Phase 9: production hardening

Config via env, abuse/resource limits, and production serving so the app
is safe to expose publicly:

- Fail-fast on missing SECRET_KEY when MULTI_USER=true
- quickjs per-execution time/memory limits (while(true) can't hang server)
- Per-user/per-IP rate limiting on turn/script/auth endpoints
- Request body size limit + per-user row caps
- Security headers (CSP, X-Frame-Options, nosniff, referrer-policy) incl. SSE
- Debug router 403 and /docs disabled in multi-user mode
- DATABASE_URL support (defaults to Neon Postgres) alongside SQLite
- Documented all env vars in backend/.env.example

Verified locally via uvicorn (MULTI_USER=1, SQLite); see plan/09-phase-hardening.md.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017e6tQuojBLYPetUfmhit4X

Dockerfile

@@ -33,4 +33,9 @@ VOLUME /data
 
 EXPOSE 8000
 WORKDIR /app/backend
-CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000"]
+# --proxy-headers: behind a reverse proxy (any hosted deploy), trust
+# X-Forwarded-For so per-IP rate limits key on the client, not the proxy.
+# Single worker on purpose: the turn lock, rate limiter, and debug log are
+# in-process state.
+CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000", \
+     "--proxy-headers", "--forwarded-allow-ips", "*"]

backend/.env.example

@@ -9,6 +9,22 @@
 # Docker compose sets this to /data/data.db (a named volume).
 AIDND_DB_PATH=
 
+# ---------------------------------------------------------------------------
+# Phase 9 — production hardening
+# ---------------------------------------------------------------------------
+
+# Switch from SQLite to a server database (hosted deploys use Neon Postgres).
+# Any SQLAlchemy URL; postgres:// and postgresql:// schemes are rewritten to
+# the psycopg3 driver automatically. The platform-conventional DATABASE_URL
+# is honored too (AIDND_DATABASE_URL wins if both are set). Unset = SQLite.
+AIDND_DATABASE_URL=
+
+# Comma-separated list of allowed CORS origins. Only needed when the frontend
+# is served from a different origin than the API; the production build is
+# served same-origin by FastAPI, so hosted deploys can leave this unset.
+# Default: http://localhost:5173,http://127.0.0.1:5173 (the Vite dev server).
+AIDND_CORS_ORIGINS=
+
 # ---------------------------------------------------------------------------
 # Phase 8 — optional accounts & multi-user (all optional; defaults keep the
 # app in frictionless single-user "local mode")
@@ -19,12 +35,17 @@ AIDND_DB_PATH=
 AIDND_MULTI_USER=
 
 # Secret for signing session cookies and encrypting stored API keys at rest.
-# If unset, one is auto-generated into `secret.key` next to the database
-# (fine for local/docker-volume runs). Set it explicitly on hosted deploys so
-# sessions survive redeploys when the disk is ephemeral or replaced.
+# If unset in local mode, one is auto-generated into `secret.key` next to the
+# database (fine for local/docker-volume runs). REQUIRED when
+# AIDND_MULTI_USER is on — the app refuses to start without it, because a
+# regenerated secret on an ephemeral hosted filesystem would log out every
+# user on each deploy. Generate one:
+#   python -c "import secrets; print(secrets.token_urlsafe(48))"
 AIDND_SECRET_KEY=
 
-# "1" marks session cookies Secure (HTTPS-only). Turn on in production.
+# Session cookie Secure flag (HTTPS-only). Defaults to on when
+# AIDND_MULTI_USER is on, off otherwise — set 0/1 only to override (e.g. 0
+# when testing multi-user mode over plain http on a LAN address).
 AIDND_COOKIE_SECURE=
 
 # --- Shared demo key (BYOK fallback; only active when AIDND_MULTI_USER=1) ---
@@ -41,4 +62,7 @@ AIDND_DEMO_TURNS_PER_DAY=
 
 # The AI endpoint/API key/model are NOT env vars — they are configured at
 # runtime in the app's Settings page and stored (encrypted) in the database.
-# Phase 9 will add: rate limiting and CORS_ORIGINS.
+#
+# Rate limits, request size limits, and per-user row caps are hardcoded with
+# generous values (see backend/app/limits.py) and active only in multi-user
+# mode — local installs are never throttled.

backend/app/auth.py

@@ -16,8 +16,6 @@ whitelist and a per-day turn cap.
 """
 
 import os
-import time
-from collections import defaultdict, deque
 from dataclasses import dataclass
 from datetime import timezone
 
@@ -35,7 +33,15 @@ def _env_flag(name: str) -> bool:
 MULTI_USER = _env_flag("AIDND_MULTI_USER")
 
 SESSION_COOKIE = "aidnd_session"
-COOKIE_SECURE = _env_flag("AIDND_COOKIE_SECURE")  # enable behind HTTPS in prod
+# Secure cookies default on in multi-user (hosted = HTTPS; browsers also
+# accept Secure on http://localhost). AIDND_COOKIE_SECURE=0/1 overrides —
+# e.g. 0 when testing multi-user over plain http on a LAN address.
+_cookie_secure_env = os.environ.get("AIDND_COOKIE_SECURE", "").strip().lower()
+COOKIE_SECURE = (
+    _cookie_secure_env in ("1", "true", "yes", "on")
+    if _cookie_secure_env
+    else MULTI_USER
+)
 COOKIE_MAX_AGE = 60 * 60 * 24 * 365
 
 # ---------- Shared demo key (BYOK fallback) ----------
@@ -151,21 +157,3 @@ def get_current_user(request: Request, db: Session = Depends(get_db)) -> models.
             raise HTTPException(401, "No session. Call GET /api/auth/me first.")
     _touch(user, db)
     return user
-
-
-# ---------- Brute-force limiter for register/login ----------
-
-_ATTEMPT_LIMIT = 10
-_ATTEMPT_WINDOW = 300  # seconds
-_attempts: dict[str, deque] = defaultdict(deque)
-
-
-def rate_limit_auth(request: Request) -> None:
-    ip = request.client.host if request.client else "unknown"
-    now = time.time()
-    window = _attempts[ip]
-    while window and window[0] < now - _ATTEMPT_WINDOW:
-        window.popleft()
-    if len(window) >= _ATTEMPT_LIMIT:
-        raise HTTPException(429, "Too many attempts. Try again in a few minutes.")
-    window.append(now)

backend/app/database.py

@@ -5,28 +5,59 @@ from sqlalchemy import create_engine, event
 from sqlalchemy.orm import DeclarativeBase, sessionmaker
 
