C4C Private: host the regulations privately in your tech stack
The same regulation library behind the C4C MCP, running inside your own network or AWS account. Your AI tools and agents read the regulator’s exact words from your own server. Nothing about your work reaches us, and rule updates arrive through your own gates.
Comparing options? Build with C4C sets C4C Private beside the MCP server and the API, with a copy-paste start for each.
A library, not an agent
Most AI tools raise security questions because they act: they call out, write data, or read your files. C4C Private does none of that. At its core it is the regulators’ text, formatted so AI can read it efficiently, with a small lookup server in front. In your environment it:
- Only reads. It cannot write to your systems, take actions or change anything.
- Never sees your documents. Your AI asks it for a topic or a citation; your files stay in your AI tool.
- Has no outside connections. Questions, answers and usage never leave your network, and the server never needs to contact us.
- Cannot be quietly altered. Every release is signed. The server checks the signature before installing anything and refuses what does not verify.
One honest boundary: the risk that remains sits in the AI tool you connect, not in C4C. A cloud assistant (ChatGPT, a Claude connector, Copilot Studio) reaches your server from its vendor’s cloud. For nothing to leave your network, use an in-network agent or model, or add C4C Guardrails.
Machine-readable, so your AI can actually read the rule
Most agency guides are too big for an AI to read whole. In our measurement of all 11,134 current sections, 43% of mortgage rules sit in documents larger than an AI’s context window. C4C hands your AI the one section it needs, about 200 tokens on average, with its citation, version and effective date.
| Source document | Approximate size | One C4C section (median) |
|---|---|---|
| Freddie Mac Seller/Servicer Guide | 1.9 million tokens | about 860 tokens |
| FHA Handbook 4000.1 | 1 million tokens | about 330 tokens |
| Fannie Mae Selling Guide | 650,000 tokens | about 650 tokens |
| Fannie Mae Servicing Guide | 410,000 tokens | about 200 tokens |
Token counts are estimates (characters divided by four), measured against the official downloadable documents. How we measured →
Updates through your own gates
You choose how rule updates arrive. Each release is signed, so it is verified however it travels.
- Your own mirror (no contact with us). Your IT fetches each release at your gate, scans or approves it, and serves it from an internal server or an S3 bucket in your AWS account. Your C4C Private servers update from there, with no license key and no connection to us.
- Direct. The server fetches signed releases from us over HTTPS, sending only your license key.
- Offline. Load the signed release files by hand.
If updates stop, the server keeps answering and marks the library stale after 14 days, so nobody mistakes an old rule for a current one.
Free to download, paid to stay current
The regulations themselves are public, and we don’t charge for them. Downloading the library is free, and any library you download is yours to keep using for research and reference. What you pay for is every release as it ships, and the right to make work product from it: memos, policies and procedures, QC findings, reports and client deliverables.
| Plan | What you get | Price |
|---|---|---|
| Free | The free edition of the library, refreshed a few times a year, for research and reference. Download it again to get the newest free edition. | $0 |
| Internal updates | Every release as it ships, and the right to make work product from it for your own business. | $399 a month |
| Client updates | Every release as it ships, and the right to make work product for your clients and serve them with it: consultants, subservicers, QC firms and software vendors. | $1 to $50 per client a month, depending on volume and how much of the library you use |
Paid plans work the same whichever way updates arrive: your own mirror, direct, or offline. When a paid
term ends, your key goes back to the free edition; releases you downloaded during the term, and the
work product you made, stay yours.
Subscribe to paid updates for commercial use 
· Ask about a client plan.
Already have a free key? The surest way to upgrade is from your C4C Private account: sign in with the email on your key and press Upgrade, then pay with any email or card. Or subscribe above with the same email you used for your key. Either way your key switches to every release on its own, with no new key and no reinstall: your server picks up the next release on its next update check. Your account is also where you get a new key or download the current library for an offline install.
Install on AWS in about 15 minutes
If you already run on AWS, a one-click installer (an AWS CloudFormation template) sets up everything in your own account: the server, a private load balancer, an access token nobody has to type, and logging. It runs on your AWS bill, roughly $35 a month.
- Get a free license key (1 minute): sign up with a work email and copy the key from the confirmation.
- Subscribe on AWS Marketplace (1 minute): open the C4C listing and choose Continue to Subscribe. It is free.
- Run the installer (about 10 minutes, mostly waiting): open the one-click installer, pick your VPC and two private subnets, enter who may reach it (for example your VPN range), paste your license key and create the stack.
- Copy two outputs: the server address, and a command that prints your access token.
- Connect your AI (1 minute): point Claude Code or your Amazon Bedrock agent at the address with the token, then ask a guideline question. The answer comes back with the regulator’s exact words and citation.
No outside internet access is needed. Point the server at your own update mirror (a second template sets one up in an S3 bucket in your account) and it talks only to AWS services in your own account; or let it fetch signed releases from us directly if you prefer. Step-by-step setups for Claude Code, Bedrock AgentCore and other tools, a built-in install check, an optional audit log, and a security review pack for your vendor-risk team are on GitHub.
Get C4C Private
- Docker, anywhere. Build from the public source and install guide on GitHub. Needs Docker, 2 GB of memory and about 5 GB of disk.
- AWS Marketplace. A free container listing for Amazon ECS and EKS, including the S3 mirror setup.
- Microsoft Marketplace. A free listing that deploys to Azure Container Apps in your own subscription.
- Free license key. Sign up with a work email; it is used only to fetch releases, at your gate or on the server. For every release as it ships, add a paid update plan.
The code is public under the Elastic License 2.0. The regulatory library is free to download for research and reference use under the C4C Library License, which also covers paid update plans and client use. Research only, not legal advice.
C4C Sandbox: C4C Private with guardrails, set up and supported
The C4C Sandbox is your own environment where AI does compliance work with mortgage guardrails on:
- C4C Private in your network or AWS account, updated through your gates
- C4C Guardrails: decision records while staff work, and the C4C Monitor checking your AI records after the fact
- C4C Playbooks, including Fannie Mae AI governance (Supplement Section 4)
- Setup, support and an update commitment