diff --git a/.gitea/workflows/git-to-ptero.yaml b/.gitea/workflows/git-to-ptero.yaml
index 3489c64..3ff6e79 100644
--- a/.gitea/workflows/git-to-ptero.yaml
+++ b/.gitea/workflows/git-to-ptero.yaml
@@ -34,6 +34,17 @@ on:
 #
 # docs/deployment.md carries the design and the rollback procedure.
 
+# Least privilege (CI-003). This job never writes back to the repository; it
+# holds the SSH key to the production node, which makes it the most valuable
+# job in either forge to compromise.
+permissions:
+  contents: read
+
+# Actions pinned to a commit, version in the comment. A tag is a moving
+# pointer, and moving `v4` here means running arbitrary code in the job that
+# holds that key. If the Gitea runner ever fails to resolve a commit ref, it
+# fails on the checkout step — loudly, like the `@v7` that did not exist.
+
 jobs:
   deploy-to-sftp:
     runs-on: ubuntu-latest
@@ -42,10 +53,10 @@ jobs:
       # Was @v7, which does not exist (latest major is v5): the workflow
       # failed on its very first step.
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262  # v4
 
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065  # v5
         with:
           python-version: '3.12'
 
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c6fce70..95d343e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,6 +15,12 @@ concurrency:
 permissions:
   contents: read
 
+# Third-party actions are pinned to a commit, with the version in a comment
+# (CI-003). A tag is a moving pointer: whoever can move `v4` runs code in a
+# job that holds this repository's token. The comment is what makes the pin
+# maintainable — a bare 40-character hash tells a reader nothing about
+# whether it is current. Dependabot updates both together.
+
 env:
   PYTHON_VERSION: '3.12'
 
@@ -23,10 +29,10 @@ jobs:
     name: Security Audit
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262  # v4
 
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065  # v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}
           cache: 'pip'
@@ -46,10 +52,10 @@ jobs:
     name: Lint with Ruff
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262  # v4
 
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065  # v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}
 
@@ -71,10 +77,10 @@ jobs:
     name: Security Scan
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262  # v4
 
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065  # v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}
           cache: 'pip'
@@ -96,10 +102,10 @@ jobs:
     runs-on: ubuntu-latest
     needs: [security-audit, lint]
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262  # v4
 
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065  # v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}
           cache: 'pip'
diff --git a/README.md b/README.md
index f49ee07..1c512a2 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@ de la barre latérale (voir `docs/translations.md`).
 ```bash
 python -m venv .venv
 .venv/Scripts/pip install -r requirements.txt -r requirements-dev.txt
-cp app/.env.exemple .env      # puis remplir les valeurs
+cp app/.env.example .env      # puis remplir SECRET_KEY et DATABASE_URL
 .venv/Scripts/python run.py   # développement, http://127.0.0.1:5000
 ```
 
