diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 5de742c..e08e658 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,6 +1,6 @@
 {
   "packages/sandbox": "0.4.52",
-  "packages/agent": "0.12.27",
+  "packages/agent": "0.12.28",
   "packages/provider": "0.4.49",
   "packages/effect": "0.0.0"
 }
diff --git a/packages/agent/CHANGELOG.md b/packages/agent/CHANGELOG.md
index ff70bbf..ce5f756 100644
--- a/packages/agent/CHANGELOG.md
+++ b/packages/agent/CHANGELOG.md
@@ -1,5 +1,17 @@
 # Changelog
 
+## [0.12.28](https://github.com/coder/ai-sdk/compare/agent-v0.12.27...agent-v0.12.28) (2026-10-29)
+
+Tool outputs are now flattened to text for chatd, improving compatibility with how tool results are consumed.
+
+### Highlights
+
+- Content tool outputs are now flattened to plain text for chatd. ([#405](https://github.com/coder/ai-sdk/pull/405))
+
+### Bug Fixes
+
+* **agent:** flatten content tool outputs to text for chatd ([#405](https://github.com/coder/ai-sdk/issues/405)) ([7edc552](https://github.com/coder/ai-sdk/commit/7edc55252aa893fe8aa49711e945e6e82a5193f2))
+
 ## [0.12.27](https://github.com/coder/ai-sdk/compare/agent-v0.12.26...agent-v0.12.27) (2026-10-28)
 
 A maintenance release with internal changes and no documented user-facing updates.
diff --git a/packages/agent/package.json b/packages/agent/package.json
index 1ac54f7..d735d35 100644
--- a/packages/agent/package.json
+++ b/packages/agent/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@coder/ai-sdk-agent",
-  "version": "0.12.27",
+  "version": "0.12.28",
   "description": "A Vercel AI SDK-compliant agent backed by Coder Agents, Coder's server-side agent runtime. `new CoderAgent()` returns a real AI SDK Agent (generate/stream).",
   "keywords": [
     "agent",