diff --git a/crates/worker/src/feature/builtin/manage_workdir.rs b/crates/worker/src/feature/builtin/manage_workdir.rs
index 69f22d9b..677a7721 100644
--- a/crates/worker/src/feature/builtin/manage_workdir.rs
+++ b/crates/worker/src/feature/builtin/manage_workdir.rs
@@ -21,6 +21,8 @@ use workdir::{
 };
 
 use workspace_api::{
+    WorkingDirectoryCreateRequest as WorkdirCreateRequest,
+    WorkingDirectoryCreateResponse as WorkdirCreateResponse,
     WorkingDirectoryDetailResponse as WorkdirDetailResponse,
     WorkingDirectoryListResponse as WorkdirListResponse,
 };
@@ -421,9 +423,9 @@ impl WorkspaceHttpWorkdirBackend {
             runtime_id: runtime_id.map(str::to_string),
             repository_id: repository_id.to_string(),
             selector,
-            operation_id,
+            operation_id: Some(operation_id),
         };
-        let response = self.execute_json::<WorkdirDetailResponse>(WorkspaceRequest::json(
+        let response = self.execute_json::<WorkdirCreateResponse>(WorkspaceRequest::json(
             WorkspaceRequestMethod::Post,
             format!("/api/w/{workspace_id}/working-directories"),
             serde_json::to_string(&request).map_err(decode_error)?,
@@ -702,16 +704,6 @@ struct WorkdirCreateInput {
     selector: Option<String>,
 }
 
-#[derive(Debug, Serialize)]
-struct WorkdirCreateRequest {
-    #[serde(skip_serializing_if = "Option::is_none")]
-    runtime_id: Option<String>,
-    repository_id: String,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    selector: Option<String>,
-    operation_id: String,
-}
-
 #[derive(Debug, Deserialize)]
 #[serde(deny_unknown_fields)]
 struct WorkdirAttachInput {
diff --git a/crates/workspace-api/src/lib.rs b/crates/workspace-api/src/lib.rs
index 8170db95..37b33cf5 100644
--- a/crates/workspace-api/src/lib.rs
+++ b/crates/workspace-api/src/lib.rs
@@ -209,12 +209,12 @@ pub struct WorkingDirectorySummary {
 #[cfg_attr(feature = "typescript", ts(optional_fields = nullable))]
 #[serde(deny_unknown_fields)]
 pub struct WorkingDirectoryCreateRequest {
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub runtime_id: Option<String>,
     pub repository_id: String,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub selector: Option<String>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub operation_id: Option<String>,
 }
 
@@ -765,6 +765,9 @@ mod tests {
         assert_eq!(request.runtime_id, None);
         assert_eq!(request.selector, None);
         assert_eq!(request.operation_id, None);
+
+        let serialized = serde_json::to_value(request).expect("serialize create request");
+        assert_eq!(serialized, serde_json::json!({"repository_id": "main"}));
     }
 
     #[test]