Phase 3: Check my work, follow-ups and turn-into-deck

Check my work (third homework mode)
- One model call with its own system prompt marks the student's own
  attempt: verdict, what's right, each issue with why + fix, and the
  corrected version that keeps everything the student got right.
  Unasked-for extras are never errors. The attempt is typed/pasted
  (photos of handwriting are documented as unsupported) and stored in
  the record so Redo re-checks the same work.
- Server: mode "check" + solution on POST /api/homework (zod, 400
  server.needSolution without one) and the same NDJSON stream; new
  checkHomework() pipeline with repair-once validation.

Follow-ups
- New POST /api/homework/refine (plain JSON, RATE_LIMIT_REFINE, zod,
  auth before body): shorter / more detail / explain, plain text back,
  language preserved.
- Shorter + More detail + Original rewrite the finished answer and the
  corrected version in place (FollowUpBar); every guide step has
  Explain step N differently; failed calls say so without losing text.

Turn into a study deck
- Any result hands its content (answer, corrected version or assembled
  guide) to New deck through a one-shot sessionStorage seed with the
  options step pre-filled.

UI
- Phone step 2 gains the third card: tapping it reveals the solution
  field + submit; desktop has three cards and the solution field shows
  with the mode. Homework history labels and share/card previews cover
  the new mode.

Verified: new phase-3 suite 20/20 against a stub Ollama (check payload,
missing-solution 400, refine validation, phone + desktop check flows,
shorter follow-up with restore, guide explain, deck hand-off) plus
regression 74/74, mobile 52/52, declutter 116/116, wizard 80/80,
animation 8/8, native 35/35, phase1 38/38, phase2 43/43, i18n 25/25.
Key parity 734/734. Lint + build clean. SW freezmo-v27.

components/homework/FollowUpBar.tsx

@@ -0,0 +1,76 @@
+"use client";
+
+import { useState } from "react";
+
+import { Button } from "@/components/ui";
+import { refineHomework } from "@/lib/client-api";
+import { useI18n } from "@/lib/i18n";
+
+/**
+ * Follow-up actions for one finished piece of homework: shorter, more detail,
+ * or back to the original. Used on the make result and the corrected version
+ * of a check.
+ */
+export function FollowUpBar({
+  text,
+  context,
+  onReplace,
+  onRestore,
+  canRestore,
+}: {
+  text: string;
+  context?: string;
+  onReplace: (next: string) => void;
+  onRestore?: () => void;
+  canRestore?: boolean;
+}) {
+  const { t } = useI18n();
+  const [busy, setBusy] = useState<"shorter" | "more" | null>(null);
+  const [failed, setFailed] = useState(false);
+
+  const run = async (instruction: "shorter" | "more") => {
+    if (busy) return;
+    setBusy(instruction);
+    setFailed(false);
+    try {
+      const next = await refineHomework({ instruction, text, context });
+      onReplace(next);
+    } catch {
+      setFailed(true);
+    } finally {
+      setBusy(null);
+    }
+  };
+
+  return (
+    <div className="flex flex-wrap items-center gap-2">
+      <Button
+        size="sm"
+        variant="secondary"
+        className="touch-target"
+        loading={busy === "shorter"}
+        disabled={Boolean(busy)}
+        onClick={() => void run("shorter")}
+      >
+        {t("homework.followup.shorter")}
+      </Button>
+      <Button
+        size="sm"
+        variant="secondary"
+        className="touch-target"
+        loading={busy === "more"}
+        disabled={Boolean(busy)}
+        onClick={() => void run("more")}
+      >
+        {t("homework.followup.more")}
+      </Button>
+      {busy ? <span className="text-[12px] text-[var(--text-subtle)]">{t("homework.followup.working")}</span> : null}
+      {canRestore && onRestore ? (
+        <Button size="sm" variant="ghost" className="touch-target" disabled={Boolean(busy)} onClick={onRestore}>
+          {t("homework.followup.restore")}
+        </Button>
+      ) : null}
+      {failed ? <span className="text-[12px] font-medium text-rose-600 dark:text-rose-300">{t("homework.followup.failed")}</span> : null}
+    </div>
+  );
+}

