            className="space-y-4"
+          >
+            <div className="space-y-2">
+              <Label htmlFor="detail-name">Name</Label>
+              <Input
+                id="detail-name"
+                value={detailForm.name}
+                onChange={(event: ChangeEvent<HTMLInputElement>) => {
+                  setDetailForm((prev) => ({ ...prev, name: event.target.value }));
+                }}
+                placeholder="Full name"
+                maxLength={255}
+                disabled={isSavingDetails}
+                required
+              />
+            </div>
+
+            <div className="space-y-2">
+              <Label htmlFor="detail-email">Email</Label>
+              <Input
+                id="detail-email"
+                type="email"
+                value={detailForm.email}
+                onChange={(event: ChangeEvent<HTMLInputElement>) => {
+                  setDetailForm((prev) => ({ ...prev, email: event.target.value }));
+                }}
+                placeholder="user@example.com"
+                maxLength={255}
+                disabled={isSavingDetails}
+                required
+              />
+            </div>
+
+            <div className="space-y-2">
+              <Label htmlFor="detail-role">Role</Label>
+              <Select
+                value={detailForm.role}
+                disabled={detailForm.workspaceId === null || isSavingDetails}
+                onValueChange={(value) => {
+                  setDetailForm((prev) => ({ ...prev, role: value as WorkspaceMemberRole }));
+                }}
+              >
+                <SelectTrigger id="detail-role">
+                  <SelectValue placeholder="Select role" />
+                </SelectTrigger>
+                <SelectContent>
+                  {Object.values(WorkspaceMemberRole).map((role) => (
+                    <SelectItem key={role} value={role}>
+                      {toRoleLabel(role)}
+                    </SelectItem>
+                  ))}
+                </SelectContent>
+              </Select>
+              {detailForm.workspaceName ? (
+                <p className="text-xs text-muted-foreground">
+                  Role updates apply to: {detailForm.workspaceName}
+                </p>
+              ) : (
+                <p className="text-xs text-muted-foreground">
+                  This user has no workspace membership. Role cannot be updated.
+                </p>
+              )}
+            </div>
+
+            {detailError !== null ? (
+              <p className="text-sm text-destructive" role="alert">
+                {detailError}
+              </p>
+            ) : null}
+
+            <DialogFooter>
+              <Button
+                type="button"
+                variant="outline"
+                onClick={() => {
+                  if (!isSavingDetails) {
+                    resetUserDetails();
+                  }
+                }}
+                disabled={isSavingDetails}
+              >
+                Cancel
+              </Button>
+              <Button type="submit" disabled={isSavingDetails}>
+                {isSavingDetails ? "Saving..." : "Save Changes"}
+              </Button>
+            </DialogFooter>
+          </form>
+        </DialogContent>
+      </Dialog>
+
       <AlertDialog
         open={deactivateTarget !== null}
         onOpenChange={(open) => {
@@ -496,55 +695,4 @@ export default function UsersSettingsPage(): ReactElement {
       </AlertDialog>
     </div>
   );
-
-  <Dialog
-    open={editTarget !== null}
-    onOpenChange={(open) => {
-      if (!open && !isEditing) {
-        setEditTarget(null);
-        setEditError(null);
-      }
-    }}
-  >
-    <DialogContent>
-      <DialogHeader>
-        <DialogTitle>Edit User Role</DialogTitle>
-        <DialogDescription>Change role for {editTarget?.email ?? "user"}.</DialogDescription>
-      </DialogHeader>
-      <div className="space-y-4 py-2">
-        {editError !== null ? <p className="text-sm text-destructive">{editError}</p> : null}
-        <div className="space-y-2">
-          <Label htmlFor="edit-name">Display Name</Label>
-          <Input
-            id="edit-name"
-            value={editName}
-            onChange={(e: ChangeEvent<HTMLInputElement>) => {
-              setEditName(e.target.value);
-            }}
-            placeholder="Full name"
-            disabled={isEditing}
-          />
-        </div>
-      </div>
-      <DialogFooter>
-        <Button
-          variant="outline"
-          onClick={() => {
-            setEditTarget(null);
-          }}
-          disabled={isEditing}
-        >
-          Cancel
-        </Button>
-        <Button
-          onClick={() => {
-            void handleEditSubmit();
-          }}
-          disabled={isEditing}
-        >
-          {isEditing ? "Saving..." : "Save"}
-        </Button>
-      </DialogFooter>
-    </DialogContent>
-  </Dialog>;
 }
diff --git a/apps/web/src/app/(authenticated)/settings/workspaces/page.test.tsx b/apps/web/src/app/(authenticated)/settings/workspaces/page.test.tsx
index c8310f1..cf1f2cd 100644
--- a/apps/web/src/app/(authenticated)/settings/workspaces/page.test.tsx
+++ b/apps/web/src/app/(authenticated)/settings/workspaces/page.test.tsx
@@ -1,12 +1,12 @@
-import type { UserWorkspace } from "@/lib/api/workspaces";
+import type { UserWorkspace, WorkspaceMemberEntry } from "@/lib/api/workspaces";
 import type { ReactElement, ReactNode } from "react";
 
