diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3ab58bc8..9e8b4353 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@ the frozen-backend fallback mirror it for their toolchains.
 
 **Highlights**
 
+- Docker/server mode now requires an API key for remote changes and side-effectful admin checks across workers, engines, media tools, MCP, pronunciation, diagnostics, and LLM providers. (#1525)
+- The unified Support page no longer throws while opening a section in browsers or test environments without `scrollIntoView`. (#1525)
 - A faster, cleaner Dub workspace for multilingual production (#1489)
 - VoiceStudio now gives the app, desktop chrome, documentation, and package metadata one clear identity
 - A local-first creative studio: voice cloning, design, dubbing, dictation, stories, audiobooks, and transcription without a subscription meter
diff --git a/backend/api/dependencies.py b/backend/api/dependencies.py
index d3217d6e..25e6edaf 100644
--- a/backend/api/dependencies.py
+++ b/backend/api/dependencies.py
@@ -6,7 +6,10 @@ composed at the route or router level without surprises.
 
 Currently exposed:
 - `require_loopback`: 403 unless the request came from a loopback origin
-  (bypassed in explicit server mode — see `_server_mode`).
+  (read-only bootstrap is allowed in explicit server mode; mutations still
+  require the admin API key — see `_server_mode`).
+- `require_admin`: method-aware admin gate for privileged routers.
+- `require_admin_action`: strict admin gate for side-effectful GET actions.
 - `require_native_access`: true-loopback-only access to the host filesystem;
   unlike `require_loopback`, it is never bypassed by server mode.
 - `ws_remote_authorized`: whether a WebSocket handshake from a non-loopback
@@ -50,7 +53,7 @@ def _trusted_networks():
 
 def is_loopback(host):
     """True loopback address only (127.0.0.1, ::1, localhost) — NOT a trusted
-    network. Admin gates (``require_loopback`` → ``/system/set-env``,
+    network. Admin gates (``require_admin`` → ``/system/set-env``,
     ``/api/settings/*``) use this so a trusted-network CIDR exempts consumption
     (TTS / dictation) but never the RCE-class admin surface."""
     return host in _LOOPBACK_HOSTS
@@ -74,6 +77,7 @@ def is_local_host(host):
     return any(ip in net for net in _trusted_networks())
 
 _TRUTHY = frozenset({"1", "true", "yes", "on"})
+_READ_ONLY_METHODS = frozenset({"GET", "HEAD", "OPTIONS"})
 
 
 def _server_mode() -> bool:
@@ -96,6 +100,34 @@ def _server_mode() -> bool:
     return os.environ.get("OMNIVOICE_SERVER_MODE", "").strip().lower() in _TRUTHY
 
 
+def remote_api_key() -> str | None:
+    """The normalized remote-backend bearer key, or None when remote mode is
+    off. Surrounding whitespace is configuration noise, never a valid secret.
+    Read at call time so tests can monkeypatch the environment."""
+    return os.environ.get("OMNIVOICE_API_KEY", "").strip() or None
+
+
+def presented_api_key(connection) -> str:
+    """Return the first non-empty normalized API key on an HTTP/WS connection.
+
+    Authorization wins over query, which wins over cookie. Each channel is
+    stripped before fallback so whitespace in a higher-priority channel cannot
+    shadow a valid lower-priority credential.
+    """
+    headers = getattr(connection, "headers", None) or {}
+    query = getattr(connection, "query_params", None) or {}
+    cookies = getattr(connection, "cookies", None) or {}
+
+    auth = headers.get("authorization", "")
+    supplied = auth[7:].strip() if auth.lower().startswith("bearer ") else ""
+    if supplied:
+        return supplied
+    supplied = (query.get("api_key") or "").strip()
+    if supplied:
+        return supplied
+    return (cookies.get("ov_key") or "").strip()
+
+
 def _configured_pin(request) -> str | None:
     """The active share PIN (``app.state.network_share.pin``) or None. Read via
     getattr so a bare Request stub (or a request that hit before lifespan set
@@ -107,10 +139,13 @@ def _configured_pin(request) -> str | None:
 
 
 def _admin_credential_configured(request) -> bool:
-    """Whether the operator has set ANY credential gate — the remote API key or
-    a share PIN. When neither is set, server mode leaves admin open (the Docker
-    issue #261 flow the image depends on)."""
-    if os.environ.get("OMNIVOICE_API_KEY"):
+    """Whether an API key or share PIN is configured.
+
+    The PIN cannot authorize admin access, but its presence means the operator
+    opted out of bare-server discovery. Remote admin then remains closed until
+    they configure and present the long API key.
+    """
+    if remote_api_key():
         return True
     return bool(_configured_pin(request))
 
@@ -129,17 +164,10 @@ def _request_presents_admin_credential(request) -> bool:
     admin. Net: remote admin in server mode requires the API key; a PIN-only
     deployment keeps admin loopback-only. getattr-defensive so a minimal Request
     stub never raises."""
-    api_key = os.environ.get("OMNIVOICE_API_KEY") or ""
+    api_key = remote_api_key() or ""
     if not api_key:
         return False
-    headers = getattr(request, "headers", None) or {}
-    query = getattr(request, "query_params", None) or {}
-    cookies = getattr(request, "cookies", None) or {}
-
-    auth = headers.get("authorization", "")
-    supplied = auth[7:].strip() if auth.lower().startswith("bearer ") else ""
-    if not supplied:
-        supplied = query.get("api_key") or cookies.get("ov_key") or ""
+    supplied = presented_api_key(request)
     return bool(supplied and secrets.compare_digest(supplied, api_key))
 
 
@@ -163,9 +191,9 @@ def require_loopback(request: Request) -> None:
     unenforceable, so the gate can't require true loopback. It then applies the
     admin-credential rule instead:
 
-    - No credential configured (no API key, no PIN) → open, matching the #261
-      Docker flow where the operator reaches ``/system/*`` off the bridge
-      gateway with nothing set.
+    - No credential configured (no API key, no PIN) → read-only requests are
+      open, matching the #261 Docker bootstrap flow. State-changing requests
+      fail closed even if a route accidentally kept this legacy dependency.
     - A credential IS configured → the request must present the **API key**.
       This keeps the two-tier privilege model intact under server mode:
       ``OMNIVOICE_TRUSTED_NETWORKS`` is a *consumption* exemption
@@ -173,14 +201,20 @@ def require_loopback(request: Request) -> None:
       NEVER by itself unlock the admin surface (``/system/set-env`` — RCE-class —
       and ``/api/settings/*``). The 6-digit share PIN is a consumption credential
       too and does not gate admin, so a PIN-only deployment keeps admin
-      loopback-only; remote admin requires the (long) API key. A LAN client in a
-      trusted CIDR — or one holding only the PIN — gets 403 here even though it
-      sails through the consumption gates. See docs/api-auth.md (#1213).
+      loopback-only; remote admin requires the long API key. See
+      docs/api-auth.md (#1213).
     """
     host = request.client.host if request.client else None
     if is_loopback(host):
         return
     if _server_mode():
+        method = str(getattr(request, "method", "GET")).upper()
+        if method not in _READ_ONLY_METHODS:
+            # Defense in depth. Privileged routers should declare
+            # ``require_admin`` directly, but a missed migration must not turn
+            # into an unauthenticated Docker write primitive.
+            require_admin(request)
+            return
         if not _admin_credential_configured(request):
             return
         if _request_presents_admin_credential(request):
@@ -206,14 +240,29 @@ def require_admin(request: Request) -> None:
         return
     if _server_mode():
         method = str(getattr(request, "method", "GET")).upper()
-        read_only = method in {"GET", "HEAD", "OPTIONS"}
-        if read_only and not os.environ.get("OMNIVOICE_API_KEY", "").strip():
+        read_only = method in _READ_ONLY_METHODS
+        if read_only and not _admin_credential_configured(request):
             return
         if _request_presents_admin_credential(request):
             return
     raise HTTPException(status_code=403, detail="loopback origin or admin API key required")
 
 
+def require_admin_action(request: Request) -> None:
+    """Gate an administrative action even when its HTTP method is read-only.
+
+    A small number of legacy GET endpoints have real side effects. For example,
+    an engine health check may spawn a sidecar process. Such routes cannot use
+    :func:`require_admin`'s bare-server discovery exception.
+    """
+    host = request.client.host if request.client else None
+    if is_loopback(host):
+        return
+    if _server_mode() and _request_presents_admin_credential(request):
+        return
+    raise HTTPException(status_code=403, detail="loopback origin or admin API key required")
+
+
 def require_desktop(request: Request) -> None:
     """Gate capabilities that may select or execute host filesystem paths.
 
