feat: sync savings chat history with convex

backlog/tasks/task-9 - Add-Convex-synced-savings-chat-history.md

@@ -0,0 +1,72 @@
+---
+id: TASK-9
+title: Add Convex-synced savings chat history
+status: Done
+assignee: []
+created_date: '2026-06-16 07:58'
+updated_date: '2026-06-16 08:23'
+labels: []
+dependencies: []
+priority: high
+ordinal: 9000
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+Persist savings chat sessions and messages in Convex per authenticated user so chat history syncs across devices, with automatic one-time import of existing localStorage chats.
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+<!-- AC:BEGIN -->
+- [x] #1 Chat sessions and messages are stored in Convex per authenticated user and synchronize across devices
+- [x] #2 Existing localStorage savings chats are imported once, deduplicated by legacy local id, and old local data is not deleted
+- [x] #3 Sending a chat message stores both user and assistant messages, including assistant tool traces
+- [x] #4 Deleting a chat hides it account-wide and unauthorized users cannot read or mutate another user's chats
+- [x] #5 Focused Convex tests, focused ESLint, and build verification are run and recorded
+<!-- AC:END -->
+
+## Implementation Plan
+
+<!-- SECTION:PLAN:BEGIN -->
+1. Add failing Convex tests for user-scoped chat history, legacy import, sendMessage persistence, and deletion
+2. Add chatSessions/chatMessages schema tables
+3. Implement savingsChatHistory queries and mutations
+4. Refactor savingsChat AI generation helper and add sendMessage action
+5. Move SavingsChatPage to Convex-backed state and automatic legacy import
+6. Run focused tests, focused lint, build, and record verification notes
+<!-- SECTION:PLAN:END -->
+
+## Implementation Notes
+
+<!-- SECTION:NOTES:BEGIN -->
+Implementation completed on branch codex/convex-chat-history-sync.
+
+Verification:
+- RED verified first: npx vitest convex/savingsChat.test.ts --run failed with 3 missing chat-history/sendMessage tests.
+- PASS npx vitest convex/savingsChat.test.ts --run (25 tests).
+- PASS npx eslint convex/schema.ts convex/savingsChat.ts convex/savingsChatHistory.ts convex/savingsChat.test.ts src/pages/SavingsChatPage.tsx src/components/chat/ChatHistory.tsx.
+- PASS npm run build (Vite chunk-size warning remains).
+- FULL LINT npm run lint still fails on pre-existing unrelated files: convex/bank/comdirectProvider.ts, convex/bank/config.ts, src/components/import/TanAwaitDialog.tsx, layout/ui fast-refresh exports, src/main.tsx, src/pages/SettingsPage.tsx, plus existing React Compiler warnings. No changed feature file appears in the full-lint error list.
+
+Notes:
+- Ran npx convex codegen; first sandboxed attempt failed on DNS/fetch to Sentry, rerun outside sandbox succeeded and updated convex/_generated/api.d.ts.
+- Backlog task remains In Progress pending explicit user confirmation after manual testing.
+
+Review follow-up:
+- Addressed code-review finding: legacy import marker is now scoped by current Convex user id instead of only browser-global.
+- Addressed code-review finding: sendMessage now persists an assistant failure message if AI generation fails after saving the user message.
+- Added regression coverage for unauthorized listMessages, unauthorized sendMessage, and failed-generation persistence.
+
+Final verification after review fixes:
+- PASS npx vitest convex/savingsChat.test.ts --run (26 tests).
+- PASS npx eslint convex/schema.ts convex/savingsChat.ts convex/savingsChatHistory.ts convex/savingsChat.test.ts src/pages/SavingsChatPage.tsx src/components/chat/ChatHistory.tsx.
+- PASS npm run build (Vite chunk-size warning remains).
+- FULL LINT npm run lint still fails only on pre-existing unrelated files and generated-file warnings; no changed feature file is in the full-lint error list.
+<!-- SECTION:NOTES:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Shipped Convex-backed savings chat history sync with user-scoped sessions/messages, automatic per-user legacy localStorage import, server-persisted sendMessage flow, account-wide delete behavior, authorization coverage, and focused verification. Full lint still has unrelated pre-existing failures documented in notes.
+<!-- SECTION:FINAL_SUMMARY:END -->

convex/_generated/api.d.ts

@@ -35,6 +35,7 @@ import type * as lib_month from "../lib/month.js";
 import type * as lib_seedCategories from "../lib/seedCategories.js";
 import type * as loans from "../loans.js";
 import type * as savingsChat from "../savingsChat.js";
+import type * as savingsChatHistory from "../savingsChatHistory.js";
 import type * as settings from "../settings.js";
 import type * as transactions from "../transactions.js";
 import type * as users from "../users.js";
@@ -73,6 +74,7 @@ declare const fullApi: ApiFromModules<{
   "lib/seedCategories": typeof lib_seedCategories;
   loans: typeof loans;
   savingsChat: typeof savingsChat;
+  savingsChatHistory: typeof savingsChatHistory;
   settings: typeof settings;
   transactions: typeof transactions;
   users: typeof users;

convex/savingsChat.test.ts

@@ -2,6 +2,7 @@
 
 import { convexTest } from "convex-test";
 import { generateText } from "ai";
+import { makeFunctionReference } from "convex/server";
 import { beforeEach, describe, expect, test, vi } from "vitest";
 import { api, internal } from "./_generated/api";
 import type { Id } from "./_generated/dataModel";
@@ -57,6 +58,18 @@ vi.mock("ai", async (importOriginal) => {
 const modules = import.meta.glob("./**/*.ts");
 delete modules["./savingsChat.test.ts"];
 
+const historyApi = {
+  listSessions: makeFunctionReference<"query">("savingsChatHistory:listSessions"),
+  listMessages: makeFunctionReference<"query">("savingsChatHistory:listMessages"),
+  createSession: makeFunctionReference<"mutation">("savingsChatHistory:createSession"),
+  deleteSession: makeFunctionReference<"mutation">("savingsChatHistory:deleteSession"),
+  importLocalSession: makeFunctionReference<"mutation">("savingsChatHistory:importLocalSession"),
+};
+
+const sendMessageAction = makeFunctionReference<"action">("savingsChat:sendMessage");
+
+const paginationOpts = { cursor: null, numItems: 20 };
+
 beforeEach(() => {
   vi.clearAllMocks();
 });
@@ -205,6 +218,336 @@ async function seedSavingsInsightFixture() {
   };
 }
 
