diff --git a/.claude/CLAUDE.md b/.claude/CLAUDE.md
index a7657d8..9107798 100644
--- a/.claude/CLAUDE.md
+++ b/.claude/CLAUDE.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 ## Machine-Readable Artefacts
diff --git a/.claude/PROJECT.md b/.claude/PROJECT.md
index 544fa0d..c883570 100644
--- a/.claude/PROJECT.md
+++ b/.claude/PROJECT.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # BetLang - Claude Code Instructions
diff --git a/.github/workflows/spark-theatre-gate.yml b/.github/workflows/spark-theatre-gate.yml
index 6e68a32..bce3480 100644
--- a/.github/workflows/spark-theatre-gate.yml
+++ b/.github/workflows/spark-theatre-gate.yml
@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: PMPL-1.0
+# SPDX-License-Identifier: MPL-2.0
 # Estate SPARK Theatre Gate — thin caller of the reusable workflow in
 # hyperpolymath/standards (#135 / #141). Pinned by commit SHA per the
 # estate action-pinning policy. Regenerate the pin only when the reusable
diff --git a/.machine_readable/6a2/README.adoc b/.machine_readable/6a2/README.adoc
index ac38c25..c851cfb 100644
--- a/.machine_readable/6a2/README.adoc
+++ b/.machine_readable/6a2/README.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 # A2ML 6a2 Directory
 
diff --git a/.machine_readable/self-validating/README.adoc b/.machine_readable/self-validating/README.adoc
index ce1825f..c99953c 100644
--- a/.machine_readable/self-validating/README.adoc
+++ b/.machine_readable/self-validating/README.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 = K9 Contractiles
 :toc: left
diff --git a/.machine_readable/svc/README.adoc b/.machine_readable/svc/README.adoc
index 79d05bd..dd9f825 100644
--- a/.machine_readable/svc/README.adoc
+++ b/.machine_readable/svc/README.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 = `.machine_readable/svc/` — Service components for betlang
 :toc:
diff --git a/ABI-FFI-README.md b/ABI-FFI-README.md
index af300f5..ada05ff 100644
--- a/ABI-FFI-README.md
+++ b/ABI-FFI-README.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 {{~ Aditionally delete this line and fill out the template below ~}}
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 006073a..af2c613 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Changelog
diff --git a/CLAUDE.md b/CLAUDE.md
index 0ac3086..cdfeec7 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # CLAUDE.md
diff --git a/CODE_OF_CONDUCT.md b/CODE_OF_CONDUCT.md
index 3db64ac..d1db27f 100644
--- a/CODE_OF_CONDUCT.md
+++ b/CODE_OF_CONDUCT.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Contributor Covenant Code of Conduct
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 6a793f4..0ef28ec 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Clone the repository
diff --git a/EXPLAINME.adoc b/EXPLAINME.adoc
index 4667f84..4f34b1a 100644
--- a/EXPLAINME.adoc
+++ b/EXPLAINME.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 // SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath)
 // @taxonomy: explainme
diff --git a/GOVERNANCE.adoc b/GOVERNANCE.adoc
index 8bbf167..e41020d 100644
--- a/GOVERNANCE.adoc
+++ b/GOVERNANCE.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 = Governance Model
 :toc: preamble
diff --git a/LICENSE b/LICENSE
index d0a1fa1..14e2f77 100644
--- a/LICENSE
+++ b/LICENSE
@@ -35,7 +35,7 @@ Mozilla Public License Version 2.0
     means any form of the work other than Source Code Form.
 
 1.7. "Larger Work"
-    means a work that combines Covered Software with other material, in
+    means a work that combines Covered Software with other material, in 
     a separate file or files, that is not Covered Software.
 