 import { WorkspaceMemberRole } from "@mosaic/shared";
 import { render, screen, waitFor } from "@testing-library/react";
 import userEvent from "@testing-library/user-event";
 import { beforeEach, describe, expect, it, vi } from "vitest";
-import { createWorkspace, fetchUserWorkspaces } from "@/lib/api/workspaces";
 
+import { createWorkspace, fetchUserWorkspaces, fetchWorkspaceMembers } from "@/lib/api/workspaces";
 import WorkspacesPage from "./page";
 
 vi.mock("next/link", () => ({
@@ -21,33 +21,23 @@ vi.mock("next/link", () => ({
   },
 }));
 
-vi.mock("@/components/workspace/WorkspaceCard", () => ({
-  WorkspaceCard: function WorkspaceCardMock({
-    workspace,
-    userRole,
-    memberCount,
-  }: {
-    workspace: { name: string };
-    userRole: WorkspaceMemberRole;
-    memberCount: number;
-  }): ReactElement {
-    return (
-      <div data-testid="workspace-card">
-        {workspace.name} | {userRole} | {String(memberCount)}
-      </div>
-    );
-  },
-}));
-
 vi.mock("@/lib/api/workspaces", () => ({
   fetchUserWorkspaces: vi.fn(),
   createWorkspace: vi.fn(),
+  fetchWorkspaceMembers: vi.fn(),
+  addWorkspaceMember: vi.fn(),
+  removeWorkspaceMember: vi.fn(),
+}));
+
+vi.mock("@/lib/api/admin", () => ({
+  fetchAdminUsers: vi.fn(),
 }));
 
 const fetchUserWorkspacesMock = vi.mocked(fetchUserWorkspaces);
 const createWorkspaceMock = vi.mocked(createWorkspace);
+const fetchWorkspaceMembersMock = vi.mocked(fetchWorkspaceMembers);
 
-const baseWorkspace: UserWorkspace = {
+const workspaceA: UserWorkspace = {
   id: "workspace-1",
   name: "Personal Workspace",
   ownerId: "owner-1",
@@ -55,45 +45,93 @@ const baseWorkspace: UserWorkspace = {
   createdAt: "2026-01-01T00:00:00.000Z",
 };
 
+const workspaceB: UserWorkspace = {
+  id: "workspace-2",
+  name: "Client Workspace",
+  ownerId: "owner-2",
+  role: WorkspaceMemberRole.ADMIN,
+  createdAt: "2026-01-02T00:00:00.000Z",
+};
+
+const membersA: WorkspaceMemberEntry[] = [
+  {
+    workspaceId: "workspace-1",
+    userId: "user-a",
+    role: WorkspaceMemberRole.OWNER,
+    joinedAt: "2026-01-03T00:00:00.000Z",
+    user: {
+      id: "user-a",
+      email: "alice@example.com",
+      name: "Alice",
+      image: null,
+    },
+  },
+];
+
+const membersB: WorkspaceMemberEntry[] = [
+  {
+    workspaceId: "workspace-2",
+    userId: "user-b",
+    role: WorkspaceMemberRole.MEMBER,
+    joinedAt: "2026-01-04T00:00:00.000Z",
+    user: {
+      id: "user-b",
+      email: "bob@example.com",
+      name: "Bob",
+      image: null,
+    },
+  },
+];
+
 describe("WorkspacesPage", () => {
   beforeEach(() => {
     vi.clearAllMocks();
   });
 
-  it("loads and renders user workspaces from the API", async () => {
-    fetchUserWorkspacesMock.mockResolvedValue([baseWorkspace]);
+  it("loads workspaces and fetches members for the first workspace", async () => {
+    fetchUserWorkspacesMock.mockResolvedValue([workspaceA, workspaceB]);
+    fetchWorkspaceMembersMock.mockResolvedValue(membersA);
 
     render(<WorkspacesPage />);
 
-    expect(screen.getByText("Loading workspaces...")).toBeInTheDocument();
+    expect(await screen.findByText("Your Workspaces (2)")).toBeInTheDocument();
+    expect(await screen.findByText("Personal Workspace Members")).toBeInTheDocument();
 