+describe("savingsChatHistory", () => {
+  test("keeps sessions and messages scoped to the authenticated user and hides deleted sessions", async () => {
+    const t = convexTest(schema, modules);
+    const seeded = await t.run(async (ctx) => {
+      const userId = await ctx.db.insert("users", { name: "Laptop User", email: "laptop@example.com" });
+      const otherUserId = await ctx.db.insert("users", { name: "PC User", email: "pc@example.com" });
+      return { userId, otherUserId };
+    });
+    const asUser = t.withIdentity({
+      subject: `${seeded.userId}|laptop`,
+      tokenIdentifier: `test:${seeded.userId}`,
+    });
+    const asOtherUser = t.withIdentity({
+      subject: `${seeded.otherUserId}|pc`,
+      tokenIdentifier: `test:${seeded.otherUserId}`,
+    });
+
+    const imported = await asUser.mutation(historyApi.importLocalSession, {
+      legacyLocalId: "local-laptop-chat",
+      title: "Laptop Chat",
+      createdAt: 1_700_000_000_000,
+      updatedAt: 1_700_000_100_000,
+      messages: [
+        { role: "assistant", content: "Frag mich zu deinen Umsätzen." },
+        { role: "user", content: "Wie viel habe ich gespart?" },
+        {
+          role: "assistant",
+          content: "Du hast 100 EUR gespart.",
+          toolTrace: [
+            {
+              name: "summarize_spending",
+              inputSummary: "Standard-Kontext",
+              resultSummary: "2 Umsätze, Saldo 100.00€, 1 Kategorien",
+            },
+          ],
+        },
+      ],
+    });
+
+    const userSessions = await asUser.query(historyApi.listSessions, { paginationOpts });
+    expect(userSessions.page).toMatchObject([
+      { _id: imported.sessionId, title: "Laptop Chat", messageCount: 3 },
+    ]);
+
+    const otherSessions = await asOtherUser.query(historyApi.listSessions, { paginationOpts });
+    expect(otherSessions.page).toEqual([]);
+
+    const messages = await asUser.query(historyApi.listMessages, {
+      sessionId: imported.sessionId,
+      paginationOpts,
+    });
+    expect([...messages.page].reverse()).toMatchObject([
+      { role: "assistant", content: "Frag mich zu deinen Umsätzen." },
+      { role: "user", content: "Wie viel habe ich gespart?" },
+      {
+        role: "assistant",
+        content: "Du hast 100 EUR gespart.",
+        toolTrace: [
+          {
+            name: "summarize_spending",
+            inputSummary: "Standard-Kontext",
+            resultSummary: "2 Umsätze, Saldo 100.00€, 1 Kategorien",
+          },
+        ],
+      },
+    ]);
+
+    await expect(
+      asOtherUser.query(historyApi.listMessages, {
+        sessionId: imported.sessionId,
+        paginationOpts,
+      }),
+    ).rejects.toThrow("Nicht autorisiert");
+
+    await expect(
+      asOtherUser.action(sendMessageAction, {
+        sessionId: imported.sessionId,
+        content: "Kann ich diesen Chat nutzen?",
+        from: "2026-02-01",
+        to: "2026-02-28",
+        basis: "effective",
+      }),
+    ).rejects.toThrow("Nicht autorisiert");
+
+    await expect(
+      asOtherUser.mutation(historyApi.deleteSession, { sessionId: imported.sessionId }),
+    ).rejects.toThrow("Nicht autorisiert");
+
+    await asUser.mutation(historyApi.deleteSession, { sessionId: imported.sessionId });
+    const sessionsAfterDelete = await asUser.query(historyApi.listSessions, { paginationOpts });
+    expect(sessionsAfterDelete.page).toEqual([]);
+  });
+
+  test("imports a legacy local session once per legacy id without duplicating messages", async () => {
+    const t = convexTest(schema, modules);
+    const seeded = await t.run(async (ctx) => {
+      const userId = await ctx.db.insert("users", { name: "Legacy User", email: "legacy@example.com" });
+      return { userId };
+    });
+    const asUser = t.withIdentity({
+      subject: `${seeded.userId}|legacy`,
+      tokenIdentifier: `test:${seeded.userId}`,
+    });
+
+    const input = {
+      legacyLocalId: "legacy-session-1",
+      title: "Alter Laptop-Chat",
+      createdAt: 1_700_000_000_000,
+      updatedAt: 1_700_000_500_000,
+      messages: [
+        { role: "assistant", content: "Hallo" },
+        { role: "user", content: "Was waren meine Fixkosten?" },
+      ],
+    };
+
+    const first = await asUser.mutation(historyApi.importLocalSession, input);
+    const second = await asUser.mutation(historyApi.importLocalSession, input);
+
+    expect(second.sessionId).toBe(first.sessionId);
+
+    const sessions = await asUser.query(historyApi.listSessions, { paginationOpts });
+    expect(sessions.page).toHaveLength(1);
+    expect(sessions.page[0]).toMatchObject({
+      _id: first.sessionId,
+      title: "Alter Laptop-Chat",
+      messageCount: 2,
+    });
+
+    const messages = await asUser.query(historyApi.listMessages, {
+      sessionId: first.sessionId,
+      paginationOpts,
+    });
+    expect(messages.page).toHaveLength(2);
+    expect([...messages.page].reverse().map((message: { content: string }) => message.content)).toEqual([
+      "Hallo",
+      "Was waren meine Fixkosten?",
+    ]);
+  });
+});
+
+describe("savingsChat.sendMessage", () => {
+  test("stores user and assistant messages with tool traces and uses recent Convex history", async () => {
+    const previousKey = process.env.OPENAI_API_KEY;
+    const previousModel = process.env.SAVINGS_CHAT_MODEL;
+    const t = convexTest(schema, modules);
+    const seeded = await t.run(async (ctx) => {
+      const userId = await ctx.db.insert("users", { name: "Chat User", email: "chat@example.com" });
+      const accountId = await ctx.db.insert("accounts", {
+        userId,
+        name: "Girokonto",
+        type: "checking",
+        openingBalance: 0,
+        currency: "EUR",
+        isArchived: false,
+      });
+      await ctx.db.insert("transactions", {
+        userId,
+        accountId,
+        bookingDate: "2026-02-01",
+        valueDate: "2026-02-01",
+        description: "Gehalt",
+        amount: 3000,
+        isPending: false,
+        effectiveMonth: "2026-02",
+      });
+      await ctx.db.insert("transactions", {
+        userId,
+        accountId,
+        bookingDate: "2026-02-10",
+        valueDate: "2026-02-10",
+        description: "Supermarkt",
+        amount: -120,
+        isPending: false,
+        effectiveMonth: "2026-02",
+      });
+      return { userId, accountId };
+    });
+    const asUser = t.withIdentity({
+      subject: `${seeded.userId}|chat`,
+      tokenIdentifier: `test:${seeded.userId}`,
+    });
+
+    try {
+      process.env.OPENAI_API_KEY = "test-key";
+      delete process.env.SAVINGS_CHAT_MODEL;
+
+      const created = await asUser.mutation(historyApi.createSession, { title: "Neuer Chat" });
+      for (let index = 0; index < 24; index++) {
+        await asUser.mutation(historyApi.importLocalSession, {
+          legacyLocalId: `history-${index}`,
+          title: `Historie ${index}`,
+          createdAt: index,
+          updatedAt: index,
+          messages: [{ role: "user", content: `Separate legacy message ${index}` }],
+        });
+      }
+
+      await t.run(async (ctx) => {
+        for (let index = 0; index < 24; index++) {
+          await ctx.db.insert("chatMessages", {
+            userId: seeded.userId,
+            sessionId: created.sessionId,
+            role: index % 2 === 0 ? "user" : "assistant",
+            content: `Vorige Nachricht ${index}`,
+            createdAt: index,
+          });
+        }
+        await ctx.db.patch(created.sessionId, {
+          messageCount: 25,
+          updatedAt: 24,
+        });
+      });
+
+      const result = await asUser.action(sendMessageAction, {
+        sessionId: created.sessionId,
+        content: "Wie sieht Februar aus?",
+        from: "2026-02-01",
+        to: "2026-02-28",
+        accountId: seeded.accountId as Id<"accounts">,
+        basis: "effective",
+      });
+
+      expect(result.answer).toBe("Agenten-Antwort");
+      expect(result.toolTrace).toHaveLength(2);
+
+      const generateCall = vi.mocked(generateText).mock.calls[0][0] as {
+        messages: Array<{ role: string; content: string }>;
+      };
+      expect(generateCall.messages).toHaveLength(20);
+      expect(generateCall.messages[0].content).toBe("Vorige Nachricht 6");
+      expect(generateCall.messages[generateCall.messages.length - 1]).toEqual({
+        role: "user",
+        content: "Wie sieht Februar aus?",
+      });
+
+      const messages = await asUser.query(historyApi.listMessages, {
+        sessionId: created.sessionId,
+        paginationOpts: { cursor: null, numItems: 40 },
+      });
+      expect([...messages.page].reverse().slice(-2)).toMatchObject([
+        { role: "user", content: "Wie sieht Februar aus?" },
+        {
+          role: "assistant",
+          content: "Agenten-Antwort",
+          toolTrace: [
+            {
+              name: "get_transactions",
+              inputSummary: "2026-02-01 bis 2026-02-28, Limit 2",
+              resultSummary: "2 Umsätze, Saldo 2880.00€, vollständig",
+            },
+            {
+              name: "summarize_spending",
+              inputSummary: "2026-02-01 bis 2026-02-28",
+              resultSummary: "2 Umsätze, Saldo 2880.00€, 1 Kategorien",
+            },
+          ],
+        },
+      ]);
+    } finally {
+      if (previousKey === undefined) {
+        delete process.env.OPENAI_API_KEY;
+      } else {
+        process.env.OPENAI_API_KEY = previousKey;
+      }
+      if (previousModel === undefined) {
+        delete process.env.SAVINGS_CHAT_MODEL;
+      } else {
+        process.env.SAVINGS_CHAT_MODEL = previousModel;
+      }
+    }
+  });
+
+  test("stores an assistant failure message when AI generation fails after the user message is saved", async () => {
+    const previousKey = process.env.OPENAI_API_KEY;
+    const previousModel = process.env.SAVINGS_CHAT_MODEL;
+    const t = convexTest(schema, modules);
+    const seeded = await t.run(async (ctx) => {
+      const userId = await ctx.db.insert("users", { name: "Failure User", email: "failure@example.com" });
+      return { userId };
+    });
+    const asUser = t.withIdentity({
+      subject: `${seeded.userId}|failure`,
+      tokenIdentifier: `test:${seeded.userId}`,
+    });
+
+    try {
+      process.env.OPENAI_API_KEY = "test-key";
+      delete process.env.SAVINGS_CHAT_MODEL;
+      vi.mocked(generateText)
+        .mockRejectedValueOnce(new Error("model failed 1"))
+        .mockRejectedValueOnce(new Error("model failed 2"))
+        .mockRejectedValueOnce(new Error("model failed 3"));
+
+      const created = await asUser.mutation(historyApi.createSession, { title: "Neuer Chat" });
+      await expect(
+        asUser.action(sendMessageAction, {
+          sessionId: created.sessionId,
+          content: "Warum geht das nicht?",
+          from: "2026-02-01",
+          to: "2026-02-28",
+          basis: "effective",
+        }),
+      ).rejects.toThrow("KI-Anfrage fehlgeschlagen");
+
+      const messages = await asUser.query(historyApi.listMessages, {
+        sessionId: created.sessionId,
+        paginationOpts: { cursor: null, numItems: 10 },
+      });
+      expect([...messages.page].reverse().slice(-2)).toMatchObject([
+        { role: "user", content: "Warum geht das nicht?" },
+        {
+          role: "assistant",
+          content: "Ich konnte gerade keine Antwort erzeugen. Bitte später erneut versuchen.",
+        },
+      ]);
+    } finally {
+      if (previousKey === undefined) {
+        delete process.env.OPENAI_API_KEY;
+      } else {
+        process.env.OPENAI_API_KEY = previousKey;
+      }
+      if (previousModel === undefined) {
+        delete process.env.SAVINGS_CHAT_MODEL;
+      } else {
+        process.env.SAVINGS_CHAT_MODEL = previousModel;
+      }
+    }
+  });
+});
+
 describe("savingsChat.getContext", () => {
   test("counts and sums every matching transaction before applying prompt limits", async () => {
     const t = convexTest(schema, modules);

