diff --git a/CHANGELOG.md b/CHANGELOG.md
index 90ef7cd..2eb5dd8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,21 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.1.3] - 2026-05-19
+
+### Added
+
+- New **Built with AI · Powered by StrayMark** section in README acknowledging
+  the project's AI-assisted development process and its use of
+  [StrayMark](https://straymark.dev) — a CLI for cognitive discipline in
+  AI-assisted engineering — for decision tracking and governance.
+- New **Copyright** section in README identifying Strange Days Tech S.A.S. de
+  C.V. ([strangedays.tech](https://strangedays.tech/)) as the original author
+  and intellectual-property holder.
+- `SPDX-License-Identifier: MIT OR Apache-2.0` header with copyright
+  attribution on every Rust source file in the library, in line with Rust
+  ecosystem conventions.
+
 ## [0.1.2] - 2026-04-02
 
 ### Fixed
@@ -51,7 +66,8 @@ Initial release on [crates.io](https://crates.io/crates/arborist-metrics).
 - Composite feature flags: `default` (6 languages) and `all` (12 languages).
 - 177 tests covering all languages, metrics, thresholds, serialization, and edge cases.
 
-[unreleased]: https://github.com/StrangeDaysTech/arborist/compare/v0.1.2...HEAD
+[unreleased]: https://github.com/StrangeDaysTech/arborist/compare/v0.1.3...HEAD
+[0.1.3]: https://github.com/StrangeDaysTech/arborist/compare/v0.1.2...v0.1.3
 [0.1.2]: https://github.com/StrangeDaysTech/arborist/compare/v0.1.1...v0.1.2
 [0.1.1]: https://github.com/StrangeDaysTech/arborist/compare/v0.1.0...v0.1.1
 [0.1.0]: https://github.com/StrangeDaysTech/arborist/releases/tag/v0.1.0
diff --git a/Cargo.lock b/Cargo.lock
index c5230b1..9cecbf6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -13,7 +13,7 @@ dependencies = [
 
 [[package]]
 name = "arborist-metrics"
-version = "0.1.2"
+version = "0.1.3"
 dependencies = [
  "serde",
  "serde_json",
diff --git a/Cargo.toml b/Cargo.toml
index 379fe6c..5ffa8ad 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "arborist-metrics"
-version = "0.1.2"
+version = "0.1.3"
 edition = "2024"
 description = "Multi-language code complexity metrics (cognitive, cyclomatic, SLOC) powered by tree-sitter"
 license = "MIT OR Apache-2.0"
diff --git a/README.md b/README.md
index cdf5895..51e5d87 100644
--- a/README.md
+++ b/README.md
@@ -200,6 +200,22 @@ Physical source lines of code, excluding blank lines and comment-only lines.
 4. Create 6 test fixtures in `tests/fixtures/<lang>/`
 5. Write integration tests
 
+## Built with AI · Powered by StrayMark
+
+Arborist is an experiment in **disciplined AI-assisted development**.
+The implementation — tree-sitter integration, the 177-test suite, all 12
+language profiles — was authored largely by AI agents under human direction.
+
+To make that velocity sustainable, we use **[StrayMark](https://straymark.dev)**:
+a CLI for *cognitive discipline in AI-assisted engineering*. It turned every
+architectural choice into an AIDEC record, every implementation block into
+an AILOG, and the test plan into a TES — all under `.straymark/`, append-only
+and audit-ready. The governance artifacts emerged **alongside** the code,
+not as homework after.
+
+> StrayMark is built by Strange Days Tech — the same team behind Arborist.
+> It is the tool we made to solve our own problem.
+
 ## License
 
 Licensed under either of: