diff --git a/docs/next/api/herdr-api.schema.json b/docs/next/api/herdr-api.schema.json
index f9642ffa0d..8ff90f20de 100644
--- a/docs/next/api/herdr-api.schema.json
+++ b/docs/next/api/herdr-api.schema.json
@@ -1,6 +1,6 @@
 {
   "$schema": "https://json-schema.org/draft/2020-12/schema",
-  "protocol": 20,
+  "protocol": 21,
   "schema_version": 1,
   "schemas": {
     "error_response": {
@@ -4145,6 +4145,20 @@
           ],
           "type": "string"
         },
+        "WorkspaceCloseParams": {
+          "properties": {
+            "close_group": {
+              "type": "boolean"
+            },
+            "workspace_id": {
+              "type": "string"
+            }
+          },
+          "required": [
+            "workspace_id"
+          ],
+          "type": "object"
+        },
         "WorkspaceCreateParams": {
           "properties": {
             "cwd": {
@@ -4722,7 +4736,7 @@
               "type": "string"
             },
             "params": {
-              "$ref": "#/schemas/request/$defs/WorkspaceTarget"
+              "$ref": "#/schemas/request/$defs/WorkspaceCloseParams"
             }
           },
           "required": [
diff --git a/docs/next/website/src/content/docs/cli-reference.mdx b/docs/next/website/src/content/docs/cli-reference.mdx
index a0abc54118..87d89c1f36 100644
--- a/docs/next/website/src/content/docs/cli-reference.mdx
+++ b/docs/next/website/src/content/docs/cli-reference.mdx
@@ -121,7 +121,7 @@ herdr workspace get <workspace_id>
 herdr workspace focus <workspace_id>
 herdr workspace rename <workspace_id> <label>
 herdr workspace report-metadata <workspace_id> --source ID [--token NAME=VALUE] [--clear-token NAME] [--seq N] [--ttl-ms N]
-herdr workspace close <workspace_id>
+herdr workspace close <workspace_id> [--group]
 ```
 
 Create a workspace without stealing focus:
@@ -143,7 +143,7 @@ herdr worktree remove --workspace ID [--force]
 
 Worktrees are normal Herdr workspaces with Git checkout provenance. `worktree create` creates a Git worktree checkout, opens it as a workspace, and groups it with the parent repo workspace. If `--branch` names an existing local branch, Herdr checks it out; otherwise it creates the branch from `--base` or `HEAD`. Without `--path`, Herdr creates the checkout under `<worktrees.directory>/<repo>/<branch-slug>`.
 
-`workspace close` closes only Herdr state. To delete the checkout, run `worktree remove`. It runs `git worktree remove`, never deletes the branch, and requires `--force` when Git refuses a dirty checkout.
+`workspace close` closes only Herdr state. Closing a primary workspace while linked-worktree workspaces are open requires `--group`; without it, the command leaves the group open and returns `workspace_group_close_required`. To delete the checkout, run `worktree remove`. It runs `git worktree remove`, never deletes the branch, and requires `--force` when Git refuses a dirty checkout.
 
 ## Tabs
 
diff --git a/docs/next/website/src/content/docs/ja/cli-reference.mdx b/docs/next/website/src/content/docs/ja/cli-reference.mdx
index 9c14c6d678..7cf905bd11 100644
--- a/docs/next/website/src/content/docs/ja/cli-reference.mdx
+++ b/docs/next/website/src/content/docs/ja/cli-reference.mdx
@@ -117,7 +117,7 @@ herdr workspace get <workspace_id>
 herdr workspace focus <workspace_id>
 herdr workspace rename <workspace_id> <label>
 herdr workspace report-metadata <workspace_id> --source ID [--token NAME=VALUE] [--clear-token NAME] [--seq N] [--ttl-ms N]
-herdr workspace close <workspace_id>
+herdr workspace close <workspace_id> [--group]
 ```
 
 フォーカスを奪わずにワークスペースを作成します:
@@ -139,7 +139,7 @@ herdr worktree remove --workspace ID [--force]
 
 worktree は、Git チェックアウトの出自情報を持つ通常の Herdr ワークスペースです。`worktree create` は Git worktree のチェックアウトを作成し、ワークスペースとして開き、親リポジトリのワークスペースとグループ化します。`--branch` が既存のローカルブランチを指す場合はそれをチェックアウトし、そうでなければ `--base` または `HEAD` からブランチを作成します。`--path` がない場合、チェックアウトは `<worktrees.directory>/<repo>/<branch-slug>` の下に作成されます。
 
-`workspace close` は Herdr の状態だけを閉じます。`worktree remove` が明示的なチェックアウト削除の経路です。`git worktree remove` を実行し、ブランチは決して削除せず、Git がダーティなチェックアウトを拒否する場合は `--force` が必要です。
+`workspace close` は Herdr の状態だけを閉じます。リンクされた worktree ワークスペースが開いている間に親ワークスペースを閉じるには `--group` が必要です。指定しない場合、グループは開いたままになり `workspace_group_close_required` が返されます。`worktree remove` が明示的なチェックアウト削除の経路です。`git worktree remove` を実行し、ブランチは決して削除せず、Git がダーティなチェックアウトを拒否する場合は `--force` が必要です。
 
 ## タブ
 
diff --git a/docs/next/website/src/content/docs/ja/socket-api.mdx b/docs/next/website/src/content/docs/ja/socket-api.mdx
index 0dac2e13fd..5bb4fea7f0 100644
--- a/docs/next/website/src/content/docs/ja/socket-api.mdx
+++ b/docs/next/website/src/content/docs/ja/socket-api.mdx
@@ -299,6 +299,8 @@ Worktree メソッドは Git チェックアウトを Herdr ワークスペー
 
 worktree コマンドはライフサイクルイベントも発行します。`worktree.create` は `workspace.created`、`tab.created`、`pane.created`、`worktree.created` を発行します。`worktree.open` は `worktree.opened` を発行し、新しい Herdr ワークスペースを開いた場合はワークスペース/タブ/ペインの作成イベントも発行します。`worktree.remove` は `worktree.removed` を発行し、リンクされたワークスペースがまだ開いている場合は `workspace.closed` も発行します。
 
+リンクされた worktree ワークスペースが開いている親ワークスペースを `workspace.close` で閉じるには、params に `"close_group": true` が必要です。明示的なグループクローズ指定がない場合は `workspace_group_close_required` を返します。明示的なグループクローズは、閉じた各ワークスペースについて `workspace.closed` イベントを 1 件ずつ発行します。
+
 ## エージェントビューのクエリ
 
 `agent.view.set` は、組み込みの Agents ビューに一つの一時的な宣言型プロジェクションを
diff --git a/docs/next/website/src/content/docs/socket-api.mdx b/docs/next/website/src/content/docs/socket-api.mdx
index 0cae833e4f..8a055a3654 100644
--- a/docs/next/website/src/content/docs/socket-api.mdx
+++ b/docs/next/website/src/content/docs/socket-api.mdx
@@ -412,6 +412,8 @@ Use at most one of `workspace_id` or `cwd` for `worktree.list`, `worktree.create
 
 Worktree commands also emit lifecycle events. `worktree.create` emits `workspace.created`, `tab.created`, `pane.created`, and `worktree.created`. `worktree.open` emits `worktree.opened`, and it also emits workspace/tab/pane creation events when it opens a new Herdr workspace. `worktree.remove` emits `worktree.removed`; if the linked workspace is still open, it also emits `workspace.closed`.