convex/savingsChat.ts

@@ -7,7 +7,7 @@ import { z } from "zod";
 import { addMonthsToMonthKey, bookingMonth, monthKeyFromBasis } from "./lib/month";
 import { requireUserId } from "./lib/helpers";
 import type { Doc, Id } from "./_generated/dataModel";
-import type { QueryCtx } from "./_generated/server";
+import type { ActionCtx, QueryCtx } from "./_generated/server";
 
 type ChatRole = "user" | "assistant";
 type ChatMessage = { role: ChatRole; content: string };
@@ -1900,6 +1900,202 @@ const fixedCostsForecastToolInputSchema = z.object({
   asOf: z.string().optional().describe("Stichtag für den Start der Prognose im Format YYYY-MM-DD."),
 });
 
+async function generateSavingsChatResponse(
+  ctx: ActionCtx,
+  args: ChatContextArgs & { messages: ChatMessage[] },
+): Promise<ChatAskResult> {
+  if (args.messages.length === 0) {
+    throw new Error("Kein Nutzernachrichttext vorhanden.");
+  }
+
+  if (!process.env.OPENAI_API_KEY) {
+    throw new Error(
+      "OPENAI_API_KEY ist nicht gesetzt. Bitte API-Key in den Convex-Umgebungsvariablen hinterlegen.",
+    );
+  }
+
+  await requireUserId(ctx);
+  const scope: AgentToolScope = {
+    from: args.from,
+    to: args.to,
+    accountId: args.accountId,
+    basis: args.basis,
+  };
+
+  const selectedSummary: {
+    totalCount: number;
+    totals: { income: number; expenses: number; balance: number; transactionCount: number };
+    accountName?: string;
+  } = await ctx.runQuery(internal.savingsChat.getTransactionsTool, {
+    scope,
+    limit: 1,
+  });
+
+  const lastMessages = args.messages
+    .map((message): ChatMessage => ({ role: normalizeRole(message.role), content: message.content }))
+    .slice(-MAX_CONVERSATION_MESSAGES);
+
+  const system = buildSystemPrompt({
+    from: args.from,
+    to: args.to,
+    basis: args.basis,
+    accountName: selectedSummary.accountName,
+  });
+
+  const savingsTools = {
+    get_transactions: tool({
+      description:
+        "Ruft passende Umsätze read-only ab. Nutze dieses Tool für Detailfragen, Suche nach Gegenparteien/Beschreibungen oder Belege einzelner Aussagen. Es liefert exakte Summen und nur begrenzte, sanitizte Zeilen.",
+      inputSchema: transactionToolInputSchema,
+      execute: async (input) =>
+        await ctx.runQuery(internal.savingsChat.getTransactionsTool, {
+          scope,
+          ...input,
+        }),
+    }),
+    summarize_spending: tool({
+      description:
+        "Berechnet read-only exakte Summen, Monatsverläufe, Kategorien sowie fixe und variable Ausgaben für den ausgewählten oder angegebenen Zeitraum.",
+      inputSchema: summaryToolInputSchema,
+      execute: async (input) =>
+        await ctx.runQuery(internal.savingsChat.summarizeSpendingTool, {
+          scope,
+          ...input,
+        }),
+    }),
+    forecast_cashflow: tool({
+      description:
+        "Erstellt eine deterministische Cashflow-Prognose für 1 bis 3 kommende Monate aus vollständigen historischen Monaten. Nutze es für Sparrate, Monatsüberschuss und kurzfristige Prognosen.",
+      inputSchema: forecastToolInputSchema,
+      execute: async (input) =>
+        await ctx.runQuery(internal.savingsChat.forecastCashflowTool, {
+          scope,
+          ...input,
+        }),
+    }),
+    get_accounts: tool({
+      description:
+        "Listet read-only Konten mit Typ, Währung, Archivstatus, Startsaldo, Umsatzanzahl und Zeitraumssaldo. Nutze es für Fragen nach Konten, Konto-Scope oder Datenabdeckung.",
+      inputSchema: accountToolInputSchema,
+      execute: async (input) =>
+        await ctx.runQuery(internal.savingsChat.getAccountsTool, {
+          scope,
+          ...input,
+        }),
+    }),
+    get_categories: tool({
+      description:
+        "Listet read-only Kategorien mit Art, Fix/Variabel-Block, Umsatzanzahl, Summe und Ausgabenanteil im Zeitraum. Nutze es für Kategorie- und Budgetstrukturfragen.",
+      inputSchema: summaryToolInputSchema,
+      execute: async (input) =>
+        await ctx.runQuery(internal.savingsChat.getCategoriesTool, {
+          scope,
+          ...input,
+        }),
+    }),
+    detect_recurring_transactions: tool({
+      description:
+        "Erkennt deterministisch monatlich wiederkehrende Muster nach Beschreibung, Gegenpartei, Kategorie und stabiler Betragshöhe. Nutze es für Miete, Gehalt, Abos und regelmäßige Abbuchungen.",
+      inputSchema: recurringToolInputSchema,
+      execute: async (input) =>
+        await ctx.runQuery(internal.savingsChat.detectRecurringTransactionsTool, {
+          scope,
+          ...input,
+        }),
+    }),
+    find_anomalies: tool({
+      description:
+        "Findet read-only auffällige Betragsausreißer und fehlende erwartete wiederkehrende Buchungen gegenüber historischen Mustern.",
+      inputSchema: anomalyToolInputSchema,
+      execute: async (input) =>
+        await ctx.runQuery(internal.savingsChat.findAnomaliesTool, {
+          scope,
+          ...input,
+        }),
+    }),
+    get_uncategorized_transactions: tool({
+      description:
+        "Ruft bounded und sanitizt unklassifizierte Umsätze mit Summen und Top-Gegenparteien ab. Nutze es für Datenqualität und Fragen nach fehlenden Kategorien.",
+      inputSchema: uncategorizedToolInputSchema,
+      execute: async (input) =>
+        await ctx.runQuery(internal.savingsChat.getUncategorizedTransactionsTool, {
+          scope,
+          ...input,
+        }),
+    }),
+    compare_periods: tool({
+      description:
+        "Vergleicht zwei Zeiträume deterministisch mit Totals, Monatsverlauf, Kategorie-Deltas und Fix/Variabel-Deltas.",
+      inputSchema: comparePeriodsToolInputSchema,
+      execute: async (input) =>
+        await ctx.runQuery(internal.savingsChat.comparePeriodsTool, {
+          scope,
+          ...input,
+        }),
+    }),
+    forecast_fixed_costs: tool({
+      description:
+        "Prognostiziert wiederkehrende Fixkosten für 1 bis 6 Monate aus Fixkosten-Kategorien und stabilen historischen Monatsmustern.",
+      inputSchema: fixedCostsForecastToolInputSchema,
+      execute: async (input) =>
+        await ctx.runQuery(internal.savingsChat.forecastFixedCostsTool, {
+          scope,
+          ...input,
+        }),
+    }),
+    explain_savings_rate: tool({
+      description:
+        "Berechnet Sparquote, gesparten Betrag, fixe und variable Kostenquote, Haupttreiber und konkrete Hebel aus exakten Aggregaten.",
+      inputSchema: summaryToolInputSchema,
+      execute: async (input) =>
+        await ctx.runQuery(internal.savingsChat.explainSavingsRateTool, {
+          scope,
+          ...input,
+        }),
+    }),
+  };
+
+  const envModel = process.env.SAVINGS_CHAT_MODEL?.trim();
+  const candidates = [
+    envModel,
+    "gpt-5.4-mini",
+    "gpt-4.1-mini",
+    "gpt-4.1",
+  ].filter(Boolean) as string[];
+
+  let lastError: unknown;
+  for (const modelName of candidates) {
+    try {
+      const result = await generateText({
+        model: openai(modelName),
+        system,
+        messages: lastMessages,
+        tools: savingsTools,
+        stopWhen: stepCountIs(5),
+      });
+      return {
+        model: modelName,
+        answer: result.text,
+        usedTransactions: selectedSummary.totals.transactionCount,
+        usedBalance: {
+          income: selectedSummary.totals.income,
+          expenses: selectedSummary.totals.expenses,
+          balance: selectedSummary.totals.balance,
+        },
+        toolTrace: buildToolTraceFromSteps(result.steps),
+      };
+    } catch (error) {
+      lastError = error;
+    }
+  }
+
+  const message =
+    lastError instanceof Error
+      ? lastError.message
+      : "Unbekannter Fehler bei der KI-Anfrage";
+  throw new Error(`KI-Anfrage fehlgeschlagen: ${message}`);
+}
+
 export const ask = action({
   args: {
     messages: v.array(chatMessageValidator),
@@ -1920,195 +2116,74 @@ export const ask = action({
     toolTrace: v.array(toolTraceValidator),
   }),
   handler: async (ctx, args): Promise<ChatAskResult> => {
-    if (args.messages.length === 0) {
+    return await generateSavingsChatResponse(ctx, {
+      ...args,
+      messages: args.messages.map((message) => ({
+        role: normalizeRole(message.role),
+        content: message.content,
+      })),
+    });
+  },
+});
+
+export const sendMessage = action({
+  args: {
+    sessionId: v.id("chatSessions"),
+    content: v.string(),
+    from: v.string(),
+    to: v.string(),
+    accountId: v.optional(v.id("accounts")),
+    basis: v.union(v.literal("effective"), v.literal("booking")),
+  },
+  returns: v.object({
+    model: v.string(),
+    answer: v.string(),
+    usedTransactions: v.number(),
+    usedBalance: v.object({
+      income: v.number(),
+      expenses: v.number(),
+      balance: v.number(),
+    }),
+    toolTrace: v.array(toolTraceValidator),
+  }),
+  handler: async (ctx, args): Promise<ChatAskResult> => {
+    const content = args.content.trim();
+    if (!content) {
       throw new Error("Kein Nutzernachrichttext vorhanden.");
     }
 
