Add chat-first onboarding and intelligent context-based paywall

Replaces the hardcoded message limit with a model-driven paywall and
removes registration before the first question:

- Onboarding: the app opens directly into the chat. Dynamic conversation
  starters are served by GET /suggestions (services/api/suggestions.json),
  updatable with a deploy — no app release needed. Guests chat via
  POST /guest/chat, identified by an app-generated device id; sign-in
  moves to the paywall, where a purchase must attach to an account.
- Free experience: the model runs in discovery mode — follow-up
  questions, pattern identification, visible understanding — building an
  analysis without delivering the full solution.
- Intelligent paywall: the model returns structured output (reply +
  analysis_ready). Only when the problem is described, the information is
  sufficient and an action plan is ready does it write a calm transition
  and pause the conversation. Manufactured urgency, emotional pressure,
  fake readiness and mid-answer stops are explicitly forbidden.
- Premium: on unlock the app resends the transcript and the backend
  immediately delivers the full analysis, strategies and exercises, then
  the dialogue continues without restriction.
- The old FREE_MESSAGE_LIMIT becomes MESSAGE_CAP (default 200/30 days),
  kept purely as an abuse backstop — it is not the paywall.
- WelcomeScreen removed; the app is now two views (Chat, Paywall).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0118DaxZR36RpnY524vRqx3z

README.md

@@ -10,7 +10,7 @@ one dark blue-green accent. No animations, no gradients.
 ## System overview
 
 ```
-apps/mobile      Expo / React Native app (three views: Welcome, Chat, Paywall)
+apps/mobile      Expo / React Native app (two views: Chat, Paywall)
 services/api     One Lambda backend (chat, usage, subscription verification)
 infra            AWS CDK stack (the entire cloud environment)
 db/migrations    SQL schema (two tables: users, usage)
@@ -22,16 +22,42 @@ it is not built.
 
 ### Request flow
 
-1. The app signs in via the **Cognito** hosted UI (Apple / Google / email)
-   and receives a JWT.
-2. `POST /chat` goes through **API Gateway** (JWT authorizer) to the single
-   **Lambda**.
-3. The Lambda checks the free-tier quota in **PostgreSQL** (Aurora
-   Serverless v2). Over the limit and not subscribed → HTTP 402 → the app
-   shows the paywall.
-4. Otherwise it calls the **OpenAI Responses API** with the Markdown
-   knowledge base (`services/api/knowledge/`) as system instructions and
-   returns the reply.
+1. The user lands directly in the chat — no registration before the first
+   question. Guests are identified by an app-generated device id
+   (`POST /guest/chat`); dynamic conversation starters come from
+   `GET /suggestions` (both public routes). The suggestions live in
+   `services/api/suggestions.json` and can be updated with a deploy — no
+   app release needed.
+2. Requests go through **API Gateway** to the single **Lambda**; signed-in
+   users use `POST /chat` with a **Cognito** JWT (Apple / Google / email via
+   the hosted UI).
+3. The Lambda calls the **OpenAI Responses API** with the Markdown knowledge
+   base (`services/api/knowledge/`) as system instructions. The model
+   returns structured output: a reply plus an `analysis_ready` flag.
+4. Sign-in happens at the paywall, since a purchase must attach to an
+   account. Usage counters live in **PostgreSQL** (Aurora Serverless v2).
+
+### The intelligent paywall
+
+The paywall is not a hardcoded message count. Free conversations run in
+_discovery mode_: the model asks relevant follow-up questions, names
+patterns, shows understanding, and builds toward an analysis — without
+delivering the full solution. When the problem is described, the information
+is sufficient, and a concrete action plan is ready, the model signals
+`analysis_ready`, writes a calm transition ("…I have a concrete strategy I
+would recommend. Continue with Premium to see the analysis and the
+recommended steps."), and the conversation pauses.
+
+The instructions explicitly forbid manufactured urgency, emotional pressure,
+fake readiness, and stopping mid-answer — Premium should feel like the
+natural continuation of an already valuable dialogue.
+
+On unlock, the app resends the transcript; premium mode then delivers the
+full analysis, recommended strategies and concrete exercises immediately,
+and the dialogue continues without restriction.
+
+A generous `MESSAGE_CAP` (default 200 per 30 days) exists purely as an
+abuse backstop for the free tier — it is not the paywall.
 
 Conversations are never stored server-side; the client holds them in memory
 and sends the running transcript with each request. The database stores the
@@ -51,9 +77,6 @@ provider differs per platform behind one `PaymentProvider` interface:
 
 Plans: Monthly and Yearly. Nothing else.
 
-Free tier: `FREE_MESSAGE_LIMIT` messages (default 50 ≈ 5–10 conversations),
-resetting every `USAGE_RESET_DAYS` days.
-
 ## Getting started
 
 ```sh
@@ -100,12 +123,19 @@ GitHub Actions: `ci.yml` lints, type-checks and tests every PR;
 
 ## Security
 
-- All traffic over HTTPS; every API route requires a Cognito JWT.
+- All traffic over HTTPS. Account routes require a Cognito JWT; the two
+  public routes (`/suggestions`, `/guest/chat`) carry no account data and
+  are bounded by the free-tier message cap.
 - Secrets live in AWS Secrets Manager only — no API keys in the client.
 - The Lambda runs in private subnets; the database is not publicly reachable.
 