-    expect(await screen.findByText("Your Workspaces (1)")).toBeInTheDocument();
-    expect(screen.getByTestId("workspace-card")).toHaveTextContent("Personal Workspace");
-    expect(fetchUserWorkspacesMock).toHaveBeenCalledTimes(1);
+    await waitFor(() => {
+      expect(fetchWorkspaceMembersMock).toHaveBeenCalledWith("workspace-1");
+    });
+
+    expect(screen.getByText("alice@example.com")).toBeInTheDocument();
   });
 
-  it("shows fetch errors in the UI", async () => {
-    fetchUserWorkspacesMock.mockRejectedValue(new Error("Unable to load workspaces"));
+  it("switches selected workspace and reloads member list", async () => {
+    fetchUserWorkspacesMock.mockResolvedValue([workspaceA, workspaceB]);
+    fetchWorkspaceMembersMock.mockResolvedValueOnce(membersA).mockResolvedValueOnce(membersB);
 
+    const user = userEvent.setup();
     render(<WorkspacesPage />);
 
-    expect(await screen.findByText("Unable to load workspaces")).toBeInTheDocument();
+    expect(await screen.findByText("Personal Workspace Members")).toBeInTheDocument();
+
+    await user.click(screen.getByRole("button", { name: /client workspace/i }));
+
+    await waitFor(() => {
+      expect(fetchWorkspaceMembersMock).toHaveBeenLastCalledWith("workspace-2");
+    });
+
+    expect(await screen.findByText("Client Workspace Members")).toBeInTheDocument();
+    expect(screen.getByText("bob@example.com")).toBeInTheDocument();
   });
 
   it("creates a workspace and refreshes the list", async () => {
-    fetchUserWorkspacesMock.mockResolvedValueOnce([baseWorkspace]).mockResolvedValueOnce([
-      baseWorkspace,
-      {
-        ...baseWorkspace,
-        id: "workspace-2",
-        name: "New Workspace",
-        role: WorkspaceMemberRole.MEMBER,
-      },
-    ]);
+    fetchUserWorkspacesMock
+      .mockResolvedValueOnce([workspaceA])
+      .mockResolvedValueOnce([workspaceA, workspaceB]);
+    fetchWorkspaceMembersMock.mockResolvedValue(membersA);
     createWorkspaceMock.mockResolvedValue({
       id: "workspace-2",
-      name: "New Workspace",
-      ownerId: "owner-1",
+      name: "Client Workspace",
+      ownerId: "owner-2",
       settings: {},
       createdAt: "2026-01-02T00:00:00.000Z",
       updatedAt: "2026-01-02T00:00:00.000Z",
@@ -105,31 +143,17 @@ describe("WorkspacesPage", () => {
 
     expect(await screen.findByText("Your Workspaces (1)")).toBeInTheDocument();
 
-    await user.type(screen.getByPlaceholderText("Enter workspace name..."), "New Workspace");
+    await user.type(screen.getByPlaceholderText("Enter workspace name..."), "Client Workspace");
     await user.click(screen.getByRole("button", { name: "Create Workspace" }));
 
     await waitFor(() => {
-      expect(createWorkspaceMock).toHaveBeenCalledWith({ name: "New Workspace" });
+      expect(createWorkspaceMock).toHaveBeenCalledWith({ name: "Client Workspace" });
     });
+
     await waitFor(() => {
       expect(fetchUserWorkspacesMock).toHaveBeenCalledTimes(2);
     });
 
     expect(await screen.findByText("Your Workspaces (2)")).toBeInTheDocument();
   });
-
-  it("shows create errors in the UI", async () => {
-    fetchUserWorkspacesMock.mockResolvedValue([baseWorkspace]);
-    createWorkspaceMock.mockRejectedValue(new Error("Workspace creation failed"));
-
-    const user = userEvent.setup();
-    render(<WorkspacesPage />);
-
-    expect(await screen.findByText("Your Workspaces (1)")).toBeInTheDocument();
-
-    await user.type(screen.getByPlaceholderText("Enter workspace name..."), "Bad Workspace");
-    await user.click(screen.getByRole("button", { name: "Create Workspace" }));
-
-    expect(await screen.findByText("Workspace creation failed")).toBeInTheDocument();
-  });
 });
diff --git a/apps/web/src/app/(authenticated)/settings/workspaces/page.tsx b/apps/web/src/app/(authenticated)/settings/workspaces/page.tsx
index d50761e..58d06ab 100644
--- a/apps/web/src/app/(authenticated)/settings/workspaces/page.tsx
+++ b/apps/web/src/app/(authenticated)/settings/workspaces/page.tsx
@@ -2,10 +2,51 @@
 
 import type { ReactElement, SyntheticEvent } from "react";
 
