diff --git a/src/operations_center/backends/worker_backend_selector.py b/src/operations_center/backends/worker_backend_selector.py
index 87cd1606..a4ea69ef 100644
--- a/src/operations_center/backends/worker_backend_selector.py
+++ b/src/operations_center/backends/worker_backend_selector.py
@@ -2,6 +2,7 @@
 # Copyright (C) 2026 ProtocolWarden
 from __future__ import annotations
 
+import os
 import re
 from dataclasses import dataclass
 from datetime import UTC, datetime, timedelta
@@ -36,6 +37,12 @@
 _SUPPORTED_WORKER_BACKENDS = ("claude_code", "codex_cli", "aider_local", "direct_local")
 _REMOTE_WORKER_BACKENDS = ("claude_code", "codex_cli")
 _LOCAL_WORKER_BACKENDS = ("aider_local", "direct_local")
+_PROVIDER_TO_WORKER_BACKEND = {
+    "claude": "claude_code",
+    "anthropic": "claude_code",
+    "codex": "codex_cli",
+    "openai": "codex_cli",
+}
 _TIMEZONE_RESET_RE = re.compile(r"resets\s+(\d{1,2}:\d{2}(?:am|pm))\s+\(([^)]+)\)", re.IGNORECASE)
 _ISO_RESET_RE = re.compile(
     r"resets?(?:\s+at)?\s+(\d{4}-\d{2}-\d{2}T\d{2}:\d{2}(?::\d{2})?Z)",
@@ -86,6 +93,18 @@ def worker_backend_observed_runtime(
     }
 
 
+def _allowed_remote_worker_backends() -> tuple[str, ...]:
+    raw = os.environ.get("OPERATIONS_CENTER_ALLOWED_PROVIDERS", "").strip()
+    if not raw:
+        return _REMOTE_WORKER_BACKENDS
+    allowed = {
+        _PROVIDER_TO_WORKER_BACKEND[provider.strip().lower()]
+        for provider in raw.split(",")
+        if provider.strip().lower() in _PROVIDER_TO_WORKER_BACKEND
+    }
+    return tuple(backend for backend in _REMOTE_WORKER_BACKENDS if backend in allowed)
+
+
 def worker_backend_candidates(preferred_backend: str) -> tuple[str, ...]:
     if preferred_backend not in _SUPPORTED_WORKER_BACKENDS:
         return (preferred_backend,)
@@ -94,9 +113,13 @@ def worker_backend_candidates(preferred_backend: str) -> tuple[str, ...]:
     # themselves (currently a set of one, so no fallback until executor services
     # support them natively).
     if preferred_backend in _REMOTE_WORKER_BACKENDS:
-        pool = _REMOTE_WORKER_BACKENDS
+        pool = _allowed_remote_worker_backends()
     else:
         pool = _LOCAL_WORKER_BACKENDS
+    if not pool:
+        return ()
+    if preferred_backend not in pool:
+        return pool
     alternates = tuple(backend for backend in pool if backend != preferred_backend)
     return (preferred_backend, *alternates)
 
@@ -143,6 +166,13 @@ def select_worker_backend(
 ) -> WorkerBackendSelection:
     current = now or datetime.now(UTC)
     candidates = worker_backend_candidates(preferred_backend)
+    if not candidates:
+        return WorkerBackendSelection(
+            preferred_backend=preferred_backend,
+            selected_backend=None,
+            cooldowns={},
+            reason=f"no allowed worker backends for preferred backend {preferred_backend}",
+        )
     cooldowns = {
         backend: _read_worker_backend_cooldown(usage_store, backend, now=current)
         for backend in candidates
diff --git a/tests/unit/backends/test_worker_backend_selector.py b/tests/unit/backends/test_worker_backend_selector.py
index 2e436489..72da6762 100644
--- a/tests/unit/backends/test_worker_backend_selector.py
+++ b/tests/unit/backends/test_worker_backend_selector.py
@@ -19,7 +19,10 @@ def _usage_store() -> SimpleNamespace:
     )
 
 
-def test_select_worker_backend_prefers_alternate_when_preferred_cooling_down() -> None:
+def test_select_worker_backend_prefers_alternate_when_preferred_cooling_down(
+    monkeypatch,
+) -> None:
+    monkeypatch.setenv("OPERATIONS_CENTER_ALLOWED_PROVIDERS", "claude,codex")
     now = datetime(2026, 5, 25, 16, 0, tzinfo=UTC)
 
     def _cooldown(worker_backend: str, *, now):
@@ -40,6 +43,31 @@ def _cooldown(worker_backend: str, *, now):
     assert selection.selected_backend == "codex_cli"
 