 ## Product philosophy
 
+Every free user should leave the app feeling that the system understood
+their situation, that a concrete analysis is ready, and that the next step
+is available in Premium — never that they were held back by an artificial
+interruption.
+
 Every new feature must justify itself. The allowed AWS surface is
 API Gateway, Lambda, Cognito, S3, Secrets Manager and CloudWatch — and V1
 does not even need S3. No Redis, no Kubernetes, no Kafka, no Elasticsearch,

apps/mobile/App.tsx

@@ -1,29 +1,45 @@
-import { useEffect, useState } from 'react';
+import { useState } from 'react';
 import { StatusBar } from 'expo-status-bar';
-import { getAccessToken } from './src/auth/session';
+import type { ChatMessage } from './src/api/client';
 import { ChatScreen } from './src/screens/ChatScreen';
 import { PaywallScreen } from './src/screens/PaywallScreen';
-import { WelcomeScreen } from './src/screens/WelcomeScreen';
-
-type View = 'loading' | 'welcome' | 'chat' | 'paywall';
 
 /**
- * Three views, no navigation library. The backend decides when the paywall
- * appears (HTTP 402 on /chat).
+ * Two views, no navigation library. The user lands directly in the chat —
+ * no registration before the first question. The backend decides the paywall
+ * moment (the analysis is ready); after unlock the conversation continues
+ * with the full analysis delivered immediately.
  */
 export default function App() {
-  const [view, setView] = useState<View>('loading');
-
-  useEffect(() => {
-    getAccessToken().then((token) => setView(token ? 'chat' : 'welcome'));
-  }, []);
+  const [view, setView] = useState<'chat' | 'paywall'>('chat');
+  const [messages, setMessages] = useState<ChatMessage[]>([]);
+  const [paywalled, setPaywalled] = useState(false);
+  const [deliverAnalysis, setDeliverAnalysis] = useState(false);
 
   return (
     <>
       <StatusBar style="dark" />
-      {view === 'welcome' && <WelcomeScreen onSignedIn={() => setView('chat')} />}
-      {view === 'chat' && <ChatScreen onLimitReached={() => setView('paywall')} />}
-      {view === 'paywall' && <PaywallScreen onSubscribed={() => setView('chat')} />}
+      {view === 'chat' && (
+        <ChatScreen
+          messages={messages}
+          setMessages={setMessages}
+          paywalled={paywalled}
+          onPaywallTriggered={() => setPaywalled(true)}
+          onContinueWithPremium={() => setView('paywall')}
+          deliverAnalysis={deliverAnalysis}
+          onAnalysisDelivered={() => setDeliverAnalysis(false)}
+        />
+      )}
+      {view === 'paywall' && (
+        <PaywallScreen
+          onSubscribed={() => {
+            setPaywalled(false);
+            setDeliverAnalysis(true);
+            setView('chat');
+          }}
+          onDismiss={() => setView('chat')}
+        />
+      )}
     </>
   );
 }

apps/mobile/src/api/client.ts

@@ -1,3 +1,5 @@
+import * as Crypto from 'expo-crypto';
+import * as SecureStore from 'expo-secure-store';
 import { appConfig } from '../config';
 import { getAccessToken } from '../auth/session';
 
@@ -16,23 +18,38 @@ export interface ChatMessage {
   content: string;
 }
 
+export interface ChatReply {
+  reply: string;
+  /** True when the backend judged the analysis ready — the paywall moment. */
+  paywall: boolean;
+}
+
 export interface Me {
   subscriptionStatus: 'free' | 'active';
   messagesUsed: number;
-  freeMessageLimit: number;
+  messageCap: number;
 }
 
-async function request<T>(path: string, init?: RequestInit): Promise<T> {
-  const token = await getAccessToken();
-  if (!token) throw new ApiError(401, 'not_signed_in');
+const DEVICE_KEY = 'neurosemantics.device';
 
+/** Stable anonymous id so guests can chat before signing in. */
+async function getDeviceId(): Promise<string> {
+  let id = await SecureStore.getItemAsync(DEVICE_KEY);
+  if (!id) {
+    id = Crypto.randomUUID();
+    await SecureStore.setItemAsync(DEVICE_KEY, id);
+  }
+  return id;
+}
+
+async function request<T>(
+  path: string,
+  init: RequestInit = {},
+  headers: Record<string, string> = {},
+): Promise<T> {
   const response = await fetch(`${appConfig.apiUrl}${path}`, {
     ...init,
-    headers: {
-      Authorization: `Bearer ${token}`,
-      'Content-Type': 'application/json',
-      ...init?.headers,
-    },
+    headers: { 'Content-Type': 'application/json', ...headers },
   });
 
   if (!response.ok) {
@@ -47,21 +64,39 @@ async function request<T>(path: string, init?: RequestInit): Promise<T> {
   return (await response.json()) as T;
 }
 
-export function fetchMe(): Promise<Me> {
-  return request<Me>('/me');
+async function authHeader(): Promise<Record<string, string>> {
+  const token = await getAccessToken();
+  if (!token) throw new ApiError(401, 'not_signed_in');
+  return { Authorization: `Bearer ${token}` };
 }
 