diff --git a/app/.env.example b/app/.env.example
new file mode 100644
index 0000000..e6cc4d2
--- /dev/null
+++ b/app/.env.example
@@ -0,0 +1,115 @@
+# Team Tryouts — environment variables
+#
+# Copy to .env and fill in. Every value here is a PRODUCTION-SAFE default:
+# copying this file and changing nothing gives a locked-down configuration
+# that refuses to start until the two required secrets are set, rather than
+# a working one that happens to be wide open (OPS-003).
+#
+# The previous version shipped FLASK_DEBUG=true under a heading that said
+# "fill in the values for production". The Werkzeug debugger executes code
+# submitted through the browser, so that one line turned a copy-paste into a
+# remote shell.
+#
+# For local development, see the DEVELOPMENT block at the bottom.
+
+# =============================================================================
+# Required — the application refuses to start without these
+# =============================================================================
+
+# Generate with: python -c "import secrets; print(secrets.token_hex(32))"
+# Never reuse one between environments: this key signs session cookies, so
+# whoever holds it can forge a session for any account.
+SECRET_KEY=
+
+# Expected form: postgresql://user:password@host:5432/database
+# The psycopg 3 driver is named for you by create_app(); postgresql:// alone
+# would send SQLAlchemy looking for psycopg2, which is not installed.
+DATABASE_URL=
+
+# =============================================================================
+# Security — these defaults assume HTTPS in front. Do not relax them on a
+# deployed instance.
+# =============================================================================
+
+# Session cookies are only sent over HTTPS.
+SESSION_COOKIE_SECURE=true
+
+# Plain HTTP is redirected to HTTPS.
+FORCE_HTTPS=true
+
+# The Werkzeug debugger is a remote code execution primitive by design.
+# Never true on anything reachable from a network you do not control.
+FLASK_DEBUG=false
+
+# Inline <script> without a nonce. Off: every block carries one, and turning
+# this on gives up the protection that would have blocked the stored XSS
+# (SEC-WEB-001). It exists as an escape hatch, not as a setting to tune.
+CSP_ALLOW_INLINE_SCRIPT=false
+
+# Comma-separated origins allowed to call this API cross-site. Empty means
+# no CORS policy at all, which is correct: the site renders its own HTML on
+# one origin and needs none.
+CORS_ALLOWED_ORIGINS=
+
+# =============================================================================
+# Networking
+# =============================================================================
+
+# Interface Waitress binds. 127.0.0.1 keeps it reachable only through the
+# local reverse proxy; 0.0.0.0 exposes it directly and is only correct if
+# something else in front is doing the filtering.
+HOST=127.0.0.1
+PORT=5000
+
+# Whether to believe X-Forwarded-For, and from whom. This decides which IP
+# the rate limiter and the audit log record.
+#
+#   (empty)  — trust nobody. Correct when nothing proxies the app.
+#   127.0.0.1 — trust a reverse proxy on this same machine. The usual case.
+#   *        — trust everyone. Only ever correct if the app cannot be reached
+#              except through the proxy, at the network level. Otherwise any
+#              caller can claim any IP and walk around the rate limit.
+#
+# See docs/deployment.md before changing this (OPS-002).
+TRUSTED_PROXY=127.0.0.1
+
+# =============================================================================
+# Optional — Discord
+# =============================================================================
+
+# Leave ENABLE_DISCORD_BOT=false and the token empty to run without Discord.
+ENABLE_DISCORD_BOT=false
+DISCORD_BOT_TOKEN=
+
+# OAuth2, for "Connect Discord" on the sign-up page.
+# Create an application at https://discord.com/developers/applications
+DISCORD_CLIENT_ID=
+DISCORD_CLIENT_SECRET=
+DISCORD_REDIRECT_URI=https://your-domain/auth/discord/callback
+
+# =============================================================================
+# Optional — storage
+# =============================================================================
+
+# Where uploaded contracts live. Empty means `documents/` beside the
+# application. Set it to a path OUTSIDE the deployment directory if you move
+# to a release-directory layout, or a deployment will take the documents with
+# it (OPS-011, app/storage.py).
+DOCUMENTS_ROOT=
+
+# Tables are created at startup when missing. Set to false once Alembic owns
+# the schema (DB-002/DB-004): create_all() never ALTERs, so a column added to
+# a model is silently absent from an existing database.
+AUTO_CREATE_TABLES=true
+
+# =============================================================================
+# DEVELOPMENT ONLY — the values to change on a laptop, and nowhere else
+# =============================================================================
+#
+#   FLASK_DEBUG=true            reloader and interactive debugger
+#   SESSION_COOKIE_SECURE=false cookies over plain HTTP
+#   FORCE_HTTPS=false           no redirect to HTTPS
+#   DISCORD_REDIRECT_URI=http://localhost:5000/auth/discord/callback
+#
+# `python run.py` reads DEV_HOST and DEV_PORT rather than HOST and PORT, so a
+# development session cannot accidentally inherit a production binding.
diff --git a/app/.env.exemple b/app/.env.exemple
deleted file mode 100644
index 97044b3..0000000
--- a/app/.env.exemple
+++ /dev/null
@@ -1,34 +0,0 @@
-# Team Tryouts Application - Environment Variables
-# Copy this file to .env and fill in the values for production
-
-# Security Configuration
-# Generate a secure random secret key: python -c "import secrets; print(secrets.token_hex(32))"
-SECRET_KEY=flask_app_secret_key
-
-# Set to 'true' in production to enable secure cookies (requires HTTPS)
-SESSION_COOKIE_SECURE=false
-FORCE_HTTPS=false
-
-# Flask Debug Mode - Set to 'true' only in development
-FLASK_DEBUG=true
-
-# Discord Bot Token (required for notifications)
-# This is the UdeS Esports BOT token, it will send notifications to people that have their
-# Dicord_User_ID in the db / remove if you don't want discord notifs.
-DISCORD_BOT_TOKEN=my_discord_bot_token
-
-# Discord OAuth2 Configuration (for "Connect Discord" on sign-up page)
-# Create an application at https://discord.com/developers/applications
-DISCORD_CLIENT_ID=
-DISCORD_CLIENT_SECRET=
-DISCORD_REDIRECT_URI=http://localhost:5000/auth/discord/callback
-
-#where to find the db (hosted on render for now)
-#Forme attendue : postgresql://utilisateur:motdepasse@hote:5432/base
-#Le pilote psycopg 3 est nomme automatiquement par create_app().
-DATABASE_URL=URI_vers_db_posgres
-
-
-#Where the app will be hosted (corresponds to: localhost:5000 in local)
-HOST=127.0.0.1
-PORT=5000
\ No newline at end of file
diff --git a/app/templates/layouts/base.html b/app/templates/layouts/base.html
index 2d29dc3..9e3e992 100644
--- a/app/templates/layouts/base.html
+++ b/app/templates/layouts/base.html
@@ -4,7 +4,22 @@
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>{% block title %}Team Tryout Management{% endblock %}</title>
-    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.5.1/css/all.min.css">
+    {# Subresource integrity (QUA-004). Without it, whoever controls the CDN
+       controls what runs on every page of this site — and the CSP names these
+       hosts as allowed, so it would not object.
+
+       What SRI does and does not do: it pins this exact file, so the browser
+       refuses a version that has been altered since. It does not prove the
+       file was honest when the hash was taken. This hash is the one cdnjs
+       publishes for the release, not one derived from the copy we downloaded.
+
+       integrity requires crossorigin. Changing the version means changing
+       the hash, or the asset silently stops loading. #}
+    <link rel="stylesheet"
+          href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.5.1/css/all.min.css"
+          integrity="sha512-DTOQO9RWCH3ppGqcWaEA1BIZOC6xxalwEsw9c2QQeAIftl+Vegovlnee1c9QX4TctnWMn13TZye+giMm8e2LwA=="
+          crossorigin="anonymous"
+          referrerpolicy="no-referrer">
     <link rel="stylesheet" href="{{ url_for('static', filename='css/style.css') }}">
     <link rel="icon" type="image/svg+xml" href="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'><text y='.9em' font-size='90'>🏆</text></svg>">
 </head>
diff --git a/app/templates/pages/calendar.html b/app/templates/pages/calendar.html
index 91574a5..e62eab0 100644
--- a/app/templates/pages/calendar.html
+++ b/app/templates/pages/calendar.html
@@ -114,8 +114,19 @@
 {% endblock %}
 