 
+def test_select_worker_backend_respects_allowed_provider_env(monkeypatch) -> None:
+    now = datetime(2026, 5, 25, 16, 0, tzinfo=UTC)
+    monkeypatch.setenv("OPERATIONS_CENTER_ALLOWED_PROVIDERS", "claude")
+
+    def _cooldown(worker_backend: str, *, now):
+        if worker_backend == "claude_code":
+            return datetime(2026, 5, 25, 17, 0, tzinfo=UTC)
+        return None
+
+    usage_store = _usage_store()
+    usage_store.worker_backend_cooldown_until = _cooldown
+
+    selection = select_worker_backend(
+        preferred_backend="claude_code",
+        usage_store=usage_store,
+        dynamic_enabled=True,
+        now=now,
+    )
+
+    assert selection.selected_backend is None
+    assert selection.reason is not None
+    assert "claude_code until" in selection.reason
+    assert "codex_cli" not in selection.reason
+
+
 def test_select_worker_backend_not_blocked_by_lone_model_weekly(monkeypatch, tmp_path) -> None:
     # End-to-end with a real UsageStore: a burnt sonnet weekly must leave the
     # claude_code backend selectable (haiku/opus still runnable) rather than
@@ -79,7 +107,10 @@ def test_parse_worker_backend_reset_handles_relative_message() -> None:
     assert reset_at == datetime(2026, 5, 25, 21, 0, tzinfo=UTC)
 
 
-def test_execute_with_worker_backend_round_robin_retries_on_capacity_limit() -> None:
+def test_execute_with_worker_backend_round_robin_retries_on_capacity_limit(
+    monkeypatch,
+) -> None:
+    monkeypatch.setenv("OPERATIONS_CENTER_ALLOWED_PROVIDERS", "claude,codex")
     cooldowns: dict[str, datetime | None] = {"claude_code": None, "codex_cli": None}
     calls: list[str] = []
 
@@ -114,3 +145,43 @@ def _run_once(worker_backend: str):
     assert executed.selected_backend == "codex_cli"
     assert executed.fallback_used is True
     assert calls == ["claude_code", "codex_cli"]
+
+
+def test_round_robin_does_not_fallback_to_disallowed_backend(monkeypatch) -> None:
+    monkeypatch.setenv("OPERATIONS_CENTER_ALLOWED_PROVIDERS", "claude")
+    cooldowns: dict[str, datetime | None] = {"claude_code": None, "codex_cli": None}
+    calls: list[str] = []
+
+    def _cooldown_until(worker_backend: str, *, now):
+        return cooldowns.get(worker_backend)
+
+    def _record(worker_backend: str, reset_at, now) -> None:
+        cooldowns[worker_backend] = reset_at
+
+    usage_store = _usage_store()
+    usage_store.worker_backend_cooldown_until = _cooldown_until
+    usage_store.record_worker_backend_cooldown = _record
+
+    def _run_once(worker_backend: str):
+        calls.append(worker_backend)
+        return {
+            "status": "failed",
+            "error_summary": "usage limit hit, please try again in 5h 0m",
+        }
+
+    executed = execute_with_worker_backend_round_robin(
+        preferred_backend="claude_code",
+        usage_store=usage_store,
+        dynamic_enabled=True,
+        execute_once=_run_once,
+        failed=lambda payload: payload["status"] != "succeeded",
+        failure_text=lambda payload: payload.get("error_summary"),
+    )
+
+    assert executed.selected_backend == "claude_code"
+    assert executed.fallback_used is False
+    assert executed.selection.selected_backend is None
+    assert executed.selection.reason is not None
+    assert "claude_code until" in executed.selection.reason
+    assert "codex_cli" not in executed.selection.reason
+    assert calls == ["claude_code"]
diff --git a/tests/unit/backends/test_worker_backend_selector_cov.py b/tests/unit/backends/test_worker_backend_selector_cov.py
index f84b7332..68d25213 100644
--- a/tests/unit/backends/test_worker_backend_selector_cov.py
+++ b/tests/unit/backends/test_worker_backend_selector_cov.py
@@ -23,6 +23,11 @@
 NOW = datetime(2026, 6, 2, 12, 0, 0, tzinfo=UTC)
 
 
+@pytest.fixture(autouse=True)
+def _allow_all_remote_worker_backends(monkeypatch) -> None:
+    monkeypatch.setenv("OPERATIONS_CENTER_ALLOWED_PROVIDERS", "claude,codex")
+
+
 # --------------------------------------------------------------------------
 # worker_backend_candidates
 # --------------------------------------------------------------------------