diff --git a/nanobot/cli/onboard.py b/nanobot/cli/onboard.py
index 1185f851..7104ae69 100644
--- a/nanobot/cli/onboard.py
+++ b/nanobot/cli/onboard.py
@@ -1612,6 +1612,13 @@ def _quick_start_requires_api_key(provider_name: str, info: _QuickStartProviderI
     return provider_name == "custom" or not (info and (info.is_local or info.is_oauth))
 
 
+def _quick_start_codex_proxy(config: Config) -> str | None:
+    """Resolve only the Codex proxy without validating unrelated provider secrets."""
+    proxy_config = Config()
+    proxy_config.providers.openai_codex.proxy = config.providers.openai_codex.proxy
+    return resolve_config_env_vars(proxy_config).providers.openai_codex.proxy or None
+
+
 def _quick_start_oauth_login(config: Config, provider_name: str) -> bool:
     """Authenticate an OAuth provider supported by Quick Start."""
     if provider_name != "openai_codex":
@@ -1625,7 +1632,7 @@ def _quick_start_oauth_login(config: Config, provider_name: str) -> bool:
         return False
 
     try:
-        proxy = resolve_config_env_vars(config).providers.openai_codex.proxy or None
+        proxy = _quick_start_codex_proxy(config)
     except ValueError as exc:
         console.print(f"[red]{exc}[/red]")
         return False
@@ -1662,7 +1669,7 @@ def _quick_start_oauth_is_authenticated(config: Config, provider_name: str) -> b
     try:
         from oauth_cli_kit import get_token
 
-        proxy = resolve_config_env_vars(config).providers.openai_codex.proxy or None
+        proxy = _quick_start_codex_proxy(config)
         token = get_token(proxy=proxy)
     except Exception:
         return False
diff --git a/tests/agent/test_onboard_logic.py b/tests/agent/test_onboard_logic.py
index e1174188..88947862 100644
--- a/tests/agent/test_onboard_logic.py
+++ b/tests/agent/test_onboard_logic.py
@@ -1066,10 +1066,19 @@ class TestMainMenuUpdate:
         import oauth_cli_kit
 
         config = Config()
+        config.providers.openai.api_key = "${UNRELATED_MISSING_KEY}"
+        config.providers.openai_codex.proxy = "${CODEX_PROXY}"
         token = SimpleNamespace(access="existing-token", account_id="account-123")
+        token_proxies: list[str | None] = []
         login_calls: list[object] = []
 
-        monkeypatch.setattr(oauth_cli_kit, "get_token", lambda **kwargs: token)
+        monkeypatch.setenv("CODEX_PROXY", "http://127.0.0.1:8080")
+        monkeypatch.delenv("UNRELATED_MISSING_KEY", raising=False)
+        monkeypatch.setattr(
+            oauth_cli_kit,
+            "get_token",
+            lambda **kwargs: token_proxies.append(kwargs.get("proxy")) or token,
+        )
         monkeypatch.setattr(
             oauth_cli_kit,
             "login_oauth_interactive",
@@ -1078,7 +1087,28 @@ class TestMainMenuUpdate:
         monkeypatch.setattr(onboard_wizard.console, "print", lambda *args, **kwargs: None)
 
         assert onboard_wizard._quick_start_oauth_login(config, "openai_codex") is True
+        assert token_proxies == ["http://127.0.0.1:8080"]
         assert login_calls == []
+        assert config.providers.openai.api_key == "${UNRELATED_MISSING_KEY}"
+        assert config.providers.openai_codex.proxy == "${CODEX_PROXY}"
+
+    def test_quick_start_codex_auth_check_ignores_unrelated_missing_env(self, monkeypatch):
+        """OAuth readiness should depend only on the Codex proxy and token."""
+        import oauth_cli_kit
+
+        config = Config()
+        config.providers.anthropic.api_key = "${UNRELATED_MISSING_KEY}"
+        monkeypatch.delenv("UNRELATED_MISSING_KEY", raising=False)
+        monkeypatch.setattr(
+            oauth_cli_kit,
+            "get_token",
+            lambda **kwargs: SimpleNamespace(access="existing-token"),
+        )
+
+        assert (
+            onboard_wizard._quick_start_oauth_is_authenticated(config, "openai_codex")
+            is True
+        )
 
     def test_quick_start_summary_reports_missing_codex_oauth(self, monkeypatch):
         """The review step should distinguish OAuth from an API-key setup."""