Remove hints; gate undo/redo behind a setting and limit it to your turn

Three changes to how much the client helps you:

- The hint feature is gone -- button, board highlights, the whole path that asked
  the policy for your best move. Playing against the model shouldn't come with the
  model telling you what to do.

- Undo/redo is off by default and enabled from a menu toggle. Taking moves back is
  a training aid, not how the game is played, so the honest game is the default.
  The switch is reactive: flipping it on mid-game shows the controls immediately,
  no restart.

- When on, undo/redo is limited to the current turn. The floor is the most recent
  committed move -- a rival move or your own draw -- so you can revise a card
  selection or placement before you draw, but you can't rewind into the rival's
  move or an earlier turn. Verified in a browser: undo is disabled at turn start,
  enabled after selecting a card, and disabled again once you've drawn and the
  rival has answered.

Board and Card lose their now-dead hint props and the hint CSS goes with them.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XBQKgvBbxbheiTF1AVy1Sh

web/src/App.tsx

@@ -1,9 +1,8 @@
 import { useEffect, useMemo, useRef, useState } from "react";
 
-import { Board, type BoardHint } from "./components/Board";
+import { Board } from "./components/Board";
 import { Card, CardBack } from "./components/Card";
 import { ResultCard } from "./components/ResultCard";
-import { describeAction } from "./game/actions";
 import { cardColor, cardName } from "./game/cards";
 import {
   boardScore,
@@ -39,10 +38,13 @@ function loadMode(): Mode {
   return window.localStorage.getItem(MODE_KEY) === "3" ? 3 : 1;
 }
 
-interface Hint {
-  action: number;
-  text: string;
-  probability: number | null;
+// Off by default: taking moves back is a training aid, not how the game is played,
+// and the default should be the honest game. When on, it is limited to the current
+// turn (see turnFloor) -- you can revise a misclick, not rewind the rival.
+const UNDO_KEY = "lost-cities.undo";
+
+function loadUndoEnabled(): boolean {
+  return window.localStorage.getItem(UNDO_KEY) === "on";
 }
 
 type Selection = { handSlot: number | null; placeType: PlaceType | null };
@@ -139,8 +141,7 @@ function App() {
   const [thinking, setThinking] = useState(false);
   const [menuOpen, setMenuOpen] = useState(false);
   const [viewportWidth, setViewportWidth] = useState(() => window.innerWidth);
-  const [hint, setHint] = useState<Hint | null>(null);
-  const [hintPending, setHintPending] = useState(false);
+  const [undoEnabled, setUndoEnabled] = useState(loadUndoEnabled);
   const generation = useRef(0);
   const gameId = useRef(newGameId());
   const startedAt = useRef(new Date().toISOString());
@@ -150,13 +151,26 @@ function App() {
   const { state: match, selection } = frames[cursor];
   // The board on screen is the round in play; the match is what decides the game.
   const state = match.round;
-  const canUndo = cursor > 0;
-  const canRedo = cursor < frames.length - 1;
+  // The start of the current turn: the most recent committed move at or before the
+  // cursor (a rival move, or your own draw). Undo cannot cross it, so you can take
+  // back a card selection or placement within your turn but never rewind into the
+  // rival's move or an earlier turn.
+  const turnFloor = useMemo(() => {
+    for (let index = cursor; index > 0; index -= 1) {
+      if (frames[index].move) return index;
+    }
+    return 0;
+  }, [frames, cursor]);
+  const canUndo = undoEnabled && cursor > turnFloor;
+  const canRedo = undoEnabled && cursor < frames.length - 1;
   const latestMatch = useRef(match);
 
   useEffect(() => { publishSeed(seed); }, [seed]);
   useEffect(() => { latestMatch.current = match; }, [match]);
   useEffect(() => { window.localStorage.setItem(MODE_KEY, String(mode)); }, [mode]);
+  useEffect(() => {
+    window.localStorage.setItem(UNDO_KEY, undoEnabled ? "on" : "off");
+  }, [undoEnabled]);
   useEffect(() => {
     const saved: SavedGame = { version: 2, seed, mode, frames, cursor, resultOpen };
     window.localStorage.setItem(SAVED_GAME_KEY, JSON.stringify(saved));
@@ -258,7 +272,6 @@ function App() {
     setCursor(0);
     setSeedDraft("");
     setResultOpen(true);
-    setHint(null);
     setThinking(false);
     setMenuOpen(false);
   }
@@ -272,49 +285,12 @@ function App() {
     if (next < 0 || next >= frames.length) return;
     generation.current += 1;
     setCursor(next);
-    setHint(null);
     setThinking(false);
     setMenuOpen(false);
   }
 
