diff --git a/agent/auxiliary_client.py b/agent/auxiliary_client.py
index 1bf3385931..944e3ac6ef 100644
--- a/agent/auxiliary_client.py
+++ b/agent/auxiliary_client.py
@@ -1048,7 +1048,7 @@ def _nous_min_key_ttl_seconds() -> int:
 
 
 def _scoped_key_env(name: str) -> str:
-    """Read a provider API key env var through the profile secret scope.
+    """Read a provider API key (or its paired base-URL) env var through the profile secret scope.
 
     In agent turns the scope's verdict is authoritative (a scoped miss must not borrow another
     profile's key); unscoped startup/CLI paths fall back to os.environ.
@@ -1971,8 +1971,8 @@ def _resolve_xai_oauth_for_aux() -> Optional[Tuple[str, str]]:
                 ).strip()
                 _url = lambda v: str(v or "").strip().rstrip("/")  # noqa: E731
                 base_url = _xai_validate_inference_base_url(
-                    _url(os.getenv("HERMES_XAI_BASE_URL", ""))
-                    or _url(os.getenv("XAI_BASE_URL", ""))
+                    _url(_scoped_key_env("HERMES_XAI_BASE_URL"))
+                    or _url(_scoped_key_env("XAI_BASE_URL"))
                     or _url(getattr(entry, "runtime_base_url", None))
                     or _url(getattr(entry, "base_url", None)),
                     fallback=DEFAULT_XAI_OAUTH_BASE_URL,
@@ -2246,7 +2246,7 @@ def _try_nous(vision: bool = False) -> Tuple[Optional[OpenAI], Optional[str]]:
             _mark_provider_unhealthy("nous", ttl=60)
             return None, None
         base_url = str(
-            (nous or {}).get("inference_base_url") or os.getenv("NOUS_INFERENCE_BASE_URL", _NOUS_DEFAULT_BASE_URL)
+            (nous or {}).get("inference_base_url") or _scoped_key_env("NOUS_INFERENCE_BASE_URL") or _NOUS_DEFAULT_BASE_URL
         ).rstrip("/")
     lane = "vision" if vision else "text"
     # The free tier's host serves exactly one model, for every lane: asking it for the Portal's
@@ -2632,7 +2632,8 @@ def _resolve_custom_runtime() -> Tuple[Optional[str], Optional[str], Optional[st
         logger.debug("Auxiliary client: custom runtime resolution failed: %s", exc)
         runtime = None
     if not isinstance(runtime, dict):
-        openai_base = os.getenv("OPENAI_BASE_URL", "").strip().rstrip("/")
+        # Base URL is per-profile like the key one line below (a scoped key must not hit the default's proxy).
+        openai_base = _scoped_key_env("OPENAI_BASE_URL").rstrip("/")
         if not openai_base:
             return None, None, None
         runtime = {"base_url": openai_base, "api_key": _scoped_key_env("OPENAI_API_KEY")}
@@ -5605,7 +5606,7 @@ def _expand_direct_api_alias(prov: Optional[str], existing_base: Optional[str])
         from hermes_cli.runtime_provider import _get_named_custom_provider
         if _get_named_custom_provider(prov) is not None:
             return prov, existing_base
-    return "custom", existing_base or os.getenv("OPENAI_BASE_URL", "").strip().rstrip("/") or target_base
+    return "custom", existing_base or _scoped_key_env("OPENAI_BASE_URL").rstrip("/") or target_base
 
 
 def _preserve_provider_with_base_url(prov: Optional[str]) -> bool:
diff --git a/agent/i18n.py b/agent/i18n.py
index 02f0c97036..03a549c8c3 100644
--- a/agent/i18n.py
+++ b/agent/i18n.py
@@ -118,9 +118,11 @@ def _flatten_into(node: Any, prefix: str, out: dict[str, str]) -> None:
         out[prefix] = node
 
 
-@lru_cache(maxsize=1)
-def _config_language_cached() -> str | None:
-    """``display.language`` from config.yaml, read once per process (``t()`` is a hot path)."""
+@lru_cache(maxsize=8)
+def _config_language_cached(hermes_home: str) -> str | None:
+    """``display.language`` from config.yaml, read once per profile home (``t()`` is a hot path).
+    Keyed by home so a multiplexed gateway serving several profiles doesn't freeze the first
+    profile's language for every other profile."""
     try:
         from hermes_cli.config import load_config_readonly
         lang = (load_config_readonly().get("display") or {}).get("language")
@@ -130,6 +132,11 @@ def _config_language_cached() -> str | None:
         return None
 
 
+def _config_language() -> str | None:
+    from hermes_constants import get_hermes_home
+    return _config_language_cached(str(get_hermes_home()))
+
+
 def reset_language_cache() -> None:
     """Invalidate cached language resolution and catalogs (call after ``save_config`` changes ``display.language``)."""
     _config_language_cached.cache_clear()
@@ -138,9 +145,15 @@ def reset_language_cache() -> None:
 
 
 def get_language() -> str:
-    """Resolve the active language using env > config > default order."""
-    env_lang = os.environ.get("HERMES_LANGUAGE")
-    return _normalize_lang(env_lang) if env_lang else _config_language_cached() or DEFAULT_LANGUAGE
+    """Resolve the active language using env > config > default order. ``HERMES_LANGUAGE`` is a
+    per-profile ``.env`` value, so it is read through the secret scope: under multiplexing a raw
+    environ read would impose the default profile's language on every other profile."""
+    from agent.secret_scope import UnscopedSecretError, get_secret
+    try:
+        env_lang = get_secret("HERMES_LANGUAGE")
+    except UnscopedSecretError:
+        env_lang = os.environ.get("HERMES_LANGUAGE")  # unscoped default-profile path: environ IS its own value
+    return _normalize_lang(env_lang) if env_lang else _config_language() or DEFAULT_LANGUAGE
 
 
 def t(key: str, lang: str | None = None, **format_kwargs: Any) -> str:
diff --git a/agent/inline_tool_executors.py b/agent/inline_tool_executors.py
index e1d5d1ad67..98b9ef85ea 100644
--- a/agent/inline_tool_executors.py
+++ b/agent/inline_tool_executors.py
@@ -104,7 +104,8 @@ def _session_search(agent, args: dict, ctx: InlineToolContext) -> Any:
         (
             ("query", "query", ""), ("role_filter", "role_filter"), ("limit", "limit", 3),
             ("session_id", "session_id"), ("around_message_id", "around_message_id"),
-            ("window", "window", 5), ("sort", "sort"), ("detail", "detail", "adaptive"),
+            ("window", "window", 5), ("sort", "sort"), ("profile", "profile"),
+            ("detail", "detail", "adaptive"),
         ),
         db=session_db, current_session_id=agent.session_id,
     )
diff --git a/agent/outbound_webhooks.py b/agent/outbound_webhooks.py
index 2a637bae24..a7df914645 100644
--- a/agent/outbound_webhooks.py
+++ b/agent/outbound_webhooks.py
@@ -14,7 +14,6 @@ import hashlib
 import hmac
 import json
 import logging
-import os
 import queue
 import re
 import threading
@@ -201,10 +200,14 @@ def _parse_single_target(index: int, raw: Any) -> Optional[WebhookTarget]:
         warn(".timeout must be an int (got %r); using default %ds", timeout_raw, DEFAULT_TIMEOUT_SECONDS)
         timeout = DEFAULT_TIMEOUT_SECONDS
     name = raw.get("name")
-    # ``secret_env`` (env var name, preferred) wins over inline ``secret``.
+    # ``secret_env`` (env var name, preferred) wins over inline ``secret``. Read through the profile
+    # secret scope: the gateway registers each multiplexed profile's targets inside that profile's
+    # scope, and a raw environ read would sign a secondary's deliveries with the DEFAULT profile's
+    # secret (or leave them unsigned when the var lives only in the secondary's .env).
     secret_env = raw.get("secret_env")
     if isinstance(secret_env, str) and secret_env.strip():
-        secret = os.environ.get(secret_env.strip(), "") or None
+        from agent.secret_scope import get_secret
+        secret = get_secret(secret_env.strip(), "") or None
         if secret is None:
             warn(".secret_env=%r is not set in the environment — deliveries will be UNSIGNED", secret_env.strip())
     else:
diff --git a/gateway/run_agent_cache.py b/gateway/run_agent_cache.py
index 71814d7c9e..85df54235b 100644
--- a/gateway/run_agent_cache.py
+++ b/gateway/run_agent_cache.py
@@ -597,18 +597,45 @@ class GatewayAgentCacheMixin:
             return
         self._spawn_release_thread(
             self._release_evicted_agent_soft, (agent,), f"agent-evict-{str(session_key)[:24]}", inline_fallback=True,
+            session_key=session_key,
         )
 
