diff --git a/codex-rs/core/src/git_info_tests.rs b/codex-rs/core/src/git_info_tests.rs
index d056a6e626..560f315a64 100644
--- a/codex-rs/core/src/git_info_tests.rs
+++ b/codex-rs/core/src/git_info_tests.rs
@@ -621,6 +621,7 @@ async fn get_git_repo_root_with_fs_starts_at_parent_for_file() {
     let proj = tmp.path().join("proj");
     let nested = proj.join("nested");
     std::fs::create_dir_all(proj.join(".git")).unwrap();
+    std::fs::write(proj.join(".git/HEAD"), "ref: refs/heads/main\n").unwrap();
     std::fs::create_dir_all(&nested).unwrap();
     let file = nested.join("file.txt");
     std::fs::write(&file, "contents").unwrap();
@@ -637,6 +638,7 @@ async fn get_git_repo_root_with_fs_ignores_metadata_errors() {
     let proj = tmp.path().join("proj");
     let nested = proj.join("nested");
     std::fs::create_dir_all(proj.join(".git")).unwrap();
+    std::fs::write(proj.join(".git/HEAD"), "ref: refs/heads/main\n").unwrap();
     std::fs::create_dir_all(&nested).unwrap();
     let fs = FailingMetadataFileSystem {
         path: PathUri::from_abs_path(&nested.join(".git").abs()),
@@ -654,6 +656,7 @@ async fn get_git_repo_root_with_fs_supports_windows_namespace_paths() {
     let tmp = TempDir::new().expect("tempdir");
     let repo = tmp.path().join("repo");
     std::fs::create_dir_all(repo.join(".git")).unwrap();
+    std::fs::write(repo.join(".git/HEAD"), "ref: refs/heads/main\n").unwrap();
     std::fs::create_dir_all(repo.join("nested")).unwrap();
 
     let namespace_repo = PathBuf::from(format!(r"\\?\{}", repo.display()));
@@ -855,3 +858,37 @@ fn test_git_info_serialization_with_nones() {
     assert!(!parsed.as_object().unwrap().contains_key("branch"));
     assert!(!parsed.as_object().unwrap().contains_key("repository_url"));
 }
+
+#[tokio::test]
+async fn get_git_repo_root_with_fs_ignores_empty_git_dir() {
+    skip_if_sandbox!();
+    let temp_root = TempDir::new().unwrap();
+
+    // Create an empty .git directory (e.g. from a bubblewrap mount)
+    let dot_git = temp_root.path().join(".git");
+    fs::create_dir(&dot_git).unwrap();
+
+    let nested = temp_root.path().join("nested");
+    fs::create_dir(&nested).unwrap();
+
+    assert_eq!(
+        get_git_repo_root_with_fs(LOCAL_FS.as_ref(), &nested.abs()).await,
+        None
+    );
+}
+
+#[tokio::test]
+async fn get_git_repo_root_with_fs_skips_empty_git_dir_for_valid_parent() {
+    skip_if_sandbox!();
+    let temp_root = TempDir::new().unwrap();
+    let repo = temp_root.path().join("repo");
+    let nested = repo.join("nested");
+    fs::create_dir_all(repo.join(".git")).unwrap();
+    fs::write(repo.join(".git/HEAD"), "ref: refs/heads/main\n").unwrap();
+    fs::create_dir_all(nested.join(".git")).unwrap();
+
+    assert_eq!(
+        get_git_repo_root_with_fs(LOCAL_FS.as_ref(), &nested.abs()).await,
+        Some(repo.abs())
+    );
+}
diff --git a/codex-rs/git-utils/src/info.rs b/codex-rs/git-utils/src/info.rs
index 115e26110d..958a79c560 100644
--- a/codex-rs/git-utils/src/info.rs
+++ b/codex-rs/git-utils/src/info.rs
@@ -50,19 +50,38 @@ pub async fn get_git_repo_root_with_fs(
     cwd: &AbsolutePathBuf,
 ) -> Option<AbsolutePathBuf> {
     let cwd_uri = PathUri::from_abs_path(cwd);
-    let base = match fs.get_metadata(&cwd_uri, /*sandbox*/ None).await {
+    let mut search_base = match fs.get_metadata(&cwd_uri, /*sandbox*/ None).await {
         Ok(metadata) if metadata.is_directory => cwd.clone(),
         _ => cwd.parent()?,
     };
-    find_nearest_native_ancestor_with_markers(
-        fs,
-        &base,
-        vec![".git".to_string()],
-        FindUpErrorPolicy::Ignore,
-        /*sandbox*/ None,
-    )
-    .await
-    .ok()?
+
+    loop {
+        let repo_root = find_nearest_native_ancestor_with_markers(
+            fs,
+            &search_base,
+            vec![".git".to_string()],
+            FindUpErrorPolicy::Ignore,
+            /*sandbox*/ None,
+        )
+        .await
+        .ok()??;
+        let dot_git = repo_root.join(".git");
+        let dot_git_uri = PathUri::from_abs_path(&dot_git);
+        let head_uri = PathUri::from_abs_path(&dot_git.join("HEAD"));
+        let objects_uri = PathUri::from_abs_path(&dot_git.join("objects"));
+        let (dot_git_metadata, head_metadata, objects_metadata) = tokio::join!(
+            fs.get_metadata(&dot_git_uri, /*sandbox*/ None),
+            fs.get_metadata(&head_uri, /*sandbox*/ None),
+            fs.get_metadata(&objects_uri, /*sandbox*/ None),
+        );
+        match dot_git_metadata {
+            Ok(metadata) if !metadata.is_directory => return Some(repo_root),
+            Ok(_) if head_metadata.is_ok() || objects_metadata.is_ok() => return Some(repo_root),
+            _ => {}
+        }
+
+        search_base = repo_root.parent()?;
+    }
 }
 
