diff --git a/src/harness/cursor_desktop.rs b/src/harness/cursor_desktop.rs
index ec2e81e..d151537 100644
--- a/src/harness/cursor_desktop.rs
+++ b/src/harness/cursor_desktop.rs
@@ -1281,22 +1281,27 @@ impl Store for CursorDesktopStore {
     fn delete(&self, reference: &String) -> Result<()> {
         super::checked_id_component(CursorDesktop::NAME, reference)?;
         let conn = Connection::open(self.db_path()).map_err(sqlite_err)?;
-        let deleted: usize = conn
-            .execute(
+        let deleted_headers = if has_table(&conn, "composerHeaders")? {
+            conn.execute(
                 "DELETE FROM composerHeaders WHERE composerId = ?1",
                 params![reference],
             )
+            .map_err(sqlite_err)?
+        } else {
+            0
+        };
+        let deleted_kv: usize = conn
+            .execute(
+                "DELETE FROM cursorDiskKV WHERE key = ?1 OR key LIKE ?2 OR key LIKE ?3 OR key LIKE ?4",
+                params![
+                    format!("composerData:{reference}"),
+                    format!("bubbleId:{reference}:%"),
+                    format!("%:{reference}"),
+                    format!("%:{reference}:%"),
+                ],
+            )
             .map_err(sqlite_err)?;
-        conn.execute(
-            "DELETE FROM cursorDiskKV WHERE key = ?1 OR key LIKE ?2 OR key LIKE ?3",
-            params![
-                format!("composerData:{reference}"),
-                format!("bubbleId:{reference}:%"),
-                format!("%:{reference}%"),
-            ],
-        )
-        .map_err(sqlite_err)?;
-        if deleted == 0 {
+        if deleted_headers == 0 && deleted_kv == 0 {
             return Err(Error::Malformed {
                 harness: CursorDesktop::NAME,
                 detail: format!("no such session: {reference}"),
diff --git a/tests/integration/cursor_desktop.rs b/tests/integration/cursor_desktop.rs
index 8547b1f..c56ec3a 100644
--- a/tests/integration/cursor_desktop.rs
+++ b/tests/integration/cursor_desktop.rs
@@ -549,6 +549,20 @@ fn pending_tool_call_yields_no_result_message() {
     );
 }
 
+#[cfg(feature = "opencode")]
+#[test]
+fn delete_roundtrip_removes_session_and_fails_on_duplicate() {
+    let dir = tempfile::tempdir().unwrap();
+    let store = CursorDesktopStore::new(dir.path());
+    let saved = store.save(&sample_transcript()).unwrap();
+
+    assert_eq!(store.discover().unwrap().len(), 1);
+    store.delete(&saved.reference).unwrap();
+    assert_eq!(store.discover().unwrap().len(), 0);
+
+    assert!(store.delete(&saved.reference).is_err());
+}
+
 #[test]
 fn edit_tool_with_replace_all_survives_fixpoint() {
     let mut common = fixpoint_common();
@@ -674,6 +688,121 @@ fn edit_and_write_tools_normalize_and_denormalize_losslessly() {
     assert_eq!(back.body, common.body);
 }
 
+#[cfg(feature = "opencode")]
+#[test]
+fn delete_succeeds_on_database_without_composer_headers_table() {
+    let dir = tempfile::tempdir().unwrap();
+    let db_path = dir.path().join("globalStorage").join("state.vscdb");
+    std::fs::create_dir_all(db_path.parent().unwrap()).unwrap();
+
+    let conn = rusqlite::Connection::open(&db_path).unwrap();
+    conn.execute_batch(
+        "CREATE TABLE cursorDiskKV (key TEXT PRIMARY KEY, value TEXT);
+         INSERT INTO cursorDiskKV VALUES ('composerData:pre-table-1', '{}');
+         INSERT INTO cursorDiskKV VALUES ('bubbleId:pre-table-1:b1', '{}');",
+    )
+    .unwrap();
+
+    let store = CursorDesktopStore::new(dir.path());
+    store.delete(&"pre-table-1".to_string()).unwrap();
+
+    let count: i64 = conn
+        .query_row(