 # AIDND_DB_PATH lets deployments (Docker volume, hosted disk) relocate the
-# database; default stays backend/data.db for local runs.
+# SQLite database; default stays backend/data.db for local runs. The parent
+# directory also hosts the auto-generated secret.key (see security.py), so
+# DB_PATH stays defined even when Postgres is in use.
 _env_db_path = os.environ.get("AIDND_DB_PATH")
 DB_PATH = (
     Path(_env_db_path).resolve()
     if _env_db_path
     else Path(__file__).resolve().parent.parent / "data.db"
 )
-DB_PATH.parent.mkdir(parents=True, exist_ok=True)
 
-engine = create_engine(
-    f"sqlite:///{DB_PATH}",
-    connect_args={"check_same_thread": False},
+# AIDND_DATABASE_URL (or the platform-conventional DATABASE_URL) switches the
+# app to a server database — any SQLAlchemy URL works, but Postgres is what
+# hosted deploys use (Phase 9 decision: Neon). Unset = SQLite, as always.
+DATABASE_URL = (
+    os.environ.get("AIDND_DATABASE_URL", "").strip()
+    or os.environ.get("DATABASE_URL", "").strip()
 )
 
 
-@event.listens_for(engine, "connect")
-def _enable_sqlite_foreign_keys(dbapi_connection, _record):
-    # SQLite ships with foreign keys OFF per connection; without this every
-    # ondelete=CASCADE/SET NULL in models.py is silently ignored.
-    cursor = dbapi_connection.cursor()
-    cursor.execute("PRAGMA foreign_keys=ON")
-    cursor.close()
+def _normalize_url(url: str) -> str:
+    """Map the postgres:// / postgresql:// schemes hosts hand out to the
+    psycopg3 driver installed in requirements.txt."""
+    for prefix in ("postgres://", "postgresql://"):
+        if url.startswith(prefix):
+            return "postgresql+psycopg://" + url[len(prefix):]
+    return url
+
+
+if DATABASE_URL:
+    engine = create_engine(
+        _normalize_url(DATABASE_URL),
+        # Serverless Postgres (Neon) suspends idle databases; pre-ping
+        # replaces silently-dead pooled connections instead of erroring.
+        pool_pre_ping=True,
+        # Store/read naive UTC like SQLite does, regardless of server default.
+        connect_args={"options": "-c timezone=UTC"},
+    )
+else:
+    DB_PATH.parent.mkdir(parents=True, exist_ok=True)
+    engine = create_engine(
+        f"sqlite:///{DB_PATH}",
+        connect_args={"check_same_thread": False},
+    )
+
+    @event.listens_for(engine, "connect")
+    def _enable_sqlite_foreign_keys(dbapi_connection, _record):
+        # SQLite ships with foreign keys OFF per connection; without this every
+        # ondelete=CASCADE/SET NULL in models.py is silently ignored.
+        cursor = dbapi_connection.cursor()
+        cursor.execute("PRAGMA foreign_keys=ON")
+        cursor.close()
+
+
 SessionLocal = sessionmaker(bind=engine, autoflush=False, expire_on_commit=False)
 
 