-export function sendChat(messages: ChatMessage[]): Promise<{ reply: string }> {
-  return request<{ reply: string }>('/chat', {
-    method: 'POST',
-    body: JSON.stringify({ messages }),
-  });
+export async function fetchSuggestions(): Promise<string[]> {
+  const data = await request<{ suggestions: string[] }>('/suggestions');
+  return data.suggestions;
 }
 
-export function verifyPurchase(body: {
+/** Signed-in users chat via /chat; guests via /guest/chat with a device id. */
+export async function sendChat(messages: ChatMessage[]): Promise<ChatReply> {
+  const body = { method: 'POST', body: JSON.stringify({ messages }) };
+  const token = await getAccessToken();
+  if (token) {
+    return request<ChatReply>('/chat', body, { Authorization: `Bearer ${token}` });
+  }
+  return request<ChatReply>('/guest/chat', body, { 'X-Device-Id': await getDeviceId() });
+}
+
+export async function fetchMe(): Promise<Me> {
+  return request<Me>('/me', {}, await authHeader());
+}
+
+export async function verifyPurchase(body: {
   platform: 'ios' | 'android';
   productId: string;
   receipt: string;
 }): Promise<{ subscriptionStatus: 'free' | 'active' }> {
-  return request('/subscription/verify', { method: 'POST', body: JSON.stringify(body) });
+  return request(
+    '/subscription/verify',
+    { method: 'POST', body: JSON.stringify(body) },
+    await authHeader(),
+  );
 }

apps/mobile/src/screens/ChatScreen.tsx

@@ -1,4 +1,4 @@
-import { useRef, useState } from 'react';
+import { useEffect, useRef, useState } from 'react';
 import {
   FlatList,
   KeyboardAvoidingView,
@@ -9,54 +9,104 @@ import {
   TextInput,
   View,
 } from 'react-native';
-import { ApiError, sendChat, type ChatMessage } from '../api/client';
+import { fetchSuggestions, sendChat, type ChatMessage } from '../api/client';
 import { colors, spacing, type } from '../theme';
 
 interface Props {
-  onLimitReached: () => void;
+  messages: ChatMessage[];
+  setMessages: (messages: ChatMessage[]) => void;
+  /** The analysis is ready behind Premium; input is replaced by the unlock button. */
+  paywalled: boolean;
+  onPaywallTriggered: () => void;
+  onContinueWithPremium: () => void;
+  /** Set right after unlock: fetch the promised analysis automatically. */
+  deliverAnalysis: boolean;
+  onAnalysisDelivered: () => void;
 }
 
+const SUGGESTIONS_SHOWN = 4;
+
 /**
  * The whole product: one heading, the conversation, a text field and send.
- * Conversations live in memory only — nothing is stored.
+ * The user lands here directly — no registration before the first question.
+ * Conversations live in memory only; nothing is stored.
  */
-export function ChatScreen({ onLimitReached }: Props) {
-  const [messages, setMessages] = useState<ChatMessage[]>([]);
+export function ChatScreen({
+  messages,
+  setMessages,
+  paywalled,
+  onPaywallTriggered,
+  onContinueWithPremium,
+  deliverAnalysis,
+  onAnalysisDelivered,
+}: Props) {
+  const [suggestions, setSuggestions] = useState<string[]>([]);
   const [draft, setDraft] = useState('');
   const [busy, setBusy] = useState(false);
   const [error, setError] = useState<string | null>(null);
   const listRef = useRef<FlatList<ChatMessage>>(null);
 
-  async function send() {
-    const content = draft.trim();
-    if (!content || busy) return;
-    const next: ChatMessage[] = [...messages, { role: 'user', content }];
+  useEffect(() => {
+    fetchSuggestions()
+      .then((all) =>
+        setSuggestions([...all].sort(() => Math.random() - 0.5).slice(0, SUGGESTIONS_SHOWN)),
+      )
+      .catch(() => setSuggestions([]));
+  }, []);
+
+  // After unlocking Premium the transcript ends with the assistant's
+  // transition message; resend it so the backend delivers the full analysis.
+  useEffect(() => {
+    if (!deliverAnalysis || busy) return;
+    setBusy(true);
+    setError(null);
+    sendChat(messages)
+      .then(({ reply }) => {
+        setMessages([...messages, { role: 'assistant', content: reply }]);
+        onAnalysisDelivered();
+      })
+      .catch(() => setError('Something went wrong. Please try again.'))
+      .finally(() => setBusy(false));
+  }, [deliverAnalysis]);
+
+  async function send(content: string) {
+    const trimmed = content.trim();
+    if (!trimmed || busy || paywalled) return;
+    const next: ChatMessage[] = [...messages, { role: 'user', content: trimmed }];
     setMessages(next);
     setDraft('');
     setBusy(true);
     setError(null);
     try {
-      const { reply } = await sendChat(next);
+      const { reply, paywall } = await sendChat(next);
       setMessages([...next, { role: 'assistant', content: reply }]);
-    } catch (e) {
-      if (e instanceof ApiError && e.status === 402) {
-        onLimitReached();
-      } else {
-        setError('Something went wrong. Please try again.');
-        setMessages(messages);
-        setDraft(content);
-      }
+      if (paywall) onPaywallTriggered();
+    } catch {
+      setError('Something went wrong. Please try again.');
+      setMessages(messages);
+      setDraft(trimmed);
     } finally {
       setBusy(false);
     }
   }
 