-    if (!process.env.OPENAI_API_KEY) {
+    await ctx.runMutation(internal.savingsChatHistory.appendUserMessage, {
-      throw new Error(
+      sessionId: args.sessionId,
-        "OPENAI_API_KEY ist nicht gesetzt. Bitte API-Key in den Convex-Umgebungsvariablen hinterlegen.",
+      content,
-      );
-    }
-
-    await requireUserId(ctx);
-    const scope: AgentToolScope = {
-      from: args.from,
-      to: args.to,
-      accountId: args.accountId,
-      basis: args.basis,
-    };
-
-    const selectedSummary: {
-      totalCount: number;
-      totals: { income: number; expenses: number; balance: number; transactionCount: number };
-      accountName?: string;
-    } = await ctx.runQuery(internal.savingsChat.getTransactionsTool, {
-      scope,
-      limit: 1,
     });
-
+    const messages: ChatMessage[] = await ctx.runQuery(
-    const lastMessages = args.messages
+      internal.savingsChatHistory.getRecentMessagesForPrompt,
-      .map((message): ChatMessage => ({ role: normalizeRole(message.role), content: message.content }))
+      {
-      .slice(-MAX_CONVERSATION_MESSAGES);
+        sessionId: args.sessionId,
-
+        limit: MAX_CONVERSATION_MESSAGES,
-    const system = buildSystemPrompt({
+      },
-      from: args.from,
+    );
-      to: args.to,
+    let response: ChatAskResult;
-      basis: args.basis,
+    try {
-      accountName: selectedSummary.accountName,
+      response = await generateSavingsChatResponse(ctx, {
-    });
+        from: args.from,
-
+        to: args.to,
-    const savingsTools = {
+        accountId: args.accountId,
-      get_transactions: tool({
+        basis: args.basis,
-        description:
+        messages,
-          "Ruft passende Umsätze read-only ab. Nutze dieses Tool für Detailfragen, Suche nach Gegenparteien/Beschreibungen oder Belege einzelner Aussagen. Es liefert exakte Summen und nur begrenzte, sanitizte Zeilen.",
+      });
-        inputSchema: transactionToolInputSchema,
+    } catch (error) {
-        execute: async (input) =>
+      await ctx.runMutation(internal.savingsChatHistory.appendAssistantMessage, {
-          await ctx.runQuery(internal.savingsChat.getTransactionsTool, {
+        sessionId: args.sessionId,
-            scope,
+        content: "Ich konnte gerade keine Antwort erzeugen. Bitte später erneut versuchen.",
-            ...input,
+      });
-          }),
+      throw error;
-      }),
-      summarize_spending: tool({
-        description:
-          "Berechnet read-only exakte Summen, Monatsverläufe, Kategorien sowie fixe und variable Ausgaben für den ausgewählten oder angegebenen Zeitraum.",
-        inputSchema: summaryToolInputSchema,
-        execute: async (input) =>
-          await ctx.runQuery(internal.savingsChat.summarizeSpendingTool, {
-            scope,
-            ...input,
-          }),
-      }),
-      forecast_cashflow: tool({
-        description:
-          "Erstellt eine deterministische Cashflow-Prognose für 1 bis 3 kommende Monate aus vollständigen historischen Monaten. Nutze es für Sparrate, Monatsüberschuss und kurzfristige Prognosen.",
-        inputSchema: forecastToolInputSchema,
-        execute: async (input) =>
-          await ctx.runQuery(internal.savingsChat.forecastCashflowTool, {
-            scope,
-            ...input,
-          }),
-      }),
-      get_accounts: tool({
-        description:
-          "Listet read-only Konten mit Typ, Währung, Archivstatus, Startsaldo, Umsatzanzahl und Zeitraumssaldo. Nutze es für Fragen nach Konten, Konto-Scope oder Datenabdeckung.",
-        inputSchema: accountToolInputSchema,
-        execute: async (input) =>
-          await ctx.runQuery(internal.savingsChat.getAccountsTool, {
-            scope,
-            ...input,
-          }),
-      }),
-      get_categories: tool({
-        description:
-          "Listet read-only Kategorien mit Art, Fix/Variabel-Block, Umsatzanzahl, Summe und Ausgabenanteil im Zeitraum. Nutze es für Kategorie- und Budgetstrukturfragen.",
-        inputSchema: summaryToolInputSchema,
-        execute: async (input) =>
-          await ctx.runQuery(internal.savingsChat.getCategoriesTool, {
-            scope,
-            ...input,
-          }),
-      }),
-      detect_recurring_transactions: tool({
-        description:
-          "Erkennt deterministisch monatlich wiederkehrende Muster nach Beschreibung, Gegenpartei, Kategorie und stabiler Betragshöhe. Nutze es für Miete, Gehalt, Abos und regelmäßige Abbuchungen.",
-        inputSchema: recurringToolInputSchema,
-        execute: async (input) =>
-          await ctx.runQuery(internal.savingsChat.detectRecurringTransactionsTool, {
-            scope,
-            ...input,
-          }),
-      }),
-      find_anomalies: tool({
-        description:
-          "Findet read-only auffällige Betragsausreißer und fehlende erwartete wiederkehrende Buchungen gegenüber historischen Mustern.",
-        inputSchema: anomalyToolInputSchema,
-        execute: async (input) =>
-          await ctx.runQuery(internal.savingsChat.findAnomaliesTool, {
-            scope,
-            ...input,
-          }),
-      }),
-      get_uncategorized_transactions: tool({
-        description:
-          "Ruft bounded und sanitizt unklassifizierte Umsätze mit Summen und Top-Gegenparteien ab. Nutze es für Datenqualität und Fragen nach fehlenden Kategorien.",
-        inputSchema: uncategorizedToolInputSchema,
-        execute: async (input) =>
-          await ctx.runQuery(internal.savingsChat.getUncategorizedTransactionsTool, {
-            scope,
-            ...input,
-          }),
-      }),
-      compare_periods: tool({
-        description:
-          "Vergleicht zwei Zeiträume deterministisch mit Totals, Monatsverlauf, Kategorie-Deltas und Fix/Variabel-Deltas.",
-        inputSchema: comparePeriodsToolInputSchema,
-        execute: async (input) =>
-          await ctx.runQuery(internal.savingsChat.comparePeriodsTool, {
-            scope,
-            ...input,
-          }),
-      }),
-      forecast_fixed_costs: tool({
-        description:
-          "Prognostiziert wiederkehrende Fixkosten für 1 bis 6 Monate aus Fixkosten-Kategorien und stabilen historischen Monatsmustern.",
-        inputSchema: fixedCostsForecastToolInputSchema,
-        execute: async (input) =>
-          await ctx.runQuery(internal.savingsChat.forecastFixedCostsTool, {
-            scope,
-            ...input,
-          }),
-      }),
-      explain_savings_rate: tool({
-        description:
-          "Berechnet Sparquote, gesparten Betrag, fixe und variable Kostenquote, Haupttreiber und konkrete Hebel aus exakten Aggregaten.",
-        inputSchema: summaryToolInputSchema,
-        execute: async (input) =>
-          await ctx.runQuery(internal.savingsChat.explainSavingsRateTool, {
-            scope,
-            ...input,
-          }),
-      }),
-    };
-
-    const envModel = process.env.SAVINGS_CHAT_MODEL?.trim();
-    const candidates = [
-      envModel,
-      "gpt-5.4-mini",
-      "gpt-4.1-mini",
-      "gpt-4.1",
-    ].filter(Boolean) as string[];
-
-    let lastError: unknown;
-    for (const modelName of candidates) {
-      try {
-        const result = await generateText({
-          model: openai(modelName),
-          system,
-          messages: lastMessages,
-          tools: savingsTools,
-          stopWhen: stepCountIs(5),
-        });
-        return {
-          model: modelName,
-          answer: result.text,
-          usedTransactions: selectedSummary.totals.transactionCount,
-          usedBalance: {
-            income: selectedSummary.totals.income,
-            expenses: selectedSummary.totals.expenses,
-            balance: selectedSummary.totals.balance,
-          },
-          toolTrace: buildToolTraceFromSteps(result.steps),
-        };
-      } catch (error) {
-        lastError = error;
-      }
     }
-
+    await ctx.runMutation(internal.savingsChatHistory.appendAssistantMessage, {
-    const message =
+      sessionId: args.sessionId,
-      lastError instanceof Error
+      content: response.answer,
-        ? lastError.message
+      toolTrace: response.toolTrace,
-        : "Unbekannter Fehler bei der KI-Anfrage";
+    });
-    throw new Error(`KI-Anfrage fehlgeschlagen: ${message}`);
+    return response;
   },
 });