backend/app/limits.py

@@ -0,0 +1,221 @@
+"""Phase 9 — abuse guards for hosted (multi-user) deployments.
+
+Rate limits and row caps are no-ops in local mode: a single local player
+should never be throttled by their own app. Values are hardcoded on purpose —
+generous enough that a legitimate player never notices, tight enough that a
+hostile visitor can't burn the demo key, peg the CPU, or bloat the database.
+"""
+
+import json
+import threading
+import time
+from collections import defaultdict, deque
+
+from fastapi import HTTPException, Request
+from sqlalchemy import func
+from sqlalchemy.orm import Session
+
+from . import auth, models
+
+# ---------- Rate limiting ----------
+# Fixed windows per (scope, caller). In-memory: fine for the single-process
+# deployment this app targets (and the worst case after a restart is a brief
+# extra allowance).
+
+# scope -> (max requests, window seconds)
+RATE_LIMITS: dict[str, tuple[int, int]] = {
+    "turn": (10, 60),             # AI turn generation (demo key also has a daily cap)
+    "script-test": (30, 60),      # sandboxed, but each run costs up to 2s CPU
+    "connection-test": (10, 60),  # outbound HTTP to a user-supplied URL
+    "import": (30, 60),           # large writes
+    "auth": (10, 300),            # register/login attempts, per IP
+    "guest": (30, 300),           # new guest users, per IP (each is a DB row)
+}
+
+_windows: dict[tuple[str, str], deque] = defaultdict(deque)
+_windows_guard = threading.Lock()
+
+
+def _client_ip(request: Request) -> str:
+    return request.client.host if request.client else "unknown"
+
+
+def rate_limit(scope: str, request: Request, user: models.User | None = None) -> None:
+    """429 when the caller exceeds the scope's window. Keyed per user when one
+    is known (accounts survive IP changes), per IP otherwise."""
+    if not auth.MULTI_USER:
+        return
+    limit, window_seconds = RATE_LIMITS[scope]
+    key = (scope, f"u{user.id}" if user else f"ip{_client_ip(request)}")
+    now = time.time()
+    with _windows_guard:
+        window = _windows[key]
+        while window and window[0] < now - window_seconds:
+            window.popleft()
+        if len(window) >= limit:
+            raise HTTPException(
+                429, "You're doing that too fast — wait a minute and try again."
+            )
+        window.append(now)
+        if len(_windows) > 10_000:
+            _prune(now)
+
+
+def _prune(now: float) -> None:
+    """Drop callers whose whole window has expired (call with guard held) so
+    the per-IP dict can't grow without bound."""
+    longest = max(seconds for _, seconds in RATE_LIMITS.values())
+    stale = [key for key, window in _windows.items()
+             if not window or window[-1] < now - longest]
+    for key in stale:
+        del _windows[key]
+
+
+# ---------- Per-user row caps ----------
+
+MAX_ADVENTURES_PER_USER = 100
+MAX_SCENARIOS_PER_USER = 200
+MAX_SCRIPTS_PER_USER = 200
+MAX_STORY_CARDS_PER_OWNER = 200   # per scenario or adventure
+MAX_MEMORIES_PER_ADVENTURE = 1000
+MAX_ACTIONS_PER_ADVENTURE = 5000
+
+
+def check_row_cap(
+    kind: str,
+    db: Session,
+    user: models.User,
+    *,
+    adventure: models.Adventure | None = None,
+    scenario_id: int | None = None,
+    adventure_id: int | None = None,
+) -> None:
+    """409 with a friendly message when creating one more row of `kind` would
+    exceed its cap. Ownership of the passed scenario/adventure has already
+    been checked by the caller."""
+    if not auth.MULTI_USER:
+        return
+    if kind == "adventures":
+        count = _count(db, models.Adventure, models.Adventure.user_id == user.id)
+        cap, subject, hint = (
+            MAX_ADVENTURES_PER_USER, "adventures",
+            "delete one you no longer play to make room",
+        )
+    elif kind == "scenarios":
+        count = _count(db, models.Scenario, models.Scenario.user_id == user.id)
+        cap, subject, hint = (
+            MAX_SCENARIOS_PER_USER, "scenarios", "delete one to make room"
+        )
+    elif kind == "scripts":
+        count = _count(db, models.Script, models.Script.user_id == user.id)
+        cap, subject, hint = (
+            MAX_SCRIPTS_PER_USER, "scripts", "delete one to make room"
+        )
+    elif kind == "story_cards":
+        owner_filter = (
+            models.StoryCard.scenario_id == scenario_id
+            if scenario_id is not None
+            else models.StoryCard.adventure_id == adventure_id
+        )
+        count = _count(db, models.StoryCard, owner_filter)
+        cap, subject, hint = (
+            MAX_STORY_CARDS_PER_OWNER, "story cards here", "delete one to make room"
+        )
+    elif kind == "memories":
+        count = _count(db, models.Memory, models.Memory.adventure_id == adventure.id)
+        cap, subject, hint = (
+            MAX_MEMORIES_PER_ADVENTURE, "memories in this adventure",
+            "delete some to make room",
+        )
+    elif kind == "actions":
+        count = _count(db, models.Action, models.Action.adventure_id == adventure.id)
+        cap, subject, hint = (
+            MAX_ACTIONS_PER_ADVENTURE, "actions in this adventure",
+            "export it and continue in a new adventure",
+        )
+    else:  # pragma: no cover — programming error, not user input
+        raise ValueError(f"Unknown row cap kind: {kind}")
+    if count >= cap:
+        raise HTTPException(409, f"You've reached the limit of {cap} {subject} — {hint}.")
+
+
+def _count(db: Session, model, condition) -> int:
+    return db.query(func.count(model.id)).filter(condition).scalar() or 0
+
+
+_BUNDLE_LIST_CAPS = {
+    "story_cards": MAX_STORY_CARDS_PER_OWNER,
+    "memories": MAX_MEMORIES_PER_ADVENTURE,
+    "actions": MAX_ACTIONS_PER_ADVENTURE,
+}
+
+
+def check_bundle_lists(**lists) -> None:
+    """409 when an import bundle's lists exceed the same caps live creation
+    enforces (kwargs: story_cards=, memories=, actions=)."""
+    if not auth.MULTI_USER:
+        return
+    for name, value in lists.items():
+        cap = _BUNDLE_LIST_CAPS[name]
+        if isinstance(value, list) and len(value) > cap:
+            noun = name.replace("_", " ")
+            raise HTTPException(
+                409, f"This file contains {len(value)} {noun} — the limit is {cap}."
+            )
+
+
+# ---------- Request body size ----------
+# Generous enough for the biggest legitimate payload (an adventure export with
+# thousands of actions), applied in every mode — no honest request comes close.
+
+MAX_BODY_BYTES = 2 * 1024 * 1024
+MAX_IMPORT_BODY_BYTES = 20 * 1024 * 1024
+
+
+class BodySizeLimitMiddleware:
+    """Rejects oversized request bodies by declared Content-Length. Pure ASGI
+    (not BaseHTTPMiddleware) so SSE responses stream through untouched.
+    Chunked uploads without a length are refused — every real client of this
+    API (browser fetch, curl with a file) sends Content-Length."""
+
+    def __init__(self, app):
+        self.app = app
+
+    async def __call__(self, scope, receive, send):
+        if scope["type"] == "http" and scope.get("method") in ("POST", "PUT", "PATCH"):
+            headers = {k.decode("latin-1").lower(): v.decode("latin-1")
+                       for k, v in scope.get("headers", [])}
+            limit = (
+                MAX_IMPORT_BODY_BYTES
+                if scope.get("path", "").endswith("/import")
+                else MAX_BODY_BYTES
+            )
+            length = headers.get("content-length")
+            problem = None
+            if length is None:
+                if "chunked" in headers.get("transfer-encoding", "").lower():
+                    problem = (411, "Content-Length is required.")
+            else:
+                try:
+                    if int(length) > limit:
+                        problem = (
+                            413,
+                            f"Request too large (limit {limit // (1024 * 1024)} MB).",
+                        )
+                except ValueError:
+                    problem = (400, "Invalid Content-Length.")
+            if problem:
+                await _send_json_error(send, *problem)
+                return
+        await self.app(scope, receive, send)
+
+
+async def _send_json_error(send, status: int, detail: str) -> None:
+    body = json.dumps({"detail": detail}).encode()
+    await send({
+        "type": "http.response.start",
+        "status": status,
+        "headers": [(b"content-type", b"application/json"),
+                    (b"content-length", str(len(body)).encode())],
+    })
+    await send({"type": "http.response.body", "body": body})

backend/app/main.py

@@ -1,3 +1,4 @@
+import os
 from pathlib import Path
 
 from fastapi import FastAPI
@@ -5,21 +6,80 @@ from fastapi.middleware.cors import CORSMiddleware
 from fastapi.staticfiles import StaticFiles
 from starlette.exceptions import HTTPException as StarletteHTTPException
 
+from .auth import MULTI_USER
 from .database import engine
+from .limits import BodySizeLimitMiddleware
 from .migrations import bootstrap
 from .routers import adventures, auth, debug, scenarios, scripts, settings, story_cards
 
 bootstrap(engine)
 
-app = FastAPI(title="AI D&D")
+# Production serves the SPA same-origin, so CORS only matters for the Vite dev
+# server; AIDND_CORS_ORIGINS overrides for any other cross-origin setup.
+CORS_ORIGINS = [
+    o.strip()
+    for o in os.environ.get("AIDND_CORS_ORIGINS", "").split(",")
+    if o.strip()
+] or ["http://localhost:5173", "http://127.0.0.1:5173"]
+
+# The interactive API docs stay local-only: in multi-user mode they just hand
+# strangers a map of the API surface.
+app = FastAPI(
+    title="AI D&D",
+    docs_url=None if MULTI_USER else "/docs",
+    redoc_url=None,
+    openapi_url=None if MULTI_USER else "/openapi.json",
+)
 
 app.add_middleware(
     CORSMiddleware,
-    allow_origins=["http://localhost:5173", "http://127.0.0.1:5173"],
+    allow_origins=CORS_ORIGINS,
     allow_methods=["*"],
     allow_headers=["*"],
 )
 