+  const showSuggestions = messages.length === 0 && suggestions.length > 0;
+
   return (
     <KeyboardAvoidingView
       style={styles.container}
       behavior={Platform.OS === 'ios' ? 'padding' : undefined}
     >
       <Text style={styles.heading}>NeuroSemantics AI</Text>
+      {showSuggestions ? (
+        <View style={styles.suggestions}>
+          {suggestions.map((s) => (
+            <Pressable key={s} style={styles.suggestion} onPress={() => send(s)} disabled={busy}>
+              <Text style={styles.suggestionText}>{s}</Text>
+            </Pressable>
+          ))}
+        </View>
+      ) : null}
       <FlatList
         ref={listRef}
         style={styles.list}
@@ -74,24 +124,32 @@ export function ChatScreen({ onLimitReached }: Props) {
         )}
       />
       {error ? <Text style={styles.error}>{error}</Text> : null}
-      <View style={styles.inputRow}>
-        <TextInput
-          style={styles.input}
-          value={draft}
-          onChangeText={setDraft}
-          placeholder="Write a message"
-          placeholderTextColor={colors.textMuted}
-          multiline
-          editable={!busy}
-        />
-        <Pressable
-          style={[styles.send, (!draft.trim() || busy) && styles.sendDisabled]}
-          onPress={send}
-          disabled={!draft.trim() || busy}
-        >
-          <Text style={styles.sendText}>{busy ? '…' : 'Send'}</Text>
-        </Pressable>
-      </View>
+      {paywalled ? (
+        <View style={styles.inputRow}>
+          <Pressable style={styles.unlock} onPress={onContinueWithPremium}>
+            <Text style={styles.unlockText}>Continue with Premium</Text>
+          </Pressable>
+        </View>
+      ) : (
+        <View style={styles.inputRow}>
+          <TextInput
+            style={styles.input}
+            value={draft}
+            onChangeText={setDraft}
+            placeholder="Write a message"
+            placeholderTextColor={colors.textMuted}
+            multiline
+            editable={!busy}
+          />
+          <Pressable
+            style={[styles.send, (!draft.trim() || busy) && styles.sendDisabled]}
+            onPress={() => send(draft)}
+            disabled={!draft.trim() || busy}
+          >
+            <Text style={styles.sendText}>{busy ? '…' : 'Send'}</Text>
+          </Pressable>
+        </View>
+      )}
     </KeyboardAvoidingView>
   );
 }
@@ -104,9 +162,19 @@ const styles = StyleSheet.create({
     paddingTop: spacing.xxl,
     paddingBottom: spacing.m,
   },
+  suggestions: { paddingHorizontal: spacing.l, gap: spacing.s, marginBottom: spacing.m },
+  suggestion: {
+    backgroundColor: colors.surface,
+    borderColor: colors.border,
+    borderWidth: 1,
+    borderRadius: 10,
+    paddingVertical: spacing.s + 2,
+    paddingHorizontal: spacing.m,
+  },
+  suggestionText: { ...type.body, color: colors.accent },
   list: { flex: 1 },
   listContent: { paddingHorizontal: spacing.l, paddingBottom: spacing.m, gap: spacing.s },
-  empty: { ...type.body, color: colors.textMuted, textAlign: 'center', marginTop: spacing.xxl },
+  empty: { ...type.body, color: colors.textMuted, textAlign: 'center', marginTop: spacing.xl },
   message: { maxWidth: '85%', borderRadius: 12, padding: spacing.m },
   user: { alignSelf: 'flex-end', backgroundColor: colors.accent },
   assistant: {
@@ -144,4 +212,12 @@ const styles = StyleSheet.create({
   },
   sendDisabled: { opacity: 0.4 },
   sendText: { ...type.heading, color: colors.accentText },
+  unlock: {
+    flex: 1,
+    backgroundColor: colors.accent,
+    borderRadius: 12,
+    paddingVertical: spacing.m,
+    alignItems: 'center',
+  },
+  unlockText: { ...type.heading, color: colors.accentText },
 });

apps/mobile/src/screens/PaywallScreen.tsx

@@ -1,16 +1,40 @@
-import { useState } from 'react';
+import { useEffect, useState } from 'react';
 import { Pressable, StyleSheet, Text, View } from 'react-native';
+import { getAccessToken, signIn, type Provider } from '../auth/session';
 import { purchase, restore, type Plan } from '../purchases';
 import { colors, spacing, type } from '../theme';
 
 interface Props {
   onSubscribed: () => void;
+  onDismiss: () => void;
 }
 
-export function PaywallScreen({ onSubscribed }: Props) {
+/**
+ * Shown when the backend has a complete analysis ready. Guests sign in
+ * first (purchases must attach to an account), then choose a plan.
+ */
+export function PaywallScreen({ onSubscribed, onDismiss }: Props) {
+  const [signedIn, setSignedIn] = useState<boolean | null>(null);
   const [busy, setBusy] = useState(false);
   const [error, setError] = useState<string | null>(null);
 