-    def _spawn_release_thread(self, target, args: tuple, name: str, *, inline_fallback: bool) -> None:
+    def _spawn_release_thread(self, target, args: tuple, name: str, *, inline_fallback: bool,
+                              session_key: Optional[str] = None) -> None:
         """Run a release on a daemon thread. ``inline_fallback`` runs it inline (best-effort) when no
-        thread can start (interpreter shutdown); otherwise a spawn failure propagates, as on main."""
+        thread can start (interpreter shutdown); otherwise a spawn failure propagates, as on main.
+        The thread runs inside the owning profile's scope (see ``_run_release_in_profile_scope``)."""
+        import contextvars
+        ctx = contextvars.copy_context()
         try:
-            threading.Thread(target=target, args=args, daemon=True, name=name).start()
+            threading.Thread(target=ctx.run, args=(self._run_release_in_profile_scope, target, args, session_key),
+                             daemon=True, name=name).start()
         except Exception:
             if not inline_fallback:
                 raise
             with suppress(Exception):
-                target(*args)
+                ctx.run(self._run_release_in_profile_scope, target, args, session_key)
+
+    def _run_release_in_profile_scope(self, target, args: tuple, session_key: Optional[str]) -> None:
+        """Call ``target(*args)`` under the profile that owns ``session_key``. Threads start with an
+        EMPTY context, so a bare thread would commit end-of-session memory (provider ``on_session_end``
+        reads credentials/home at call time) under the LAUNCH profile — lost memories or a secondary's
+        transcript extracted into the default profile's provider namespace. In-turn callers already
+        carry the scope (``copy_context`` preserves it); the unscoped housekeeping sweep resolves the
+        owner from the session key (``agent:<profile>:...``) and enters that profile's scope."""
+        from agent.secret_scope import current_secret_scope, is_multiplex_active
+        if current_secret_scope() is not None or not is_multiplex_active():
+            target(*args)
+            return
+        from gateway.run import _profile_runtime_scope
+        from hermes_constants import get_hermes_home
+        home = None
+        store = getattr(self, "session_store", None)
+        if session_key and store is not None:
+            with suppress(Exception):
+                home = store._profile_home_for_key(session_key)
+        with _profile_runtime_scope(home or get_hermes_home()):
+            target(*args)
 
     def _commit_memory_before_soft_evict(self, agent: Any, key: str) -> None:
         """Commit the live transcript to memory providers before resource-only eviction."""
@@ -763,7 +790,8 @@ class GatewayAgentCacheMixin:
         while plan:
             key, agent = plan.pop(0)  # FIFO — evict LRU-first order preserved
             try:
-                self._commit_then_release_soft(agent, key)
+                # Pressure sweeps run from the unscoped housekeeping watcher: enter each owner's scope.
+                self._run_release_in_profile_scope(self._commit_then_release_soft, (agent, key), key)
             except Exception as _e:
                 logger.debug("Pressure release failed for %s: %s", key, _e)
             del agent
@@ -803,7 +831,8 @@ class GatewayAgentCacheMixin:
             if agent is not None:
                 # Commit end-of-session memory, then soft-release, both on the daemon thread so the
                 # (possibly network-bound) provider call never blocks the held cache lock.
-                self._spawn_release_thread(self._commit_then_release_soft, (agent, key), f"agent-cache-evict-{key[:24]}", inline_fallback=False)
+                self._spawn_release_thread(self._commit_then_release_soft, (agent, key), f"agent-cache-evict-{key[:24]}",
+                                           inline_fallback=False, session_key=key)
 
     def _sweep_idle_cached_agents(self) -> int:
         """Evict cached agents idle past the idle TTL (lock acquired internally; cleanup on daemon
@@ -829,5 +858,6 @@ class GatewayAgentCacheMixin:
                 _cache.pop(key, None)
         for key, agent in to_evict:
             logger.info("Agent cache idle-TTL evict: session=%s (idle=%.0fs)", key, now - getattr(agent, "_last_activity_ts", now))
-            self._spawn_release_thread(self._commit_then_release_soft, (agent, key), f"agent-cache-idle-{key[:24]}", inline_fallback=False)
+            self._spawn_release_thread(self._commit_then_release_soft, (agent, key), f"agent-cache-idle-{key[:24]}",
+                                       inline_fallback=False, session_key=key)
         return len(to_evict)
diff --git a/gateway/run_turn.py b/gateway/run_turn.py
index 472b008a7c..8b3b0a4dec 100644
--- a/gateway/run_turn.py
+++ b/gateway/run_turn.py
@@ -2352,9 +2352,16 @@ class GatewayTurnMixin:
             return t("gateway.reload_mcp.failed", error=e)
 
     def _get_proxy_url(self) -> Optional[str]:
-        """Proxy URL if proxy mode is configured (GATEWAY_PROXY_URL env wins over ``gateway.proxy_url``)."""
+        """Proxy URL if proxy mode is configured (GATEWAY_PROXY_URL env wins over ``gateway.proxy_url``).
+        Per-profile like GATEWAY_PROXY_KEY: under multiplex a raw environ read would ship a secondary's
+        turns (authenticated with ITS scoped key) to the default profile's proxy. Same fallback shape as
+        the key — only ``UnscopedSecretError`` (the unscoped default-profile path) reads the env."""
         from gateway.run import _load_gateway_config
-        url = os.getenv("GATEWAY_PROXY_URL", "").strip()
+        from agent.secret_scope import UnscopedSecretError, get_secret
+        try:
+            url = (get_secret("GATEWAY_PROXY_URL") or "").strip()
+        except UnscopedSecretError:
+            url = os.getenv("GATEWAY_PROXY_URL", "").strip()
         if not url:
             url = ((_load_gateway_config().get("gateway") or {}).get("proxy_url") or "").strip()
         return url.rstrip("/") if url else None
diff --git a/hermes_cli/auth_nous.py b/hermes_cli/auth_nous.py
index 97057274f3..59873e998f 100644
--- a/hermes_cli/auth_nous.py
+++ b/hermes_cli/auth_nous.py
@@ -139,10 +139,17 @@ def _nous_inference_env_override() -> Optional[str]:
     """User-set ``NOUS_INFERENCE_BASE_URL`` override (trailing slash stripped) or None.
 
     Documented dev/staging escape hatch; the env source is trusted, so unlike Portal-returned URLs
-    it is intentionally NOT gated by the network host allowlist.
+    it is intentionally NOT gated by the network host allowlist. Read through the profile-aware
+    resolver so a multiplexed profile uses its own override and never inherits the default
+    profile's process-wide value (#65941).
     """
     from hermes_cli.auth import _optional_base_url
-    return _optional_base_url(os.getenv("NOUS_INFERENCE_BASE_URL"))
+    from agent.secret_scope import UnscopedSecretError, get_secret
+    try:
+        override = get_secret("NOUS_INFERENCE_BASE_URL")
+    except UnscopedSecretError:
+        override = os.getenv("NOUS_INFERENCE_BASE_URL")  # unscoped default-profile/CLI path: environ IS its own value
+    return _optional_base_url(override)
 
 
 def _nous_portal_env_override() -> Optional[str]:
diff --git a/plugins/browser/browserbase/provider.py b/plugins/browser/browserbase/provider.py
index 9c1dc982db..2a9c51e28f 100644
--- a/plugins/browser/browserbase/provider.py
+++ b/plugins/browser/browserbase/provider.py
@@ -48,7 +48,8 @@ class BrowserbaseBrowserProvider(CloudBrowserProvider):
         return {
             "api_key": api_key,
             "project_id": project_id,
-            "base_url": os.environ.get("BROWSERBASE_BASE_URL", "https://api.browserbase.com").rstrip("/"),
+            # Per-profile like the key: the scoped key must not be sent to the default profile's endpoint.
+            "base_url": (get_secret("BROWSERBASE_BASE_URL", "") or "https://api.browserbase.com").rstrip("/"),
         }
 