 {% block scripts %}
-<link href="https://cdn.jsdelivr.net/npm/fullcalendar@6.1.10/index.global.min.css" rel="stylesheet">
-<script src="https://cdn.jsdelivr.net/npm/fullcalendar@6.1.10/index.global.min.js"></script>
+{# The stylesheet that used to sit here — index.global.min.css — does not
+   exist. FullCalendar 6 bundles its styles into the JS, and that file is not
+   in the published package: the link had been answering 404 on every calendar
+   load since the upgrade. A failed stylesheet is silent in the browser, which
+   is why it survived.
+
+   Integrity pins the bundle (QUA-004): this file is executable script from a
+   third party, on the page that shows every match in the club. See the note
+   in layouts/base.html for what SRI does and does not promise. #}
+<script src="https://cdn.jsdelivr.net/npm/fullcalendar@6.1.10/index.global.min.js"
+        integrity="sha384-WfE/vOHqht3KDj6FvpwQUf3UxEPUHoGJ3w1yZ8rhpLWnVigt8HjXL2zXqtcfS7mf"
+        crossorigin="anonymous"
+        referrerpolicy="no-referrer"></script>
 <script nonce="{{ csp_nonce }}">
 var canScheduleMatches = {% if current_user.can_schedule_matches() %}true{% else %}false{% endif %};
 
diff --git a/docs/deployment.md b/docs/deployment.md
index 72648b4..1ce21f6 100644
--- a/docs/deployment.md
+++ b/docs/deployment.md
@@ -62,6 +62,52 @@ BACKUP_RETENTION_DAYS=30
 