 
+`workspace.close` rejects closing a primary workspace while linked-worktree workspaces are open unless its params include `"close_group": true`, returning `workspace_group_close_required` when explicit group intent is missing. An explicit group close emits one `workspace.closed` event for each workspace it closes.
+
 ## Agent view queries
 
 `agent.view.set` installs one transient declarative projection for the built-in
diff --git a/docs/next/website/src/content/docs/zh-cn/cli-reference.mdx b/docs/next/website/src/content/docs/zh-cn/cli-reference.mdx
index 496f4a6ac4..ade416ff74 100644
--- a/docs/next/website/src/content/docs/zh-cn/cli-reference.mdx
+++ b/docs/next/website/src/content/docs/zh-cn/cli-reference.mdx
@@ -117,7 +117,7 @@ herdr workspace get <workspace_id>
 herdr workspace focus <workspace_id>
 herdr workspace rename <workspace_id> <label>
 herdr workspace report-metadata <workspace_id> --source ID [--token NAME=VALUE] [--clear-token NAME] [--seq N] [--ttl-ms N]
-herdr workspace close <workspace_id>
+herdr workspace close <workspace_id> [--group]
 ```
 
 不抢占焦点地创建工作区:
@@ -139,7 +139,7 @@ herdr worktree remove --workspace ID [--force]
 
 worktree 是带有 Git 检出来源信息的普通 Herdr 工作区。`worktree create` 创建一个 Git worktree 检出,作为工作区打开,并与父仓库工作区分到一组。如果 `--branch` 指向已有的本地分支,Herdr 检出它;否则从 `--base` 或 `HEAD` 创建分支。没有 `--path` 时,Herdr 在 `<worktrees.directory>/<repo>/<branch-slug>` 下创建检出。
 
-`workspace close` 只关闭 Herdr 状态。`worktree remove` 是显式的检出删除路径;它运行 `git worktree remove`,从不删除分支,并在 Git 拒绝脏检出时要求 `--force`。
+`workspace close` 只关闭 Herdr 状态。当关联的 worktree 工作区仍然打开时，关闭父工作区需要 `--group`；否则命令会保留整个组并返回 `workspace_group_close_required`。`worktree remove` 是显式的检出删除路径;它运行 `git worktree remove`,从不删除分支,并在 Git 拒绝脏检出时要求 `--force`。
 
 ## 标签页
 
diff --git a/docs/next/website/src/content/docs/zh-cn/socket-api.mdx b/docs/next/website/src/content/docs/zh-cn/socket-api.mdx
index 6fb197f19d..ace5ba70fe 100644
--- a/docs/next/website/src/content/docs/zh-cn/socket-api.mdx
+++ b/docs/next/website/src/content/docs/zh-cn/socket-api.mdx
@@ -299,6 +299,8 @@ Worktree 方法把 Git 检出作为 Herdr 工作区管理。`worktree.create` 
 
 Worktree 命令也发出生命周期事件。`worktree.create` 发出 `workspace.created`、`tab.created`、`pane.created` 和 `worktree.created`。`worktree.open` 发出 `worktree.opened`,并在打开新的 Herdr 工作区时同时发出工作区/标签页/窗格创建事件。`worktree.remove` 发出 `worktree.removed`;如果关联的工作区仍然打开,还会发出 `workspace.closed`。
 
+当关联的 worktree 工作区仍然打开时，父工作区只有在 `workspace.close` 的 params 中包含 `"close_group": true` 时才会被关闭；缺少显式关闭组意图时会返回 `workspace_group_close_required`。显式关闭组时，每个被关闭的工作区都会发出一个 `workspace.closed` 事件。
+
 ## 智能体视图查询
 
 `agent.view.set` 为内置 Agents 视图设置一个临时的声明式投影。智能体信息或当前
diff --git a/src/api/schema.rs b/src/api/schema.rs
index 6f76e3d3d4..e06b701cc0 100644
--- a/src/api/schema.rs
+++ b/src/api/schema.rs
@@ -80,7 +80,7 @@ pub enum Method {
     #[serde(rename = "workspace.report_metadata")]
     WorkspaceReportMetadata(WorkspaceReportMetadataParams),
     #[serde(rename = "workspace.close")]
-    WorkspaceClose(WorkspaceTarget),
+    WorkspaceClose(WorkspaceCloseParams),
     #[serde(rename = "worktree.list")]
     WorktreeList(WorktreeListParams),
     #[serde(rename = "worktree.create")]
diff --git a/src/api/schema/tests.rs b/src/api/schema/tests.rs
index 5fe6dd27be..5199038dc1 100644
--- a/src/api/schema/tests.rs
+++ b/src/api/schema/tests.rs
@@ -61,6 +61,34 @@ fn request_uses_dot_method_names() {
     assert_eq!(json["method"], "workspace.create");
 }
 
+#[test]
+fn workspace_close_group_intent_defaults_false_and_round_trips() {
+    let request: Request = serde_json::from_value(serde_json::json!({
+        "id": "close",
+        "method": "workspace.close",
+        "params": { "workspace_id": "w1" }
+    }))
+    .unwrap();
+    assert!(matches!(
+        request.method,
+        Method::WorkspaceClose(WorkspaceCloseParams {
+            close_group: false,
+            ..