     def _headers(self, config: Dict[str, Any]) -> Dict[str, str]:
diff --git a/plugins/browser/firecrawl/provider.py b/plugins/browser/firecrawl/provider.py
index d8f1ee4398..e2b17d9256 100644
--- a/plugins/browser/firecrawl/provider.py
+++ b/plugins/browser/firecrawl/provider.py
@@ -31,7 +31,8 @@ class FirecrawlBrowserProvider(CloudBrowserProvider):
     ]
 
     def _api_url(self) -> str:
-        return os.environ.get("FIRECRAWL_API_URL", _BASE_URL)
+        # Per-profile like the key: the scoped key must not be sent to the default profile's endpoint.
+        return get_secret("FIRECRAWL_API_URL", "") or _BASE_URL
 
     def _get_config_or_none(self) -> Optional[Dict[str, Any]]:
         return {"base_url": self._api_url()} if get_secret("FIRECRAWL_API_KEY") else None
diff --git a/plugins/memory/hindsight/__init__.py b/plugins/memory/hindsight/__init__.py
index a035edd13b..381b43c657 100644
--- a/plugins/memory/hindsight/__init__.py
+++ b/plugins/memory/hindsight/__init__.py
@@ -241,17 +241,20 @@ def _load_config() -> dict:
         if path.exists():
             with contextlib.suppress(Exception):
                 return json.loads(path.read_text(encoding="utf-8"))
+    # Mode, bank (the data partition), endpoint and retain shaping are per-profile .env values like
+    # the key beside them: read through the secret scope so a multiplexed secondary never inherits
+    # the default profile's bank/mode. Tuning knobs (timeouts, budget) stay process-global.
     return {
-        "mode": os.environ.get("HINDSIGHT_MODE", "cloud"),
+        "mode": get_secret("HINDSIGHT_MODE", "") or "cloud",
         "apiKey": get_secret("HINDSIGHT_API_KEY", ""),
         "timeout": _parse_int_setting(os.environ.get("HINDSIGHT_TIMEOUT"), _DEFAULT_TIMEOUT),
         "idle_timeout": _parse_int_setting(os.environ.get("HINDSIGHT_IDLE_TIMEOUT"), _DEFAULT_IDLE_TIMEOUT),
-        "retain_tags": os.environ.get("HINDSIGHT_RETAIN_TAGS", ""),
-        "observation_scopes": os.environ.get("HINDSIGHT_RETAIN_OBSERVATION_SCOPES", ""),
+        "retain_tags": get_secret("HINDSIGHT_RETAIN_TAGS", "") or "",
+        "observation_scopes": get_secret("HINDSIGHT_RETAIN_OBSERVATION_SCOPES", "") or "",
         "retain_source": os.environ.get("HINDSIGHT_RETAIN_SOURCE", _DEFAULT_RETAIN_SOURCE),
         "retain_user_prefix": os.environ.get("HINDSIGHT_RETAIN_USER_PREFIX", "User"),
         "retain_assistant_prefix": os.environ.get("HINDSIGHT_RETAIN_ASSISTANT_PREFIX", "Assistant"),
-        "banks": {"hermes": {"bankId": os.environ.get("HINDSIGHT_BANK_ID", "hermes"),
+        "banks": {"hermes": {"bankId": get_secret("HINDSIGHT_BANK_ID", "") or "hermes",
                              "budget": os.environ.get("HINDSIGHT_BUDGET", "mid"), "enabled": True}},
     }
 
@@ -357,7 +360,7 @@ class HindsightMemoryProvider(MemoryProvider):
             if mode in _LOCAL_MODES:
                 return _check_local_runtime()[0]
             return mode == "local_external" or bool(
-                _cloud_api_key(cfg) or cfg.get("api_url") or os.environ.get("HINDSIGHT_API_URL", ""))
+                _cloud_api_key(cfg) or cfg.get("api_url") or get_secret("HINDSIGHT_API_URL", ""))
         except Exception:
             return False
 
@@ -708,7 +711,7 @@ class HindsightMemoryProvider(MemoryProvider):
         """Endpoint, bank and mode selectors from *cfg* (env fallbacks where documented)."""
         self._api_key = _cloud_api_key(cfg)
         default_url = _DEFAULT_LOCAL_URL if self._mode in {"local_embedded", "local_external"} else _DEFAULT_API_URL
-        self._api_url = cfg.get("api_url") or os.environ.get("HINDSIGHT_API_URL", default_url)
+        self._api_url = cfg.get("api_url") or get_secret("HINDSIGHT_API_URL", "") or default_url
         self._llm_base_url = cfg.get("llm_base_url", "")
 
         banks = cfg_get(cfg, "banks", "hermes", default={})
diff --git a/plugins/memory/hindsight/embedded.py b/plugins/memory/hindsight/embedded.py
index 1a4ffa433a..27bf2de2e9 100644
--- a/plugins/memory/hindsight/embedded.py
+++ b/plugins/memory/hindsight/embedded.py
@@ -170,7 +170,14 @@ def _build_embedded_profile_env(config: dict[str, Any], *, llm_api_key: str | No
         "HINDSIGHT_API_LLM_MODEL": str(config.get("llm_model", "")),
         "HINDSIGHT_API_LOG_LEVEL": "info",
     }
-    base_url = config.get("llm_base_url") or os.environ.get("HINDSIGHT_API_LLM_BASE_URL", "")
+    # Base URL is per-profile like the key beside it (the scoped key must not go to the default's host);
+    # on the scopeless daemon worker a miss is a miss, never os.environ (same rule as the key above).
+    base_url = config.get("llm_base_url")
+    if not base_url:
+        try:
+            base_url = get_secret("HINDSIGHT_API_LLM_BASE_URL", "") or ""
+        except UnscopedSecretError:
+            base_url = ""
     if base_url:
         env_values["HINDSIGHT_API_LLM_BASE_URL"] = str(base_url)
     if (idle_timeout := config.get("idle_timeout")) is None:
diff --git a/plugins/memory/honcho/client.py b/plugins/memory/honcho/client.py
index e600bb651a..035173688a 100644
--- a/plugins/memory/honcho/client.py
+++ b/plugins/memory/honcho/client.py
@@ -67,9 +67,11 @@ def _host_block(raw: dict, host: str) -> dict:
 
 
 def resolve_active_host() -> str:
-    """Honcho host key: HERMES_HONCHO_HOST env, else the active profile. The config's
-    ``defaultHost`` is honored only for the default profile so named profiles stay isolated."""
-    explicit = os.environ.get("HERMES_HONCHO_HOST", "").strip()
+    """Honcho host key: HERMES_HONCHO_HOST (profile-scoped .env), else the active profile. The config's
+    ``defaultHost`` is honored only for the default profile so named profiles stay isolated — which is
+    also why the override is read through the secret scope: from raw environ it would fold every
+    multiplexed profile onto the default profile's host block and peer."""
+    explicit = (get_secret("HERMES_HONCHO_HOST", "") or "").strip()
     if explicit:
         return explicit
     try:
@@ -249,8 +251,10 @@ def _is_local_base_url(base_url: str | None) -> bool:
 
 
 def _env_base_url() -> str | None:
-    """HONCHO_BASE_URL / HONCHO_URL (the SDK's own var); a deployment setting, so plain os.environ."""
-    return os.environ.get("HONCHO_BASE_URL", "").strip() or os.environ.get("HONCHO_URL", "").strip() or None
+    """HONCHO_BASE_URL / HONCHO_URL (the SDK's own var). A self-hosted URL varies per profile, so it is
+    read through the secret scope: the scoped HONCHO_API_KEY beside it must not be sent to the default
+    profile's server."""
+    return (get_secret("HONCHO_BASE_URL", "") or "").strip() or (get_secret("HONCHO_URL", "") or "").strip() or None
 
 
 def _connection_fields(look: _HostLookup, host: str, path: Path) -> dict[str, Any]:
@@ -412,7 +416,7 @@ class HonchoClientConfig:
         base_url = _sanitize_url(_env_base_url())
         return cls(
             host=resolved_host, workspace_id=workspace_id, api_key=api_key, base_url=base_url,
-            environment=os.environ.get("HONCHO_ENVIRONMENT", "production"),
+            environment=get_secret("HONCHO_ENVIRONMENT", "") or "production",
             timeout=_resolve_optional_float(os.environ.get("HONCHO_TIMEOUT")),
             ai_peer=resolved_host, enabled=bool(api_key or base_url),
             config_path=resolve_config_path(), hermes_home=get_hermes_home(),
diff --git a/plugins/memory/mem0/__init__.py b/plugins/memory/mem0/__init__.py
index acbaadd388..8d41f71f40 100644
--- a/plugins/memory/mem0/__init__.py
+++ b/plugins/memory/mem0/__init__.py
@@ -19,7 +19,7 @@ from pathlib import Path
 from typing import Any, Dict, List
 
 from agent.memory_provider import MemoryProvider
-from agent.secret_scope import get_secret
+from agent.secret_scope import UnscopedSecretError, get_secret
 from tools.registry import tool_error
 
 logger = logging.getLogger(__name__)
@@ -73,6 +73,15 @@ def _read_mem0_json(config_path: Path) -> dict:
     return {}
 
