MCP Gateway · Self-Hosted · .NETGive AI Agents the Keys
to Your .NET Stack
Ithil is a self-hosted MCP gateway that exposes your .NET services as tools AI agents can call — without rewrites, without compromise.
How It Works
One attribute. One gateway. Full control.
Ithil sits in front of your existing .NET services and turns them into governed, observable MCP tools — without touching your business logic.
Annotate
Add a single attribute to any C# controller method. A Roslyn Source Generator builds the MCP-compliant schema at compile time — zero runtime reflection. Using minimal APIs? Chain .WithAgentTool() onto the route instead.
[AgentTool("Returns stock levels for a SKU",
Category = "Inventory",
RequiredScopes = ["inventory.read"],
AllowWrite = false,
MaxResponseTokens = 500)]
public async Task<IActionResult> GetInventory(
int productId, string warehouseId)Deploy
Run the Ithil gateway in front of your existing services. No rewrites. Ithil handles identity, budgets, caching, and tracing in the request path.
Connect
Point any MCP-compatible agent at your gateway URL. Claude, GPT, AutoGen — your .NET services are now AI-callable tools, governed and observable from day one.
What You Get
Built for production AI workloads
Compile-Time Schema Generation
“Agents hallucinate with messy REST APIs”
Roslyn auto-generates MCP-compliant schemas from your C# controllers at build time. Minimal-API routes opt in with one .WithAgentTool() call.
Per-Agent Token Budgets
“Agents loop and burn thousands in LLM costs”
Redis-backed daily token ledger enforces per-agent limits with automatic 429 responses.
Privacy Filter
“PII leaking to external LLMs”
Configurable scrubber strips emails, SSNs, credit cards, and custom patterns before data leaves your network.
Semantic Cache
“Redundant LLM calls cost thousands per month”
Redis vector search deduplicates intent-equivalent requests — not just identical ones.
Real-Time Trace Dashboard
“No visibility into what agents are actually doing”
SignalR-powered live feed shows every tool call, token spend, and outcome as it happens.
Circuit Breaker & Auth
“Agents calling destructive endpoints unchecked”
Polly circuit breaker + JWT/API key identity verification + per-tool scope enforcement.
Pricing
Simple. No surprises.
Free if you're not making money with it. Flat rate if you are.
Non-Commercial
For personal projects, open-source work, research, and internal evaluation.
- ✓Full feature set — nothing held back
- ✓Self-hosted on your infrastructure
- ✓Personal & open-source projects
- ✓Research and internal evaluation
- ✓License key delivered via email
Licensed under BSL 1.1. Converts to Apache 2.0 in 2036.
Commercial
For production use in any commercial product or service.
- ✓Full feature set — nothing held back
- ✓Self-hosted on your infrastructure
- ✓Unlimited production deployments
- ✓License key delivered via email
- ✓Email support
One license covers your whole team.
FAQ
Questions worth answering
Is this actually open source?✕
Ithil is source-available under the Business Source License 1.1. The full source code is public and free for non-commercial use — personal projects, open-source work, research, and internal evaluation. Commercial production use requires a $149/mo license. The license converts to Apache 2.0 on April 17, 2036.
What counts as "commercial use"?✕
If Ithil is running in a product or service that generates revenue — directly or indirectly — that's commercial use. If you're hacking on a side project, contributing to open source, or evaluating it internally before a purchase decision, you're covered under the free tier.
Do I have to rewrite my existing .NET services?✕
No. Ithil sits in front of your existing services as a gateway. You add the [AgentTool] attribute to the controller methods you want to expose (or chain .WithAgentTool() onto minimal-API routes), deploy the gateway, and you're done. Your business logic doesn't change.
Which AI agents and models does it support?✕
Any client that speaks Model Context Protocol — Claude, GPT-4, AutoGen, Cursor, and any MCP-compatible agent. Ithil exposes a standard JSON-RPC 2.0 interface, so if the agent supports MCP, it works.
Does my data leave my network?✕
Never. Ithil is entirely self-hosted. Your services, your data, your infrastructure. The privacy filter scrubs PII from responses before they ever reach an LLM — that's enforced at the gateway level, not opt-in.
What do I need to run it?✕
.NET 9 or later, Redis (for token budgets and semantic cache), and Docker for deployment. A docker-compose setup ships with the project to get you running in minutes.
How do I get my license key?✕
Everyone gets a key — free or paid. Non-commercial users register with just an email address and receive a signed license key immediately. Commercial users complete a checkout and receive their key the same way. Drop it into your appsettings.json and you're done. No account portal, no dashboard to log into.
What if I need something beyond the standard license?✕
Get in touch at robert@crosslandcreative.com. Enterprise agreements, custom terms, volume pricing, and support SLAs are all available.
Get Started Free
Get your free license key
Non-commercial use is free. Enter your email and your signed license key arrives in your inbox — no account, no credit card.
We will never sell or share your email. Ever.
Building something commercial? See commercial licensing →