+        })
+    ));
+
+    let explicit = Request {
+        id: "close-group".into(),
+        method: Method::WorkspaceClose(WorkspaceCloseParams {
+            workspace_id: "w1".into(),
+            close_group: true,
+        }),
+    };
+    let json = serde_json::to_value(&explicit).unwrap();
+    assert_eq!(json["params"]["close_group"], true);
+    assert_eq!(serde_json::from_value::<Request>(json).unwrap(), explicit);
+}
+
 #[test]
 fn agent_start_and_prompt_requests_round_trip() {
     let start = Request {
diff --git a/src/api/schema/workspaces.rs b/src/api/schema/workspaces.rs
index f9ad4ced12..bfc6325244 100644
--- a/src/api/schema/workspaces.rs
+++ b/src/api/schema/workspaces.rs
@@ -16,6 +16,13 @@ pub struct WorkspaceCreateParams {
     pub env: HashMap<String, String>,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, schemars::JsonSchema)]
+pub struct WorkspaceCloseParams {
+    pub workspace_id: String,
+    #[serde(default, skip_serializing_if = "super::is_false")]
+    pub close_group: bool,
+}
+
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, schemars::JsonSchema)]
 pub struct WorkspaceRenameParams {
     pub workspace_id: String,
diff --git a/src/app/actions.rs b/src/app/actions.rs
index e3fc26391d..07f7278ba4 100644
--- a/src/app/actions.rs
+++ b/src/app/actions.rs
@@ -1677,24 +1677,7 @@ impl AppState {
         self.selection = None;
         self.selection_autoscroll = None;
         self.mark_session_dirty();
-        let close_indices = self
-            .workspaces
-            .get(self.selected)
-            .and_then(|ws| ws.worktree_space())
-            .filter(|space| !space.is_linked_worktree)
-            .map(|space| {
-                self.workspaces
-                    .iter()
-                    .enumerate()
-                    .filter_map(|(idx, ws)| {
-                        ws.worktree_space()
-                            .is_some_and(|member| member.key == space.key)
-                            .then_some(idx)
-                    })
-                    .collect::<Vec<_>>()
-            })
-            .filter(|indices| indices.len() >= 2)
-            .unwrap_or_else(|| vec![self.selected]);
+        let close_indices = self.workspace_close_indices(self.selected);
 
         let mut terminal_ids = Vec::new();
         let mut pane_ids = Vec::new();
@@ -1984,31 +1967,55 @@ impl AppState {
         self.apply_pane_zoom(ws_idx, pane_id, PaneZoomCommand::Toggle);
     }
 
-    pub(crate) fn workspace_close_would_close_worktree_group(&self, ws_idx: usize) -> bool {
+    pub(crate) fn workspace_close_indices(&self, ws_idx: usize) -> Vec<usize> {
         self.workspaces
             .get(ws_idx)
             .and_then(|ws| ws.worktree_space())
             .filter(|space| !space.is_linked_worktree)
-            .is_some_and(|space| {
+            .map(|space| {
                 self.workspaces
                     .iter()
-                    .filter(|ws| {
+                    .enumerate()
+                    .filter_map(|(idx, ws)| {
                         ws.worktree_space()
                             .is_some_and(|member| member.key == space.key)
+                            .then_some(idx)
                     })
-                    .count()
-                    >= 2
+                    .collect::<Vec<_>>()
             })
+            .filter(|indices| indices.len() >= 2)
+            .unwrap_or_else(|| vec![ws_idx])
+    }
+
+    pub(crate) fn workspace_close_would_close_worktree_group(&self, ws_idx: usize) -> bool {
+        self.workspace_close_indices(ws_idx).len() >= 2
+    }
+
+    pub(crate) fn begin_workspace_close_confirmation(&mut self, ws_idx: usize) -> bool {
+        let Some(workspace_id) = self
+            .workspaces
+            .get(ws_idx)
+            .map(|workspace| workspace.id.clone())
+        else {
+            return false;
+        };
+        self.selected = ws_idx;
+        self.confirm_close_workspace_id = Some(workspace_id);
+        self.mode = Mode::ConfirmClose;
+        true
+    }
+
+    pub(crate) fn take_confirmed_workspace_close_index(&mut self) -> Option<usize> {
+        let workspace_id = self.confirm_close_workspace_id.take()?;
+        self.workspaces
+            .iter()
+            .position(|workspace| workspace.id == workspace_id)
     }
 
     pub(crate) fn confirm_implicit_worktree_group_close(&mut self, ws_idx: usize) -> bool {
-        if self.confirm_close && self.workspace_close_would_close_worktree_group(ws_idx) {
-            self.selected = ws_idx;
-            self.mode = Mode::ConfirmClose;
-            true
-        } else {
-            false
-        }
+        self.confirm_close
+            && self.workspace_close_would_close_worktree_group(ws_idx)
+            && self.begin_workspace_close_confirmation(ws_idx)
     }
 
     #[cfg(test)]
diff --git a/src/app/api/workspaces.rs b/src/app/api/workspaces.rs
index cf50d3ad40..d9e689e374 100644
--- a/src/app/api/workspaces.rs
+++ b/src/app/api/workspaces.rs
@@ -1,8 +1,8 @@
 use std::path::PathBuf;
 
 use crate::api::schema::{
-    EventData, EventEnvelope, EventKind, ResponseResult, WorkspaceCreateParams,
-    WorkspaceMoveBlockParams, WorkspaceMoveParams, WorkspaceRenameParams,
+    EventData, EventEnvelope, EventKind, ResponseResult, WorkspaceCloseParams,
+    WorkspaceCreateParams, WorkspaceMoveBlockParams, WorkspaceMoveParams, WorkspaceRenameParams,
     WorkspaceReportMetadataParams, WorkspaceTarget,
 };
 use crate::app::App;
@@ -295,37 +295,46 @@ impl App {
         encode_success(id, ResponseResult::Ok {})
     }
 
-    pub(super) fn handle_workspace_close(&mut self, id: String, target: WorkspaceTarget) -> String {
-        let Some(index) = self.parse_workspace_id(&target.workspace_id) else {
-            return workspace_not_found(id, &target.workspace_id);
+    pub(super) fn handle_workspace_close(
+        &mut self,
+        id: String,
+        params: WorkspaceCloseParams,
+    ) -> String {
+        let Some(index) = self.parse_workspace_id(&params.workspace_id) else {
+            return workspace_not_found(id, &params.workspace_id);
         };
         if self.state.workspaces.get(index).is_none() {
-            return workspace_not_found(id, &target.workspace_id);
+            return workspace_not_found(id, &params.workspace_id);
         }
