update readme, changelog

Author: jonhealy1

CHANGELOG.md

@@ -18,6 +18,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Updated dynamic mapping for items to map long values to double versus float. [#326](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch/pull/326)
 - Extended Datetime Search to search on start_datetime and end_datetime as well as datetime fields. [#182](https://github.com/stac-utils/stac-fastapi-elasticsearch/pull/182)
 - Changed item update operation to use Elasticsearch index API instead of delete and create for better efficiency and atomicity. [#75](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch/issues/75)
+- Bulk insertion via `BulkTransactionsClient` now strictly validates all STAC Items using the Pydantic model before insertion. Any invalid item will immediately raise a `ValidationError`, ensuring consistent validation with single-item inserts and preventing invalid STAC Items from being stored. This validation is enforced regardless of the `RAISE_ON_BULK_ERROR` setting. [#368](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch/pull/368)
+
 
 ### Fixed
 

README.md

@@ -114,7 +114,7 @@ You can customize additional settings in your `.env` file:
 | `ELASTICSEARCH_VERSION`          | Version of Elasticsearch to use.                                                         | `8.11.0`                      | Optional                                                                                    |
 | `ENABLE_DIRECT_RESPONSE`         | Enable direct response for maximum performance (disables all FastAPI dependencies, including authentication, custom status codes, and validation) | `false`                  | Optional                                                                                    |
 | `OPENSEARCH_VERSION`         | OpenSearch version                                                                   | `2.11.1`                 | Optional       
-| `RAISE_ON_BULK_ERROR`         | Controls whether bulk insert operations raise exceptions on errors. If set to `true`, the operation will stop and raise an exception when an error occurs. If set to `false`, errors will be logged, and the operation will continue. | `false`                  | Optional                                                                                |
+| `RAISE_ON_BULK_ERROR`         | Controls whether bulk insert operations raise exceptions on errors. If set to `true`, the operation will stop and raise an exception when an error occurs. If set to `false`, errors will be logged, and the operation will continue. **Note:** STAC Item and ItemCollection validation errors will always raise, regardless of this flag. | `false`                  | Optional                                                                                |
 
 > [!NOTE]
 > The variables `ES_HOST`, `ES_PORT`, `ES_USE_SSL`, and `ES_VERIFY_CERTS` apply to both Elasticsearch and OpenSearch backends, so there is no need to rename the key names to `OS_` even if you're using OpenSearch.