 **Important**: Never commit `.env` to version control.
 
+Start from `app/.env.example`, which carries production-safe defaults and
+documents every variable. Copying it verbatim gives a configuration that
+refuses to start until `SECRET_KEY` and `DATABASE_URL` are filled in, rather
+than one that starts and is wide open (OPS-003).
+
+### Binding and proxy trust — read this before going live (OPS-002)
+
+Two variables decide whether the rate limiter, the account lockout and the
+audit log mean anything: `HOST` and `TRUSTED_PROXY`. Their built-in defaults
+(`0.0.0.0` and `*`) are what this application has always done, kept so that
+an existing deployment is not changed under it — **they are not the right
+values**, and which values are right depends on your topology.
+
+`TRUSTED_PROXY` decides whose `X-Forwarded-For` Waitress believes, and
+therefore which address is recorded and counted. Getting it wrong fails in
+one of two directions:
+
+- **too trusting** — anyone who can reach the app without going through nginx
+  sets their own client address. Rate limiting, lockout and the `ip=` field
+  in `auth.log` all become suggestions;
+- **not trusting enough** — every request appears to come from the proxy. One
+  shared bucket, so the first person to mistype a password five times locks
+  the limiter for the whole club.
+
+Find your case:
+
+| Topology | `HOST` | `TRUSTED_PROXY` | Why |
+|---|---|---|---|
+| **nginx on the same machine as the app** (the common case) | `127.0.0.1` | `127.0.0.1` | Waitress is unreachable except through nginx, and only nginx's forwarded header is believed |
+| **App in a Pterodactyl container, nginx elsewhere** | `0.0.0.0` | the proxy's address on the container network, e.g. `10.0.0.5` | The app must accept connections from outside the container, so it cannot bind to loopback. Name the proxy rather than trusting `*` |
+| **Same as above, but the port is only reachable from the proxy** (firewall or container network) | `0.0.0.0` | `*` | Acceptable *only* because the network already prevents anyone else connecting. If that is not enforced, this is the first failure above |
+| **No proxy at all** | `0.0.0.0` | *(empty)* | Nothing forwards anything; the peer address is the client |
+
+To find out which one you are in, on the node:
+
+```powershell
+# Does anything answer on the app's port from outside the machine?
+Test-NetConnection <public-ip> -Port 5000
+# What address does nginx come from, as the app sees it?
+#   Set TRUSTED_PROXY= (empty) briefly, make one request, and read auth.log:
+#   the ip= field is then the real peer — which is the proxy.
+```
+
+`wsgi.py` prints a warning at startup while both defaults are in place, so an
+unconfigured deployment says so in the Pterodactyl console.
+
 ## Step 3: Configure Nginx
 
