License

This repository contains two classes of material under two licenses.

Specification text: CC BY 4.0#

The specification documents (SPEC.md, everything under spec/, and the repository's prose documentation) are

and are licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0). You are free to share and adapt this material for any purpose, including commercially, provided you give appropriate credit.

Everything else in this repository not listed under the Apache-2.0 class below is covered by this CC BY 4.0 class, including index.html and the recorded experiment artifacts under proof/ (transcripts, report cards, rendered pages), which are factual records published with the text.

Full license text: https://creativecommons.org/licenses/by/4.0/legalcode

Machine-readable artifacts and tooling: Apache-2.0#

The contents of schemas/ and conformance/, and the runnable tooling elsewhere in this repository (guides/check-guides.mjs, the proof kit scripts proof/runner.mjs, proof/grader.mjs, proof/render-transcript.mjs, and the workflows under .github/workflows/), are

Licensed under the Apache License, Version 2.0 (the "License"); you may not use these files except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

The full Apache-2.0 license text is included in this repository as LICENSE-APACHE.

This split exists so that implementers can embed the schemas, test vectors, and tooling directly in their software under a standard code license, while the specification text carries the attribution norm appropriate to a published standard. It also matches the MCP extensions ecosystem's convention of Apache-2.0 for extension artifacts.