@@ -232,9 +281,10 @@ def require_local(request: Request) -> None:
     trusted network. The consumption-tier companion to :func:`require_loopback`:
     use on routes a trusted-network client (LAN/proxy) should reach without a PIN
     or API key — e.g. the dictation model/prefs endpoints that pair with the
-    dictation WebSocket. Admin routes stay on :func:`require_loopback`.
+    dictation WebSocket. Admin routes stay on :func:`require_admin`.
 
-    In server mode the gate is a no-op (same as :func:`require_loopback`)."""
+    In server mode this consumption gate is a no-op. Admin dependencies remain
+    method-aware and independent from this exemption."""
     host = request.client.host if request.client else None
     if is_local_host(host):
         return
@@ -256,12 +306,6 @@ def require_native_access(request: Request) -> None:
         raise HTTPException(status_code=403, detail="native filesystem access requires loopback origin")
 
 
-def remote_api_key() -> str | None:
-    """The remote-backend bearer key (Wave 2.3), or None when remote mode is
-    off. Read at call time so tests can monkeypatch the env."""
-    return os.environ.get("OMNIVOICE_API_KEY") or None
-
-
 def ws_remote_authorized(websocket) -> bool:
     """Whether a WebSocket handshake presents the remote API key.
 
@@ -273,12 +317,4 @@ def ws_remote_authorized(websocket) -> bool:
     key = remote_api_key()
     if not key:
         return False
-    auth = websocket.headers.get("authorization", "")
-    supplied = auth[7:].strip() if auth.lower().startswith("bearer ") else ""
-    if not supplied:
-        supplied = (
-            websocket.query_params.get("api_key")
-            or websocket.cookies.get("ov_key")
-            or ""
-        )
-    return secrets.compare_digest(supplied, key)
+    return secrets.compare_digest(presented_api_key(websocket), key)
diff --git a/backend/api/routers/capture_ws.py b/backend/api/routers/capture_ws.py
index 2bc1be24..c021087e 100644
--- a/backend/api/routers/capture_ws.py
+++ b/backend/api/routers/capture_ws.py
@@ -153,8 +153,8 @@ def _select_sherpa_spec(websocket: WebSocket):
 async def ws_transcribe(websocket: WebSocket):
     """Stream audio in, get partial + final transcription out."""
     # Loopback origin guard — refuse anything not from 127.0.0.1, ::1, or
-    # localhost. HTTP routers use Depends(require_loopback) at router level;
-    # WebSocket dependency injection differs across FastAPI versions, so we
+    # localhost. Privileged HTTP routers use Depends(require_admin) at router
+    # level; WebSocket dependency injection differs across FastAPI versions, so we
     # inline the check before accept(). Without it, any local process could
     # stream the user's microphone over this endpoint.
     # Wave 2.3 (remote backend): a non-loopback client that presents the
diff --git a/backend/api/routers/engines.py b/backend/api/routers/engines.py
index 1570c6d6..0b0cdd6f 100644
--- a/backend/api/routers/engines.py
+++ b/backend/api/routers/engines.py
@@ -25,7 +25,7 @@ from huggingface_hub import utils as hf_utils
 from huggingface_hub.errors import HFValidationError
 from pydantic import BaseModel
 
-from api.dependencies import require_loopback
+from api.dependencies import require_admin, require_admin_action, require_desktop
 from core import prefs
 from services import tts_backend, asr_backend, llm_backend, translation_engines
 from services.audio_dsp import list_effect_presets
@@ -113,7 +113,10 @@ def list_translation_engines():
     }
 
 
-@router.post("/engines/translation/{engine_id}/install")
+@router.post(
+    "/engines/translation/{engine_id}/install",
+    dependencies=[Depends(require_admin)],
+)
 async def install_translation_engine(engine_id: str):
     entry = translation_engines.get_engine(engine_id)
     if not entry:
@@ -149,7 +152,10 @@ async def install_translation_engine(engine_id: str):
     }
 
 
-@router.delete("/engines/translation/{engine_id}")
+@router.delete(
+    "/engines/translation/{engine_id}",
+    dependencies=[Depends(require_admin)],
+)
 async def uninstall_translation_engine(engine_id: str):
     entry = translation_engines.get_engine(engine_id)
     if not entry:
@@ -188,15 +194,16 @@ async def uninstall_translation_engine(engine_id: str):
 # POST /engines/sonitranslate/install). Mirrors the
 # /engines/translation/{engine_id}/install namespace pattern.
 #
-# Loopback-gated: installing spawns subprocesses (git/uv) and writes to the
-# data directory — only the local desktop frontend may trigger it. The job
-# runs fine in packaged builds: the venv lives under the user data dir, not
-# inside the signed app bundle, and uv resolves via OMNIVOICE_BUNDLED_UV/PATH.
+# Desktop-only: installing spawns git/uv against mutable source and writes an
+# editable environment. An API key does not make that supply-chain path safe to
+# trigger remotely. The job runs fine in packaged builds: the venv lives under
+# the user data dir, not inside the signed app bundle, and uv resolves via
+# OMNIVOICE_BUNDLED_UV/PATH.
 
 
 @router.post(
     "/engines/sidecar/{engine_id}/install",
-    dependencies=[Depends(require_loopback)],
+    dependencies=[Depends(require_admin), Depends(require_desktop)],
 )
 def install_sidecar_engine(engine_id: str):
     """Start (or report) the one-click install for a sidecar engine.
@@ -222,7 +229,7 @@ def install_sidecar_engine(engine_id: str):
 
 @router.get(
     "/engines/sidecar/{engine_id}/install/status",
-    dependencies=[Depends(require_loopback)],
+    dependencies=[Depends(require_admin)],
 )
 def sidecar_install_status(engine_id: str):
     """Step-by-step status of the sidecar install job (poll while running).
@@ -243,7 +250,7 @@ def sidecar_install_status(engine_id: str):
 
 @router.delete(
     "/engines/sidecar/{engine_id}/install",
-    dependencies=[Depends(require_loopback)],
+    dependencies=[Depends(require_admin)],
 )
 def uninstall_sidecar_engine(engine_id: str):
     """Remove an app-managed sidecar install (checkout + venv + weights) and
@@ -274,8 +281,8 @@ def uninstall_sidecar_engine(engine_id: str):
 # frame. Result includes wall-clock latency so the UI can render
 # "1234 ms — pong" inline next to the button.
 #
-# Loopback-gated (T-02-13): only the local desktop frontend may trigger
-# a sidecar spawn through this endpoint.
+# Admin-gated (T-02-13): only the local desktop frontend or an authenticated
+# server-mode administrator may trigger a sidecar spawn through this endpoint.
 
 # Engine instances cached for the lifetime of the FastAPI process so that
 # repeated health checks don't spawn a new SubprocessBackend (each spawn
@@ -311,7 +318,7 @@ def _resolve_engine_class(engine_id: str):
 
 @router.get(
     "/engines/{engine_id}/health",
-    dependencies=[Depends(require_loopback)],
+    dependencies=[Depends(require_admin_action)],
 )
 def engine_health(engine_id: str):
     """Spawn-and-ping a SubprocessBackend; ``is_available()`` for the rest.
@@ -385,7 +392,7 @@ def engine_health(engine_id: str):
 #     hanging the Settings panel. The orphaned worker is best-effort daemon.
 #   * A process-wide lock serialises self-tests so a click-storm can't stack
 #     concurrent model loads.
-#   * Only ever on user click (POST) — never on Settings load. Loopback-gated.
+#   * Only ever on user click (POST) — never on Settings load. Admin-gated.
 
