diff --git a/plugins/image_gen/meta-ai/__init__.py b/plugins/image_gen/meta-ai/__init__.py
index 4ea73dd94b..cfc3aea2af 100644
--- a/plugins/image_gen/meta-ai/__init__.py
+++ b/plugins/image_gen/meta-ai/__init__.py
@@ -6,10 +6,9 @@ Selection: ``model`` kwarg → ``META_IMAGE_MODEL`` → ``image_gen.meta-ai.mode
 from __future__ import annotations
 
 import logging
-import os
 from typing import Any, Dict, List, Optional, Tuple
 
-from agent.secret_scope import get_secret
+from agent.secret_scope import get_secret, get_secret_str
 from agent.image_gen_provider import (
     DEFAULT_ASPECT_RATIO, resolve_aspect_ratio, save_b64_image, save_url_image, success_response)
 from plugins.image_gen._common import (
@@ -32,7 +31,9 @@ def _resolve_api_key() -> Optional[str]:
 
 
 def _resolve_base_url() -> str:
-    return (os.environ.get(BASE_URL_ENV) or "").strip() or DEFAULT_BASE_URL
+    # Through the secret scope like the key: under multiplexing os.environ holds the launch profile's
+    # endpoint, and a routed profile's key must never be sent to another profile's base URL.
+    return get_secret_str(BASE_URL_ENV).strip() or DEFAULT_BASE_URL
 
 
 # Model ids are sent verbatim to ``/v1/images/generations``.
diff --git a/plugins/image_gen/openai/__init__.py b/plugins/image_gen/openai/__init__.py
index ca237b3008..f3b90adfeb 100644
--- a/plugins/image_gen/openai/__init__.py
+++ b/plugins/image_gen/openai/__init__.py
@@ -12,7 +12,7 @@ import logging
 import os
 from typing import Any, Dict, List, Optional, Tuple
 
-from agent.secret_scope import get_secret
+from agent.secret_scope import get_secret, get_secret_str
 from agent.image_gen_provider import DEFAULT_ASPECT_RATIO, resolve_aspect_ratio, success_response
 from plugins.image_gen._common import (
     GPT_IMAGE_2_API_MODEL as API_MODEL, GPT_IMAGE_2_DEFAULT as DEFAULT_MODEL, GPT_IMAGE_2_TIERS,
@@ -70,7 +70,7 @@ def _resolve_endpoint() -> Tuple[str, str]:
     named = str(cfg.get("provider") or "").strip()
     named_base, named_key = _named_endpoint(named) if named else ("", "")
     base_url = (str(cfg.get("base_url") or "").strip().rstrip("/") or named_base
-                or os.environ.get("OPENAI_BASE_URL", "").strip())
+                or get_secret_str("OPENAI_BASE_URL").strip())
     key_env = str(cfg.get("key_env") or "").strip()
     api_key = (get_secret(key_env) if key_env else None) or named_key or get_secret("OPENAI_API_KEY") or ""
     return base_url, api_key
diff --git a/tests/plugins/image_gen/test_meta_ai_provider.py b/tests/plugins/image_gen/test_meta_ai_provider.py
index 4fc87c8863..53c278fa67 100644
--- a/tests/plugins/image_gen/test_meta_ai_provider.py
+++ b/tests/plugins/image_gen/test_meta_ai_provider.py
@@ -109,6 +109,24 @@ class TestResolution:
         monkeypatch.setenv("META_BASE_URL", "https://proxy.internal/v1")
         assert meta_plugin._resolve_base_url() == "https://proxy.internal/v1"
 
+    def test_base_url_follows_the_profile_secret_scope(self, monkeypatch):
+        """Under multiplexing os.environ is the launch profile's: a routed profile's key must go to
+        ITS base URL, and a profile without an override gets the default — never the launch URL."""
+        from agent.secret_scope import reset_secret_scope, set_multiplex_active, set_secret_scope
+
+        monkeypatch.setenv("META_BASE_URL", "https://launch.example/v1")
+        set_multiplex_active(True)
+        try:
+            for scope, expected in (({"META_BASE_URL": "https://profile-b.example/v1"}, "https://profile-b.example/v1"),
+                                    ({}, "https://api.meta.ai/v1")):
+                token = set_secret_scope(scope)
+                try:
+                    assert meta_plugin._resolve_base_url() == expected
+                finally:
+                    reset_secret_scope(token)
+        finally:
+            set_multiplex_active(False)
+
 
 # ── Model resolution ──────────────────────────────────────────────────────────