+  useEffect(() => {
+    getAccessToken().then((token) => setSignedIn(token !== null));
+  }, []);
+
+  async function handleSignIn(provider: Provider) {
+    setBusy(true);
+    setError(null);
+    try {
+      await signIn(provider);
+      setSignedIn(true);
+    } catch {
+      setError('Sign-in did not complete. Please try again.');
+    } finally {
+      setBusy(false);
+    }
+  }
+
   async function run(action: () => Promise<'free' | 'active'>) {
     setBusy(true);
     setError(null);
@@ -35,20 +59,52 @@ export function PaywallScreen({ onSubscribed }: Props) {
       <View style={styles.top}>
         <Text style={styles.title}>Continue your journey</Text>
         <Text style={styles.subtitle}>
-          You have used your free conversations. Subscribe to continue.
+          Your analysis and recommended steps are ready. Premium unlocks them and lets the
+          conversation continue without limits.
         </Text>
       </View>
       <View style={styles.actions}>
-        <Pressable style={styles.primaryButton} onPress={() => buy('monthly')} disabled={busy}>
-          <Text style={styles.primaryButtonText}>Monthly</Text>
-        </Pressable>
-        <Pressable style={styles.primaryButton} onPress={() => buy('yearly')} disabled={busy}>
-          <Text style={styles.primaryButtonText}>Yearly</Text>
-        </Pressable>
-        <Pressable style={styles.restore} onPress={() => run(restore)} disabled={busy}>
-          <Text style={styles.restoreText}>Restore Purchase</Text>
-        </Pressable>
+        {signedIn === false ? (
+          <>
+            <Pressable
+              style={styles.primaryButton}
+              onPress={() => handleSignIn('apple')}
+              disabled={busy}
+            >
+              <Text style={styles.primaryButtonText}>Continue with Apple</Text>
+            </Pressable>
+            <Pressable
+              style={styles.secondaryButton}
+              onPress={() => handleSignIn('google')}
+              disabled={busy}
+            >
+              <Text style={styles.secondaryButtonText}>Continue with Google</Text>
+            </Pressable>
+            <Pressable
+              style={styles.secondaryButton}
+              onPress={() => handleSignIn('email')}
+              disabled={busy}
+            >
+              <Text style={styles.secondaryButtonText}>Continue with Email</Text>
+            </Pressable>
+          </>
+        ) : signedIn === true ? (
+          <>
+            <Pressable style={styles.primaryButton} onPress={() => buy('monthly')} disabled={busy}>
+              <Text style={styles.primaryButtonText}>Monthly</Text>
+            </Pressable>
+            <Pressable style={styles.primaryButton} onPress={() => buy('yearly')} disabled={busy}>
+              <Text style={styles.primaryButtonText}>Yearly</Text>
+            </Pressable>
+            <Pressable style={styles.textButton} onPress={() => run(restore)} disabled={busy}>
+              <Text style={styles.textButtonText}>Restore Purchase</Text>
+            </Pressable>
+          </>
+        ) : null}
         {error ? <Text style={styles.error}>{error}</Text> : null}
+        <Pressable style={styles.textButton} onPress={onDismiss} disabled={busy}>
+          <Text style={styles.dismissText}>Not now</Text>
+        </Pressable>
       </View>
     </View>
   );
@@ -77,7 +133,17 @@ const styles = StyleSheet.create({
     alignItems: 'center',
   },
   primaryButtonText: { ...type.heading, color: colors.accentText },
-  restore: { alignItems: 'center', paddingVertical: spacing.m },
-  restoreText: { ...type.body, color: colors.accent },
+  secondaryButton: {
+    backgroundColor: colors.surface,
+    borderColor: colors.border,
+    borderWidth: 1,
+    paddingVertical: spacing.m,
+    borderRadius: 10,
+    alignItems: 'center',
+  },
+  secondaryButtonText: { ...type.heading },
+  textButton: { alignItems: 'center', paddingVertical: spacing.m },
+  textButtonText: { ...type.body, color: colors.accent },
+  dismissText: { ...type.caption },
   error: { ...type.caption, color: '#8A3B2E', textAlign: 'center' },
 });

