diff --git a/tests/http_layer/test_request_construction.py b/tests/http_layer/test_request_construction.py
index 3232bd8..6ca5100 100644
--- a/tests/http_layer/test_request_construction.py
+++ b/tests/http_layer/test_request_construction.py
@@ -17,7 +17,7 @@ import respx
 
 from tests.conftest import make_tool_fn
 from unraid_mcp.core.client import DEFAULT_TIMEOUT, DISK_TIMEOUT, make_graphql_request
-from unraid_mcp.core.exceptions import ToolError
+from unraid_mcp.core.exceptions import CredentialsNotConfiguredError, ToolError
 
 
 # ---------------------------------------------------------------------------
@@ -32,8 +32,8 @@ API_KEY = "test-api-key-12345"
 def _patch_config():
     """Patch API URL and key for all tests in this module."""
     with (
-        patch("unraid_mcp.core.client.UNRAID_API_URL", API_URL),
-        patch("unraid_mcp.core.client.UNRAID_API_KEY", API_KEY),
+        patch("unraid_mcp.config.settings.UNRAID_API_URL", API_URL),
+        patch("unraid_mcp.config.settings.UNRAID_API_KEY", API_KEY),
     ):
         yield
 
@@ -1288,8 +1288,8 @@ class TestCrossCuttingConcerns:
     async def test_missing_api_url_raises_before_http_call(self) -> None:
         route = respx.post(API_URL).mock(return_value=_graphql_response({}))
         with (
-            patch("unraid_mcp.core.client.UNRAID_API_URL", ""),
-            pytest.raises(ToolError, match="UNRAID_API_URL not configured"),
+            patch("unraid_mcp.config.settings.UNRAID_API_URL", ""),
+            pytest.raises(CredentialsNotConfiguredError),
         ):
             await make_graphql_request("query { online }")
         assert not route.called
@@ -1298,8 +1298,8 @@ class TestCrossCuttingConcerns:
     async def test_missing_api_key_raises_before_http_call(self) -> None:
         route = respx.post(API_URL).mock(return_value=_graphql_response({}))
         with (
-            patch("unraid_mcp.core.client.UNRAID_API_KEY", ""),
-            pytest.raises(ToolError, match="UNRAID_API_KEY not configured"),
+            patch("unraid_mcp.config.settings.UNRAID_API_KEY", ""),
+            pytest.raises(CredentialsNotConfiguredError),
         ):
             await make_graphql_request("query { online }")
         assert not route.called
diff --git a/tests/test_client.py b/tests/test_client.py
index db9629f..a248d5b 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -16,7 +16,7 @@ from unraid_mcp.core.client import (
     make_graphql_request,
     redact_sensitive,
 )
-from unraid_mcp.core.exceptions import ToolError
+from unraid_mcp.core.exceptions import CredentialsNotConfiguredError, ToolError
 
 
 # ---------------------------------------------------------------------------
@@ -173,8 +173,8 @@ class TestMakeGraphQLRequestSuccess:
     @pytest.fixture(autouse=True)
     def _patch_config(self):
         with (
-            patch("unraid_mcp.core.client.UNRAID_API_URL", "https://unraid.local/graphql"),
-            patch("unraid_mcp.core.client.UNRAID_API_KEY", "test-key"),
+            patch("unraid_mcp.config.settings.UNRAID_API_URL", "https://unraid.local/graphql"),
+            patch("unraid_mcp.config.settings.UNRAID_API_KEY", "test-key"),
         ):
             yield
 
@@ -258,22 +258,22 @@ class TestMakeGraphQLRequestErrors:
     @pytest.fixture(autouse=True)
     def _patch_config(self):
         with (
-            patch("unraid_mcp.core.client.UNRAID_API_URL", "https://unraid.local/graphql"),
-            patch("unraid_mcp.core.client.UNRAID_API_KEY", "test-key"),
+            patch("unraid_mcp.config.settings.UNRAID_API_URL", "https://unraid.local/graphql"),
+            patch("unraid_mcp.config.settings.UNRAID_API_KEY", "test-key"),
         ):
             yield
 
     async def test_missing_api_url(self) -> None:
         with (
-            patch("unraid_mcp.core.client.UNRAID_API_URL", ""),
-            pytest.raises(ToolError, match="UNRAID_API_URL not configured"),
+            patch("unraid_mcp.config.settings.UNRAID_API_URL", ""),
+            pytest.raises(CredentialsNotConfiguredError),
         ):
             await make_graphql_request("{ info }")
 
     async def test_missing_api_key(self) -> None:
         with (
-            patch("unraid_mcp.core.client.UNRAID_API_KEY", ""),
-            pytest.raises(ToolError, match="UNRAID_API_KEY not configured"),
+            patch("unraid_mcp.config.settings.UNRAID_API_KEY", ""),
+            pytest.raises(CredentialsNotConfiguredError),
         ):
             await make_graphql_request("{ info }")
 