components/homework/HomeworkCheckResult.tsx

@@ -0,0 +1,113 @@
+"use client";
+
+import { useState } from "react";
+
+import { Button } from "@/components/ui";
+import { useI18n } from "@/lib/i18n";
+import type { HomeworkCheckRecord } from "@/lib/schemas";
+
+import { CopyButton } from "./CopyButton";
+import { FollowUpBar } from "./FollowUpBar";
+
+/** Mode 3 result: verdict, what's right, what needs fixing, corrected version. */
+export function HomeworkCheckResult({
+  record,
+  onAgain,
+  onNew,
+  onToDeck,
+  againLoading,
+}: {
+  record: HomeworkCheckRecord;
+  onAgain: () => void;
+  onNew: () => void;
+  onToDeck: () => void;
+  againLoading: boolean;
+}) {
+  const { t } = useI18n();
+  const [corrected, setCorrected] = useState(record.corrected);
+
+  return (
+    <div className="space-y-5">
+      <header className="space-y-1">
+        <p className="text-[11px] font-semibold uppercase tracking-wider text-[var(--text-subtle)]">
+          {t("homework.check.title")}
+        </p>
+        <h1 className="text-[22px] font-semibold leading-tight tracking-[-0.02em] text-[var(--text)] text-balance">
+          {record.title}
+        </h1>
+      </header>
+
+      <section className="card space-y-1.5 p-4">
+        <p className="text-[11px] font-semibold uppercase tracking-wide text-[var(--text-subtle)]">
+          {t("homework.check.verdict")}
+        </p>
+        <p className="text-[15px] leading-relaxed text-[var(--text)]">{record.verdict}</p>
+      </section>
+
+      {record.correct.length > 0 ? (
+        <section className="rounded-2xl border border-emerald-200/80 bg-emerald-50/90 p-4 dark:border-emerald-400/30 dark:bg-emerald-500/10">
+          <p className="text-[11px] font-semibold uppercase tracking-wide text-emerald-800 dark:text-emerald-200">
+            {t("homework.check.correct")}
+          </p>
+          <ul className="mt-2 list-inside list-disc space-y-1 text-[14px] leading-relaxed text-emerald-900 dark:text-emerald-100">
+            {record.correct.map((item, index) => (
+              <li key={index}>{item}</li>
+            ))}
+          </ul>
+        </section>
+      ) : null}
+
+      {record.wrong.length > 0 ? (
+        <section className="rounded-2xl border border-rose-200/80 bg-rose-50/90 p-4 dark:border-rose-400/30 dark:bg-rose-500/10">
+          <p className="text-[11px] font-semibold uppercase tracking-wide text-rose-800 dark:text-rose-200">
+            {t("homework.check.wrong")}
+          </p>
+          <ul className="mt-2 space-y-3">
+            {record.wrong.map((entry, index) => (
+              <li key={index} className="space-y-0.5 text-[14px] leading-relaxed text-rose-900 dark:text-rose-100">
+                <p className="font-semibold">{entry.issue}</p>
+                <p>{entry.why}</p>
+                {entry.fix ? (
+                  <p>
+                    <span className="font-bold">{t("homework.check.fix")}: </span>
+                    {entry.fix}
+                  </p>
+                ) : null}
+              </li>
+            ))}
+          </ul>
+        </section>
+      ) : null}
+
+      <article className="card space-y-3 p-4 sm:p-5">
+        <p className="text-[11px] font-semibold uppercase tracking-wide text-[var(--text-subtle)]">
+          {t("homework.check.corrected")}
+        </p>
+        <p className="whitespace-pre-wrap break-words text-[15px] leading-relaxed text-[var(--text)]">{corrected}</p>
+        <div className="flex flex-wrap items-center gap-2">
+          <CopyButton text={corrected} />
+          <FollowUpBar
+            text={corrected}
+            context={record.sourceText}
+            onReplace={setCorrected}
+            onRestore={() => setCorrected(record.corrected)}
+            canRestore={corrected !== record.corrected}
+          />
+        </div>
+      </article>
+
+      <div className="flex flex-wrap items-start gap-2">
+        <Button variant="secondary" className="touch-target" onClick={onAgain} loading={againLoading}>
+          {t("homework.followup.redo")}
+        </Button>
+        <Button variant="secondary" className="touch-target" onClick={onToDeck}>
+          {t("homework.toDeck")}
+        </Button>
+        <Button variant="ghost" className="touch-target" onClick={onNew}>
+          {t("homework.result.new")}
+        </Button>
+      </div>
+      <p className="text-[11.5px] text-[var(--text-subtle)]">{t("homework.toDeckNote")}</p>
+    </div>
+  );
+}