apps/mobile/src/screens/WelcomeScreen.tsx

@@ -1,98 +0,0 @@
-import { useState } from 'react';
-import { Pressable, StyleSheet, Text, View } from 'react-native';
-import { signIn, type Provider } from '../auth/session';
-import { colors, spacing, type } from '../theme';
-
-interface Props {
-  onSignedIn: () => void;
-}
-
-export function WelcomeScreen({ onSignedIn }: Props) {
-  const [busy, setBusy] = useState(false);
-  const [error, setError] = useState<string | null>(null);
-
-  async function handleSignIn(provider: Provider) {
-    setBusy(true);
-    setError(null);
-    try {
-      await signIn(provider);
-      onSignedIn();
-    } catch {
-      setError('Sign-in did not complete. Please try again.');
-    } finally {
-      setBusy(false);
-    }
-  }
-
-  return (
-    <View style={styles.container}>
-      <View style={styles.top}>
-        <Text style={styles.title}>NeuroSemantics AI</Text>
-        <Text style={styles.subtitle}>
-          A quiet conversation partner for neurosemantics and NLP.
-        </Text>
-      </View>
-      <View style={styles.actions}>
-        <Pressable
-          style={styles.primaryButton}
-          onPress={() => handleSignIn('apple')}
-          disabled={busy}
-        >
-          <Text style={styles.primaryButtonText}>Continue with Apple</Text>
-        </Pressable>
-        <Pressable
-          style={styles.secondaryButton}
-          onPress={() => handleSignIn('google')}
-          disabled={busy}
-        >
-          <Text style={styles.secondaryButtonText}>Continue with Google</Text>
-        </Pressable>
-        <Pressable
-          style={styles.secondaryButton}
-          onPress={() => handleSignIn('email')}
-          disabled={busy}
-        >
-          <Text style={styles.secondaryButtonText}>Continue with Email</Text>
-        </Pressable>
-        {error ? <Text style={styles.error}>{error}</Text> : null}
-        <Text style={styles.footnote}>Start free. No card required.</Text>
-      </View>
-    </View>
-  );
-}
-
-const styles = StyleSheet.create({
-  container: {
-    flex: 1,
-    backgroundColor: colors.background,
-    paddingHorizontal: spacing.l,
-    justifyContent: 'space-between',
-  },
-  top: { marginTop: spacing.xxl * 2 },
-  title: { ...type.title, textAlign: 'center' },
-  subtitle: {
-    ...type.body,
-    color: colors.textMuted,
-    textAlign: 'center',
-    marginTop: spacing.m,
-  },
-  actions: { marginBottom: spacing.xxl, gap: spacing.s },
-  primaryButton: {
-    backgroundColor: colors.accent,
-    paddingVertical: spacing.m,
-    borderRadius: 10,
-    alignItems: 'center',
-  },
-  primaryButtonText: { ...type.heading, color: colors.accentText },
-  secondaryButton: {
-    backgroundColor: colors.surface,
-    borderColor: colors.border,
-    borderWidth: 1,
-    paddingVertical: spacing.m,
-    borderRadius: 10,
-    alignItems: 'center',
-  },
-  secondaryButtonText: { ...type.heading },
-  error: { ...type.caption, color: '#8A3B2E', textAlign: 'center', marginTop: spacing.s },
-  footnote: { ...type.caption, textAlign: 'center', marginTop: spacing.m },
-});

infra/lib/neurosemantics-stack.ts

@@ -1,5 +1,5 @@
 import { CfnOutput, Duration, RemovalPolicy, Stack, type StackProps } from 'aws-cdk-lib';
-import { HttpApi, HttpMethod } from 'aws-cdk-lib/aws-apigatewayv2';
+import { HttpApi, HttpMethod, HttpNoneAuthorizer } from 'aws-cdk-lib/aws-apigatewayv2';
 import { HttpJwtAuthorizer } from 'aws-cdk-lib/aws-apigatewayv2-authorizers';
 import { HttpLambdaIntegration } from 'aws-cdk-lib/aws-apigatewayv2-integrations';
 import * as cognito from 'aws-cdk-lib/aws-cognito';
@@ -141,7 +141,7 @@ export class NeuroSemanticsStack extends Stack {
         DB_SECRET_ARN: db.secret?.secretArn ?? '',
         DB_NAME,
         KNOWLEDGE_DIR: 'knowledge',
-        FREE_MESSAGE_LIMIT: '50',
+        MESSAGE_CAP: '200',
         USAGE_RESET_DAYS: '30',
       },
     });
@@ -161,6 +161,21 @@ export class NeuroSemanticsStack extends Stack {
     api.addRoutes({ path: '/chat', methods: [HttpMethod.POST], integration });
     api.addRoutes({ path: '/subscription/verify', methods: [HttpMethod.POST], integration });
 
+    // Public routes: the user meets the chat before any registration.
+    const publicAuthorizer = new HttpNoneAuthorizer();
+    api.addRoutes({
+      path: '/suggestions',
+      methods: [HttpMethod.GET],
+      integration,
+      authorizer: publicAuthorizer,
+    });
+    api.addRoutes({
+      path: '/guest/chat',
+      methods: [HttpMethod.POST],
+      integration,
+      authorizer: publicAuthorizer,
+    });
+
     new CfnOutput(this, 'ApiUrl', { value: api.apiEndpoint });
     new CfnOutput(this, 'UserPoolId', { value: userPool.userPoolId });
     new CfnOutput(this, 'UserPoolClientId', { value: userPoolClient.userPoolClientId });

services/api/src/chat.ts

@@ -7,6 +7,14 @@ export interface ChatMessage {
   content: string;
 }
 
+export type ChatMode = 'free' | 'premium';
+
+export interface ChatResult {
+  reply: string;
+  /** Free mode only: the model judges a complete analysis is ready to present. */
+  analysisReady: boolean;
+}
+
 const BASE_INSTRUCTIONS = `You are NeuroSemantics AI — a calm, precise conversation partner
 specialized in neurosemantics and NLP (Neuro-Linguistic Programming).
 
@@ -19,16 +27,74 @@ Principles:
   distress or a medical condition, recommend seeking professional help.
 - Answer in the language the user writes in.`;
 