 1.8. "License"
@@ -357,7 +357,7 @@ Exhibit A - Source Code Form License Notice
 
   This Source Code Form is subject to the terms of the Mozilla Public
   License, v. 2.0. If a copy of the MPL was not distributed with this
-  file, You can obtain one at https://mozilla.org/MPL/2.0/.
+  file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 If it is not possible or desirable to put the notice in a particular
 file, then You may include the notice in a location (such as a LICENSE
diff --git a/LICENSES/CC-BY-SA-4.0.txt b/LICENSES/CC-BY-SA-4.0.txt
new file mode 100644
index 0000000..835a683
--- /dev/null
+++ b/LICENSES/CC-BY-SA-4.0.txt
@@ -0,0 +1,170 @@
+Creative Commons Attribution-ShareAlike 4.0 International
+
+ Creative Commons Corporation (“Creative Commons”) is not a law firm and does not provide legal services or legal advice. Distribution of Creative Commons public licenses does not create a lawyer-client or other relationship. Creative Commons makes its licenses and related information available on an “as-is” basis. Creative Commons gives no warranties regarding its licenses, any material licensed under their terms and conditions, or any related information. Creative Commons disclaims all liability for damages resulting from their use to the fullest extent possible.
+
+Using Creative Commons Public Licenses
+
+Creative Commons public licenses provide a standard set of terms and conditions that creators and other rights holders may use to share original works of authorship and other material subject to copyright and certain other rights specified in the public license below. The following considerations are for informational purposes only, are not exhaustive, and do not form part of our licenses.
+
+Considerations for licensors: Our public licenses are intended for use by those authorized to give the public permission to use material in ways otherwise restricted by copyright and certain other rights. Our licenses are irrevocable. Licensors should read and understand the terms and conditions of the license they choose before applying it. Licensors should also secure all rights necessary before applying our licenses so that the public can reuse the material as expected. Licensors should clearly mark any material not subject to the license. This includes other CC-licensed material, or material used under an exception or limitation to copyright. More considerations for licensors.
+
+Considerations for the public: By using one of our public licenses, a licensor grants the public permission to use the licensed material under specified terms and conditions. If the licensor’s permission is not necessary for any reason–for example, because of any applicable exception or limitation to copyright–then that use is not regulated by the license. Our licenses grant only permissions under copyright and certain other rights that a licensor has authority to grant. Use of the licensed material may still be restricted for other reasons, including because others have copyright or other rights in the material. A licensor may make special requests, such as asking that all changes be marked or described.
+
+Although not required by our licenses, you are encouraged to respect those requests where reasonable. More considerations for the public.
+
+Creative Commons Attribution-ShareAlike 4.0 International Public License
+
+By exercising the Licensed Rights (defined below), You accept and agree to be bound by the terms and conditions of this Creative Commons Attribution-ShareAlike 4.0 International Public License ("Public License"). To the extent this Public License may be interpreted as a contract, You are granted the Licensed Rights in consideration of Your acceptance of these terms and conditions, and the Licensor grants You such rights in consideration of benefits the Licensor receives from making the Licensed Material available under these terms and conditions.
+
+Section 1 – Definitions.
+
+     a.	Adapted Material means material subject to Copyright and Similar Rights that is derived from or based upon the Licensed Material and in which the Licensed Material is translated, altered, arranged, transformed, or otherwise modified in a manner requiring permission under the Copyright and Similar Rights held by the Licensor. For purposes of this Public License, where the Licensed Material is a musical work, performance, or sound recording, Adapted Material is always produced where the Licensed Material is synched in timed relation with a moving image.
+
+     b.	Adapter's License means the license You apply to Your Copyright and Similar Rights in Your contributions to Adapted Material in accordance with the terms and conditions of this Public License.
+
+     c.	BY-SA Compatible License means a license listed at creativecommons.org/compatiblelicenses, approved by Creative Commons as essentially the equivalent of this Public License.
+
+     d.	Copyright and Similar Rights means copyright and/or similar rights closely related to copyright including, without limitation, performance, broadcast, sound recording, and Sui Generis Database Rights, without regard to how the rights are labeled or categorized. For purposes of this Public License, the rights specified in Section 2(b)(1)-(2) are not Copyright and Similar Rights.
+
+     e.	Effective Technological Measures means those measures that, in the absence of proper authority, may not be circumvented under laws fulfilling obligations under Article 11 of the WIPO Copyright Treaty adopted on December 20, 1996, and/or similar international agreements.
+
+     f.	Exceptions and Limitations means fair use, fair dealing, and/or any other exception or limitation to Copyright and Similar Rights that applies to Your use of the Licensed Material.
+
+     g.	License Elements means the license attributes listed in the name of a Creative Commons Public License. The License Elements of this Public License are Attribution and ShareAlike.
+
+     h.	Licensed Material means the artistic or literary work, database, or other material to which the Licensor applied this Public License.
+
+     i.	Licensed Rights means the rights granted to You subject to the terms and conditions of this Public License, which are limited to all Copyright and Similar Rights that apply to Your use of the Licensed Material and that the Licensor has authority to license.
+
+     j.	Licensor means the individual(s) or entity(ies) granting rights under this Public License.
+
+     k.	Share means to provide material to the public by any means or process that requires permission under the Licensed Rights, such as reproduction, public display, public performance, distribution, dissemination, communication, or importation, and to make material available to the public including in ways that members of the public may access the material from a place and at a time individually chosen by them.
+
+     l.	Sui Generis Database Rights means rights other than copyright resulting from Directive 96/9/EC of the European Parliament and of the Council of 11 March 1996 on the legal protection of databases, as amended and/or succeeded, as well as other essentially equivalent rights anywhere in the world.
+
+     m.	You means the individual or entity exercising the Licensed Rights under this Public License. Your has a corresponding meaning.
+
+Section 2 – Scope.
+
+     a.	License grant.
+
+          1. Subject to the terms and conditions of this Public License, the Licensor hereby grants You a worldwide, royalty-free, non-sublicensable, non-exclusive, irrevocable license to exercise the Licensed Rights in the Licensed Material to:
+
+               A. reproduce and Share the Licensed Material, in whole or in part; and
+
+               B. produce, reproduce, and Share Adapted Material.
+
+          2. Exceptions and Limitations. For the avoidance of doubt, where Exceptions and Limitations apply to Your use, this Public License does not apply, and You do not need to comply with its terms and conditions.
+
+          3. Term. The term of this Public License is specified in Section 6(a).
+
+          4. Media and formats; technical modifications allowed. The Licensor authorizes You to exercise the Licensed Rights in all media and formats whether now known or hereafter created, and to make technical modifications necessary to do so. The Licensor waives and/or agrees not to assert any right or authority to forbid You from making technical modifications necessary to exercise the Licensed Rights, including technical modifications necessary to circumvent Effective Technological Measures. For purposes of this Public License, simply making modifications authorized by this Section 2(a)(4) never produces Adapted Material.
+
+          5. Downstream recipients.
+
+               A. Offer from the Licensor – Licensed Material. Every recipient of the Licensed Material automatically receives an offer from the Licensor to exercise the Licensed Rights under the terms and conditions of this Public License.
+
+               B. Additional offer from the Licensor – Adapted Material. Every recipient of Adapted Material from You automatically receives an offer from the Licensor to exercise the Licensed Rights in the Adapted Material under the conditions of the Adapter’s License You apply.
+
+               C. No downstream restrictions. You may not offer or impose any additional or different terms or conditions on, or apply any Effective Technological Measures to, the Licensed Material if doing so restricts exercise of the Licensed Rights by any recipient of the Licensed Material.
+
+          6. No endorsement. Nothing in this Public License constitutes or may be construed as permission to assert or imply that You are, or that Your use of the Licensed Material is, connected with, or sponsored, endorsed, or granted official status by, the Licensor or others designated to receive attribution as provided in Section 3(a)(1)(A)(i).
+
+     b.	Other rights.
+
+          1. Moral rights, such as the right of integrity, are not licensed under this Public License, nor are publicity, privacy, and/or other similar personality rights; however, to the extent possible, the Licensor waives and/or agrees not to assert any such rights held by the Licensor to the limited extent necessary to allow You to exercise the Licensed Rights, but not otherwise.
+
+          2. Patent and trademark rights are not licensed under this Public License.
+
+          3. To the extent possible, the Licensor waives any right to collect royalties from You for the exercise of the Licensed Rights, whether directly or through a collecting society under any voluntary or waivable statutory or compulsory licensing scheme. In all other cases the Licensor expressly reserves any right to collect such royalties.
+
+Section 3 – License Conditions.
+
+Your exercise of the Licensed Rights is expressly made subject to the following conditions.
+
+     a.	Attribution.
+
+          1. If You Share the Licensed Material (including in modified form), You must:
+
+               A. retain the following if it is supplied by the Licensor with the Licensed Material:
+
+                    i.	identification of the creator(s) of the Licensed Material and any others designated to receive attribution, in any reasonable manner requested by the Licensor (including by pseudonym if designated);
+
+                    ii.	a copyright notice;
+
+                    iii. a notice that refers to this Public License;
+
+                    iv.	a notice that refers to the disclaimer of warranties;
+
+                    v.	a URI or hyperlink to the Licensed Material to the extent reasonably practicable;
+
+               B. indicate if You modified the Licensed Material and retain an indication of any previous modifications; and
+
+               C. indicate the Licensed Material is licensed under this Public License, and include the text of, or the URI or hyperlink to, this Public License.
+
+          2. You may satisfy the conditions in Section 3(a)(1) in any reasonable manner based on the medium, means, and context in which You Share the Licensed Material. For example, it may be reasonable to satisfy the conditions by providing a URI or hyperlink to a resource that includes the required information.
