diff --git a/.lane/memory/apps/host/src/directory.ts/01M4YX72YG7JQ8ACP15VM1V6XB-every-directory-request-must.md b/.lane/memory/apps/host/src/directory.ts/01M4YX72YG7JQ8ACP15VM1V6XB-every-directory-request-must.md
index 0b67a279..f9306f11 100644
--- a/.lane/memory/apps/host/src/directory.ts/01M4YX72YG7JQ8ACP15VM1V6XB-every-directory-request-must.md
+++ b/.lane/memory/apps/host/src/directory.ts/01M4YX72YG7JQ8ACP15VM1V6XB-every-directory-request-must.md
@@ -4,9 +4,9 @@ anchor: function call
 created: 2026-10-15T04:30:36Z
 norm: '1'
 sig: 3b9d360bb018f164
-body_hash: ed032412ce991b6b
-raw_hash: 17ca2b8a23ffb09d
-vouched: 2026-10-22T14:33:26Z
+body_hash: fd35da8da75facb4
+raw_hash: 366b10d619b52eba
+vouched: 2026-10-22T20:38:32Z
 lines: 97-125
 ---
 
diff --git a/.lane/memory/apps/host/src/directory.ts/01M5JNCCJHPCRSGY5EFTASKNDP-a-served-directory-s-mac-is.md b/.lane/memory/apps/host/src/directory.ts/01M5JNCCJHPCRSGY5EFTASKNDP-a-served-directory-s-mac-is.md
new file mode 100644
index 00000000..fe24dba2
--- /dev/null
+++ b/.lane/memory/apps/host/src/directory.ts/01M5JNCCJHPCRSGY5EFTASKNDP-a-served-directory-s-mac-is.md
@@ -0,0 +1,12 @@
+---
+id: 01M5JNCCJHPCRSGY5EFTASKNDP
+anchor: function server
+created: 2026-10-22T20:38:30Z
+norm: '1'
+sig: 128e3397d58bcc17
+body_hash: 9d1be79086813df2
+raw_hash: b33a79c8a848f2a2
+lines: 240-243
+---
+
+a served directory's Mac is found by the address it publishes; a deployed directory matches none and keeps the generic error
diff --git a/apps/app/src/directory-settings.tsx b/apps/app/src/directory-settings.tsx
index 0f2035a4..1ee35203 100644
--- a/apps/app/src/directory-settings.tsx
+++ b/apps/app/src/directory-settings.tsx
@@ -8,8 +8,8 @@ import { host } from "./host";
 import { useDiagnostics } from "./host-settings";
 import { parse } from "./invite";
 import { CREATE_DIRECTORY, DIRECTORY_CHANGED, People, useRoster } from "./onboarding";
-import { Confirm, Group, Page, Problem, Row, Status, Value } from "./settings-layout";
-import { TEAM_SETUP } from "./team-setup";
+import { Confirm, Group, Page, Problem, Row, Status, Value, when } from "./settings-layout";
+import { DirectoryHosts, TEAM_SETUP } from "./team-setup";
 
 const SETUP = "https://github.com/githubnext/ace/blob/main/docs/setup.md#team-directory";
 
@@ -107,6 +107,11 @@ export function TeamSettings({ active }: { active: boolean }) {
 					</>
 				)}
 			</Group>
+			{checked?.directory.url && (
+				<Group title="In the directory">
+					<DirectoryHosts directory={checked.directory} self={checked.tailscale.name} />
+				</Group>
+			)}
 			{checks.open && <TeamPeople />}
 			{checked?.directory.url && checked.directory.synced && !served(checked.directory) && (
 				<TeamServices services={checked.directory.services} />
@@ -194,14 +199,6 @@ function shared(shares: Share[]): string {
 	return [...projects].map(([name, people]) => `${name} with ${people.join(", ")}`).join("; ");
 }
 
-/** A time today, or a date and time when older, so a stale sync doesn't read as recent. */
-function when(time: number) {
-	const date = new Date(time);
-	return date.toDateString() === new Date().toDateString()
-		? date.toLocaleTimeString()
-		: date.toLocaleString();
-}
-
 /** `row` keeps each result beside the control that caused it. */
 type Action = { row?: "directory" | "secret"; busy?: string; error?: string; message?: string };
 
diff --git a/apps/app/src/settings-layout.tsx b/apps/app/src/settings-layout.tsx
index 8a0673ee..c9e57ff3 100644
--- a/apps/app/src/settings-layout.tsx
+++ b/apps/app/src/settings-layout.tsx
@@ -178,6 +178,14 @@ export function Confirm({ children, action, busy, onConfirm, onCancel }: {
 	);
 }
 