+app.add_middleware(BodySizeLimitMiddleware)
+
+
+class SecurityHeadersMiddleware:
+    """Standard hardening headers on every response. Pure ASGI (wraps `send`)
+    so SSE streams pass through unbuffered. The CSP allows exactly what the
+    SPA uses: same-origin everything, inline styles (React), Google Fonts."""
+
+    _HEADERS = [
+        (b"x-content-type-options", b"nosniff"),
+        (b"referrer-policy", b"same-origin"),
+        (b"x-frame-options", b"DENY"),
+        (
+            b"content-security-policy",
+            b"default-src 'self'; "
+            b"script-src 'self'; "
+            b"style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; "
+            b"font-src https://fonts.gstatic.com; "
+            b"img-src 'self' data:; "
+            b"connect-src 'self'; "
+            b"frame-ancestors 'none'",
+        ),
+    ]
+
+    def __init__(self, app):
+        self.app = app
+
+    async def __call__(self, scope, receive, send):
+        if scope["type"] != "http":
+            return await self.app(scope, receive, send)
+
+        async def send_with_headers(message):
+            if message["type"] == "http.response.start":
+                message.setdefault("headers", [])
+                message["headers"] = list(message["headers"]) + self._HEADERS
+            await send(message)
+
+        await self.app(scope, receive, send_with_headers)
+
+
+app.add_middleware(SecurityHeadersMiddleware)
+
 app.include_router(auth.router)
 app.include_router(scenarios.router)
 app.include_router(adventures.router)

backend/app/migrations.py

@@ -1,14 +1,20 @@
-"""Lightweight versioned schema migrations over SQLite's PRAGMA user_version.
+"""Lightweight versioned schema migrations.
 
 How it works:
 - A fresh database is created by `Base.metadata.create_all()` (always current)
   and stamped with LATEST_VERSION.
 - An existing database runs every migration whose version is greater than its
-  stored user_version, in order, then is stamped.
+  stored version, in order, then is stamped.
+
+The version lives in SQLite's PRAGMA user_version, or a one-row
+`schema_version` table on Postgres (no PRAGMA there).
 
 To change the schema: update models.py (keeps fresh DBs current) AND append a
 (version, sql) pair here (upgrades existing DBs). Keep migrations idempotent
-where cheap (IF NOT EXISTS etc.).
+where cheap (IF NOT EXISTS etc.). Migrations up to 23 predate Postgres support
+and use SQLite-only syntax — that's fine because every Postgres database
+starts fresh (created by create_all, stamped LATEST, never replays them), but
+migrations added from Phase 9 on must run on both dialects.
 """
 
 from sqlalchemy import inspect, text
@@ -70,19 +76,46 @@ MIGRATIONS: list[tuple[int, str]] = [
 LATEST_VERSION = max((v for v, _ in MIGRATIONS), default=1)
 
 
+def _get_version(conn) -> int:
+    if conn.dialect.name == "sqlite":
+        return conn.execute(text("PRAGMA user_version")).scalar() or 1
+    conn.execute(text(
+        "CREATE TABLE IF NOT EXISTS schema_version (version INTEGER NOT NULL)"
+    ))
+    version = conn.execute(text("SELECT version FROM schema_version")).scalar()
+    # A non-fresh database with no stamp can only have been created by an
+    # earlier create_all of this same codebase — i.e. already at LATEST.
+    return version if version is not None else LATEST_VERSION
+
+
+def _set_version(conn, version: int) -> None:
+    if conn.dialect.name == "sqlite":
+        conn.execute(text(f"PRAGMA user_version = {version}"))
+        return
+    conn.execute(text(
+        "CREATE TABLE IF NOT EXISTS schema_version (version INTEGER NOT NULL)"
+    ))
+    if conn.execute(text("SELECT version FROM schema_version")).scalar() is None:
+        conn.execute(
+            text("INSERT INTO schema_version (version) VALUES (:v)"), {"v": version}
+        )
+    else:
+        conn.execute(text("UPDATE schema_version SET version = :v"), {"v": version})
+
+
 def bootstrap(engine: Engine) -> None:
     fresh = not inspect(engine).get_table_names()
     Base.metadata.create_all(bind=engine)
     with engine.begin() as conn:
         if fresh:
-            conn.execute(text(f"PRAGMA user_version = {LATEST_VERSION}"))
+            _set_version(conn, LATEST_VERSION)
             return
-        current = conn.execute(text("PRAGMA user_version")).scalar() or 1
+        current = _get_version(conn)
         for version, sql in MIGRATIONS:
             if version > current:
                 conn.execute(text(sql))
                 current = version
-        conn.execute(text(f"PRAGMA user_version = {current}"))
+        _set_version(conn, current)
         _encrypt_plaintext_api_keys(conn)
 
 

backend/app/routers/adventures.py

@@ -2,12 +2,12 @@ import json
 import re
 import threading
 
-from fastapi import APIRouter, Body, Depends, HTTPException
+from fastapi import APIRouter, Body, Depends, HTTPException, Request
 from fastapi.responses import StreamingResponse
 from sqlalchemy import func
 from sqlalchemy.orm import Session
 
-from .. import auth, memorybank, models, schemas
+from .. import auth, limits, memorybank, models, schemas
 from ..context import build_context
 from ..database import get_db
 from ..providers import OpenAICompatibleProvider, PromptParts, ProviderError
@@ -70,6 +70,7 @@ def create_adventure(
     db: Session = Depends(get_db),
     user: models.User = CurrentUser,
 ):
+    limits.check_row_cap("adventures", db, user)
     scenario = None
     if payload.scenario_id is not None:
         scenario = db.get(models.Scenario, payload.scenario_id)
@@ -207,6 +208,12 @@ def sse(obj: dict) -> str:
     return f"data: {json.dumps(obj)}\n\n"
 
 
+# no-cache defeats any intermediary caching; X-Accel-Buffering makes
+# nginx-style reverse proxies (hosted deploys) flush each event immediately
+# instead of buffering the stream.
+SSE_HEADERS = {"Cache-Control": "no-cache", "X-Accel-Buffering": "no"}
+
+
 def action_json(action: models.Action) -> dict:
     return schemas.ActionOut.model_validate(action).model_dump(mode="json")
 
@@ -363,24 +370,32 @@ async def run_player_turn(
 def create_action(
     adventure_id: int,
     payload: schemas.ActionCreate,
+    request: Request,
     db: Session = Depends(get_db),
     user: models.User = CurrentUser,
 ):
     adventure = get_adventure_or_404(adventure_id, db, user)
+    limits.rate_limit("turn", request, user)
+    limits.check_row_cap("actions", db, user, adventure=adventure)
     check_demo_cap(db, user)
     acquire_turn_lock(adventure_id)
     return StreamingResponse(
         with_turn_lock(adventure_id, run_player_turn(adventure, db, payload, user)),
         media_type="text/event-stream",
+        headers=SSE_HEADERS,
     )
 