-        let workspace_id = self.public_workspace_id(index);
-        let workspace = self.workspace_info(index);
-        let pane_ids = self
-            .state
-            .workspaces
-            .get(index)
-            .map(|ws| {
-                ws.tabs
-                    .iter()
-                    .flat_map(|tab| tab.layout.pane_ids())
-                    .collect::<Vec<_>>()
+        let close_indices = self.state.workspace_close_indices(index);
+        if close_indices.len() >= 2 && !params.close_group {
+            return encode_error(
+                id,
+                "workspace_group_close_required",
+                "workspace has linked worktree workspaces; use --group (close_group=true in the API) to close the group",
+            );
+        }
+        let closed_workspaces = close_indices
+            .iter()
+            .map(|index| {
+                (
+                    self.public_workspace_id(*index),
+                    self.workspace_info(*index),
+                )
             })
-            .unwrap_or_default();
+            .collect::<Vec<_>>();
         self.state.selected = index;
         self.state.close_selected_workspace();
-        self.state.remove_plugin_pane_records(pane_ids);
         self.shutdown_detached_terminal_runtimes();
-        self.emit_event(EventEnvelope {
-            event: EventKind::WorkspaceClosed,
-            data: EventData::WorkspaceClosed {
-                workspace_id,
-                workspace: Some(workspace),
-            },
-        });
+        for (workspace_id, workspace) in closed_workspaces {
+            self.emit_event(EventEnvelope {
+                event: EventKind::WorkspaceClosed,
+                data: EventData::WorkspaceClosed {
+                    workspace_id,
+                    workspace: Some(workspace),
+                },
+            });
+        }
 
         encode_success(id, ResponseResult::Ok {})
     }
@@ -455,21 +464,149 @@ mod tests {
         app
     }
 
+    fn app_with_worktree_group() -> App {
+        let mut app = app_with_linked_worktree();
+        let mut parent = Workspace::test_new("parent");
+        parent.worktree_space = Some(crate::workspace::WorktreeSpaceMembership {
+            key: "repo-key".into(),
+            label: "herdr".into(),
+            repo_root: "/repo/herdr".into(),
+            checkout_path: "/repo/herdr".into(),
+            is_linked_worktree: false,
+        });
+        app.state.workspaces.insert(0, parent);
+        app.state.active = Some(1);
+        app.state.selected = 1;
+        app.state.mode = crate::app::Mode::Terminal;
+        app
+    }
+
+    #[test]
+    fn api_workspace_close_parent_group_requires_explicit_group_intent() {
+        for confirm_close in [true, false] {
+            let mut app = app_with_worktree_group();
+            app.state.confirm_close = confirm_close;
+            let parent_id = app.public_workspace_id(0);
+            let workspace_ids = app
+                .state
+                .workspaces
+                .iter()
+                .map(|workspace| workspace.id.clone())
+                .collect::<Vec<_>>();
+
+            let request: crate::api::schema::Request = serde_json::from_value(serde_json::json!({
+                "id": "req",
+                "method": "workspace.close",
+                "params": { "workspace_id": parent_id }
+            }))
+            .unwrap();
+            let response = app.handle_api_request(request);
+
+            let response: serde_json::Value = serde_json::from_str(&response).unwrap();
+            assert_eq!(response["error"]["code"], "workspace_group_close_required");
+            assert!(app.event_hub.events_after(0).is_empty());
+            assert_eq!(app.state.mode, crate::app::Mode::Terminal);
+            assert_eq!(app.state.active, Some(1));
+            assert_eq!(app.state.selected, 1);
+            assert_eq!(
+                app.state
+                    .workspaces
+                    .iter()
+                    .map(|workspace| workspace.id.clone())
+                    .collect::<Vec<_>>(),
+                workspace_ids
+            );
+        }
+    }
+
+    #[test]
+    fn api_workspace_close_noncontiguous_group_preserves_adversarial_identity_state() {
+        let mut app = app_with_worktree_group();
+        let parent = app.state.workspaces.remove(0);
+        let linked = app.state.workspaces.remove(0);
+        app.state = crate::app::state::AppState::test_with_adversarial_identity_state();
+        let survivor_id = app.state.workspaces[0].id.clone();
+        app.state.workspaces.insert(0, parent);
+        app.state.workspaces.push(linked);
+        app.state.active = Some(1);
+        app.state.selected = 1;
+        app.state.mode = crate::app::Mode::Terminal;
+        app.state.ensure_test_terminals();
+        let closed_pane_ids = [0, 2].map(|index| app.state.workspaces[index].tabs[0].root_pane);
+        let closed_terminal_ids = [0, 2].map(|index| {
+            app.state
+                .terminal_id_for_pane(index, app.state.workspaces[index].tabs[0].root_pane)
+                .expect("closed workspace pane has a terminal")
+        });
+        for pane_id in closed_pane_ids {
+            app.state.plugin_panes.insert(
+                pane_id,
+                crate::app::state::PluginPaneRecord {
+                    plugin_id: "example.pane".into(),
+                    entrypoint: "board".into(),
+                },
+            );
+        }
+        app.state.assert_invariants_for_test();
+
+        let parent_id = app.public_workspace_id(0);
+        let closed = [0, 2]
+            .into_iter()
+            .map(|index| (app.public_workspace_id(index), app.workspace_info(index)))
+            .collect::<Vec<_>>();
+
+        let response = app.handle_workspace_close(
+            "req".into(),
+            WorkspaceCloseParams {
+                workspace_id: parent_id,
+                close_group: true,
+            },
+        );
+
+        let success: SuccessResponse = serde_json::from_str(&response).unwrap();
+        assert_eq!(success.id, "req");
+        assert_eq!(app.state.workspaces.len(), 1);
+        assert_eq!(app.state.workspaces[0].id, survivor_id);
+        for terminal_id in closed_terminal_ids {
+            assert!(!app.state.terminals.contains_key(&terminal_id));
+        }