 # Deliberately short + ASCII so the synth stays CPU-cheap and the phrase never
 # trips the no-hardcoded-CJK guard.
@@ -452,7 +459,7 @@ class SelfTestResponse(BaseModel):
 @router.post(
     "/engines/{engine_id}/selftest",
     response_model=SelfTestResponse,
-    dependencies=[Depends(require_loopback)],
+    dependencies=[Depends(require_admin)],
 )
 def engine_selftest(engine_id: str):
     """Run a bounded, real synthesis on an available in-process TTS engine.
@@ -551,7 +558,11 @@ class SelectEngineResponse(BaseModel):
     routing_reason: str | None = None
 
 
-@router.post("/engines/select", response_model=SelectEngineResponse)
+@router.post(
+    "/engines/select",
+    response_model=SelectEngineResponse,
+    dependencies=[Depends(require_admin)],
+)
 def select_engine(req: SelectEngineRequest):
     """Persist a family's engine pick to prefs.json. Refuses unknown backends,
     backends whose deps aren't installed, AND backends that cannot run on THIS
diff --git a/backend/api/routers/mcp_bindings.py b/backend/api/routers/mcp_bindings.py
index c1cf7aae..602cd3b5 100644
--- a/backend/api/routers/mcp_bindings.py
+++ b/backend/api/routers/mcp_bindings.py
@@ -9,13 +9,13 @@ from __future__ import annotations
 from fastapi import APIRouter, Depends, HTTPException
 from pydantic import BaseModel, Field
 
-from api.dependencies import require_loopback
+from api.dependencies import require_admin
 from services import mcp_bindings
 
 router = APIRouter(
     prefix="/api/mcp",
     tags=["mcp"],
-    dependencies=[Depends(require_loopback)],
+    dependencies=[Depends(require_admin)],
 )
 
 
diff --git a/backend/api/routers/media_tools.py b/backend/api/routers/media_tools.py
index 770cd865..50e5a181 100644
--- a/backend/api/routers/media_tools.py
+++ b/backend/api/routers/media_tools.py
@@ -12,10 +12,10 @@ import logging
 from fastapi import APIRouter, Depends, HTTPException
 from pydantic import BaseModel
 
-from api.dependencies import require_loopback
+from api.dependencies import require_admin
 
 logger = logging.getLogger("omnivoice.api")
-router = APIRouter(dependencies=[Depends(require_loopback)])
+router = APIRouter(dependencies=[Depends(require_admin)])
 
 
 class CustomPathRequest(BaseModel):
diff --git a/backend/api/routers/pronunciation.py b/backend/api/routers/pronunciation.py
index 7db9759f..193f9c44 100644
--- a/backend/api/routers/pronunciation.py
+++ b/backend/api/routers/pronunciation.py
@@ -7,7 +7,7 @@ CRUD for the DB-backed, per-language pronunciation dictionary the
 before synthesis (see ``services/pronunciation.apply_pronunciation`` and the
 generate path), so a saved entry actually changes the audio on every engine.
 
-Endpoints (loopback-only, like the dictation router):
+Endpoints (admin-gated; loopback or authenticated server mode):
     GET    /pronunciation              → list every entry
     POST   /pronunciation              → create one entry
     PUT    /pronunciation/{entry_id}   → update an entry (partial)
@@ -30,12 +30,12 @@ from typing import List, Optional
 from fastapi import APIRouter, Depends, HTTPException
 from pydantic import BaseModel
 
-from api.dependencies import require_loopback
+from api.dependencies import require_admin
 from core.db import db_conn
 from services.pronunciation import apply_pronunciation, entries_for_language
 
 logger = logging.getLogger("omnivoice.pronunciation")
-router = APIRouter()
+router = APIRouter(dependencies=[Depends(require_admin)])
 
 _VALID_TYPES = ("respelling", "ipa", "cmu")
 _ALL_LANG = "*"
@@ -133,7 +133,7 @@ class PronImportRequest(BaseModel):
 # ── CRUD ─────────────────────────────────────────────────────────────────────
 
 
-@router.get("/pronunciation", dependencies=[Depends(require_loopback)])
+@router.get("/pronunciation")
 def list_entries():
     with db_conn() as conn:
         rows = conn.execute(
@@ -143,7 +143,7 @@ def list_entries():
     return [_row_to_dict(r) for r in rows]
 
 
-@router.post("/pronunciation", dependencies=[Depends(require_loopback)])
+@router.post("/pronunciation")
 def create_entry(entry: PronEntry):
     term = entry.term.strip()
     if not term:
@@ -171,7 +171,7 @@ def create_entry(entry: PronEntry):
     return _row_to_dict(row)
 
 
-@router.put("/pronunciation/{entry_id}", dependencies=[Depends(require_loopback)])
+@router.put("/pronunciation/{entry_id}")
 def update_entry(entry_id: str, patch: PronEntryUpdate):
     with db_conn() as conn:
         existing = conn.execute(
@@ -226,7 +226,7 @@ def update_entry(entry_id: str, patch: PronEntryUpdate):
     return _row_to_dict(row)
 
 
-@router.delete("/pronunciation/{entry_id}", dependencies=[Depends(require_loopback)])
+@router.delete("/pronunciation/{entry_id}")
 def delete_entry(entry_id: str):
     with db_conn() as conn:
         cur = conn.execute("DELETE FROM pronunciation_entries WHERE id = ?", (entry_id,))
@@ -236,7 +236,7 @@ def delete_entry(entry_id: str):
 # ── Dry-run + import/export ───────────────────────────────────────────────────
 
 
-@router.post("/pronunciation/test", dependencies=[Depends(require_loopback)])
+@router.post("/pronunciation/test")
 def test_substitution(req: PronTestRequest):
     """Show the post-substitution text for ``req.text`` — no model call.
 
@@ -258,7 +258,7 @@ def test_substitution(req: PronTestRequest):
     }
 
 
-@router.get("/pronunciation/export", dependencies=[Depends(require_loopback)])
+@router.get("/pronunciation/export")
 def export_entries():
     """Every entry as a JSON-serializable list (round-trips ``/import``)."""
     with db_conn() as conn:
@@ -273,7 +273,7 @@ def export_entries():
     ]}
 
 
-@router.post("/pronunciation/import", dependencies=[Depends(require_loopback)])
+@router.post("/pronunciation/import")
 def import_entries(req: PronImportRequest):
     """Bulk-add entries. ``replace=true`` clears the table first.
 
diff --git a/backend/api/routers/settings.py b/backend/api/routers/settings.py
index e2591801..70d33bf5 100644
--- a/backend/api/routers/settings.py
+++ b/backend/api/routers/settings.py
@@ -20,7 +20,7 @@ from fastapi import APIRouter, Depends, HTTPException, Query
 from pydantic import BaseModel, Field
 
 from core.logging_utils import log_safe
-from api.dependencies import require_admin
+from api.dependencies import require_admin, require_admin_action
 
 logger = logging.getLogger("omnivoice.api.settings")
 
@@ -92,8 +92,8 @@ def get_hf_token_state(fresh: bool = Query(False)):
 
 
 # ── Performance settings (INST-12) ────────────────────────────────────────
-# Threat T-02-04: same loopback guard as the hf-token endpoints via the
-# router-level `require_loopback` dep.
+# Threat T-02-04: same admin guard as the hf-token endpoints via the
+# router-level `require_admin` dep.
 