convex/savingsChatHistory.ts

@@ -0,0 +1,266 @@
+import { paginationOptsValidator, paginationResultValidator } from "convex/server";
+import { v } from "convex/values";
+import { internalMutation, internalQuery, mutation, query } from "./_generated/server";
+import type { Id } from "./_generated/dataModel";
+import type { MutationCtx, QueryCtx } from "./_generated/server";
+import { assertOwned, requireUserId } from "./lib/helpers";
+
+const initialAssistantMessage =
+  "Frag mich zu deinen Umsätzen – ich werte sie im aktuellen Zeitraum aus.";
+
+const toolTraceValidator = v.object({
+  name: v.string(),
+  inputSummary: v.string(),
+  resultSummary: v.string(),
+});
+
+const chatRoleValidator = v.union(v.literal("user"), v.literal("assistant"));
+
+const importMessageValidator = v.object({
+  role: chatRoleValidator,
+  content: v.string(),
+  toolTrace: v.optional(v.array(toolTraceValidator)),
+});
+
+const sessionValidator = v.object({
+  _id: v.id("chatSessions"),
+  _creationTime: v.number(),
+  userId: v.id("users"),
+  title: v.string(),
+  createdAt: v.number(),
+  updatedAt: v.number(),
+  messageCount: v.number(),
+  legacyLocalId: v.optional(v.string()),
+  isDeleted: v.boolean(),
+});
+
+const messageValidator = v.object({
+  _id: v.id("chatMessages"),
+  _creationTime: v.number(),
+  userId: v.id("users"),
+  sessionId: v.id("chatSessions"),
+  role: chatRoleValidator,
+  content: v.string(),
+  createdAt: v.number(),
+  toolTrace: v.optional(v.array(toolTraceValidator)),
+});
+
+const promptMessageValidator = v.object({
+  role: chatRoleValidator,
+  content: v.string(),
+});
+
+function normalizeTitle(title: string | undefined) {
+  const trimmed = title?.trim();
+  return trimmed ? trimmed : "Neuer Chat";
+}
+
+function titleFromContent(content: string) {
+  const trimmed = content.trim();
+  if (!trimmed) return "Neuer Chat";
+  return trimmed.length > 44 ? `${trimmed.slice(0, 44)}…` : trimmed;
+}
+
+async function requireOwnedSession(
+  ctx: QueryCtx | MutationCtx,
+  sessionId: Id<"chatSessions">,
+  userId: Id<"users">,
+) {
+  const session = await assertOwned(await ctx.db.get(sessionId), userId, "Chat");
+  if (session.isDeleted) throw new Error("Chat nicht gefunden");
+  return session;
+}
+
+export const listSessions = query({
+  args: { paginationOpts: paginationOptsValidator },
+  returns: paginationResultValidator(sessionValidator),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    return await ctx.db
+      .query("chatSessions")
+      .withIndex("by_user_deleted_updated", (index) =>
+        index.eq("userId", userId).eq("isDeleted", false),
+      )
+      .order("desc")
+      .paginate(args.paginationOpts);
+  },
+});
+
+export const listMessages = query({
+  args: {
+    sessionId: v.id("chatSessions"),
+    paginationOpts: paginationOptsValidator,
+  },
+  returns: paginationResultValidator(messageValidator),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    await requireOwnedSession(ctx, args.sessionId, userId);
+    return await ctx.db
+      .query("chatMessages")
+      .withIndex("by_user_session_created", (index) =>
+        index.eq("userId", userId).eq("sessionId", args.sessionId),
+      )
+      .order("desc")
+      .paginate(args.paginationOpts);
+  },
+});
+
+export const createSession = mutation({
+  args: { title: v.optional(v.string()) },
+  returns: v.object({ sessionId: v.id("chatSessions") }),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    const now = Date.now();
+    const sessionId = await ctx.db.insert("chatSessions", {
+      userId,
+      title: normalizeTitle(args.title),
+      createdAt: now,
+      updatedAt: now,
+      messageCount: 1,
+      isDeleted: false,
+    });
+    await ctx.db.insert("chatMessages", {
+      userId,
+      sessionId,
+      role: "assistant",
+      content: initialAssistantMessage,
+      createdAt: now,
+    });
+    return { sessionId };
+  },
+});
+
+export const deleteSession = mutation({
+  args: { sessionId: v.id("chatSessions") },
+  returns: v.null(),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    await requireOwnedSession(ctx, args.sessionId, userId);
+    await ctx.db.patch(args.sessionId, {
+      isDeleted: true,
+      updatedAt: Date.now(),
+    });
+    return null;
+  },
+});
+
+export const importLocalSession = mutation({
+  args: {
+    legacyLocalId: v.string(),
+    title: v.string(),
+    createdAt: v.number(),
+    updatedAt: v.number(),
+    messages: v.array(importMessageValidator),
+  },
+  returns: v.object({ sessionId: v.id("chatSessions") }),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    const existing = await ctx.db
+      .query("chatSessions")
+      .withIndex("by_user_legacyLocalId", (index) =>
+        index.eq("userId", userId).eq("legacyLocalId", args.legacyLocalId),
+      )
+      .unique();
+    if (existing) return { sessionId: existing._id };
+
+    const sessionId = await ctx.db.insert("chatSessions", {
+      userId,
+      title: normalizeTitle(args.title),
+      createdAt: args.createdAt,
+      updatedAt: args.updatedAt,
+      messageCount: args.messages.length,
+      legacyLocalId: args.legacyLocalId,
+      isDeleted: false,
+    });
+
+    for (const [index, message] of args.messages.entries()) {
+      await ctx.db.insert("chatMessages", {
+        userId,
+        sessionId,
+        role: message.role,
+        content: message.content,
+        createdAt: args.createdAt + index,
+        ...(message.toolTrace ? { toolTrace: message.toolTrace } : {}),
+      });
+    }
+
+    return { sessionId };
+  },
+});
+
+export const appendUserMessage = internalMutation({
+  args: {
+    sessionId: v.id("chatSessions"),
+    content: v.string(),
+  },
+  returns: v.object({ messageId: v.id("chatMessages") }),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    const session = await requireOwnedSession(ctx, args.sessionId, userId);
+    const now = Date.now();
+    const messageId = await ctx.db.insert("chatMessages", {
+      userId,
+      sessionId: args.sessionId,
+      role: "user",
+      content: args.content,
+      createdAt: now,
+    });
+    await ctx.db.patch(args.sessionId, {
+      title: session.title === "Neuer Chat" ? titleFromContent(args.content) : session.title,
+      updatedAt: now,
+      messageCount: session.messageCount + 1,
+    });
+    return { messageId };
+  },
+});
+
+export const appendAssistantMessage = internalMutation({
+  args: {
+    sessionId: v.id("chatSessions"),
+    content: v.string(),
+    toolTrace: v.optional(v.array(toolTraceValidator)),
+  },
+  returns: v.object({ messageId: v.id("chatMessages") }),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    const session = await requireOwnedSession(ctx, args.sessionId, userId);
+    const now = Date.now();
+    const messageId = await ctx.db.insert("chatMessages", {
+      userId,
+      sessionId: args.sessionId,
+      role: "assistant",
+      content: args.content,
+      createdAt: now,
+      ...(args.toolTrace ? { toolTrace: args.toolTrace } : {}),
+    });
+    await ctx.db.patch(args.sessionId, {
+      updatedAt: now,
+      messageCount: session.messageCount + 1,
+    });
+    return { messageId };
+  },
+});
+
+export const getRecentMessagesForPrompt = internalQuery({
+  args: {
+    sessionId: v.id("chatSessions"),
+    limit: v.number(),
+  },
+  returns: v.array(promptMessageValidator),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    await requireOwnedSession(ctx, args.sessionId, userId);
+    const limit = Math.max(1, Math.min(50, Math.floor(args.limit)));
+    const messages = await ctx.db
+      .query("chatMessages")
+      .withIndex("by_user_session_created", (index) =>
+        index.eq("userId", userId).eq("sessionId", args.sessionId),
+      )
+      .order("desc")
+      .take(limit);
+    return messages.reverse().map((message) => ({
+      role: message.role,
+      content: message.content,
+    }));
+  },
+});