 
 @router.post("/{adventure_id}/retry")
 def retry_action(
-    adventure_id: int, db: Session = Depends(get_db), user: models.User = CurrentUser
+    adventure_id: int,
+    request: Request,
+    db: Session = Depends(get_db),
+    user: models.User = CurrentUser,
 ):
     """Delete the last AI action and regenerate from the same input."""
     adventure = get_adventure_or_404(adventure_id, db, user)
+    limits.rate_limit("turn", request, user)
     check_demo_cap(db, user)
     acquire_turn_lock(adventure_id)
     try:
@@ -397,6 +412,7 @@ def retry_action(
             generate_turn(adventure, db, ScriptPipeline(adventure, db), user),
         ),
         media_type="text/event-stream",
+        headers=SSE_HEADERS,
     )
 
 
@@ -472,16 +488,26 @@ def export_adventure(
 
 @router.post("/import", response_model=schemas.AdventureOut, status_code=201)
 def import_adventure(
+    request: Request,
     bundle: dict = Body(...),
     db: Session = Depends(get_db),
     user: models.User = CurrentUser,
 ):
     if bundle.get("format") != "ai-dnd-adventure-v1":
         raise HTTPException(400, "Not an adventure export file (expected format ai-dnd-adventure-v1).")
+    limits.rate_limit("import", request, user)
+    limits.check_row_cap("adventures", db, user)
+    limits.check_bundle_lists(
+        story_cards=bundle.get("storyCards"),
+        memories=bundle.get("memories"),
+        actions=bundle.get("actions"),
+    )
 
+    # Raw-dict import bypasses the schemas — clamp strings headed for VARCHAR
+    # columns (Postgres enforces the widths; see schemas.py).
     adventure = models.Adventure(
         user_id=user.id,
-        title=str(bundle.get("title") or "Imported Adventure"),
+        title=str(bundle.get("title") or "Imported Adventure")[:schemas.NAME_MAX],
         memory=str(bundle.get("memory") or ""),
         authors_note=str(bundle.get("authorsNote") or ""),
         ai_instructions=str(bundle.get("aiInstructions") or ""),
@@ -511,8 +537,8 @@ def import_adventure(
         if isinstance(card, dict):
             db.add(models.StoryCard(
                 adventure_id=adventure.id,
-                type=str(card.get("type") or ""),
-                name=str(card.get("name") or ""),
+                type=str(card.get("type") or "")[:schemas.CARD_TYPE_MAX],
+                name=str(card.get("name") or "")[:schemas.NAME_MAX],
                 keys=str(card.get("keys") or ""),
                 entry=str(card.get("entry") or ""),
                 notes=str(card.get("notes") or ""),
@@ -524,7 +550,7 @@ def import_adventure(
                 adventure_id=adventure.id,
                 position=int(s.get("position", i)),
                 enabled=bool(s.get("enabled", True)),
-                name=str(s.get("name") or "Imported Script"),
+                name=str(s.get("name") or "Imported Script")[:schemas.NAME_MAX],
                 description=str(s.get("description") or ""),
                 library_js=str(s.get("library") or ""),
                 input_js=str(s.get("input") or ""),
@@ -537,7 +563,7 @@ def import_adventure(
             db.add(models.Action(
                 adventure_id=adventure.id,
                 index=int(a.get("index", i)),
-                type=str(a.get("type") or "story"),
+                type=str(a.get("type") or "story")[:20],  # VARCHAR(20)
                 text=str(a["text"]),
                 reasoning=str(a["reasoning"]) if a.get("reasoning") else None,
             ))
@@ -631,6 +657,7 @@ def create_memory(
 ):
     """Manually add a memory; it gets embedded by the next post-turn pass."""
     adventure = get_adventure_or_404(adventure_id, db, user)
+    limits.check_row_cap("memories", db, user, adventure=adventure)
     if not payload.text.strip():
         raise HTTPException(400, "Memory text cannot be empty")
     memory = models.Memory(adventure_id=adventure.id, text=payload.text.strip())

backend/app/routers/auth.py

@@ -3,7 +3,7 @@ import re
 from fastapi import APIRouter, Depends, HTTPException, Request, Response
 from sqlalchemy.orm import Session
 
-from .. import auth, models, schemas, security
+from .. import auth, limits, models, schemas, security
 from ..database import get_db
 from .settings import get_settings
 
@@ -53,6 +53,8 @@ def me(request: Request, response: Response, db: Session = Depends(get_db)):
     else:
         user = auth.resolve_session_user(request, db)
         if user is None:
+            # Each new guest is a database row — cap how fast one IP can mint them.
+            limits.rate_limit("guest", request)
             user = models.User(is_guest=True)
             db.add(user)
             db.commit()
@@ -71,7 +73,7 @@ def register(
     scenario, script and setting they created as a guest is kept."""
     if not auth.MULTI_USER:
         raise HTTPException(400, "Accounts are disabled in local mode.")
-    auth.rate_limit_auth(request)
+    limits.rate_limit("auth", request)
     email = payload.email.strip().lower()
     if not EMAIL_RE.match(email):
         raise HTTPException(422, "Enter a valid email address.")
@@ -99,7 +101,7 @@ def login(
     session is simply abandoned (its data stays under the guest user)."""
     if not auth.MULTI_USER:
         raise HTTPException(400, "Accounts are disabled in local mode.")
-    auth.rate_limit_auth(request)
+    limits.rate_limit("auth", request)
     email = payload.email.strip().lower()
     user = db.query(models.User).filter(models.User.email == email).first()
     if (

backend/app/routers/scenarios.py

@@ -1,8 +1,8 @@
-from fastapi import APIRouter, Body, Depends, HTTPException
+from fastapi import APIRouter, Body, Depends, HTTPException, Request
 from sqlalchemy import or_
 from sqlalchemy.orm import Session
 
-from .. import auth, models, schemas
+from .. import auth, limits, models, schemas
 from ..database import get_db
 
 router = APIRouter(prefix="/api/scenarios", tags=["scenarios"])
@@ -39,6 +39,7 @@ def create_scenario(
     db: Session = Depends(get_db),
     user: models.User = Depends(auth.get_current_user),
 ):
+    limits.check_row_cap("scenarios", db, user)
     scenario = models.Scenario(**payload.model_dump(), user_id=user.id)
     db.add(scenario)
     db.commit()
@@ -141,12 +142,15 @@ _IGNORED_KEYS = {"format", "storyCards", "worldInfo", "worldInformation", "scrip
 