 
 _TORCH_COMPILE_KEY = "perf.torch_compile_disabled"
@@ -481,7 +481,10 @@ def _local_models(base_url: str, api_key: str):
         return None
 
 
-@router.get("/llm-providers/{provider_id}/models")
+@router.get(
+    "/llm-providers/{provider_id}/models",
+    dependencies=[Depends(require_admin_action)],
+)
 def list_llm_provider_models(provider_id: str):
     """List model ids the provider's key can access (OpenAI-compat /models).
 
diff --git a/backend/api/routers/system.py b/backend/api/routers/system.py
index 48e9547a..40bea2e8 100644
--- a/backend/api/routers/system.py
+++ b/backend/api/routers/system.py
@@ -11,7 +11,7 @@ from core.prefs import set_ as prefs_set, delete as prefs_delete
 from services import network_share
 from services import tailscale as _tailscale
 from api.schemas import SysinfoResponse, SystemInfoResponse, ModelStatusResponse
-from api.dependencies import is_loopback, require_admin
+from api.dependencies import is_loopback, require_admin, require_admin_action
 from fastapi.responses import FileResponse, StreamingResponse
 import torch
 import shutil
@@ -1089,7 +1089,10 @@ async def diagnostic_bundle(network: bool = Query(False, description="Include th
 # ── Self-check diagnostics ────────────────────────────────────────────────
 
 
-@router.get("/system/diagnose")
+@router.get(
+    "/system/diagnose",
+    dependencies=[Depends(require_admin_action)],
+)
 async def system_diagnose(
     network: bool = Query(True, description="Include the HuggingFace hub reachability probe"),
     deep: bool = Query(False, description="Also load the active engine and synthesize a short utterance (may cold-load the model — minutes on first run)"),
diff --git a/backend/api/routers/workers.py b/backend/api/routers/workers.py
index 554e6ebb..3136520c 100644
--- a/backend/api/routers/workers.py
+++ b/backend/api/routers/workers.py
@@ -28,7 +28,7 @@ import logging
 from fastapi import APIRouter, Depends, HTTPException, Request
 from pydantic import BaseModel, Field
 
-from api.dependencies import require_loopback
+from api.dependencies import require_admin
 from worker import registry, routing, service
 
 logger = logging.getLogger("omnivoice.worker")
@@ -39,9 +39,9 @@ logger = logging.getLogger("omnivoice.worker")
 # the task's own deadline does.
 _DISCONNECT_POLL_SECONDS = 1.0
 
-# Management is loopback-only: these endpoints mint join tokens and revoke
-# machines, so they follow the same rule as the app's other privileged routes.
-router = APIRouter(prefix="/workers", tags=["workers"], dependencies=[Depends(require_loopback)])
+# Management is admin-gated: these endpoints mint join tokens and revoke
+# machines, so Docker writes require the API key while desktop stays loopback.
+router = APIRouter(prefix="/workers", tags=["workers"], dependencies=[Depends(require_admin)])
 
 
 class EnableRequest(BaseModel):
diff --git a/backend/main.py b/backend/main.py
index 64a14c4f..d88a45ed 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -375,7 +375,11 @@ from services.model_manager import (
 )
 from services import network_share
 
-from api.dependencies import is_local_host  # loopback + OMNIVOICE_TRUSTED_NETWORKS
+from api.dependencies import (  # loopback + OMNIVOICE_TRUSTED_NETWORKS
+    is_local_host,
+    presented_api_key,
+    remote_api_key,
+)
 
 from api.routers import (
     system,
@@ -1197,7 +1201,7 @@ class BearerKeyMiddleware:
     async def __call__(self, scope, receive, send):
         if scope["type"] not in ("http", "websocket"):
             return await self.app(scope, receive, send)
-        key = os.environ.get("OMNIVOICE_API_KEY") or ""
+        key = remote_api_key() or ""
         if not key:
             return await self.app(scope, receive, send)
         client = scope["client"][0] if scope.get("client") else None
@@ -1212,10 +1216,7 @@ class BearerKeyMiddleware:
         from starlette.requests import HTTPConnection
 
         conn = HTTPConnection(scope)
-        auth = conn.headers.get("authorization", "")
-        supplied = auth[7:].strip() if auth.lower().startswith("bearer ") else ""
-        if not supplied:
-            supplied = conn.query_params.get("api_key") or conn.cookies.get("ov_key") or ""
+        supplied = presented_api_key(conn)
 
         if not secrets.compare_digest(supplied, key):
             if scope["type"] == "websocket":
diff --git a/docs/api-auth.md b/docs/api-auth.md
index cc68ae84..5b1bcb26 100644
--- a/docs/api-auth.md
+++ b/docs/api-auth.md
@@ -196,10 +196,11 @@ time, so in production **restart the backend** to apply a change. Default empty
 ## Admin routes and server mode
 
 Admin routes — `/system/*` (including `set-env`, **RCE-class**),
-`/api/settings/*`, engine install/uninstall, media tools, MCP bindings — sit on
-a stricter gate (`require_admin`, `backend/api/dependencies.py`) than
-consumption. On the desktop build they are **true-loopback-only**: no PIN, key,
-or trusted network reaches them from another machine.
+`/api/settings/*`, engine selection/install/uninstall, media tools, MCP
+bindings, pronunciation settings, and remote-worker management — sit on a
+stricter gate (`require_admin`, `backend/api/dependencies.py`) than consumption.
+On the desktop build they are **true-loopback-only**: no PIN, key, or trusted
+network reaches them from another machine.
 
 In **server mode** (`OMNIVOICE_SERVER_MODE=1`, the Docker image) the loopback
 origin is unenforceable — NAT rewrites the source and even a
@@ -207,16 +208,22 @@ origin is unenforceable — NAT rewrites the source and even a
 requirement is dropped (issue #261, else the operator is 403'd out of their own
 `/system/*`). It is replaced by a **credential rule**, not removed:
 
-- **No API key configured** → read-only admin discovery remains available for
-  the bare Docker bootstrap flow, but `POST`/`PUT`/`PATCH`/`DELETE` requests are
-  denied. Set `OMNIVOICE_API_KEY` before changing settings remotely.
-- **A credential is configured** → admin requires the **API key** (`Authorization:
+- **No credential configured** (neither API key nor share PIN) → read-only
+  admin discovery remains available for the bare Docker bootstrap flow, but
+  `POST`/`PUT`/`PATCH`/`DELETE` requests are denied. Side-effectful GET actions
+  are denied too: engine health may start a sidecar, deep diagnostics may load
+  a model, and LLM provider discovery makes a request with the saved provider
+  credential. Set `OMNIVOICE_API_KEY` before changing settings or triggering
+  those actions remotely.
+- **An API key is configured** → admin requires that **API key** (`Authorization:
   Bearer` / `?api_key` / `ov_key` cookie), or genuine loopback. The **6-digit
   share PIN does not gate admin** (it is brute-forceable), and trusted-network
   membership never does either. A **PIN-only** server-mode deployment therefore
-  allows remote read-only discovery but blocks remote mutations; remote writes
-  require the long API key. Discovery never returns the share PIN itself; only
-  loopback or a caller already authenticated with the API key can read it.
+  keeps admin routes loopback-only; remote admin requires the long API key.
+
+Managed sidecar installation remains true-loopback-only even with an API key.
+Its installer fetches mutable source and creates an editable environment, so it
+must be run directly on that machine until the source supply chain is pinned.
 
 Host paths are never selected through HTTP. The native Tauri process validates
 model-cache and export destinations plus custom FFmpeg/FFprobe binaries, writes
diff --git a/docs/remote-workers.md b/docs/remote-workers.md
index 5a2b1e4c..d4aeefaa 100644
--- a/docs/remote-workers.md
+++ b/docs/remote-workers.md
@@ -7,6 +7,12 @@ This is **opt-in and off by default**. Until you turn it on and approve a
 worker, nothing leaves your computer, no port is opened, and the app behaves
 exactly as it did before.
 
+Worker management is an admin surface. In Docker/server mode, viewing status
+works during bare bootstrap, but joining, enabling, approving, issuing keys,
+disconnecting, or removing machines remotely requires `OMNIVOICE_API_KEY`.
+The share PIN and trusted-network exemptions authorize playback, not worker
+administration.
+
 > **Not the same as [Remote backend](remote-gpu.md).** That points this app at
 > a backend running somewhere else, so the whole app — your projects, your
 > voices, your history — lives on that machine. This keeps everything here and
@@ -157,10 +163,11 @@ The Dictation surface states that it always uses this machine without showing
 the generic "not ported yet" notice.
 
 For protocol development, a task can also be placed by hand with
-`POST /workers/tasks` — a **development-only** endpoint. It is loopback-only,
+`POST /workers/tasks` — a **development-only** endpoint. It is admin-gated,
 sits behind the same opt-in as everything else here, takes a mandatory
-deadline, submits one task and waits for it. It is not a stable API and goes
-away once generation routes itself.
+deadline, submits one task and waits for it. On desktop that means loopback;
+in server mode a remote caller needs `OMNIVOICE_API_KEY`. It is not a stable
+API and goes away once generation routes itself.
 