components/homework/HomeworkGuide.tsx

@@ -11,6 +11,7 @@ import { assembleSolution } from "@/lib/homework";
 import { useI18n } from "@/lib/i18n";
 import type { HomeworkGuideRecord, HomeworkStep } from "@/lib/schemas";
 import { useWakeLock } from "@/lib/use-wake-lock";
+import { refineHomework } from "@/lib/client-api";
 
 import { CopyButton } from "./CopyButton";
 
@@ -25,12 +26,14 @@ export function HomeworkGuide({
   onClose,
   onAgain,
   onNew,
+  onToDeck,
   againLoading,
 }: {
   record: HomeworkGuideRecord;
   onClose: () => void;
   onAgain: () => void;
   onNew: () => void;
+  onToDeck: () => void;
   againLoading: boolean;
 }) {
   const { t } = useI18n();
@@ -40,8 +43,30 @@ export function HomeworkGuide({
   const slideCount = steps.length + 1; // + the solution slide
   const [index, setIndex] = useState(0);
   const [revealed, setRevealed] = useState<Record<number, number>>({});
+  /** "Explain this step differently" overrides, per step index. */
+  const [explained, setExplained] = useState<Record<number, string>>({});
+  const [explaining, setExplaining] = useState<number | null>(null);
+  const [explainFailed, setExplainFailed] = useState<number | null>(null);
   const scrollRef = useRef<HTMLDivElement>(null);
 
+  const explainStep = async (stepIndex: number) => {
+    if (explaining !== null) return;
+    setExplaining(stepIndex);
+    setExplainFailed(null);
+    try {
+      const next = await refineHomework({
+        instruction: "explain",
+        text: steps[stepIndex].explanation,
+        context: record.sourceText,
+      });
+      setExplained((current) => ({ ...current, [stepIndex]: next }));
+    } catch {
+      setExplainFailed(stepIndex);
+    } finally {
+      setExplaining(null);
+    }
+  };
+
   const goTo = useCallback(
     (target: number) => {
       const container = scrollRef.current;
@@ -164,8 +189,25 @@ export function HomeworkGuide({
               <PromptCard>
                 <QuestionText>{step.title}</QuestionText>
                 <p className="mt-2 text-[15px] leading-relaxed text-frost-700 dark:text-frost-200">
-                  {step.explanation}
+                  {explained[stepIndex] ?? step.explanation}
                 </p>
+                <div className="mt-2 flex flex-wrap items-center gap-2">
+                  <Button
+                    size="sm"
+                    variant="ghost"
+                    className="touch-target"
+                    loading={explaining === stepIndex}
+                    disabled={explaining !== null}
+                    onClick={() => void explainStep(stepIndex)}
+                  >
+                    {t("homework.followup.step", { n: stepIndex + 1 })}
+                  </Button>
+                  {explainFailed === stepIndex ? (
+                    <span className="text-[12px] font-medium text-rose-600 dark:text-rose-300">
+                      {t("homework.followup.failed")}
+                    </span>
+                  ) : null}
+                </div>
               </PromptCard>
 
               {/* progressive hints */}
@@ -242,12 +284,16 @@ export function HomeworkGuide({
             <div className="flex flex-wrap items-start gap-2">
               <CopyButton text={solution} />
               <Button variant="secondary" className="touch-target" onClick={onAgain} loading={againLoading}>
-                {t("homework.result.again")}
+                {t("homework.followup.redo")}
+              </Button>
+              <Button variant="secondary" className="touch-target" onClick={onToDeck}>
+                {t("homework.toDeck")}
               </Button>
               <Button variant="ghost" className="touch-target" onClick={onNew}>
                 {t("homework.result.new")}
               </Button>
             </div>
+            <p className="text-[11.5px] text-[var(--text-subtle)]">{t("homework.toDeckNote")}</p>
           </div>
         </section>
       </div>

components/homework/HomeworkInput.tsx

@@ -4,7 +4,7 @@ import { motion, useReducedMotion } from "framer-motion";
 import { useRouter } from "next/navigation";
 import { useEffect, useRef, useState } from "react";
 