+        for pane_id in closed_pane_ids {
+            assert!(!app.state.plugin_panes.contains_key(&pane_id));
+        }
+        assert!(app.state.terminal_runtime_shutdowns.is_empty());
+        app.state.assert_invariants_for_test();
+        let events = app.event_hub.events_after(0);
+        assert_eq!(events.len(), closed.len());
+        for ((_, event), (workspace_id, workspace)) in events.iter().zip(closed) {
+            assert!(matches!(event.event, EventKind::WorkspaceClosed));
+            assert!(matches!(
+                &event.data,
+                EventData::WorkspaceClosed {
+                    workspace_id: closed_id,
+                    workspace: Some(closed_workspace),
+                } if closed_id == &workspace_id && closed_workspace == &workspace
+            ));
+        }
+    }
+
     #[test]
     fn api_workspace_close_closes_linked_worktree_workspace_only() {
-        let mut app = app_with_linked_worktree();
+        let mut app = app_with_worktree_group();
+        let linked_id = app.public_workspace_id(1);
 
         let response = app.handle_workspace_close(
             "req".into(),
-            WorkspaceTarget {
-                workspace_id: app.state.workspaces[0].id.clone(),
+            WorkspaceCloseParams {
+                workspace_id: linked_id,
+                close_group: true,
             },
         );
 
         let success: SuccessResponse = serde_json::from_str(&response).unwrap();
         assert_eq!(success.id, "req");
         assert_eq!(app.state.request_remove_linked_worktree, None);
-        assert!(app.state.workspaces.is_empty());
+        assert_eq!(app.state.workspaces.len(), 1);
+        assert_eq!(app.state.workspaces[0].display_name(), "parent");
     }
 
     #[test]
@@ -482,8 +619,9 @@ mod tests {
 
         let response = app.handle_workspace_close(
             "req".into(),
-            WorkspaceTarget {
+            WorkspaceCloseParams {
                 workspace_id: workspace_id.clone(),
+                close_group: false,
             },
         );
 
diff --git a/src/app/input/modal.rs b/src/app/input/modal.rs
index 343fa99c92..e710459b5c 100644
--- a/src/app/input/modal.rs
+++ b/src/app/input/modal.rs
@@ -733,12 +733,15 @@ pub(crate) fn handle_resize_key(state: &mut AppState, raw_key: TerminalKey) {
 }
 
 pub(super) fn open_confirm_close(state: &mut AppState) {
-    state.mode = Mode::ConfirmClose;
+    state.begin_workspace_close_confirmation(state.selected);
 }
 
 #[cfg(test)]
 pub(super) fn confirm_close_accept(state: &mut AppState) {
-    state.close_selected_workspace();
+    if let Some(ws_idx) = state.take_confirmed_workspace_close_index() {
+        state.selected = ws_idx;
+        state.close_selected_workspace();
+    }
     if state.workspaces.is_empty() {
         state.mode = Mode::Navigate;
     } else {
@@ -747,6 +750,7 @@ pub(super) fn confirm_close_accept(state: &mut AppState) {
 }
 
 pub(super) fn confirm_close_cancel(state: &mut AppState) {
+    state.confirm_close_workspace_id = None;
     state.mode = Mode::Navigate;
 }
 
@@ -1113,9 +1117,8 @@ impl App {
     }
 
     pub(super) fn confirm_close_accept_via_api(&mut self) {
-        let ws_idx = self.state.selected;
-        if ws_idx < self.state.workspaces.len() {
-            self.close_workspace_idx_via_api(ws_idx);
+        if let Some(ws_idx) = self.state.take_confirmed_workspace_close_index() {
+            self.close_workspace_idx_with_group_via_api(ws_idx);
         }
         self.state.mode = if self.state.active.is_some() {
             Mode::Terminal
@@ -1245,7 +1248,7 @@ impl App {
                 if self.state.confirm_close {
                     open_confirm_close(&mut self.state);
                 } else {
-                    self.close_workspace_idx_via_api(ws_idx);
+                    self.close_workspace_idx_with_group_via_api(ws_idx);
                     self.state.mode = Mode::Navigate;
                 }
             }
@@ -2139,8 +2142,8 @@ mod tests {
     #[test]
     fn confirm_close_keyboard_actions_are_direct_not_focused() {
         let mut state = state_with_workspaces(&["a", "b"]);
-        state.mode = Mode::ConfirmClose;
         state.selected = 1;
+        open_confirm_close(&mut state);
 
         handle_confirm_close_key(
             &mut state,
@@ -2149,7 +2152,7 @@ mod tests {
         assert_eq!(state.mode, Mode::Navigate);
         assert_eq!(state.workspaces.len(), 2);
 
-        state.mode = Mode::ConfirmClose;
+        open_confirm_close(&mut state);
         handle_confirm_close_key(
             &mut state,
             KeyEvent::new(KeyCode::Enter, KeyModifiers::empty()),
@@ -2160,7 +2163,6 @@ mod tests {
     #[test]
     fn confirm_close_for_linked_worktree_closes_workspace_only() {
         let mut state = state_with_workspaces(&["main", "issue"]);
-        state.mode = Mode::ConfirmClose;
         state.selected = 1;
         state.workspaces[1].worktree_space = Some(crate::workspace::WorktreeSpaceMembership {
             key: "repo-key".into(),
@@ -2170,6 +2172,7 @@ mod tests {
             is_linked_worktree: true,
         });
 
+        open_confirm_close(&mut state);
         handle_confirm_close_key(
             &mut state,
             KeyEvent::new(KeyCode::Enter, KeyModifiers::empty()),
@@ -2304,6 +2307,50 @@ mod tests {
         assert_eq!(state.workspaces.len(), 2);
     }
 
+    #[test]
+    fn api_confirm_close_accept_closes_parent_worktree_group() {
+        let mut app = app_with_test_workspaces(&["main", "issue"]);
+        mark_worktree_space_member(&mut app.state, 0, "repo-key");
+        mark_worktree_space_member(&mut app.state, 1, "repo-key");
+        app.state.selected = 0;
+        open_confirm_close(&mut app.state);
+
+        app.handle_confirm_close_key_via_api(KeyEvent::new(KeyCode::Enter, KeyModifiers::empty()));
+
+        assert!(app.state.workspaces.is_empty());
+        assert_eq!(app.state.mode, Mode::Navigate);
+        assert_eq!(app.event_hub.events_after(0).len(), 2);
+    }
+
+    #[test]
+    fn api_confirm_close_accept_keeps_the_original_workspace_target() {
+        let mut app = app_with_test_workspaces(&["main", "issue", "other"]);
+        mark_worktree_space_member(&mut app.state, 0, "repo-key");
+        mark_worktree_space_member(&mut app.state, 1, "repo-key");
+        app.state.selected = 0;
