diff --git a/hermes_cli/config.py b/hermes_cli/config.py
index 17a1226061b9..f879b05a82ab 100644
--- a/hermes_cli/config.py
+++ b/hermes_cli/config.py
@@ -220,6 +220,11 @@ def ensure_hermes_home():
         # (terminal and execute_code).  Skill-declared required_environment_variables
         # are passed through automatically; this list is for non-skill use cases.
         "env_passthrough": [],
+        # Env var names containing proxy-brokered placeholders (not real secrets)
+        # that should bypass the provider-secret blocklist. For runtimes like
+        # NVIDIA OpenShell where a network proxy rewrites placeholder values
+        # with real credentials on egress (e.g. SLACK_BOT_TOKEN, SLACK_APP_TOKEN).
+        "proxy_credentials": [],
         "docker_image": "nikolaik/python-nodejs:python3.11-nodejs20",
         "docker_forward_env": [],
         "singularity_image": "docker://nikolaik/python-nodejs:python3.11-nodejs20",
diff --git a/tools/environments/local.py b/tools/environments/local.py
index 27282b6ef67a..b73f7d5c79e6 100644
--- a/tools/environments/local.py
+++ b/tools/environments/local.py
@@ -130,6 +130,29 @@ def _build_provider_env_blocklist() -> frozenset:
 
 _HERMES_PROVIDER_ENV_BLOCKLIST = _build_provider_env_blocklist()
 
+# Guard so proxy_credentials registration runs only once, not on every subprocess call.
+_proxy_credentials_registered = False
+
+
+def _ensure_proxy_credentials_registered() -> None:
+    """Register proxy_credentials from config into env_passthrough (once).
+
+    Called from both _sanitize_subprocess_env and _make_run_env so that
+    whichever path runs first triggers registration.
+    """
+    global _proxy_credentials_registered
+    if _proxy_credentials_registered:
+        return
+    try:
+        from cli import CLI_CONFIG
+        proxy_creds = CLI_CONFIG.get("terminal", {}).get("proxy_credentials", [])
+        if proxy_creds:
+            from tools.env_passthrough import register_env_passthrough
+            register_env_passthrough(proxy_creds)
+    except ImportError:
+        pass
+    _proxy_credentials_registered = True
+
 
 def _sanitize_subprocess_env(base_env: dict | None, extra_env: dict | None = None) -> dict:
     """Filter Hermes-managed secrets from a subprocess environment.
@@ -139,6 +162,8 @@ def _sanitize_subprocess_env(base_env: dict | None, extra_env: dict | None = Non
     :mod:`tools.env_passthrough` (skill-declared or user-configured) also
     bypass the blocklist.
     """
+    _ensure_proxy_credentials_registered()
+
     try:
         from tools.env_passthrough import is_env_passthrough as _is_passthrough
     except Exception:
@@ -271,6 +296,7 @@ def _is_noise(line: str) -> bool:
 
 def _make_run_env(env: dict) -> dict:
     """Build a run environment with a sane PATH and provider-var stripping."""
+    _ensure_proxy_credentials_registered()
     try:
         from tools.env_passthrough import is_env_passthrough as _is_passthrough
     except Exception: