diff --git a/crates/cyber-tools/tests/worktree_setup.rs b/crates/cyber-tools/tests/worktree_setup.rs
index cceb3887..942659bd 100644
--- a/crates/cyber-tools/tests/worktree_setup.rs
+++ b/crates/cyber-tools/tests/worktree_setup.rs
@@ -2690,6 +2690,104 @@ async fn cwd_changed_idle_exit_is_committed_once_and_replay_is_silent() {
     assert_eq!(cwd_history(&flow, &id), before);
 }
 
+#[cfg(unix)]
+#[tokio::test]
+async fn cwd_changed_failed_idle_exit_commit_is_silent_and_retry_commits_once() {
+    use std::sync::atomic::{AtomicBool, Ordering};
+    use support::flow::{call, text};
+
+    let flow = worktree_flow(vec![
+        call("enter", "enter_worktree", json!({"name":"failed-cwd-exit"})),
+        text("done"),
+    ]);
+    let recorder = CwdRecorder::start(false).await;
+    recorder.attach(&flow);
+    let id = flow.session("default").await;
+    flow.prompt(&id, "enter and finish").await;
+    flow.settle_within(&id, Duration::from_secs(60)).await;
+    let entered = recorder.events();
+    assert_eq!(entered.len(), 1);
+    assert_cwd_transition(&flow, &id, &entered[0]);
+    let directory = flow.runtime.state(&id).await.unwrap().info.directory;
+    assert_ne!(directory, flow.f.repo.display().to_string());
+
+    let attempted = Arc::new(AtomicBool::new(false));
+    let observed = Arc::clone(&attempted);
+    let session = id.clone();
+    flow.f
+        .store
+        .set_append_fault(Some(Arc::new(move |owner, event| {
+            let refuse = owner == session && event.kind == "session.worktree.exited.1";
+            if refuse {
+                observed.store(true, Ordering::SeqCst);
+            }
+            refuse
+        })));
+    let failed = tokio::time::timeout(
+        Duration::from_secs(30),
+        flow.runtime.exit_idle_worktree(&id),
+    )
+    .await;
+    flow.f.store.set_append_fault(None);
+    let error = failed.expect("failed commit settles").unwrap_err();
+    assert!(attempted.load(Ordering::SeqCst));
+    assert!(
+        error.to_string().contains("injected append fault"),
+        "{error}"
+    );
+    assert_eq!(
+        flow.runtime.state(&id).await.unwrap().info.directory,
+        directory
+    );
+    assert_eq!(
+        recorder.events(),
+        entered,
+        "a failed commit emits no CwdChanged"
+    );
+    assert!(
+        cwd_history(&flow, &id)
+            .iter()
+            .all(|event| event.kind != "session.worktree.exited.1")
+    );
+
+    tokio::time::timeout(
+        Duration::from_secs(30),
+        flow.runtime.exit_idle_worktree(&id),
+    )
+    .await
+    .expect("retry settles")
+    .unwrap()
+    .expect("retry commits the idle exit");
+    assert_eq!(
+        flow.runtime.state(&id).await.unwrap().info.directory,
+        flow.f.repo.display().to_string()
+    );
+    let events = recorder.events();
+    assert_eq!(events.len(), 2, "{events:?}");
+    assert_cwd_transition(&flow, &id, &events[1]);
+    assert_eq!(events[1]["transition"], "session.worktree.exited.1");
+    assert_eq!(events[1]["previous_directory"], directory);
+    assert_eq!(
+        cwd_history(&flow, &id)
+            .iter()
+            .filter(|event| event.kind == "session.worktree.exited.1")
+            .count(),
+        1
+    );
+    assert!(
+        flow.runtime
+            .exit_idle_worktree(&id)
+            .await
+            .unwrap()
+            .is_none()
+    );
+    assert_eq!(
+        recorder.events(),
+        events,
+        "an already exited Session is silent"
+    );
+}
+
 #[cfg(unix)]
 #[tokio::test]
 async fn cwd_changed_does_not_observe_permission_refusal() {
diff --git a/openspec/changes/complete-plugin-hook-runtime/tasks.md b/openspec/changes/complete-plugin-hook-runtime/tasks.md
index f4428033..6c5bd4b3 100644
--- a/openspec/changes/complete-plugin-hook-runtime/tasks.md
+++ b/openspec/changes/complete-plugin-hook-runtime/tasks.md
@@ -80,6 +80,16 @@ required; this correction does not close tasks 2.1–2.4.
 - [ ] 5.2 Implement bounded `FileChanged` observation/reconciliation for tools, formatters, shell/background and external edits, including overflow and self-write loop prevention. Verify alias-aware Session admission and resource/lifecycle behavior before closing this task. See [file-observation-implementation.md](file-observation-implementation.md) for implementation and verification evidence.
 - [ ] 5.3 Test no false post-effect success for refused/failed/unknown transitions, pre-effect WorktreeCreate veto/no Git mutation, stable event identity, correct scope/order, rename/delete, multiple Sessions, shutdown/restart and unknown handler outcomes.
 
+The CwdChanged regression
+`cwd_changed_failed_idle_exit_commit_is_silent_and_retry_commits_once` in
+`crates/cyber-tools/tests/worktree_setup.rs` exercises a real failed idle-exit
+append and HTTP hook delivery. It verifies that the fault was reached, the
+Location stays unchanged, and no durable exit or CwdChanged appears. After the
+fault is cleared, retry commits one exit with the matching hook identity; another
+exit is silent. The exact case passes locally on macOS. This is a known
+before-append failure, not proof of an unknown commit outcome. The test is
+Unix-only and hosted acceptance remains required; task 5.3 stays open.
+
 Task 5.2 is in progress. The full focused suite at `3e852288` passed Linux/macOS/Windows. At `c0cc40e3`, complete Linux/Windows jobs also passed all 18 HTTP/runtime scenarios, including idle-return ownership, archive/resume and native burst recovery; macOS remained queued. Review then reproduced an oversized metadata baseline within the count/path limits. The new publication/batch byte-budget fix passes 63 local source-library tests and scoped Clippy, and its focused owner/application regression workflow at `5aa08018` now passes on Linux/macOS/Windows. Combined producer acceptance is pending on this integration branch. Remaining resource/lifecycle acceptance, broader workspace checks and substantive review are still open. See [the scope integration design](file-observation-scope-design.md) and [implementation notes](file-observation-implementation.md).
 
 Setup ownership is expanded in [setup-design.md](setup-design.md). Its Store