-import { CameraIcon, FolderIcon, PlayIcon, PlusIcon, SparklesIcon } from "@/components/icons";
+import { CameraIcon, CheckCircleIcon, FolderIcon, PlayIcon, PlusIcon, SparklesIcon } from "@/components/icons";
 import { Button } from "@/components/ui";
 import { WizardActionBar } from "@/components/WizardActionBar";
 import {
@@ -47,6 +47,7 @@ function describeExtraction(
 const MODES: Array<{ id: HomeworkMode; icon: React.ReactNode; titleKey: string; subtitleKey: string }> = [
   { id: "make", icon: <SparklesIcon className="size-5" />, titleKey: "homework.mode.make.title", subtitleKey: "homework.mode.make.subtitle" },
   { id: "guide", icon: <PlayIcon className="size-5" />, titleKey: "homework.mode.guide.title", subtitleKey: "homework.mode.guide.subtitle" },
+  { id: "check", icon: <CheckCircleIcon className="size-5" />, titleKey: "homework.mode.check", subtitleKey: "homework.mode.checkDesc" },
 ];
 
 export function HomeworkInput({
@@ -54,6 +55,8 @@ export function HomeworkInput({
   onModeChange,
   text,
   onTextChange,
+  solution,
+  onSolutionChange,
   intake,
   onSubmit,
   error,
@@ -65,6 +68,9 @@ export function HomeworkInput({
   onModeChange: (mode: HomeworkMode) => void;
   text: string;
   onTextChange: (text: string) => void;
+  /** Mode "check": the student's own attempt. */
+  solution: string;
+  onSolutionChange: (solution: string) => void;
   intake: ReturnType<typeof useNotesIntake>;
   /** `modeOverride` lets the phone mode cards start the run they tapped. */
   onSubmit: (modeOverride?: HomeworkMode) => void;
@@ -80,6 +86,8 @@ export function HomeworkInput({
   const [step, setStep] = useState(1);
   const [stepDir, setStepDir] = useState<1 | -1>(1);
   const [pasteOpen, setPasteOpen] = useState(false);
+  /** Phones: the check card reveals the solution field instead of starting. */
+  const [checkOpen, setCheckOpen] = useState(false);
   const isPhone = useIsPhone();
   const reduceMotion = useReducedMotion();
   const online = useOnline();
@@ -176,6 +184,29 @@ export function HomeworkInput({
     </div>
   ) : null;
 
+  /* Shared solution field: typed/pasted only (documented in the note). */
+  const solutionField = (
+    <div className="space-y-1.5">
+      <label className="text-[12px] font-semibold text-[var(--text)]" htmlFor="homework-solution">
+        {t("homework.solution.label")}
+      </label>
+      <textarea
+        id="homework-solution"
+        value={solution}
+        onChange={(event) => onSolutionChange(event.target.value)}
+        rows={5}
+        placeholder={t("homework.solution.placeholder")}
+        inputMode="text"
+        enterKeyHint="done"
+        autoComplete="off"
+        autoCapitalize="sentences"
+        spellCheck
+        className="w-full resize-y rounded-2xl border border-white/60 bg-white/55 px-4 py-3 text-sm text-frost-950 outline-none backdrop-blur-xl transition placeholder:text-frost-400 focus:border-accent-400 dark:border-white/12 dark:bg-white/[0.07] dark:text-frost-50"
+      />
+      <p className="text-[11px] leading-snug text-[var(--text-subtle)]">{t("homework.solution.note")}</p>
+    </div>
+  );
+
   /* Shared mode card: desktop toggles the selection, the phone flow starts it. */
   const modeCard = (option: (typeof MODES)[number], onPick: () => void) => {
     const selected = mode === option.id;
@@ -479,12 +510,35 @@ export function HomeworkInput({
                 {MODES.map((option) =>
                   modeCard(option, () => {
                     if (!canSubmit || !online) return;
+                    if (option.id === "check") {
+                      // Needs the solution first: reveal the field instead of
+                      // starting the run.
+                      onModeChange("check");
+                      setCheckOpen(true);
+                      return;
+                    }
                     clearWizardDraft("homework");
                     onModeChange(option.id);
                     onSubmit(option.id);
                   }),
                 )}
               </div>
+              {checkOpen ? (
+                <div className="space-y-3">
+                  {solutionField}
+                  <Button
+                    size="lg"
+                    className="touch-target w-full"
+                    disabled={!canSubmit || !solution.trim()}
+                    onClick={() => {
+                      clearWizardDraft("homework");
+                      onSubmit("check");
+                    }}
+                  >
+                    {t("homework.mode.check")}
+                  </Button>
+                </div>
+              ) : null}
               <p className="text-center text-[12px] text-[var(--text-subtle)]">
                 {online ? t("homework.phone.startHint") : t("offline.generate")}
               </p>
@@ -704,16 +758,23 @@ export function HomeworkInput({
       {/* ------------------------------------------------------- mode */}
       <section className="space-y-3">
         <h2 className="text-[15px] font-semibold tracking-[-0.01em] text-[var(--text)]">{t("homework.mode.title")}</h2>
-        <div className="grid gap-3 sm:grid-cols-2">
+        <div className="grid gap-3 sm:grid-cols-3">
           {MODES.map((option) => modeCard(option, () => onModeChange(option.id)))}
         </div>
+        {mode === "check" ? solutionField : null}
       </section>
 
