Security gateway for AI-agent actions

Control what AI agents can do.

Castling enforces policies on agent tool calls and applies configured PII masking to selected personal data in traffic routed through its gateway—outside the agent’s own decision logic.

AI agent
Castling gateway
Connected MCP tools
Policy enforcementPII masking

Context changes the question

An allowed action isn't always a safe action.

Sending a message may be routine. Sending it to a new external destination, with an unusual number of recipients, after a large customer-data read raises different questions. The action, its parameters and the available context matter together.

Customer data read

Step 1

Archive created

Step 2

External message proposed

Step 3

Illustrative risk scenario, not a live product result. Sequence alone does not prove that the message contains the customer data.

Available controls

Start with controls you can test today.

Start with a rule your workflow needs: an action to restrict, or selected personal data to mask.

Restrict a tool action

Define which tool actions are allowed on the connected workflow. Test permitted work alongside actions the policy should block.

RuleAllow reading records. Deny deletion.
ExampleRead a recordAllowed
ExampleDelete a recordBlocked by policy

Mask personal data

Mask selected personal data on the connected traffic path. Check that the agent can still complete the task with the masked content.

RuleMask email addresses in the selected payload.
BeforeContact: alex@example.com
AfterContact: [EMAIL]

Illustrative examples. The integration path and supported rules are confirmed for each pilot.

How it works

Put controls on the path you need to govern.

Castling evaluates tool calls before forwarding them to connected MCP servers. Policy enforcement and configured PII masking apply to traffic routed through the gateway, outside the agent’s own decision logic.

Agent
Castling Gateway
MCP Tools
Policy enforcement
Configured PII masking

Controls apply to traffic routed through Castling. Other access paths need their own controls.

Deploy in your environment. We’ll confirm deployment needs and integration fit for the selected workflow.

  1. 1

    Choose the path.

    Map one working agent workflow and the tools or data involved.

  2. 2

    Define the controls.

    Choose the actions to restrict or the selected personal data to mask.

  3. 3

    Test the result.

    Check the selected controls and successful task completion.

Using a different setup? Describe your stack and we’ll check integration fit.

Castling's approach

Beyond individual tool calls.

Castling’s approach looks beyond the tool name to the action’s arguments, relevant behavior and the execution context available on the connected path.

01

Inspect the action.

Consider the tool, arguments, destination and magnitude.

02

Consider available context.

Look at relevant prior actions and behavioral patterns without treating sequence alone as proof.

03

Define the response.

Agree which supported controls, checks or review steps make sense for the workflow.

Unusual behavior is a signal to investigate, not proof of harm.

Pilot program

Bring one workflow. Test it with us.

Bring a working agent workflow. Together, we’ll choose the relevant controls and risk questions, test representative tasks and review the results. Internal tools, customer-facing products and working prototypes are welcome.

A good starting point

  • Your agent already performs a useful task with tools or business data.
  • You want to explore which actions or selected personal data need controls.
  • Someone on your team can help connect the workflow and review the results.

What we’ll do together

  • Map the connected execution path and the workflow you want to test.
  • Choose the relevant controls and risk questions.
  • Configure supported policy enforcement or PII masking where it fits the scenario.
  • Run representative tasks and review the results and limitations.

What you get

An agreed pilot scope, representative test results and documented limitations.

Pilot scope, timing and commercial terms are agreed together.

Discuss a pilot

FAQ

Before we start

What can we test in a pilot?

Together, we’ll choose the controls and scenarios that matter for your workflow. This may include policy enforcement, configured PII masking for selected personal data, and examination of action arguments, behavior or available context where the integration supports it.

Does our agent need to be in production?

No. A working prototype or staging workflow can be a useful starting point. We need representative tasks and someone who can help us test them.

Will Castling work with our stack?

The current integration model is an MCP gateway. Tell us about your agent, tools and deployment needs so we can check compatibility and identify what the pilot can cover.

We already use permissions, a sandbox or checks in code. Why add Castling?

Existing permissions, sandboxing and checks in code remain essential. Castling adds a policy enforcement point for connected tool calls, so teams can apply and test controls outside the agent’s own logic. A pilot helps determine whether that provides useful additional protection for your workflow.

How long does a pilot take, and what does it cost?

Scope, timing and commercial terms depend on the workflow and integration. We agree them before the pilot begins.

Discuss a pilot

What does your agent do?

Tell us which tools or systems it uses. You don’t need to have a security use case defined yet.

Please use a high-level description. Don’t include credentials, customer records or other sensitive data.

Where we can contact you about the pilot.

Tell us which tools or systems it uses. If you already know what you want to control, include it.

We’ll review the workflow and contact you to discuss fit and next steps.