 @router.post("/import", status_code=201)
 def import_scenario(
+    request: Request,
     bundle: dict = Body(...),
     db: Session = Depends(get_db),
     user: models.User = Depends(auth.get_current_user),
 ):
     """Accepts our export format and AI Dungeon scenario exports best-effort;
     reports any keys it didn't understand."""
+    limits.rate_limit("import", request, user)
+    limits.check_row_cap("scenarios", db, user)
     fields: dict = {}
     unmapped: list[str] = []
     for key, value in bundle.items():
@@ -164,6 +168,10 @@ def import_scenario(
     scenario = models.Scenario(**fields, user_id=user.id)
     if not scenario.title:
         scenario.title = "Imported Scenario"
+    # Raw-dict import bypasses the schemas — clamp to VARCHAR widths
+    # (Postgres enforces them; see schemas.py).
+    scenario.title = scenario.title[:schemas.NAME_MAX]
+    scenario.tags = scenario.tags[:schemas.TAGS_MAX]
     db.add(scenario)
     db.flush()
 
@@ -174,14 +182,15 @@ def import_scenario(
         or bundle.get("worldInformation")
         or []
     )
+    limits.check_bundle_lists(story_cards=cards)
     for card in cards:
         if not isinstance(card, dict):
             continue
         db.add(
             models.StoryCard(
                 scenario_id=scenario.id,
-                type=str(card.get("type") or ""),
-                name=str(card.get("name") or card.get("title") or ""),
+                type=str(card.get("type") or "")[:schemas.CARD_TYPE_MAX],
+                name=str(card.get("name") or card.get("title") or "")[:schemas.NAME_MAX],
                 keys=str(card.get("keys") or ""),
                 # AI Dungeon world info uses "value"; story cards use "entry".
                 entry=str(card.get("entry") or card.get("value") or ""),
@@ -194,7 +203,7 @@ def import_scenario(
             continue
         script = models.Script(
             user_id=user.id,
-            name=str(item.get("name") or "Imported Script"),
+            name=str(item.get("name") or "Imported Script")[:schemas.NAME_MAX],
             description=str(item.get("description") or ""),
             library_js=str(item.get("library") or item.get("sharedLibrary") or ""),
             input_js=str(item.get("input") or item.get("onInput") or ""),

backend/app/routers/scripts.py

@@ -1,7 +1,7 @@
-from fastapi import APIRouter, Body, Depends, HTTPException
+from fastapi import APIRouter, Body, Depends, HTTPException, Request
 from sqlalchemy.orm import Session
 
-from .. import auth, models, schemas
+from .. import auth, limits, models, schemas
 from ..database import get_db
 from ..scripting import run_hook
 
@@ -36,6 +36,7 @@ def create_script(
     db: Session = Depends(get_db),
     user: models.User = Depends(auth.get_current_user),
 ):
+    limits.check_row_cap("scripts", db, user)
     script = models.Script(**payload.model_dump(), user_id=user.id)
     db.add(script)
     db.commit()
@@ -79,11 +80,13 @@ def delete_script(
 def test_script(
     script_id: int,
     payload: schemas.ScriptTestRequest,
+    request: Request,
     db: Session = Depends(get_db),
     user: models.User = Depends(auth.get_current_user),
 ):
     """Dry-run one hook against sample text — no AI call, no persistence."""
     script = get_script_or_404(script_id, db, user)
+    limits.rate_limit("script-test", request, user)
     result = run_hook(
         script.library_js,
         getattr(script, HOOK_FIELDS[payload.hook]),
@@ -125,11 +128,14 @@ def export_script(
 
 @router.post("/import", response_model=schemas.ScriptOut, status_code=201)
 def import_script(
+    request: Request,
     bundle: dict = Body(...),
     db: Session = Depends(get_db),
     user: models.User = Depends(auth.get_current_user),
 ):
     """Accepts our export bundle; tolerates *_js key names too."""
+    limits.rate_limit("import", request, user)
+    limits.check_row_cap("scripts", db, user)
     def pick(*keys: str) -> str:
         for key in keys:
             value = bundle.get(key)
@@ -139,7 +145,8 @@ def import_script(
 
     script = models.Script(
         user_id=user.id,
-        name=pick("name") or "Imported Script",
+        # Raw-dict import bypasses the schemas — clamp to the VARCHAR width.
+        name=(pick("name") or "Imported Script")[:schemas.NAME_MAX],
         description=pick("description"),
         library_js=pick("library", "library_js", "sharedLibrary"),
         input_js=pick("input", "input_js", "onInput"),

backend/app/routers/settings.py

@@ -1,8 +1,8 @@
 import httpx
-from fastapi import APIRouter, Depends
+from fastapi import APIRouter, Depends, Request
 from sqlalchemy.orm import Session
 
-from .. import auth, models, schemas, security
+from .. import auth, limits, models, schemas, security
 from ..database import get_db
 
 router = APIRouter(prefix="/api/settings", tags=["settings"])
@@ -64,12 +64,14 @@ def update_settings(
 
 @router.post("/test")
 async def test_connection(
+    request: Request,
     db: Session = Depends(get_db),
     user: models.User = Depends(auth.get_current_user),
 ):
     """Hit the endpoint's /models listing as a cheap connectivity check.
     Tests whatever the turn engine would actually use — including the shared
     demo endpoint when the user has no key of their own."""
+    limits.rate_limit("connection-test", request, user)
     settings = get_settings(db, user)
     cfg = auth.resolve_provider_config(settings)
     url = cfg.endpoint_url.rstrip("/") + "/models"

backend/app/routers/story_cards.py

@@ -1,7 +1,7 @@
 from fastapi import APIRouter, Depends, HTTPException
 from sqlalchemy.orm import Session
 
-from .. import auth, models, schemas
+from .. import auth, limits, models, schemas
 from ..database import get_db
 
 router = APIRouter(prefix="/api/story-cards", tags=["story-cards"])
@@ -50,6 +50,10 @@ def create_story_card(
     owner = db.get(owner_model, owner_id)
     if owner is None or owner.user_id != user.id:
         raise HTTPException(404, "Owner not found")
+    limits.check_row_cap(
+        "story_cards", db, user,
+        scenario_id=payload.scenario_id, adventure_id=payload.adventure_id,
+    )
     card = models.StoryCard(**payload.model_dump())
     db.add(card)
     db.commit()

backend/app/schemas.py

@@ -1,7 +1,26 @@
 from datetime import datetime
-from typing import Literal
+from typing import Annotated, Literal
 
