diff --git a/CHANGELOG.md b/CHANGELOG.md
index ed988b9..9ebe5a8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,7 +7,7 @@ All notable changes to Cairn are recorded here. Format follows
 Per the [documentation policy](docs/governance/documentation-policy.md), every meaningful change
 updates this file.
 
-## [Unreleased] — Milestone M4: BYOM recovery library (in-repo, 0.x — ships nothing outward)
+## [0.3.0] — 2026-07-02 — Milestone M4: BYOM recovery library (in-repo, 0.x — ships nothing outward)
 
 Cairn's recovery **mechanism**, repackaged as a **bring-your-own-model (BYOM) library**: a clean,
 documented public API an outside developer drops into *their own* agent with *their own* model and
diff --git a/pyproject.toml b/pyproject.toml
index 0dbb322..2f8b0b3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,8 +4,8 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "cairn"
-version = "0.2.0"
-description = "Recoverable long-horizon agents — reference harness + recovery-faithful live benchmark"
+version = "0.3.0"
+description = "Recoverable long-horizon agents — a bring-your-own-model recovery library, reference harness, and recovery-faithful benchmark"
 readme = "README.md"
 requires-python = ">=3.10"
 license = { text = "Apache-2.0" }
diff --git a/src/cairn/__init__.py b/src/cairn/__init__.py
index c6e40e2..271e1d4 100644
--- a/src/cairn/__init__.py
+++ b/src/cairn/__init__.py
@@ -10,7 +10,7 @@
 confirmed — see docs/research/claims-registry.md).
 """
 
-__version__ = "0.2.0"
+__version__ = "0.3.0"
 
 from .contract import CheckpointStore, EffectLedger, World
 from .harness.effects import EffectfulTool, EscalationRequired, Resolution