@@ -377,8 +377,8 @@ class TestGraphQLErrorHandling:
     @pytest.fixture(autouse=True)
     def _patch_config(self):
         with (
-            patch("unraid_mcp.core.client.UNRAID_API_URL", "https://unraid.local/graphql"),
-            patch("unraid_mcp.core.client.UNRAID_API_KEY", "test-key"),
+            patch("unraid_mcp.config.settings.UNRAID_API_URL", "https://unraid.local/graphql"),
+            patch("unraid_mcp.config.settings.UNRAID_API_KEY", "test-key"),
         ):
             yield
 
@@ -641,8 +641,8 @@ class TestRateLimitRetry:
     @pytest.fixture(autouse=True)
     def _patch_config(self):
         with (
-            patch("unraid_mcp.core.client.UNRAID_API_URL", "https://unraid.local/graphql"),
-            patch("unraid_mcp.core.client.UNRAID_API_KEY", "test-key"),
+            patch("unraid_mcp.config.settings.UNRAID_API_URL", "https://unraid.local/graphql"),
+            patch("unraid_mcp.config.settings.UNRAID_API_KEY", "test-key"),
             patch("unraid_mcp.core.client.asyncio.sleep", new_callable=AsyncMock),
         ):
             yield
diff --git a/tests/test_setup.py b/tests/test_setup.py
index 7b25b2c..e861ee0 100644
--- a/tests/test_setup.py
+++ b/tests/test_setup.py
@@ -154,3 +154,23 @@ async def test_elicit_and_configure_returns_false_on_cancel():
 
     result = await elicit_and_configure(mock_ctx)
     assert result is False
+
+
+@pytest.mark.asyncio
+async def test_make_graphql_request_raises_sentinel_when_unconfigured():
+    """make_graphql_request raises CredentialsNotConfiguredError (not ToolError) when
+    credentials are absent, so callers can trigger elicitation."""
+    from unraid_mcp.config import settings as settings_mod
+    from unraid_mcp.core.client import make_graphql_request
+    from unraid_mcp.core.exceptions import CredentialsNotConfiguredError
+
+    original_url = settings_mod.UNRAID_API_URL
+    original_key = settings_mod.UNRAID_API_KEY
+    try:
+        settings_mod.UNRAID_API_URL = None
+        settings_mod.UNRAID_API_KEY = None
+        with pytest.raises(CredentialsNotConfiguredError):
+            await make_graphql_request("{ __typename }")
+    finally:
+        settings_mod.UNRAID_API_URL = original_url
+        settings_mod.UNRAID_API_KEY = original_key
diff --git a/unraid_mcp/core/client.py b/unraid_mcp/core/client.py
index e56defa..8a377d6 100644
--- a/unraid_mcp/core/client.py
+++ b/unraid_mcp/core/client.py
@@ -16,12 +16,10 @@ import httpx
 from ..config.logging import logger
 from ..config.settings import (
     TIMEOUT_CONFIG,
-    UNRAID_API_KEY,
-    UNRAID_API_URL,
     UNRAID_VERIFY_SSL,
     VERSION,
 )
-from ..core.exceptions import ToolError
+from ..core.exceptions import CredentialsNotConfiguredError, ToolError
 from .utils import safe_display_url
 
 
@@ -313,13 +311,15 @@ async def make_graphql_request(
         Dict containing the GraphQL response data
 
     Raises:
+        CredentialsNotConfiguredError: When UNRAID_API_URL or UNRAID_API_KEY are absent at call time
         ToolError: For HTTP errors, network errors, or non-idempotent GraphQL errors
     """
-    if not UNRAID_API_URL:
-        raise ToolError("UNRAID_API_URL not configured")
+    # Local import to get current runtime values — module-level names are captured at import time
+    # and won't reflect runtime changes (e.g., after elicitation sets them via apply_runtime_config).
+    from ..config import settings as _settings
 
-    if not UNRAID_API_KEY:
-        raise ToolError("UNRAID_API_KEY not configured")
+    if not _settings.UNRAID_API_URL or not _settings.UNRAID_API_KEY:
+        raise CredentialsNotConfiguredError()
 
     # Check TTL cache — short-circuits rate limiter on hits
     is_mutation = query.lstrip().startswith("mutation")
@@ -331,14 +331,14 @@ async def make_graphql_request(
 
     headers = {
         "Content-Type": "application/json",
-        "X-API-Key": UNRAID_API_KEY,
+        "X-API-Key": _settings.UNRAID_API_KEY,
     }
 
     payload: dict[str, Any] = {"query": query}
     if variables:
         payload["variables"] = variables
 
-    logger.debug(f"Making GraphQL request to {safe_display_url(UNRAID_API_URL)}:")
+    logger.debug(f"Making GraphQL request to {safe_display_url(_settings.UNRAID_API_URL)}:")
     logger.debug(f"Query: {query[:200]}{'...' if len(query) > 200 else ''}")  # Log truncated query
     if variables:
         logger.debug(f"Variables: {redact_sensitive(variables)}")
@@ -357,7 +357,7 @@ async def make_graphql_request(
 
         response: httpx.Response | None = None
         for attempt in range(3):
-            response = await client.post(UNRAID_API_URL, **post_kwargs)
+            response = await client.post(_settings.UNRAID_API_URL, **post_kwargs)
             if response.status_code == 429:
                 backoff = 2**attempt
                 logger.warning(