+/** A time today, or a date and time when older, so a stale sync doesn't read as recent. */
+export function when(time: number) {
+	const date = new Date(time);
+	return date.toDateString() === new Date().toDateString()
+		? date.toLocaleTimeString()
+		: date.toLocaleString();
+}
+
 export function Status({ children }: { children: ReactNode }) {
 	return <p role="status" className="text-xs/relaxed text-muted-foreground">{children}</p>;
 }
diff --git a/apps/app/src/team-setup.tsx b/apps/app/src/team-setup.tsx
index 508e75fe..10519003 100644
--- a/apps/app/src/team-setup.tsx
+++ b/apps/app/src/team-setup.tsx
@@ -13,11 +13,12 @@ import {
 	toast,
 } from "@ace/ui";
 import { IconArrowUpRight, IconCheck, IconCopy, IconLoader, IconUsers } from "@ace/ui/icons";
-import { TEAM_ASK_EXPIRES, type TeamPeer } from "@ace/host/protocol";
+import { type Diagnostics, TEAM_ASK_EXPIRES, type TeamPeer } from "@ace/host/protocol";
 
 import { host } from "./host";
 import { useDiagnostics } from "./host-settings";
 import { type Invite as Team, link, page, parse } from "./invite";
+import { Row, Status, Value, when } from "./settings-layout";
 
 const DOCS = "https://github.com/githubnext/ace/blob/main/docs/setup.md";
 export const TEAM_SETUP = "ace:team-setup";
@@ -68,6 +69,11 @@ export function TeamSetup({ github, invite, inviting, onClose }: {
 	const [provider, setProvider] = useState<Provider>("cloudflare");
 	const [joined, setJoined] = useState<Team>();
 	const [error, setError] = useState("");
+	const checks = useDiagnostics(step === "fork");
+	const checked = checks.value;
+	const directory = checked?.directory.url ? checked.directory : undefined;
+	// Until the host answers, the fork can't tell a first person from one already in a team.
+	const pending = checks.open && !checked && !checks.error;
 
 	useEffect(() => {
 		if (!inviting) return;
@@ -81,7 +87,31 @@ export function TeamSetup({ github, invite, inviting, onClose }: {
 		<Dialog open onOpenChange={next => next || onClose()}>
 			<DialogContent className="gap-4 sm:max-w-[34rem]">
 				{STEPS[step] && !inviting && <Steps current={step} />}
-				{step === "fork" && (
+				{step === "fork" && directory && (
+					<>
+						<Checks github={github} />
+						<Header
+							title="Your team"
+							description={directory.serving
+								? "This Mac serves your team's directory. Teammates on the tailnet join it on their own."
+								: `This Mac is in your team's directory at ${new URL(directory.url!).host}.`}
+						/>
+						<div className="flex flex-col divide-y divide-border/60 rounded-md border border-border/70 px-3">
+							<DirectoryHosts directory={directory} self={checked?.tailscale.name} />
+						</div>
+						<Nearby onJoined={onClose} team={new URL(directory.url!).host} />
+						<Footer
+							back={
+								<Button variant="ghost" onClick={() => setStep("directory")}>
+									List channels elsewhere…
+								</Button>
+							}
+							next={<Button onClick={onClose}>Done</Button>}
+						/>
+					</>
+				)}
+				{step === "fork" && pending && <Checks github={github} />}
+				{step === "fork" && !pending && !directory && (
 					<>
 						<Checks github={github} />
 						<Header
@@ -433,8 +463,9 @@ function useTeamPeers(): TeamPeer[] {
 const CLOCK = new Intl.DateTimeFormat(undefined, { timeStyle: "short" });
 
 /** Ask a teammate's host to let this one in; their owner approves in their Ace. */
-function Nearby({ onJoined }: { onJoined: () => void }) {
-	const peers = useTeamPeers();
+function Nearby({ onJoined, team }: { onJoined: () => void; team?: string }) {
+	// A teammate already in this host's directory has no other team to let it into.
+	const peers = useTeamPeers().filter((peer) => peer.team !== team);
 	// By host: the peer list is read again every few seconds, which replaces its objects.
 	const [asking, setAsking] = useState<{ host: string; who: string; lapses: number }>();
 	const [error, setError] = useState("");
@@ -722,3 +753,31 @@ export function Copyable(
 		</div>
 	);
 }
+
+/** Hosts that have joined the directory, and when each last published its channels there. */
+export function DirectoryHosts(
+	{ directory, self }: { directory: Diagnostics["directory"]; self?: string },
+) {
+	if (!directory.hosts?.length) {
+		return (
+			<div className="py-3">
+				<Status>
+					{directory.synced ? "No hosts have joined yet." : "Waiting for the directory…"}
+				</Status>
+			</div>
+		);
+	}
+	return (
+		<>
+			{directory.hosts?.map((host) => (
+				<Row
+					key={host.name}
+					label={host.name === self ? `${host.name} (this Mac)` : host.name}
+					description={host.github || host.login}
+				>
+					<Value>Synced {when(host.seen)}</Value>
+				</Row>
+			))}
+		</>
+	);
+}
diff --git a/apps/host/src/diagnostics.ts b/apps/host/src/diagnostics.ts
index e9df05b9..1cab67ff 100644
--- a/apps/host/src/diagnostics.ts
+++ b/apps/host/src/diagnostics.ts
@@ -52,7 +52,7 @@ export async function diagnostics(sync?: boolean): Promise<Diagnostics> {
 		Promise.all([git(), shell()]),
 		tailnet.diagnostics(started),
 	]);
-	const { hosted, app, compute } = directory.read();
+	const { hosted, app, compute, hosts } = directory.read();
 	return {
 		tools,
 		tailscale: config.loopback ? { ...tailscale, loopback: true } : tailscale,
@@ -62,6 +62,7 @@ export async function diagnostics(sync?: boolean): Promise<Diagnostics> {
 			services: { hosted, app, compute },
 			serving: served.isServing(),
 			shares: served.shares(),
+			hosts: hosts.map(({ address: _, ...host }) => host),
 		},
 		shell: { ...environment },
 		web: web.address,
diff --git a/apps/host/src/directory.ts b/apps/host/src/directory.ts
index b3285b12..100e6f2f 100644
--- a/apps/host/src/directory.ts
+++ b/apps/host/src/directory.ts
@@ -211,16 +211,37 @@ async function call(
 		});
 	} catch (cause) {
 		if (signal.aborted) throw cause;
-		throw new Error(`Could not reach ${base}. Check the URL and your connection.`, { cause });
+		const host = server(base);
+		throw new Error(
+			host
+				? `${host.name}, which serves the directory, is offline. Channels stay listed as they were.`
+				: `Could not reach ${base}. Check the URL and your connection.`,
+			{ cause },
+		);
 	}
 	if (response.status === 401) throw new Error(await rejection(response, "The directory"));
 	if (!response.ok) {
+		const host = server(base);
+		if (host && response.status === 404) {
+			throw new Error(
+				`${host.name} stopped serving the directory. Channels stay listed as they were.`,
+			);
+		}
 		const reason = await refusal(response, "The directory");
 		throw new Error(response.status < 500 ? `${reason} Check the URL.` : reason);
 	}
 	return response;
 }
 
+/**
+ * The teammate's host serving a tailnet directory, found by the address it publishes, so a failure
+ * names their Mac rather than blaming this one's connection. A deployed directory has none.
+ */
+function server(base: string): Host | undefined {
+	const address = new URL(base).hostname.replace(/^\[|\]$/g, "");
+	return known.hosts.find((host) => host.address === address);
+}
+
 type Options = {
 	self(): Omit<Host, "seen">;
 	channels(): Promise<Listing[]>;
diff --git a/apps/host/src/protocol.ts b/apps/host/src/protocol.ts
index 4e8c78a4..b9e5896d 100644
--- a/apps/host/src/protocol.ts
+++ b/apps/host/src/protocol.ts
@@ -68,6 +68,8 @@ export type Diagnostics = {
 		serving: boolean;
 		/** The project shares in the directory this host serves, which stopping it deletes. */
 		shares: Share[];
+		/** Hosts in the directory's last answer, and when each last published to it; older hosts omit it. */
+		hosts?: DirectoryHost[];
 	};
 	/** Whether the helper loaded the login shell's environment; `pending` while it retries. */
 	shell: { state: "adopted" | "pending" | "failed"; error?: string };
@@ -77,6 +79,9 @@ export type Diagnostics = {
 	http?: string;
 };
 
+/** A host in the team's directory; `seen` is when it last published there. */
+export type DirectoryHost = { name: string; login: string; github?: string; seen: number };
+
 /** `offline`: the channel's host is unreachable. Hosted channels are never offline. */
 export type ChannelState = "running" | "dormant" | "archived" | "offline";
 
diff --git a/docs/setup.md b/docs/setup.md
index 3845f4ba..2690ed6c 100644
--- a/docs/setup.md
+++ b/docs/setup.md
@@ -59,7 +59,9 @@ Create it in the app: the sidebar's Team directory card, an offline channel, or
 offers **Create directory**. **This Mac** serves it from this host on the tailnet, with no account
 or secret; a Mac that stays on (a Mac mini) is the best place for it. Every other host on the
 tailnet finds it in this host's hello and joins it on its own, unless it left a directory before.
-**Stop serving…** in `Settings → Team` turns it off and deletes its shares.
+**Stop serving…** in `Settings → Team` turns it off and deletes its shares. `Settings → Team` and
+**Team setup** list the hosts in the directory and when each last synced; when the Mac serving it is
+offline or stops serving, teammates' sync errors name that Mac.
 
 ### Deployed directory