diff --git a/_api-reference/index-apis/force-merge.md b/_api-reference/index-apis/force-merge.md
index 6ad2e7f23c..6c2a61bef3 100644
--- a/_api-reference/index-apis/force-merge.md
+++ b/_api-reference/index-apis/force-merge.md
@@ -72,6 +72,7 @@ The following table lists the available query parameters. All query parameters a
 | `ignore_unavailable` | Boolean | If `true`, OpenSearch ignores missing or closed indexes. If `false`, OpenSearch returns an error if the force merge operation encounters missing or closed indexes. Default is `false`. |
 | `max_num_segments` | Integer | The number of larger segments into which smaller segments are merged. Set this parameter to `1` to merge all segments into one segment. The default behavior is to perform the merge as necessary. |
 | `only_expunge_deletes` | Boolean | If `true`, the merge operation only expunges segments containing a certain percentage of deleted documents. The percentage is 10% by default and is configurable in the `index.merge.policy.expunge_deletes_allowed` setting. Prior to OpenSearch 2.12, `only_expunge_deletes` ignored the `index.merge.policy.max_merged_segment` setting. Starting with OpenSearch 2.12, using `only_expunge_deletes` does not produce segments larger than `index.merge.policy.max_merged_segment` (by default, 5 GB). For more information, see [Deleted documents](#deleted-documents). Default is `false`. |
+| `primary_only` | Boolean | If set to `true`, then the merge operation is performed only on the primary shards of an index. This can be useful when you want to take a snapshot of the index after the merge is complete. Snapshots only copy segments from the primary shards. Merging the primary shards can reduce resource consumption. Default is `false`. |
 
 #### Example request: Force merge a specific index
 
@@ -101,6 +102,13 @@ POST /.testindex-logs/_forcemerge?max_num_segments=1
 ```
 {% include copy-curl.html %}
 
+#### Example request: Force merge primary shards
+
+```json
+POST /.testindex-logs/_forcemerge?primary_only=true
+```
+{% include copy-curl.html %}
+
 #### Example response
 
 ```json