       {/* -------------------------------------------------------- CTA */}
       <div className="space-y-2">
-        <Button size="lg" className="touch-target w-full" onClick={() => onSubmit()} disabled={!canSubmit} loading={intake.busy}>
+        <Button
+          size="lg"
+          className="touch-target w-full"
+          onClick={() => onSubmit()}
+          disabled={!canSubmit || (mode === "check" && !solution.trim())}
+          loading={intake.busy}
+        >
           <SparklesIcon className="size-5" />
-          {mode === "make" ? t("homework.start.make") : t("homework.start.guide")}
+          {mode === "make" ? t("homework.start.make") : mode === "guide" ? t("homework.start.guide") : t("homework.mode.check")}
         </Button>
         <p className="text-center text-[12px] text-[var(--text-subtle)]">
           {canSubmit ? t("homework.source.ready") : t("homework.source.need")}

components/homework/HomeworkResult.tsx

@@ -1,25 +1,31 @@
 "use client";
 
+import { useState } from "react";
+
 import { Button } from "@/components/ui";
 import { useI18n } from "@/lib/i18n";
 import type { HomeworkMakeRecord } from "@/lib/schemas";
 import { shareHomework } from "@/lib/share";
 
 import { CopyButton } from "./CopyButton";
+import { FollowUpBar } from "./FollowUpBar";
 
 /** Mode 1 result: the finished homework, nothing else. */
 export function HomeworkResult({
   record,
   onAgain,
   onNew,
+  onToDeck,
   againLoading,
 }: {
   record: HomeworkMakeRecord;
   onAgain: () => void;
   onNew: () => void;
+  onToDeck: () => void;
   againLoading: boolean;
 }) {
   const { t } = useI18n();
+  const [answer, setAnswer] = useState(record.answer);
 
   return (
     <div className="space-y-5">
@@ -32,24 +38,33 @@ export function HomeworkResult({
         </h1>
       </header>
 
-      <article className="card p-4 sm:p-5">
-        <p className="whitespace-pre-wrap break-words text-[15px] leading-relaxed text-[var(--text)]">
-          {record.answer}
-        </p>
+      <article className="card space-y-3 p-4 sm:p-5">
+        <p className="whitespace-pre-wrap break-words text-[15px] leading-relaxed text-[var(--text)]">{answer}</p>
+        <FollowUpBar
+          text={answer}
+          context={record.sourceText}
+          onReplace={setAnswer}
+          onRestore={() => setAnswer(record.answer)}
+          canRestore={answer !== record.answer}
+        />
       </article>
 