 ## How work is placed
 
diff --git a/frontend/src/pages/SupportPage.jsx b/frontend/src/pages/SupportPage.jsx
index 04ce8285..99f7f9e1 100644
--- a/frontend/src/pages/SupportPage.jsx
+++ b/frontend/src/pages/SupportPage.jsx
@@ -523,9 +523,10 @@ export default function SupportPage({ onBack, initialView = 'support' }) {
     const id = SECTION_IDS[initialView] || SECTION_IDS.support;
     // rAF: the panel has to be laid out before an offset means anything.
     const frame = requestAnimationFrame(() => {
-      sectionRef.current
-        ?.querySelector(`#${id}`)
-        ?.scrollIntoView({ block: 'start', behavior: 'auto' });
+      const section = sectionRef.current?.querySelector(`#${id}`);
+      if (typeof section?.scrollIntoView === 'function') {
+        section.scrollIntoView({ block: 'start', behavior: 'auto' });
+      }
     });
     return () => cancelAnimationFrame(frame);
   }, [initialView]);
diff --git a/tests/backend/api/test_engines_route_shape.py b/tests/backend/api/test_engines_route_shape.py
index f7131222..90834274 100644
--- a/tests/backend/api/test_engines_route_shape.py
+++ b/tests/backend/api/test_engines_route_shape.py
@@ -66,7 +66,7 @@ def fresh_app(monkeypatch, tmp_path):
 def _client(app, host="127.0.0.1"):
     """TestClient anchored to a loopback (or non-loopback) client tuple.
 
-    `require_loopback` reads `request.client.host`; the default
+    The admin dependency reads `request.client.host`; the default
     TestClient tuple is `('testclient', 50000)` which the dep rejects.
     """
     from fastapi.testclient import TestClient
@@ -614,12 +614,56 @@ def test_engine_health_unknown_id(fresh_app):
     assert "unknown engine id" in r.json()["detail"]
 
 
-def test_engine_health_loopback_only(fresh_app):
-    """Non-loopback client tuple is rejected by require_loopback."""
+def test_engine_health_is_admin_gated(fresh_app):
+    """Non-loopback desktop traffic is rejected by require_admin."""
     client = _client(fresh_app, host="10.0.0.5")
     r = client.get("/engines/omnivoice/health")
     assert r.status_code == 403
-    assert r.json()["detail"] == "loopback origin required"
+    assert r.json()["detail"] == "loopback origin or admin API key required"
+
+
+def test_server_mode_engine_mutations_require_api_key(fresh_app, monkeypatch):
+    monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
+    monkeypatch.delenv("OMNIVOICE_API_KEY", raising=False)
+    client = _client(fresh_app, host="172.17.0.1")
+
+    requests = [
+        ("post", "/engines/translation/deep-translator/install", None),
+        ("delete", "/engines/translation/deep-translator", None),
+        ("post", "/engines/sidecar/indextts2/install", None),
+        ("delete", "/engines/sidecar/indextts2/install", None),
+        ("post", "/engines/omnivoice/selftest", None),
+        ("post", "/engines/select", {}),
+    ]
+    for method, path, body in requests:
+        response = client.request(method.upper(), path, json=body)
+        assert response.status_code == 403, path
+
+
+def test_server_mode_engine_health_requires_api_key(fresh_app, monkeypatch):
+    """Health is a GET but can spawn a sidecar, so it is not discovery."""
+    monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
+    monkeypatch.delenv("OMNIVOICE_API_KEY", raising=False)
+    client = _client(fresh_app, host="172.17.0.1")
+
+    response = client.get("/engines/omnivoice/health")
+
+    assert response.status_code == 403
+
+
+def test_server_mode_sidecar_install_stays_desktop_only(fresh_app, monkeypatch):
+    """An API key cannot remotely trigger the mutable-source installer."""
+    monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
+    monkeypatch.setenv("OMNIVOICE_API_KEY", "s3cret")
+    client = _client(fresh_app, host="172.17.0.1")
+
+    response = client.post(
+        "/engines/sidecar/indextts2/install",
+        headers={"authorization": "Bearer s3cret"},
+    )
+
+    assert response.status_code == 403
+    assert response.json()["detail"] == "desktop origin required"
 
 
 def test_engine_health_caches_instance_across_calls(fresh_app, monkeypatch):
@@ -747,10 +791,10 @@ def test_selftest_unknown_id_is_404(fresh_app):
     assert "unknown TTS engine id" in r.json()["detail"]
 
 
-def test_selftest_loopback_only(fresh_app):
+def test_selftest_is_admin_gated(fresh_app):
     r = _client(fresh_app, host="10.0.0.9").post("/engines/omnivoice/selftest")
     assert r.status_code == 403
-    assert r.json()["detail"] == "loopback origin required"
+    assert r.json()["detail"] == "loopback origin or admin API key required"
 
 
 def test_selftest_captures_synth_exception_without_500(fresh_app):
diff --git a/tests/backend/test_engine_spawn_token.py b/tests/backend/test_engine_spawn_token.py
index 054389ed..28bdc790 100644
--- a/tests/backend/test_engine_spawn_token.py
+++ b/tests/backend/test_engine_spawn_token.py
@@ -43,7 +43,7 @@ def fresh_app(monkeypatch, tmp_path):
 
 
 def _client(app):
-    """TestClient anchored to a loopback client tuple so require_loopback
+    """TestClient anchored to a loopback client tuple so require_admin
     treats requests as local. The default TestClient client tuple is
     ('testclient', 50000), which the dep rejects."""
     from fastapi.testclient import TestClient
@@ -78,7 +78,7 @@ def test_post_hf_token_loopback_succeeds(fresh_app, monkeypatch):
 
 def test_post_hf_token_non_loopback_returns_403(fresh_app):
     """A non-loopback origin (simulated via TestClient client tuple) is
-    rejected with 403 per the require_loopback dep."""
+    rejected with 403 per the require_admin dep."""
     from fastapi.testclient import TestClient
     with TestClient(fresh_app, client=("10.0.0.5", 12345)) as c:
         r = c.post("/api/settings/hf-token", json={"token": SAMPLE_TOKEN})
@@ -175,7 +175,7 @@ def test_get_hf_token_state_fresh_busts_whoami_cache(fresh_app, monkeypatch):
 