 /// Timeout for git commands to prevent freezing on large repositories
@@ -848,7 +867,13 @@ fn find_ancestor_git_entry(base_dir: &Path) -> Option<(PathBuf, PathBuf)> {
     loop {
         let dot_git = dir.join(".git");
         if dot_git.exists() {
-            return Some((dir, dot_git));
+            if dot_git.is_dir() {
+                if dot_git.join("HEAD").exists() || dot_git.join("objects").exists() {
+                    return Some((dir, dot_git));
+                }
+            } else {
+                return Some((dir, dot_git));
+            }
         }
 
         // Pop one component (go up one directory). `pop` returns false when
@@ -948,6 +973,31 @@ mod tests {
         }
     }
 
+    #[test]
+    fn get_git_repo_root_ignores_empty_git_directory() {
+        let temp_dir = tempfile::tempdir().expect("create temp dir");
+        std::fs::create_dir(temp_dir.path().join(".git")).expect("create empty .git");
+        let nested = temp_dir.path().join("nested");
+        std::fs::create_dir(&nested).expect("create nested directory");
+
+        assert_eq!(get_git_repo_root(&nested), None);
+    }
+
+    #[test]
+    fn get_git_repo_root_accepts_git_directory_with_head() {
+        let temp_dir = tempfile::tempdir().expect("create temp dir");
+        let dot_git = temp_dir.path().join(".git");
+        std::fs::create_dir(&dot_git).expect("create .git");
+        std::fs::write(dot_git.join("HEAD"), "ref: refs/heads/main\n").expect("write HEAD");
+        let nested = temp_dir.path().join("nested");
+        std::fs::create_dir(&nested).expect("create nested directory");
+
+        assert_eq!(
+            get_git_repo_root(&nested),
+            Some(temp_dir.path().to_path_buf())
+        );
+    }
+
     #[tokio::test]
     async fn local_git_branches_excludes_detached_head_entry() {
         let temp_dir = tempfile::tempdir().expect("create temp dir");
diff --git a/codex-rs/tui/src/chatwidget/tests/helpers.rs b/codex-rs/tui/src/chatwidget/tests/helpers.rs
index ac87d717d6..fb00b98a03 100644
--- a/codex-rs/tui/src/chatwidget/tests/helpers.rs
+++ b/codex-rs/tui/src/chatwidget/tests/helpers.rs
@@ -1285,6 +1285,7 @@ pub(super) fn strip_osc8_for_snapshot(text: &str) -> String {
 
 pub(super) fn plugins_test_absolute_path(path: &str) -> AbsolutePathBuf {
     std::env::temp_dir()
+        .join("codex_mock_cwd")
         .join("codex-plugin-menu-tests")
         .join(path)
         .abs()
diff --git a/codex-rs/tui/src/chatwidget/tests/review_mode.rs b/codex-rs/tui/src/chatwidget/tests/review_mode.rs
index b1f3360c0d..3611ab16ca 100644
--- a/codex-rs/tui/src/chatwidget/tests/review_mode.rs
+++ b/codex-rs/tui/src/chatwidget/tests/review_mode.rs
@@ -1381,7 +1381,7 @@ async fn review_branch_picker_escape_navigates_back_then_dismisses() {
     chat.open_review_popup();
 
     // Open the branch picker submenu (child view). Using a temp cwd with no git repo is fine.
-    let cwd = std::env::temp_dir();
+    let cwd = std::env::temp_dir().join("codex_mock_cwd");
     chat.show_review_branch_picker(&cwd).await;
 
