diff --git a/backend/app/routes/codex.py b/backend/app/routes/codex.py
index f89ab93..2938cdc 100644
--- a/backend/app/routes/codex.py
+++ b/backend/app/routes/codex.py
@@ -3,7 +3,7 @@ contacted, shared across all users (spec §4)."""
 
 import uuid
 
-from fastapi import APIRouter, Depends, HTTPException, status
+from fastapi import APIRouter, Depends, HTTPException, Query, status
 from sqlalchemy import desc, func, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
@@ -126,7 +126,9 @@ def _entity_card(entity: Entity, discoverer: str | None) -> dict:
 async def list_codex(
     rarity: str | None = None,
     sort: str = "recent",
-    limit: int = 60,
+    # Bounded at the edge: an unvalidated `?limit=-1` reached Postgres as a
+    # negative LIMIT and returned a 500 to an unauthenticated caller.
+    limit: int = Query(default=60, ge=1, le=200),
     db: AsyncSession = Depends(get_db),
 ):
     query = select(Entity)
diff --git a/backend/app/schemas.py b/backend/app/schemas.py
index 5116b68..81adc5c 100644
--- a/backend/app/schemas.py
+++ b/backend/app/schemas.py
@@ -7,7 +7,9 @@ from pydantic import BaseModel, ConfigDict, Field
 class RegisterRequest(BaseModel):
     username: str = Field(min_length=3, max_length=32)
     password: str = Field(min_length=8, max_length=128)
-    email: str | None = None
+    # users.email is VARCHAR(255): without a cap here an over-long address
+    # reached Postgres and surfaced as a 500 instead of a validation error.
+    email: str | None = Field(default=None, max_length=255)
 
 
 class UserOut(BaseModel):
diff --git a/backend/tests/test_messages.py b/backend/tests/test_messages.py
new file mode 100644
index 0000000..20e648a
--- /dev/null
+++ b/backend/tests/test_messages.py
@@ -0,0 +1,131 @@
+"""Cross-user leak and impersonation pins for hunter-to-hunter whispers.
+
+routes/messages.py's docstring points at this file ("See
+tests/test_messages.py's cross-user leak tests") — it did not exist.
+"""
+
+import pytest
+
+
+async def _register(client, username, password="spookyspooky"):
+    resp = await client.post(
+        "/auth/register", json={"username": username, "password": password}
+    )
+    assert resp.status_code == 201, resp.text
+
+
+async def _login(client, username, password="spookyspooky"):
+    resp = await client.post(
+        "/auth/login", json={"username": username, "password": password}
+    )
+    assert resp.status_code == 200, resp.text
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "method,path",
+    [("get", "/api/messages"), ("get", "/api/messages/someone")],
+)
+async def test_message_reads_require_auth(client, method, path):
+    assert (await getattr(client, method)(path)).status_code == 401
+
+
+@pytest.mark.asyncio
+async def test_send_requires_auth(client):
+    resp = await client.post("/api/messages", json={"to": "anyone", "body": "hi"})
+    assert resp.status_code == 401
+
+
+@pytest.mark.asyncio
+async def test_third_party_cannot_read_a_thread(client):
+    await _register(client, "alice")
+    await _register(client, "bob")
+    await _register(client, "mallory")
+
+    await _login(client, "alice")
+    sent = await client.post("/api/messages", json={"to": "bob", "body": "the cellar is cold"})
+    assert sent.status_code == 201
+
+    # Mallory asks for the thread with each participant: the query is pinned
+    # to (caller, other) in both directions, so neither leg can match a
+    # message between two other people.
+    await _login(client, "mallory")
+    for name in ("alice", "bob"):
+        thread = await client.get(f"/api/messages/{name}")
+        assert thread.status_code == 200
+        assert thread.json()["messages"] == []
+    assert (await client.get("/api/messages")).json()["conversations"] == []
+
+
+@pytest.mark.asyncio
+async def test_sender_is_always_the_session_user(client):
+    await _register(client, "alice2")
+    await _register(client, "bob2")
+    await _register(client, "mallory2")
+
+    # An extra `from`/`sender` in the body must be inert — sender_id comes
+    # from the cookie, never the payload.
