Add pooled same-provider credential fallback

tests/test_runtime_provider_resolution.py

@@ -1,6 +1,55 @@
 from hermes_cli import runtime_provider as rp
 
 
+def test_resolve_runtime_provider_uses_credential_pool(monkeypatch):
+    class _Entry:
+        access_token = "pool-token"
+        source = "manual"
+        base_url = "https://chatgpt.com/backend-api/codex"
+
+    class _Pool:
+        def has_credentials(self):
+            return True
+
+        def select(self):
+            return _Entry()
+
+    monkeypatch.setattr(rp, "resolve_provider", lambda *a, **k: "openai-codex")
+    monkeypatch.setattr(rp, "load_pool", lambda provider: _Pool())
+
+    resolved = rp.resolve_runtime_provider(requested="openai-codex")
+
+    assert resolved["provider"] == "openai-codex"
+    assert resolved["api_key"] == "pool-token"
+    assert resolved["credential_pool"] is not None
+    assert resolved["source"] == "manual"
+
+
+def test_resolve_runtime_provider_falls_back_when_pool_empty(monkeypatch):
+    class _Pool:
+        def has_credentials(self):
+            return False
+
+    monkeypatch.setattr(rp, "resolve_provider", lambda *a, **k: "openai-codex")
+    monkeypatch.setattr(rp, "load_pool", lambda provider: _Pool())
+    monkeypatch.setattr(
+        rp,
+        "resolve_codex_runtime_credentials",
+        lambda: {
+            "provider": "openai-codex",
+            "base_url": "https://chatgpt.com/backend-api/codex",
+            "api_key": "codex-token",
+            "source": "hermes-auth-store",
+            "last_refresh": "2026-02-26T00:00:00Z",
+        },
+    )
+
+    resolved = rp.resolve_runtime_provider(requested="openai-codex")
+
+    assert resolved["api_key"] == "codex-token"
+    assert resolved.get("credential_pool") is None
+
+
 def test_resolve_runtime_provider_codex(monkeypatch):
     monkeypatch.setattr(rp, "resolve_provider", lambda *a, **k: "openai-codex")
     monkeypatch.setattr(