diff --git a/trustgraph-base/trustgraph/schema/services/tool_service.py b/trustgraph-base/trustgraph/schema/services/tool_service.py
new file mode 100644
index 00000000..18315f29
--- /dev/null
+++ b/trustgraph-base/trustgraph/schema/services/tool_service.py
@@ -0,0 +1,25 @@
+
+from dataclasses import dataclass
+
+from ..core.primitives import Error
+
+
+@dataclass
+class ToolServiceRequest:
+    """Request to a dynamically configured tool service."""
+    # User context for multi-tenancy
+    user: str = ""
+    # Config values (collection, etc.) as JSON
+    config: str = ""
+    # Arguments from LLM as JSON
+    arguments: str = ""
+
+
+@dataclass
+class ToolServiceResponse:
+    """Response from a tool service."""
+    error: Error | None = None
+    # Response text (the observation)
+    response: str = ""
+    # End of stream marker for streaming responses
+    end_of_stream: bool = False