 
 def test_get_hf_token_state_loopback_only(fresh_app):
-    """GET state is on the same loopback-only router; non-loopback → 403."""
+    """GET state is on the same admin router; non-loopback desktop → 403."""
     from fastapi.testclient import TestClient
     with TestClient(fresh_app, client=("10.0.0.5", 12345)) as c:
         r = c.get("/api/settings/hf-token/state")
diff --git a/tests/probe/_boot_runner.py b/tests/probe/_boot_runner.py
index 7ac1720b..fd5e1ee3 100644
--- a/tests/probe/_boot_runner.py
+++ b/tests/probe/_boot_runner.py
@@ -77,7 +77,7 @@ def main() -> int:
         # Loopback security: a non-loopback origin must be rejected on system
         # routes. Use a bare client (no `with`) so we don't re-enter the app
         # lifespan — re-entry rebinds the module-level task queue to a new event
-        # loop and crashes. The require_loopback dependency only inspects
+        # loop and crashes. The require_admin dependency only inspects
         # request.client.host, which doesn't need lifespan state.
         nl = TestClient(app)  # default client host 'testclient' = non-loopback
         ctx["loopback_reject_status"] = nl.get("/system/info").status_code
diff --git a/tests/test_admin_route_policy.py b/tests/test_admin_route_policy.py
new file mode 100644
index 00000000..b41b98ed
--- /dev/null
+++ b/tests/test_admin_route_policy.py
@@ -0,0 +1,135 @@
+"""Static policy guard for server-mode administrative routes.
+
+The behavioural tests prove the dependencies themselves.  This file proves
+the dangerous routers are actually wired to the strict dependency; testing a
+perfect guard is worthless when a route imports the legacy one instead.
+"""
+
+from __future__ import annotations
+
+import ast
+from pathlib import Path
+
+import pytest
+
+
+ROOT = Path(__file__).resolve().parents[1]
+ROUTERS = ROOT / "backend" / "api" / "routers"
+
+
+def _tree(filename: str) -> ast.Module:
+    return ast.parse((ROUTERS / filename).read_text(encoding="utf-8"))
+
+
+def _router_assignment(tree: ast.Module) -> ast.expr:
+    for node in tree.body:
+        if not isinstance(node, ast.Assign):
+            continue
+        if not any(
+            isinstance(target, ast.Name) and target.id == "router"
+            for target in node.targets
+        ):
+            continue
+        return node.value
+    raise AssertionError("router assignment not found")
+
+
+def _route_decorators(tree: ast.Module, function_name: str) -> list[ast.expr]:
+    for node in tree.body:
+        if (
+            isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef))
+            and node.name == function_name
+        ):
+            return node.decorator_list
+    raise AssertionError(f"route function not found: {function_name}")
+
+
+def _dependency_names(nodes: ast.AST | list[ast.AST]) -> set[str]:
+    roots = nodes if isinstance(nodes, list) else [nodes]
+    names: set[str] = set()
+    for root in roots:
+        for node in ast.walk(root):
+            if not isinstance(node, ast.Call) or not node.args:
+                continue
+            if not isinstance(node.func, ast.Name) or node.func.id != "Depends":
+                continue
+            dependency = node.args[0]
+            if isinstance(dependency, ast.Name):
+                names.add(dependency.id)
+    return names
+
+
+def _mutating_route_functions(
+    tree: ast.Module,
+) -> list[ast.FunctionDef | ast.AsyncFunctionDef]:
+    mutating_methods = {"post", "put", "patch", "delete"}
+    functions = []
+    for node in tree.body:
+        if not isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef)):
+            continue
+        for decorator in node.decorator_list:
+            if not isinstance(decorator, ast.Call):
+                continue
+            route = decorator.func
+            if (
+                isinstance(route, ast.Attribute)
+                and isinstance(route.value, ast.Name)
+                and route.value.id == "router"
+                and route.attr in mutating_methods
+            ):
+                functions.append(node)
+                break
+    return functions
+
+
+@pytest.mark.parametrize(
+    "filename",
+    [
+        "mcp_bindings.py",
+        "media_tools.py",
+        "pronunciation.py",
+        "settings.py",
+        "system.py",
+        "workers.py",
+    ],
+)
+def test_privileged_router_uses_method_aware_admin_guard(filename):
+    dependencies = _dependency_names(_router_assignment(_tree(filename)))
+    assert "require_admin" in dependencies
+    assert "require_loopback" not in dependencies
+
+
+def test_every_mutating_engine_route_uses_method_aware_admin_guard():
+    functions = _mutating_route_functions(_tree("engines.py"))
+    assert functions
+    for function in functions:
+        dependencies = _dependency_names(function.decorator_list)
+        assert "require_admin" in dependencies, function.name
+        assert "require_loopback" not in dependencies, function.name
+
+
+def test_sidecar_install_status_uses_method_aware_admin_guard():
+    dependencies = _dependency_names(
+        _route_decorators(_tree("engines.py"), "sidecar_install_status")
+    )
+    assert "require_admin" in dependencies
+
+
+def test_managed_sidecar_install_stays_desktop_only():
+    dependencies = _dependency_names(
+        _route_decorators(_tree("engines.py"), "install_sidecar_engine")
+    )
+    assert {"require_admin", "require_desktop"} <= dependencies
+
+
+@pytest.mark.parametrize(
+    ("filename", "function_name"),
+    [
+        ("engines.py", "engine_health"),
+        ("settings.py", "list_llm_provider_models"),
+        ("system.py", "system_diagnose"),
+    ],
+)
+def test_side_effectful_get_requires_strict_admin_action(filename, function_name):
+    dependencies = _dependency_names(_route_decorators(_tree(filename), function_name))
+    assert "require_admin_action" in dependencies
diff --git a/tests/test_api.py b/tests/test_api.py
index fe12b1e0..2f591017 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -74,7 +74,7 @@ def client():
 
     `client=("127.0.0.1", 50000)` makes `request.client.host` resolve to a
     loopback address — required because `backend/api/routers/system.py` is
-    now gated by a router-level `require_loopback` dependency. Tests that
+    now gated by a router-level `require_admin` dependency. Tests that
     deliberately exercise the non-loopback rejection path build their own
     plain `TestClient(app)` (which defaults to host='testclient').
     """
@@ -551,7 +551,7 @@ class TestStreamingTTS:
 def test_set_env_rejects_non_loopback():
     """A TestClient that does NOT override `client=` sets
     `request.client.host = 'testclient'` (non-loopback). The router-level
-    `require_loopback` dependency must return 403 and must NOT mutate
+    `require_admin` dependency must return 403 and must NOT mutate
     os.environ. NOTE: the project-wide `client` fixture is now built with a
     loopback override so most tests see protected routes — this test
     instantiates its own plain client to exercise the rejection path."""
diff --git a/tests/test_bearer_middleware.py b/tests/test_bearer_middleware.py
index 699df0dd..42054512 100644
--- a/tests/test_bearer_middleware.py
+++ b/tests/test_bearer_middleware.py
@@ -30,6 +30,24 @@ def test_inert_without_env(monkeypatch):
     assert c.get("/health").status_code == 200
 
 
+def test_whitespace_only_env_is_not_an_api_key(monkeypatch):
+    monkeypatch.setenv("OMNIVOICE_API_KEY", "   ")
+    c = _client()
+    response = c.get("/v1/audio/voices")
+    assert response.status_code == 200
+    assert isinstance(response.json().get("voices"), list)
+
+
+def test_whitespace_query_does_not_shadow_valid_cookie(key_env):
+    c = _client()
+    c.cookies.set("ov_key", key_env)
+
+    response = c.get("/v1/audio/voices?api_key=%20%20%20")
+
+    assert response.status_code == 200
+    assert isinstance(response.json().get("voices"), list)
+
+
 def test_loopback_bypasses_key(key_env):
     c = _client(("127.0.0.1", 1))
     assert c.get("/system/info").status_code == 200
diff --git a/tests/test_generate_engine.py b/tests/test_generate_engine.py
index cb36ef8f..ae3ab57c 100644
--- a/tests/test_generate_engine.py
+++ b/tests/test_generate_engine.py
@@ -84,7 +84,7 @@ def client():
     # module's event loop and broke teardown when the full suite mixes it
     # with the non-lifespan TestClients every other test file uses
     # (test_api.py pattern). Loopback client addr: required by the
-    # router-level require_loopback dependency.
+    # router-level require_admin dependency.
     from fastapi.testclient import TestClient
     from main import app
 
diff --git a/tests/test_loopback_server_mode.py b/tests/test_loopback_server_mode.py
index 0738a31f..775fafb2 100644
--- a/tests/test_loopback_server_mode.py
+++ b/tests/test_loopback_server_mode.py
@@ -1,9 +1,9 @@
-"""`require_loopback` gate contract (issue #261).
+"""Server-mode origin and admin gate contracts (issue #261).
 
 The gate must stay strict on the desktop build (non-loopback → 403, which is the
-PR #81 trust boundary), but become a no-op in the headless Docker server mode,
-where Docker's NAT makes the loopback origin unenforceable and exposure is
-governed by the port mapping + the share PIN instead.
+PR #81 trust boundary). Docker NAT makes the host operator appear non-loopback,
+so bare server mode keeps read-only discovery open while every mutation still
+requires the long admin API key.
 """
 from types import SimpleNamespace
 
@@ -30,6 +30,10 @@ def require_admin(*args, **kwargs):
     return _dependency("require_admin")(*args, **kwargs)
 
 
+def require_admin_action(*args, **kwargs):
+    return _dependency("require_admin_action")(*args, **kwargs)
+
+
 def require_desktop(*args, **kwargs):
     return _dependency("require_desktop")(*args, **kwargs)
 
@@ -88,7 +92,7 @@ def test_falsey_server_mode_keeps_gate_strict(monkeypatch, val):
 # Trusted local networks (OMNIVOICE_TRUSTED_NETWORKS) — issue #1170.
 # A self-hoster can name CIDRs treated as trusted by the CONSUMPTION gates
 # (PIN/API-key/WS), so a LAN or reverse proxy is exempted. Admin gates
-# (require_loopback) stay true-loopback-only — two-tier privilege model.
+# (require_admin) stay true-loopback-only — two-tier privilege model.
 