 1. Copy `app/nginx.conf` to your Nginx installation directory (e.g., `C:\nginx\conf\`)
diff --git a/tests/test_subresource_integrity.py b/tests/test_subresource_integrity.py
new file mode 100644
index 0000000..3a670af
--- /dev/null
+++ b/tests/test_subresource_integrity.py
@@ -0,0 +1,104 @@
+"""Third-party assets are pinned (QUA-004).
+
+Two CDNs serve this site: cdnjs for Font Awesome, jsDelivr for FullCalendar.
+The CSP names both as allowed origins, so neither would be stopped by it —
+whoever controls those hosts controls what runs on every page, and on the
+calendar page that includes executable script.
+
+`integrity` pins each file: the browser refuses one that has been altered
+since the hash was taken. It does not prove the file was honest at that
+moment. Worth being clear about, because SRI is often read as more than it
+is.
+
+This is a guard, not a test of behaviour. Its job is to fail the day someone
+adds a CDN URL without a hash, or bumps a version and leaves the old hash
+behind — the second of which fails *silently* in a browser, since a script
+that fails its integrity check simply does not run.
+"""
+
+import re
+
+import pytest
+
+TEMPLATES = 'app/templates'
+
+#: Hosts we deliberately load from. Anything else on a template needs a
+#: decision, not a hash.
+KNOWN_CDNS = ('cdnjs.cloudflare.com', 'cdn.jsdelivr.net')
+
+#: Discord avatars. Not a subresource — an <img> src built at render time,
+#: which cannot carry an integrity hash and executes nothing.
+IMAGE_ONLY_HOSTS = ('cdn.discordapp.com',)
+
+
+def _templates():
+    import os
+
+    for root, _dirs, files in os.walk(TEMPLATES):
+        for name in files:
+            if name.endswith('.html'):
+                path = os.path.join(root, name)
+                with open(path, encoding='utf-8') as handle:
+                    yield path, handle.read()
+
+
+def _tags_loading_from(host, markup):
+    """Every <script src> and <link href> pointing at this host."""
+    pattern = re.compile(
+        r'<(script|link)\b[^>]*?(?:src|href)\s*=\s*"https://' + re.escape(host) + r'[^"]*"[^>]*>',
+        re.IGNORECASE | re.DOTALL,
+    )
+    return pattern.findall(markup), pattern
+
+
+@pytest.mark.parametrize('host', KNOWN_CDNS)
+def test_every_asset_from_a_cdn_carries_an_integrity_hash(host):
+    offenders = []
+    for path, markup in _templates():
+        _names, pattern = _tags_loading_from(host, markup)
+        for tag in pattern.finditer(markup):
+            if 'integrity=' not in tag.group(0):
+                offenders.append(f'{path}: {tag.group(0)[:120]}')
+
+    assert not offenders, 'CDN asset loaded without integrity:\n' + '\n'.join(offenders)
+
+
+@pytest.mark.parametrize('host', KNOWN_CDNS)
+def test_integrity_is_paired_with_crossorigin(host):
+    """A browser ignores integrity on a request it did not make in CORS mode,
+    so the hash without crossorigin is decoration."""
+    offenders = []
+    for path, markup in _templates():
+        _names, pattern = _tags_loading_from(host, markup)
+        for tag in pattern.finditer(markup):
+            if 'integrity=' in tag.group(0) and 'crossorigin=' not in tag.group(0):
+                offenders.append(f'{path}: {tag.group(0)[:120]}')
+
+    assert not offenders, 'integrity without crossorigin:\n' + '\n'.join(offenders)
+
+
+def test_no_unexpected_third_party_host_appears():
+    """A new CDN is a decision — a supply-chain dependency and a CSP entry —
+    not something to notice later."""
+    allowed = set(KNOWN_CDNS) | set(IMAGE_ONLY_HOSTS)
+    found = set()
+    for _path, markup in _templates():
+        found.update(re.findall(r'https://([a-z0-9.-]+)/', markup, re.IGNORECASE))
+
+    unexpected = {host for host in found if host not in allowed}
+    # Documentation links in comments are fine; only loaded assets matter.
+    unexpected -= {'discord.com', 'www.w3.org', 'developer.mozilla.org'}
+
+    assert not unexpected, f'unexpected third-party hosts in templates: {sorted(unexpected)}'
+
+
+def test_the_csp_and_the_templates_agree(app):
+    """A hash is no use if the CSP blocks the request outright, and an origin
+    left in the CSP after its last use is a widened policy nobody needs."""
+    with app.test_request_context():
+        from app.app import build_csp
+
+        policy = build_csp(nonce='x', allow_inline_script=False)
+
+    for host in KNOWN_CDNS:
+        assert host in policy, f'{host} is loaded by a template but absent from the CSP'
diff --git a/wsgi.py b/wsgi.py
index 791a5dd..ef3b1f9 100644
--- a/wsgi.py
+++ b/wsgi.py
@@ -8,8 +8,33 @@ Usage:
     python wsgi.py
 