       <div className="flex flex-wrap items-start gap-2">
-        <CopyButton text={record.answer} />
-        <Button variant="secondary" className="touch-target" onClick={() => void shareHomework(record)}>
+        <CopyButton text={answer} />
+        <Button variant="secondary" className="touch-target" onClick={() => void shareHomework({ ...record, answer })}>
           {t("deck.share")}
         </Button>
         <Button variant="secondary" className="touch-target" onClick={onAgain} loading={againLoading}>
-          {t("homework.result.again")}
+          {t("homework.followup.redo")}
+        </Button>
+        <Button variant="secondary" className="touch-target" onClick={onToDeck}>
+          {t("homework.toDeck")}
         </Button>
         <Button variant="ghost" className="touch-target" onClick={onNew}>
           {t("homework.result.new")}
         </Button>
       </div>
+      <p className="text-[11.5px] text-[var(--text-subtle)]">{t("homework.toDeckNote")}</p>
     </div>
   );
 }

components/homework/HomeworkScreen.tsx

@@ -1,10 +1,13 @@
 "use client";
 
 import { useCallback, useEffect, useMemo, useRef, useState, useSyncExternalStore } from "react";
+import { useRouter } from "next/navigation";
 
 import { documentsToText } from "@/lib/documents";
 import { ApiError, generateHomework, type HomeworkProgress } from "@/lib/client-api";
+import { setDeckSeed } from "@/lib/deck-seed";
 import {
+  assembleSolution,
   deleteHomework,
   getHomework,
   homeworkStore,
@@ -18,6 +21,7 @@ import type { HomeworkMode, HomeworkRecord } from "@/lib/schemas";
 import { useNotesIntake } from "@/lib/use-notes-intake";
 import { clearWizardDraft } from "@/lib/wizard-draft";
 
+import { HomeworkCheckResult } from "./HomeworkCheckResult";
 import { HomeworkGuide } from "./HomeworkGuide";
 import { HomeworkInput } from "./HomeworkInput";
 import { HomeworkLoading } from "./HomeworkLoading";
@@ -32,6 +36,7 @@ type View = { kind: "start" } | { kind: "loading" } | { kind: "record"; record:
 /** The /homework screen: give it an assignment, pick a mode, get a result. */
 export function HomeworkScreen({ initialRecordId }: { initialRecordId?: string }) {
   const { t } = useI18n();
+  const router = useRouter();
   const records = useSyncExternalStore(
     homeworkStore.subscribe,
     homeworkStore.getSnapshot,
@@ -45,6 +50,8 @@ export function HomeworkScreen({ initialRecordId }: { initialRecordId?: string }
 
   const [mode, setMode] = useState<HomeworkMode>("make");
   const [text, setText] = useState("");
+  /** Mode "check": the student's own attempt at the assignment. */
+  const [solution, setSolution] = useState("");
   const [view, setView] = useState<View>({ kind: "start" });
   const [progress, setProgress] = useState<HomeworkProgress>({ stage: "vision", message: "" });
   const [error, setError] = useState<{ message: string; kind?: string } | null>(null);
@@ -68,11 +75,16 @@ export function HomeworkScreen({ initialRecordId }: { initialRecordId?: string }
       ...intake.images.map((image) => image.dataUrl),
       ...documentImages.map((image) => image.dataUrl),
     ].slice(0, MAX_IMAGES_TO_SEND);
-    return { mode: modeValue, images, text: mergedText };
+    return {
+      mode: modeValue,
+      images,
+      text: mergedText,
+      solution: modeValue === "check" ? solution.trim() : undefined,
+    };
   };
 
   const run = useCallback(
-    async (input: { mode: HomeworkMode; images: string[]; text: string; recordId?: string }) => {
+    async (input: { mode: HomeworkMode; images: string[]; text: string; solution?: string; recordId?: string }) => {
       setError(null);
       setView({ kind: "loading" });
       const vision = input.images.length > 0;
@@ -82,7 +94,9 @@ export function HomeworkScreen({ initialRecordId }: { initialRecordId?: string }
           ? t("homework.loading.reading")
           : input.mode === "make"
             ? t("homework.loading.writing")
-            : t("homework.loading.planning"),
+            : input.mode === "check"
+              ? t("homework.loading.checking")
+              : t("homework.loading.planning"),
       });
 
       const controller = new AbortController();
@@ -94,12 +108,13 @@ export function HomeworkScreen({ initialRecordId }: { initialRecordId?: string }
             mode: input.mode,
             images: input.images.length > 0 ? input.images : undefined,
             text: input.text || undefined,
+            solution: input.solution,
           },
           { onProgress: setProgress, signal: controller.signal },
         );
 