 
+def _scoped_env(name: str) -> str:
+    """Profile-scoped read of a non-secret mem0 setting; no scope under multiplex = unset (never
+    ``os.environ``). Only the API key may fail closed — OSS mode has none to read (#99121)."""
+    try:
+        return get_secret(name, "") or ""
+    except UnscopedSecretError:
+        return ""
+
+
 def _load_config() -> dict:
     """Env vars provide defaults; $HERMES_HOME/mem0.json overrides individual keys.
     Layering avoids a silent failure when the JSON file exists but lacks fields
@@ -80,9 +89,9 @@ def _load_config() -> dict:
     from hermes_constants import get_hermes_home
     # Identity (user/agent id), host and mode are .env values like the key: read them through the
     # profile scope too, or a secondary profile's memories land in the default profile's account.
-    config = {"mode": get_secret("MEM0_MODE", "") or "platform", "host": get_secret("MEM0_HOST", "") or "",
-              "agent_id": get_secret("MEM0_AGENT_ID", "") or "hermes", "oss": {}}
-    if user_id := get_secret("MEM0_USER_ID", ""):  # only when explicitly configured, so initialize() can fall back to the gateway-native id
+    config = {"mode": _scoped_env("MEM0_MODE") or "platform", "host": _scoped_env("MEM0_HOST"),
+              "agent_id": _scoped_env("MEM0_AGENT_ID") or "hermes", "oss": {}}
+    if user_id := _scoped_env("MEM0_USER_ID"):  # only when explicitly configured, so initialize() can fall back to the gateway-native id
         config["user_id"] = user_id
     file_cfg = _read_mem0_json(get_hermes_home() / "mem0.json")
     config.update({k: v for k, v in file_cfg.items() if v is not None and v != ""})
diff --git a/plugins/memory/mem0/_openai_llm.py b/plugins/memory/mem0/_openai_llm.py
index a5e19ee446..bf58c1a4c5 100644
--- a/plugins/memory/mem0/_openai_llm.py
+++ b/plugins/memory/mem0/_openai_llm.py
@@ -3,7 +3,6 @@
 from __future__ import annotations
 
 import logging
-import os
 from typing import Dict, List, Optional, Union
 
 from mem0.configs.llms.base import BaseLlmConfig
@@ -37,11 +36,15 @@ class DirectOpenAILLM(OpenAILLM):
         # Bypass OpenAILLM.__init__ (it picks OpenRouter when OPENROUTER_API_KEY is
         # set); LLMBase still owns validation and supported-parameter filtering.
         LLMBase.__init__(self, config)
-        api_key = self.config.api_key or os.getenv("OPENAI_API_KEY")
+        # OPENAI_API_KEY / OPENAI_BASE_URL are profile credentials: read them through the secret
+        # scope, never raw os.environ, or a multiplexed secondary's memory extraction runs on the
+        # default profile's OpenAI account (and its proxy).
+        from agent.secret_scope import get_secret
+        api_key = self.config.api_key or get_secret("OPENAI_API_KEY", "")
         if not api_key:
             raise ValueError("OpenAI API key is required for the Hermes Mem0 OSS provider")
         from openai import OpenAI
-        self.client = OpenAI(api_key=api_key, base_url=self.config.openai_base_url or os.getenv("OPENAI_BASE_URL") or "https://api.openai.com/v1")
+        self.client = OpenAI(api_key=api_key, base_url=self.config.openai_base_url or get_secret("OPENAI_BASE_URL", "") or "https://api.openai.com/v1")
 
     def generate_response(self, messages: List[Dict[str, str]], response_format=None, tools: Optional[List[Dict]] = None, tool_choice: str = "auto", **kwargs):
         params = self._get_supported_params(messages=messages, **kwargs)
diff --git a/plugins/memory/openviking/__init__.py b/plugins/memory/openviking/__init__.py
index 3bce35bf37..f5a9ee7f22 100644
--- a/plugins/memory/openviking/__init__.py
+++ b/plugins/memory/openviking/__init__.py
@@ -36,6 +36,7 @@ from urllib.request import url2pathname
 
 from agent.message_content import flatten_message_text
 from agent.memory_provider import MemoryProvider
+from agent.secret_scope import get_secret
 from agent.skill_commands import extract_user_instruction_from_skill_message
 from hermes_cli import __version__ as _HERMES_VERSION
 from tools.registry import tool_error
@@ -237,9 +238,11 @@ class _VikingClient:
         self._api_key = api_key
         # Account/user are local/trusted-mode tenant identity. API-key requests
         # omit these headers unless OpenViking explicitly asks for them (retry).
-        self._account = account or os.environ.get("OPENVIKING_ACCOUNT", "default")
-        self._user = user or os.environ.get("OPENVIKING_USER", "default")
-        self._agent = agent if agent is not None else os.environ.get("OPENVIKING_AGENT", _DEFAULT_AGENT)
+        # Tenant identity is a profile .env value: scope-read so a multiplexed
+        # secondary never writes into the default profile's tenant.
+        self._account = account or get_secret("OPENVIKING_ACCOUNT", "") or "default"
+        self._user = user or get_secret("OPENVIKING_USER", "") or "default"
+        self._agent = agent if agent is not None else (get_secret("OPENVIKING_AGENT", "") or _DEFAULT_AGENT)
         self._httpx = _get_httpx()
         if self._httpx is None:
             raise ImportError("httpx is required for OpenViking: pip install httpx")
@@ -759,19 +762,21 @@ def _ovcli_values_for(provider_config: dict) -> dict:
 def _resolve_connection_settings(provider_config: Optional[dict] = None) -> dict:
     """Layering: env -> linked ovcli profile -> config.yaml -> built-in default.
     An env account/user (even empty) is authoritative; the secret api_key never
-    comes from config.yaml."""
+    comes from config.yaml. Every env read goes through the profile secret scope:
+    under multiplexing ``os.environ`` is the DEFAULT profile's .env, and a raw read
+    would spend its key and tenant on behalf of a secondary profile."""
     provider_config = dict(provider_config or {})
     ovcli_values = _ovcli_values_for(provider_config)
 
     def layered(key: str, default: str = "", *, env_authoritative: bool = False) -> str:
-        env = os.environ.get(f"OPENVIKING_{key.upper()}")
+        env = get_secret(f"OPENVIKING_{key.upper()}")
         if env is not None:
             env = env.strip()
             if env_authoritative:
                 return env
         return env or ovcli_values.get(key) or _clean_config_value(provider_config.get(key)) or default
 
