diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 73cd417d1..ad3aa7c05 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,5 +1,5 @@
 {
-  "packages/toolbox-langchain": "0.6.0",
+  "packages/toolbox-langchain": "1.0.0",
   "packages/toolbox-core": "1.0.0",
   "packages/toolbox-llamaindex": "0.6.0",
   "packages/toolbox-adk": "1.0.0"
diff --git a/packages/toolbox-langchain/CHANGELOG.md b/packages/toolbox-langchain/CHANGELOG.md
index 91dae18e4..1ba381f54 100644
--- a/packages/toolbox-langchain/CHANGELOG.md
+++ b/packages/toolbox-langchain/CHANGELOG.md
@@ -1,5 +1,22 @@
 # Changelog
 
+## [1.0.0](https://github.com/googleapis/mcp-toolbox-sdk-python/compare/toolbox-langchain-v0.6.0...toolbox-langchain-v1.0.0) (2026-03-25)
+
+
+### Features
+
+* **core:** add observability with OpenTelemetry ([#583](https://github.com/googleapis/mcp-toolbox-sdk-python/issues/583)) ([d479385](https://github.com/googleapis/mcp-toolbox-sdk-python/commit/d479385cccf31a7cb1dffcc4634ddb6fe7ef932a))
+
+
+### Bug Fixes
+
+* **core:** resolve dropped default parameter values in MCP transport parsing ([#601](https://github.com/googleapis/mcp-toolbox-sdk-python/issues/601)) ([08c4af4](https://github.com/googleapis/mcp-toolbox-sdk-python/commit/08c4af4217feab19fdf8cb4fb328d1bb5e10a4e3))
+
+
+### Documentation
+
+* Migrate documentation to MCP Toolbox official docsite ([#581](https://github.com/googleapis/mcp-toolbox-sdk-python/issues/581)) ([da12899](https://github.com/googleapis/mcp-toolbox-sdk-python/commit/da1289944d8d401c0d2b958ae47da42da729848e))
+
 ## [0.6.0](https://github.com/googleapis/mcp-toolbox-sdk-python/compare/toolbox-langchain-v0.5.10...toolbox-langchain-v0.6.0) (2026-03-05)
 
 
diff --git a/packages/toolbox-langchain/src/toolbox_langchain/version.py b/packages/toolbox-langchain/src/toolbox_langchain/version.py
index 8f4814f32..756f75ffc 100644
--- a/packages/toolbox-langchain/src/toolbox_langchain/version.py
+++ b/packages/toolbox-langchain/src/toolbox_langchain/version.py
@@ -12,4 +12,4 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-__version__ = "0.6.0"
+__version__ = "1.0.0"