convex/schema.ts

@@ -9,6 +9,12 @@ const loanStatus = v.union(
   v.literal("abbezahlt"),
   v.literal("pausiert"),
 );
+const chatRole = v.union(v.literal("user"), v.literal("assistant"));
+const chatToolTrace = v.object({
+  name: v.string(),
+  inputSummary: v.string(),
+  resultSummary: v.string(),
+});
 
 export default defineSchema({
   ...authTables,
@@ -175,4 +181,25 @@ export default defineSchema({
     isDecoupled: v.optional(v.boolean()),
     submittedTan: v.optional(v.string()),
   }).index("by_user", ["userId"]),
+
+  chatSessions: defineTable({
+    userId: v.id("users"),
+    title: v.string(),
+    createdAt: v.number(),
+    updatedAt: v.number(),
+    messageCount: v.number(),
+    legacyLocalId: v.optional(v.string()),
+    isDeleted: v.boolean(),
+  })
+    .index("by_user_deleted_updated", ["userId", "isDeleted", "updatedAt"])
+    .index("by_user_legacyLocalId", ["userId", "legacyLocalId"]),
+
+  chatMessages: defineTable({
+    userId: v.id("users"),
+    sessionId: v.id("chatSessions"),
+    role: chatRole,
+    content: v.string(),
+    createdAt: v.number(),
+    toolTrace: v.optional(v.array(chatToolTrace)),
+  }).index("by_user_session_created", ["userId", "sessionId", "createdAt"]),
 });

src/pages/SavingsChatPage.tsx

@@ -1,7 +1,8 @@
-import { type FormEvent, useEffect, useRef, useState } from "react";
+import { type FormEvent, useEffect, useMemo, useRef, useState } from "react";
-import { useAction, useQuery } from "convex/react";
+import { useAction, useMutation, usePaginatedQuery, useQuery } from "convex/react";
 import { MessageCircle, Send, Loader2 } from "lucide-react";
 import { api } from "../../convex/_generated/api";
+import type { Id } from "../../convex/_generated/dataModel";
 import { useAccountFilterId } from "@/components/layout/AccountFilter";
 import { useFilters } from "@/context/FilterContext";
 import { Button } from "@/components/ui/button";
@@ -23,20 +24,22 @@ type AssistantChatMessage = {
   toolTrace?: ToolTrace[];
 };
 type ChatMessage = UserChatMessage | AssistantChatMessage;
-type ChatSession = {
+type LegacyChatSession = {
   id: string;
   title: string;
   createdAt: number;
   updatedAt: number;
   messages: ChatMessage[];
 };
+type DisplayChatMessage = ChatMessage & { _id: string };
 
 const STORAGE_KEY = "savings-chat-sessions";
+const IMPORTED_KEY = "savings-chat-sessions-imported-v1";
 const initialAssistantMessage: ChatMessage = {
   role: "assistant",
   content: "Frag mich zu deinen Umsätzen – ich werte sie im aktuellen Zeitraum aus.",
 };
-const fallbackMessages = [initialAssistantMessage];
+const fallbackMessages: DisplayChatMessage[] = [{ ...initialAssistantMessage, _id: "fallback-0" }];
 
 function normalizeToolTrace(value: unknown): ToolTrace[] | undefined {
   if (!Array.isArray(value)) return undefined;
@@ -84,7 +87,7 @@ function isChatMessage(value: ChatMessage | null): value is ChatMessage {
   return value !== null;
 }
 
-function normalizeSession(value: unknown): ChatSession | null {
+function normalizeSession(value: unknown): LegacyChatSession | null {
   if (!value || typeof value !== "object") return null;
   const candidate = value as Record<string, unknown>;
   if (
@@ -109,53 +112,57 @@ function normalizeSession(value: unknown): ChatSession | null {
   };
 }
 
