diff --git a/agent.py b/agent.py
index 0ef9ab8..5deddfb 100644
--- a/agent.py
+++ b/agent.py
@@ -524,7 +524,7 @@ class CustomerIntegrationEngineer(A2AAgent[CustomerIntegrationEngineerConfig, No
             blocked_actions=blocked_actions,
         )
 
-    @a2a.tool(description="Validate OpenAPI, JSON Schema, and webhook contracts with deterministic fixtures", input_schema=_PUBLIC_REQUEST_SCHEMA, timeout_seconds=120, idempotent=True, max_retries=0, cost_class="deterministic")
+    @a2a.tool(description="Validate OpenAPI, JSON Schema, and webhook contracts with deterministic fixtures", input_schema=_tool_input_schema(ValidateContractRequest), timeout_seconds=120, idempotent=True, max_retries=0, cost_class="deterministic")
     async def validate_contract(self, ctx: RunContext[NoAuth], request: ValidateContractRequest) -> Any:
         dry_run = _effective_dry_run(self, request.dry_run)
         audit = [_audit("contract_validation_started", request.integration_id, {"contracts": len(request.contracts), "dry_run": dry_run})]