+
+          3. If requested by the Licensor, You must remove any of the information required by Section 3(a)(1)(A) to the extent reasonably practicable.
+
+     b.	ShareAlike.In addition to the conditions in Section 3(a), if You Share Adapted Material You produce, the following conditions also apply.
+
+          1. The Adapter’s License You apply must be a Creative Commons license with the same License Elements, this version or later, or a BY-SA Compatible License.
+
+          2. You must include the text of, or the URI or hyperlink to, the Adapter's License You apply. You may satisfy this condition in any reasonable manner based on the medium, means, and context in which You Share Adapted Material.
+
+          3. You may not offer or impose any additional or different terms or conditions on, or apply any Effective Technological Measures to, Adapted Material that restrict exercise of the rights granted under the Adapter's License You apply.
+
+Section 4 – Sui Generis Database Rights.
+
+Where the Licensed Rights include Sui Generis Database Rights that apply to Your use of the Licensed Material:
+
+     a.	for the avoidance of doubt, Section 2(a)(1) grants You the right to extract, reuse, reproduce, and Share all or a substantial portion of the contents of the database;
+
+     b.	if You include all or a substantial portion of the database contents in a database in which You have Sui Generis Database Rights, then the database in which You have Sui Generis Database Rights (but not its individual contents) is Adapted Material, including for purposes of Section 3(b); and
+
+     c.	You must comply with the conditions in Section 3(a) if You Share all or a substantial portion of the contents of the database.
+For the avoidance of doubt, this Section 4 supplements and does not replace Your obligations under this Public License where the Licensed Rights include other Copyright and Similar Rights.
+
+Section 5 – Disclaimer of Warranties and Limitation of Liability.
+
+     a.	Unless otherwise separately undertaken by the Licensor, to the extent possible, the Licensor offers the Licensed Material as-is and as-available, and makes no representations or warranties of any kind concerning the Licensed Material, whether express, implied, statutory, or other. This includes, without limitation, warranties of title, merchantability, fitness for a particular purpose, non-infringement, absence of latent or other defects, accuracy, or the presence or absence of errors, whether or not known or discoverable. Where disclaimers of warranties are not allowed in full or in part, this disclaimer may not apply to You.
+
+     b.	To the extent possible, in no event will the Licensor be liable to You on any legal theory (including, without limitation, negligence) or otherwise for any direct, special, indirect, incidental, consequential, punitive, exemplary, or other losses, costs, expenses, or damages arising out of this Public License or use of the Licensed Material, even if the Licensor has been advised of the possibility of such losses, costs, expenses, or damages. Where a limitation of liability is not allowed in full or in part, this limitation may not apply to You.
+
+     c.	The disclaimer of warranties and limitation of liability provided above shall be interpreted in a manner that, to the extent possible, most closely approximates an absolute disclaimer and waiver of all liability.
+
+Section 6 – Term and Termination.
+
+     a.	This Public License applies for the term of the Copyright and Similar Rights licensed here. However, if You fail to comply with this Public License, then Your rights under this Public License terminate automatically.
+
+     b.	Where Your right to use the Licensed Material has terminated under Section 6(a), it reinstates:
+
+          1. automatically as of the date the violation is cured, provided it is cured within 30 days of Your discovery of the violation; or
+
+          2. upon express reinstatement by the Licensor.
+
+     c.	For the avoidance of doubt, this Section 6(b) does not affect any right the Licensor may have to seek remedies for Your violations of this Public License.
+
+     d.	For the avoidance of doubt, the Licensor may also offer the Licensed Material under separate terms or conditions or stop distributing the Licensed Material at any time; however, doing so will not terminate this Public License.
+
+     e.	Sections 1, 5, 6, 7, and 8 survive termination of this Public License.
+
+Section 7 – Other Terms and Conditions.
+
+     a.	The Licensor shall not be bound by any additional or different terms or conditions communicated by You unless expressly agreed.
+
+     b.	Any arrangements, understandings, or agreements regarding the Licensed Material not stated herein are separate from and independent of the terms and conditions of this Public License.
+
+Section 8 – Interpretation.
+
+     a.	For the avoidance of doubt, this Public License does not, and shall not be interpreted to, reduce, limit, restrict, or impose conditions on any use of the Licensed Material that could lawfully be made without permission under this Public License.
+
+     b.	To the extent possible, if any provision of this Public License is deemed unenforceable, it shall be automatically reformed to the minimum extent necessary to make it enforceable. If the provision cannot be reformed, it shall be severed from this Public License without affecting the enforceability of the remaining terms and conditions.
+
+     c.	No term or condition of this Public License will be waived and no failure to comply consented to unless expressly agreed to by the Licensor.
+
+     d.	Nothing in this Public License constitutes or may be interpreted as a limitation upon, or waiver of, any privileges and immunities that apply to the Licensor or You, including from the legal processes of any jurisdiction or authority.
+
+Creative Commons is not a party to its public licenses. Notwithstanding, Creative Commons may elect to apply one of its public licenses to material it publishes and in those instances will be considered the “Licensor.” Except for the limited purpose of indicating that material is shared under a Creative Commons public license or as otherwise permitted by the Creative Commons policies published at creativecommons.org/policies, Creative Commons does not authorize the use of the trademark “Creative Commons” or any other trademark or logo of Creative Commons without its prior written consent including, without limitation, in connection with any unauthorized modifications to any of its public licenses or any other arrangements, understandings, or agreements concerning use of licensed material. For the avoidance of doubt, this paragraph does not form part of the public licenses.
+
+Creative Commons may be contacted at creativecommons.org.
diff --git a/LICENSES/MPL-2.0.txt b/LICENSES/MPL-2.0.txt
new file mode 100644
index 0000000..14e2f77
--- /dev/null
+++ b/LICENSES/MPL-2.0.txt
@@ -0,0 +1,373 @@
+Mozilla Public License Version 2.0
+==================================
+
+1. Definitions
+--------------
+
+1.1. "Contributor"
+    means each individual or legal entity that creates, contributes to
+    the creation of, or owns Covered Software.
+
+1.2. "Contributor Version"
+    means the combination of the Contributions of others (if any) used
+    by a Contributor and that particular Contributor's Contribution.
+
+1.3. "Contribution"
+    means Covered Software of a particular Contributor.
+
+1.4. "Covered Software"
+    means Source Code Form to which the initial Contributor has attached
+    the notice in Exhibit A, the Executable Form of such Source Code
+    Form, and Modifications of such Source Code Form, in each case
+    including portions thereof.
+
+1.5. "Incompatible With Secondary Licenses"
+    means
+
+    (a) that the initial Contributor has attached the notice described
+        in Exhibit B to the Covered Software; or
+
+    (b) that the Covered Software was made available under the terms of
+        version 1.1 or earlier of the License, but not also under the
+        terms of a Secondary License.
+
+1.6. "Executable Form"
+    means any form of the work other than Source Code Form.
+
+1.7. "Larger Work"
+    means a work that combines Covered Software with other material, in 
+    a separate file or files, that is not Covered Software.
+
+1.8. "License"
+    means this document.
+
+1.9. "Licensable"
+    means having the right to grant, to the maximum extent possible,
+    whether at the time of the initial grant or subsequently, any and
+    all of the rights conveyed by this License.
+
+1.10. "Modifications"
+    means any of the following:
+
+    (a) any file in Source Code Form that results from an addition to,
+        deletion from, or modification of the contents of Covered
+        Software; or
+
+    (b) any new file in Source Code Form that contains any Covered
+        Software.
+
+1.11. "Patent Claims" of a Contributor
+    means any patent claim(s), including without limitation, method,
+    process, and apparatus claims, in any patent Licensable by such
+    Contributor that would be infringed, but for the grant of the
+    License, by the making, using, selling, offering for sale, having
+    made, import, or transfer of either its Contributions or its
+    Contributor Version.
+
+1.12. "Secondary License"
+    means either the GNU General Public License, Version 2.0, the GNU
+    Lesser General Public License, Version 2.1, the GNU Affero General
+    Public License, Version 3.0, or any later versions of those
+    licenses.
+
+1.13. "Source Code Form"
+    means the form of the work preferred for making modifications.
+
+1.14. "You" (or "Your")
+    means an individual or a legal entity exercising rights under this
+    License. For legal entities, "You" includes any entity that
+    controls, is controlled by, or is under common control with You. For
+    purposes of this definition, "control" means (a) the power, direct
+    or indirect, to cause the direction or management of such entity,
+    whether by contract or otherwise, or (b) ownership of more than
+    fifty percent (50%) of the outstanding shares or beneficial
+    ownership of such entity.
+
+2. License Grants and Conditions
+--------------------------------
+
+2.1. Grants
+
+Each Contributor hereby grants You a world-wide, royalty-free,
+non-exclusive license:
+
+(a) under intellectual property rights (other than patent or trademark)
+    Licensable by such Contributor to use, reproduce, make available,
+    modify, display, perform, distribute, and otherwise exploit its
+    Contributions, either on an unmodified basis, with Modifications, or
+    as part of a Larger Work; and
+
+(b) under Patent Claims of such Contributor to make, use, sell, offer
+    for sale, have made, import, and otherwise transfer either its
+    Contributions or its Contributor Version.
+
+2.2. Effective Date
+
+The licenses granted in Section 2.1 with respect to any Contribution
+become effective for each Contribution on the date the Contributor first
+distributes such Contribution.
+
+2.3. Limitations on Grant Scope
+
+The licenses granted in this Section 2 are the only rights granted under
+this License. No additional rights or licenses will be implied from the
+distribution or licensing of Covered Software under this License.
+Notwithstanding Section 2.1(b) above, no patent license is granted by a
+Contributor:
+
+(a) for any code that a Contributor has removed from Covered Software;
+    or
+
+(b) for infringements caused by: (i) Your and any other third party's
+    modifications of Covered Software, or (ii) the combination of its
+    Contributions with other software (except as part of its Contributor
+    Version); or
+
+(c) under Patent Claims infringed by Covered Software in the absence of
+    its Contributions.
+
+This License does not grant any rights in the trademarks, service marks,
+or logos of any Contributor (except as may be necessary to comply with
+the notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+No Contributor makes additional grants as a result of Your choice to