+    await _login(client, "mallory2")
+    resp = await client.post(
+        "/api/messages",
+        json={"to": "bob2", "body": "trust me", "from": "alice2", "sender": "alice2"},
+    )
+    assert resp.status_code == 201
+
+    await _login(client, "bob2")
+    thread = (await client.get("/api/messages/alice2")).json()
+    assert thread["messages"] == []
+    thread = (await client.get("/api/messages/mallory2")).json()
+    assert [m["body"] for m in thread["messages"]] == ["trust me"]
+
+
+@pytest.mark.asyncio
+async def test_body_length_is_capped_and_empty_rejected(client):
+    await _register(client, "alice3")
+    await _register(client, "bob3")
+    await _login(client, "alice3")
+
+    assert (
+        await client.post("/api/messages", json={"to": "bob3", "body": "   "})
+    ).status_code == 400
+    assert (
+        await client.post("/api/messages", json={"to": "bob3", "body": "x" * 1001})
+    ).status_code == 400
+
+
+@pytest.mark.asyncio
+async def test_send_is_rate_limited(client, monkeypatch):
+    from app.routes import messages as messages_module
+    from app.rate_limit import RateLimiter
+
+    monkeypatch.setattr(
+        messages_module, "send_limiter", RateLimiter(max_requests=2, window_seconds=3600)
+    )
+    await _register(client, "alice4")
+    await _register(client, "bob4")
+    await _login(client, "alice4")
+
+    for _ in range(2):
+        assert (
+            await client.post("/api/messages", json={"to": "bob4", "body": "again"})
+        ).status_code == 201
+    assert (
+        await client.post("/api/messages", json={"to": "bob4", "body": "again"})
+    ).status_code == 429
+
+
+@pytest.mark.asyncio
+async def test_conversation_row_carries_an_excerpt(client):
+    # The inbox preview key is `excerpt` (+ `truncated`); the frontend read a
+    # nonexistent `last_body` and rendered blank previews. Pin the name.
+    await _register(client, "alice5")
+    await _register(client, "bob5")
+    await _login(client, "alice5")
+    await client.post("/api/messages", json={"to": "bob5", "body": "z" * 300})
+
+    row = (await client.get("/api/messages")).json()["conversations"][0]
+    assert row["excerpt"] == "z" * 160
+    assert row["truncated"] is True
+    assert row["hunter"]["username"] == "bob5"
+    assert "email" not in row["hunter"]
+    assert "id" not in row["hunter"]
diff --git a/backend/tests/test_profile.py b/backend/tests/test_profile.py
new file mode 100644
index 0000000..f0959e6
--- /dev/null
+++ b/backend/tests/test_profile.py
@@ -0,0 +1,125 @@
+"""Privacy and authorization pins for the hunter profile layer.
+
+The module docstring of routes/profile.py promises three things that are
+easy to regress and were never actually tested: email appears on
+/api/profile/me and nowhere else, a veiled profile is indistinguishable
+from one that never existed, and editing is authenticated.
+"""
+
+import pytest
+
+
+async def _register(client, username, password="spookyspooky", **extra):
+    resp = await client.post(
+        "/auth/register", json={"username": username, "password": password, **extra}
+    )
+    assert resp.status_code == 201, resp.text
+    return resp.json()
+
+
+async def _login(client, username, password="spookyspooky"):
+    resp = await client.post(
+        "/auth/login", json={"username": username, "password": password}
+    )
+    assert resp.status_code == 200, resp.text
+
+
+@pytest.mark.asyncio
+async def test_profile_me_requires_auth(client):
+    assert (await client.get("/api/profile/me")).status_code == 401
+
+
+@pytest.mark.asyncio
+async def test_profile_patch_requires_auth(client):
+    resp = await client.patch("/api/profile", json={"display_name": "nobody"})
+    assert resp.status_code == 401
+
+
+@pytest.mark.asyncio
+async def test_email_only_on_own_profile(client):
+    await _register(client, "seer_a", email="seer@example.com")
+    await _login(client, "seer_a")
+
+    mine = (await client.get("/api/profile/me")).json()
+    assert mine["email"] == "seer@example.com"
+
+    public = (await client.get("/api/hunters/seer_a")).json()
+    assert "email" not in public
+    assert "password_hash" not in public
+    assert "id" not in public
+
+    roster = (await client.get("/api/hunters")).json()["hunters"]
+    for hunter in roster:
+        assert "email" not in hunter
+        assert "password_hash" not in hunter
+        assert "id" not in hunter
+
+
+@pytest.mark.asyncio
+async def test_patch_cannot_touch_another_hunter(client):
+    await _register(client, "seer_b")
+    await _register(client, "seer_c")
+    await _login(client, "seer_b")
+
+    # There is no user selector on PATCH at all — the payload is applied to
+    # the session's own row, so a username in the body is inert.
