1. What Zevruna does
Zevruna performs the standard Model Context Protocol handshake against servers you register (initialize, tools/list, resources/list, prompts/list) on a schedule, records the advertised contract, and reports when it changes. It compares those contracts against consumer manifests you generate, and can fail your CI when your code and a server's contract disagree.
The monitor never invokes a tool with real arguments and never sits in your agent's execution path. It is also the whole product: an SDK is never required in your production code, and everything above works without one.
The SDKs are optional and do run inside your process, because reconstructing an execution is the only way to show you one. They report execution metadata, what ran, in what order, how long it took, and whether it failed. They never read tool arguments or return values, with one exception you control: the text an MCP server returns alongside isError, which is off by default. You can also send us OpenTelemetry directly instead of installing anything, in which case we store the spans you choose to export. See Data collected for the field-by-field list.
2. Your account
You need an account to monitor private servers. You are responsible for keeping your project token and any API keys you create secret, and for activity carried out with them. Tell us promptly if you believe one has been exposed. A project token can be rotated from Settings, and an API key revoked there individually.
Accounts are self-serve and free to create. We may limit or decline an account at our discretion, for example where use would breach these terms.
3. Servers you register
By registering a server you confirm you are entitled to connect to it, and that doing so does not breach any agreement you have with its operator. Zevruna identifies itself on every request with the user agent zevruna-monitor/1.0 and polls at the interval your plan provides.
We refuse endpoints that resolve to private, loopback, link-local, or cloud metadata addresses. Do not attempt to use Zevruna to reach systems you could not otherwise reach, to scan networks, or to generate load against a third party. We may suspend monitoring of any endpoint that appears to be used this way, or that asks us to stop.
4. The public monitor and advisories
Zevruna monitors publicly reachable MCP servers regardless of whether anyone has signed up, and publishes breaking contract changes as advisories with a hosted changelog per server.
These record schemas the servers themselves publish to every client that connects. Advisories are factual observations of those published schemas: what changed, and when we observed it. They are not a judgement about the server, its operator, or its quality.
If you operate a monitored server and want a correction, the polling interval changed, or the server removed from the public monitor, write to us and we will act promptly.
5. Plans, billing, and cancellation
Paid plans are billed in advance, monthly or annually, through Stripe. Annual billing is charged as ten months. Your plan sets how many agent runs you may report each month, how long that run telemetry is kept, how many agents may report, how many private servers you may monitor, how often they are polled, and how many consumer manifests you may keep. Every one of those is enforced by the service rather than stated on the pricing page alone.
Two of those limits behave in ways worth stating plainly. Run telemetry beyond your retention window is deleted by a daily sweep, three days on Free, thirty on Pro, ninety on Scale, while contract snapshots and incidents are kept until you delete the project. And when you exceed the monthly run allowance we stop recording new runs and say so; we never make your SDK throw, because turning a billing state into a customer outage is the failure this product exists to argue against.
You can cancel at any time from Settings, and upgrade, downgrade or change your card from the billing portal. Cancelling stops future charges and takes effect at the end of the period you have paid for. We do not refund partial periods, but if something went wrong on our side, write to us and we will make it right.
If a payment fails, your plan falls back to Free rather than being cut off, so monitoring continues at Free limits while you sort the payment out.
Prices may change. We will give at least 30 days' notice before a change affects an existing subscription.
6. What we do not promise
Zevruna is a monitoring product, and monitoring is best-effort by nature. We do not guarantee that every contract change will be detected, or detected within any particular time. Detection depends on your polling interval, on the server being reachable when we poll, and on the change being visible in what the server advertises.
Zevruna is not a security product, does not test whether a server behaves correctly, and cannot detect a change a server does not advertise. It is explicitly not a substitute for testing, error monitoring, or your own judgement about the dependencies you take.
The service is provided as is and as available, without warranties of any kind to the fullest extent the law allows.
7. Liability
To the extent the law allows, neither party is liable for indirect, incidental, special, or consequential damages, or for lost profits or lost data, arising from these terms or your use of the service.
Our total liability for any claim is limited to the amount you paid us in the twelve months before the claim arose. If you are on a free plan, that amount is zero, which is the honest consequence of a service costing nothing.
8. Intellectual property
The diff engine, the canonicalizer, differ, classifier, impact resolver, and manifest checker, is open source under the MIT licence. You may read, use, fork, and build on it. It is published deliberately, so anyone can verify exactly what we mean by a breaking change.
Your data stays yours. Snapshots, manifests, incidents, and check history belong to you, and you can export them through the API at any time. We claim no ownership of them and do not use them to train models.
The Zevruna name, mark, and site content remain ours.
9. Suspension and termination
You may close your account at any time. We may suspend or close an account that breaches these terms, that is used to attack or overload third-party systems, or where we are required to by law.
If we close your account other than for breach, we will give you reasonable notice and a chance to export your data.
10. Changes
We may update these terms. For material changes affecting a paid plan we will give at least 30 days' notice by email to the address on the account. Continuing to use the service after a change takes effect means you accept it.
11. Governing law
These terms are governed by the laws of the State of Delaware, United States, without regard to conflict-of-law rules. Nothing here removes rights you have under mandatory consumer law where you live.
12. Contact
Questions about these terms: legal@zevruna.com.