-import { useCallback, useEffect, useState } from "react";
-import { WorkspaceCard } from "@/components/workspace/WorkspaceCard";
-import { createWorkspace, fetchUserWorkspaces, type UserWorkspace } from "@/lib/api/workspaces";
+import { useCallback, useEffect, useMemo, useState } from "react";
 import Link from "next/link";
+import { UserPlus, UserX } from "lucide-react";
+import { WorkspaceMemberRole } from "@mosaic/shared";
+import { Badge } from "@/components/ui/badge";
+import { Button } from "@/components/ui/button";
+import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle,
+  DialogTrigger,
+} from "@/components/ui/dialog";
+import {
+  AlertDialog,
+  AlertDialogAction,
+  AlertDialogCancel,
+  AlertDialogContent,
+  AlertDialogDescription,
+  AlertDialogFooter,
+  AlertDialogHeader,
+  AlertDialogTitle,
+} from "@/components/ui/alert-dialog";
+import { Input } from "@/components/ui/input";
+import { Label } from "@/components/ui/label";
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue,
+} from "@/components/ui/select";
+import {
+  addWorkspaceMember,
+  createWorkspace,
+  fetchUserWorkspaces,
+  fetchWorkspaceMembers,
+  removeWorkspaceMember,
+  type UserWorkspace,
+  type WorkspaceMemberEntry,
+} from "@/lib/api/workspaces";
+import { fetchAdminUsers, type AdminUser } from "@/lib/api/admin";
 
 function getErrorMessage(error: unknown, fallback: string): string {
   if (error instanceof Error) {
@@ -15,18 +56,53 @@ function getErrorMessage(error: unknown, fallback: string): string {
   return fallback;
 }
 
-/**
- * Workspaces Page
- * Fetches and creates workspaces through the real API.
- */
+function toRoleLabel(role: WorkspaceMemberRole): string {
+  return `${role.charAt(0)}${role.slice(1).toLowerCase()}`;
+}
+
+interface RemoveMemberTarget {
+  userId: string;
+  email: string;
+}
+
+const ROLE_BADGE_CLASS: Record<WorkspaceMemberRole, string> = {
+  [WorkspaceMemberRole.OWNER]: "border-purple-200 bg-purple-50 text-purple-700",
+  [WorkspaceMemberRole.ADMIN]: "border-blue-200 bg-blue-50 text-blue-700",
+  [WorkspaceMemberRole.MEMBER]: "border-green-200 bg-green-50 text-green-700",
+  [WorkspaceMemberRole.GUEST]: "border-gray-200 bg-gray-50 text-gray-700",
+};
+
 export default function WorkspacesPage(): ReactElement {
   const [workspaces, setWorkspaces] = useState<UserWorkspace[]>([]);
+  const [selectedWorkspaceId, setSelectedWorkspaceId] = useState<string | null>(null);
+
   const [isLoading, setIsLoading] = useState(true);
   const [loadError, setLoadError] = useState<string | null>(null);
+
   const [isCreating, setIsCreating] = useState(false);
   const [newWorkspaceName, setNewWorkspaceName] = useState("");
   const [createError, setCreateError] = useState<string | null>(null);
 
+  const [members, setMembers] = useState<WorkspaceMemberEntry[]>([]);
+  const [isMembersLoading, setIsMembersLoading] = useState(false);
+  const [membersError, setMembersError] = useState<string | null>(null);
+
+  const [isAddMemberOpen, setIsAddMemberOpen] = useState(false);
+  const [isAddingMember, setIsAddingMember] = useState(false);
+  const [addMemberError, setAddMemberError] = useState<string | null>(null);
+  const [memberUserId, setMemberUserId] = useState<string>("");
+  const [memberRole, setMemberRole] = useState<WorkspaceMemberRole>(WorkspaceMemberRole.MEMBER);
+  const [availableUsers, setAvailableUsers] = useState<AdminUser[]>([]);
+  const [isLoadingUsers, setIsLoadingUsers] = useState(false);
+
+  const [removeTarget, setRemoveTarget] = useState<RemoveMemberTarget | null>(null);
+  const [isRemovingMember, setIsRemovingMember] = useState(false);
+
+  const selectedWorkspace = useMemo(
+    () => workspaces.find((workspace) => workspace.id === selectedWorkspaceId) ?? null,
+    [selectedWorkspaceId, workspaces]
+  );
+
   const loadWorkspaces = useCallback(async (): Promise<void> => {
     setIsLoading(true);
 
@@ -34,31 +110,57 @@ export default function WorkspacesPage(): ReactElement {
       const data = await fetchUserWorkspaces();
       setWorkspaces(data);
       setLoadError(null);
+      setSelectedWorkspaceId((current) => {
+        if (current && data.some((workspace) => workspace.id === current)) {
+          return current;
+        }
+
+        return data[0]?.id ?? null;
+      });
     } catch (error) {
       setLoadError(getErrorMessage(error, "Failed to load workspaces"));
+      setSelectedWorkspaceId(null);
     } finally {
       setIsLoading(false);
     }
   }, []);
 