-from pydantic import BaseModel, ConfigDict
+from pydantic import BaseModel, ConfigDict, Field
+
+# Length caps (Phase 9). The VARCHAR ones are correctness, not just abuse
+# limits: Postgres enforces column lengths (SQLite never did), so anything
+# longer must be a 422 here rather than a 500 at INSERT. Text-column caps are
+# generous abuse ceilings a legitimate player won't hit.
+NAME_MAX = 200          # titles/names — VARCHAR(200)
+TAGS_MAX = 500          # VARCHAR(500)
+CARD_TYPE_MAX = 100     # VARCHAR(100)
+PROSE_MAX = 50_000      # memory, author's note, prompts, entries, notes...
+SCRIPT_MAX = 200_000    # one JS source
+ACTION_MAX = 20_000     # one player action
+MEMORY_TEXT_MAX = 5_000
+
+Name = Annotated[str, Field(max_length=NAME_MAX)]
+Tags = Annotated[str, Field(max_length=TAGS_MAX)]
+CardType = Annotated[str, Field(max_length=CARD_TYPE_MAX)]
+Prose = Annotated[str, Field(max_length=PROSE_MAX)]
+ScriptSource = Annotated[str, Field(max_length=SCRIPT_MAX)]
+ActionText = Annotated[str, Field(max_length=ACTION_MAX)]
 
 
 class ORMModel(BaseModel):
@@ -11,11 +30,11 @@ class ORMModel(BaseModel):
 # ---------- Story cards ----------
 
 class StoryCardBase(BaseModel):
-    type: str = ""
-    name: str = ""
-    keys: str = ""
-    entry: str = ""
-    notes: str = ""
+    type: CardType = ""
+    name: Name = ""
+    keys: Prose = ""
+    entry: Prose = ""
+    notes: Prose = ""
 
 
 class StoryCardCreate(StoryCardBase):
@@ -24,11 +43,11 @@ class StoryCardCreate(StoryCardBase):
 
 
 class StoryCardUpdate(BaseModel):
-    type: str | None = None
-    name: str | None = None
-    keys: str | None = None
-    entry: str | None = None
-    notes: str | None = None
+    type: CardType | None = None
+    name: Name | None = None
+    keys: Prose | None = None
+    entry: Prose | None = None
+    notes: Prose | None = None
 
 
 class StoryCardOut(ORMModel, StoryCardBase):
@@ -40,13 +59,13 @@ class StoryCardOut(ORMModel, StoryCardBase):
 # ---------- Scenarios ----------
 
 class ScenarioBase(BaseModel):
-    title: str = "Untitled Scenario"
-    description: str = ""
-    prompt: str = ""
-    memory: str = ""
-    authors_note: str = ""
-    ai_instructions: str = ""
-    tags: str = ""
+    title: Name = "Untitled Scenario"
+    description: Prose = ""
+    prompt: Prose = ""
+    memory: Prose = ""
+    authors_note: Prose = ""
+    ai_instructions: Prose = ""
+    tags: Tags = ""
 
 
 class ScenarioCreate(ScenarioBase):
@@ -54,13 +73,13 @@ class ScenarioCreate(ScenarioBase):
 
 
 class ScenarioUpdate(BaseModel):
-    title: str | None = None
-    description: str | None = None
-    prompt: str | None = None
-    memory: str | None = None
-    authors_note: str | None = None
-    ai_instructions: str | None = None
-    tags: str | None = None
+    title: Name | None = None
+    description: Prose | None = None
+    prompt: Prose | None = None
+    memory: Prose | None = None
+    authors_note: Prose | None = None
+    ai_instructions: Prose | None = None
+    tags: Tags | None = None
     script_ids: list[int] | None = None
 
 
@@ -86,17 +105,17 @@ class ScenarioListItem(ORMModel):
 
 class AdventureCreate(BaseModel):
     scenario_id: int | None = None
-    title: str | None = None
+    title: Name | None = None
     # ${Placeholder} values collected from the player at start (AI Dungeon behavior).
     placeholders: dict[str, str] = {}
 
 
 class AdventureUpdate(BaseModel):
-    title: str | None = None
-    memory: str | None = None
-    authors_note: str | None = None
-    ai_instructions: str | None = None
-    story_summary: str | None = None
+    title: Name | None = None
+    memory: Prose | None = None
+    authors_note: Prose | None = None
+    ai_instructions: Prose | None = None
+    story_summary: Prose | None = None
     auto_summarize: bool | None = None
     memory_bank_enabled: bool | None = None
 
@@ -112,12 +131,12 @@ class ActionOut(ORMModel):
 
 
 class ActionUpdate(BaseModel):
-    text: str
+    text: ActionText
 
 
 class ActionCreate(BaseModel):
     type: Literal["do", "say", "story", "continue"]
-    text: str = ""
+    text: ActionText = ""
 
 
 class AdventureOut(ORMModel):
@@ -153,11 +172,11 @@ class MemoryOut(ORMModel):
 
 
 class MemoryCreate(BaseModel):
-    text: str
+    text: Annotated[str, Field(max_length=MEMORY_TEXT_MAX)]
 
 
 class MemoryUpdate(BaseModel):
-    text: str | None = None
+    text: Annotated[str, Field(max_length=MEMORY_TEXT_MAX)] | None = None
     pinned: bool | None = None
     forgotten: bool | None = None
 
@@ -174,12 +193,12 @@ class AdventureListItem(ORMModel):
 # ---------- Scripts ----------
 
 class ScriptBase(BaseModel):
-    name: str = "Untitled Script"
-    description: str = ""
-    library_js: str = ""
-    input_js: str = ""
-    context_js: str = ""
-    output_js: str = ""
+    name: Name = "Untitled Script"
+    description: Prose = ""
+    library_js: ScriptSource = ""
+    input_js: ScriptSource = ""
+    context_js: ScriptSource = ""
+    output_js: ScriptSource = ""
 
 
 class ScriptCreate(ScriptBase):
@@ -187,12 +206,12 @@ class ScriptCreate(ScriptBase):
 
 
 class ScriptUpdate(BaseModel):
-    name: str | None = None
-    description: str | None = None
-    library_js: str | None = None
-    input_js: str | None = None
-    context_js: str | None = None
-    output_js: str | None = None
+    name: Name | None = None
+    description: Prose | None = None
+    library_js: ScriptSource | None = None
+    input_js: ScriptSource | None = None
+    context_js: ScriptSource | None = None
+    output_js: ScriptSource | None = None
 
 
 class ScriptOut(ORMModel, ScriptBase):
@@ -203,7 +222,7 @@ class ScriptOut(ORMModel, ScriptBase):
 
 class ScriptTestRequest(BaseModel):
     hook: Literal["input", "context", "output"]
-    text: str = ""
+    text: Prose = ""
     state: dict = {}
 
