Owner-approved 2026-10-04; no counsel review.

The text of the CARL Standard v1.0 specification is licensed under the Creative Commons Attribution-NoDerivatives 4.0 International License (CC BY-ND 4.0). The licensor is Wentzel Investments LLC (Wentzel.ai). The grant covers the v1.0 specification text published at /spec/v1.0 and in the /docs/spec/v1.0/ pages, except the criteria catalog.

Everything else is proprietary to Wentzel.ai — all rights reserved. That covers the reference implementations and tooling (@wentzel/carl-engine, @wentzel/carl-cli), the criteria catalog, the reference prompts, working drafts of future versions (such as v1.1), and this docs site's source code and its other prose. No open-source license grant — Apache or otherwise — is in effect for any of it, and no permission is granted to copy, redistribute, modify, or create derivative works from that material without Wentzel.ai's prior written consent.

Current status

If you would like to license, redistribute, or build on any material the CC BY-ND 4.0 grant does not cover, email hello@wentzel.ai to discuss terms.

What CC BY-ND 4.0 lets you do with the spec text

• Share. You may copy and redistribute the unmodified v1.0 spec text in any medium or format, for any purpose, including commercially.
• Attribution. You must give appropriate credit, provide a link to the license, and indicate if changes were made, as the license requires. A suitable credit line is: "CARL Standard v1.0 by Wentzel.ai (Wentzel Investments LLC), licensed under CC BY-ND 4.0 — https://carl.wentzel.ai/spec/v1.0".
• NoDerivatives. If you remix, transform, or build upon the spec text, you may not distribute the modified material.
• No additional restrictions. You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.

The legal code of the license governs; the bullets above are a plain-English summary of it.

Self-attesting your own repository against the CARL Standard's published levels and criteria (i.e., describing your codebase's readiness using CARL's vocabulary) is a description of your own repository and needs no license. Reproducing the criteria catalog, the reference prompts, or CARL code is not licensed.

Historical context — earlier licensing plans

Neither the Apache 2.0 grant nor a CC BY 4.0 grant exists today. Treat CARL code, prompts, the criteria catalog, and every other non-spec asset as all rights reserved unless and until this page is updated to say otherwise.

The patent non-assertion covenant

The covenant that earlier drafts paired with the CC BY 4.0 plan promised not to assert patent claims against conformant implementations built by third parties. It is not in effect. The CC BY-ND 4.0 grant for the spec text does not reinstate it: Creative Commons licenses expressly do not license patent rights, so the spec license is a copyright license only. Any future patent covenant for the standard would be published on this page.

What this means in practice

• You may read the spec and docs published at carl.wentzel.ai for your own reference.
• You may copy and share the unmodified v1.0 spec text under CC BY-ND 4.0, with attribution.
• You may not distribute modified versions of the spec text, and you may not copy, redistribute, modify, or build derivative tooling from CARL code, the reference prompts, or the criteria catalog without a separate written agreement with Wentzel.ai.

Third-party components

This docs site and the broader monorepo depend on upstream open-source software. Licenses of those components are listed in each package's package.json; an aggregated SBOM is milestone-tagged (M10) work. Those third-party licenses are unaffected by this page — they govern the dependency, not CARL's own code or spec.

Related

• Trademark — how the CARL name and marks may be used.
• Governance of the Standard — how changes to the standard (including license status) are reviewed and decided.
• Conformance claims — how published claims work today, independent of the code/spec license status.
• Terms of Use — the terms for using this site.