-    api_key_env = os.environ.get("OPENVIKING_API_KEY")
+    api_key_env = get_secret("OPENVIKING_API_KEY")
     return {
         "endpoint": _normalize_openviking_url(layered("endpoint", _DEFAULT_ENDPOINT)),
         "api_key": api_key_env.strip() if api_key_env is not None else ovcli_values.get("api_key", ""),
@@ -1254,7 +1259,7 @@ class OpenVikingMemoryProvider(MemoryProvider):
 
     def is_available(self) -> bool:
         """Configured? (env endpoint, config.yaml endpoint, or a linked ovcli profile). No network."""
-        if os.environ.get("OPENVIKING_ENDPOINT"):
+        if get_secret("OPENVIKING_ENDPOINT", ""):
             return True
         provider_config = _load_hermes_openviking_config()
         if _clean_config_value(provider_config.get("endpoint")):
diff --git a/plugins/memory/retaindb/__init__.py b/plugins/memory/retaindb/__init__.py
index 95ed0ded36..1e421b3659 100644
--- a/plugins/memory/retaindb/__init__.py
+++ b/plugins/memory/retaindb/__init__.py
@@ -327,11 +327,13 @@ class RetainDBMemoryProvider(MemoryProvider):
         ]
 
     def initialize(self, session_id: str, **kwargs) -> None:
-        # Non-secret fields resolve env -> config.yaml (written by the Dashboard) -> default.
+        # Non-secret fields resolve env (profile-scoped) -> config.yaml (written by the Dashboard) -> default.
         cfg = {k: v.strip() for k, v in _load_retaindb_config().items() if isinstance(v, str)}
-        base_url = re.sub(r"/+$", "", os.environ.get("RETAINDB_BASE_URL") or cfg.get("base_url") or _DEFAULT_BASE_URL)
+        base_url = re.sub(r"/+$", "", get_secret("RETAINDB_BASE_URL", "") or cfg.get("base_url") or _DEFAULT_BASE_URL)
         # Project: RETAINDB_PROJECT > config.yaml > hermes-<profile> > "default" (API auto-creates "default").
-        project = os.environ.get("RETAINDB_PROJECT") or cfg.get("project")
+        # The project is the data partition: read through the secret scope so a multiplexed secondary's
+        # memories never land in the default profile's project.
+        project = get_secret("RETAINDB_PROJECT", "") or cfg.get("project")
         if not project:
             profile_name = os.path.basename(str(kwargs.get("hermes_home", "")))
             project = f"hermes-{profile_name}" if profile_name not in {"", ".hermes"} else "default"
diff --git a/plugins/memory/supermemory/__init__.py b/plugins/memory/supermemory/__init__.py
index ee6a1c8717..49e8362e92 100644
--- a/plugins/memory/supermemory/__init__.py
+++ b/plugins/memory/supermemory/__init__.py
@@ -55,8 +55,8 @@ def _sanitize_tag(raw: str) -> str:
 
 
 def _resolve_base_url(config_value: Any = "") -> str:
-    """config > SUPERMEMORY_BASE_URL env var > default (self-hosted support)."""
-    raw = str(config_value or "").strip() or os.environ.get("SUPERMEMORY_BASE_URL", "").strip()
+    """config > SUPERMEMORY_BASE_URL (profile-scoped) > default (self-hosted support)."""
+    raw = str(config_value or "").strip() or (get_secret("SUPERMEMORY_BASE_URL", "") or "").strip()
     return (raw or _DEFAULT_BASE_URL).rstrip("/") or _DEFAULT_BASE_URL
 
 
@@ -247,8 +247,10 @@ def _build_client(api_key: str, config: dict, container_tag: str) -> _Supermemor
 
 
 def _resolve_container_tag(config_tag: str, identity: str) -> str:
-    """SUPERMEMORY_CONTAINER_TAG env > config > default; {identity} expands to the agent identity, then sanitize."""
-    raw_tag = os.environ.get("SUPERMEMORY_CONTAINER_TAG", "").strip() or config_tag
+    """SUPERMEMORY_CONTAINER_TAG (profile-scoped) > config > default; {identity} expands to the agent
+    identity, then sanitize. The container is the data partition, so it must never be borrowed from
+    the default profile's environ under multiplexing."""
+    raw_tag = (get_secret("SUPERMEMORY_CONTAINER_TAG", "") or "").strip() or config_tag
     return _sanitize_tag(raw_tag.replace("{identity}", identity))
 
 
diff --git a/plugins/video_gen/xai/__init__.py b/plugins/video_gen/xai/__init__.py
index 8365116bbc..13d59da699 100644
--- a/plugins/video_gen/xai/__init__.py
+++ b/plugins/video_gen/xai/__init__.py
@@ -13,7 +13,6 @@ import asyncio
 import base64
 import logging
 import mimetypes
-import os
 import uuid
 from contextlib import closing
 from pathlib import Path
@@ -66,10 +65,13 @@ def _xai_http(helper: str, fallback: Any, *args: Any, log: Optional[str] = None)
 
 
 def _resolve_xai_credentials() -> Tuple[str, str]:
-    """``(api_key, base_url)``: runtime xai-oauth pool entry → ``auth.json`` OAuth tokens → ``XAI_API_KEY`` (empty key = none; callers check)."""
+    """``(api_key, base_url)``: runtime xai-oauth pool entry → ``auth.json`` OAuth tokens → ``XAI_API_KEY``
+    (empty key = none; callers check). ``resolve_xai_http_credentials`` already applies the profile
+    secret scope to both fields, so a miss stays a miss: a raw ``os.getenv`` fallback here would hand a
+    multiplexed secondary the default profile's key after the scoped resolver correctly returned none."""
     creds = _xai_http("resolve_xai_http_credentials", {}, log="xAI credential resolver failed: %s") or {}
-    base_url = str(creds.get("base_url") or os.getenv("XAI_BASE_URL") or DEFAULT_XAI_BASE_URL)
-    return str(creds.get("api_key") or os.getenv("XAI_API_KEY", "")).strip(), base_url.strip().rstrip("/")
+    base_url = str(creds.get("base_url") or DEFAULT_XAI_BASE_URL)
+    return str(creds.get("api_key") or "").strip(), base_url.strip().rstrip("/")
 
 
 def _xai_headers(api_key: str) -> Dict[str, str]:
diff --git a/tests/agent/test_i18n.py b/tests/agent/test_i18n.py
index 57ed20300f..d319e42c72 100644
--- a/tests/agent/test_i18n.py
+++ b/tests/agent/test_i18n.py
@@ -89,10 +89,34 @@ def test_default_when_nothing_set(monkeypatch):
     monkeypatch.delenv("HERMES_LANGUAGE", raising=False)
     # Force config lookup to return None -- patch the cached reader.
     i18n.reset_language_cache()
-    monkeypatch.setattr(i18n, "_config_language_cached", lambda: None)
+    monkeypatch.setattr(i18n, "_config_language", lambda: None)
     assert i18n.get_language() == "en"
 