+distribute the Covered Software under a subsequent version of this
+License (see Section 10.2) or under the terms of a Secondary License (if
+permitted under the terms of Section 3.3).
+
+2.5. Representation
+
+Each Contributor represents that the Contributor believes its
+Contributions are its original creation(s) or it has sufficient rights
+to grant the rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+This License is not intended to limit any rights You have under
+applicable copyright doctrines of fair use, fair dealing, or other
+equivalents.
+
+2.7. Conditions
+
+Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted
+in Section 2.1.
+
+3. Responsibilities
+-------------------
+
+3.1. Distribution of Source Form
+
+All distribution of Covered Software in Source Code Form, including any
+Modifications that You create or to which You contribute, must be under
+the terms of this License. You must inform recipients that the Source
+Code Form of the Covered Software is governed by the terms of this
+License, and how they can obtain a copy of this License. You may not
+attempt to alter or restrict the recipients' rights in the Source Code
+Form.
+
+3.2. Distribution of Executable Form
+
+If You distribute Covered Software in Executable Form then:
+
+(a) such Covered Software must also be made available in Source Code
+    Form, as described in Section 3.1, and You must inform recipients of
+    the Executable Form how they can obtain a copy of such Source Code
+    Form by reasonable means in a timely manner, at a charge no more
+    than the cost of distribution to the recipient; and
+
+(b) You may distribute such Executable Form under the terms of this
+    License, or sublicense it under different terms, provided that the
+    license for the Executable Form does not attempt to limit or alter
+    the recipients' rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+You may create and distribute a Larger Work under terms of Your choice,
+provided that You also comply with the requirements of this License for
+the Covered Software. If the Larger Work is a combination of Covered
+Software with a work governed by one or more Secondary Licenses, and the
+Covered Software is not Incompatible With Secondary Licenses, this
+License permits You to additionally distribute such Covered Software
+under the terms of such Secondary License(s), so that the recipient of
+the Larger Work may, at their option, further distribute the Covered
+Software under the terms of either this License or such Secondary
+License(s).
+
+3.4. Notices
+
+You may not remove or alter the substance of any license notices
+(including copyright notices, patent notices, disclaimers of warranty,
+or limitations of liability) contained within the Source Code Form of
+the Covered Software, except that You may alter any license notices to
+the extent required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+You may choose to offer, and to charge a fee for, warranty, support,
+indemnity or liability obligations to one or more recipients of Covered
+Software. However, You may do so only on Your own behalf, and not on
+behalf of any Contributor. You must make it absolutely clear that any
+such warranty, support, indemnity, or liability obligation is offered by
+You alone, and You hereby agree to indemnify every Contributor for any
+liability incurred by such Contributor as a result of warranty, support,
+indemnity or liability terms You offer. You may include additional
+disclaimers of warranty and limitations of liability specific to any
+jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+---------------------------------------------------
+
+If it is impossible for You to comply with any of the terms of this
+License with respect to some or all of the Covered Software due to
+statute, judicial order, or regulation then You must: (a) comply with
+the terms of this License to the maximum extent possible; and (b)
+describe the limitations and the code they affect. Such description must
+be placed in a text file included with all distributions of the Covered
+Software under this License. Except to the extent prohibited by statute
+or regulation, such description must be sufficiently detailed for a
+recipient of ordinary skill to be able to understand it.
+
+5. Termination
+--------------
+
+5.1. The rights granted under this License will terminate automatically
+if You fail to comply with any of its terms. However, if You become
+compliant, then the rights granted under this License from a particular
+Contributor are reinstated (a) provisionally, unless and until such
+Contributor explicitly and finally terminates Your grants, and (b) on an
+ongoing basis, if such Contributor fails to notify You of the
+non-compliance by some reasonable means prior to 60 days after You have
+come back into compliance. Moreover, Your grants from a particular
+Contributor are reinstated on an ongoing basis if such Contributor
+notifies You of the non-compliance by some reasonable means, this is the
+first time You have received notice of non-compliance with this License
+from such Contributor, and You become compliant prior to 30 days after
+Your receipt of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+infringement claim (excluding declaratory judgment actions,
+counter-claims, and cross-claims) alleging that a Contributor Version
+directly or indirectly infringes any patent, then the rights granted to
+You by any and all Contributors for the Covered Software under Section
+2.1 of this License shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all
+end user license agreements (excluding distributors and resellers) which
+have been validly granted by You or Your distributors under this License
+prior to termination shall survive termination.
+
+************************************************************************
+*                                                                      *
+*  6. Disclaimer of Warranty                                           *
+*  -------------------------                                           *
+*                                                                      *
+*  Covered Software is provided under this License on an "as is"       *
+*  basis, without warranty of any kind, either expressed, implied, or  *
+*  statutory, including, without limitation, warranties that the       *
+*  Covered Software is free of defects, merchantable, fit for a        *
+*  particular purpose or non-infringing. The entire risk as to the     *
+*  quality and performance of the Covered Software is with You.        *
+*  Should any Covered Software prove defective in any respect, You     *
+*  (not any Contributor) assume the cost of any necessary servicing,   *
+*  repair, or correction. This disclaimer of warranty constitutes an   *
+*  essential part of this License. No use of any Covered Software is   *
+*  authorized under this License except under this disclaimer.         *
+*                                                                      *
+************************************************************************
+
+************************************************************************
+*                                                                      *
+*  7. Limitation of Liability                                          *
+*  --------------------------                                          *
+*                                                                      *
+*  Under no circumstances and under no legal theory, whether tort      *
+*  (including negligence), contract, or otherwise, shall any           *
+*  Contributor, or anyone who distributes Covered Software as          *
+*  permitted above, be liable to You for any direct, indirect,         *
+*  special, incidental, or consequential damages of any character      *
+*  including, without limitation, damages for lost profits, loss of    *
+*  goodwill, work stoppage, computer failure or malfunction, or any    *
+*  and all other commercial damages or losses, even if such party      *
+*  shall have been informed of the possibility of such damages. This   *
+*  limitation of liability shall not apply to liability for death or   *
+*  personal injury resulting from such party's negligence to the       *
+*  extent applicable law prohibits such limitation. Some               *
+*  jurisdictions do not allow the exclusion or limitation of           *
+*  incidental or consequential damages, so this exclusion and          *
+*  limitation may not apply to You.                                    *
+*                                                                      *
+************************************************************************
+
+8. Litigation
+-------------
+
+Any litigation relating to this License may be brought only in the
+courts of a jurisdiction where the defendant maintains its principal
+place of business and such litigation shall be governed by laws of that
+jurisdiction, without reference to its conflict-of-law provisions.
+Nothing in this Section shall prevent a party's ability to bring
+cross-claims or counter-claims.
+
+9. Miscellaneous
+----------------
+
+This License represents the complete agreement concerning the subject
+matter hereof. If any provision of this License is held to be
+unenforceable, such provision shall be reformed only to the extent
+necessary to make it enforceable. Any law or regulation which provides
+that the language of a contract shall be construed against the drafter
+shall not be used to construe this License against a Contributor.
+
+10. Versions of the License
+---------------------------
+
+10.1. New Versions
+
+Mozilla Foundation is the license steward. Except as provided in Section
+10.3, no one other than the license steward has the right to modify or
+publish new versions of this License. Each version will be given a
+distinguishing version number.
+
+10.2. Effect of New Versions
+
+You may distribute the Covered Software under the terms of the version
+of the License under which You originally received the Covered Software,
+or under the terms of any subsequent version published by the license
+steward.
+
+10.3. Modified Versions
+
+If you create software not governed by this License, and you want to
+create a new license for such software, you may create and use a
+modified version of this License if you rename the license and remove
+any references to the name of the license steward (except to note that
+such modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary
+Licenses
+
+If You choose to distribute Source Code Form that is Incompatible With
+Secondary Licenses under the terms of this version of the License, the
+notice described in Exhibit B of this License must be attached.
+
+Exhibit A - Source Code Form License Notice
+-------------------------------------------
+
+  This Source Code Form is subject to the terms of the Mozilla Public
+  License, v. 2.0. If a copy of the MPL was not distributed with this
+  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular
+file, then You may include the notice in a location (such as a LICENSE
+file in a relevant directory) where a recipient would be likely to look
+for such a notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - "Incompatible With Secondary Licenses" Notice
+---------------------------------------------------------
+
+  This Source Code Form is "Incompatible With Secondary Licenses", as
+  defined by the Mozilla Public License, v. 2.0.
diff --git a/MAINTAINERS.adoc b/MAINTAINERS.adoc
index 9910dd8..daf8a78 100644
--- a/MAINTAINERS.adoc
+++ b/MAINTAINERS.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 = Maintainers
 :toc: preamble
diff --git a/MAINTAINERS.md b/MAINTAINERS.md
index 97bf7a2..992a59c 100644
--- a/MAINTAINERS.md
+++ b/MAINTAINERS.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Maintainers
diff --git a/PALIMPSEST.adoc b/PALIMPSEST.adoc
index aa923dd..c2afbcc 100644
--- a/PALIMPSEST.adoc
+++ b/PALIMPSEST.adoc
@@ -1,10 +1,10 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 = MPL-2.0
 :toc:
 :toc-placement!:
 