+const FREE_INSTRUCTIONS = `# Conversation mode: free tier (discovery)
+
+Work in discovery mode. In every reply you should:
+- ask relevant follow-up questions (one at a time),
+- identify and name patterns you notice,
+- show genuine understanding of the user's situation,
+- build toward a complete analysis.
+
+Do not yet present the full analysis, the recommended strategy, or concrete
+exercises.
+
+Set "analysis_ready" to true ONLY when all of the following are genuinely met:
+- the user has described their problem,
+- you have enough information to give a concrete, personal recommendation,
+- a specific action plan is ready to present.
+
+When analysis_ready is true, the reply must be a calm, natural transition —
+not an interruption mid-answer. Summarize at a high level what you have
+understood and that a concrete strategy is ready. Example of tone:
+"I think I'm starting to understand what lies behind this situation, and I
+can see some clear communication patterns. I also have a concrete strategy
+I would recommend for your specific situation. Continue with Premium to see
+the analysis and the recommended steps."
+
+Never:
+- manufacture urgency or emotional pressure to drive a purchase,
+- claim readiness or insight you do not have,
+- stop in the middle of answering a direct question,
+- mention Premium in any other situation.
+
+Otherwise, set analysis_ready to false.`;
+
+const PREMIUM_INSTRUCTIONS = `# Conversation mode: premium
+
+The user has full access. Deliver complete value:
+- when your analysis is ready, present it in full: the analysis, recommended
+  strategies, and concrete exercises,
+- if the conversation ends with your own message announcing that an analysis
+  is ready, the user has just unlocked Premium — deliver the full analysis
+  and the recommended steps now, without being asked again,
+- continue the dialogue without restriction.
+
+Always set "analysis_ready" to false; it is not used in this mode.`;
+
+const RESPONSE_SCHEMA = {
+  type: 'object',
+  properties: {
+    reply: { type: 'string' },
+    analysis_ready: { type: 'boolean' },
+  },
+  required: ['reply', 'analysis_ready'],
+  additionalProperties: false,
+} as const;
+
 /**
  * Calls the OpenAI Responses API with the knowledge base as system
  * instructions and the conversation as input. Conversations are held by the
  * client and passed through — nothing is persisted server-side.
+ *
+ * The model returns structured output so the backend — not a hardcoded
+ * message count — decides when the paywall moment has arrived.
  */
-export async function generateReply(messages: ChatMessage[]): Promise<string> {
+export async function generateReply(messages: ChatMessage[], mode: ChatMode): Promise<ChatResult> {
   const appSecret = await getSecret(config.appSecretArn);
   const apiKey = appSecret.OPENAI_API_KEY;
   if (!apiKey) throw new Error('OPENAI_API_KEY missing from application secret');
 
+  const modeInstructions = mode === 'premium' ? PREMIUM_INSTRUCTIONS : FREE_INSTRUCTIONS;
   const response = await fetch('https://api.openai.com/v1/responses', {
     method: 'POST',
     headers: {
@@ -37,8 +103,16 @@ export async function generateReply(messages: ChatMessage[]): Promise<string> {
     },
     body: JSON.stringify({
       model: config.openAiModel,
-      instructions: `${BASE_INSTRUCTIONS}\n\n# Knowledge base\n\n${loadKnowledgeBase()}`,
+      instructions: `${BASE_INSTRUCTIONS}\n\n${modeInstructions}\n\n# Knowledge base\n\n${loadKnowledgeBase()}`,
       input: messages.map((m) => ({ role: m.role, content: m.content })),
+      text: {
+        format: {
+          type: 'json_schema',
+          name: 'chat_turn',
+          strict: true,
+          schema: RESPONSE_SCHEMA,
+        },
+      },
     }),
   });
 
@@ -56,7 +130,11 @@ export async function generateReply(messages: ChatMessage[]): Promise<string> {
     .filter((part) => part.type === 'output_text')
     .map((part) => part.text ?? '')
     .join('');
-
   if (!text) throw new Error('OpenAI response contained no output text');
-  return text;
+
+  const parsed = JSON.parse(text) as { reply: string; analysis_ready: boolean };
+  return {
+    reply: parsed.reply,
+    analysisReady: mode === 'free' && parsed.analysis_ready === true,
+  };
 }

services/api/src/config.ts

@@ -3,8 +3,12 @@
  * variables (set by the CDK stack) — secrets never live here.
  */
 export const config = {
-  /** Number of free messages before the paywall is shown (~5–10 conversations). */
-  freeMessageLimit: Number(process.env.FREE_MESSAGE_LIMIT ?? '50'),
+  /**
+   * Abuse backstop, NOT the paywall. The paywall is intelligent: the model
+   * decides when an analysis is ready. This cap only bounds how many free
+   * messages a single user/device can send per reset window.
+   */
+  messageCap: Number(process.env.MESSAGE_CAP ?? '200'),
   /** Free-tier usage resets after this many days. */
   usageResetDays: Number(process.env.USAGE_RESET_DAYS ?? '30'),
   openAiModel: process.env.OPENAI_MODEL ?? 'gpt-4.1-mini',

services/api/src/handler.ts

@@ -1,10 +1,11 @@
-import type { APIGatewayProxyEventV2WithJWTAuthorizer, APIGatewayProxyResultV2 } from 'aws-lambda';
+import type { APIGatewayProxyEventV2, APIGatewayProxyResultV2 } from 'aws-lambda';
 import { generateReply, type ChatMessage } from './chat.js';
 import { config } from './config.js';
 import { getOrCreateUser, getUsage, incrementUsage, resetUsage, type UserRow } from './db.js';
 import { verifyAndApplyPurchase } from './subscription/index.js';
 import type { VerifyPurchaseRequest } from './subscription/types.js';
 import { canSendMessage, shouldResetUsage } from './usage.js';
+import suggestionsFile from '../suggestions.json';
 
 function json(statusCode: number, body: unknown): APIGatewayProxyResultV2 {
   return {
@@ -20,10 +21,17 @@ interface Identity {
   provider: string;
 }
 