 
+def test_language_is_per_profile_under_multiplex(monkeypatch, tmp_path):
+    """HERMES_LANGUAGE in the DEFAULT profile's environ must not leak into a secondary profile's
+    turn, and the config-language cache must not freeze one profile's ``display.language`` for all."""
+    from agent import secret_scope
+
+    default_home = tmp_path / "default"; default_home.mkdir()
+    prof_b = tmp_path / "b"; prof_b.mkdir()
+    (default_home / "config.yaml").write_text("display:\n  language: fr\n")
+    (prof_b / "config.yaml").write_text("display:\n  language: de\n")
+    monkeypatch.setenv("HERMES_LANGUAGE", "zh")  # default profile's .env, bridged into environ
+    i18n.reset_language_cache()
+    secret_scope.set_multiplex_active(True)
+    token = secret_scope.set_secret_scope({})
+    try:
+        monkeypatch.setenv("HERMES_HOME", str(default_home))
+        assert i18n.get_language() == "fr"  # scoped miss: env ignored, this profile's config wins
+        monkeypatch.setenv("HERMES_HOME", str(prof_b))
+        assert i18n.get_language() == "de"  # not the first profile's cached "fr"
+    finally:
+        secret_scope.reset_secret_scope(token)
+        secret_scope.set_multiplex_active(False)
+        i18n.reset_language_cache()
+
+
 # ---------------------------------------------------------------------------
 # t() semantics
 # ---------------------------------------------------------------------------
diff --git a/tests/agent/test_inline_session_search_profile.py b/tests/agent/test_inline_session_search_profile.py
new file mode 100644
index 0000000000..62a31804a7
--- /dev/null
+++ b/tests/agent/test_inline_session_search_profile.py
@@ -0,0 +1,45 @@
+"""The inline ``session_search`` executor forwards ``profile`` so a routed gateway agent can read a
+named profile's store instead of silently searching the injected (default) DB (#82903).
+
+The gateway hard-injects ``db=agent._get_session_db_for_recall()``; without ``profile`` reaching
+``tools.session_search_tool.session_search`` the tool's ``_resolve_profile_db`` never runs and
+``profile="llm-wiki"`` returns the same rows as no profile at all.
+"""
+
+import json
+from pathlib import Path
+from types import SimpleNamespace
+
+from agent.inline_tool_executors import INLINE_TOOL_EXECUTORS, InlineToolContext
+from hermes_state import SessionDB
+
+
+def test_session_search_honours_requested_profile_db(tmp_path, monkeypatch):
+    hermes_home = tmp_path / ".hermes"
+    profile_home = hermes_home / "profiles" / "llm-wiki"
+    profile_home.mkdir(parents=True)
+    monkeypatch.setattr(Path, "home", lambda: tmp_path)
+    monkeypatch.setenv("HERMES_HOME", str(hermes_home))
+
+    current_db = SessionDB(hermes_home / "state.db")
+    current_db.create_session("default-session", source="gateway")
+    current_db.append_message("default-session", role="user", content="weekly report default")
+    current_db._conn.commit()
+    profile_db = SessionDB(profile_home / "state.db")
+    profile_db.create_session("profile-session", source="cli")
+    profile_db.append_message("profile-session", role="user", content="weekly report llm wiki")
+    profile_db._conn.commit()
+    profile_db.close()
+
+    agent = SimpleNamespace(_get_session_db_for_recall=lambda: current_db, session_id="gw-1")
+    ctx = InlineToolContext(effective_task_id="task-1", tool_call_id="call-1")
+    try:
+        routed = json.loads(INLINE_TOOL_EXECUTORS["session_search"](
+            agent, {"query": "weekly report", "profile": "llm-wiki"}, ctx))
+        missing = json.loads(INLINE_TOOL_EXECUTORS["session_search"](
+            agent, {"query": "weekly report", "profile": "missing-profile"}, ctx))
+    finally:
+        current_db.close()
+
+    assert [r["session_id"] for r in routed["results"]] == ["profile-session"]
+    assert missing["success"] is False and "default-session" not in json.dumps(missing)
diff --git a/tests/agent/test_multiplex_base_url_scope.py b/tests/agent/test_multiplex_base_url_scope.py
new file mode 100644
index 0000000000..100a2ca5d7
--- /dev/null
+++ b/tests/agent/test_multiplex_base_url_scope.py
@@ -0,0 +1,65 @@
+"""Multiplex invariant: a scoped API key is never paired with the DEFAULT profile's base URL / proxy.
+
+`agent/auxiliary_client.py` already scopes provider keys via ``_scoped_key_env``; the base URLs beside
+them (OPENAI_BASE_URL, XAI_BASE_URL, NOUS_INFERENCE_BASE_URL) and the gateway proxy URL / browser
+provider endpoints must follow the same rule, or a secondary's key is sent to another profile's host.
+"""
+from __future__ import annotations
+
+import pytest
+
+from agent import secret_scope
+
+
+@pytest.fixture
+def secondary_scope(monkeypatch):
+    for name in ("OPENAI_BASE_URL", "XAI_BASE_URL", "HERMES_XAI_BASE_URL", "NOUS_INFERENCE_BASE_URL",
+                 "GATEWAY_PROXY_URL", "FIRECRAWL_API_URL", "BROWSERBASE_BASE_URL", "XAI_API_KEY"):
+        monkeypatch.setenv(name, f"https://{name.lower()}.default.example/v1")
+    secret_scope.set_multiplex_active(True)
+    token = secret_scope.set_secret_scope({"BROWSERBASE_API_KEY": "bb-b", "BROWSERBASE_PROJECT_ID": "pid-b"})
+    try:
+        yield
+    finally:
+        secret_scope.reset_secret_scope(token)
+        secret_scope.set_multiplex_active(False)
+
+
+def test_base_urls_follow_the_scoped_key_not_default_environ(monkeypatch, secondary_scope, tmp_path):
+    import agent.auxiliary_client as aux
+    import plugins.browser.browserbase.provider as browserbase
+    import plugins.browser.firecrawl.provider as firecrawl
+    import plugins.video_gen.xai as xai_video
+    from gateway.run_turn import GatewayTurnMixin
+    from hermes_cli import auth_nous
+
+    monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+    monkeypatch.setattr(aux, "_get_named_custom_provider", lambda name: None, raising=False)
+
+    _, base = aux._expand_direct_api_alias("openai", None)
+    assert "default.example" not in (base or "")
+    assert aux._scoped_key_env("OPENAI_BASE_URL") == ""
+    assert auth_nous._nous_inference_env_override() is None
+    monkeypatch.setattr("gateway.run._load_gateway_config", lambda: {})
+    assert GatewayTurnMixin._get_proxy_url(GatewayTurnMixin.__new__(GatewayTurnMixin)) is None
+    assert "default.example" not in browserbase.BrowserbaseBrowserProvider()._get_config_or_none()["base_url"]
+    assert "default.example" not in firecrawl.FirecrawlBrowserProvider()._api_url()
+    # xAI video: a scoped miss stays a miss — no environ fallback-after-miss for the key or the URL.
+    api_key, base_url = xai_video._resolve_xai_credentials()
+    assert api_key == "" and "default.example" not in base_url
+
+
+def test_unscoped_single_profile_reads_keep_environ(monkeypatch):
+    """Multiplex OFF (CLI / single gateway): environ IS the profile's own value — behaviour unchanged."""
+    from gateway.run_turn import GatewayTurnMixin
+    from hermes_cli import auth_nous
+
+    secret_scope.set_multiplex_active(False)
+    token = secret_scope.set_secret_scope(None)
+    try:
+        monkeypatch.setenv("GATEWAY_PROXY_URL", "https://proxy.mine.example/")
+        monkeypatch.setenv("NOUS_INFERENCE_BASE_URL", "https://nous.mine.example/v1/")
+        assert GatewayTurnMixin._get_proxy_url(GatewayTurnMixin.__new__(GatewayTurnMixin)) == "https://proxy.mine.example"
+        assert auth_nous._nous_inference_env_override() == "https://nous.mine.example/v1"
+    finally:
+        secret_scope.reset_secret_scope(token)
diff --git a/tests/agent/test_outbound_webhooks.py b/tests/agent/test_outbound_webhooks.py
index 39c8a25221..955c56468d 100644
--- a/tests/agent/test_outbound_webhooks.py
+++ b/tests/agent/test_outbound_webhooks.py
@@ -246,6 +246,24 @@ class TestParseConfig:
         )
         assert targets[0].secret is None
 
+    def test_secret_env_resolves_from_profile_scope_under_multiplex(self, monkeypatch):
+        """Per-profile registration: a secondary's ``.env`` secret signs its deliveries; the DEFAULT
+        profile's environ value must never be borrowed when the secondary's scope lacks the var."""
+        from agent import secret_scope
+
+        monkeypatch.setenv("MY_HOOK_SECRET", "from-default-profile-env")
+        secret_scope.set_multiplex_active(True)
+        token = secret_scope.set_secret_scope({"MY_HOOK_SECRET": "from-secondary-scope"})
+        try:
+            raw = _cfg({"url": "https://example.com", "events": ["on_session_end"], "secret_env": "MY_HOOK_SECRET"})
+            assert outbound_webhooks.iter_configured_targets(raw)[0].secret == "from-secondary-scope"
+            secret_scope.reset_secret_scope(token)
+            token = secret_scope.set_secret_scope({})
+            assert outbound_webhooks.iter_configured_targets(raw)[0].secret is None
+        finally:
+            secret_scope.reset_secret_scope(token)
+            secret_scope.set_multiplex_active(False)
+
 
