What you may do
Helmet Duck's source is visible so that you can inspect every hook before it runs on your machine. You may read it, run it, and evaluate it for your own use. The current version is free and complete for personal use.
What you may not do
Copyright © 2026 Carlos Garita. All rights reserved. You may not copy, modify, redistribute, sublicense, sell or offer as a service the software or any part of it without written permission. A paid licence, when offered, grants use on the number of machines stated at purchase and nothing more. In these terms, "the author" means the copyright holder named here.
Risks, warranty and liability
Every known risk of running Helmet Duck, its mitigation, and what you accept are listed on the risks and mitigations page, which is part of these terms. Installing or using Helmet Duck means you have read that page and accept every risk on it; the software refuses nothing until you record that acceptance with duck accept.
Helmet Duck is provided as is, without warranty of any kind, express or implied, including fitness for a particular purpose and non-infringement. To the fullest extent permitted by applicable law, the author is not liable for any loss, damage, cost or claim arising from Helmet Duck, from its refusals or its failures to refuse, or from any action of an agent, whether that action was refused, allowed, influenced or missed by Helmet Duck. Where the law does not permit an exclusion, liability is limited to the amount you paid for Helmet Duck in the twelve months before the claim, which for the free tier is nothing.
A modified copy is not Helmet Duck. The author is not liable for any copy anyone has modified, for any copy obtained other than from the marketplace at github.com/garitac/helmet-duck and the repositories it names, or for any installation made by a person who did not own the system or lacked the authority to install software on it. Whoever modifies, redistributes, or installs Helmet Duck on a system they do not own is solely responsible for the consequences and for any claim by that system's owner or by anyone affected, and agrees to hold the author harmless from such claims.
Purchases, refunds and invoices
Paid tiers are sold through a merchant of record named at checkout, which is the legal seller of that purchase; its refund terms apply and are shown before you pay. Team engagements are invoiced directly in Japanese yen. Sponsorships through GitHub Sponsors are gifts and are not purchases of anything.
Law
These terms are governed by the laws of Japan, where the author is based. Mandatory consumer protections of your own country apply regardless. A purchase is made from the merchant of record named at checkout, which is the legal seller of that purchase and carries the seller's obligations for it.