diff --git a/roboco/services/llm.py b/roboco/services/llm.py
index 6e5fde25..98512d0e 100644
--- a/roboco/services/llm.py
+++ b/roboco/services/llm.py
@@ -116,6 +116,12 @@ class _ResolvedAssignment:
     model_name: str
 
 
+# The two human-facing interactive roles (held-open chat sessions). Kept as a
+# literal here — not imported from runtime.orchestrator — to avoid a service →
+# orchestrator import cycle; the slugs are stable seed identities.
+_INTERACTIVE_AGENT_SLUGS = frozenset({"intake-1", "secretary-1"})
+
+
 class ModelRoutingService(BaseService):
     """Resolves per-agent routes from `model_assignments` + legacy fallback."""
 
@@ -134,9 +140,34 @@ class ModelRoutingService(BaseService):
         if resolved is not None and resolved.provider.enabled:
             route = await self._route_from_resolved(resolved, agent_slug)
             if route is not None:
-                return route
+                return self._guard_interactive(route, agent_slug, role)
         return self._legacy_route(role)
 
+    def _guard_interactive(
+        self, route: AgentRoute, agent_slug: str, role: str
+    ) -> AgentRoute:
+        """Keep the human-facing interactive roles off GROK for now.
+
+        intake (prompter) and secretary run a held-open chat the human types
+        into, driven by the Claude Agent SDK. GROK has no interactive runtime
+        yet, and the interactive spawn injects the route's creds as
+        ``ANTHROPIC_*`` against ``api.x.ai/v1`` — the wrong protocol — yielding a
+        silent, empty reply. Until the opencode interactive driver lands,
+        downgrade a GROK route for these slugs to the Anthropic default. (The
+        one-shot delivery roles route to GROK unchanged.)
+        """
+        if (
+            route.provider_type == ModelProvider.GROK
+            and agent_slug in _INTERACTIVE_AGENT_SLUGS
+        ):
+            self.log.warning(
+                "GROK route for an interactive role downgraded to Anthropic "
+                "(no Grok interactive runtime yet)",
+                agent_slug=agent_slug,
+            )
+            return self._legacy_route(role)
+        return route
+
     async def _resolve_assignment(
         self, agent_slug: str, role: str
     ) -> _ResolvedAssignment | None:
diff --git a/tests/unit/services/test_llm_routing_interactive_guard.py b/tests/unit/services/test_llm_routing_interactive_guard.py
new file mode 100644
index 00000000..994cfeab
--- /dev/null
+++ b/tests/unit/services/test_llm_routing_interactive_guard.py
@@ -0,0 +1,60 @@
+"""The interactive-role routing guard keeps intake/secretary off GROK.
+
+GROK has no interactive runtime yet, and the interactive spawn would inject the
+route's creds as ANTHROPIC_* against api.x.ai/v1 (wrong protocol → silent empty
+reply). Until the opencode interactive driver lands, a GROK route for those
+slugs is downgraded to the Anthropic default. The one-shot delivery roles route
+to GROK unchanged. DB-free: exercises `_guard_interactive` directly.
+"""
+
+from __future__ import annotations
+
+import structlog
+from roboco.models.base import ModelProvider
+from roboco.services.llm import AgentRoute, ModelRoutingService
+
+
+def _svc() -> ModelRoutingService:
+    svc = ModelRoutingService.__new__(ModelRoutingService)
+    svc.log = structlog.get_logger()
+    return svc
+
+
+def _grok_route() -> AgentRoute:
+    return AgentRoute(
+        provider_id=None,
+        provider_type=ModelProvider.GROK,
+        base_url="https://api.x.ai/v1",
+        auth_token="xai-key",
+        model_name="grok-build-0.1",
+    )
+
+
+def test_grok_interactive_role_downgrades_to_anthropic() -> None:
+    svc = _svc()
+    for slug in ("intake-1", "secretary-1"):
+        route = svc._guard_interactive(_grok_route(), slug, "prompter")
+        assert route.provider_type == ModelProvider.ANTHROPIC
+        # No xAI creds leak onto the Claude SDK path.
+        assert route.base_url is None
+        assert route.auth_token is None
+
+
+def test_grok_delivery_role_is_left_on_grok() -> None:
+    svc = _svc()
+    route = svc._guard_interactive(_grok_route(), "be-dev-1", "developer")
+    assert route.provider_type == ModelProvider.GROK
+    assert route.base_url == "https://api.x.ai/v1"
+
+
+def test_non_grok_interactive_route_is_unchanged() -> None:
+    svc = _svc()
+    anthropic = AgentRoute(
+        provider_id=None,
+        provider_type=ModelProvider.ANTHROPIC,
+        base_url=None,
+        auth_token=None,
+        model_name="claude-opus-4-6",
+    )
+    route = svc._guard_interactive(anthropic, "intake-1", "prompter")
+    assert route is anthropic