diff --git a/packages/server/src/index.ts b/packages/server/src/index.ts
index 45f6d10..0d47965 100644
--- a/packages/server/src/index.ts
+++ b/packages/server/src/index.ts
@@ -172,7 +172,9 @@ function roomInfo(room: Room) {
     hostId: room.hostId,
     started: room.state !== null,
     colors: Object.fromEntries(room.colorChoices),
-    bots: Object.fromEntries(room.bots),
+    bots: Object.fromEntries(
+      [...room.bots].map(([name, b]) => [name, b.secret ? "mystery" : b.style]),
+    ),
   };
 }
 
diff --git a/packages/server/src/rooms.ts b/packages/server/src/rooms.ts
index f5dfecc..6d2819e 100644
--- a/packages/server/src/rooms.ts
+++ b/packages/server/src/rooms.ts
@@ -47,8 +47,8 @@ export interface Room {
   events: GameEvent[]; // full history (unredacted — redact per recipient)
   /** Table talk, persisted with the room (public to all seats). */
   chat: { player: PlayerId; text: string; at: string }[];
-  /** Seats the server itself plays, and each one's temperament. */
-  bots: Map<PlayerId, AutomatonStyle>;
+  /** Seats the server itself plays: temperament, and whether it is told. */
+  bots: Map<PlayerId, { style: AutomatonStyle; secret: boolean }>;
 }
 
 const rooms = new Map<string, Room>();
@@ -247,12 +247,14 @@ export function addAutomaton(room: Room, styleWanted?: string): { name: PlayerId
   if (room.players.length >= 6) return { error: "room is full" };
   const name = AUTOMATON_NAMES.find((n) => !room.players.includes(n));
   if (!name) return { error: "the workshop is empty" };
-  const style: AutomatonStyle = AUTOMATON_STYLES.includes(styleWanted as AutomatonStyle)
+  const known = AUTOMATON_STYLES.includes(styleWanted as AutomatonStyle);
+  const style: AutomatonStyle = known
     ? (styleWanted as AutomatonStyle)
     : AUTOMATON_STYLES[randomInt(AUTOMATON_STYLES.length)]!;
+  const secret = !known; // the mystery machine keeps its mood to itself
   room.players.push(name);
-  room.bots.set(name, style);
-  appendLine(room.id, { kind: "join", name, bot: true, style });
+  room.bots.set(name, { style, secret });
+  appendLine(room.id, { kind: "join", name, bot: true, style, ...(secret ? { secret: true } : {}) });
   return { name };
 }
 
@@ -277,7 +279,7 @@ export function driveOneAutomaton(room: Room): { seat: PlayerId; events: GameEve
   const seat = actingSeat(room);
   if (!seat || !room.bots.has(seat)) return null;
   const view = viewFor(room.state!, seat);
-  const cmd = automatonCommand(view, room.bots.get(seat)) ?? automatonFallback(view);
+  const cmd = automatonCommand(view, room.bots.get(seat)?.style) ?? automatonFallback(view);
   let r = runCommand(room, seat, cmd);
   if ("error" in r) {
     r = runCommand(room, seat, automatonFallback(view));
@@ -494,7 +496,10 @@ export function loadPersistedRooms(): void {
         if (line.kind === "join") {
           if (line.bot) {
             room.players.push(line.name);
-            room.bots.set(line.name, (line.style as AutomatonStyle) ?? "hunter");
+            room.bots.set(line.name, {
+              style: (line.style as AutomatonStyle) ?? "hunter",
+              secret: line.secret === true,
+            });
           } else {
             const joinHash = line.tokenHash ?? (line.token ? hashToken(line.token) : null);
             if (!joinHash) throw new Error("join line has no token");
diff --git a/packages/server/src/store.ts b/packages/server/src/store.ts
index f63d107..6a3f71d 100644
--- a/packages/server/src/store.ts
+++ b/packages/server/src/store.ts
@@ -28,6 +28,8 @@ export interface JoinLine {
   bot?: true;
   /** The automaton's temperament. */
   style?: string;
+  /** A mystery machine: the temperament is not revealed to the table. */
+  secret?: true;
 }
 
 export interface StartLine {
diff --git a/packages/web/src/App.svelte b/packages/web/src/App.svelte
index 49a7739..3018e63 100644
--- a/packages/web/src/App.svelte
+++ b/packages/web/src/App.svelte
@@ -1055,7 +1055,7 @@
               <button class="stamp tiny" onclick={() => net.addBot("hunter")}>hunter</button>
               <button class="stamp tiny" onclick={() => net.addBot("berserker")}>berserker</button>
               <button class="stamp tiny" onclick={() => net.addBot("worrier")}>worrier</button>
-              <button class="stamp tiny" onclick={() => net.addBot()}>random</button>
+              <button class="stamp tiny" onclick={() => net.addBot()}>mystery</button>
             </span>
           {/if}
           <label class="check">