-function createSession(): ChatSession {
+function loadLegacySessions(): LegacyChatSession[] {
-  const now = Date.now();
-  const randomId =
-    typeof crypto !== "undefined" && "randomUUID" in crypto
-      ? crypto.randomUUID()
-      : `${now}-${Math.random().toString(36).slice(2)}`;
-
-  return {
-    id: randomId,
-    title: "Neuer Chat",
-    createdAt: now,
-    updatedAt: now,
-    messages: [initialAssistantMessage],
-  };
-}
-
-function loadSessions(): ChatSession[] {
   try {
     const raw = localStorage.getItem(STORAGE_KEY);
-    if (!raw) return [createSession()];
+    if (!raw) return [];
     const parsed: unknown = JSON.parse(raw);
-    if (!Array.isArray(parsed) || parsed.length === 0) return [createSession()];
+    if (!Array.isArray(parsed)) return [];
-    const sessions = parsed.map(normalizeSession);
+    return parsed
-    if (sessions.some((session) => session === null)) return [createSession()];
+      .map(normalizeSession)
-    return sessions as ChatSession[];
+      .filter((session): session is LegacyChatSession => session !== null)
+      .filter((session) => session.messages.some((message) => message.role === "user"));
   } catch {
-    return [createSession()];
+    return [];
   }
 }
 
-function titleFromMessages(messages: ChatMessage[]) {
-  const firstUserMessage = messages.find((message) => message.role === "user")?.content.trim();
-  if (!firstUserMessage) return "Neuer Chat";
-  return firstUserMessage.length > 44 ? `${firstUserMessage.slice(0, 44)}…` : firstUserMessage;
-}
-
 export function SavingsChatPage() {
   const { from, to, monthBasis } = useFilters();
   const accountId = useAccountFilterId();
 
   const [draft, setDraft] = useState("");
-  const [sessions, setSessions] = useState<ChatSession[]>(loadSessions);
+  const [selectedSessionId, setSelectedSessionId] = useState<Id<"chatSessions"> | undefined>();
-  const [activeSessionId, setActiveSessionId] = useState(() => sessions[0]?.id ?? "");
   const [isSubmitting, setIsSubmitting] = useState(false);
+  const [legacyImportResult, setLegacyImportResult] = useState<{
+    key: string;
+    importedCount: number;
+  } | null>(null);
+  const legacyImportStartedRef = useRef<string | undefined>(undefined);
+  const createInitialStartedRef = useRef(false);
   const listRef = useRef<HTMLDivElement | null>(null);
-  const activeSession = sessions.find((session) => session.id === activeSessionId) ?? sessions[0];
+
-  const messages = activeSession?.messages ?? fallbackMessages;
+  const sessionsQuery = usePaginatedQuery(
+    api.savingsChatHistory.listSessions,
+    {},
+    { initialNumItems: 50 },
+  );
+  const sessions = sessionsQuery.results;
+  const activeSessionId =
+    selectedSessionId && sessions.some((session) => session._id === selectedSessionId)
+      ? selectedSessionId
+      : sessions[0]?._id;
+  const activeSession = sessions.find((session) => session._id === activeSessionId);
+  const messagesQuery = usePaginatedQuery(
+    api.savingsChatHistory.listMessages,
+    activeSessionId ? { sessionId: activeSessionId } : "skip",
+    { initialNumItems: 100 },
+  );
+  const messages = useMemo(
+    () => [...messagesQuery.results].reverse() as DisplayChatMessage[],
+    [messagesQuery.results],
+  );
+  const displayMessages = activeSessionId && messages.length > 0 ? messages : fallbackMessages;
 
   const context = useQuery(api.savingsChat.getContext, {
     from,
@@ -163,9 +170,23 @@ export function SavingsChatPage() {
     accountId,
     basis: monthBasis,
   });
-  const ask = useAction(api.savingsChat.ask);
+  const currentUser = useQuery(api.users.currentUser);
+  const createSession = useMutation(api.savingsChatHistory.createSession);
+  const deleteSession = useMutation(api.savingsChatHistory.deleteSession);
+  const importLocalSession = useMutation(api.savingsChatHistory.importLocalSession);
+  const sendMessage = useAction(api.savingsChat.sendMessage);
+  const importMarkerKey = currentUser ? `${IMPORTED_KEY}:${currentUser._id}` : undefined;
+  const legacyImportComplete = Boolean(
+    importMarkerKey &&
+      (legacyImportResult?.key === importMarkerKey ||
+        localStorage.getItem(importMarkerKey) === "true"),
+  );
+  const legacyImportedCount =
+    legacyImportResult && legacyImportResult.key === importMarkerKey
+      ? legacyImportResult.importedCount
+      : 0;
 
-  const buttonDisabled = isSubmitting || draft.trim().length === 0;
+  const buttonDisabled = isSubmitting || draft.trim().length === 0 || !activeSessionId;
 
   const formatAmount = (amount: number) =>
     new Intl.NumberFormat("de-DE", {
@@ -182,92 +203,120 @@ export function SavingsChatPage() {
 
   useEffect(() => {
     listRef.current?.lastElementChild?.scrollIntoView({ behavior: "smooth" });
-  }, [messages]);
+  }, [displayMessages.length, activeSessionId]);
 
   useEffect(() => {
-    localStorage.setItem(STORAGE_KEY, JSON.stringify(sessions));
+    if (!importMarkerKey || legacyImportComplete || legacyImportStartedRef.current === importMarkerKey) return;
-  }, [sessions]);
+    legacyImportStartedRef.current = importMarkerKey;
+    const legacySessions = loadLegacySessions();
+    if (legacySessions.length === 0) {
+      localStorage.setItem(importMarkerKey, "true");
+      void Promise.resolve().then(() =>
+        setLegacyImportResult({ key: importMarkerKey, importedCount: 0 }),
+      );
+      return;
+    }
 
-  const updateSession = (id: string, nextMessages: ChatMessage[]) => {
+    let importedCount = 0;
-    const now = Date.now();
+    void Promise.all(
-    setSessions((prev) =>
+      legacySessions.map((session) =>
-      prev.map((session) =>
+        importLocalSession({
-        session.id === id
+          legacyLocalId: session.id,
-          ? {
+          title: session.title,
-              ...session,
+          createdAt: session.createdAt,
-              title: titleFromMessages(nextMessages),
+          updatedAt: session.updatedAt,
-              updatedAt: now,
+          messages: session.messages,
-              messages: nextMessages,
+        }),
-            }
-          : session,
       ),
-    );
+    )
-  };
+      .then(() => {
+        importedCount = legacySessions.length;
+        localStorage.setItem(importMarkerKey, "true");
+      })
+      .catch((error) => {
+        console.error(error);
+        toast.error("Lokale Chat-Historie konnte nicht importiert werden.");
+      })
+      .finally(() => {
+        setLegacyImportResult({ key: importMarkerKey, importedCount });
+      });
+  }, [importLocalSession, importMarkerKey, legacyImportComplete]);
+
+  useEffect(() => {
+    if (
+      !legacyImportComplete ||
+      legacyImportedCount > 0 ||
+      sessionsQuery.status === "LoadingFirstPage" ||
+      sessions.length > 0 ||
+      createInitialStartedRef.current
+    ) {
+      return;
+    }
+
+    createInitialStartedRef.current = true;
+    void createSession({ title: "Neuer Chat" })
+      .then((session) => setSelectedSessionId(session.sessionId))
+      .catch((error) => {
+        console.error(error);
+        toast.error("Neuer Chat konnte nicht erstellt werden.");
+      });
+  }, [createSession, legacyImportComplete, legacyImportedCount, sessions.length, sessionsQuery.status]);
 
   const createNewChat = () => {
-    const session = createSession();
-    setSessions((prev) => [session, ...prev]);
-    setActiveSessionId(session.id);
     setDraft("");
+    void createSession({ title: "Neuer Chat" })
+      .then((session) => setSelectedSessionId(session.sessionId))
+      .catch((error) => {
+        console.error(error);
+        toast.error("Neuer Chat konnte nicht erstellt werden.");
+      });
   };
 
   const deleteChat = (id: string) => {
-    const remaining = sessions.filter((session) => session.id !== id);
+    void deleteSession({ sessionId: id as Id<"chatSessions"> })
-    const nextSessions = remaining.length > 0 ? remaining : [createSession()];
+      .then(() => {
-    setSessions(nextSessions);
+        if (id === activeSessionId) {
-    if (id === activeSessionId) setActiveSessionId(nextSessions[0].id);
+          const nextSession = sessions.find((session) => session._id !== id);
+          setSelectedSessionId(nextSession?._id);
+        }
+      })
+      .catch((error) => {
+        console.error(error);
+        toast.error("Chat konnte nicht gelöscht werden.");
+      });
   };
 