 
 @pytest.mark.parametrize("host", ["127.0.0.1", "::1", "localhost"])
@@ -178,12 +182,101 @@ def _req_full(host, *, headers=None, query=None, cookies=None, pin=None, method=
     )
 
 
+@pytest.mark.parametrize("method", ["POST", "PUT", "PATCH", "DELETE"])
+def test_legacy_loopback_guard_fails_closed_for_server_mode_mutations(
+    monkeypatch, method
+):
+    """A stale route guard must not reopen writes in a bare Docker server.
+
+    ``require_admin`` is the explicit dependency for privileged routers, but
+    this fallback closes the whole bug class: a future mutation that
+    accidentally keeps ``require_loopback`` still requires the long API key.
+    """
+    monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
+    monkeypatch.delenv("OMNIVOICE_API_KEY", raising=False)
+
+    with pytest.raises(HTTPException) as exc:
+        require_loopback(_req_full("172.17.0.1", method=method))
+
+    assert exc.value.status_code == 403
+
+
+def test_legacy_loopback_guard_allows_authenticated_server_mode_mutation(monkeypatch):
+    monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
+    monkeypatch.setenv("OMNIVOICE_API_KEY", "s3cret")
+
+    require_loopback(
+        _req_full(
+            "172.17.0.1",
+            method="POST",
+            headers={"authorization": "Bearer s3cret"},
+        )
+    )
+
+
+def test_server_mode_side_effectful_get_requires_api_key(monkeypatch):
+    monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
+    monkeypatch.delenv("OMNIVOICE_API_KEY", raising=False)
+
+    with pytest.raises(HTTPException) as exc:
+        require_admin_action(_req_full("172.17.0.1", method="GET"))
+
+    assert exc.value.status_code == 403
+
+
+def test_server_mode_side_effectful_get_accepts_api_key(monkeypatch):
+    monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
+    monkeypatch.setenv("OMNIVOICE_API_KEY", "s3cret")
+
+    require_admin_action(
+        _req_full(
+            "172.17.0.1",
+            method="GET",
+            headers={"authorization": "Bearer s3cret"},
+        )
+    )
+
+
+def test_side_effectful_get_rejects_remote_api_key_outside_server_mode(monkeypatch):
+    monkeypatch.delenv("OMNIVOICE_SERVER_MODE", raising=False)
+    monkeypatch.setenv("OMNIVOICE_API_KEY", "s3cret")
+
+    with pytest.raises(HTTPException) as exc:
+        require_admin_action(
+            _req_full(
+                "10.0.0.5",
+                method="GET",
+                headers={"authorization": "Bearer s3cret"},
+            )
+        )
+
+    assert exc.value.status_code == 403
+
+
+def test_side_effectful_get_rejects_pin_and_trusted_network(monkeypatch):
+    monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
+    monkeypatch.setenv("OMNIVOICE_TRUSTED_NETWORKS", "10.0.0.0/8")
+    monkeypatch.delenv("OMNIVOICE_API_KEY", raising=False)
+
+    with pytest.raises(HTTPException) as exc:
+        require_admin_action(
+            _req_full(
+                "10.1.2.3",
+                method="GET",
+                pin="123456",
+                headers={"x-omnivoice-pin": "123456"},
+            )
+        )
+
+    assert exc.value.status_code == 403
+
+
 # Server mode + trusted network + credential — issue #1213.
 # Regression for the two-tier collapse: with OMNIVOICE_SERVER_MODE=1 the
 # loopback origin is unenforceable, so admin can't require true loopback. But a
-# configured credential (API key / PIN) must still gate admin — a trusted-network
-# client that presents NO credential must NOT reach /system/* or /api/settings/*
-# just because is_local_host exempts it from the consumption middleware.
+# configured API key must still gate admin — a trusted-network client that
+# presents NO key must NOT reach /system/* or /api/settings/* just because
+# is_local_host exempts it from the consumption middleware.
 
 
 def test_server_mode_trusted_network_no_credential_reaches_admin(monkeypatch):
@@ -232,21 +325,36 @@ def test_server_mode_admin_rejects_wrong_api_key(monkeypatch):
     assert exc.value.status_code == 403
 
 
-def test_server_mode_pin_does_not_unlock_admin(monkeypatch):
+def test_server_mode_pin_only_keeps_admin_loopback_only(monkeypatch):
     # CodeRabbit #1213: the 6-digit share PIN is a CONSUMPTION credential and is
     # brute-forceable (10^6, no lockout), so it must NEVER gate the RCE-class
-    # admin surface. With a PIN set but no API key, admin is still *gated* (not
-    # left open) — but only loopback or the long API key can reach it. Presenting
-    # even the correct PIN over the network does NOT unlock admin.
+    # admin surface. Once a PIN is configured, bare read-only discovery closes;
+    # presenting that PIN still cannot authorize either a read or a write.
     monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
     monkeypatch.setenv("OMNIVOICE_TRUSTED_NETWORKS", "10.0.0.0/8")
     monkeypatch.delenv("OMNIVOICE_API_KEY", raising=False)
-    # No PIN presented → 403.
+    # No PIN presented → discovery denied.
     with pytest.raises(HTTPException):
         require_loopback(_req_full("10.1.2.3", pin="1234"))
-    # Correct PIN presented → STILL 403 (the PIN never gates admin).
+    # Correct PIN presented → STILL denied (the PIN never gates admin).
     with pytest.raises(HTTPException):
-        require_loopback(_req_full("10.1.2.3", pin="1234", headers={"x-omnivoice-pin": "1234"}))
+        require_loopback(
+            _req_full(
+                "10.1.2.3",
+                pin="1234",
+                headers={"x-omnivoice-pin": "1234"},
+            )
+        )
+    # Mutations are denied for the same reason.
+    with pytest.raises(HTTPException):
+        require_loopback(
+            _req_full(
+                "10.1.2.3",
+                pin="1234",
+                method="POST",
+                headers={"x-omnivoice-pin": "1234"},
+            )
+        )
     # Loopback admin still needs no credential (the local operator path)…
     require_loopback(_req_full("127.0.0.1", pin="1234"))
     # …and the trusted client keeps its consumption exemption.
@@ -261,9 +369,9 @@ def test_server_mode_loopback_admin_never_needs_credential(monkeypatch):
     require_loopback(_req_full("127.0.0.1"))  # must not raise
 
 
-# GHAS #506/#440/#441: require_loopback permits an unconfigured bare Docker
-# server for compatibility. RCE/filesystem-capable routers use the stricter,
-# method-aware admin gate instead.
+# GHAS #506/#440/#441: bare Docker retains read-only discovery for bootstrap.
+# RCE/filesystem-capable routers use the method-aware admin gate, while the
+# legacy loopback guard independently fails closed on accidental mutations.
 
 
 @pytest.mark.parametrize("method", ["POST", "PUT", "PATCH", "DELETE"])
@@ -281,10 +389,12 @@ def test_server_mode_admin_read_keeps_bare_docker_bootstrap(monkeypatch):
     require_admin(_req_full("172.17.0.1", method="GET"))
 
 
-def test_server_mode_admin_read_keeps_pin_only_discovery(monkeypatch):
+def test_server_mode_admin_read_rejects_pin_only_deployment(monkeypatch):
     monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
     monkeypatch.delenv("OMNIVOICE_API_KEY", raising=False)
-    require_admin(_req_full("172.17.0.1", method="GET", pin="123456"))
+    with pytest.raises(HTTPException) as exc:
+        require_admin(_req_full("172.17.0.1", method="GET", pin="123456"))
+    assert exc.value.status_code == 403
 
 
 def test_server_mode_admin_mutation_allows_api_key(monkeypatch):
@@ -297,6 +407,40 @@ def test_server_mode_admin_mutation_allows_api_key(monkeypatch):
     ))
 
