Evaluate MCP gateway security with concrete allow, deny and audit tests, data handling checks and deployment requirements for procurement.
An MCP gateway purchase should establish which tools an application may use, what gets denied and what evidence remains. Evaluate Sluis against a written acceptance plan that separates available policy controls from integration requirements your team still needs to validate.
Define the boundary you are buying
Sluis provides a managed EU-first gateway with multiple providers, OpenAI and Anthropic compatible APIs, and policy controls for both models and MCP tools. API compatibility is not proof that every MCP server, transport or authentication scheme is supported. List the exact client, server and identity requirements before choosing a deployment.
Illustrative scenario: a finance assistant needs to read invoices but must not export the full ledger. Your proposed MCP server exposes fictional tools named invoices.read and invoices.export. These names describe a procurement test, not shipped Sluis integrations. Decide where user authorization, workload identification and the server’s own permissions must be enforced.
- Inventory the models, MCP servers and tools each workload needs.
- Document authentication and server-identity requirements for validation.
- Separate gateway policy from permissions enforced by the tool backend.
Test allowed and denied actions separately
Illustrative acceptance test: configure the invoice-review workload for an approved model and invoices.read on the designated test server. A synthetic invoice read should pass; invoices.export and a model outside the approved set should be denied. Repeat from a different workload to check that access does not carry over unintentionally.
Exercise allow and deny modes separately, then test a second server presenting the same tool name. Require a demonstration of how policy identifies the intended server rather than assuming name matching is sufficient. Tool-level permission does not by itself establish argument validation, protection against prompt injection or authorization inside the downstream system.
- Record expected and observed outcomes for each allow and deny case.
- Test a disallowed model, a different workload and a duplicate tool name.
- Validate argument checks and downstream authorization as separate requirements.
Inspect the audit trail and data handling
Sluis provides a hash-chained audit trail. For each allowed and denied test, request evidence showing which workload, model, tool and policy decision can actually be reconstructed. In a controlled copy of the records, alter or remove an entry and ask how verification detects it. Hash chaining is not the same as immutable storage or complete event coverage.
Data protection defaults to reversible tokenization; mask, block and allow_log are distinct modes. Detection is not perfect, and existing web search results and model output are not newly tokenized. Security scanning is optional. Content retention is on by default until erased or configured otherwise, while metadata is retained. Test the actual MCP data path rather than assuming every tool payload receives identical treatment.
- Collect evidence for successful calls, denied calls and verification failures.
- Test synthetic sensitive input and inspect what reaches the tool and audit trail.
- Agree content retention, erasure, metadata access and optional scanning settings.
Make deployment and evidence contractual
Choose between the managed service and Edge according to your operating requirements. Edge runs the full product on your own Kubernetes or Docker, including air-gapped deployments with local models. Your organization operates backups and manages the licence. Validate available models and tools under the chosen network and policy restrictions rather than assuming every combination works.
EU residency, EU ownership and exposure to US law are different procurement questions. Use the existing sovereignty guide for deeper due diligence, and review the published ISO 27001 material without treating it as a legal guarantee. Sluis pricing is usage-based; use the pricing page and agree acceptance evidence, unresolved integration requirements and operational responsibilities before signing.
- Assign ownership for deployment, backups, licences and incident handling.
- Verify the selected providers and model availability under your policy.
- Attach test results and unresolved requirements to procurement approval.
Questions before you decide
Does API compatibility guarantee that our MCP server will work?
No. OpenAI and Anthropic API compatibility does not establish MCP transport, protocol-version or authentication compatibility. Ask Sluis to validate your actual client and server combination, including identity handling, before treating the integration as supported.
Does a hash-chained audit trail guarantee compliance?
No. It supports integrity verification, but you still need to validate event coverage, access controls, retention and verification procedures. Legal suitability depends on your processing and obligations, not on a single audit feature.
Can every model be used under an EU-only policy?
Do not assume so. Model availability depends on the selected provider, deployment and policy. Verify the complete processing route; EU hosting alone does not settle ownership or foreign legal exposure.