-image:https://img.shields.io/badge/License-PMPL--1.0-blue.svg[License: MPL-2.0,link="https://github.com/hyperpolymath/palimpsest-license"]
+image:https://img.shields.io/badge/License-MPL--2.0-blue.svg[License: MPL-2.0,link="https://github.com/hyperpolymath/palimpsest-license"]
 image:https://img.shields.io/badge/Philosophy-Palimpsest-indigo.svg[Palimpsest,link="https://github.com/hyperpolymath/palimpsest-license"]
 
 toc::[]
@@ -28,7 +28,7 @@ ethical-use, provenance, and lineage requirements.
 
 1. Include the MPL-2.0 license text in `LICENSE`.
 2. Add SPDX headers to source files:
-   `SPDX-License-Identifier: MPL-2.0`
+   `SPDX-License-Identifier: CC-BY-SA-4.0`
 3. Add a Palimpsest badge to your README (see `assets/badges/` and `embed/license-blocks/`).
 
 == Versioning
diff --git a/PROOF-NEEDS.md b/PROOF-NEEDS.md
index 6cba39f..10d9e30 100644
--- a/PROOF-NEEDS.md
+++ b/PROOF-NEEDS.md
@@ -1,4 +1,4 @@
-<!-- SPDX-License-Identifier: MPL-2.0 -->
+<!-- SPDX-License-Identifier: CC-BY-SA-4.0 -->
 <!-- Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk> -->
 <!-- SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath) -->
 <!-- Defines proof obligations. Completion tracked in PROOF-STATUS.md. -->
diff --git a/PROOF-STATUS.md b/PROOF-STATUS.md
index afd02d7..e1c0732 100644
--- a/PROOF-STATUS.md
+++ b/PROOF-STATUS.md
@@ -1,4 +1,4 @@
-<!-- SPDX-License-Identifier: MPL-2.0 -->
+<!-- SPDX-License-Identifier: CC-BY-SA-4.0 -->
 <!-- Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk> -->
 <!-- SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath) -->
 <!-- Tracks proof completion. Obligations defined in PROOF-NEEDS.md. -->
diff --git a/README.adoc b/README.adoc
index 35a415b..e56b200 100644
--- a/README.adoc
+++ b/README.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 # BetLang
 
diff --git a/README.md b/README.md
index 4341777..292891e 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-<!-- SPDX-License-Identifier: MPL-2.0 -->
+<!-- SPDX-License-Identifier: CC-BY-SA-4.0 -->
 <!-- Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk> -->
 <!-- SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath) -->
 
diff --git a/ROADMAP.adoc b/ROADMAP.adoc
index 17df4b4..168854a 100644
--- a/ROADMAP.adoc
+++ b/ROADMAP.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 = BetLang Roadmap
 
diff --git a/RSR_COMPLIANCE.adoc b/RSR_COMPLIANCE.adoc
index bc84d6c..06572f9 100644
--- a/RSR_COMPLIANCE.adoc
+++ b/RSR_COMPLIANCE.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 = RSR Compliance: betlang
 :toc:
diff --git a/RSR_OUTLINE.adoc b/RSR_OUTLINE.adoc
index 3a30135..2d07b49 100644
--- a/RSR_OUTLINE.adoc
+++ b/RSR_OUTLINE.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 = RSR Template Repository
 
@@ -211,7 +211,7 @@ This template is part of:
 
 == License
 
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 
 == Links
 
diff --git a/RUST-STATUS.md b/RUST-STATUS.md
index 4bb0820..028b976 100644
--- a/RUST-STATUS.md
+++ b/RUST-STATUS.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Rust Compiler Status
diff --git a/SAFETY-FEATURES.md b/SAFETY-FEATURES.md
index 02da055..5543606 100644
--- a/SAFETY-FEATURES.md
+++ b/SAFETY-FEATURES.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # BetLang Safety Features
diff --git a/SECURITY.md b/SECURITY.md
index f3c9ca2..31a4215 100644
--- a/SECURITY.md
+++ b/SECURITY.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Security Policy
diff --git a/TOOLING.md b/TOOLING.md
index f9ad131..47d3d4e 100644
--- a/TOOLING.md
+++ b/TOOLING.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Betlang Optional Tooling
diff --git a/TPCF.md b/TPCF.md
index 610fe20..fd9febd 100644
--- a/TPCF.md
+++ b/TPCF.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Tri-Perimeter Contribution Framework (TPCF)
diff --git a/bindings/chapel/examples/basic.chpl b/bindings/chapel/examples/basic.chpl
index 35b7077..1a5d68c 100644
--- a/bindings/chapel/examples/basic.chpl
+++ b/bindings/chapel/examples/basic.chpl
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MIT OR Apache-2.0
+// SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 // Basic example of using Betlang from Chapel
 
 // Compile with:
diff --git a/bindings/julia/src/Betlang.jl b/bindings/julia/src/Betlang.jl
index cd63f42..df68264 100644
--- a/bindings/julia/src/Betlang.jl
+++ b/bindings/julia/src/Betlang.jl
@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: MIT OR Apache-2.0
+# SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 """
     Betlang
 