+            "SELECT count(*) FROM cursorDiskKV WHERE key LIKE '%pre-table-1%'",
+            [],
+            |r| r.get(0),
+        )
+        .unwrap();
+    assert_eq!(count, 0);
+
+    // Deleting again should fail with no such session
+    assert!(store.delete(&"pre-table-1".to_string()).is_err());
+}
+
+#[cfg(feature = "opencode")]
+#[test]
+fn delete_succeeds_on_kv_only_session_in_modern_database() {
+    let dir = tempfile::tempdir().unwrap();
+    let db_path = dir.path().join("globalStorage").join("state.vscdb");
+    std::fs::create_dir_all(db_path.parent().unwrap()).unwrap();
+
+    let conn = rusqlite::Connection::open(&db_path).unwrap();
+    conn.execute_batch(
+        "CREATE TABLE composerHeaders (composerId TEXT PRIMARY KEY, recency INTEGER);
+         CREATE TABLE cursorDiskKV (key TEXT PRIMARY KEY, value TEXT);
+         INSERT INTO cursorDiskKV VALUES ('composerData:kv-only-1', '{}');
+         INSERT INTO cursorDiskKV VALUES ('bubbleId:kv-only-1:b1', '{}');",
+    )
+    .unwrap();
+
+    let store = CursorDesktopStore::new(dir.path());
+    store.delete(&"kv-only-1".to_string()).unwrap();
+
+    let count: i64 = conn
+        .query_row(
+            "SELECT count(*) FROM cursorDiskKV WHERE key LIKE '%kv-only-1%'",
+            [],
+            |r| r.get(0),
+        )
+        .unwrap();
+    assert_eq!(count, 0);
+
+    assert!(store.delete(&"kv-only-1".to_string()).is_err());
+}
+
+#[cfg(feature = "opencode")]
+#[test]
+fn delete_exact_session_id_does_not_delete_prefixed_sibling() {
+    let dir = tempfile::tempdir().unwrap();
+    let db_path = dir.path().join("globalStorage").join("state.vscdb");
+    std::fs::create_dir_all(db_path.parent().unwrap()).unwrap();
+
+    let conn = rusqlite::Connection::open(&db_path).unwrap();
+    conn.execute_batch(
+        "CREATE TABLE composerHeaders (composerId TEXT PRIMARY KEY, recency INTEGER);
+         CREATE TABLE cursorDiskKV (key TEXT PRIMARY KEY, value TEXT);
+         INSERT INTO composerHeaders VALUES ('session-1', 100);
+         INSERT INTO composerHeaders VALUES ('session-10', 200);
+         INSERT INTO cursorDiskKV VALUES ('composerData:session-1', '{}');
+         INSERT INTO cursorDiskKV VALUES ('bubbleId:session-1:b1', '{}');
+         INSERT INTO cursorDiskKV VALUES ('checkpointId:session-1:c1', '{}');
+         INSERT INTO cursorDiskKV VALUES ('composerData:session-10', '{}');
+         INSERT INTO cursorDiskKV VALUES ('bubbleId:session-10:b1', '{}');
+         INSERT INTO cursorDiskKV VALUES ('checkpointId:session-10:c1', '{}');",
+    )
+    .unwrap();
+
+    let store = CursorDesktopStore::new(dir.path());
+    store.delete(&"session-1".to_string()).unwrap();
+
+    let count_s10_headers: i64 = conn
+        .query_row(
+            "SELECT count(*) FROM composerHeaders WHERE composerId = 'session-10'",
+            [],
+            |r| r.get(0),
+        )
+        .unwrap();
+    assert_eq!(count_s10_headers, 1);
+
+    let remaining_s10_keys: i64 = conn
+        .query_row(
+            "SELECT count(*) FROM cursorDiskKV WHERE key LIKE '%session-10%'",
+            [],
+            |r| r.get(0),
+        )
+        .unwrap();
+    assert_eq!(remaining_s10_keys, 3);
+
+    let remaining_target_keys: i64 = conn
+        .query_row(
+            "SELECT count(*) FROM cursorDiskKV WHERE key LIKE '%session-1%' AND key NOT LIKE '%session-10%'",
+            [],
+            |r| r.get(0),
+        )
+        .unwrap();
+    assert_eq!(remaining_target_keys, 0);
+}
+
 #[cfg(feature = "opencode")]
 #[test]
 fn store_resolves_workspace_id_with_percent_encoding_and_spaces() {