 
@@ -222,17 +241,19 @@ class AdventureScriptOut(ORMModel):
 
 class AdventureScriptUpdate(BaseModel):
     enabled: bool | None = None
-    library_js: str | None = None
-    input_js: str | None = None
-    context_js: str | None = None
-    output_js: str | None = None
+    library_js: ScriptSource | None = None
+    input_js: ScriptSource | None = None
+    context_js: ScriptSource | None = None
+    output_js: ScriptSource | None = None
 
 
 # ---------- Auth (Phase 8) ----------
 
 class AuthCredentials(BaseModel):
-    email: str
-    password: str
+    email: Annotated[str, Field(max_length=320)]  # VARCHAR(320)
+    # Upper bound keeps scrypt cost flat — hashing megabyte "passwords" is CPU
+    # an attacker would otherwise get for free.
+    password: Annotated[str, Field(max_length=128)]
 
 
 # ---------- Settings ----------
@@ -259,17 +280,19 @@ ScenarioOut.model_rebuild()
 
 
 class SettingsUpdate(BaseModel):
-    endpoint_url: str | None = None
-    api_key: str | None = None
-    model: str | None = None
-    api_mode: str | None = None
-    temperature: float | None = None
-    max_output_tokens: int | None = None
-    reasoning_max_tokens: int | None = None
-    context_token_budget: int | None = None
-    narrator_prompt: str | None = None
+    endpoint_url: Annotated[str, Field(max_length=500)] | None = None  # VARCHAR(500)
+    # Encryption expands the stored value ~4/3 into the same VARCHAR(500):
+    # 256 plaintext chars is the largest safe input ("enc:" + Fernet + base64).
+    api_key: Annotated[str, Field(max_length=256)] | None = None
+    model: Name | None = None
+    api_mode: Annotated[str, Field(max_length=20)] | None = None
+    temperature: Annotated[float, Field(ge=0, le=5)] | None = None
+    max_output_tokens: Annotated[int, Field(ge=1, le=100_000)] | None = None
+    reasoning_max_tokens: Annotated[int, Field(ge=0, le=100_000)] | None = None
+    context_token_budget: Annotated[int, Field(ge=256, le=200_000)] | None = None
+    narrator_prompt: Prose | None = None
     stream: bool | None = None
-    summary_model: str | None = None
-    embedding_model: str | None = None
-    memory_bank_capacity: int | None = None
-    memory_top_k: int | None = None
+    summary_model: Name | None = None
+    embedding_model: Name | None = None
+    memory_bank_capacity: Annotated[int, Field(ge=1, le=1000)] | None = None
+    memory_top_k: Annotated[int, Field(ge=1, le=50)] | None = None

backend/app/security.py

@@ -7,7 +7,9 @@ Everything keys off one server-side secret:
 The secret comes from AIDND_SECRET_KEY, or is auto-generated once into
 `secret.key` next to the database so local installs and Docker volumes work
 with zero configuration (losing the file logs everyone out and orphans
-stored API keys — users just re-enter them).
+stored API keys — users just re-enter them). Multi-user deploys must set the
+env var: hosted filesystems are ephemeral, and a secret.key regenerated on
+every deploy would silently log out all users each time.
 
 Passwords use hashlib.scrypt (stdlib, OpenSSL-backed) so we don't need a
 separate hashing dependency.
@@ -27,9 +29,19 @@ _SECRET_FILE = DB_PATH.parent / "secret.key"
 
 
 def _load_secret() -> bytes:
-    env = os.environ.get("AIDND_SECRET_KEY")
+    env = os.environ.get("AIDND_SECRET_KEY", "").strip()
     if env:
         return env.encode()
+    # Same flag parse as auth.MULTI_USER (auth imports this module, so it
+    # can't be imported from there).
+    if os.environ.get("AIDND_MULTI_USER", "").strip().lower() in ("1", "true", "yes", "on"):
+        raise RuntimeError(
+            "AIDND_SECRET_KEY must be set when AIDND_MULTI_USER is on: an "
+            "auto-generated secret.key on an ephemeral hosted filesystem would "
+            "rotate on every deploy, logging out every user and orphaning "
+            "their stored API keys. Generate one with: "
+            "python -c \"import secrets; print(secrets.token_urlsafe(48))\""
+        )
     if _SECRET_FILE.exists():
         return _SECRET_FILE.read_bytes().strip()
     secret = secrets.token_urlsafe(48).encode()

backend/requirements.txt

@@ -5,3 +5,5 @@ pydantic>=2.7
 httpx>=0.27
 tiktoken>=0.7
 quickjs>=1.19
+cryptography>=42
+psycopg[binary]>=3.2

plan/09-phase-hardening.md

@@ -53,3 +53,26 @@ Render tier: free tier sleeps after idle + has no persistent disk).
 Running the production Docker image locally with `MULTI_USER=true`: a hostile user cannot hang
 the server with a `while(true)` script, cannot see another user's data or the debug log, gets
 rate-limited instead of burning the demo key, and the app streams turns normally the whole time.
+
+### Verified 2026-07-07 (uvicorn, `MULTI_USER=1`, fresh SQLite DB, curl)
+
+- **Fail-fast secret:** `import app.main` with `MULTI_USER=1` and no `AIDND_SECRET_KEY` raises
+  the RuntimeError as designed (won't boot).
+- **`while(true)` script:** `POST /api/scripts/{id}/test` on an `input_js` infinite loop returns
+  `InternalError: interrupted` (engine time limit) — server stays responsive afterward.
+- **Cross-user isolation:** guest B sees `[]` for scripts, gets 404 on guest A's script id;
+  guest A keeps its own row. No leakage.
+- **Debug log:** `GET /api/debug/requests` → 403 in multi-user mode.
+- **Rate limiting:** 12 rapid `POST /api/auth/register` → 429 after the 10th (auth scope, 10/300s).
+- **Body size:** 3 MB body to `POST /api/scenarios` → 413 (limit 2 MB) via BodySizeLimitMiddleware.
+- **Security headers:** CSP, `x-frame-options: DENY`, `x-content-type-options: nosniff`,
+  `referrer-policy: same-origin` on every response — including the SSE stream.
+- **Docs disabled:** Swagger UI and OpenAPI schema not served (`/docs`, `/openapi.json` fall
+  through to the SPA `index.html`; no `swagger-ui`, no API schema exposed).
+- **SSE streaming:** `POST /api/adventures/{id}/actions` streams `text/event-stream` with
+  `x-accel-buffering: no`, chunked, incremental events — the pure-ASGI middlewares don't buffer.
+  (No LLM key configured here, so it streams the "No model configured" error event; a *live*
+  provider turn through this path was verified end-to-end in Phase 8.)
+
+All Phase 9 exit criteria met. Not yet exercised: Postgres (`DATABASE_URL`) path and the
+Docker production image specifically — both are Phase 10 deploy steps.