diff --git a/conformance/README.md b/conformance/README.md
index 552e3e7..ae4227b 100644
--- a/conformance/README.md
+++ b/conformance/README.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Betlang Conformance Test Corpus
diff --git a/containers/Containerfile b/containers/Containerfile
index 509624f..fb95aac 100644
--- a/containers/Containerfile
+++ b/containers/Containerfile
@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: MIT OR Apache-2.0
+# SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 # Betlang Container Image
 #
 # Build with nerdctl (preferred) or podman:
diff --git a/containers/Containerfile.dev b/containers/Containerfile.dev
index bb4ba4a..80ebefb 100644
--- a/containers/Containerfile.dev
+++ b/containers/Containerfile.dev
@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: MIT OR Apache-2.0
+# SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 # Betlang Development Container
 #
 # Build with nerdctl or podman:
diff --git a/containers/build.sh b/containers/build.sh
index ff89001..ed65034 100755
--- a/containers/build.sh
+++ b/containers/build.sh
@@ -1,5 +1,5 @@
 #!/bin/bash
-# SPDX-License-Identifier: MIT OR Apache-2.0
+# SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 # Build script for Betlang containers
 #
 # Prefers nerdctl, falls back to podman
diff --git a/contractiles/README.adoc b/contractiles/README.adoc
index a4b404f..a769476 100644
--- a/contractiles/README.adoc
+++ b/contractiles/README.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 // SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath)
 // @taxonomy: contractiles/readme
diff --git a/docs/AFFINESCRIPT-ALIGNMENT.adoc b/docs/AFFINESCRIPT-ALIGNMENT.adoc
index ded967f..91d25a7 100644
--- a/docs/AFFINESCRIPT-ALIGNMENT.adoc
+++ b/docs/AFFINESCRIPT-ALIGNMENT.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 // SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath)
 // @taxonomy: docs/affinescript-alignment
diff --git a/docs/BETLANG-COMPARISON.md b/docs/BETLANG-COMPARISON.md
index 89d1df9..e17e48c 100644
--- a/docs/BETLANG-COMPARISON.md
+++ b/docs/BETLANG-COMPARISON.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # StatistEase + BetLang Capability Comparison
diff --git a/docs/CITATIONS.adoc b/docs/CITATIONS.adoc
index 846cce3..fe7becd 100644
--- a/docs/CITATIONS.adoc
+++ b/docs/CITATIONS.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 = betlang - Citation Guide
 :toc:
diff --git a/docs/api-reference.md b/docs/api-reference.md
index dd7397a..66765c5 100644
--- a/docs/api-reference.md
+++ b/docs/api-reference.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # betlang API Reference
diff --git a/docs/architecture.md b/docs/architecture.md
index fc04e57..1a893b8 100644
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Project Architecture
diff --git a/docs/decisions/2026-06-15-L0-canonical-identity.adoc b/docs/decisions/2026-06-15-L0-canonical-identity.adoc
index f7207b4..639c24c 100644
--- a/docs/decisions/2026-06-15-L0-canonical-identity.adoc
+++ b/docs/decisions/2026-06-15-L0-canonical-identity.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 // SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath)
 = L0 — Canonical identity of betlang
diff --git a/docs/decisions/2026-06-15-betlang-core-plan.adoc b/docs/decisions/2026-06-15-betlang-core-plan.adoc
index 8211bb2..ee9a5af 100644
--- a/docs/decisions/2026-06-15-betlang-core-plan.adoc
+++ b/docs/decisions/2026-06-15-betlang-core-plan.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 // SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath)
 = betlang — Core Build Plan (core → post-core tier)
diff --git a/docs/decisions/2026-06-15-betlang-wiring-and-bet-dist-t.adoc b/docs/decisions/2026-06-15-betlang-wiring-and-bet-dist-t.adoc
index 8f1366b..5608a2f 100644
--- a/docs/decisions/2026-06-15-betlang-wiring-and-bet-dist-t.adoc
+++ b/docs/decisions/2026-06-15-betlang-wiring-and-bet-dist-t.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 // SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath)
 = Design-decision log — betlang wiring pass & `bet : Dist T` (2026-06-15)
diff --git a/docs/echo-types.adoc b/docs/echo-types.adoc
index ea16f0c..df4eb2c 100644
--- a/docs/echo-types.adoc
+++ b/docs/echo-types.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 // SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath)
 // @taxonomy: docs/echo-types
diff --git a/docs/experimental-ideas.md b/docs/experimental-ideas.md
index abfffba..a3d5ade 100644
--- a/docs/experimental-ideas.md
+++ b/docs/experimental-ideas.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Betlang experimental ideas
diff --git a/docs/hyperpolymath-julia-integration.md b/docs/hyperpolymath-julia-integration.md
index 7796989..0e95f7a 100644
--- a/docs/hyperpolymath-julia-integration.md
+++ b/docs/hyperpolymath-julia-integration.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # BetLang Integration with Hyperpolymath Julia Packages
diff --git a/docs/julia-backend-design.md b/docs/julia-backend-design.md
index 1b19bdb..d6426fb 100644
--- a/docs/julia-backend-design.md
+++ b/docs/julia-backend-design.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # BetLang Julia Backend Design (v0.8)
diff --git a/docs/proof-debt.adoc b/docs/proof-debt.adoc
index f787731..4378324 100644
--- a/docs/proof-debt.adoc
+++ b/docs/proof-debt.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 // SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath)
 = Proof debt
diff --git a/docs/proof-debt.md b/docs/proof-debt.md
index 4d7020e..f6a8dff 100644
--- a/docs/proof-debt.md
+++ b/docs/proof-debt.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Proof Debt — betlang
diff --git a/docs/semantics.md b/docs/semantics.md
index c69e750..8f914de 100644
--- a/docs/semantics.md
+++ b/docs/semantics.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # betlang Semantics
diff --git a/docs/tech-debt-2026-05-26.md b/docs/tech-debt-2026-05-26.md
index 77f006b..a28375d 100644
--- a/docs/tech-debt-2026-05-26.md
+++ b/docs/tech-debt-2026-05-26.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Tech-Debt Audit — betlang — 2026-05-26
diff --git a/docs/tutorial.md b/docs/tutorial.md
index 991a335..4f554f2 100644
--- a/docs/tutorial.md
+++ b/docs/tutorial.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # betlang Tutorial
diff --git a/docs/v3-optimization-workflow.md b/docs/v3-optimization-workflow.md
index 4d87796..626dfd7 100644
--- a/docs/v3-optimization-workflow.md
+++ b/docs/v3-optimization-workflow.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Betlang v3 optimization workflow
diff --git a/editors/neovim/README.md b/editors/neovim/README.md
index b497921..4484014 100644
--- a/editors/neovim/README.md
+++ b/editors/neovim/README.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Betlang Neovim/Vim Plugin
diff --git a/editors/neovim/ftdetect/betlang.vim b/editors/neovim/ftdetect/betlang.vim
index 726e2de..0b284a0 100644
--- a/editors/neovim/ftdetect/betlang.vim
+++ b/editors/neovim/ftdetect/betlang.vim
@@ -1,4 +1,4 @@
-" SPDX-License-Identifier: MIT OR Apache-2.0
+" SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 " Filetype detection for Betlang
 
 autocmd BufNewFile,BufRead *.bet,*.betlang setfiletype betlang
diff --git a/editors/neovim/ftplugin/betlang.vim b/editors/neovim/ftplugin/betlang.vim
index a771a9c..923ff60 100644
--- a/editors/neovim/ftplugin/betlang.vim
+++ b/editors/neovim/ftplugin/betlang.vim
@@ -1,4 +1,4 @@
-" SPDX-License-Identifier: MIT OR Apache-2.0
+" SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 " Filetype plugin for Betlang
 
 if exists("b:did_ftplugin")
diff --git a/editors/neovim/lua/betlang/init.lua b/editors/neovim/lua/betlang/init.lua
index 8c5475b..8aefec1 100644
--- a/editors/neovim/lua/betlang/init.lua
+++ b/editors/neovim/lua/betlang/init.lua
@@ -1,4 +1,4 @@
--- SPDX-License-Identifier: MIT OR Apache-2.0
+-- SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 -- Betlang Neovim plugin
 
 local M = {}
diff --git a/editors/neovim/plugin/betlang.vim b/editors/neovim/plugin/betlang.vim
index 3f1085d..cb1315a 100644
--- a/editors/neovim/plugin/betlang.vim
+++ b/editors/neovim/plugin/betlang.vim
@@ -1,4 +1,4 @@
-" SPDX-License-Identifier: MIT OR Apache-2.0
+" SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 " Betlang Neovim/Vim plugin entry point
 
 if exists('g:loaded_betlang')
diff --git a/editors/neovim/syntax/betlang.vim b/editors/neovim/syntax/betlang.vim
index e685d13..ef0a1cb 100644
--- a/editors/neovim/syntax/betlang.vim
+++ b/editors/neovim/syntax/betlang.vim
@@ -1,4 +1,4 @@
-" SPDX-License-Identifier: MIT OR Apache-2.0
+" SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 " Vim syntax file for Betlang
 
 if exists("b:current_syntax")
diff --git a/julia-backend/README.md b/julia-backend/README.md
index 8390b8b..0e3535e 100644
--- a/julia-backend/README.md
+++ b/julia-backend/README.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # BetLang Julia Backend (v0.8.0-dev)
diff --git a/lsp/bet-lsp/src/bet_lsp.gleam b/lsp/bet-lsp/src/bet_lsp.gleam
index c09897e..46610bb 100644
--- a/lsp/bet-lsp/src/bet_lsp.gleam
+++ b/lsp/bet-lsp/src/bet_lsp.gleam
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MIT OR Apache-2.0
+// SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 //// Betlang Language Server Protocol Implementation
 ////
 //// This module provides the main entry point and LSP server logic.
diff --git a/lsp/bet-lsp/src/bet_lsp/analyzer.gleam b/lsp/bet-lsp/src/bet_lsp/analyzer.gleam
index 1a505c8..f93a317 100644
--- a/lsp/bet-lsp/src/bet_lsp/analyzer.gleam
+++ b/lsp/bet-lsp/src/bet_lsp/analyzer.gleam
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MIT OR Apache-2.0
+// SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 //// Code analysis for Betlang LSP
 ////
 //// Provides parsing, diagnostics, hover info, and completions.
diff --git a/lsp/bet-lsp/src/bet_lsp/handlers.gleam b/lsp/bet-lsp/src/bet_lsp/handlers.gleam
index 21d407f..3de2cda 100644
--- a/lsp/bet-lsp/src/bet_lsp/handlers.gleam
+++ b/lsp/bet-lsp/src/bet_lsp/handlers.gleam
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MIT OR Apache-2.0
+// SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 //// LSP request handlers for Betlang
 
 import gleam/dynamic.{type Dynamic}
diff --git a/lsp/bet-lsp/src/bet_lsp/jsonrpc.gleam b/lsp/bet-lsp/src/bet_lsp/jsonrpc.gleam
index cf23f8a..5b1f3a8 100644
--- a/lsp/bet-lsp/src/bet_lsp/jsonrpc.gleam
+++ b/lsp/bet-lsp/src/bet_lsp/jsonrpc.gleam
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MIT OR Apache-2.0
+// SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 //// JSON-RPC 2.0 implementation for LSP
 
 import gleam/dynamic.{type Dynamic}
diff --git a/lsp/bet-lsp/src/bet_lsp/protocol.gleam b/lsp/bet-lsp/src/bet_lsp/protocol.gleam
index f80de54..7156d2f 100644
--- a/lsp/bet-lsp/src/bet_lsp/protocol.gleam
+++ b/lsp/bet-lsp/src/bet_lsp/protocol.gleam
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MIT OR Apache-2.0
+// SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 //// LSP Protocol types and constants
 