 # ── matcher behaviour ─────────────────────────────────────────────────────
 
diff --git a/tests/gateway/test_agent_cache_release_profile_scope.py b/tests/gateway/test_agent_cache_release_profile_scope.py
new file mode 100644
index 0000000000..c02e830258
--- /dev/null
+++ b/tests/gateway/test_agent_cache_release_profile_scope.py
@@ -0,0 +1,67 @@
+"""Multiplex invariant: agent-cache eviction commits end-of-session memory under the OWNING profile.
+
+``_spawn_release_thread`` used to start a bare ``threading.Thread``; threads begin with an EMPTY
+context, so provider ``on_session_end`` (credentials/home read at call time) ran under the launch
+profile — a secondary's transcript was extracted into the default profile's memory namespace, or
+failed closed (``UnscopedSecretError``) and the memories were lost.
+"""
+from __future__ import annotations
+
+import threading
+from pathlib import Path
+from types import SimpleNamespace
+
+from agent import secret_scope
+from gateway.config import GatewayConfig
+from gateway.run import GatewayRunner
+from hermes_constants import get_hermes_home
+
+
+def _runner(profile_homes: dict[str, Path]) -> GatewayRunner:
+    runner = GatewayRunner.__new__(GatewayRunner)
+    runner.config = GatewayConfig(multiplex_profiles=True)
+    runner.session_store = SimpleNamespace(_profile_home_for_key=lambda key: profile_homes.get(key))
+    return runner
+
+
+def _seen_after_release(runner, key, *, wait_scope=None) -> dict:
+    seen: dict = {}
+    done = threading.Event()
+
+    def target(agent, k):
+        seen["scope"] = secret_scope.current_secret_scope()
+        seen["home"] = get_hermes_home()
+        done.set()
+
+    runner._spawn_release_thread(target, (None, key), f"t-{key}", inline_fallback=False, session_key=key)
+    assert done.wait(5)
+    return seen
+
+
+def test_unscoped_housekeeping_sweep_enters_the_owning_profile_scope(tmp_path, monkeypatch):
+    default_home = tmp_path / ".hermes"
+    prof_b = default_home / "profiles" / "b"
+    prof_b.mkdir(parents=True)
+    (prof_b / ".env").write_text("HINDSIGHT_LLM_API_KEY=key-of-b\n")
+    monkeypatch.setenv("HERMES_HOME", str(default_home))
+    secret_scope.set_multiplex_active(True)
+    try:
+        # The housekeeping watcher runs with NO scope installed.
+        assert secret_scope.current_secret_scope() is None
+        seen = _seen_after_release(_runner({"agent:b:telegram:dm:1": prof_b}), "agent:b:telegram:dm:1")
+    finally:
+        secret_scope.set_multiplex_active(False)
+    assert seen["home"] == prof_b
+    assert seen["scope"] and seen["scope"].get("HINDSIGHT_LLM_API_KEY") == "key-of-b"
+
+
+def test_in_turn_cap_eviction_keeps_the_callers_scope(tmp_path, monkeypatch):
+    monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+    secret_scope.set_multiplex_active(True)
+    token = secret_scope.set_secret_scope({"MARKER": "turn-scope"})
+    try:
+        seen = _seen_after_release(_runner({}), "agent:main:cli:1")
+    finally:
+        secret_scope.reset_secret_scope(token)
+        secret_scope.set_multiplex_active(False)
+    assert seen["scope"] == {"MARKER": "turn-scope"}
diff --git a/tests/plugins/memory/test_multiplex_memory_identity_scope.py b/tests/plugins/memory/test_multiplex_memory_identity_scope.py
new file mode 100644
index 0000000000..49f5e854f6
--- /dev/null
+++ b/tests/plugins/memory/test_multiplex_memory_identity_scope.py
@@ -0,0 +1,96 @@
+"""Multiplex invariant: memory-provider identity/tenant/endpoint never comes from the default profile.
+
+Under ``gateway.multiplex_profiles`` ``os.environ`` is the DEFAULT profile's ``.env``. When a secondary
+profile's scope does not define MEM0_USER_ID / SUPERMEMORY_CONTAINER_TAG / RETAINDB_PROJECT /
+OPENVIKING_* / HINDSIGHT_BANK_ID / HERMES_HONCHO_HOST, the provider must fall back to its own default
+(per-profile partition), NOT write the secondary's memories into the default profile's account.
+"""
+from __future__ import annotations
+
+import pytest
+
+from agent import secret_scope
+
+_DEFAULT_ENV = {
+    "MEM0_USER_ID": "user-default", "MEM0_AGENT_ID": "agent-default", "MEM0_HOST": "http://mem0.default",
+    "MEM0_MODE": "self_hosted",
+    "SUPERMEMORY_CONTAINER_TAG": "tag-default", "SUPERMEMORY_BASE_URL": "https://sm.default",
+    "RETAINDB_PROJECT": "proj-default", "RETAINDB_BASE_URL": "https://rdb.default",
+    "OPENVIKING_API_KEY": "ov-default", "OPENVIKING_ACCOUNT": "acct-default", "OPENVIKING_USER": "user-default",
+    "OPENVIKING_AGENT": "agent-default", "OPENVIKING_ENDPOINT": "http://ov.default",
+    "HINDSIGHT_BANK_ID": "bank-default", "HINDSIGHT_MODE": "local_external", "HINDSIGHT_API_URL": "http://hs.default",
+    "HERMES_HONCHO_HOST": "host-default", "HONCHO_BASE_URL": "https://honcho.default",
+    "OPENAI_API_KEY": "sk-default", "OPENAI_BASE_URL": "https://openai.default/v1",
+}
+
+
+@pytest.fixture
+def secondary_profile(monkeypatch, tmp_path):
+    """Multiplex ON; default profile's values in environ; secondary profile `b` scope with only its
+    own API keys (no identity/tenant/endpoint vars)."""
+    for k, v in _DEFAULT_ENV.items():
+        monkeypatch.setenv(k, v)
+    home = tmp_path / ".hermes"
+    prof_b = home / "profiles" / "b"
+    prof_b.mkdir(parents=True)
+    (prof_b / "config.yaml").write_text("{}\n")
+    monkeypatch.setenv("HERMES_HOME", str(prof_b))
+    secret_scope.set_multiplex_active(True)
+    token = secret_scope.set_secret_scope({"RETAINDB_API_KEY": "rdb-b", "SUPERMEMORY_API_KEY": "sm-b",
+                                           "HONCHO_API_KEY": "honcho-b", "MEM0_API_KEY": "mem0-b"})
+    try:
+        yield prof_b
+    finally:
+        secret_scope.reset_secret_scope(token)
+        secret_scope.set_multiplex_active(False)
+
+
+def test_secondary_profile_memory_identity_never_inherits_default_environ(secondary_profile):
+    import plugins.memory.hindsight as hindsight
+    import plugins.memory.mem0 as mem0
+    import plugins.memory.openviking as openviking
+    import plugins.memory.retaindb as retaindb
+    import plugins.memory.supermemory as supermemory
+    from plugins.memory.honcho import client as honcho_client
+
+    cfg = mem0._load_config()
+    assert "user_id" not in cfg  # falls back to the gateway-native id, not the default's user
+    assert (cfg["agent_id"], cfg["host"], cfg["mode"]) == ("hermes", "", "platform")
+
+    assert supermemory._resolve_container_tag("cfg_tag", "id") == "cfg_tag"
+    assert "default" not in supermemory._resolve_base_url("")
+
+    provider = retaindb.RetainDBMemoryProvider()
+    provider.initialize("s1", hermes_home=str(secondary_profile))
+    assert provider._client.project == "hermes-b"
+    assert "default" not in provider._client.base_url
+
+    settings = openviking._resolve_connection_settings({})
+    assert (settings["api_key"], settings["account"], settings["user"]) == ("", "", "")
+    assert "default" not in settings["endpoint"]
+    client = openviking._VikingClient("http://x", "k")
+    assert (client._account, client._user) == ("default", "default")  # the built-in tenant, not acct-default
+
+    hcfg = hindsight._load_config()
+    assert (hcfg["banks"]["hermes"]["bankId"], hcfg["mode"]) == ("hermes", "cloud")
+
+    assert honcho_client.resolve_active_host() != "host-default"
+    assert honcho_client._env_base_url() is None
+
+
+def test_mem0_oss_llm_never_borrows_default_profile_openai_key(secondary_profile):
+    pytest.importorskip("mem0")
+    from mem0.configs.llms.openai import OpenAIConfig
+
+    from plugins.memory.mem0._openai_llm import DirectOpenAILLM
+
+    with pytest.raises(ValueError, match="OpenAI API key is required"):
+        DirectOpenAILLM(OpenAIConfig(model="gpt-5-mini"))
+    # The secondary's own scoped key + base URL are used when present.
+    token = secret_scope.set_secret_scope({"OPENAI_API_KEY": "sk-b", "OPENAI_BASE_URL": "https://openai.b/v1"})
+    try:
+        llm = DirectOpenAILLM(OpenAIConfig(model="gpt-5-mini"))
+    finally:
+        secret_scope.reset_secret_scope(token)
+    assert llm.client.api_key == "sk-b"
+    assert str(llm.client.base_url).startswith("https://openai.b/v1")
diff --git a/tests/tools/test_multiplex_tool_credential_scope.py b/tests/tools/test_multiplex_tool_credential_scope.py
new file mode 100644
index 0000000000..926da71b59
--- /dev/null
+++ b/tests/tools/test_multiplex_tool_credential_scope.py
@@ -0,0 +1,56 @@
+"""Multiplex invariant: tool-side profile credentials / targets never leak from the default profile.
+
+Under ``gateway.multiplex_profiles`` ``os.environ`` holds the DEFAULT profile's ``.env``; a secondary
+profile's turn runs with a secret scope that may not define a var at all. Every reader below must
+then see "unset", never the default profile's value (`agent/secret_scope.py::get_secret` contract).
+"""
+from __future__ import annotations
+
+import pytest
+
+from agent import secret_scope
+
+
+@pytest.fixture
+def secondary_scope(monkeypatch):
+    """Multiplex ON with a secondary profile's (empty) secret scope installed."""
+    secret_scope.set_multiplex_active(True)
+    token = secret_scope.set_secret_scope({})
+    try:
+        yield
+    finally:
+        secret_scope.reset_secret_scope(token)
+        secret_scope.set_multiplex_active(False)
+
+
+def test_scoped_tool_credential_gates_ignore_default_profile_environ(monkeypatch, secondary_scope, tmp_path):
+    from tools import browser_use_cli, read_extract, tool_backend_helpers
+
+    monkeypatch.setenv("FIRECRAWL_API_KEY", "fc-default")
+    monkeypatch.setenv("MODAL_TOKEN_ID", "id-default")
+    monkeypatch.setenv("MODAL_TOKEN_SECRET", "secret-default")
+    monkeypatch.setenv("BROWSER_USE_API_KEY", "bu-default")
+    monkeypatch.setattr(tool_backend_helpers.Path, "home", lambda: tmp_path)  # no ~/.modal.toml
+
+    enabled, api_key, _ = read_extract._hosted_ocr_config()
+    assert (enabled, api_key) == (False, None)
+    assert tool_backend_helpers.has_direct_modal_credentials() is False
+    assert browser_use_cli.is_legacy_browser_use_cloud_config({"cloud_provider": "browser-use"}) is False
+
+
+def test_weixin_home_channel_resolves_from_profile_scope_not_environ(monkeypatch, secondary_scope):
+    from tools import send_message_tool
+
+    class _NoHome:
+        def get_home_channel(self, platform):
+            return None
+
+    monkeypatch.setenv("WEIXIN_HOME_CHANNEL", "wx-default-chat")
+    chat_id, err = send_message_tool._home_chat_id(_NoHome(), None, "weixin")
+    assert chat_id is None and err
+    # The secondary's own .env value is honoured.
+    token = secret_scope.set_secret_scope({"WEIXIN_HOME_CHANNEL": "wx-secondary-chat"})
+    try:
+        assert send_message_tool._home_chat_id(_NoHome(), None, "weixin") == ("wx-secondary-chat", None)
+    finally:
+        secret_scope.reset_secret_scope(token)
diff --git a/tools/browser_use_cli.py b/tools/browser_use_cli.py
index 8689efe52e..3b80646dae 100644
--- a/tools/browser_use_cli.py
+++ b/tools/browser_use_cli.py
@@ -198,7 +198,9 @@ def is_legacy_browser_use_cloud_config(browser_cfg: dict) -> bool:
     provider = str(browser_cfg.get("cloud_provider") or "").strip().lower()
     if provider not in {"browser-use", ""} or _use_gateway(browser_cfg) or _camofox_active(" during migration"):
         return False
-    return bool(os.getenv("BROWSER_USE_API_KEY"))
+    # Profile credential: a multiplexed secondary must not inherit the default's cloud mode.
+    from agent.secret_scope import get_secret
+    return bool(get_secret("BROWSER_USE_API_KEY", ""))
 