+  const loadMembers = useCallback(async (workspaceId: string): Promise<void> => {
+    setIsMembersLoading(true);
+    setMembersError(null);
+
+    try {
+      const data = await fetchWorkspaceMembers(workspaceId);
+      setMembers(data);
+    } catch (error) {
+      setMembersError(getErrorMessage(error, "Failed to load workspace members"));
+      setMembers([]);
+    } finally {
+      setIsMembersLoading(false);
+    }
+  }, []);
+
   useEffect(() => {
     void loadWorkspaces();
   }, [loadWorkspaces]);
 
-  const workspacesWithRoles = workspaces.map((workspace) => ({
-    ...workspace,
-    settings: {},
-    createdAt: new Date(workspace.createdAt),
-    updatedAt: new Date(workspace.createdAt),
-    userRole: workspace.role,
-    memberCount: 1,
-  }));
+  useEffect(() => {
+    if (!selectedWorkspaceId) {
+      setMembers([]);
+      setMembersError(null);
+      return;
+    }
 
-  const handleCreateWorkspace = async (e: SyntheticEvent<HTMLFormElement>): Promise<void> => {
-    e.preventDefault();
+    void loadMembers(selectedWorkspaceId);
+  }, [loadMembers, selectedWorkspaceId]);
+
+  const handleCreateWorkspace = async (event: SyntheticEvent<HTMLFormElement>): Promise<void> => {
+    event.preventDefault();
 
     const workspaceName = newWorkspaceName.trim();
-    if (!workspaceName) return;
+    if (!workspaceName) {
+      return;
+    }
 
     setIsCreating(true);
     setCreateError(null);
@@ -74,91 +176,394 @@ export default function WorkspacesPage(): ReactElement {
     }
   };
 
+  const eligibleUsers = useMemo(() => {
+    const memberIds = new Set(members.map((member) => member.userId));
+    return availableUsers.filter((user) => !memberIds.has(user.id));
+  }, [availableUsers, members]);
+
+  const loadAvailableUsers = useCallback(async (): Promise<void> => {
+    setIsLoadingUsers(true);
+
+    try {
+      const response = await fetchAdminUsers(1, 200);
+      const activeUsers = response.data.filter((user) => user.deactivatedAt === null);
+      setAvailableUsers(activeUsers);
+
+      if (memberUserId && activeUsers.some((user) => user.id === memberUserId)) {
+        return;
+      }
+
+      const memberIds = new Set(members.map((member) => member.userId));
+      const firstEligible = activeUsers.find((user) => !memberIds.has(user.id));
+      setMemberUserId(firstEligible?.id ?? "");
+    } catch (error) {
+      setAddMemberError(getErrorMessage(error, "Failed to load users for member assignment"));
+      setAvailableUsers([]);
+      setMemberUserId("");
+    } finally {
+      setIsLoadingUsers(false);
+    }
+  }, [memberUserId, members]);
+
+  const openAddMemberDialog = async (): Promise<void> => {
+    setAddMemberError(null);
+    setMemberRole(WorkspaceMemberRole.MEMBER);
+    setIsAddMemberOpen(true);
+    await loadAvailableUsers();
+  };
+
+  const handleAddMember = async (event: SyntheticEvent<HTMLFormElement>): Promise<void> => {
+    event.preventDefault();
+
+    if (!selectedWorkspaceId) {
+      setAddMemberError("Select a workspace before adding members.");
+      return;
+    }
+
+    if (!memberUserId) {
+      setAddMemberError("Select a user to add.");
+      return;
+    }
+
+    setIsAddingMember(true);
+    setAddMemberError(null);
+
+    try {
+      await addWorkspaceMember(selectedWorkspaceId, {
+        userId: memberUserId,
+        role: memberRole,
+      });
+      setIsAddMemberOpen(false);
+      await loadMembers(selectedWorkspaceId);
+    } catch (error) {
+      setAddMemberError(getErrorMessage(error, "Failed to add member"));
+    } finally {
+      setIsAddingMember(false);
+    }
+  };
+
+  const handleRemoveMember = async (): Promise<void> => {
+    if (!selectedWorkspaceId || !removeTarget) {
+      return;
+    }
+
+    setIsRemovingMember(true);
+
+    try {
+      await removeWorkspaceMember(selectedWorkspaceId, removeTarget.userId);
+      setRemoveTarget(null);
+      await loadMembers(selectedWorkspaceId);
+    } catch (error) {
+      setMembersError(getErrorMessage(error, "Failed to remove member"));
+    } finally {
+      setIsRemovingMember(false);
+    }
+  };
+
   return (
-    <main className="container mx-auto px-4 py-8 max-w-5xl">
-      <div className="mb-8">
-        <div className="flex items-center justify-between mb-2">
-          <h1 className="text-3xl font-bold text-gray-900">Workspaces</h1>
-          <Link href="/settings" className="text-sm text-blue-600 hover:text-blue-700">
-            ← Back to Settings
-          </Link>
+    <main className="max-w-6xl mx-auto p-6 space-y-6">
+      <div className="flex items-start justify-between gap-4">
+        <div>
+          <h1 className="text-3xl font-bold">Workspaces</h1>
+          <p className="text-muted-foreground mt-1">Manage workspaces and workspace members</p>
         </div>
-        <p className="text-gray-600">Manage your workspaces and collaborate with your team</p>
+        <Link href="/settings" className="text-sm text-blue-600 hover:text-blue-700">
+          ← Back to Settings
+        </Link>
       </div>
 