 Configuration via environment variables:
-    PORT: Port to listen on (default: 5000)
+    HOST: interface to bind (default: 0.0.0.0 — see the note below)
+    PORT: Port to listen on (default: 10000)
     WAITRESS_THREADS: Number of worker threads (default: CPU*2+1)
+    TRUSTED_PROXY: whose X-Forwarded-For to believe (default: * — see below)
+
+A note on the three defaults above (OPS-002)
+--------------------------------------------
+They are what this file has always done, kept deliberately. Two of them are
+known to be wrong, and they are *still* not changed here, because the right
+value depends on something the repository cannot tell us: is nginx on the
+same machine as the app, or is the app in a Pterodactyl container with nginx
+elsewhere?
+
+Guessing fails in one of two directions, and neither is recoverable by
+reading a log:
+
+  - bind to loopback when nginx is on another host, and the site is simply
+    gone;
+  - stop trusting X-Forwarded-For when it was the only source of client
+    addresses, and every request looks like it comes from the proxy — one
+    shared rate-limit bucket, so the first person to mistype a password five
+    times locks the limiter for everybody.
+
+So: the values became settings, the safe values are what `.env.example`
+carries for a new deployment, and the existing one keeps working untouched
+until someone who knows the topology sets them. docs/deployment.md walks
+through both cases.
 """
 
 import multiprocessing
@@ -19,14 +44,65 @@ from app.app import create_app
 
 app = create_app()
 
+
+def proxy_settings():
+    """How much of X-Forwarded-For to believe, and from whom (OPS-002).
+
+    This decides which address the rate limiter counts against and which one
+    the audit log records as `ip=`.
+
+    The default is `*` — believe anyone. That is the setting the audit called
+    out for inverting the risk rather than fixing it: before it, rate
+    limiting was miscalibrated but closed; after it, forgeable on every
+    request by anyone who can reach the app directly. It stays the default
+    only because narrowing it blind can take the rate limiter down for every
+    legitimate user, and it is now one environment variable away instead of
+    being welded into the file.
+
+    Values:
+        ''          trust nobody; remote_addr is the peer. Correct when
+                    nothing proxies the app.
+        '127.0.0.1' trust a reverse proxy on this same machine. The usual
+                    case, and what .env.example ships.
+        '*'         trust everyone. Only correct when the app cannot be
+                    reached except through the proxy, at the network level.
+
+    Returns:
+        dict: keyword arguments for waitress.serve.
+    """
+    trusted = os.getenv('TRUSTED_PROXY', '*').strip()
+
+    if not trusted:
+        return {'clear_untrusted_proxy_headers': True}
+
+    return {
+        'trusted_proxy': trusted,
+        'trusted_proxy_count': int(os.getenv('TRUSTED_PROXY_COUNT', 1)),
+        'trusted_proxy_headers': {'x-forwarded-for', 'x-forwarded-proto'},
+        'clear_untrusted_proxy_headers': True,
+    }
+
+
 if __name__ == '__main__':
     from waitress import serve
 
     port = int(os.getenv('PORT', 10000))
     threads = int(os.getenv('WAITRESS_THREADS', multiprocessing.cpu_count() * 2 + 1))
-    host = os.getenv('HOST', '0.0.0.0')  # Bind to localhost by default (Nginx reverse proxy)
+    # The comment that used to sit here said "Bind to localhost by default
+    # (Nginx reverse proxy)" next to a default of 0.0.0.0 — it described the
+    # intention and the code did the opposite, which is worse than either:
+    # the app was reachable directly and nobody reading the file would have
+    # known. The default is unchanged; the comment now says what it does.
+    host = os.getenv('HOST', '0.0.0.0')  # noqa: S104 — see the module docstring
 
     print(f'Starting Waitress server on {host}:{port} with {threads} threads')
+    if host == '0.0.0.0' and os.getenv('TRUSTED_PROXY', '*') == '*':  # noqa: S104
+        print(
+            'WARNING: listening on every interface and trusting X-Forwarded-For from '
+            'anyone. If this port is reachable without going through nginx, the rate '
+            'limiter and the audit log can be fed any address a caller likes. '
+            'Set HOST and TRUSTED_PROXY — see docs/deployment.md (OPS-002).'
+        )
     serve(
         app,
         host=host,
@@ -35,9 +111,5 @@ if __name__ == '__main__':
         # Graceful shutdown settings
         channel_timeout=30,  # Seconds to wait for in-flight requests
         cleanup_interval=30,
-        # Waitress Proxy Settings
-        trusted_proxy='*',
-        trusted_proxy_count=1,
-        trusted_proxy_headers={'x-forwarded-for', 'x-forwarded-proto'},
-        clear_untrusted_proxy_headers=True,
+        **proxy_settings(),
     )