 
 def is_browser_use_cli_mode() -> bool:
diff --git a/tools/read_extract.py b/tools/read_extract.py
index 0ae70c8ab9..b0e3725350 100644
--- a/tools/read_extract.py
+++ b/tools/read_extract.py
@@ -146,8 +146,10 @@ def _hosted_ocr_config() -> tuple:
     """(enabled, api_key, api_url); never raises, no network. Maintainer decision: the ONLY route
     is a direct ``FIRECRAWL_API_KEY`` (anydoc defaults api_url); the Nous gateway's Parse proxy
     live-probed broken, so it is NOT used. ``file_tools.hosted_ocr: false`` disables even with a
-    key."""
-    api_key = os.environ.get("FIRECRAWL_API_KEY") or None
+    key. The key is a profile credential: read through the secret scope so a multiplexed
+    secondary never spends (or reveals its documents to) the default profile's Firecrawl key."""
+    from agent.secret_scope import get_secret
+    api_key = get_secret("FIRECRAWL_API_KEY") or None
     enabled = api_key is not None
     with contextlib.suppress(Exception):
         from hermes_cli.config import load_config_readonly
diff --git a/tools/send_message_tool.py b/tools/send_message_tool.py
index cfaf016ae7..9b1e549fbc 100644
--- a/tools/send_message_tool.py
+++ b/tools/send_message_tool.py
@@ -305,7 +305,9 @@ def _home_chat_id(config, platform, platform_name):
     home = config.get_home_channel(platform)
     if home:
         return home.chat_id, None
-    wx_home = os.getenv("WEIXIN_HOME_CHANNEL", "").strip() if platform_name == "weixin" else ""
+    # Home channel is a per-profile target like the token beside it: a raw environ read would post a
+    # multiplexed secondary's message into the default profile's Weixin chat.
+    wx_home = (get_secret("WEIXIN_HOME_CHANNEL", "") or "").strip() if platform_name == "weixin" else ""
     if wx_home:
         return wx_home, None
     home_env = _HOME_CHANNEL_ENV_OVERRIDES.get(platform_name, f"{platform_name.upper()}_HOME_CHANNEL")
diff --git a/tools/tool_backend_helpers.py b/tools/tool_backend_helpers.py
index 427a8b3584..52796a180b 100644
--- a/tools/tool_backend_helpers.py
+++ b/tools/tool_backend_helpers.py
@@ -61,8 +61,10 @@ normalize_modal_mode = coerce_modal_mode
 
 
 def has_direct_modal_credentials() -> bool:
-    """Return True when direct Modal credentials/config are available."""
-    if os.getenv("MODAL_TOKEN_ID") and os.getenv("MODAL_TOKEN_SECRET"):
+    """Return True when direct Modal credentials/config are available. The token pair is a
+    profile credential: read it through the secret scope so the default profile's Modal
+    account never selects the direct backend for a multiplexed secondary."""
+    if _scoped_credential("MODAL_TOKEN_ID") and _scoped_credential("MODAL_TOKEN_SECRET"):
         return True
     try:
         return (Path.home() / ".modal.toml").exists()
diff --git a/website/docs/user-guide/multi-profile-gateways.md b/website/docs/user-guide/multi-profile-gateways.md
index 3bba3c2825..fbc691088e 100644
--- a/website/docs/user-guide/multi-profile-gateways.md
+++ b/website/docs/user-guide/multi-profile-gateways.md
@@ -263,6 +263,21 @@ unauthorized-slash operator alert of `P`'s Discord bot (to `P`'s home
 channel). If `P` has no connected bot for that platform the send fails with a
 clear error — it never falls back to the default profile's bot.
 
+Tool and memory-provider credentials follow the same rule. Hosted OCR
+(`FIRECRAWL_API_KEY`), Modal / Browser Use cloud gates, the mem0 OSS OpenAI
+key, xAI video, and every memory-provider identity (`MEM0_USER_ID`,
+`SUPERMEMORY_CONTAINER_TAG`, `RETAINDB_PROJECT`, `OPENVIKING_ACCOUNT/USER`,
+`HINDSIGHT_BANK_ID`, `HERMES_HONCHO_HOST`) are read from the routed profile's
+`.env`, so a secondary profile's memories land in **its** account/bank/project
+(or the provider's per-profile default), never the default profile's. Custom
+endpoints travel with their keys — `OPENAI_BASE_URL`, `XAI_BASE_URL`,
+`NOUS_INFERENCE_BASE_URL`, `GATEWAY_PROXY_URL`, Firecrawl / Browserbase /
+RetainDB / Supermemory / Honcho / Hindsight URLs — so a profile's key is never
+sent to another profile's proxy or self-hosted server. `WEIXIN_HOME_CHANNEL`,
+`HERMES_LANGUAGE` and `display.language`, and `hooks.outbound[].secret_env` are
+likewise per profile, and end-of-session memory extraction for an evicted
+secondary session runs under that profile's scope.
+
 ### Serving selected profiles
 
 By default, `gateway.multiplex_profiles: true` serves every valid named profile