 
+def test_whitespace_only_api_key_cannot_authorize_admin_mutation(monkeypatch):
+    monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
+    monkeypatch.setenv("OMNIVOICE_API_KEY", "   ")
+
+    for credential in (
+        {"query": {"api_key": "   "}},
+        {"cookies": {"ov_key": "   "}},
+    ):
+        with pytest.raises(HTTPException) as exc:
+            require_admin(
+                _req_full("172.17.0.1", method="POST", **credential)
+            )
+        assert exc.value.status_code == 403
+
+    monkeypatch.setenv("OMNIVOICE_API_KEY", "  s3cret  ")
+    require_admin(
+        _req_full("172.17.0.1", method="POST", query={"api_key": " s3cret "})
+    )
+
+
+def test_whitespace_query_does_not_shadow_admin_key_cookie(monkeypatch):
+    monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
+    monkeypatch.setenv("OMNIVOICE_API_KEY", "s3cret")
+
+    require_admin(
+        _req_full(
+            "172.17.0.1",
+            method="POST",
+            query={"api_key": "   "},
+            cookies={"ov_key": "s3cret"},
+        )
+    )
+
+
 def test_server_mode_desktop_capability_rejects_remote_api_key(monkeypatch):
     monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
     monkeypatch.setenv("OMNIVOICE_API_KEY", "s3cret")
diff --git a/tests/test_mcp_bindings.py b/tests/test_mcp_bindings.py
index 93935963..f28e408a 100644
--- a/tests/test_mcp_bindings.py
+++ b/tests/test_mcp_bindings.py
@@ -206,6 +206,20 @@ def test_rest_crud_roundtrip(client):
     assert client.delete("/api/mcp/bindings/claude-code").status_code == 404
 
 
+def test_server_mode_binding_mutations_require_api_key(client, monkeypatch):
+    from fastapi.testclient import TestClient
+
+    monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
+    monkeypatch.delenv("OMNIVOICE_API_KEY", raising=False)
+    remote = TestClient(client.app, client=("172.17.0.1", 50000))
+
+    assert remote.get("/api/mcp/bindings").status_code == 200
+    assert remote.put(
+        "/api/mcp/bindings", json={"client_id": "attacker"}
+    ).status_code == 403
+    assert remote.delete("/api/mcp/bindings/attacker").status_code == 403
+
+
 def test_rest_rejects_empty_client_id(client):
     r = client.put("/api/mcp/bindings", json={"client_id": ""})
     assert r.status_code == 422  # pydantic min_length
diff --git a/tests/test_media_tools.py b/tests/test_media_tools.py
index 94cd8f1e..0483b27f 100644
--- a/tests/test_media_tools.py
+++ b/tests/test_media_tools.py
@@ -432,7 +432,7 @@ def test_router_ytdlp_routes_not_shadowed_by_tool_param(mt, monkeypatch):
     assert r.json()["state"] == "running"
 
 
-def test_router_is_loopback_gated(mt):
+def test_router_is_admin_gated(mt):
     from main import app
     c = TestClient(app)  # client.host = 'testclient' → non-loopback
     for method, path in [
@@ -442,4 +442,21 @@ def test_router_is_loopback_gated(mt):
         ("post", "/media-tools/ytdlp/update"),
     ]:
         r = getattr(c, method)(path)
-        assert r.status_code == 403, f"{path} must be loopback-only"
+        assert r.status_code == 403, f"{path} must be admin-only"
+
+
+def test_server_mode_media_tool_mutations_require_api_key(mt, monkeypatch):
+    from main import app
+
+    monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
+    monkeypatch.delenv("OMNIVOICE_API_KEY", raising=False)
+    remote = TestClient(app, client=("172.17.0.1", 50000))
+
+    assert remote.get("/media-tools/status").status_code == 200
+    for path in (
+        "/media-tools/acquire",
+        "/media-tools/ytdlp/update",
+        "/media-tools/ytdlp/restore",
+        "/media-tools/ffmpeg/use-system",
+    ):
+        assert remote.post(path).status_code == 403, path
diff --git a/tests/test_pronunciation_api.py b/tests/test_pronunciation_api.py
index 416fa558..f7da1873 100644
--- a/tests/test_pronunciation_api.py
+++ b/tests/test_pronunciation_api.py
@@ -217,6 +217,22 @@ def test_crud_roundtrip(client):
     assert client.get("/pronunciation").json() == []
 
 
+def test_server_mode_pronunciation_mutations_require_api_key(client, monkeypatch):
+    from fastapi.testclient import TestClient
+
+    monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
+    monkeypatch.delenv("OMNIVOICE_API_KEY", raising=False)
+    remote = TestClient(client.app, client=("172.17.0.1", 50000))
+
+    assert remote.get("/pronunciation").status_code == 200
+    assert remote.post(
+        "/pronunciation", json={"term": "GIF", "replacement": "jiff"}
+    ).status_code == 403
+    assert remote.post(
+        "/pronunciation/import", json={"entries": [], "replace": True}
+    ).status_code == 403
+
+
 def test_create_rejects_blank_term(client):
     assert client.post("/pronunciation", json={"term": "   "}).status_code == 400
 
diff --git a/tests/test_router_smoke.py b/tests/test_router_smoke.py
index 84f2e238..083bf3f6 100644
--- a/tests/test_router_smoke.py
+++ b/tests/test_router_smoke.py
@@ -40,7 +40,7 @@ def client():
 
     # `client=("127.0.0.1", 50000)` so `request.client.host` resolves to a
     # loopback address — the system router is gated by a router-level
-    # `require_loopback` dependency. Smoke tests are happy-path tests and
+    # `require_admin` dependency. Smoke tests are happy-path tests and
     # should pass the gate.
     return TestClient(app, client=("127.0.0.1", 50000))
 
diff --git a/tests/test_worker_join_api.py b/tests/test_worker_join_api.py
index 0024ac45..732aa488 100644
--- a/tests/test_worker_join_api.py
+++ b/tests/test_worker_join_api.py
@@ -24,14 +24,14 @@ import pytest
 from fastapi import FastAPI
 from fastapi.testclient import TestClient
 
-from api.dependencies import require_loopback
+from api.dependencies import require_admin
 from api.routers import workers as workers_router
 from worker import agent as worker_agent
 
 
 @pytest.fixture
 def client(monkeypatch, tmp_path):
-    """The workers router with the loopback guard stubbed out."""
+    """The workers router with the admin guard stubbed out."""
     settings: dict[str, str] = {}
 
     class _Store:
@@ -59,7 +59,7 @@ def client(monkeypatch, tmp_path):
 
     app = FastAPI()
     app.include_router(workers_router.router)
-    app.dependency_overrides[require_loopback] = lambda: None
+    app.dependency_overrides[require_admin] = lambda: None
     with TestClient(app) as c:
         yield c, settings
 
diff --git a/tests/test_worker_service_api.py b/tests/test_worker_service_api.py
index cd5ab744..fedd2c8a 100644
--- a/tests/test_worker_service_api.py
+++ b/tests/test_worker_service_api.py
@@ -214,17 +214,17 @@ def _app():
 
 @pytest.fixture
 def client(db):
-    """A client that satisfies the loopback gate.
+    """A client that satisfies the admin gate.
 
     The gate is real and is exercised separately below; overriding it here
     keeps every other test about the endpoint's own behaviour.
     """
     from fastapi.testclient import TestClient
 
-    from api.dependencies import require_loopback
+    from api.dependencies import require_admin
 
     app = _app()
-    app.dependency_overrides[require_loopback] = lambda: None
+    app.dependency_overrides[require_admin] = lambda: None
     return TestClient(app)
 
 
@@ -239,6 +239,20 @@ def test_management_endpoints_are_loopback_only(db):
     assert unguarded.delete("/workers/anything").status_code == 403
 
 
+def test_server_mode_worker_mutations_require_api_key(db, monkeypatch):
+    """Bare Docker discovery stays usable; its worker controls stay closed."""
+    from fastapi.testclient import TestClient
+
+    monkeypatch.setenv("OMNIVOICE_SERVER_MODE", "1")
+    monkeypatch.delenv("OMNIVOICE_API_KEY", raising=False)
+    remote = TestClient(_app(), client=("172.17.0.1", 50000))
+
+    assert remote.get("/workers").status_code == 200
+    assert remote.post("/workers/enabled", json={"enabled": True}).status_code == 403
+    assert remote.post("/workers/agent/join", json={"token": "hostile"}).status_code == 403
+    assert remote.delete("/workers/anything").status_code == 403
+
+
 def test_listing_workers_is_safe_when_the_feature_is_off(client):
     response = client.get("/workers")
     assert response.status_code == 200