     // Verify child view header.
diff --git a/codex-rs/tui/src/history_cell/tests.rs b/codex-rs/tui/src/history_cell/tests.rs
index c7a4ca801f..077d7120ac 100644
--- a/codex-rs/tui/src/history_cell/tests.rs
+++ b/codex-rs/tui/src/history_cell/tests.rs
@@ -33,7 +33,7 @@ use rmcp::model::Content;
 
 const SMALL_PNG_BASE64: &str = "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR4nGP4z8DwHwAFAAH/iZk9HQAAAABJRU5ErkJggg==";
 async fn test_config() -> Config {
-    let codex_home = std::env::temp_dir();
+    let codex_home = std::env::temp_dir().join("codex_mock_cwd");
     ConfigBuilder::default()
         .codex_home(codex_home.clone())
         .build()
@@ -44,7 +44,7 @@ async fn test_config() -> Config {
 fn test_cwd() -> PathBuf {
     // These tests only need a stable absolute cwd; using temp_dir() avoids baking Unix- or
     // Windows-specific root semantics into the fixtures.
-    std::env::temp_dir()
+    std::env::temp_dir().join("codex_mock_cwd")
 }
 
 #[test]
@@ -1534,7 +1534,7 @@ fn session_header_includes_reasoning_level_when_present() {
         "gpt-4o".to_string(),
         Some(ReasoningEffortConfig::High),
         /*show_fast_status*/ true,
-        std::env::temp_dir(),
+        std::env::temp_dir().join("codex_mock_cwd"),
         "test",
     );
 
@@ -1554,7 +1554,7 @@ fn session_header_hides_fast_status_when_disabled() {
         "gpt-4o".to_string(),
         Some(ReasoningEffortConfig::High),
         /*show_fast_status*/ false,
-        std::env::temp_dir(),
+        std::env::temp_dir().join("codex_mock_cwd"),
         "test",
     );
 
diff --git a/codex-rs/tui/src/markdown_stream.rs b/codex-rs/tui/src/markdown_stream.rs
index c3f2474b5b..3057ca6704 100644
--- a/codex-rs/tui/src/markdown_stream.rs
+++ b/codex-rs/tui/src/markdown_stream.rs
@@ -195,7 +195,7 @@ impl MarkdownStreamCollector {
 fn test_cwd() -> PathBuf {
     // These tests only need a stable absolute cwd; using temp_dir() avoids baking Unix- or
     // Windows-specific root semantics into the fixtures.
-    std::env::temp_dir()
+    std::env::temp_dir().join("codex_mock_cwd")
 }
 
 #[cfg(test)]
diff --git a/codex-rs/tui/src/streaming/controller.rs b/codex-rs/tui/src/streaming/controller.rs
index 95a3b72269..32f43f9d57 100644
--- a/codex-rs/tui/src/streaming/controller.rs
+++ b/codex-rs/tui/src/streaming/controller.rs
@@ -737,7 +737,7 @@ mod tests {
     fn test_cwd() -> PathBuf {
         // These tests only need a stable absolute cwd; using temp_dir() avoids baking Unix- or
         // Windows-specific root semantics into the fixtures.
-        std::env::temp_dir()
+        std::env::temp_dir().join("codex_mock_cwd")
     }
 
     fn stream_controller(width: Option<usize>) -> StreamController {
diff --git a/codex-rs/tui/src/streaming/mod.rs b/codex-rs/tui/src/streaming/mod.rs
index 576277aa3e..c3c697eedc 100644
--- a/codex-rs/tui/src/streaming/mod.rs
+++ b/codex-rs/tui/src/streaming/mod.rs
@@ -109,7 +109,7 @@ mod tests {
     fn test_cwd() -> PathBuf {
         // These tests only need a stable absolute cwd; using temp_dir() avoids baking Unix- or
         // Windows-specific root semantics into the fixtures.
-        std::env::temp_dir()
+        std::env::temp_dir().join("codex_mock_cwd")
     }
 
     #[test]
diff --git a/codex-rs/tui/src/update_action.rs b/codex-rs/tui/src/update_action.rs
index 0fe4408444..b300aabb01 100644
--- a/codex-rs/tui/src/update_action.rs
+++ b/codex-rs/tui/src/update_action.rs
@@ -85,9 +85,12 @@ mod tests {
 
     #[test]
     fn maps_install_context_to_update_action() {
-        let native_release_dir =
-            AbsolutePathBuf::from_absolute_path(std::env::temp_dir().join("native-release"))
-                .expect("temp dir path should be absolute");
+        let native_release_dir = AbsolutePathBuf::from_absolute_path(
+            std::env::temp_dir()
+                .join("codex_mock_cwd")
+                .join("native-release"),
+        )
+        .expect("temp dir path should be absolute");
 
         assert_eq!(
             UpdateAction::from_install_context(&InstallContext {