-  const undo = () => moveCursor(cursor - 1);
-  const redo = () => moveCursor(cursor + 1);
-
-  /** Leave the reviewed position as the live one and let the rival play on. */
-  function resumeFromHere() {
-    setFrames((items) => items.slice(0, cursor + 1));
-    setMenuOpen(false);
-  }
-
-  /** Ask the policy driving the rival what it would do in your seat. */
-  async function requestHint() {
-    if (!policy || match.done || state.toMove !== 0 || hintPending) return;
-    const position = match;
-    setHintPending(true);
-    setMenuOpen(false);
-    try {
-      const ranked = await policy.rank(position).catch(async (error) => {
-        console.error("hint inference failed; falling back to heuristic", error);
-        return fallbackHeuristicPolicy().rank(position);
-      });
-      const [best] = ranked;
-      // The position can move on while inference runs — a hint for a stale
-      // position would point at the wrong hand slot.
-      if (best === undefined || latestMatch.current !== position) return;
-      setHint({
-        action: best.action,
-        text: describeAction(position.round, best.action),
-        probability: best.probability,
-      });
-    } catch (error) {
-      console.error("hint failed", error);
-    } finally {
-      setHintPending(false);
-    }
-  }
-
-  /** A hint answers one position; drop it as soon as anything is done or undone. */
-  useEffect(() => { setHint(null); }, [cursor, frames]);
+  const undo = () => { if (canUndo) moveCursor(cursor - 1); };
+  const redo = () => { if (canRedo) moveCursor(cursor + 1); };
 
   function chooseCard(handSlot: number) {
     if (state.toMove !== 0 || match.done) return;
@@ -374,17 +350,6 @@ function App() {
     (_, draw) => legal[encodeAction(selection.handSlot!, PLAY, draw)],
   ).some(Boolean);
 
-  const hintMove = hint === null ? null : decodeAction(hint.action);
-  const hintedCard = hintMove === null ? undefined : humanHand[hintMove.handSlot];
-  const boardHint: BoardHint | null = hintMove === null || hintedCard === undefined ? null : {
-    color: cardColor(hintedCard),
-    place: hintMove.placeType,
-    drawSource: hintMove.drawSource,
-  };
-  const hintConfidence = hint !== null && hint.probability !== null
-    ? `${Math.round(hint.probability * 100)}%`
-    : null;
-  const canHint = policy !== null && !match.done && state.toMove === 0;
 
   const outcome = scores[0] === scores[1]
     ? "DRAW"
@@ -520,6 +485,14 @@ function App() {
             </label>
             <button onClick={loadSeed} disabled={normalizeSeed(seedDraft) === ""}>DEAL THIS SEED</button>
             <span>THE SEED SHUFFLES THE DECK ONLY · THE POLICY IS DETERMINISTIC</span>
+            <label className="menu-toggle">
+              <input
+                type="checkbox"
+                checked={undoEnabled}
+                onChange={(event) => setUndoEnabled(event.target.checked)}
+              />
+              <span>ENABLE UNDO / REDO · WITHIN YOUR TURN</span>
+            </label>
             <span>{policy ? `${policy.provider.toUpperCase()} POLICY` : "LOADING POLICY"}</span>
           </div>
         )}
@@ -550,7 +523,6 @@ function App() {
           selectedPlace={selection.placeType}
           canPlay={canPlaySelected}
           canDraw={legalDraw}
-          hint={boardHint}
           cardRef={cardRef}
           onChoosePlace={choosePlace}
           onCancelPlace={cancelPlace}
@@ -560,7 +532,7 @@ function App() {
 
       <button
         type="button"
-        className={`deck-stack ${legalDraw(DRAW_DECK) ? "is-draw-target" : ""} ${hintMove?.drawSource === DRAW_DECK ? "is-hinted" : ""}`}
+        className={`deck-stack ${legalDraw(DRAW_DECK) ? "is-draw-target" : ""}`}
         disabled={!legalDraw(DRAW_DECK)}
         onClick={() => commit(DRAW_DECK)}
         aria-label={`Draw from deck, ${N_CARDS - state.drawPtr} cards left`}
@@ -572,7 +544,7 @@ function App() {
 
       <div className="prompt-row">
         <p className={`turn-prompt ${thinking ? "turn-prompt--thinking" : ""} ${reviewingRival ? "turn-prompt--review" : ""}`}>
-          {hint ? `Hint — ${hint.text}${hintConfidence ? ` (${hintConfidence})` : ""}` : status}
+          {status}
         </p>
       </div>
 
