FastLED Reciprocal License

This repository publishes the canonical text and supporting materials for the proposed FastLED Reciprocal License 1.0. Despite its name, the license is a general-purpose instrument that may be applied to software from any project. It is not limited to the FastLED codebase.

Important

The current text is release candidate 1.0-rc3, identified as LicenseRef-FastLED-Reciprocal-1.0-rc3. It is preliminary legal drafting, is not OSI-approved, and has not completed the attorney gate in LEGAL-REVIEW.md. The identifier without an -rc suffix is reserved for a reviewed release.

License text and software rights are separate

The license does not require a universal "owner." Zachary Vorhies currently maintains the canonical license-text repository and its version history. That text-maintenance role does not make Zach, FastLED, or this repository the owner, separate-permission grantor, or enforcement claimant for software that another project places under the license.

The roles are intentionally separate:

Role	Authority
Canonical text maintainer	Publishes and versions the reusable license text
Adopting rights holder or Contributor	Applies the license and grants rights in its Contributions
Separate-permission grantor	Grants separate written permission only when independently authorized for the relevant software
Enforcement claimant	Enforces only rights or promises for which it has the required ownership, authorization, or standing

Publishing or copying LICENSE does not transfer software copyrights or appoint the text maintainer to enforce an adopter's code.

Design

The license is one self-contained instrument derived from Mozilla Public License 2.0 under MPL Section 10.3. It is a monetization-triggered reciprocal open-source license that is not OSI-approved. It preserves a file-level Covered Software boundary: independent files in a Larger Work may remain proprietary under Section 11.2.

The license's mission is to return privately maintained improvements to the official source project when those improvements materially enable non-exempt monetization. Before the first Monetization Event for each modified version, the modifier must publish the Compliance Source for the covered portion through the official upstream project as a public pull request, public fork, or complete reproducible patch. Genuine educational, scholarly, media, and unrestricted-donation activities are exempt under the exact boundaries in Section 11.1.

An adopting project identifies its Upstream Repository and Official Reporting Location in or with the Exhibit A notice. Those project-specific designations do not alter the canonical license text and do not make either repository's maintainer a rights holder.

Separate written permission is optional and project-specific. Section 11.3(g) recognizes only written authorization from all necessary software rightsholders or their authorized licensing entity. No one is required to offer that permission, and the canonical license repository cannot grant exceptions for third-party software merely because it publishes this text.

GPL-family compatibility is enabled by default through the MPL-style Secondary License mechanism. If a recipient validly elects GPL 2.0 or later, LGPL 2.1 or later, or AGPL 3.0 or later, the elected license controls where its terms conflict with this license. The FastLED license and applicable provenance notices travel with the covered code to the extent the elected license permits. An adopter may instead attach Exhibit B to opt out of Secondary Licenses.

Each canonical version is immutable. Verbatim copying is permitted, but the license text may not be altered and still presented as the FastLED Reciprocal License. An adopter selects either the pinned version only or that version or later; omission defaults to the pinned version only. A software rightsholder who wants different terms publishes a separately licensed release or fork without changing grants already made for earlier releases.

The generic LICENSE-AI-AGENT-INSTRUCTIONS.md notice is part of the license and must be included by every adopting project under Section 11.7(a). The inclusion obligation binds the human or legal entity exercising the copyright license. The notice does not pretend that an automated agent is a contracting party or independently subject to damages.

Contents

• LICENSE — current reusable release-candidate text.
• MPL-2.0.txt — unmodified MPL 2.0 source retained for provenance; it is not incorporated into the license.
• PROVENANCE.md — derivation and immutable-version records.
• LEGAL-REVIEW.md — attorney-review gate and unresolved drafting decisions.
• paralegal-research/ — license-agnostic research corpus for attorney review.
• NOTICE-TEMPLATE.txt — optional source notice for adopters.
• header-policy.toml, header-policy.schema.json, and tools/license_headers.py — optional example tooling for repositories that want automated source-file notices.
• LICENSE-AI-AGENT-INSTRUCTIONS.md — required generic AI Coding Agent Notice, also reproduced as Exhibit C and incorporated by Section 11.7.
• ai-policy.toml — machine-readable summary of the required notice and its legal boundary.
• LICENSE-MIT-LEGACY and NOTICE-TEMPLATE-MIT-LEGACY.txt — FastLED migration examples, not requirements imposed on other adopters.

Applying the license to a project

1. Obtain project-specific legal review and confirm that the people applying the license have sufficient rights in the software they are offering.
2. Copy an immutable reviewed license release into the adopting repository.
3. Attach the Exhibit A notice or the corresponding SPDX identifier to the Covered Software. Record whether the adoption is this version only or this version or later, plus the project's Upstream Repository and Official Reporting Location.
4. Include LICENSE-AI-AGENT-INSTRUCTIONS.md as the complete generic Exhibit C notice. It is required for every adopting project, whether or not that project expects AI-assisted development.
5. Preserve third-party notices and licenses. Do not overwrite separately licensed or generated material with a project-wide header.
6. If the project offers separate written permissions, publish its own contact and authorization process separately from the canonical license text.

No change to the FastLED software repository is necessary to draft, publish, study, or use this license text. FastLED remains under its existing license unless and until the FastLED project separately adopts a reviewed version.

Optional header tool

Repositories that choose to use the example tool need only uv:

uv run tools/license_headers.py inventory --profile release
uv run tools/license_headers.py check --profile release
uv run tools/license_headers.py update --profile release
uv run tools/license_headers.py apply --profile release

The included policy is a starting point, not part of the legal instrument. Each adopter must replace its roots, exclusions, and provenance while retaining the required generic AI Coding Agent Notice. The tool refuses to stamp the final non--rc identifier until LEGAL-REVIEW.md records approval.

Reviewed releases should be immutable tags with a recorded content digest. Adopters should copy a selected release rather than follow mutable legal text during a build or release.

References

• Mozilla Public License 2.0
• SPDX custom LicenseRef syntax
• Preliminary research and attorney-review issues are tracked in this repository's GitHub issue list.