+        open_confirm_close(&mut app.state);
+
+        app.focus_workspace_idx_via_api(2);
+        assert_eq!(app.state.selected, 2);
+        assert_eq!(app.state.mode, Mode::ConfirmClose);
+
+        app.handle_confirm_close_key_via_api(KeyEvent::new(KeyCode::Enter, KeyModifiers::empty()));
+
+        assert_eq!(app.state.workspaces.len(), 1);
+        assert_eq!(app.state.workspaces[0].display_name(), "other");
+        assert_eq!(
+            app.event_hub
+                .events_after(0)
+                .iter()
+                .filter(|(_, event)| matches!(
+                    event.event,
+                    crate::api::schema::EventKind::WorkspaceClosed
+                ))
+                .count(),
+            2
+        );
+    }
+
     #[test]
     fn api_context_menu_close_tab_last_parent_group_workspace_keeps_confirmation_mode() {
         let mut app = app_with_test_workspaces(&["main", "issue"]);
diff --git a/src/app/input/mouse.rs b/src/app/input/mouse.rs
index 3c6c86f4fc..bf82126bee 100644
--- a/src/app/input/mouse.rs
+++ b/src/app/input/mouse.rs
@@ -3394,7 +3394,7 @@ mod tests {
         app.state.workspaces = vec![Workspace::test_new("a"), Workspace::test_new("b")];
         app.state.active = Some(0);
         app.state.selected = 1;
-        app.state.mode = Mode::ConfirmClose;
+        app.state.begin_workspace_close_confirmation(1);
 
         let popup = app.state.confirm_close_rect();
         let inner = Rect::new(
diff --git a/src/app/input/navigate.rs b/src/app/input/navigate.rs
index 8e3d7d6eef..517e267d01 100644
--- a/src/app/input/navigate.rs
+++ b/src/app/input/navigate.rs
@@ -214,7 +214,7 @@ impl App {
                     if self.state.confirm_close {
                         super::modal::open_confirm_close(&mut self.state);
                     } else {
-                        self.close_workspace_idx_via_api(ws_idx);
+                        self.close_workspace_idx_with_group_via_api(ws_idx);
                         leave_navigate_mode(&mut self.state);
                     }
                 }
@@ -443,9 +443,9 @@ impl App {
         self.runtime_workspace_focus("tui.workspace.focus", workspace_id);
     }
 
-    pub(crate) fn close_workspace_idx_via_api(&mut self, ws_idx: usize) {
+    pub(crate) fn close_workspace_idx_with_group_via_api(&mut self, ws_idx: usize) {
         let workspace_id = self.public_workspace_id(ws_idx);
-        self.runtime_workspace_close("tui.workspace.close", workspace_id);
+        self.runtime_workspace_close_group("tui.workspace.close", workspace_id);
     }
 
     pub(crate) fn move_workspace_via_api(&mut self, source_ws_idx: usize, insert_idx: usize) {
@@ -489,7 +489,7 @@ impl App {
             if self.state.confirm_implicit_worktree_group_close(ws_idx) {
                 return true;
             }
-            self.close_workspace_idx_via_api(ws_idx);
+            self.close_workspace_idx_with_group_via_api(ws_idx);
             return false;
         }
         let tab_idx = self.state.workspaces[ws_idx].active_tab_index();
@@ -3517,6 +3517,23 @@ navigate_pane_down = "ctrl+j"
         assert_eq!(state.mode, Mode::Terminal);
     }
 
+    #[test]
+    fn tui_close_parent_group_closes_immediately_when_confirmation_disabled() {
+        let mut app = app_with_test_workspaces(&["main", "issue"]);
+        mark_worktree_space_member(&mut app.state, 0, "repo-key");
+        mark_worktree_space_member(&mut app.state, 1, "repo-key");
+        app.state.active = Some(0);
+        app.state.selected = 0;
+        app.state.mode = Mode::Navigate;
+        app.state.confirm_close = false;
+
+        app.execute_tui_navigate_action(NavigateAction::CloseWorkspace, ActionContext::Navigate);
+
+        assert!(app.state.workspaces.is_empty());
+        assert_eq!(app.state.mode, Mode::Navigate);
+        assert_eq!(app.event_hub.events_after(0).len(), 2);
+    }
+
     #[test]
     fn prefix_close_pane_last_parent_group_pane_opens_confirmation() {
         let mut state = state_with_workspaces(&["main", "issue"]);
diff --git a/src/app/mod.rs b/src/app/mod.rs
index ff286c3f18..c28f62da1e 100644
--- a/src/app/mod.rs
+++ b/src/app/mod.rs
@@ -718,6 +718,7 @@ impl App {
             host_mouse_pixels: None,
             session_dirty: false,
             terminal_runtime_shutdowns: Vec::new(),
+            confirm_close_workspace_id: None,
         };
 
         state.terminals = restored_terminals;
diff --git a/src/app/runtime_mutations.rs b/src/app/runtime_mutations.rs
index e9b3fde14c..d3d767e76a 100644
--- a/src/app/runtime_mutations.rs
+++ b/src/app/runtime_mutations.rs
@@ -2,8 +2,9 @@ use crate::api::schema::{
     EmptyParams, LayoutSetSplitRatioParams, Method, PaneFocusDirectionParams, PaneInputSetParams,
     PaneRenameParams, PaneResizeParams, PaneSplitParams, PaneSwapParams, PaneTarget,
     PaneZoomParams, TabCreateParams, TabMoveParams, TabRenameParams, TabTarget,
-    WorkspaceCreateParams, WorkspaceMoveBlockParams, WorkspaceMoveParams, WorkspaceRenameParams,
-    WorkspaceTarget, WorktreeCreateParams, WorktreeOpenParams, WorktreeRemoveParams,
+    WorkspaceCloseParams, WorkspaceCreateParams, WorkspaceMoveBlockParams, WorkspaceMoveParams,
+    WorkspaceRenameParams, WorkspaceTarget, WorktreeCreateParams, WorktreeOpenParams,
+    WorktreeRemoveParams,
 };
 
 use super::App;
@@ -61,12 +62,18 @@ impl App {
         self.dispatch_runtime_mutation(id, Method::WorkspaceMoveBlock(params))
     }
 
-    pub(crate) fn runtime_workspace_close(
+    pub(crate) fn runtime_workspace_close_group(
         &mut self,
         id: &'static str,
         workspace_id: String,
     ) -> String {
-        self.dispatch_runtime_mutation(id, Method::WorkspaceClose(WorkspaceTarget { workspace_id }))
+        self.dispatch_runtime_mutation(
+            id,
+            Method::WorkspaceClose(WorkspaceCloseParams {
+                workspace_id,
+                close_group: true,
+            }),
+        )
     }
 
     pub(crate) fn runtime_tab_create(
diff --git a/src/app/state.rs b/src/app/state.rs
index 21ee889902..782b8ae5f9 100644
--- a/src/app/state.rs
+++ b/src/app/state.rs
@@ -1445,6 +1445,8 @@ pub struct AppState {
     pub(crate) previous_pane_focus: Option<PaneFocusTarget>,
     pub selected: usize,
     pub mode: Mode,
+    /// Stable workspace identity captured when the close confirmation opens.