-      {/* Create New Workspace */}
-      <div className="bg-white rounded-lg shadow-sm border border-gray-200 p-6 mb-6">
-        <h2 className="text-lg font-semibold text-gray-900 mb-4">Create New Workspace</h2>
-        <form onSubmit={handleCreateWorkspace} className="flex gap-3">
-          <input
-            type="text"
-            value={newWorkspaceName}
-            onChange={(e) => {
-              setNewWorkspaceName(e.target.value);
-            }}
-            placeholder="Enter workspace name..."
-            disabled={isCreating}
-            className="flex-1 px-4 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent disabled:bg-gray-100"
-          />
-          <button
-            type="submit"
-            disabled={isCreating || !newWorkspaceName.trim()}
-            className="px-6 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700 disabled:opacity-50 disabled:cursor-not-allowed font-medium"
-          >
-            {isCreating ? "Creating..." : "Create Workspace"}
-          </button>
-        </form>
-        {createError !== null && (
-          <div className="mt-3 rounded-md border border-red-200 bg-red-50 px-3 py-2 text-sm text-red-700">
-            {createError}
-          </div>
-        )}
+      <Card>
+        <CardHeader>
+          <CardTitle>Create New Workspace</CardTitle>
+          <CardDescription>Create a workspace for a new team or project.</CardDescription>
+        </CardHeader>
+        <CardContent>
+          <form onSubmit={handleCreateWorkspace} className="flex gap-3">
+            <Input
+              type="text"
+              value={newWorkspaceName}
+              onChange={(event) => {
+                setNewWorkspaceName(event.target.value);
+              }}
+              placeholder="Enter workspace name..."
+              disabled={isCreating}
+            />
+            <Button type="submit" disabled={isCreating || !newWorkspaceName.trim()}>
+              {isCreating ? "Creating..." : "Create Workspace"}
+            </Button>
+          </form>
+          {createError !== null ? (
+            <p className="mt-3 text-sm text-destructive" role="alert">
+              {createError}
+            </p>
+          ) : null}
+        </CardContent>
+      </Card>
+
+      {loadError !== null ? (
+        <Card>
+          <CardContent className="py-4">
+            <p className="text-sm text-destructive" role="alert">
+              {loadError}
+            </p>
+          </CardContent>
+        </Card>
+      ) : null}
+
+      <div className="grid grid-cols-1 lg:grid-cols-5 gap-6">
+        <Card className="lg:col-span-2">
+          <CardHeader>
+            <CardTitle>Your Workspaces ({isLoading ? "..." : workspaces.length})</CardTitle>
+            <CardDescription>Click a workspace to manage its members.</CardDescription>
+          </CardHeader>
+          <CardContent className="space-y-3">
+            {isLoading ? (
+              <p className="text-sm text-muted-foreground">Loading workspaces...</p>
+            ) : workspaces.length === 0 ? (
+              <p className="text-sm text-muted-foreground">
+                No workspaces yet. Create one to begin.
+              </p>
+            ) : (
+              workspaces.map((workspace) => {
+                const isSelected = selectedWorkspaceId === workspace.id;
+
+                return (
+                  <button
+                    key={workspace.id}
+                    type="button"
+                    onClick={() => {
+                      setSelectedWorkspaceId(workspace.id);
+                    }}
+                    className={`w-full rounded-lg border p-4 text-left transition-colors ${
+                      isSelected ? "border-primary bg-muted/40" : "border-border hover:bg-muted/20"
+                    }`}
+                  >
+                    <div className="flex items-start justify-between gap-3">
+                      <div className="min-w-0">
+                        <p className="font-semibold truncate">{workspace.name}</p>
+                        <p className="text-xs text-muted-foreground mt-1">
+                          Created {new Date(workspace.createdAt).toLocaleDateString()}
+                        </p>
+                      </div>
+                      <Badge variant="outline">{toRoleLabel(workspace.role)}</Badge>
+                    </div>
+                  </button>
+                );
+              })
+            )}
+          </CardContent>
+        </Card>
+
+        <Card className="lg:col-span-3">
+          <CardHeader>
+            <div className="flex items-start justify-between gap-3">
+              <div>
+                <CardTitle>
+                  {selectedWorkspace ? `${selectedWorkspace.name} Members` : "Workspace Members"}
+                </CardTitle>
+                <CardDescription>
+                  {selectedWorkspace
+                    ? "Manage member roles and access for this workspace."
+                    : "Select a workspace to view its members."}
+                </CardDescription>
+              </div>
+
+              <Dialog
+                open={isAddMemberOpen}
+                onOpenChange={(open) => {
+                  if (!open && !isAddingMember) {
+                    setIsAddMemberOpen(false);
+                    setAddMemberError(null);
+                  }
+                }}
+              >
+                <DialogTrigger asChild>
+                  <Button
+                    onClick={() => {
+                      void openAddMemberDialog();
+                    }}
+                    disabled={!selectedWorkspace}
+                  >
+                    <UserPlus className="h-4 w-4 mr-2" />
+                    Add Member
+                  </Button>
+                </DialogTrigger>
+                <DialogContent>
+                  <DialogHeader>
+                    <DialogTitle>Add Workspace Member</DialogTitle>
+                    <DialogDescription>