+    resp = await client.patch(
+        "/api/profile", json={"username": "seer_c", "display_name": "impostor"}
+    )
+    assert resp.status_code == 200
+    assert resp.json()["username"] == "seer_b"
+
+    victim = (await client.get("/api/hunters/seer_c")).json()
+    assert victim["display_name"] is None
+
+
+@pytest.mark.asyncio
+async def test_veiled_profile_is_404_and_absent_from_roster(client):
+    await _register(client, "seer_d")
+    await _login(client, "seer_d")
+    assert (await client.patch("/api/profile", json={"profile_public": False})).status_code == 200
+
+    assert (await client.get("/api/hunters/seer_d")).status_code == 404
+    roster = (await client.get("/api/hunters")).json()["hunters"]
+    assert all(h["username"] != "seer_d" for h in roster)
+
+
+@pytest.mark.asyncio
+async def test_text_fields_are_capped(client):
+    await _register(client, "seer_e")
+    await _login(client, "seer_e")
+
+    assert (
+        await client.patch("/api/profile", json={"display_name": "x" * 49})
+    ).status_code == 422
+    assert (await client.patch("/api/profile", json={"bio": "y" * 281})).status_code == 422
+    assert (await client.patch("/api/profile", json={"avatar_hue": 400})).status_code == 422
+    assert (await client.patch("/api/profile", json={"gender": "wraith"})).status_code == 422
+
+
+@pytest.mark.asyncio
+async def test_markup_in_profile_text_is_stored_verbatim_not_interpreted(client):
+    # The API is a JSON API: it stores exactly what was sent. The XSS defence
+    # is that every consumer renders it as a text node (see MessagesPage /
+    # HunterPage). Pinned so nobody "helpfully" starts emitting HTML here.
+    await _register(client, "seer_f")
+    await _login(client, "seer_f")
+    payload = "<img src=x onerror=alert(1)>"
+    resp = await client.patch("/api/profile", json={"bio": payload})
+    assert resp.json()["bio"] == payload
+    assert (await client.get("/api/hunters/seer_f")).json()["bio"] == payload
+
+
+@pytest.mark.asyncio
+async def test_register_rejects_absurdly_long_email(client):
+    # users.email is VARCHAR(255); without a schema cap this reached the
+    # database and came back as a 500 instead of a validation error.
+    resp = await client.post(
+        "/auth/register",
+        json={
+            "username": "seer_g",
+            "password": "spookyspooky",
+            "email": "a" * 300 + "@example.com",
+        },
+    )
+    assert resp.status_code == 422
diff --git a/frontend/src/pages/MessagesPage.tsx b/frontend/src/pages/MessagesPage.tsx
index fd29466..26ccd4d 100644
--- a/frontend/src/pages/MessagesPage.tsx
+++ b/frontend/src/pages/MessagesPage.tsx
@@ -28,7 +28,11 @@ type Hunter = {
 }
 type Conversation = {
   hunter: Hunter
-  last_body: string
+  // GET /api/messages calls this `excerpt` (first 160 chars) with a
+  // `truncated` flag beside it. This type used to say `last_body`, which the
+  // API has never sent — every inbox preview rendered as an empty string.
+  excerpt: string
+  truncated: boolean
   last_at: string
   last_from_me: boolean
   unread: number
@@ -132,7 +136,8 @@ function Inbox() {
                   </span>
                   <span className="msg-row-last dim">
                     {c.last_from_me ? t('messages.youPrefix') : ''}
-                    {c.last_body}
+                    {c.excerpt}
+                    {c.truncated ? '…' : ''}
                   </span>
                 </span>
                 {c.unread > 0 && (