         // The server hands back the assignment as text (the transcription when
-        // photos were used), so “Make it again” works without the files.
+        // photos were used), so “Redo” works without the files.
         const sourceText = homework.sourceText ?? input.text;
         const result: NewHomeworkResult =
           homework.mode === "make"
@@ -110,13 +125,25 @@ export function HomeworkScreen({ initialRecordId }: { initialRecordId?: string }
                 sourceText,
                 answer: homework.answer,
               }
-            : {
-                mode: "guide",
-                title: homework.title,
-                language: homework.language,
-                sourceText,
-                steps: homework.steps,
-              };
+            : homework.mode === "check"
+              ? {
+                  mode: "check",
+                  title: homework.title,
+                  language: homework.language,
+                  sourceText,
+                  verdict: homework.verdict,
+                  correct: homework.correct,
+                  wrong: homework.wrong,
+                  corrected: homework.corrected,
+                  attempt: input.solution,
+                }
+              : {
+                  mode: "guide",
+                  title: homework.title,
+                  language: homework.language,
+                  sourceText,
+                  steps: homework.steps,
+                };
 
         const record = input.recordId ? updateHomework(input.recordId, result) : saveHomework(result);
         if (!record) throw new ApiError(t("homework.error.body"), "bad_response");
@@ -141,19 +168,43 @@ export function HomeworkScreen({ initialRecordId }: { initialRecordId?: string }
 
   /** `modeOverride` lets the phone flow start straight from a tapped mode card. */
   const submit = (modeOverride?: HomeworkMode) => {
-    const payload = buildPayload(modeOverride ?? mode);
+    const target = modeOverride ?? mode;
+    if (target === "check" && !solution.trim()) {
+      setError({ message: t("homework.solution.required") });
+      return;
+    }
+    const payload = buildPayload(target);
     void run(payload);
   };
 
   /** Re-run from the stored assignment text (files were never stored). */
   const again = (record: HomeworkRecord) => {
     setAgainLoading(true);
-    void run({ mode: record.mode, images: [], text: record.sourceText, recordId: record.id });
+    void run({
+      mode: record.mode,
+      images: [],
+      text: record.sourceText,
+      solution: record.mode === "check" ? record.attempt : undefined,
+      recordId: record.id,
+    });
+  };
+
+  /** Hand the finished content to the New deck flow with the options pre-filled. */
+  const turnIntoDeck = (record: HomeworkRecord) => {
+    const content =
+      record.mode === "make"
+        ? record.answer
+        : record.mode === "check"
+          ? record.corrected
+          : assembleSolution(record);
+    setDeckSeed({ text: content, difficulty: "medium", count: 10 });
+    router.push("/create");
   };
 
   const newAssignment = () => {
     intake.clear();
     setText("");
+    setSolution("");
     setError(null);
     clearWizardDraft("homework");
     setView({ kind: "start" });
@@ -164,19 +215,35 @@ export function HomeworkScreen({ initialRecordId }: { initialRecordId?: string }
   }
 
   if (view.kind === "record") {
-    return view.record.mode === "make" ? (
-      <HomeworkResult
-        record={view.record}
-        onAgain={() => again(view.record)}
-        onNew={newAssignment}
-        againLoading={againLoading}
-      />
-    ) : (
+    if (view.record.mode === "make") {
+      return (
+        <HomeworkResult
+          record={view.record}
+          onAgain={() => again(view.record)}
+          onNew={newAssignment}
+          onToDeck={() => turnIntoDeck(view.record)}
+          againLoading={againLoading}
+        />
+      );
+    }
+    if (view.record.mode === "check") {
+      return (
+        <HomeworkCheckResult
+          record={view.record}
+          onAgain={() => again(view.record)}
+          onNew={newAssignment}
+          onToDeck={() => turnIntoDeck(view.record)}
+          againLoading={againLoading}
+        />
+      );
+    }
+    return (
       <HomeworkGuide
         record={view.record}
         onClose={() => setView({ kind: "start" })}
         onAgain={() => again(view.record)}
         onNew={newAssignment}
+        onToDeck={() => turnIntoDeck(view.record)}
         againLoading={againLoading}
       />
     );
@@ -188,6 +255,8 @@ export function HomeworkScreen({ initialRecordId }: { initialRecordId?: string }
       onModeChange={setMode}
       text={text}
       onTextChange={setText}
+      solution={solution}
+      onSolutionChange={setSolution}
       intake={intake}
       onSubmit={submit}
       error={error}