+                      Add an existing user to {selectedWorkspace?.name ?? "this workspace"}.
+                    </DialogDescription>
+                  </DialogHeader>
+
+                  <form
+                    onSubmit={(event) => {
+                      void handleAddMember(event);
+                    }}
+                    className="space-y-4"
+                  >
+                    <div className="space-y-2">
+                      <Label htmlFor="member-user">User</Label>
+                      <Select
+                        value={memberUserId}
+                        onValueChange={(value) => {
+                          setMemberUserId(value);
+                        }}
+                        disabled={isLoadingUsers || eligibleUsers.length === 0 || isAddingMember}
+                      >
+                        <SelectTrigger id="member-user">
+                          <SelectValue
+                            placeholder={
+                              isLoadingUsers
+                                ? "Loading users..."
+                                : eligibleUsers.length === 0
+                                  ? "No eligible users"
+                                  : "Select a user"
+                            }
+                          />
+                        </SelectTrigger>
+                        <SelectContent>
+                          {eligibleUsers.map((user) => (
+                            <SelectItem key={user.id} value={user.id}>
+                              {user.name} ({user.email})
+                            </SelectItem>
+                          ))}
+                        </SelectContent>
+                      </Select>
+                    </div>
+
+                    <div className="space-y-2">
+                      <Label htmlFor="member-role">Role</Label>
+                      <Select
+                        value={memberRole}
+                        onValueChange={(value) => {
+                          setMemberRole(value as WorkspaceMemberRole);
+                        }}
+                        disabled={isAddingMember}
+                      >
+                        <SelectTrigger id="member-role">
+                          <SelectValue placeholder="Select role" />
+                        </SelectTrigger>
+                        <SelectContent>
+                          {Object.values(WorkspaceMemberRole)
+                            .filter((role) => role !== WorkspaceMemberRole.OWNER)
+                            .map((role) => (
+                              <SelectItem key={role} value={role}>
+                                {toRoleLabel(role)}
+                              </SelectItem>
+                            ))}
+                        </SelectContent>
+                      </Select>
+                    </div>
+
+                    {addMemberError !== null ? (
+                      <p className="text-sm text-destructive" role="alert">
+                        {addMemberError}
+                      </p>
+                    ) : null}
+
+                    <DialogFooter>
+                      <Button
+                        type="button"
+                        variant="outline"
+                        onClick={() => {
+                          if (!isAddingMember) {
+                            setIsAddMemberOpen(false);
+                            setAddMemberError(null);
+                          }
+                        }}
+                        disabled={isAddingMember}
+                      >
+                        Cancel
+                      </Button>
+                      <Button type="submit" disabled={isAddingMember || !memberUserId}>
+                        {isAddingMember ? "Adding..." : "Add Member"}
+                      </Button>
+                    </DialogFooter>
+                  </form>
+                </DialogContent>
+              </Dialog>
+            </div>
+          </CardHeader>
+
+          <CardContent className="space-y-3">
+            {selectedWorkspace === null ? (
+              <p className="text-sm text-muted-foreground">Select a workspace to view members.</p>
+            ) : membersError !== null ? (
+              <p className="text-sm text-destructive" role="alert">
+                {membersError}
+              </p>
+            ) : isMembersLoading ? (
+              <p className="text-sm text-muted-foreground">Loading members...</p>
+            ) : members.length === 0 ? (
+              <p className="text-sm text-muted-foreground">No members found for this workspace.</p>
+            ) : (
+              members.map((member) => (
+                <div
+                  key={member.userId}
+                  className="rounded-md border p-4 flex flex-col gap-3 md:flex-row md:items-center md:justify-between"
+                >
+                  <div className="space-y-1 min-w-0">
+                    <p className="font-semibold truncate">{member.user.name ?? "Unnamed User"}</p>
+                    <p className="text-sm text-muted-foreground truncate">{member.user.email}</p>
+                  </div>
+
+                  <div className="flex items-center gap-2 md:justify-end">
+                    <Badge variant="outline" className={ROLE_BADGE_CLASS[member.role]}>
+                      {toRoleLabel(member.role)}
+                    </Badge>
+
+                    <Button
+                      type="button"
+                      variant="destructive"
+                      size="sm"
+                      onClick={() => {
+                        setRemoveTarget({
+                          userId: member.userId,
+                          email: member.user.email,
+                        });
+                      }}
+                    >
+                      <UserX className="h-4 w-4 mr-2" />
+                      Remove
+                    </Button>
+                  </div>
+                </div>
+              ))
+            )}
+          </CardContent>
+        </Card>
       </div>
 