@@ -582,7 +554,6 @@ function App() {
             card={card}
             key={card}
             selected={selection.handSlot === slot}
-            hinted={hintedCard === card}
             disabled={state.toMove !== 0 || match.done}
             onClick={() => chooseCard(slot)}
             style={position === 0 ? undefined : { marginLeft: handCardMarginLeft }}
@@ -596,28 +567,16 @@ function App() {
       </section>
 
       <div className="control-stack">
-        <button
-          type="button"
-          className={`hint-button ${hint ? "is-active" : ""}`}
-          onClick={requestHint}
-          disabled={!canHint || hintPending}
-        >
-          {hintPending ? "THINKING…" : "HINT"}
-        </button>
+        {undoEnabled && (
+          <>
             <button type="button" onClick={undo} disabled={!canUndo} aria-label="Undo one action" title="Undo (←)">
               ↶ <span>UNDO</span>
             </button>
             <button type="button" onClick={redo} disabled={!canRedo} aria-label="Redo one action" title="Redo (→)">
               ↷ <span>REDO</span>
             </button>
-        <button
-          type="button"
-          className="control-stack__resume"
-          onClick={resumeFromHere}
-          disabled={!rivalSuspended}
-        >
-          PLAY FROM HERE
-        </button>
+          </>
+        )}
         <button
           type="button"
           className={`control-stack__score ${state.done && !resultOpen ? "is-available" : ""}`}

web/src/components/Board.tsx

@@ -9,20 +9,12 @@ import {
 import { cardsOnBoard } from "../game/engine";
 import { DISCARD, PLAY, type GameState, type PlaceType } from "../game/types";
 
-/** Where the hint says to put the card and where to draw from, if hinting. */
-export interface BoardHint {
-  color: number;
-  place: PlaceType;
-  drawSource: number;
-}
-
 interface BoardProps {
   state: GameState;
   selectedColor: number | null;
   selectedPlace: PlaceType | null;
   canPlay: boolean;
   canDraw: (source: number) => boolean;
-  hint: BoardHint | null;
   cardRef: (card: number) => (element: HTMLElement | null) => void;
   onChoosePlace: (place: PlaceType) => void;
   onCancelPlace: () => void;
@@ -58,7 +50,6 @@ export function Board({
   selectedPlace,
   canPlay,
   canDraw,
-  hint,
   cardRef,
   onChoosePlace,
   onCancelPlace,
@@ -75,9 +66,6 @@ export function Board({
         const drawTarget = selectedPlace !== null && canDraw(color + 1);
         const discardChosen = selectedPlace === DISCARD && selectedColor === color;
         const playChosen = selectedPlace === PLAY && selectedColor === color;
-        const hintPlay = hint?.place === PLAY && hint.color === color;
-        const hintDiscard = hint?.place === DISCARD && hint.color === color;
-        const hintDraw = hint?.drawSource === color + 1;
         return (
           <article
             className="lane"
@@ -97,7 +85,7 @@ export function Board({
 
             <button
               type="button"
-              className={`lane__discard ${discardTarget ? "is-target" : ""} ${drawTarget ? "is-draw-target" : ""} ${discardChosen ? "is-chosen" : ""} ${hintDiscard || hintDraw ? "is-hinted" : ""}`}
+              className={`lane__discard ${discardTarget ? "is-target" : ""} ${drawTarget ? "is-draw-target" : ""} ${discardChosen ? "is-chosen" : ""}`}
               onClick={() => drawTarget ? onDraw(color + 1) : discardChosen ? onCancelPlace() : discardTarget ? onChoosePlace(DISCARD) : undefined}
               disabled={!discardTarget && !drawTarget && !discardChosen}
               aria-label={discardChosen ? `Cancel discarding to ${name} pile` : `${name} discard pile`}
@@ -113,7 +101,7 @@ export function Board({
 