+    pub(crate) confirm_close_workspace_id: Option<String>,
     pub should_quit: bool,
     /// In monolithic --no-session mode, detach exits the app because there is no server to detach from.
     pub detach_exits: bool,
@@ -1836,6 +1838,7 @@ impl AppState {
             previous_pane_focus: None,
             selected: 0,
             mode: Mode::Navigate,
+            confirm_close_workspace_id: None,
             should_quit: false,
             detach_exits: false,
             detach_requested: false,
diff --git a/src/cli/runtime.rs b/src/cli/runtime.rs
index 16d2d8b3ab..793ca24ee1 100644
--- a/src/cli/runtime.rs
+++ b/src/cli/runtime.rs
@@ -2,8 +2,8 @@ use crate::api::schema::{
     EmptyParams, Method, PaneFocusDirectionParams, PaneInputSetParams, PaneMoveParams,
     PaneRenameParams, PaneResizeParams, PaneSplitParams, PaneSwapParams, PaneTarget,
     PaneZoomParams, Request, TabCreateParams, TabListParams, TabRenameParams, TabTarget,
-    WorkspaceCreateParams, WorkspaceRenameParams, WorkspaceTarget, WorktreeCreateParams,
-    WorktreeListParams, WorktreeOpenParams, WorktreeRemoveParams,
+    WorkspaceCloseParams, WorkspaceCreateParams, WorkspaceRenameParams, WorkspaceTarget,
+    WorktreeCreateParams, WorktreeListParams, WorktreeOpenParams, WorktreeRemoveParams,
 };
 
 fn print_method_response(id: &'static str, method: Method) -> std::io::Result<i32> {
@@ -42,11 +42,8 @@ pub(super) fn workspace_rename(params: WorkspaceRenameParams) -> std::io::Result
     print_method_response("cli:workspace:rename", Method::WorkspaceRename(params))
 }
 
-pub(super) fn workspace_close(workspace_id: String) -> std::io::Result<i32> {
-    print_method_response(
-        "cli:workspace:close",
-        Method::WorkspaceClose(WorkspaceTarget { workspace_id }),
-    )
+pub(super) fn workspace_close(params: WorkspaceCloseParams) -> std::io::Result<i32> {
+    print_method_response("cli:workspace:close", Method::WorkspaceClose(params))
 }
 
 pub(super) fn tab_list(params: TabListParams) -> std::io::Result<i32> {
diff --git a/src/cli/workspace.rs b/src/cli/workspace.rs
index 525fc971c5..c24c9b7390 100644
--- a/src/cli/workspace.rs
+++ b/src/cli/workspace.rs
@@ -225,16 +225,19 @@ fn workspace_report_metadata(args: &[String]) -> std::io::Result<i32> {
 }
 
 fn workspace_close(args: &[String]) -> std::io::Result<i32> {
-    let Some(raw_workspace_id) = args.first() else {
-        eprintln!("usage: herdr workspace close <workspace_id>");
-        return Ok(2);
+    let (raw_workspace_id, close_group) = match args {
+        [workspace_id] => (workspace_id, false),
+        [workspace_id, flag] if flag == "--group" => (workspace_id, true),
+        _ => {
+            eprintln!("usage: herdr workspace close <workspace_id> [--group]");
+            return Ok(2);
+        }
     };
-    if args.len() != 1 {
-        eprintln!("usage: herdr workspace close <workspace_id>");
-        return Ok(2);
-    }
 
-    super::runtime::workspace_close(super::normalize_workspace_id(raw_workspace_id))
+    super::runtime::workspace_close(crate::api::schema::WorkspaceCloseParams {
+        workspace_id: super::normalize_workspace_id(raw_workspace_id),
+        close_group,
+    })
 }
 
 fn print_workspace_help() {
@@ -245,5 +248,5 @@ fn print_workspace_help() {
     eprintln!("  herdr workspace focus <workspace_id>");
     eprintln!("  herdr workspace rename <workspace_id> <label>");
     eprintln!("  herdr workspace report-metadata <workspace_id> --source ID [--token NAME=VALUE] [--clear-token NAME] [--seq N] [--ttl-ms N]");
-    eprintln!("  herdr workspace close <workspace_id>");
+    eprintln!("  herdr workspace close <workspace_id> [--group]");
 }
diff --git a/src/protocol/wire.rs b/src/protocol/wire.rs
index 4a445361f5..3680a5576c 100644
--- a/src/protocol/wire.rs
+++ b/src/protocol/wire.rs
@@ -13,7 +13,7 @@ use serde::{Deserialize, Serialize};
 // ---------------------------------------------------------------------------
 
 /// Current protocol version. Bumped when wire format changes incompatibly.
-pub const PROTOCOL_VERSION: u32 = 20;
+pub const PROTOCOL_VERSION: u32 = 21;
 
 /// Maximum allowed frame payload size (2 MB). Frames larger than this are
 /// rejected to prevent denial-of-service via oversized length prefixes.
diff --git a/tests/api_ping.rs b/tests/api_ping.rs
index 917eb2d90a..d6b253fbf0 100644
--- a/tests/api_ping.rs
+++ b/tests/api_ping.rs
@@ -304,7 +304,7 @@ fn ping_over_socket_returns_version() {
     assert_eq!(value["result"]["version"], env!("CARGO_PKG_VERSION"));
     // Intentionally hardcoded so wire protocol bumps require updating this test.
     // Changing this value means old clients/servers are no longer compatible.