-      {/* Workspace List */}
-      <div className="space-y-4">
-        <h2 className="text-xl font-semibold text-gray-900">
-          Your Workspaces ({isLoading ? "..." : workspacesWithRoles.length})
-        </h2>
-        {loadError !== null ? (
-          <div className="rounded-md border border-red-200 bg-red-50 px-4 py-3 text-red-700">
-            {loadError}
-          </div>
-        ) : isLoading ? (
-          <div className="bg-white rounded-lg shadow-sm border border-gray-200 p-12 text-center text-gray-600">
-            Loading workspaces...
-          </div>
-        ) : workspacesWithRoles.length === 0 ? (
-          <div className="bg-white rounded-lg shadow-sm border border-gray-200 p-12 text-center">
-            <svg
-              className="mx-auto h-12 w-12 text-gray-400 mb-4"
-              fill="none"
-              stroke="currentColor"
-              viewBox="0 0 24 24"
+      <AlertDialog
+        open={removeTarget !== null}
+        onOpenChange={(open) => {
+          if (!open && !isRemovingMember) {
+            setRemoveTarget(null);
+          }
+        }}
+      >
+        <AlertDialogContent>
+          <AlertDialogHeader>
+            <AlertDialogTitle>Remove Workspace Member</AlertDialogTitle>
+            <AlertDialogDescription>
+              Remove {removeTarget?.email} from {selectedWorkspace?.name}? They will lose access to
+              this workspace.
+            </AlertDialogDescription>
+          </AlertDialogHeader>
+          <AlertDialogFooter>
+            <AlertDialogCancel disabled={isRemovingMember}>Cancel</AlertDialogCancel>
+            <AlertDialogAction
+              disabled={isRemovingMember}
+              onClick={() => {
+                void handleRemoveMember();
+              }}
             >
-              <path
-                strokeLinecap="round"
-                strokeLinejoin="round"
-                strokeWidth={2}
-                d="M19 21V5a2 2 0 00-2-2H7a2 2 0 00-2 2v16m14 0h2m-2 0h-5m-9 0H3m2 0h5M9 7h1m-1 4h1m4-4h1m-1 4h1m-5 10v-5a1 1 0 011-1h2a1 1 0 011 1v5m-4 0h4"
-              />
-            </svg>
-            <h3 className="text-lg font-medium text-gray-900 mb-2">No workspaces yet</h3>
-            <p className="text-gray-600">Create your first workspace to get started</p>
-          </div>
-        ) : (
-          <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
-            {workspacesWithRoles.map((workspace) => (
-              <WorkspaceCard
-                key={workspace.id}
-                workspace={workspace}
-                userRole={workspace.userRole}
-                memberCount={workspace.memberCount}
-              />
-            ))}
-          </div>
-        )}
-      </div>
+              {isRemovingMember ? "Removing..." : "Remove"}
+            </AlertDialogAction>
+          </AlertDialogFooter>
+        </AlertDialogContent>
+      </AlertDialog>
     </main>
   );
 }
diff --git a/apps/web/src/lib/api/admin.ts b/apps/web/src/lib/api/admin.ts
index cb032ac..4ecc3aa 100644
--- a/apps/web/src/lib/api/admin.ts
+++ b/apps/web/src/lib/api/admin.ts
@@ -53,6 +53,7 @@ export interface InvitationResponse {
 
 export interface UpdateUserDto {
   name?: string;
+  email?: string;
   deactivatedAt?: string | null;
   emailVerified?: boolean;
   preferences?: Record<string, unknown>;