-  const historyItems: ChatHistoryItem[] = sessions
+  const historyItems: ChatHistoryItem[] = useMemo(
-    .map((session) => ({
+    () =>
-      id: session.id,
+      sessions.map((session) => ({
-      title: session.title,
+        id: session._id,
-      updatedAt: session.updatedAt,
+        title: session.title,
-      messageCount: session.messages.length,
+        updatedAt: session.updatedAt,
-    }))
+        messageCount: session.messageCount,
-    .sort((a, b) => b.updatedAt - a.updatedAt);
+      })),
+    [sessions],
+  );
 
   const submit = async (event: FormEvent) => {
     event.preventDefault();
     const content = draft.trim();
-    if (!content || isSubmitting) return;
+    if (!content || isSubmitting || !activeSessionId) return;
 
-    const submittedSessionId = activeSessionId;
-    const typedNextMessages: ChatMessage[] = [...messages, { role: "user", content }];
-    updateSession(submittedSessionId, typedNextMessages);
     setDraft("");
     setIsSubmitting(true);
 
     try {
-      const response = await ask({
+      await sendMessage({
-        messages: typedNextMessages.map((message) => ({
+        sessionId: activeSessionId,
-          role: message.role,
+        content,
-          content: message.content,
-        })),
         from,
         to,
         accountId,
         basis: monthBasis,
-      }) as { answer: string; toolTrace?: unknown };
+      });
-
-      updateSession(submittedSessionId, [
-        ...typedNextMessages,
-        {
-          role: "assistant",
-          content: response.answer,
-          toolTrace: normalizeToolTrace(response.toolTrace),
-        },
-      ]);
     } catch (error) {
       console.error(error);
       toast.error("Antwort konnte nicht geladen werden.");
-      updateSession(submittedSessionId, [
-        ...typedNextMessages,
-        {
-          role: "assistant",
-          content: "Ich konnte gerade keine Antwort erzeugen. Bitte später erneut versuchen.",
-        },
-      ]);
     } finally {
       setIsSubmitting(false);
     }
@@ -277,8 +326,8 @@ export function SavingsChatPage() {
     <div className="grid gap-4 xl:grid-cols-[280px_minmax(0,1fr)]">
       <ChatHistory
         items={historyItems}
-        activeId={activeSessionId}
+        activeId={activeSessionId ?? ""}
-        onSelect={setActiveSessionId}
+        onSelect={(id) => setSelectedSessionId(id as Id<"chatSessions">)}
         onCreate={createNewChat}
         onDelete={deleteChat}
       />
@@ -289,82 +338,80 @@ export function SavingsChatPage() {
           <h1 className="text-lg font-semibold">Talk to your savings account</h1>
         </div>
 
-      <Card>
+        <Card>
-        <CardHeader>
+          <CardHeader>
-          <CardTitle>Kontext der Auswertung</CardTitle>
+            <CardTitle>Kontext der Auswertung</CardTitle>
-        </CardHeader>
+          </CardHeader>
-        <CardContent className="space-y-1 text-sm">
+          <CardContent className="space-y-1 text-sm">
-          <p>Zeitraum: {from} bis {to}</p>
+            <p>Zeitraum: {from} bis {to}</p>
-          <p>Basis: {monthBasis === "effective" ? "Effektiv" : "Buchungstag"}</p>
+            <p>Basis: {monthBasis === "effective" ? "Effektiv" : "Buchungstag"}</p>
-          <p>
+            <p>
-            Konto: {context?.accountName ?? "Alle Konten"} (Basis-Saldo{" "}
+              Konto: {context?.accountName ?? "Alle Konten"} (Basis-Saldo{" "}
-            {context ? formatAmount(context.totals.balance) : "—"})
+              {context ? formatAmount(context.totals.balance) : "—"})
-          </p>
+            </p>
-          <p>
+            <p>{context ? getContextSummary() : "Lade Kontext…"}</p>
-            {context ? getContextSummary() : "Lade Kontext…"}
+          </CardContent>
-          </p>
+        </Card>
-        </CardContent>
-      </Card>
 
-      <Card>
+        <Card>
-        <CardContent className="p-4">
+          <CardContent className="p-4">
-          <div className="h-[52vh] overflow-y-auto" ref={listRef}>
+            <div className="h-[52vh] overflow-y-auto" ref={listRef}>
-            <div className="space-y-3">
+              <div className="space-y-3">
-              {messages.map((message, index) => (
+                {displayMessages.map((message) => (
-                <div
+                  <div
-                  key={`${message.role}-${index}`}
+                    key={message._id}
-                  className={`rounded-lg border p-3 ${
+                    className={`rounded-lg border p-3 ${
-                    message.role === "user" ? "bg-muted/50" : "bg-background"
+                      message.role === "user" ? "bg-muted/50" : "bg-background"
-                  }`}
+                    }`}
-                >
+                  >
-                  <p className="text-xs uppercase text-muted-foreground">{message.role}</p>
+                    <p className="text-xs uppercase text-muted-foreground">{message.role}</p>
-                  <p className="whitespace-pre-wrap text-sm">{message.content}</p>
+                    <p className="whitespace-pre-wrap text-sm">{message.content}</p>
-                  {message.role === "assistant" && message.toolTrace && message.toolTrace.length > 0 && (
+                    {message.role === "assistant" && message.toolTrace && message.toolTrace.length > 0 && (
-                    <div className="mt-3 rounded-md border bg-muted/30 p-2">
+                      <div className="mt-3 rounded-md border bg-muted/30 p-2">
-                      <p className="text-xs font-medium text-muted-foreground">
+                        <p className="text-xs font-medium text-muted-foreground">
-                        Verwendete Werkzeuge
+                          Verwendete Werkzeuge
-                      </p>
+                        </p>
-                      <div className="mt-2 space-y-2">
+                        <div className="mt-2 space-y-2">
-                        {message.toolTrace.map((tool, toolIndex) => (
+                          {message.toolTrace.map((tool, toolIndex) => (
-                          <div key={`${tool.name}-${toolIndex}`} className="text-xs">
+                            <div key={`${tool.name}-${toolIndex}`} className="text-xs">
-                            <p className="font-medium">{tool.name}</p>
+                              <p className="font-medium">{tool.name}</p>
-                            <p className="text-muted-foreground">{tool.resultSummary}</p>
+                              <p className="text-muted-foreground">{tool.resultSummary}</p>
-                          </div>
+                            </div>
-                        ))}
+                          ))}
+                        </div>
                       </div>
-                    </div>
+                    )}
-                  )}
+                  </div>
-                </div>
+                ))}
-              ))}
+                {isSubmitting && (
-              {isSubmitting && (
+                  <div className="flex items-center gap-2 text-sm text-muted-foreground">
-                <div className="flex items-center gap-2 text-sm text-muted-foreground">
+                    <Loader2 className="h-4 w-4 animate-spin" />
-                  <Loader2 className="h-4 w-4 animate-spin" />
+                    Denk mit der KI nach…
-                  Denk mit der KI nach…
+                  </div>
-                </div>
+                )}
-              )}
+              </div>
             </div>
-          </div>
+          </CardContent>
-        </CardContent>
+        </Card>
-      </Card>
 
-      <form className="flex gap-2" onSubmit={submit}>
+        <form className="flex gap-2" onSubmit={submit}>
-        <Input
+          <Input
-          value={draft}
+            value={draft}
-          onChange={(event) => setDraft(event.target.value)}
+            onChange={(event) => setDraft(event.target.value)}
-          placeholder="Welche Auswertung soll ich machen?"
+            placeholder={activeSession ? "Welche Auswertung soll ich machen?" : "Chat wird vorbereitet…"}
-          disabled={isSubmitting}
+            disabled={isSubmitting || !activeSessionId}
-          autoFocus
+            autoFocus
-        />
+          />
-        <Button type="submit" disabled={buttonDisabled}>
+          <Button type="submit" disabled={buttonDisabled}>
-          <Send className="h-4 w-4" />
+            <Send className="h-4 w-4" />
-          Senden
+            Senden
-        </Button>
+          </Button>
-      </form>
+        </form>
 
-      <Separator />
+        <Separator />
-      <p className="text-xs text-muted-foreground">
+        <p className="text-xs text-muted-foreground">
-        Antwortmodell: {context ? "Server-seitig bereit" : "…"}
+          Antwortmodell: {context ? "Server-seitig bereit" : "…"}
-      </p>
+        </p>
       </div>
     </div>
   );