 /// Text document sync kinds
diff --git a/lsp/bet-lsp/src/bet_lsp/state.gleam b/lsp/bet-lsp/src/bet_lsp/state.gleam
index 971dff3..8581c24 100644
--- a/lsp/bet-lsp/src/bet_lsp/state.gleam
+++ b/lsp/bet-lsp/src/bet_lsp/state.gleam
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MIT OR Apache-2.0
+// SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 //// Server state management for Betlang LSP
 
 import gleam/dict.{type Dict}
diff --git a/lsp/bet-lsp/src/bet_lsp_io.erl b/lsp/bet-lsp/src/bet_lsp_io.erl
index 013c3b5..1fdb9f7 100644
--- a/lsp/bet-lsp/src/bet_lsp_io.erl
+++ b/lsp/bet-lsp/src/bet_lsp_io.erl
@@ -1,4 +1,4 @@
-%% SPDX-License-Identifier: MIT OR Apache-2.0
+%% SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 %% Erlang I/O functions for Betlang LSP
 
 -module(bet_lsp_io).
diff --git a/packaging/scripts/build-all.sh b/packaging/scripts/build-all.sh
index a5c14c3..891ac95 100755
--- a/packaging/scripts/build-all.sh
+++ b/packaging/scripts/build-all.sh
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# SPDX-License-Identifier: MIT OR Apache-2.0
+# SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 # Build all betlang packages
 
 set -euo pipefail
@@ -181,7 +181,7 @@ build_homebrew() {
     info "Building Homebrew formula..."
 
     cat > "$PROJECT_ROOT/packaging/homebrew/betlang.rb" << 'EOF'
-# SPDX-License-Identifier: MIT OR Apache-2.0
+# SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 class Betlang < Formula
   desc "Ternary probabilistic programming language"
   homepage "https://github.com/hyperpolymath/betlang"
@@ -229,7 +229,7 @@ build_aur() {
     info "Building AUR PKGBUILD..."
 
     cat > "$PROJECT_ROOT/packaging/aur/PKGBUILD" << 'EOF'
-# SPDX-License-Identifier: MIT OR Apache-2.0
+# SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 # Maintainer: Hyperpolymath <support@hyperpolymath.com>
 
 pkgname=betlang
@@ -312,7 +312,7 @@ build_flatpak() {
     info "Building Flatpak manifest..."
 
     cat > "$PROJECT_ROOT/packaging/flatpak/com.hyperpolymath.betlang.yml" << 'EOF'
-# SPDX-License-Identifier: MIT OR Apache-2.0
+# SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 app-id: com.hyperpolymath.betlang
 runtime: org.freedesktop.Platform
 runtime-version: '23.08'
@@ -400,7 +400,7 @@ EOF
     # Chocolatey nuspec
     cat > "$PROJECT_ROOT/packaging/windows/betlang.nuspec" << 'EOF'
 <?xml version="1.0" encoding="utf-8"?>
-<!-- SPDX-License-Identifier: MIT OR Apache-2.0 -->
+<!-- SPDX-License-Identifier: MPL-2.0 OR Apache-2.0 -->
 <package xmlns="http://schemas.microsoft.com/packaging/2015/06/nuspec.xsd">
   <metadata>
     <id>betlang</id>
@@ -424,7 +424,7 @@ EOF
     # winget manifest
     mkdir -p "$PROJECT_ROOT/packaging/windows/winget"
     cat > "$PROJECT_ROOT/packaging/windows/winget/Hyperpolymath.Betlang.yaml" << 'EOF'
-# SPDX-License-Identifier: MIT OR Apache-2.0
+# SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 PackageIdentifier: Hyperpolymath.Betlang
 PackageVersion: 0.1.0
 PackageLocale: en-US
diff --git a/packaging/scripts/release.sh b/packaging/scripts/release.sh
index 46b276b..4da7b30 100755
--- a/packaging/scripts/release.sh
+++ b/packaging/scripts/release.sh
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# SPDX-License-Identifier: MIT OR Apache-2.0
+# SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 # Create a release with all platform binaries
 
 set -euo pipefail
diff --git a/playground/ARCHITECTURE.adoc b/playground/ARCHITECTURE.adoc
index 081d7e3..a98b517 100644
--- a/playground/ARCHITECTURE.adoc
+++ b/playground/ARCHITECTURE.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 = Architecture
 
diff --git a/playground/README.adoc b/playground/README.adoc
index e151337..387f310 100644
--- a/playground/README.adoc
+++ b/playground/README.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 = Betlang Playground Directory
 :toc:
diff --git a/playground/docs/CITATIONS.adoc b/playground/docs/CITATIONS.adoc
index 52ba528..8cb2e4e 100644
--- a/playground/docs/CITATIONS.adoc
+++ b/playground/docs/CITATIONS.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 = RSR-template-repo - Citation Guide
 :toc:
diff --git a/proofs/README.md b/proofs/README.md
index 0b7d8fb..0cede7b 100644
--- a/proofs/README.md
+++ b/proofs/README.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Betlang Academic Proofs and Documentation
diff --git a/proofs/complexity/computational-complexity.md b/proofs/complexity/computational-complexity.md
index 981b366..8fde2a8 100644
--- a/proofs/complexity/computational-complexity.md
+++ b/proofs/complexity/computational-complexity.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Computational Complexity Analysis of Betlang
diff --git a/proofs/formal-semantics.md b/proofs/formal-semantics.md
index b6e50d2..19c273b 100644
--- a/proofs/formal-semantics.md
+++ b/proofs/formal-semantics.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Formal Semantics of Betlang
diff --git a/proofs/mathematical-foundations.md b/proofs/mathematical-foundations.md
index 9b1776e..a4a387d 100644
--- a/proofs/mathematical-foundations.md
+++ b/proofs/mathematical-foundations.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Mathematical Foundations of Betlang
diff --git a/proofs/papers/betlang-whitepaper.md b/proofs/papers/betlang-whitepaper.md
index 35319ec..bfe3dda 100644
--- a/proofs/papers/betlang-whitepaper.md
+++ b/proofs/papers/betlang-whitepaper.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Betlang: A Ternary Probabilistic Programming Language
diff --git a/proofs/papers/betlang-whitepaper.md.invariants.md b/proofs/papers/betlang-whitepaper.md.invariants.md
index e230fb9..5ba0e90 100644
--- a/proofs/papers/betlang-whitepaper.md.invariants.md
+++ b/proofs/papers/betlang-whitepaper.md.invariants.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Invariant Path Scan: betlang-whitepaper.md
diff --git a/proofs/papers/ppl-comparison.md b/proofs/papers/ppl-comparison.md
index 7581438..c0a17b1 100644
--- a/proofs/papers/ppl-comparison.md
+++ b/proofs/papers/ppl-comparison.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Comparative Analysis: Betlang and Probabilistic Programming Languages
diff --git a/proofs/theorems/category-theory.md b/proofs/theorems/category-theory.md
index 9e04cb6..1342002 100644
--- a/proofs/theorems/category-theory.md
+++ b/proofs/theorems/category-theory.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Category-Theoretic Foundations of Betlang
diff --git a/proofs/theorems/convergence-statistics.md b/proofs/theorems/convergence-statistics.md
index f71e567..b0e292f 100644
--- a/proofs/theorems/convergence-statistics.md
+++ b/proofs/theorems/convergence-statistics.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Convergence and Statistical Proofs for Betlang
diff --git a/proofs/theorems/information-theory.md b/proofs/theorems/information-theory.md
index 6848b1b..a43887a 100644
--- a/proofs/theorems/information-theory.md
+++ b/proofs/theorems/information-theory.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Information-Theoretic Analysis of Betlang
diff --git a/proofs/theorems/mcmc-inference.md b/proofs/theorems/mcmc-inference.md
index 7908f8f..4b99118 100644
--- a/proofs/theorems/mcmc-inference.md
+++ b/proofs/theorems/mcmc-inference.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # MCMC and Inference Correctness Proofs
diff --git a/proofs/theorems/measure-theory.md b/proofs/theorems/measure-theory.md
index b6e816b..fcebe23 100644
--- a/proofs/theorems/measure-theory.md
+++ b/proofs/theorems/measure-theory.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Measure-Theoretic Foundations of Betlang
diff --git a/proofs/theorems/soundness-completeness.md b/proofs/theorems/soundness-completeness.md
index 30cba90..6da6c25 100644
--- a/proofs/theorems/soundness-completeness.md
+++ b/proofs/theorems/soundness-completeness.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Soundness and Completeness Theorems for Betlang
diff --git a/proofs/theorems/termination-analysis.md b/proofs/theorems/termination-analysis.md
index d461428..137c105 100644
--- a/proofs/theorems/termination-analysis.md
+++ b/proofs/theorems/termination-analysis.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Termination Analysis for Betlang
diff --git a/proofs/theorems/type-theory.md b/proofs/theorems/type-theory.md
index 055ad54..6c55ab6 100644
--- a/proofs/theorems/type-theory.md
+++ b/proofs/theorems/type-theory.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Type Theory and Probability Monad Proofs
diff --git a/proofs/verification/formal-verification.md b/proofs/verification/formal-verification.md
index e914326..1268a0a 100644
--- a/proofs/verification/formal-verification.md
+++ b/proofs/verification/formal-verification.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 # Formal Verification Specifications for Betlang
diff --git a/site/index.md b/site/index.md
index 9656602..b86c766 100644
--- a/site/index.md
+++ b/site/index.md
@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
 ---
diff --git a/spec/README.adoc b/spec/README.adoc
index 9286859..ccca586 100644
--- a/spec/README.adoc
+++ b/spec/README.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 // @taxonomy: spec/index
 = betlang — Specification Directory
diff --git a/spec/system-specs.md b/spec/system-specs.md
index 69b1f01..63eece1 100644
--- a/spec/system-specs.md
+++ b/spec/system-specs.md
@@ -1,8 +1,8 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 -->
-# SPDX-License-Identifier: MPL-2.0
+# SPDX-License-Identifier: CC-BY-SA-4.0
 # Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>
 