-    assert_eq!(value["result"]["protocol"], 20);
+    assert_eq!(value["result"]["protocol"], 21);
 
     cleanup_spawned_herdr(child, base);
 }
diff --git a/tests/cli/sessions.rs b/tests/cli/sessions.rs
index d86de44a65..1f7e3c0b8b 100644
--- a/tests/cli/sessions.rs
+++ b/tests/cli/sessions.rs
@@ -389,7 +389,7 @@ fn status_commands_report_client_and_server_versions() {
         "stdout: {full_stdout}"
     );
     assert!(
-        full_stdout.contains("  protocol: 20"),
+        full_stdout.contains("  protocol: 21"),
         "stdout: {full_stdout}"
     );
     assert!(full_stdout.contains("server:\n"), "stdout: {full_stdout}");
@@ -422,7 +422,7 @@ fn status_commands_report_client_and_server_versions() {
         "stdout: {server_stdout}"
     );
     assert!(
-        server_stdout.contains("protocol: 20"),
+        server_stdout.contains("protocol: 21"),
         "stdout: {server_stdout}"
     );
 
@@ -434,7 +434,7 @@ fn status_commands_report_client_and_server_versions() {
         "stdout: {client_stdout}"
     );
     assert!(
-        client_stdout.contains("protocol: 20"),
+        client_stdout.contains("protocol: 21"),
         "stdout: {client_stdout}"
     );
     assert!(
@@ -444,7 +444,7 @@ fn status_commands_report_client_and_server_versions() {
 
     let full_json = run_cli_json(&socket_path, &["status", "--json"]);
     assert_eq!(full_json["client"]["version"], env!("CARGO_PKG_VERSION"));
-    assert_eq!(full_json["client"]["protocol"], 20);
+    assert_eq!(full_json["client"]["protocol"], 21);
     assert_eq!(full_json["server"]["status"], "running");
     assert_eq!(full_json["server"]["running"], true);
     assert_eq!(full_json["server"]["compatible"], true);
@@ -458,12 +458,12 @@ fn status_commands_report_client_and_server_versions() {
     let server_json = run_cli_json(&socket_path, &["status", "server", "--json"]);
     assert_eq!(server_json["status"], "running");
     assert_eq!(server_json["version"], env!("CARGO_PKG_VERSION"));
-    assert_eq!(server_json["protocol"], 20);
+    assert_eq!(server_json["protocol"], 21);
     assert_eq!(server_json["compatible"], true);
 
     let client_json = run_cli_json(&socket_path, &["status", "client", "--json"]);
     assert_eq!(client_json["version"], env!("CARGO_PKG_VERSION"));
-    assert_eq!(client_json["protocol"], 20);
+    assert_eq!(client_json["protocol"], 21);
     assert!(client_json["binary"]
         .as_str()
         .is_some_and(|path| !path.is_empty()));
diff --git a/tests/cli/workspace.rs b/tests/cli/workspace.rs
index 4153f3b240..afa47c66d4 100644
--- a/tests/cli/workspace.rs
+++ b/tests/cli/workspace.rs
@@ -216,6 +216,83 @@ fn worktree_management_commands_work() {
     cleanup_spawned_herdr(herdr, base);
 }
 
+#[test]
+fn workspace_close_requires_explicit_worktree_group_intent() {
+    let base = unique_test_dir();
+    let config_home = base.join("config");
+    let runtime_dir = base.join("runtime");
+    let socket_path = runtime_dir.join("herdr.sock");
+    let repo = base.join("repo");
+    let checkout = base.join("checkout");
+    create_committed_repo(&repo);
+
+    let herdr = spawn_herdr(&config_home, &runtime_dir, &socket_path);
+    wait_for_socket(&socket_path, Duration::from_secs(5));
+
+    let created = run_cli_json(
+        &socket_path,
+        &[
+            "worktree",
+            "create",
+            "--cwd",
+            repo.to_str().unwrap(),
+            "--branch",
+            "worktree/group-close",
+            "--path",
+            checkout.to_str().unwrap(),
+        ],
+    );
+    assert_eq!(created["result"]["type"], "worktree_created");
+    let workspaces = run_cli_json(&socket_path, &["workspace", "list"]);
+    let workspace_list = workspaces["result"]["workspaces"].as_array().unwrap();
+    let parent_workspace_id = workspace_list
+        .iter()
+        .find(|workspace| workspace["worktree"]["is_linked_worktree"] == false)
+        .and_then(|workspace| workspace["workspace_id"].as_str())
+        .unwrap()
+        .to_string();
+    let workspace_ids = workspace_list
+        .iter()
+        .map(|workspace| workspace["workspace_id"].as_str().unwrap().to_string())
+        .collect::<Vec<_>>();
+
+    let rejected = run_cli(&socket_path, &["workspace", "close", &parent_workspace_id]);
+    assert_eq!(rejected.status.code(), Some(1));
+    let error: serde_json::Value = serde_json::from_slice(&rejected.stderr).unwrap();
+    assert_eq!(error["error"]["code"], "workspace_group_close_required");
+    let after_rejection = run_cli_json(&socket_path, &["workspace", "list"]);
+    assert_eq!(
+        after_rejection["result"]["workspaces"]
+            .as_array()
+            .unwrap()
+            .iter()
+            .map(|workspace| workspace["workspace_id"].as_str().unwrap().to_string())
+            .collect::<Vec<_>>(),
+        workspace_ids
+    );
+
+    let closed = run_cli(
+        &socket_path,
+        &["workspace", "close", &parent_workspace_id, "--group"],
+    );
+    assert!(
+        closed.status.success(),
+        "stderr: {}",
+        String::from_utf8_lossy(&closed.stderr)
+    );
+    let after_close = run_cli_json(&socket_path, &["workspace", "list"]);
+    assert!(after_close["result"]["workspaces"]
+        .as_array()
+        .unwrap()
+        .is_empty());
+    assert!(
+        checkout.exists(),
+        "workspace close must not remove the checkout"
+    );
+
+    cleanup_spawned_herdr(herdr, base);
+}
+
 #[test]
 fn forced_worktree_remove_terminates_processes_inside_checkout() {
     let base = unique_test_dir();
diff --git a/tests/support/mod.rs b/tests/support/mod.rs
index f0ed100bcc..f295dbbe71 100644
--- a/tests/support/mod.rs
+++ b/tests/support/mod.rs
@@ -15,7 +15,7 @@ static INIT: Once = Once::new();
 static CLEANUP_GUARD: OnceLock<CleanupGuard> = OnceLock::new();
 const WATCHDOG_SCAN_INTERVAL: Duration = Duration::from_secs(1);
 const RUNTIME_OWNER_MARKER: &str = ".herdr-test-owner-pid";
-pub const CURRENT_PROTOCOL: u32 = 20;
+pub const CURRENT_PROTOCOL: u32 = 21;
 
 pub fn register_spawned_herdr_pid(pid: Option<u32>) {
     let Some(pid) = pid else {