diff --git a/CHANGELOG.md b/CHANGELOG.md
index d2cf1aea..45a78d3a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,15 @@
 # Changelog
 
+## [0.9.0](https://github.com/agentclientprotocol/agent-client-protocol/compare/v0.8.0...v0.9.0) - 2025-12-01
+
+This release defines the `_meta` properties in the schema as intended and currently used, which is always an object of key/value pairs, with string keys and arbitrary values.
+
+While this is how everyone is using them, it became clear in code generation that the types weren't quite matching up to the expected usage. This should alleviate some extra checks on the implementer side.
+
+### Added
+
+- [**breaking**] Provide clearer schema for \_meta properties ([#290](https://github.com/agentclientprotocol/agent-client-protocol/pull/290))
+
 ## [0.8.0](https://github.com/agentclientprotocol/agent-client-protocol/compare/v0.7.0...v0.8.0) - 2025-11-28
 
 Some follow-up changes from 0.7.0. Most of the changes were in the Rust schema to make things a bit easier to work with.
diff --git a/Cargo.lock b/Cargo.lock
index 3253b45e..495717e1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4,7 +4,7 @@ version = 4
 
 [[package]]
 name = "agent-client-protocol-schema"
-version = "0.8.0"
+version = "0.9.0"
 dependencies = [
  "anyhow",
  "derive_more",
diff --git a/Cargo.toml b/Cargo.toml
index 736ac9b7..0c5e6ab3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "agent-client-protocol-schema"
 authors = ["Zed <hi@zed.dev>"]
-version = "0.8.0"
+version = "0.9.0"
 edition = "2024"
 license = "Apache-2.0"
 description = "A protocol for standardizing communication between code editors and AI coding agents"