 # BetLang System Specifications
diff --git a/tools/bet-dap/Cargo.toml b/tools/bet-dap/Cargo.toml
index bd1f0cd..a73ee58 100644
--- a/tools/bet-dap/Cargo.toml
+++ b/tools/bet-dap/Cargo.toml
@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: MIT OR Apache-2.0
+# SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 # Optional tooling - NOT authoritative
 
 [package]
diff --git a/tools/bet-lsp/Cargo.toml b/tools/bet-lsp/Cargo.toml
index 0ef0481..6673344 100644
--- a/tools/bet-lsp/Cargo.toml
+++ b/tools/bet-lsp/Cargo.toml
@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: MIT OR Apache-2.0
+# SPDX-License-Identifier: MPL-2.0 OR Apache-2.0
 # Optional tooling - NOT authoritative
 
 [package]
diff --git a/ui/README.adoc b/ui/README.adoc
index 0ee8c55..adb3c1b 100644
--- a/ui/README.adoc
+++ b/ui/README.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 = Betlang Playground
 :toc:
diff --git a/ui/launcher/README.adoc b/ui/launcher/README.adoc
index 0af327b..78a530f 100644
--- a/ui/launcher/README.adoc
+++ b/ui/launcher/README.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 = Betlang Playground Launcher
 :toc:
diff --git a/verification/README.adoc b/verification/README.adoc
index 92b6777..afc85b1 100644
--- a/verification/README.adoc
+++ b/verification/README.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 // @taxonomy: verification/index
 = betlang — Verification Directory
diff --git a/verification/coverage/README.adoc b/verification/coverage/README.adoc
index cc1dc89..25fa36f 100644
--- a/verification/coverage/README.adoc
+++ b/verification/coverage/README.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 // @taxonomy: verification/coverage
 = Verification — Coverage
diff --git a/verification/safety_case/README.adoc b/verification/safety_case/README.adoc
index ff1842b..8172f9c 100644
--- a/verification/safety_case/README.adoc
+++ b/verification/safety_case/README.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 // @taxonomy: verification/safety_case
 = Verification — Safety Case
diff --git a/verification/simulations/README.adoc b/verification/simulations/README.adoc
index 32cb243..af18da5 100644
--- a/verification/simulations/README.adoc
+++ b/verification/simulations/README.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 // @taxonomy: verification/simulations
 = Verification — Simulations
diff --git a/verification/traceability/README.adoc b/verification/traceability/README.adoc
index 0a03636..e51879f 100644
--- a/verification/traceability/README.adoc
+++ b/verification/traceability/README.adoc
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 // @taxonomy: verification/traceability
 = Verification — Traceability
diff --git a/wiki/Architecture.md b/wiki/Architecture.md
index c64e96c..1a760ae 100644
--- a/wiki/Architecture.md
+++ b/wiki/Architecture.md
@@ -1,4 +1,4 @@
-<!-- SPDX-License-Identifier: MPL-2.0 -->
+<!-- SPDX-License-Identifier: CC-BY-SA-4.0 -->
 <!-- Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk> -->
 <!-- SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath) -->
 # Architecture
diff --git a/wiki/Echo-Types.md b/wiki/Echo-Types.md
index 532ea98..3b51f2b 100644
--- a/wiki/Echo-Types.md
+++ b/wiki/Echo-Types.md
@@ -1,4 +1,4 @@
-<!-- SPDX-License-Identifier: MPL-2.0 -->
+<!-- SPDX-License-Identifier: CC-BY-SA-4.0 -->
 <!-- Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk> -->
 <!-- SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath) -->
 # Echo Types — Structured Loss as a Typed Object
diff --git a/wiki/Formal-Verification.md b/wiki/Formal-Verification.md
index 7e76806..193a564 100644
--- a/wiki/Formal-Verification.md
+++ b/wiki/Formal-Verification.md
@@ -1,4 +1,4 @@
-<!-- SPDX-License-Identifier: MPL-2.0 -->
+<!-- SPDX-License-Identifier: CC-BY-SA-4.0 -->
 <!-- Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk> -->
 <!-- SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath) -->
 # Formal Verification — and How BetLang Compares
diff --git a/wiki/Home.md b/wiki/Home.md
index e4197d6..5616369 100644
--- a/wiki/Home.md
+++ b/wiki/Home.md
@@ -1,4 +1,4 @@
-<!-- SPDX-License-Identifier: MPL-2.0 -->
+<!-- SPDX-License-Identifier: CC-BY-SA-4.0 -->
 <!-- Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk> -->
 <!-- SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath) -->
 # BetLang Wiki
diff --git a/wiki/Number-Tower.md b/wiki/Number-Tower.md
index 1f5b68a..8f86407 100644
--- a/wiki/Number-Tower.md
+++ b/wiki/Number-Tower.md
@@ -1,4 +1,4 @@
-<!-- SPDX-License-Identifier: MPL-2.0 -->
+<!-- SPDX-License-Identifier: CC-BY-SA-4.0 -->
 <!-- Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk> -->
 <!-- SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath) -->
 # The Uncertainty Number Tower
diff --git a/wiki/Roadmap.md b/wiki/Roadmap.md
index ef1aff2..3c14268 100644
--- a/wiki/Roadmap.md
+++ b/wiki/Roadmap.md
@@ -1,4 +1,4 @@
-<!-- SPDX-License-Identifier: MPL-2.0 -->
+<!-- SPDX-License-Identifier: CC-BY-SA-4.0 -->
 <!-- Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk> -->
 <!-- SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath) -->
 # Roadmap
diff --git a/wiki/Ternary-Semantics.md b/wiki/Ternary-Semantics.md
index b688d38..63eea8a 100644
--- a/wiki/Ternary-Semantics.md
+++ b/wiki/Ternary-Semantics.md
@@ -1,4 +1,4 @@
-<!-- SPDX-License-Identifier: MPL-2.0 -->
+<!-- SPDX-License-Identifier: CC-BY-SA-4.0 -->
 <!-- Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk> -->
 <!-- SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath) -->
 # The `bet` Primitive & Ternary Semantics
diff --git a/wiki/Type-System.md b/wiki/Type-System.md
index fb64015..f407322 100644
--- a/wiki/Type-System.md
+++ b/wiki/Type-System.md
@@ -1,4 +1,4 @@
-<!-- SPDX-License-Identifier: MPL-2.0 -->
+<!-- SPDX-License-Identifier: CC-BY-SA-4.0 -->
 <!-- Owner: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk> -->
 <!-- SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath) -->
 # Type System