-function identityFromClaims(event: APIGatewayProxyEventV2WithJWTAuthorizer): Identity {
-  const claims = event.requestContext.authorizer.jwt.claims;
+/** Reads the Cognito JWT claims on authorized routes; null on public routes. */
+function identityFromEvent(event: APIGatewayProxyEventV2): Identity | null {
+  const authorizer = (
+    event.requestContext as {
+      authorizer?: { jwt?: { claims?: Record<string, unknown> } };
+    }
+  ).authorizer;
+  const claims = authorizer?.jwt?.claims;
+  if (!claims) return null;
   const sub = String(claims.sub ?? '');
-  if (!sub) throw new Error('JWT is missing a sub claim');
+  if (!sub) return null;
   const email = String(claims.email ?? '');
   // Cognito sets an `identities` claim for federated sign-ins (Apple/Google).
   const identities = String(claims.identities ?? '');
@@ -49,29 +57,43 @@ async function handleMe(user: UserRow): Promise<APIGatewayProxyResultV2> {
   return json(200, {
     subscriptionStatus: user.subscription_status,
     messagesUsed: usage.messages_used,
-    freeMessageLimit: config.freeMessageLimit,
+    messageCap: config.messageCap,
   });
 }
 
+/**
+ * The paywall is intelligent: no hardcoded message count. In free mode the
+ * model works in discovery (follow-up questions, patterns, understanding)
+ * and signals `analysisReady` when a concrete, valuable answer could be
+ * delivered — that is the paywall moment, returned as `paywall: true`.
+ * Premium mode delivers the full analysis, including immediately after
+ * unlock (the transcript then ends with the assistant's transition message).
+ */
 async function handleChat(
   user: UserRow,
   body: string | undefined,
 ): Promise<APIGatewayProxyResultV2> {
+  const premium = user.subscription_status === 'active';
   const parsed = body ? (JSON.parse(body) as { messages?: ChatMessage[] }) : {};
   const messages = parsed.messages ?? [];
   const last = messages[messages.length - 1];
-  if (!last || last.role !== 'user' || typeof last.content !== 'string' || !last.content.trim()) {
+  const validLast =
+    last &&
+    typeof last.content === 'string' &&
+    last.content.trim() &&
+    (last.role === 'user' || (premium && last.role === 'assistant'));
+  if (!validLast) {
     return json(400, { error: 'messages must end with a non-empty user message' });
   }
 
   const usage = await currentUsage(user);
-  if (!canSendMessage(usage.messages_used, user.subscription_status, config.freeMessageLimit)) {
-    return json(402, { error: 'free_limit_reached' });
+  if (!canSendMessage(usage.messages_used, user.subscription_status, config.messageCap)) {
+    return json(402, { error: 'message_cap_reached' });
   }
 
-  const reply = await generateReply(messages);
+  const result = await generateReply(messages, premium ? 'premium' : 'free');
   await incrementUsage(user.id);
-  return json(200, { reply });
+  return json(200, { reply: result.reply, paywall: result.analysisReady });
 }
 
 async function handleVerifyPurchase(
@@ -90,14 +112,33 @@ async function handleVerifyPurchase(
   return json(200, { subscriptionStatus: status });
 }
 
-export async function handler(
-  event: APIGatewayProxyEventV2WithJWTAuthorizer,
-): Promise<APIGatewayProxyResultV2> {
+/** Guests chat before signing in, identified by an app-generated device id. */
+async function handleGuestChat(event: APIGatewayProxyEventV2): Promise<APIGatewayProxyResultV2> {
+  const deviceId = event.headers?.['x-device-id'] ?? '';
+  if (!/^[0-9a-fA-F-]{8,64}$/.test(deviceId)) {
+    return json(400, { error: 'a valid X-Device-Id header is required' });
+  }
+  const user = await getOrCreateUser(`guest:${deviceId}`, '', 'guest');
+  return handleChat(user, event.body);
+}
+
+export async function handler(event: APIGatewayProxyEventV2): Promise<APIGatewayProxyResultV2> {
   try {
-    const identity = identityFromClaims(event);
-    const user = await getOrCreateUser(identity.sub, identity.email, identity.provider);
     const route = `${event.requestContext.http.method} ${event.rawPath}`;
 
+    // Public routes (no sign-in before the first question).
+    if (route === 'GET /suggestions') {
+      return json(200, { suggestions: suggestionsFile.suggestions });
+    }
+    if (route === 'POST /guest/chat') {
+      return await handleGuestChat(event);
+    }
+
+    // Authorized routes (Cognito JWT, enforced by API Gateway).
+    const identity = identityFromEvent(event);
+    if (!identity) return json(401, { error: 'unauthorized' });
+    const user = await getOrCreateUser(identity.sub, identity.email, identity.provider);
+
     switch (route) {
       case 'GET /me':
         return await handleMe(user);

services/api/suggestions.json

@@ -0,0 +1,14 @@
+{
+  "suggestions": [
+    "I need support before a difficult conversation.",
+    "Help me prepare for a salary negotiation.",
+    "I'm going on a first date.",
+    "Why do I get stuck in the same conflicts?",
+    "Help me understand my reactions.",
+    "How do I set clearer boundaries?",
+    "I want to become a better communicator.",
+    "Help me prepare for a job interview.",
+    "How do I build better self-confidence?",
+    "Help me make a difficult decision."
+  ]
+}