             <button
               type="button"
-              className={`lane__zone lane__zone--mine ${playTarget ? "is-target" : ""} ${playChosen ? "is-chosen" : ""} ${hintPlay ? "is-hinted" : ""}`}
+              className={`lane__zone lane__zone--mine ${playTarget ? "is-target" : ""} ${playChosen ? "is-chosen" : ""}`}
               onClick={() => playChosen ? onCancelPlace() : playTarget ? onChoosePlace(PLAY) : undefined}
               disabled={!playTarget && !playChosen}
               aria-label={playChosen ? `Cancel playing to your ${name} expedition` : `Your ${name} expedition`}

web/src/components/Card.tsx

@@ -14,7 +14,6 @@ interface CardProps {
    *  hand row is only as tall as a card back, so a full card would burst it. */
   mini?: boolean;
   selected?: boolean;
-  hinted?: boolean;
   disabled?: boolean;
   onClick?: () => void;
   style?: React.CSSProperties;
@@ -26,7 +25,6 @@ export function Card({
   compact = false,
   mini = false,
   selected = false,
-  hinted = false,
   disabled = false,
   onClick,
   style: styleOverride,
@@ -35,7 +33,7 @@ export function Card({
   const color = cardColor(card);
   const value = cardValue(card);
   const handshake = isHandshake(card);
-  const className = `card ${compact ? "card--compact" : ""} ${mini ? "card--mini" : ""} ${selected ? "card--selected" : ""} ${hinted ? "card--hinted" : ""}`;
+  const className = `card ${compact ? "card--compact" : ""} ${mini ? "card--mini" : ""} ${selected ? "card--selected" : ""}`;
   const style = { "--card-color": COLOR_HEX[color], ...styleOverride } as React.CSSProperties;
   const content = (
     <>

web/src/styles.css

@@ -333,28 +333,10 @@ button.lane__discard:disabled { opacity: 1; }
   pointer-events: none;
 }
 
-/* The hinted card, its destination, and its draw source. */
-.card--hinted { box-shadow: 0 0 0 3px var(--gold), 0 0 26px rgba(201, 163, 75, 0.35); }
-.lane__zone.is-hinted,
-.lane__discard.is-hinted,
-.deck-stack.is-hinted { animation: target-pulse 1.6s ease-in-out infinite; }
-.lane__zone.is-hinted .lane__ghost,
-.lane__discard.is-hinted .lane__ghost {
-  border-color: var(--gold);
-  border-style: dashed;
-  opacity: 0.9;
-}
-.lane__zone.is-hinted .card,
-.lane__discard.is-hinted .card,
-.deck-stack.is-hinted .card { box-shadow: 0 0 0 2px var(--gold), 0 0 26px rgba(201, 163, 75, 0.3); }
-
 @media (prefers-reduced-motion: reduce) {
   .lane__zone.is-target,
   .lane__discard.is-target,
   .lane__discard.is-draw-target,
-  .lane__zone.is-hinted,
-  .lane__discard.is-hinted,
-  .deck-stack.is-hinted,
   .deck-stack.is-draw-target { animation: none; }
 }
 
@@ -541,19 +523,6 @@ button.card:disabled { cursor: default; }
 .turn-prompt--thinking { color: #c6b887; }
 .turn-prompt--review { color: #9fb4c8; }
 
-.hint-button {
-  height: 32px;
-  padding: 0 14px;
-  border: 1px solid var(--gold-dim);
-  border-radius: 9px;
-  background: rgba(7, 13, 12, 0.9);
-  font: 700 9px Arial, sans-serif;
-  letter-spacing: 0.16em;
-  cursor: pointer;
-}
-.hint-button:hover:not(:disabled) { border-color: var(--gold); }
-.hint-button:disabled { opacity: 0.35; cursor: default; }
-.hint-button.is-active { border-color: var(--gold); color: var(--gold); }
 
 .human-hand {
   position: absolute;
@@ -682,12 +651,6 @@ button.card:disabled { cursor: default; }
 .control-stack button span { font: 700 9px Arial, sans-serif; letter-spacing: 0.14em; }
 .control-stack button:hover:not(:disabled) { border-color: var(--gold); }
 .control-stack button:disabled { opacity: 0.3; cursor: default; }
-.control-stack__resume {
-  border-color: var(--gold) !important;
-  color: var(--gold);
-  font: 700 9px Arial, sans-serif;
-  letter-spacing: 0.14em;
-}
 .control-stack__score { visibility: hidden; }
 .control-stack__score.is-available { visibility: visible; }
 
@@ -801,3 +764,15 @@ button.card:disabled { cursor: default; }
   color: #f0d9a6;
   font-weight: 700;
 }
+
+/* The undo/redo settings switch. Off by default: taking moves back is a training
+   aid, and the honest game is the sensible default. */
+.menu-toggle {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 6px 4px;
+  cursor: pointer;
+}
+.menu-toggle input { width: 15px; height: 15px; accent-color: var(--gold); cursor: pointer; }
+.menu-toggle span { padding: 0; color: #9a9d97; }