diff --git a/scripts/clips/record.mjs b/scripts/clips/record.mjs
index 233bba38..7a3080af 100644
--- a/scripts/clips/record.mjs
+++ b/scripts/clips/record.mjs
@@ -35,9 +35,21 @@ const flag = (name) => {
   return hit.includes("=") ? hit.split("=").slice(1).join("=") : true;
 };
 const wanted = args.filter((arg) => !arg.startsWith("--"));
-const work = path.resolve(
-  flag("work") || path.join(os.tmpdir(), "donut-clips"),
-);
+
+/** The default scratch folder in the shared temp dir, closed to other users. */
+function privateTempDir(name) {
+  const dir = path.join(os.tmpdir(), name);
+  fs.mkdirSync(dir, { recursive: true, mode: 0o700 });
+  if (process.platform === "win32") return dir;
+  const stat = fs.lstatSync(dir);
+  if (!stat.isDirectory() || stat.uid !== process.getuid()) {
+    throw new Error(`${dir} is not your own folder; pass --work=DIR`);
+  }
+  fs.chmodSync(dir, 0o700);
+  return dir;
+}
+
+const work = path.resolve(flag("work") || privateTempDir("donut-clips"));
 const themes = flag("theme") ? [flag("theme")] : THEMES;
 for (const id of wanted) {
   if (!CLIPS[id]) throw new Error(`Unknown clip: ${id}`);
@@ -311,6 +323,7 @@ async function record(clip, name, theme) {
   fs.writeFileSync(
     path.join(framesDir, "frames.json"),
     JSON.stringify(take.frames),
+    { mode: 0o600 },
   );
   return take.frames;
 }
diff --git a/scripts/clips/take.mjs b/scripts/clips/take.mjs
index 51993a28..d2fbf964 100644
--- a/scripts/clips/take.mjs
+++ b/scripts/clips/take.mjs
@@ -353,7 +353,7 @@ export class Take {
         this.framesDir,
         `${String(this.frames.length).padStart(5, "0")}.png`,
       );
-      fs.writeFileSync(file, Buffer.from(data, "base64"));
+      fs.writeFileSync(file, Buffer.from(data, "base64"), { mode: 0o600 });
       this.frames.push({ t, file });
     }
   }
diff --git a/src-tauri/src/agent_tasks/chat_sync/syncer.rs b/src-tauri/src/agent_tasks/chat_sync/syncer.rs
index 1fab6d06..e8e52061 100644
--- a/src-tauri/src/agent_tasks/chat_sync/syncer.rs
+++ b/src-tauri/src/agent_tasks/chat_sync/syncer.rs
@@ -85,7 +85,7 @@ pub struct Files {
 }
 
 impl Files {
-  fn secrets(&self) -> PathBuf {
+  fn key_file(&self) -> PathBuf {
     self.dir.join("key.dat")
   }
 
@@ -98,7 +98,7 @@ impl Files {
   }
 
   fn load_secrets(&self) -> Option<Secrets> {
-    match crate::vault::open(&self.secrets(), SECRETS_MAGIC) {
+    match crate::vault::open(&self.key_file(), SECRETS_MAGIC) {
       Ok(Some(text)) => serde_json::from_str(&text).ok(),
       Ok(None) => None,
       Err(e) => {
@@ -112,7 +112,7 @@ impl Files {
     let Ok(text) = serde_json::to_string(secrets) else {
       return;
     };
-    if let Err(e) = crate::vault::seal(&self.secrets(), SECRETS_MAGIC, &text) {
+    if let Err(e) = crate::vault::seal(&self.key_file(), SECRETS_MAGIC, &text) {
       log::warn!("Agent chat sync key save failed err=\"{e}\"");
     }
   }
diff --git a/src-tauri/src/cookie_health.rs b/src-tauri/src/cookie_health.rs
index 3a93e188..51c2901d 100644
--- a/src-tauri/src/cookie_health.rs
+++ b/src-tauri/src/cookie_health.rs
@@ -309,6 +309,10 @@ pub fn log_before_launch(profile_id: &str, profile_data_dir: &Path) {
 mod tests {
   use super::*;
 
+  fn random_key() -> [u8; 32] {
+    rand::random()
+  }
+
   fn seal(key: &[u8; 32], host: &str, value: &[u8]) -> Vec<u8> {
     use sha2::{Digest, Sha256};
     let mut plain = Sha256::digest(host.as_bytes()).to_vec();
@@ -343,8 +347,8 @@ mod tests {
   fn reports_the_oldest_and_newest_rows_separately() {
     let dir = tempfile::tempdir().unwrap();
     let db = dir.path().join("Cookies");
-    let key = [7u8; 32];
-    let other = [9u8; 32];
+    let key = random_key();
+    let other = random_key();
     // Inserted newest first, so rowid order differs from creation order.
     cookie_db(
       &db,
@@ -374,8 +378,8 @@ mod tests {
   fn a_newest_row_that_does_not_open_is_an_error() {
     let dir = tempfile::tempdir().unwrap();
     let db = dir.path().join("Cookies");
-    cookie_db(&db, &[(1, seal(&[1u8; 32], "a.test", b"x"))]);
-    let store = inspect_cookies(&db, Some(&[2u8; 32])).unwrap();
+    cookie_db(&db, &[(1, seal(&random_key(), "a.test", b"x"))]);
+    let store = inspect_cookies(&db, Some(&random_key())).unwrap();
     let (level, line) = report("p", KeyFile::Present(32), KeyChange::Changed, Some(&store));
     assert_eq!(level, log::Level::Error);
     assert!(line.contains("key_changed=yes"));